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PROPERTY OF
University of
Michigan
Libraries
1817
ARTES SCIENTIA VERITAS
Digitized by Google
Digitized by Google
APPLETON'S
DICTIONARY
OF
MACHINES, MECHANICS, ENGINE-WORK,
AND
ENGINEERING.
ILLUSTRATED WITH FOUR THOUSAND ENGRAVINGS ON WOOD.
IN TWO VOLUMES.
VOLUME I.
NEW YORK:
D. APPLETON & COMPANY, 200 BROADWAY.
MDCCC LII.
Digitized by Google
Engin. Library
T
9
,A67
V.I
Entered according to Act of Congress, in the year 1851,
By D. APPLETON & COMPANY,
1 the Clerk's Office of the District Court of the United States for the Southern District 11
Now York.
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Engineering
List
6-18-64
PREFACE.
ENCYCLOPEDIAS and Dictionaries of Art have now become so popular, and their ad-
vantages so thoroughly tested, that it is entirely unnecessary to usher in the present work
by dwelling on the peculiar merits of such publications. Every such work marks the era,
or defines the position of the sciences treated, at its time of publication; and, in the lapse
of years, is record of a step by which such sciences have advanced, affording material for
history rather than practical working examples. On this account the older encyclopæ-
dias have become almost useless to the practical man of the present day; but the later
the works, the greater their value-provided they are, as they should be, latest records of
the progress of science.
No work like the one now offered to the public has ever originated here; and of the
foreign works republished, none occupy the same ground, or exhibit, in the slightest de-
gree, the state of mechanical arts in this country. The Dictionary is intended to be
a Dictionary of Machines, Mechanics, Engine-work and Engineering ; to present con-
cisely and compendiously the details of valuable machines in actual use, the laws of
matter and their application, the construction and proportion of parts of engines and
mill-work, together with the most successful and useful examples in engineering.
In the progress of nations, it has always been remarked that the more liberal the gov-
ernment, the more rapid are the strides and the greater the advance in mechanical and
industrial pursuits, and nowhere in history can a more brilliant illustration of this be
found than in the progress of our own country rich in natural resources, under a free
and beneficent government, industry is encouraged and protected, yet comparatively
sparsely populated, the country cannot, to the fullest extent, develop its resources or
compete with the overstocked and poorly paid population of the older countries, unless
machines are brought to supply the place of manual labor. Without encroaching on the
grounds of Free Trade or Protection, it is evident that, to stand on fair ground with
our competitors, we must understand the machines and processes employed by them,
that these machines must be adapted or improved by us if possible, or new ones invented
better to suit our resources and develop them.
To show, therefore, the advance of the mechanical arts both here and abroad, to de-
fine their exact position at the present time as far as possible, but more particularly in
regard to machinery, to make, as it were, a " World Industrial Exhibition" of useful ma-
chines, and a record of their application, is the object of the present work. For this
purpose the editors have drawn from the publications of all countries distinguished in
mechanical pursuits. Care has been taken, in selection, to admit only such as are con-
sidered standard and practical. In many cases, credit has been given for these selections
at the end of the articles; annexed also, a list of the books is given, from which selections
were made. But credit is to be given especially to the Glasgow Engineer's and Machin-
ist's Assistant, BOURNE on the Steam-Engine, HOLTZAPFFEL'S Turning and Mechanical
Manipulation, Allgemeine Maschinen Encyclopädie, from which very able articles have
been drawn.
But whilst we have drawn largely from foreign works, we have not been unmindful
of our own progress in mechanism and engineering. Many patentees of valuable ma-
chines have kindly afforded us drawings and descriptions, among whom we would name
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8
PREFACE.
E. B. BIGELOW, Esq., HENRY BURDEN, WM. MASON, G. H. CORLISS, JOHN J. HOWE,
and many others. Very many drawings and specifications have been taken from the
Patent Office, and descriptions will be found in this work of machines which cannot be
seen in operation; as, from a mistaken consideration of the patentees, they are not open
to inspection of visitors. We are also under obligations to WM. A. BURKE, of the Lowell
Machine Shop, CALEB M. MARVEL, of the Essex Machine Shop, and WM. ELLIS, of the
Washington Navy Yard, for drawings and descriptions of machines.
In the Engine department, we are under obligations to Mr. COPELAND for the draw-
ings and descriptions of the steamer Pacific. In Engineering, we owe much to the
liberality of WILLIAM J. MCALPINE, in furnishing us with the description of the Dry
Dock at Brooklyn, and the machinery used in its construction, together with the experi-
ments made on the strength of the gates. The article GOLD has been furnished by a
distinguished metallurgist. The article on METALLURGY is by F. OVERMAN, whose work
on Iron stands deservedly high. The original communications have been numerous and
valuable, and the publishers have spared neither labor nor expense to make the work
what it should be.
The illustrations have all been engraved expressly for the work, as large as the page
would admit, and sufficiently distinct and in detail to answer for working drawings.
The work is intended more directly for the practical and working man, and for those
interested in industrial pursuits but to all classes it will be found important and instruc-
tive. It will show how far the world has progressed in mechanical science-the science
of automatic labor, the science which is destined to raise our country to the most elevated
position in the world, to ennoble the mechanic and artisan, and to extend and diffuse
knowledge.
Among the works from which materials have been selected may be mentioned the
following:
Annales des Ponts et Chaussées. Bibliothèque des Arts Industriels: (Masson, Paris.) Civil En-
gineer and Architect's Journal: (London.) Engineer and Machinist's Assistant: (Blackie, Glasgow.)
Publication Industrielle: (Armengaud Ainé, Paris.) Jamieson's Mechanics of Fluids. Treatise on
Mechanics: (Poisson.) Allgemeine Bauzeitung mit Abbildungen (Förster, Wien.) Organ für die
Fortschritte des Eisenbahnwesens in technischer Beziehung: (Von Waldegg, Wiesbaden.) Glasgow
Practical Mechanic. Silliman's Journal. Allgemeine Maschinen-Encyclopädie-Hilsse (Leipzig.)
Cotton Manufacture of Great Britain and America contrasted. Holtzapffel's Turning and Mechanical
Manipulation. The Steam-Engine: (J. Bourne.) Eisenbahn-Zeitung (Stuttgart.) Tredgold on the
Steam-Engine. Dictionnaire des Arts et Manufactures: (Laboulaye, Paris.) Origin and Progress of
Steam Navigation: (Woodcroft.) Essai sur l'Industrie des Matières Textiles: (Michel Alcan, Paris.)
Griers' Mechanic's Pocket Dictionary. Templeton's Millwrights and Engineer's Pocket Companion.
Marine Steam-Engine: (Brown.) Weisbach's Mechanics and Engineering. Barlow on Strength of
Materials. Hann's Mechanics. Mechanical Principles of Engineering and Architecture: (Mosely.)
Journal of the Franklin Institute. The Transactions of the Institute of Civil Engineers: (London.)
The Artisan. Quarterly Papers on Engineering (Published by Weale, London.) Imperial Dictionary
-Blackie: (Glasgow.) Professional Papers of the Corps of Royal Engineers. Student's Guide to the
Locomotive-Engine. Railway Engine and Carriage-Wheels: (Barlow, London.) Recueil des Machines
Instrumens et Appareils: (Le Blanc, Paris.) Buchanan on Mill-Work. Practical Examples of Modern
Tools and Machines: (G. Rennie.) Repertoire de l'Industrie Française et Etrangère: (L. Mathias,
Paris.) Treatise on the Manufacture of Gas: (Cleg, London.) Hodge on the Steam-Engine. Scien-
tific American. Railroad Journal: (New York.) American Artisan. Mechanics' Magazine (London.)
Nicholson's (Peter) Dictionary of Architecture. Dictionnaire de Marine a Voiles et à Vapeur: (De
Bonnefoux, Paris.) Conway and Menai Tubular Bridges: (Fairbairn.) Brees' Railway Practice. Bar-
low's Mathematical Dictionary. Bowditch's Navigation. Gregory's Mathematics for Practical Men.
Engineers' and Mechanics' Encyclopeedia (Luke Herbert.) Patent Journal: (London.) Brees' Glos
sary of Engineering. Encyclopedia of Civil Engineering: (Cresy.) Craddock's Lectures on the Steam-
Engine. Assistant Engineer's Railway Guide: (Haskoll.) Mechanical Principia: (Leonard.) Weale's
Mathematical Tables.
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A DICTIONARY
OF
MACHINES, MECHANICS, ENGINE-WORK,
AND ENGINEERING.
AAM. A measure of liquids among the Dutch, equal 288 pints.
ABACUS. An instrument employed by the ancients for facilitating calculations similar to that now
frequently employed for teaching children the rudiments of arithmetic, and which is commonly sold in
our stationers' shops. It usually consists of twelve parallel wires, fixed in a light rectangular frame
each wire carrying 12 beads or balls. There are thus 12 times 12, answering to the common multipli-
cation table, all the results of which it demonstrates to the dullest capacity. All the operations of ad-
dition or subtraction are likewise performed by it, by merely moving the beads from one side to the
other of the frame. By thus smoothing the difficulties of acquiring arithmetical knowledge at the very
outset, and rendering it quite obvious and amusing at the same time, the apparatus becomes one of
considerable importance in education.
Another kind of Abacus consists of a series of parallel wires fixed in a frame like the former. On
each wire there are nine little balls; the lowest stand for units, the next above for tens, the next hun-
Fig. 1.
c
Millions
Hundreds of Thousands
Tens of Thousands
Thousands
Hundreds
Tens
Units
dreds, and so on up to any number. The frame is divided into two compartments, a and b, by a cross
wire at c, which is sufficiently raised above the wires to allow the little balls to slide under it. Suppose
the whole 63 balls to be placed in the compartment a, and it be proposed to note the sum of 4,346,072;
it is effected by sliding the balls shown in b from their previous situation in a.
ABELE See WOODS, varieties of.
ABSORBING AND PRODUCTIVE CASCADE an apparatus of great utility and elegance, in-
vented by M. Clement. It is known that the absorption or solution of the gases takes place in
proportion to the pressure on the absorbing liquid, the extent of surface exposed to the absorbing action,
and to the length of time in which it is exposed. If the pressure, however, be very great, the vessels
are liable to rupture and it therefore becomes an important object to strengthen the influence of the
other two principles just mentioned, which has been obtained in a very eminent degree by the invention
of M. Clement. In this apparatus, which is represented in the annexed diagram, the gas has no press-
are to sustain, but the surfaces of its contact are exceedingly multiplied and extended.
The column a is filled with a great number of small bilbs of glass or porcelain, its lower extremity
resting in another cylinder b, of greater diameter, in which is a cavity adapted to the reduced diame-
ter of the column, which communicates with two small tubes c, d, the former being employed to
introduce the gas, and the latter to discharge the liquid. At e is a reservoir of water, with a con-
ducting pipe f, the supply therefrom being regulated by a cock g. The water, in its passage to the
lower part of the column, successively moistens all the small spheres, and being thus impeded in its
progress, a very considerable time is occupied in its descent. On the other hand, the gas, as it is
introduced, occupying all the vacant interstices, becomes infinitely divided and therefore, as it can only
pass through the intermediate spaces very slowly, the duration of the contact is much prolonged, and the
absorption promoted. The inventor calculates that the absorbing power of this apparatus is 322 times
greater than the ordinary simple vessels used for the purpose. Although M. Clement, in making this
2
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10
ABUTMENT.
comparison, has unquestionably selected the
most unfavorable case, it must be admitted
that his absorbing cascade possesses great
advantages. To the apparatus thus de-
2.
scribed, M. Clement adapts another, which
he calls " the Productive Cascade," shown
in combination in our diagram. It is intend-
ed to produce gas for a considerable period
7
of time, and in a more convenient and less
expensive manner than by the ordinary
methods. Suppose, for example, it is re-
n
quired to prepare oxymuriatic acid or chlo-
rine; a large vessel h, provided with four
openings, is filled with oxide of manganese,
broken into large pieces; the opening i is
by a tube connected to a leaden vessel k,
containing common salt and sulphuric acid.
By the tube l, a small stream of water is
made to flow from the reservoir above,
which gradually moistens the whole surface
of the pieces of manganese, and permits the
muriatic acid gas to attack and dissolve it
b
very easily. The chlorine which is produced
passes by the tube n, into the absorbing
cascade, while the muriate of manganese is
carried off as it forms, by the water, through
the tube o, into the reservoir p. By this
arrangement, there is no occasion to reduce
the manganese to powder, and a much larger
quantity may be operated on at the same
time, without the operator being under the
necessity of frequently renewing the charge
of materials, and dismounting his apparatus.
ABUTMENT is a term commonly ap-
plied by engineers to those fixed parts of me-
chanism whence a resisting or reacting force
is obtained. See RAILWAY ENGINEERING.
ABUTMENTS, block, in course and rubble. See RAILWAY ENGINEERING.
ACACIA. See WOODS, varieties of.
ACCELERATION is the increase of velocity in a moving body, caused by the continued action of
the motive force. When bodies in motion pass through equal spaces in equal times, or, in other words,
when the velocity of the body is the same during the period that the body is in motion, it is termed
uniform motion, of which we have a familiar instance in the motion of the hands of a clock over the
face of it; but a more correct illustration is the revolution of the earth on its axis. In the case of a
body moving through unequal spaces in equal times, or with a varying velocity, if the velocity increase
with the duration of the motion, it is termed accelerated motion; but if it decrease with the duration of
the motion, it is termed retarded motion. A stone thrown up in the air, affords an illustration of both
these cases, the motion during the ascent being retarded by the force of gravity, and accelerated by the
same during the descent of the stone. All bodies have a tendency to preserve their state, either of rest
or of motion; so that if a body were set in motion, and the moving force were withdrawn, the body, if
unopposed by any force, would continue to move with the same velocity it had acquired at the instant
the moving force was withdrawn. And if a body in motion be acted upon by a constant force, (as the
force of gravity,) the motion becomes accelerated, the velocity increasing as the times, and the whole
spaces passed through increasing as the square of the times whilst the proportional spaces passed
through during equal portions of time, will be as the odd numbers, 1, 3, 5, 7, &c.; and the space passed
over in any portion of time will be equal to half the velocity acquired at the end of such time: which
results will be better brought to view in the following Table:
Times.
Velocities.
Spaces for each Time.
Total Space.
1
1
1
1-12
2
2
3
3+1-4-?
3
3
5
5+3+1-9-3²
4
4
7
7+5+3+1-16-4
It has been ascertained by experiment, that a body falling freely by its own weight from a state of
rest, will descend through 16 feet 1 inch in the first second of time, and will have acquired a velocity
of 321 feet; but from the rapidity with which the velocity increases,
cannot extend the experiment,
for in only four seconds a body falling freely would pass through
-pace of 256 feet. But by an
ingenious contrivance of Mr. Atwood, the laws of motion above laid
vn may be verified experiment-
ally. The machine is called Atwood's machine," after the name of the inventor; and the principle
of its action consists in counteracting a portion of the gravitating power of a body, by the gravitating
power of a smaller body; so that the absolute velocity, and the spaces passed through, shall be less
than in the case of bodies descending freely, whilst, as the force is constant, the same ratio of progres-
sion will hold in both cases. The annexed figure represents one of these machines. a a a is a triangular
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ACCELERATIONS.
11
frame upon three moveable legs; b, a small platform suspended from it by a universal joint c c, and
supporting two upright standards dd, in which the axis of a light brass wheel e revolves with very little
friction. Over a groove in the periphery of the wheel passes a very light and pliable silk thread, from
the ends of which hang two equal weights f, g. Into the under side of b is screwed a square rod h,
descending to the floor, to which it is secured in a perpendicular position by small pins passing through
holes in the claws at ii. On the face of the rod is a scale of inches; k is a
brass guide, fixed at the upper part of the rod h, so that when the top of the
weight g touches the lower side of k, the under side of g is on a level with
3.
the top, or commencement of the scale; l is a small stage, moveable along
the rod h, and having a hole in it sufficiently large for the weight g to pass:
on one side is a tightening screw m: n is another moveable stage, fitted with
a tightening screw o, as also a fork p, turning upon a hinge. The experi-
ments are conducted as follows small circular weight is placed upon g,
which is pulled up to the top of the scale, and the stage n is screwed to the
rod h, on a level with the lower part of the weight f, which is held down
upon it by the fork p. Upon releasing f from the fork, the weight g descends
with a slow, but gradually accelerated motion, and the number of inches the
weight has descended, at each successive beat of a pendulum, (suspended
from another triangle,) is observed upon the scale; and if the additional
weight be such as to cause g to descend through three inches in the first
second, then it will cause it to descend through one foot in two seconds, and
through 61 feet in five seconds. If the additional weight be removed, and a
small bar of equal weight, but of a length exceeding the diameter of the
hole in l, be placed upon g, and the stage l be set at any division of the
scale, at which the weight would arrive at the end of any number of seconds,
the stage will intercept the bar in its descent, and the weight will continue
to descend with the velocity it had acquired upon reaching 1. Thus, if the
velocity at the end of the second second be two feet, in which case the
weight would have descended one foot in that time, if the stage be set at one
foot upon the scale, it will intercept the bar at the end of the second second,
and the weight g will move with a uniform velocity of two feet per second,
through the remaining portion of its descent. If it is required to illustrate
the case of retarded motion, the small circular weight is placed upon the
weight g, and a similar small weight upon the weight f, so that g, still out-
weighing f, will descend; but as soon as the stage l intercepts the bar with
the small weight upon it, f becomes the heaviest, and g will descend with a
velocity decreasing as the squares of the times, counted from the time of g
passing the stage 1.
ACCELERATIONS, composition of. See PHORONOMY.
ACCELERATIONS, combination of velocity, and See PHORONOMY
ACCIDENTS IN BORING. See RAILWAY ENGINEERING.
ACID, carbonic, sulphurous. See NUMERICAL DATA and principal laws of the steam-engine.
AERIAL PERSPECTIVE, is that which represents objects diminished in size and weakened in tint
in proportion to their distance from the eye; but the term relates principally to the color.
AFFINITY, a term used in chemistry to denote that kind of attraction by which the particles of
different bodies unite, and form a compound possessing properties distinct from any of the substances
which compose it. Thus, when an acid and alkali combine, a new substance is formed, called a salt,
perfectly different in its chemical properties from either an acid or an alkali and the tendency which
these have to unite, is said to be in consequence of affinity.
AFRICAN BLACKWOOD. See WOODS, varieties of.
AIR ESCAPE, a simple and ingenious contrivance for letting off the air from water-pipes. If a
range of water-pipes be led over a rising ground, it will be found that air will collect in the higher
parts and obstruct the progress of the water; to remedy which inconvenience the Air Escape is employed.
A hollow vessel is attached to the upper part of the pipe, in the top of which vessel there is fixed a ball
cock, adjusted in such a way, that when any air collects in the pipe, it will ascend into the vessel, and
by displacing the water, cause the ball to descend, and thus open the cock, when the air is allowed to
escape. No water, however, can escape, for when that fluid rises in the vessel above a certain height,
the ball rises and shuts the cock; new air then collects, displaces the water, lowers the ball, the cock is
opened, and it again escapes.
AIR-GUN. A machine in which highly-compressed air is substituted for gunpowder to expel the
ball, which will be projected forward with greater or less velocity, according to the state of condensa-
tion, and the weight of the body projected. The effect will, therefore, be similar to that of a gun
charg with gunpowder, for inflamed gunpowder is nothing more than air very greatly condensed, so
that the two forces are exactly timilar. There is this important consideration to be attended to,
namely, that the velocities with which balls are impelled are directly proportional to the square root of
the forces; so that if the air in an air-gun be condensed only ten times, the velocity will be equal to
one-tenth of that arising from gunpowder; if condensed twenty times, the velocity would be one-
seventh that of gunpowder, and so on. Air-guns, however, project their balls with a much greater
velocity than that assigned above, and for this reason, that, as the reservoir or magazine of condensed
air is commonly very large in proportion to the tube which contains the ball, its density is very little
altered by passing through that narrow tube, and consequently the ball is urged all the way by nearly
the same force as at the first instant; whereas the elastic fluid arising from inflamed gunpowder is but
very small indeed in proportion to the tube or barrel of the gun, and therefore, by dilating into a com-
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12
AIR-VALVE.
paratively large space as it urges the ball along the barrel, its force is proportionally weakened, and it
always acts less and less on the ball in the tube. Hence it happens, that air condensed only ten times
into a pretty large receiver, will project its ball with a velocity little inferior to that of gunpowder.
Having thus explained the principle of the machine, we shall proceed to describe the construction of
one. It consists of a lock, stock, barrel, ramrod, &c., of about the size and weight of a common fowling-
piece. Under the lock at b is screwed a hollow copper ball c, perfectly air-tight. This ball is fully
charged with condensed air, by means of the syringe B, previous to its being applied to the tube at b.
Being charged and screwed on as above stated, if a bullet be rammed down in the barrel, and the
trigger a be pulled, the pin in b will, by the spring-work in the lock, forcibly strike out into the ball,
and thence by pushing it suddenly, a valve within it will let out a portion of the condensed air, which,
rushing through the aperture in the lock, will act forcibly against the ball, impelling it to the distance
of 60 or 70 yards, or farther if the
air be strongly compressed. At
every discharge only a portion of
the air escapes from the ball;
therefore, by re-cocking the piece
4.
another discharge may be made,
which may be repeated for a num-
c
ber of times proportioned to the
size of the ball. The air in the
copper ball is condensed by the
syringe B in the following manner.
The ball is screwed quite close on
the top of the syringe; at the end
of the steel-pointed rod a is a stout
ring, through which passes the rod
k; upon this rod the feet should be
firmly set; then the hands are to
h
be applied to the two handles i i
fixed on the side of the barrel of the
syringe, when, by moving the bar-
k
rel B steadily up and down on the
rod a, the ball c will become charged with condensed air, and the progress of condensation may be esti-
mated by the increasing difficulty in forcing down the syringe. At the end of the rod k is usually a square
hole, that the rod may serve as a key for attaching the ball to either the gun or syringe. In the inside
of the ball is fixed a valve and spring, which gives way to the admission of the air, but upon its emission,
comes close up to the orifice, shutting out the external air. The piston-rod works air-tight by a collar
of leather on it, in the barrel B; it is therefore obvious, that when the barrel is drawn up, the air will
rush in at the hole h; when`it is pushed down, it will have no other way to pass from the pressure of
the piston but into the ball c at the top. The barrel being drawn up, the operation is repeated, until
the condensation is so great as to resist the action of the piston. If air be very suddenly compressed
into a small compass, the heat given out is 80 considerable as to be sufficient to ignite inflammable sub-
stances. This discovery was made, accidentally, by a French soldier, who, in cleaning his musket with
some wadding fastened to the ramrod, found, after thrusting the ramrod suddenly down the piece, that
the wadding had ignited. The fact he communicated to the National Institute, and repeated the experi-
ment in their presence. This property has been turned to advantage in an apparatus denominated, An
Instantaneous Light Machine," constructed in a walking-stick, which consists of a piston accurately
fitted and worked in a cylinder, by the sudden stroke of which the volume of air contained in the
cylinder becomes so much compressed as to give out sufficient heat to set fire to a piece of the substance
termed German tinder.
AIR-VALVE, a valve commonly applied to steam-boilers for the purpose of preventing the forma-
tion of a vacuum when the steam happens to be condensed within the boiler. The mode of action of
these valves is very simple. A valve in the top of the boiler opening inwards, is kept shut by a eoun-
terweight at the end of a lever; but whenever the steam in the boiler happens to be condensed, a
vacuum is formed, and the air-valve is opened by the pressure of the atmosphere, consequently the air
enters and destroys the vacuum. The interior of the boiler being allowed to remain in the state of
vacuum, the atmospheric pressure from without might cause its sides to collapse, and thus effect the
destruction of the boiler. There have been instances of boilers collapsing even though furnished with
an air-valve, but in this case the counterweight must have been too great, or the valve itself too small;
an error which we fear is pretty common, and ought to be avoided.
AIR-VESSEL, a chamber containing air, attached to pumps and other water-works, the use of
which is to make the discharge constant, where the supply of water is intermittent. In the forcing-
pump for instance, where the water has to be sent up through a long range of pipes, the discharge
from the pump being irregular, the impetus of the water at every stroke would jolt the machinery,
which, however, may be prevented by an air-vessel. The ejection-pipe of the pump leads into a cham-
ber containing air, and this chamber communicates with the pipes through which the water is to flow,
the latter being less in diameter than the former. Now, when water by a stroke of the pump is sent
into the air-vessel, the air within it will be compressed, and before the pump has made another injection
into this vessel, the air will by its elastic power force the water in a constant stream up the pipes, and
thus a continuous stream is kept in the rising main. Air-vessels are with great advantage applied to
the suction-end of a pump.
AIR LEAKS. how to detect. See DETAILS OF ENGINES.
AIR IN MOTION, OR WIND AND WINDMILLS. Pure air consists almost entirely of azote or
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AIR IN MOTION.
13
nitrogen, and oxygen gases, with a very small portion of carbonic acid gas. Of 100 parts of air, reckon-
ing by weight, 75.55 parts are nitrogen, 23.32 oxygen, and 1.13 carbonic acid and watery vapor. Both
as respects weight and bulk, nitrogen forms the chief ingredient of the atmosphere.
The weight or pressure of the atmosphere is equal to the weight of a column of water 34 feet in height,
or to a column of mercury 30 inches in height, or 14.7 lbs. per square inch at a mean temperature. But
air and all kinds of gases are rendered lighter by the application of heat, for then the particles of the
mass are repelled from each other or rarefied, and occupy a greater space. Rarefied air, being specifi-
cally lightest, mounts above that of common density; hence, change of temperature is the principal cause
of winds.
Some winds occur from the following cause :-When a condensation of vapor in the atmosphere sud-
denly takes place, giving rise to clouds, which speedily fall in rain, the temperature of the surrounding
air is sensibly altered, and the colder rushing in upon the warmer, gives rise to a sudden gust of wind.
The most remarkable winds are those which traverse the ocean steadily in one direction, and are call-
ed trade winds, from their use to mercantile navigation. Their external limits are 30 degrees on each
side the equator; but each limit diminishes as the sun advances to the opposite tropic.
The force of effect and common appellations given to winds at different velocities are exhibited in the
following table :-
The impulse of wind increases as the
Velocity of the Wind.
Force or Pressure
square of its velocity; and the force or
per Sq. Foot, in
Common Appellations of the
Miles per
Feet per
Force of the wind.
pressure per square foot, in lbs., as the
lbs. Avoirdu-
Hour.
Second.
pois.
square of the velocity multiplied by
.002288.
1
1.47
.005
Hardly perceptible.
Windmills are constructed either 80
2
2.93
.020
that the sails shall move in a horizon-
3
4.40
.044
Just perceptible.
tal plane, or in a plane nearly vertical
4
5.87
.079
the former are called horizontal, and
5
7.33
.123
Gentle pleasant wind.
the latter vertical windmills.
10
14.67
.492
The sails of a windmill may be sup-
15
22.00
1.107
Pleasant brisk gale.
posed to intercept a cylinder of wind;
20
29.34
1.968
and it would seem that when the whole
25
36.67
3.075
Very brisk.
cylinder is intercepted, the effect of the
30
44.01
4.429
machine is diminished; hence it is con-
35
51.34
6.027
High winds.
cluded, from experiments, that the sails
40
58.68
7.873
should not intercept above fths of the
45
66.01
9.963
Very high.
cylinder.
50
73.35
12.300
A storm or tempest.
The wind does not act perpendicularly
60
88.02
17.715
A great storm.
on the sails of a windmill, but at a cer-
80
117.36
31.490
A hurricane.
tain angle; and the sail varies in the
degree of its inclination at different dis-
tances from the centre of motion, in resemblance to the wing of a bird, and which is termed the weath-
ering of the sail. The angles of weathering, as recommended by Smeaton, are as follows :-the radius
or whip being divided into 6 equal parts, and the first part from the centre being called 1, the last or
end of the sail, 6.
Deductions from Smeaton's experiments on Wind-
Distance from
Angle with the
Angle with the
mills.-1. The velocity of windmill sails, whether
the Centre.
Axis.
Plane of Motion.
unloaded or loaded, so as to produce a maximum, is
nearly as the velocity of the wind, their shape and
1
72°
18°
position being the same.
2
71
19
2. The load at the maximum is nearly, but some-
3
72
18
what less than, as the square of the velocity of the
4
74
16
wind, the shape and position of sails being the same.
5
773
12}
3. The effects of the same sail at a maximum are
6
83
7
nearly, but somewhat less than, as the cubes of the
velocity of the wind.
4. The load of the same sails at the maximum is nearly as the squares, and their effect as the cubes
of their number of turns in a given time.
5. When sails are loaded, so as to produce a maximum at a given velocity, and the velocity of the
wind increases, the load continuing the same :-1st. The increase of effect, when the increase of the ve-
locity of the wind is small, will be nearly as the square of those velocities. 2d. When the velocity of
the wind is double, the effects will be nearly as 10: ;-and 3d. When the velocities, compared, are
more than double of that where the given load produces a maximum, the effects increase nearly in a
simple ratio of the velocity of the wind.
6. In sails of a similar figure and position, the number of turns in a given time will be reciprocally
as the radius or length of the sail.
7. The load, at a maximum, that sails of a similar figure and position will overcome, at a given dis-
tance from the centre of motion, will be as the cube of the radius.
8. The effects of sails of similar figure and position are as the square of the radius.
9. The velocity of the extremities of Dutch sails, as well as of the enlarged sails, in all their usual
positions when unloaded, or even loaded to a maximum, is considerably quicker than the velocity of
the wind.
General Proposition.-That all planes, however situated, that intercept the same section of the wind,
and having the same relative velocity in regard to the wind, when reduced into the same direction, have
equal powers to produce mechanical effects.
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14
AIR-PUMP.
TABLE, containing Nineteen Sets of Experiments on Windmill Sails, of various Structures,
Positions, and Quantities of Surface.
Ratio of
Ratio of
greatest
Description of Sail
No.
made use of.
Angle at the
extremities.
Grentest
Angle.
Turns of the
Sails unloaded.
Turns of the
Sails at the
Maximum.
Load at Maxi-
mum.
Greatest Load.
Product.
Quantity of
greatest
Ratio of
Surface.
Velocity
Load to
Surface to
to the Ve-
the Load
the Pro-
locity at
at Maxi-
duct.
Maxi-
mum.
mum.
Plain sails at an an-
Deg.
Deg.
lbs.
lbs.
Sq. In.
gle of 55° with the
1
35
35
66
42
7.56
12.59
318
404
10:7
10:6
10:7.9
axis
Plain salls weather-
2
12
12
70
6.3
7.56
441
404
10:8.3
10:10.1
ed according to the
3
15
15
105
69
6.72
8.12
464
404
10:6.6
10:8.3
10:10.15
common practice.
4
18
18
96
66
7.0
9.81
462
404
10:7
10:7.1
10:10.15
Weathered accord-
5
9
261
66
7.0
462
404
10:11.4
ing to Maclaurin's
6
12
291
701
7.35
518
404
10:12.8
theorem
7
15
321
634
8.3
527
404
10:13.
8
0
15
120
93
4.75
5.31
442
404
10:7.7
10:8.9
10:11.
Salls weathered in
9
3
18
120
79
7.0
8.12
553
404
10:6.6
10:8.6
10:13.7
the Dutch manner
10
5
20
78
7.5
8.12
585
404
10:0.2
10:14.5
tried in various
11
7f
221
113
77
8.3
9.81
639
404
10:6.8
10:8.5
10:15.8
positions
12
10
25
108
73
8.69
10.37
634
404
10:6.8
10:8.4
10:15.7
13
12
27
100
66
8.41
10.94
580
404
10:6.6
10:7.7
10:14.4
Sails weathered in
14
71
221
123
75
10.65
12.59
799
505
10:6.1
10.8.5
10:15.8
the Dutch manner,
15
10
25
117
74
11.08
13.69
820
505
10:6.3
10:8.1
10:16.2
but enlarged to-
16
12
27
114
66
12.09
14.23
799
505
10:5.8
10:8.4
10:15.8
wards the extremi-
17
15
30
96
63
12.09
14.78
762
505
10:6.6
10:8.2
10:15.1
ties
8 Sails, being sectors
18
12
22
105
641
16.4
27.87
1059
854
10:6.1
10:5.9
10:12.4
of ellipses in their
19
12
22
99
64g
18.06
1165
1146
10:5.9
10:10.1
best positions
AIR-PUMP. This instrument has been much improved in form in recent times, but the principle
remains the same; its chief use being to extract the air from a vessel, whereby we are said to exhaust
it, or to produce a vacuum. The construction and operation of the Air-pump will be understood by a
reference to the cut.
This is a sectional view of the common form of the Air-pump. R is a bell-shaped glass, ves-
sel, open only at the bottom, and whose rim is ground perfectly flat, so that it may rest on every
point, on a brass plate SS, which is likewise ground to a flat surface, so that when a little hog's-lard is
rubbed upon the edge of the glass vessel, commonly called the receiver, and then the rim placed, by a
kind of circular sliding motion, upon the brass plate, no air can pass in or out of the receiver, between
its edge and the plate. Through the centre of the brass plate there is drilled an orifice A, from which
orifice there is led a pipe AB, forming a communication between the receiver R and the interior of the
cylinder BPV, which communication may be opened or closed by means of a stop-cock at G. The
cylinder or barrel BPV is furnished with a piston BP accurately fitted to the cylinder, but capable of
free motion up and down, which motion is effected by means of a piston-rod DC, which moves through
a stuffed or air-tight collar at D. The bottom of the cylinder or barrel is furnished with a valve V
opening outwards. This cylinder communicates with another BXPV, constructed and furnished in a
similar manner; and the two piston-rods are provided with
racks C at the top, the teeth of which are acted upon by those
of a neel placed between them, as may be seen in the figure.
Let us now attend to the mode of action. Suppose the stop-
5.
cock at G open, and the pistons as they are in the figure. The
piston BP being at the top, a free communication is formed
between the receiver R and the first cylinder, and the piston
Y
being pushed down past the orifice at B, the air contained in
the cylinder or barrel will be forced into less space or com-
C
pressed, and of course its elastic force increased. In conse-
C
R
quence of this increased elasticity, the valve at V will be open-
ed, and the air expelled. When the piston is lifted. this valve
will be shut by the pressure of the atmospheric air without;
thus a portion of the air which was contained in the receiver,
S
A
S
D
D
communication pipe, and barrel, has been expelled, and that
E
which remains will consequently be less dense; another stroke
B
B
P
of the piston will diminish the density still more; and this pro-
G
cess may be continued until the density be 80 diminished, that
when compressed by the descent of the piston to the bottom of
the barrel, its elastic force is only sufficient to open the valve
F
P
V. It will be easily seen, that the exhaustion of the air in the
V
V
receiver depends on the elasticity of the air; for when the pis-
ton descends and expels the air contained within the barrel, which it will do completely, if it go to the
bottom, and then in returning, the valve V being shut, a vacuum will be formed in the barrel until the
piston in its ascent passes the orifice B, when the air within the receiver will expand and fill the whole
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AIR-PUMP.
15
cavity. The operation of the second barrel and piston is precisely similar to that of the first, so that
when the one is understood, the other requires no explanation.
The degree of exhaustion will depend upon the workmanship of the pump, the number of strokes of
the piston, and the relative capacities of the receiver and barrels; but perhaps in no case can the vacuum
in the receiver be made perfect. For the purpose of determining the degree of exhaustion, a mercurial
gauge is employed, which acts on a similar principle with the common barometer. A glass tube EF,
rests in a basin of mercury F, and its upper orifice opens into the brass plate SS. When the exhaustion
of the receiver has commenced, the pressure of the air in the receiver must be less than that of the
atmosphere without. Wherefore, since the air in the receiver presses the mercury down the tube, and
the atmosphere pressing on the mercury in the basin forces it up the tube, with the greater force the
mercury will rise in the tube, and it will rise the higher according to the difference of the density, and
consequently elastic force of the air in the receiver, and that of the atmosphere.
AIR-PUMP, Kennedy's Horizontal Double Cylinder. Any modification of, or improvement in this
instrument, is a matter of interest not only to the man whose sole pursuit is science, but to all who are
engaged in studying or illustrating the simplest truths of experimental philosophy.
It is not a little extraordinary, that while nearly every species of apparatus has been improved by
modern ingenuity, the Air-pump retains the form given it by Boyle.
Probably all users of the common form have been made sensible of its want . stability and porta-
bility. These evils were sorely felt by Mr. Kennedy, while engaged during the winter of 1841 and 1842,
in lecturing in the northern part of this country. He determined, if possible, to remove them, and before
the close of the season invented, and during the following summer constructed, the subject of this article.
He employed it the succeeding winter in his course before the Delaware County Institute of Science,
where it attracted much attention. It has been in use more than three years, and having received the
unqualified approval of several impartial scientific men, and of one of the best makers of philosophical
apparatus in the country, it is now for the first time made public.
The objections that obtain against the old form arise chiefly from the upright position of the barrels
or cylinders. This necessarily throws the pinion twelve, or more, inches above the point of support.
The handle placed on the projecting axis has a constant tendency, while the operator is working the
pump, w tilt it outwards; so much so, as frequently during rapid exhaustion, to require the steadying
hand of an assistant. This leverage outwards, and the consequent instability, are especially annoying
whilst using the barometer gauge. Again, the most eligible height of table for the display of appara-
tus, by elevating the handle, renders the work of exhaustion an exceedingly laborious one, and the
perpendicular cylinders and pump-head form an inconvenient barrier between the operator and the
glass receiver, especially if the experiment is performed on the gauge-plate; a footstool but poorly com-
pensates for this height. Finally, the Air-pump, always one of the most expensive items of the labora-
tory, is rendered so, to some extent, by the cost of the double rack, pump-head, and brass columns that
support it. On each of the points named, the horizontal double cylinder pump is believed to possess
great superiority.
6.
R
S
DESCRIPTION.-In the figure, L L represent the barrels, the enlarged ends of which are let into the
board and bolted through to ensure stability. There is one rack; the two pistons being attached to its
extremities. A portion of the rack is exposed at T. The semi-pinion W, works in cast straps, or
gudgeons, attached to the bottom of the board by screws, which, passing through, terminate in the
rack guides, one of which is seen above. The forward gudgeon is 80 cast as to receive the end of the
clamp which secures the pump to the table. The semi-pinion works upwards through a slot cut in the
board, and of course between the rack guides. The upper extremities of the guides are perforated to
I sceive rollers, against which the back of the rack may work when necessary. None have yet been
required. To the axis of the semi-pinion the handle is attached in the usual manner. The piston may
be either solid or valved, and the cylinders may communicate with the plates R and B, in the wav most
approved by the maker. In the pump from which the sketch is taken, the pistons are solid. The
farther extremities of the cylinders bear female screws, which connect with corresponding male screws
on the block. On the posterior portion of each block is cut a female screw; the male of which bears
the valve V V, of course opening inwards. On those portions of the blocks which project into the
board are cut male screws bearing valves opening outwards. Perforated nuts over these secure the
blocks to the board, and the valves against injury. At V V is attached the tube leading from the
plates. D is the screw for restoring atmospheric pressure. The general stop-cock S, connects this with
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AIR-PUMP.
the parellel tube which, bearing the gauge-cock S', forms at pleasure a communication between the
plates.
The original of the figure both exhausts and condenses. The remaining letters refer to the parts used
in condensing. This is effected by simply connecting, by means of tubes under the board, the valves F',
F, with a third tube passing upward to the stop-cock K. Then the air drawn in at R, will be condensed
in a receiver screwed on C. Those familiar with Pneumatic chemistry need not be told of the facilities
thus afforded for the transfer of gases. The condensing gauge is borne by the screw G. To the working
philosopher, it is unnecessary to amplify the advantages that result from lowering the centre of motion
to a level with the points of support, bringing both plates directly under the operator's eye, and pre-
senting, at about the cost of an ordinary exhausting pump, an instrument furnished with all the facilities
for exhaustion, transfer, and condensation, without any shifting of parts-Philad, Dec. 1845.
AIR-PUMP, rules respecting,-diameter of,-rules for part of,-valves of,-canvas valves for,-side
valves for,-metallic packing for,-indicator applied to. See DIMENSIONS OF ENGINES, and MANUFACTURE
and MANAGEMENT OF ENGINES.
AIR-PUMP CROSS-HEAD, table of sizes of. See DIMENSIONS OF ENGINES.
AIR-PUMP ROD, table of sizes of,-rules for strength of. See DIMENSIONS OF ENGINES-Materials
for. See DETAILS OF ENGINES.
AIR-PUMP SIDE RODS, table of sizes of,-rules respecting passages,--area of. See DIMENSIONS OF
ENGINES.
AIR-PIPES, an invention for clearing the holds of ships and other close places of their foul air. The
contrivance is simply this: a long tube, open at both ends, is placed with one end opening into the
apartment to be ventilated, and the other out of it. The air in the outer end of the tube is rarefied by
heat, and the dense air from the hold comes in to supply the partial vacuum, the escape of the foul air
in the hold being supplied by fresh air introduced through an opening above; and this process is carried
on until the air becomes everywhere equally elastic.
AJUTAGE, a tube fitted to the mouth of a vessel for the purpose of modifying the discharge of water.
ALARM-Fire Damp. At the Academic des Sciences, at Paris, M. Chuart's invention was explained
it consists of a ball or globe, contained in a chemical solution highly sensitive to any deterioration of the
atmosphere, and acting upon a lever, which sets an index in motion, and thus shows the vitiated state
of the atmosphere, whether in a mine or elsewhere, long before the common air can be so saturated
with gas as to explode on the application of light. M. Chuart has added to his invention an alarum-
bell, which is struck by the lever when the ball is thrown off its equilibrium by the vitiated state of
the atmosphere. Since M. Chuart first exhibited his apparatus he has made a great improvement.
His ball was originally of glass, which was not only too heavy, but also liable to breakage. He now
makes it of copper, so very thin that its weight is almost nominal, and yet it is perfect in every part.
It is stated that he arrived at this perfection by means of the galvanic process, which gives a thinner
substance than any mechanical means could effect consistently with the compactness that is required
for the certain operation of the apparatus. 1845.
ALARM-WHISTLE The object of this instru-
ment is to prevent injury to boilers from the water
7.
falling below its proper level.
A is a float attached to a stem or rod, which
H
D
passes upwards through a tube, B¹, and a diaphragm,
B², fixed within that tube, and terminates in a
conical top, which fits into the hollow pipe C, of
the steam-whistle D. The lower end of the whistle
a
a
D is passed through an orifice in the top of the
boiler, (indicated by the letters a a,) and screwed
into the top of the tube, which is thus kept steady,
E
if in a vertical position. E is a collar attached to
K
K
the stem of the float, near the top, which, catching
B
against the plate B², on the fall of the stem or rod
A, prevents it from descending further. When the
water falls below the safety-line, and the float along
with it, the descent of the stem of the float opens
the pipe C of the whistle, and allows the steam to
escape, which, impinging against the bell H at top,
B
produces the alarm required. KK are orifices in
the side of the tube to facilitate the rushing of the
steam into the whistle, as soon as the boiler is in
danger.
ALDER. See Woods, varieties of.
ALLOYS. See METALS and ALLOYS.
ALLUVIAL DEPOSITES. See RAILWAY EN-
GINEERING.
ALMOND-TREE See WOODS, varieties of.
A
ALOES-WOOD. See WOODS, varieties of.
AMBOYNA-WOOD. See WOODS, varieties of.
AMERICAN STEAM EXCAVATING MA-
CHINE. This machine, which is the invention of
the late Mr. Ottis, of New York, is an application of
steam-power to the purposes of excavation and
is edging; and for the former purpose, appears
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AMERICAN STEAM EXCAVATING MACHINE.
17
12.
11.
o
"OT
S
F
13.
R
tot
9.
c
g
SCALE.-16 feet-3 inches.
greatly superior to any thing which has hitherto been achieved in excavating machinery. The ac-
companying engraving presents the principal side elevation (Fig. 8) of the machine, which brings all
the working parts sufficiently into view; Fig. 9, a plan of the horse-shoe pulley and crane top. the
3
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18
ANACLASTICS.
dotted lines show the position of the lower framing or stage and boiler; Fig. 10, shows the crunk
shaft and gearing; Fig. 11, the main drum; Fig. 12, the main drum for working the excavator; and Fig.
13, a plan of the excavator.
The whole of the details of this machine, which are very elaborate and complete, of course cannot
be attempted in an article of this nature; we will, however, describe as much of the details and its
principal feature as are necessary to a proper understanding of the several movements of the machine,
and then describe each of those movements separately. The machine consists of a strong horizontal
wooden framing or stage A, mounted upon two pairs of railway wheels b, for locomotion, which run on
temporary rails, laid down as may be required; on the one end of the stage is fixed a cylindrical boiler
C, and the gearing for turning the crane round. In the middle is placed the gearing for working one of
the motions of the excavator D; and, at the other end is placed the wooden crane E, in form similar to
an ordinary timber crane, on the diagonal brace of which is placed a platform f, on which an assistant
stands; and gearing W, for working another motion of the excavator D. To support the machine
laterally, strong brackets or arms project on either side, the ends of which are furnished with screws
to adjust the machine to the inequalities of the surface of the ground.
The excavator or shovel D, (Figs. 8 and 13,) is formed of stout boiler-plate, and is firmly riveted
together; it is of a box shape, having one end open; on the lower edge are four tangs or points,
which serve to penetrate and loosen the soil; the other end is hung on swivel hinges, and fastened by
a spring d, which may be set at liberty by means of the lever and rods a, Fig. 8.
The machine is made to periorm three distinct movements; 1st, the digging movement; 2d, the
turning movement; and 3d, the locomotive movement.
The Digging Movement consists of two motions, one for drawing the excavator forward, and the other
for driving it into the ground, both of which are done simultaneously the first motion is performed in
the following manner. On the horizontal stage A, and in front of the boiler C, is placed a small high-
pressure engine, (not shown in the engraving,) the connecting rod of which acts upon the crank c, and
gives a rotary motion to the shaft L, and with it the pinion l, (Fig. 10,) which works into the large
wheel M, mounted on the shaft N, upon which is fixed a large channelled barrel or drum n, (Figs. 8
and 11,) round which the hauling chain O, is coiled; this chain passes upwards through the hollow crane
post, over the indented pulley P, to a double pulley fixed at the jib-head, thence round the blocks R,
to which the excavator is suspended, as the chain wound up draws the excavator out of the ground
both in a forward and upward direction, when driven into the ground by the second motion. This last
motion is communicated by the chain traversing over the indented pulley P, to another gearing. On the
axle of the indented pulley P, is fixed a bevelled wheel v, (Fig. which works into a similar one v', (Fig.
8,) mounted on to the upper end of the oblique shaft V, on the lower end of which is a corresponding
bevelled wheel v", working into another 20, fixed upon the shaft W; upon this shaft is a pinion w',
which takes into the large spur wheel u', mounted upon a shaft, upon which is a channelled drum
u, round which is coiled the chain s, attached to the diagonal wooden arms S; on the lower end of
these arms is fixed an iron yoke, to which is suspended on pivots the excavator. By this arrange-
ment, as the main chain o passes over the pulley P, motion is communicated to the shaft for the
purpose of forcing downwards in a diagonal direction the arms S, and with them the excavator into the
ground. A man stands upon the stage f, for throwing in and out of gear this apparatus, and to
regulate the motion for lowering or raising the excavator.
The next motion to be described, is for the purpose of turning the crane round either to the right or
to the left; this is effected by another gearing in the following manner. On the first crank shaft I, is
fixed a bevelled wheel l, (Fig. 10,) which works into a similar wheel g, mounted on to the end of a hori-
zontal shaft G, upon which are placed loose two bevelled wheels g'g", either of which can be thrown in
or out of gear so as to work, as may be required, into the large bevelled wheel h, mounted upon the
shaft H; upon this shaft is a pinion h', which works into the wheel j, fixed on the shaft J; upon this
shaft is fixed an indented pulley j', round which the chain r is coiled, and passes upwards over pulleys 8,
round either side of the horse-shoe pulley, to the ends of which it is fixed by iron bolts; the horse-shoe
pulley is fixed by means of strong iron stays to the crane, and when it is made to revolve, the crane-jib
is turned round on the stationary post t, either to the right or to the left as may be required, and
empties the contents of the excavator into a wagon or barrow.
The Progressing Motion is effected by placing on the hind wheel axle a strong wheel, shown by a
circle b, (Fig. 8,) which communicates with a pinion b', on a shaft, as shown by a dotted circle; motion
being given to the shaft above by the bevel gearing described in the last motion, a forward or back-
ward motion of the machine is obtained.
We have no precise data as to the cost of the machine or the quantity of work that can be performed
by it, further that a rough estimate, which states that the machine is capable of digging 1000 cubic
yards of earth per day, and that a machine complete costs about 6000 dollars.
ANACLASTICS. That part of Optics which considers the refraction of light, and is commonly called
Dioptrics.
ANCHOR. A heavy curved instrument, used for retaining ships in a required position. The forms
of anchors, and the materials of which they are made, are various. In many parts of the East Indies
the lower part of the anchor is formed of a cross of a very strong and heavy kind of wood, the extrem-
ities of which are made pointed. About the middle of each arm of the cross is inserted a long bar of
the same wood, the upper ends of which converge to a point, and are secured either by ropes or an iron
hoop, and the space between the bars is filled up with stones to make the anchors sink more deeply and
readily. In Spain, and in the South Seas, anchors are sometimes formed of copper, but generally in
Europe they are made of forged iron. Anchors may be divided into two classes-mooring anchors, and
ships' anchors. Mooring anchors are those which are laid down for a permanency in docks and harbors,
and are considerably heavier than ships' anchors, from which they differ in form, having sometimes but
one arm, and sometimes, instead of arms, having at the extremity a heavy circular mass of iron and no
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ANCHOR.
19
stock; these latter are called mushroom anchors, The general form of ships' anchors is shown in the
annexed figure. There is a long bar of iron, called the shank,
from the lower extremity of which branch two curved
arms bb in opposite directions, and forming an angle of
d
60° each with the shank. Upon each arm, towards the
end, is laid a thick triangular piece of iron cc, termed the
Auke. In the upper end of the shank is an eye, through
which passes a ring d, to which the cable is attached.
The stock e is composed of two strong beams of wood,
embracing the shank immediately below the ring, and se-
cured together by iron hoops and tree-nails; the stock
stands at right angles to the plane of the arms, and serves
to guide the anchor in its descent, so as to cause one of
the flukes to enter the ground. Ships are generally pro-
vided with three large anchors, named the best bower, the
small, and the sheet anchor; a smaller anchor, termed the
14.
stream anchor; and another, still smaller, named the kedge,
which latter has generally an iron stock passing through
an eye in the shank, secured thereto by a key, or forelock,
which admits of its being readily displaced its principal
use is in changing the position of a ship in harbor, and in
an operation termed kedging. From the great mass of
iron in large anchors, (some weighing from 3 to 4 tons,)
b
the perfect forging of them becomes a matter of much dif-
b
ficulty; as from the great heat necessary to weld such mass-
es, the iron is liable to become "burnt," as it is termed.
Workmen also cannot always observe what is going on in
the forge, where the iron is exposed to ignition from the
blasts of the bellows, or to the presence of sulphur in
quantity among the coals. When the welding of a large mass, like the shank of an anchor, is to be
completed by the sledge-hammer, the workmen are subjected to a scorching heat radiating therefrom,
which renders it impossible to make a very close inspection, and the consequence frequently is, the
beating up of cinders within the body of the iron. To this cause, and to burning, may be often attrib-
uted the breaking of anchors, followed too frequently by a distressing loss of lives and property. Many
attempts have been made of late years to construct anchors not liable to these defects, by dividing the
mass into separate parts, and by a more judicious arrangement. The following is the invention of Mr.
Hawkes. He observes, "The anchors at present in
use are made by forming the shank and flukes sepa-
rately; and by the rapid action of heavy hammers,
a
they are united or welded into each other, and the
cable is fastened to a ring passed through the shank
sidewise. The stocks, if of wood, are let or scored
over each side, and bolted and hooped over the
shank of the anchor; if of iron, the eye or hold for
it is formed by punching a hole through the shank
of the anchor; the palms are made separately, and
welded on to the flukes. The improvement consists
in making one fluke and half the shank in one
length, and to bend them to the form required, and
then hooping the two halves together. This method
of making the anchor in separate parts, admits of
the forming of a groove up the middle of the shank,
for a chain to pass through, and of an eye of great
-
15.
strength for the reception of a wooden stock, which
d
is also made in two pieces, and passed into the
shank in reverse directions; these having iron
shoul ders abutting against the eye, are kept im-
move..)ly in that position by being braced to-
h
gether with an iron hoop at each end. The con-
struction is shown in the annexed engraving a the
d
cable ring b the eye which holds the stock, made
out of the whole substance of the shank, by bend-
ing each of the halves into a semicircle, in opposite
directions. The anchor is shown to be divided into
two equal parts, by a line which passes down the
middle of the shank, as at 00; c the wooden stock,
made also in two equal parts, as before described,
and firmly secured in their places by the hoops and
shoulders; dd d are four strong hoops which bind
the shank together; the upper one is made square,
and the others circular; a portion of the shank is
supposed to be removed, to exhibit the situation of the chain which passes up the centre, and is con-
nected at the upper end to the cable ring, and at the lower end to the buoy ring. f, in the small sep-
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20
ANCHOR.
arate figure, gives a transverse section of the shank of the anchor, showing it to be of an oval form, the
longest diameter of which is in a line with the flukes; this figure conferring upon it great strength to with-
stand the powerful strains to which an anchor is frequently exposed in that direction. hh are the
palms, bolted to the respective flukes, each of which is connected in one piece with a brace ii,
passing in opposite directions round the shank of the anchor, thereby strengthening the flukes in a
great degree, and giving a collateral support to each half of the anchor. k is a strong plate of iron
bolted on to the crown; 1 the buoy ring."
One differing materially in form and construction from the ordinary anchor was invented by Mr. R.
F. Hawkins, and is represented in the subjoined engravings. The shank of the anchor a is forked
at the lower part or crown, into two parts or loops b and c, in each of which is formed a hole or eye;
between the loops is a block of iron d, termed a crown-piece, having a circular aperture to receive the
arms, and a square aperture at right angles to the former, into which is screwed a stout bar of iron e,
termed a toggle, projecting equally on each side of the crown-piece; on the end of the crown-piece, op-
posite to that in which is inserted the toggle, is a ring f for the buoy rope. The arms g h are formed in
one piece, and before the palms ii are attached, one end of the arms must be passed through the eyes
in the loops of the shanks, and through the eye of the crown-piece; the palms are then to be put on, and
must both lie in the same
plane; after which the arms
are to be curved in the same
plane with the palms. The
16.
crown-piece is firmly keyed
a
to the arms, and the toggle
must be of such a length and
form as to make it bear firmly
against the fore part of the
fork in the shank, 80 as to pre-
vent the crown-piece and arms
from turning round upon it, and
to retain them at an angle of
50° with the shank. When the
anchor is let go, one end of the
toggle will come in contact
with the ground, which puts
the flukes in a position to en-
ter; and when the strain is
upon the cable, that end of the
toggle which is upwards comes in contact with the
throat of the shank, and sets the anchor in the hold-
17.
ing position, as shown in perspective at Fig. 17.
The advantage of this mode of constructing anchors
is, that both arms take the ground, and therefore
the weight of metal may be diminished, and yet
an equal, if not a greater, effect be obtained also,
as there is no stock, and no projecting upper fluke,
there is little risk of fouling, as it is termed that
is, of the cable entwining round the arms. The only objection which occurs to us, is the probability that,
when at single anchor, it might not 80 readily turn in the ground at the turn of the tide, as the ordinary
anchor, and therefore might be likely to trip; but for moorings we have no doubt that it would be found
very effective.
An anchor upon a similar principle, but of a some-
what different construction, was invented by Mr.
Soames, a front and side elevation of which is ex-
hibited in the subjoined cuts. In this anchor there is
but one fluke a, which is T-shaped, and works on a
pivot in a triangular frame, composed of the two sides b
d
a d c, forged in one piece, and a stay d, which serves
as a stock; ff are loops, or eyes, for the reception of
the chains that unite the ring g, to which the cable is
18.
to be fastened. For general purposes, this anchor is,
perhaps, preferable to the former, it being free from
the objection we made to that one, as it admits of de-
taching the arm, which renders it more convenient to
19.
stow away; also, as the shank is formed in two parts,
instead of one of equal area, they are more easily
forged soundly, and consequently less liable to break-
age.
The anchor proposed by W. Rogers is deserving of
cotice. Its main peculiarity consists in its having a
hollow shank, formed out of six bars of iron, of such a
thickness as to ensure the forging of them perfectly
sound for anchors of the largest dimensions. The con-
struction we shall describe with reference to the sub-
joined figures. Fig. 21 represents a side view of the anchor, and Fig. 20 a plan of the stock. The two
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ANCHOR.
21
principal pieces a a are bent 80 as to form a part of the arms or flukes; the other four are formed into
a hollow tube b b (as shown in section at Fig. 22) for a centre-piece, and the whole are firmly welded
together at both ends of the shank. The intermediate parts are secured by strong hoops i i, 80 that
every piece must bear its proportion of the entire strain. In place of the usual ring, there is a bolt
and shackle c, Figs. 21 and 23, when the anchor is to be used with chain cables; but when hempen cables
are to be used, a ring d is connected to the shackle c by an additional shackle and bolt e. The anchor-
23.
22.
do
b
6
21.
a
20.
stock f may be formed either of a single piece, or of two pieces hooped together, and is secured in its
place as follows: The bolt and shackle c being withdrawn, the small end of the shank is passed
through the eye of the stock f, (which is defended by an iron plate g on each side ;) the collar h is then
put over, and the stock is keyed up against the hoop i by the forelock key k passing through a hole in
the shank; by this means the anchor may be stocked or unstocked without the assistance of a carpenter,
which is a great recommendation, as a considerable length of time is required to stock an anchor in the
common way. These anchors have been pretty extensively adopted, and several parties who have
made trial of them have given satisfactory certificates of their efficiency. In connection with improve-
ments on anchors, it may not be altogether out of place to mention some improvements in the method
of letting them go.
Two improved methods of letting go anchors are described in the Transactions of the Society of Arts.
The principle is the same in each, and consists in supporting the end of what is termed the standing
part of the cat-head stopper and shank-painter, by bolts turning upon pivots, and retained in a proper
position by a catch, which being withdrawn, the bolt turns upon its pivot, and the stopper slips off, by
which means all risk of jamming the turns of the stopper (as in the common method of letting go the
running end) is avoided; the danger to the men on the forecastle is done away, and the anchor can be
let go at a moment's warning.
The arrangements in each of these inventions being the same, whether applied to cat-head stoppers
or shank-painters, we shall therefore
show one invention as applied to
cat-head stoppers, and the other to
l
a
shank-painters. The subjoined cuts
show Capt. Burton's method of letting
B
go a cat-head stopper. a i the cat-
head; bc a bolt, turning .pon a
pivot d; the end c forms an oblique
plane, and is held down by the
clamp e turning upon a pivot f, the
clamp being secured by a hasp g and
pin h. The standing end of the
stopper, having an eye formed in it,
passes over the end b of the bolt
bc; the other end of the stopper
25.
94.
passes through the ring of the anchor,
and over the thumb-cleat k, and is
made fast round the timber-head 1.
When it is required to let go the
anchor, a handspike is inserted be-
tween the thumb-cleat k, 80 as to nip
the clamp e, and the hasp g is cast off; then, upon withdrawing the handspike, the bolt being no longer
held by the clamp e, turns upon its pivot d, by the weight of the anchor on the stopper, and the eye of
the stopper slips off the end of the bolt.
The following cut represents Mr. Spence's invention for letting go a shank-painter. Fig. 26 is an
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22
ANGICA-WOOD.
elevation, and Fig. 27 the plan. a is a cast-iron carriage, bolted through the ship's side, and supporting
the hook d by a pin or pivot at b; d e a lever turning upon a centre f, the end d being formed into a
hook, which clasps the upper end of the bolt b, the lever being retained in the position shown in the
plan, by a pin g h is part of a chain forming the standing part of the shank-painter, and supported by
the bolt b. To the other end of the chain is spliced
the running part of the shank-painter, which passes
round the shank of the anchor, and is made fast to a
26. d
b
e
timber-head. When it is required to let go the
a
shank-painter, an iron bar is inserted into the end B
of the lever d e, which is made hollow for the pur-
pose, and the pin g being withdrawn, the lever is
turned round its centre until the bolt is released from
the hook d, when it falls, and the chain end of the
shank-painter slips off.
a
ANGICA-WOOD. See WOODS, Varieties of.
ANEMOMETER. An instrument for measuring
27.
b
the strength or velocity of the wind. Among various
machines which have been constructed for this pur-
pose, the following one has been found to answer very well. It consists of an open frame a c, sup-
ported by a shaft d, upon which it turns by the action of the wind upon the vane e. f f are sails, fixed
to one end of the axis g, and disposed to be influenced by the wind in the usual manner. Upon this
axis is also fixed a conical barrel of wood h k, on the smaller end of which k is attached a line l, with a
weight appended to it. The wind acting upon the sails, causes the barrel to revolve, and the line to be
wound up on its superficies. To prevent any retrograde motion, a ratchet wheel o is fixed to the base or
larger end of the cone, having a clicker falling into the
notches as it revolves. It is evident that the power of
the weight will continually increase as the line advances
towards the base of the cone, as the weight acts at a
f
greater distance from the axis or fulcrum; conse-
quently, the variable force of the wind may be readily
ascertained by fixing the line at the smallest end, and
marking the barrel with spiral lines, as taken up by
the coiling of the rope round its superficies, placing
g
og
also between the lines numerals to denote the force of
the wind, which may be calculated with tolerable
precision upon the principles of the lever. The
c
a
diameter of the cone should be such in comparison
with its smallest end, that the force of the strongest
wind should have scarcely sufficient force to bring the
line on to the base of the cone.
Although the instrument de-
29.
scribed above gives an accurate
idea of the comparative force of
28.
the wind at different times, it
does not point out the actual
force exerted on a given surface,
3
nor can observations made with
h.
one instrument in a particular
place, be compared with obser-
2
1
vations made by another instru-
k
ment elsewhere. It is also cum-
bersome, and not portable. In
1
m
d
the Philosophical Transactions
for 1775, Dr. Lind gives a de-
scription of a very ingenious
AWY
portable wind gauge, which indi-
cates the actual force of the wind
g
by the column of water which it will support. This instrument consists of two glass
1
tubes a b, c d, which should not be less than 8 or 9 inches long, the bore of each being
about four-tenths of an inch in diameter, and connected together by a small bent glass
tube e, of about only one-ninth of an inch bore, to check the undulations of the
3
water caused by a sudden gust of wind. On the upper end of the tube a b is fitted
6
a thin metal tube f, which is bent at right angles, and has its mouth open to re-
ceive the wind blowing into it horizontally. The two branches of the tube are at
liberty to turn round a steel spindle g, which passes through two slips of brass h i
i
near the top and bottom of the instrument. The spindle is fixed into a block of
wood by a screw in its bottom. When the instrument is used, a quantity of water
is poured in until the tubes are about half full, and the instrument being then
held perpendicularly, with its mouth exposed to the wind, the water will be de-
pressed in the tube a b, and proportionably elevated in the tube cd; and the dis-
tance between the surfaces in the two tubes measured by a sliding scale of inches,
and parts k attached to the instrument, will be the height of a column of water
which the wind is capable of sustaining at that time; and as a cubic foot of water
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ANNEALING.
23
weighs 1000 ounces, or 621 pounds nearly, the
Height of Water.
Force of Wind.
twelfth part of which is 5 5-24 pounds, therefore
Velocity
per
Hour.
Inches.
lbs.
Miles.
every inch the surface of the water is raised, the
t
1.3
18
force of the wind will be equal to 80 many times
Mr
2.6
25.6
5 5-24 pounds on the square foot. This instrument
1
5.2
86
shows the force, but not the velocity, of the wind;
2
10.4
50
but as the force is as the square of the velocity, if
8
15.6
62
the velocity due to a given force be ascertained, a
4
20.8
76
table of the velocities corresponding to each inch
5
26.
80.4
the water is elevated, may be calculated and en-
6
31.25
88
graved upon the scale of equal parts. The table
7
36.5
95.2
at the right, showing the corresponding height of
8
41.7
101.6
water, velocity of the wind, and the force exerted
9
46.9
108
upon a square foot of surface, has been calculated
10
52.1
113.6
from some experiments made by Dr. Hutton.
11
57.3
119.2
ANNEALING. The process by which metallic,
12
62.5
124.
and other mineral productions, are converted from
a brittle to a comparatively tough quality, presumed to bè caused by a new arrangement of their con-
stituent particles. In a considerable number of bodies that will bear ignition, it is found that sudden
cooling renders them hard and brittle, while, on the contrary, if they are allowed to cool very gradually,
they become softened or annealed. We have, however, noticed several alloys of copper (brass in
particular) in which sudden cooling has the reverse effect, that of annealing it. The process of anneal-
ing requires some address and experience to perform it in the best manner; and varies in the degree of
heat applied, as well as in the period of cooling, according to the nature of the metal or other substance
operated upon. In the annealing of steel and iron, the metal is heated to a low redness, and suffered
to be gradually reduced in its temperature, covered up, on a hearth. Ovens are constructed for this
purpose, wherein the pieces of metal, according to their massiveness, and the quality it is desired they
should possess, are placed and retained at a low heat for days, and sometimes weeks together. The
annealing of glass is performed precisely in the same manner.
ANGLE IRON HOOP, tables of circumferences, for facilitating construction of boilers. See
DIMENSIONS OF ENGINES.
ANGLE AND SURFACE JOINTS. See JOINING AND WORKING SHEET METAL.
ANGLE OF FRICTION. See FRICTION AND RIGIDITY.
ANGLE, to be given to double-lock gates. See LOCKS OF CANALS AND RIVERS.
ANGLES AND POSITIONS OF TOOLS, as regards the act of cutting. See CUTTING Tools,
general remarks upon.
ANGLES. See TURNING TOOLS.
ANGULAR THREAD SCREWS. See SCREW-CUTTING TOOLS.
ANGLE, in Geometry, means nearly the same thing with the word inclination; thus, if two lines
drawn on a plane surface are 80 situated that they meet in a point, or would do so, if long enough, they
form an opening which is called an angle. The point where the lines which form the angle meet, is
called the angular point; and if on this point as a centre, the one point of a compass be placed, while
the other is made to describe the arc of a circle, which passes through both of the lines that form the
angle, that arc will be the measure of the angle. It is to be observed, however, that it is not the length
of the are which determines the magnitude of the angle, but the number of degrees, minutes, and
seconds conta in it, 80 that if the arc consists of 20° 80', the angle is said to be one of 20° 30'.
Angles are of various kinds, as Right, Obtuse, and Acute. When one line meets another, or stands
upon it, and makes the angles on both sides equal to each other, then these angles are each called a
right angle, and in this case the one line is said to be perpendicular to the other. In the common
language of workmen, the one line is said to be square with the other and if the one line be horizontal
the perpendicular is said to be plumb to it. The arc which measures a right angle, is the quarter of the
whole circumference, or is a quadrant, and contains 90 degrees; any angle measured by an arc less
than this, is said to be acute, (sharp,) and if the arc which measures the angle be greater than a quad-
rant, the angle is said to be obtuse, (blunt.)
The measurement and formation of angles is of extensive application in the mechanical arts, and it
is therefore necessary that the artificer should be familiar with the subject. On this account we will
introduce in another place an explanation of the various lines employed for that purpose, which lines,
however, are more frequently treated of under the head of Trigonometry.
ANIMAL KINGDOM, materials from-used in the mechanical and ornamental arts.
Porcelanous and nacreous shells, bones, etc.-The hard solid substances derived from the Animal King-
dom, are parts of the external or internal skeletons, as shells and bones or of the instruments of sus-
tenance and defence, as horns, hoofs, nails, claws, and teeth these, together with the various coverings
of animals, whether hair, feathers, or scales, are alike composed of animal and earthy matters, almost
exclusively albumen, gelatine, and lime, combined in various proportions, and with a structure more or
less interspersed with animal fibre. Many of these are either formed by the deposition of successive.
annual layers, or they are altogether yearly renewed.
A brief consideration of the chemical difference between their component parts, and of their respective
proportions, in such as are used in the arts, will show the reasons for their various characters, and differ-
ent treatment with tools.
Albumen, the principal ingredient of these animal substances, and which exists in the purest form in
the white of eggs, is hardened by a degree of heat less than the boiling temperature of water, and is
msolulde in the same. Gelatine, of which jelly and glue are different examples, is softened by heat, and
rendered fluid by the addition of water: both are easily cut and scraped, in all their various stages from
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ANIMAL MATTER USED IN THE ARTS.
soft to hard, and during this change they contract very materially, but without entirely losing their elas-
ticity.
The earthy matters of the animal solids, principally the phosphate and carbonate of lime, are widely
different from the foregoing, and also from the substances of the woods and metals. They are inelastic,
and often crystalline, and therefore incapable of being cut into shreds or shavings; as when they are
divided, they become smaller fragments or particles which are always angular: they are comparatively
uninfluenced by water or small changes of temperature, and are incapable of contraction.
When the earthy and crystalline structures prevail, the animal substances are harsh, incapable of ab-
sorbing moisture, or of alteration of size or form; when the animal and fibrous characters prevail, they
are easily cut, and they absorb moisture, soften, and swell. Enamel of teeth, the hardest of the class,
contains from 2 to 31 per cent of animal matter, (Berzelius.) Porcelanous shells are nearly similar.
Nacreous shells, 24 per cent, (Hatchett.) Ivory, 24 per cent, (Ure;) 25 per cent, (Merat Guillot.)
Bone, 33 per cent, (Berzelius.) Horn, is coagulated albumen and lime, with 1 per cent of phosphate of
lime, (Ure.) Tortoiseshell is nearly the same as horn. The horn of the buck and hart are intermediate
between bone and ordinary horn, (Ure.)
In some of the shells, the quantity of animal matter is so small, and the lime is in 80 hard and compact
a form, that they are very brittle, partially translucent, generally they have smooth surfaces, and are in-
capable of being cut with a knife or tools; such shells are called porcelanous, from their resemblance to
porcelain, they include most of the univalve shells, such as the whelks, limpets, and cowries. Most of
these can only be worked upon after the manner of the lapidary, with emery and other gritty matters
harder than themselves, by which means they are cut and polished, as will be explained in speaking of
that art; by analysis, porcelanous shells are considered closely to agree with the enamel of the teeth.
The nacreous shells, thus named from nacre, the French for mother-of-pearl, are most commonly known
in the shells of the pearl-bearing oyster of the Indian Seas, (Ostræa margaritifera,) but they include the
generality of the bivalve shells, as the various oysters, muscles, &c. within they are smooth and iridescent,
without they have a rough coat or epidermis.
These kinds contain a larger proportion of animal matter, which is considered to be arranged in alter-
nate layers with the carbonate of lime; and as these shells also are impenetrable to water, they neither
shrink nor swell. The pearl shells are less frangible and hard than the porcelanous shells, and they ad-
mit of being sawn, scraped, and filed, with ordinary tools; but they are harsh, scratchy, and disagreeble
under the operation.
The beautiful iridescent appearance of the pearl shells is attributed to their laminated structure, which
disposes their surfaces in minute furrows, that decompose and reflect the light; and owing to this lamel-
lar structure, they also admit of being split into leaves, for the handles of knives, counters, and the pur-
poses of inlaying. As the pieces are very apt to follow, and even to exceed the curvature of the surface,
splitting is not much resorted to, but the different parts of the shell are selected to suit the several
purposes as nearly as possible; and the excess of thickness is removed upon the grindstone in preference
to risking the loss of both parts in the attempt to split them.
The usual course in preparing the rough pearl shell for the arts, is to cut out the square and angular
pieces with the ordinary brass-back saw, and the circular pieces, such as those for buttons, with the an-
nular or crown saw, fixed upon a lathe mandrel. The sides of the pieces are then ground flat upon a
wet grindstone, the edge of which is turned with several grooves, as the ridges are considered to cut more
quickly than the entire surface, from becoming less clogged with the particles ground off. The pieces
are finished upon the flat side of the stone, and are then ready for inlaying, engraving, and polishing,
according to the purposes for which they are intended. Cylindrical pieces are cut out of the thick part
of the shell, near the joint or hinge, and rounded upon the grindstone, ready for the lathe, in which they
may be turned with the ordinary tools used for ivory and the hard woods.
The following are considered by an experienced dealer to be the respective qualities of the pearl shells.
Th , Chinese, from Manilla, are the best; they are fine, large, and very brilliant, with yellow edges.
Singapore, fine large shells, dead-white. Bombay, a common article. Valparaiso, also common, with
jet-black edges. South Sea pearl shells, common, with white edges.
The very beautiful dark-green pearl shells, are known as ear-shells or sea-ears; they are unlike the
others in form, being more concave, and with small holes around the margin, and are the coverings of
the Haliotis, found in the Californian, South African, and East Indian Seas. Cameos are cut in the conch-
shell, Strombus Gigas, of the southern coast of America, and the West Indian Islands.
Mr. E. H. Bond states that he has seen the Chinese work the largest of known shells, the
Chama Gigas of Linnæus, the Tridacna Gigas of Lamarck, intò snuff-bottles, tops of walking-sticks,
bangles, (a kind of bracelet,) and similar articles, some of which he possesses. The shell is a bivalve and
not nacreous, generally white, sometimes pale blue; it may be beautifully polished, and is less readily
scratched than mother-of-pearl; its localities are the Indian Seas, New Holland and the Red Sea, but the
largest are obtained from Sumatra, one pair from whence, described in Sir Joseph Banks' MSS. Library,
is said to weigh, the one valve 285, the other 222 pounds, but the more usual weight is about 100 pounds
each/valve. Mr. Bond considers the useful portions of the shell, already prepared, might be obtained
from China.
In the bones of animals, the earthy and animal matters are more nearly balanced they are therefore
less brittle than the shells, but prior to being used they require the oil with which they are largely im-
pregnated to be extracted by boiling them in water, and bleaching them in the sun, or otherwise. This
process of boiling, in place of softening, robs them of part of their gelatine, and therefore of part of their
elasticity and contractibility likewise; they become more brittle, and having a fibrous structure, they
break in splinters.
The forms of the bones are altogether unfavorable to their extensive or ornamental employment;
most of them are very thin and curved, contain large cellular cavities for marrow, are are interspersed
with vessels that are visible after they are worked up into brushes, spoons, and articles of common
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turnery. The buttock and shin bones of the ox and calf, are almost the only kinds used. To whiten the
finished works, they are soaked in turpentine for a day, boiled in water for about an hour, and then
polished with whiting and water.
Bone is far less disagreeable under the tools than the pearl shell, but it is nevertheless hard, harsh, and
chalky; the screws cut on bone are imperfect and soon injured. It is harder, often whiter, but much
less pleasant to work than ivory, which beautiful material will be treated of separately.
Horn.-In the English language we have only one word to express two quite different substances;
namely, the branched bony horns of the stag genus, and the simple laminated horns of the ox genus, and
other kindred genera.
The bony horns are called in the French bois, from their likeness to the branch of a tree; they are
annually renewed.
The other sort of horn, to which the French appropriate the term corne, and which is the subject of
our present inquiry, is found on the ox, the antelope, the goat, and sheep kinds.
These two kinds will be considered separately.
The stag-horn closely resembles the ordinary solid bones, both in its chemical characters, and also in
structure, as it is spongy and cellular in its central parts. The horn is sawn into pieces, filed to the re-
quired shapes, and used without any further preparation, the natural rough exterior of the horn being
left in the original state; its appearance is neat and ornamental, and from its uneven surface is very
suitable for the handles of knives, and other instruments requiring to be held with a firm grasp.
When short pieces of stag-horn are used entire, as for the handles of table-knives, the hollow cellular
part is concealed by the addition of the metal cap, and those parts of the white internal substance, which
are necessarily exposed, are browned with a hot iron, or the flame of a blowpipe, so as nearly to match
the other parts.
The horns of the OX tribe are deposited in annual layers upon the bony cores that project from the
foreheads of the animals; whence it results, that the general form of the horn, (neglecting its curvature,)
is conical, the portion beyond the core is solid, and the other extremity tapers off 80 as to terminate at
the base in a single plate, or extremely thin edge.
Horn consists almost entirely of animal matter, chiefly membranous-namely, coagulated albumen with
a little gelatine, and an inconsiderable portion of phosphate of lime; had the horns much more earth they
would be brittle like bones, had they much more gelatine they would be soluble like jelly or glue; as
they are constituted, the quantity of gelatine is only sufficient to allow them to be considerably softened
by a degree of heat not exceeding that of melted lead, after which they may be cut open with knives or
shears, flattened into plates, divided into leaves, and struck between dies like metal. Their gelatine
serves as a natural solder, 80 that neighboring surfaces, when perfectly free from greasy matter, may be
permanently joined together by moisture, heat, and pressure the union becomes perfect, but horn being
a cheap material, the process of joining it is seldom practised.
The straight conical horn of the rhinoceros is also occasionally used; it is solid, and formed as of a
group of hairs cemented together: the transverse section of the upper part of the horn exhibits small dots.
The horns of the chamois and antelope, and those of some other animals, are generally looked upon as
natural curiosities, and are only polished exteriorly, without any strictly manufacturing process being
applied to them.
The first step in operating upon horn is the separation of the bony core, which is effected by macera-
ting the horns in water for about a month, when, from the putrefaction of the intermediate membrane,
the core may be readily detached; this is not thrown away, but burnt to constitute the bone earth used
for the cupels for assaying gold and silver.
The solid portion or tip of the horn is usually sawn off, and the remainder, if not cut into short lengths,
is softened by immersion for half an hour in boiling water it is then held in the flame of a coal or wood
fire, until it acquires nearly the heat of melted lead, when it becomes exceedingly soft, after which it is
slit up the side with a strong pointed knife, and opened out by means of two pairs of pincers applied to
the edges of the slit; and lastly, the flats" are inserted between iron plates previously heated and
greased, which are squeezed tight in a kind of horizontal frame or press by means of wedges; wooden
boards may be used.
For general purposes, as for combs, the pressure should be moderate, otherwise, in the language of
the workman, it breaks the grain, or divides the laminæ, and causes the points of the teeth to split; but
great pressure is purposely used in the manufacture of the leaves for lanterns, which are afterwards
completely separated with a round-pointed knife, scraped, and polished. The heat and pressure when
applied to the light-colored horn render it almost transparent.
An improved mode of opening horn" was invented by Mr. J. James, by which the risk of its being
scorched or frizzled over the open fire is entirely removed; he employs a solid block of iron with a
conical hole, and an iron conical plug: these are heated over a stove to the temperature of melted lead,
and the horn, after having been divided lengthwise with a saw or knife, is inserted in the hole, the
plug is gradually driven in with a mallet, and in the space of about a minute the horn is softened and
ready for being opened in the usual manner.
In making drinking-horns, and some few other turned works, the material is cut to the appropriate
length, brought to the circular form, and allowed to cool in the mould the process is similar to that
just described, although the old methods of the open fire and wooden cones are commonly used. The
horn is then fixed in the lathe by its larger end, and turned on its inner and outer surface, and the
groove, or chime for the bottom, is cut with an appropriate tool. A thin plate, previously cut out of a
flat piece of horn with a crown-saw, is dropped into the horn, and forced into the groove, after the horn
has been sufficiently heated before the fire to allow the necessary expansion; in cooling, the contraction
fixes the bottom water-tight.
As an illustration of the peculiar properties of horn, and a mode of its employment in the lathe, may
be mentioned the expanding snake: this toy is well known to consist of a conical piece of horn, the
4
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ANIMAL MATTER USED IN THE ARTS.
one end of which is carved to represent the head, and the remainder is cut into a single spiral shred, 80
as to admit of great expansion, in imitation of the body of the reptile. I find the elastic portion of the
one before me to measure, when compressed, barely one inch and a quarter in length, and that it expands
to upwards of three feet and a half, or thirty-five times: no mean proof of the elasticity of the
material.
In making this trifle, the material is first turned to a conical form, after which a hole of about one-
eighth or one-sixth of an inch diameter, is pierced from the tail almost through the head; the horn is
then soaked for about two days in cold water to soften it, and the spiral incision or screw is made at
one single cut, by means of a tool extending from the centre to the circumference; the cutter is not
required to be very thin, as the shaving will bend away to make room for the same. One of the three
following modes of proceeding is recommended in the Manuel du Tourneur.
First, by the employment of a sliding rest, adapted to cutting screws, by which the tool is traversed,
or guided mechanically along the horn during the rotation of the mandrel of the lathe; and to prevent
the fracture of the toy during its construction, a stick of wood, with a button on the end of it, is put up
the aperture, to receive and support the spiral as it is produced.
Another method is by the employment of a lathe with a traversing or screw-cutting mandrel, upon
which latter the horn is fixed, the tool being kept stationary in the slide-rest. Both methods require
expensive apparatus, the principles of which will be explained in the article on screw-cutting tools.
The third plan is extremely simple; and appears, on inspection, to have been the one pursued in
this instance it is ascribed to the German toy-makers. The horn is prepared as before, but the lathe
and slide-rest give way to the ordinary carpenter's brace, which carries the piece of horn, as in Fig. 30. A
0
30.
mmm
32.
31.
small tool is fixed in the vice or bench; it consists of a piece of wood, to which is screwed a hardened
steel plate about one-twelfth of an inch thick it has a hole equal to the diameter of that in the horn, for
the passage of the supporting wire; the plate is divided radially, the one edge is sharpened very
keenly, and bent so much in advance of the other, that their difference of level or agreement, shall be
equal to the intended thickness of the continuous shaving of the body of the snake, and therefore the
projecting edge assimilates to the mouth of a plane: the last processes, in every case, being to carve
the head and to attach a little piece for the end of the tail.
It is necessary the coils of the snake should be of a conical form, or dished, as in Fig. 31, instead of being
quite flat, as it increases the strength of the toy this is accomplished by making the cutting edge of
the tool oblique to the axis of the snake; Fig. 32 shows the tool for the lathe. The several details are
too simple to require further explanation.
The handles for knives, razors, and other works moulded in horn, are thus made: the horn is first cut
into appropriate pieces with the saw, and when heated these are pared with a knife or spokeshave, to
the general form and size required in this state horn works as easily as a piece of deal after having
been pared, the pieces are pressed into moulds.
An idea of the moulds will be conveyed by imagining two dies, or pieces of metal, parallel on their
outer surfaces, and with a cavity sunk entirely in the one, or partly in each, according to circumstances
the cavities made either straight, curved, twisted, rounded, bevelled, or engraved with any particular
device, according to the pattern of the work to be produced.
The pressure is applied to the dies, by enclosing them in a kind of clamp, made like a very strong
pair of nut-crackers, but with a powerful screw at the end opposite to the joint; the mould, dies, and
horn, are dipped into boiling water for a few minutes, and then screwed as fast as possible immediately
on removal from the same, and in about twenty minutes the work is ready for finishing some handles
are made of two pieces joined together.
On referring to French authorities, I find it stated that horn, steeped for a week in a liquor, the active
ingredient of which is caustic fixed alkali, becomes so soft that it may be easily moulded into any
required shape. Horn shavings subjected to the same process become semi-gelatinous, and may be
pressed in a mould in the form of snuff-boxes and other articles. Horn, however, 80 treated, becomes
hard and very brittle, probably in consequence of its laminated structure being obliterated by the
joint action of the alkali and strong pressure.
Horn is easily dyed by boiling it in infusions of various colored ingredients, as we see in the horn
lanterns made in China. In Europe it is chiefly colored of a rich red-brown, to imitate tortoiseshell, for
combs and inlaid-work. The usual mode of effecting this is to mix together pearlash, quicklime, and
litharge, with a sufficient quantity of water and a little pounded dragon's blood, and boil them together
for half an hour. The compound is then to be applied hot on the parts that are required to be colored,
and is to remain on the surface till the color has struck on those parts where a deeper tinge is required,
the composition is to be applied a second time. This process is nearly the same as that employed for
giving a brown or black color to white hair; and depends on the combination of the sulphur, (which is
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ANIMAL MATTER USED IN THE ARTS.
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an essential ingredient in albumen,) with the lead dissolved in the alkali, and thus introduced into the
substance of the horn. The horn which is naturally black is less brittle than that which is so stained.
Tortoiscshell comes next under consideration. The animal which produces this beautiful substance
is a marine tortoise, called the Testudo imbricata, or hawk's-bill turtle.
The usual size of the full-grown animal is about a yard long and three quarters of a yard wide; its
covering consists of thirteen principal plates, five down the centre of the back, and four on each side, and
in a tortoise of the above size, the largest, or main-plates, weigh about nine ounces, and measure about
thirteen by eight inches, and one quarter of an inch thick at the central parts; but they are thinned
away at the edges where they overlap, owing to the deposition of the substance of the shell in annual
layers, each extending beyond the previous one. Very rarely, the shells are three-eighths thick and
proportionately heavy. Others are very thin, and appear to consist of only one single layer; this is
supposed to occur when the animal loses a plate by accident, or that it is stripped and thrown back
again into the sea whilst alive; such shells are usually very light-colored and are called yellow belly."
There are also twenty-five small pieces of shell which envelop the edge of the animal, but these can
only be applied to very small purposes.
Some of the tortoiseshell is of very dark-brown tints running into black, and interspersed with light
gold-colored dashes and marks, these are considered the best; others are lighter, even to pale red-
browns, yellow, and white: the last are not valued, the yellow are used for covering the works of
musical snuff-boxes, and the light red and brown shells are manufactured into ladies' combs, for expor-
tation to Spain, where they obtain double the price of those made of the darker colored tortoiseshell.
The shell of the turtle is also used, but it has not the transparent character of the foregoing; the colors
are lighter, less beautifully marked, and it is little valued.
The treatment of tortoiseshell is essentially the same as that of horn, but on account of its very much
greater expense, it is economized so far as possible. Before the shells are worked they are often dipped
in boiling water to temper them; three or four minutes commonly suffice, but they require a longer
period when they are either thicker or more brittle than usual: excess of boiling spoils the colors of the
shells, renders them darker, and covers the outside with an opaque white film. Others, flatten and
temper the shells with hot irons, such as are used by laundresses: the shell is continually dipped in cold
water to prevent its being scorched; but as a general rule the less tortoiseshell is subjected to heat, or to
being pulled about, the better, as from its apparent want of grain or fibre, it becomes in consequence
very brittle.
Many of the works in tortoiseshell are made, partly by cutting them out of the shell, and partly by
joining or adhesion, called by the French souder. Thus in the Manuel du Tourneur, the artist is
directed to form the ring of tortoiseshell for the rebate of a box, by cutting out a long narrow slip of
the shell; the ends are then to be filed with a clean rough file to thin feather edges, to the extent of
three quarters of an inch of their length, the one on the upper and the other on the lower surface, to
constitute the lap or joint; the slip is dipped into boiling water, and when softened it is bent into an
oval form with the intended joint on the flat side, the ends are held in firm and accurate contact with
the finger and thumb, and the piece is dipped into cold water to make it retain the form.
A pair of tongs is required, such as those in Fig. 33, with flat ends measuring about one inch wide
and three or four long, and that spring open when left to themselves, but fit perfectly close and even,
when compressed; these are made warm. In
the mean time the ends of the ring are sprung
33.
asunder sidewise, to bring the scarfs or parts to
be joined to the inner and outer surfaces respec-
tively, that they may be retouched with the file
to remove any small portion of grease which may
have been accidentally picked up, and the joint
is restored to its proper position. A piece of
clean linen is then soaked in clean water,
squeezed dry with the fingers, folded in ten to
twenty thicknesses, to about the size of one and a
half inch wide, and three or four long; the ends
are now folded together, placed on each side the joint, the whole is inserted between the tongs, and
fixed moderately tight in the jaws of an ordinary vice. The softening and consequent adhesion of the
shell, will be known by the flexibility of the ring when the loose part is wriggled about with the fingers;
the work is either allowed to cool in the vice, or after a time is dipped into cold water.
The success of the process will depend on three different circumstances; the parts to be joined must
be entirely free from "grease and dirt, on which account the surfaces should not be touched after being
filed; the temperature of the tongs should be just sufficient to color writing-paper of a pale orange
tint; and moisture or vapor must be present, apparently to liquefy the gelatine of the tortoiseshell at
the surfaces of union.
The ring, when cold, is pressed with the fingers into the circular form or even into an oval in the
opposite direction, which would cause the ends of the joints to start, if the soldering were imperfectly
performed; should this happen, the application of the moistened rag and heated tongs must be repeated
until the result is perfect; the ring is made circular by warming it in boiling water, and gently forcing
it on a wooden cone of small angle.
Another mode, the invention of an amateur, is also described; the strip of shell is chamfered off at the
ends and bent round a piece of wood, a compress of linen in six or eight folds is put upon the joint, and
the whole is tightly bound round with string, and immersed in boiling water for ten minutes. The
contraction of the string, and the expansion of the wood, from being wetted, supply the needful pressure,
and the process is said to be quite successful.
Moulding and soldering tortoiseshell, are also performed under water in various other ways; for
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ANIMAL MATTER USED IN THE ARTS.
example, in attaching the back of a large comb, to that piece which is formed into the teeth, the two
parts are filed to correspond, they are surrounded by pieces of linen and inserted between metal
moulds, connected at their extremities by metal screws and nuts; the interval between the halves of
the mould, being occasionally curved to the sweep required in the comb. Sometimes also the outer
faces of the mould are curved to the particular form of those combs in which the back is curled round,
so as to form an angle with the teeth; the joint when properly done cannot be detected either by the
want of transparency or polish at the part.
Considerable ingenuity is shown in turning to economical account the flexibility of tortoiseshell in its
heated state; for example, the teeth of the larger description of combs are parted, or cut one out of the
other with a thin frame-saw, when the shell equal in size to two combs with their teeth interlaced as in
Fig. 34, is bent like an arch in the direction of the length of the teeth as in Fig. 35. The shell is then
flattened, the points are separated with
a narrow chisel or pricker, and the two
36.
34.
combs are finished whilst flat, with
coarse single-cut files, and triangular
serapers; and lastly they are warmed,
and bent on the knee over a wooden
mould, by means of a strap passed
37.
round the foot, in the manner a shoe-
maker fixes the' shoe-last. Smaller
combs of horn and tortoiseshell are
38.
parted whilst flat, by an ingenious
35.
machine, invented by Mr. Kelly. It has
two chisel-formed cutters placed ob-
liquely, 80 that every cut produces one
tooth, the repetition of which com-
pletes the formation of the comb. Ivory and boxwood combs cannot be thus parted; they are cut in
the old way, one tooth at a time, by various contrivances of double saws, as will be explained.
In making the frames for eye-glasses and spectacles, the apertures for the glasses were formerly cut
out to the circular form, with a tool something like a carpenter's centre-bit, or with a crown-saw in the
lathe; the disks were in either case preserved, to be used for inlaying in the tops of boxes, and the
outside of the frame was then shaped with saws and files. This required a piece of tortoiseshell of the
entire size of the front of the spectacles, but a piece of a third that width is made to answer for inferior
spectacles, as the eyes are strained, or pulled. A long narrow piece of the material is cut out, and two
alits are made in it with a thin saw; the shell is then warmed, the apertures are pulled open, and
fashioned upon a taper triblet of the appropriate shape: Figs. 36, 37, and 38, explain this method; the
groove for the edge of the glass is cut with a small circular cutter, or sharp-edged saw, about three-
eighths or half inch diameter, and the glass is sprung in when the frame is expanded by heat.
Tortoiseshell is also manufactured into boxes and a variety of moulded works, but the process calls for
extensive preparations, and is not often followed by the amateur.
The construction of tortoiseshell boxes requires a copper, with a fireplace beneath; a trough with cold
water; and a press and moulds. The former may be compared to the ordinary coining press, or to a
strong rectangular frame, usually of wrought-iron, with a screw in the centre of the upper cross-piece;
the base of the press is fitted into a square recess in the centre of the bench, fixed so firmly to the floor
or wall. as to resist the efforts of two or
39.
three men at the end of a lever five or six
feet long, whose entire force is sometimes
required in tightening the mould. For the
convenience of transferring the heavy press,
a
from the hole in the bench to the hot or cold
water, a crane, the centre of which is equally
distant from the three, is added to the estab-
c
lishment.
41.
The mould required for a round box con-
sists of a thick wrought-iron ring a a, Fig. 39,
a
turned interiorly to the diameter of the box;
a
40.
it stands loosely upon a plate b; it is ac-
curately fitted with several pieces, common-
ly of brass, as c the bottom die, d the top
b
die for a plain box, e a plain block for flat
plates, and f a die engraved with any par-
ticular device to be impressed upon the
work.
e
In the Manuel du Tourneur the methods
of making four different kinds of boxes are
minutely given. Thus in the Boites d
feuilles, the best kind, in which the cover
and bottom part are each made out of a
single leaf of shell the circular pieces are to
be cut out of the shell as much larger than
the size of the box, as the vertical height in
addition to the diameter; so that я box of three inches diameter and one inch deep would require
pieces of four and five inches respectively for the cover and bottom.
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The round plate of shell is first placed centrally over the edge of the ring, as in Fig. 39 it is slightly
squeezed with the small round-edged block g, and the entire press is then lowered into the boiling water;
in one quarter, or half an hour, it is transferred to the bench, and g is pressed entirely down, which bends
the shell into the shape of a saucer, as at Fig. 40, without cutting or injuring the tortoiseshell, after
which the press is cooled in the water-trough. The same processes are repeated with the die d, which
has a rebate turned away to the thickness of the shell, and perfects the angle of the box to the section
Fig. 41, ready for completion in the lathe; it is however safer to perform each of these processes at twice,
with two boilings.
When the shell is insufficiently thick, two pieces are joined together, and should they from the nature
of the shell be of irregular thickness, the thick and thin parts respectively are placed in contact; for
such cases the dies c e, of a larger mould, are used. The piece d is adapted to boxes of various depths,
or to the tops or bottoms respectively, by slipping loose rings upon it to contract the length of its smaller
part.
When the box is required to have a device, an engraved die f is substituted in place of a The s.me
tools are also used for horn boxes, and for the embossed wooden boxes, but the latter process is mostly
performed in the dry way, the warmth being supplied by heated plates, put above and below the two
parts of the mould which are then compressed, and the whole is allowed to cool in the air.
The Manuel describes the construction of inferior boxes, " Tabatières de morceaux," in which small
pieces of tortoiseshell with bevelled edges are carefully fitted together with the file and arranged along
the bottom and up the sides of the mould; or else they are first pressed into a flat plate, and made into
a box as a separate process; but the joints, from the manner in which they are made, can scarcely ever
escape observation.
The Boites de très-petits morceaux" are made of still smaller fragments, which are often cemented
on a thin leaf of shell to ensure their better union; and lastly, the Boites de drogues" are made of the
fine dust and filings, which are passed through a sieve, and treated in other respects much in the same
manner as the foregoing, but these boxes are quite opaque and brittle; a thin hoop of good tortoiseshell
is sometimes inserted in the mould, to form the rebate of the box, which alone is then transparent; at
other times, the shavings are mixed with mineral coloring matters, to imitate granite, lapis-lasuli, and
other stones.
After the lapse of ten days or a fortnight, it sometimes happens the box shows a tendency to recover
its primary form, that of a flat plate, and from being cylindrical on the edge, it becomes in a slight de-
gree conical and larger without. After being again returned to the mould, boiled, and pressed, its figure
is in general permanent.
This disposition is turned to useful account in restoring the fitting of a box that may have become
loose, as by dipping the lower part, or the rebate, into warm water, it will expand and fill out the lid,
but it requires care that it be not overdone.
The tortoiseshell boxes usually made, are those which are veneered upon a body or fabric of wood,
for which purpose the plates are scraped and filed to a uniform thickness, and glued on much the same
as veneers of wood; generally fine glue is the only cement used, but various compositions are resorted to
by different manufacturers. To improve the appearance of the shell, and to conceal the glue and wood
beneath, the back of the veneer is rubbed with a mixture of lampblack, vermilion, green, chrome, or
white, in fish glue; the colors are applied over the entire surface, or partially to modify the effect, and
thus prepared the veneers are glued upon the boxes.
In tortoiseshell works inlaid with mother-of-pearl and gold or silver plates or wire, the substances to
be inlaid are first prepared; and for pearl shell a paper is pasted on a thin piece of pearl, the pattern is
drawn thereupon, and the small pieces are cut out with a fine buhl-saw gold and silver plates are some-
times also thus sawn out.
A plain mould similar to Fig. 39, but rectangular, and with plain dies, as c and e, is used; a few
shavings of tortoiseshell are first placed on the piece c, to make a bed or cushion, then a piece of paper
to prevent them from adhering to the thin leaf of tortoiseshell, which is next inserted in the mould. The
small pieces of pearl shell, &c. to constitute the pattern, are then carefully arranged in their intended
positions, and the top plate e is very carefully lowered into the mould above the pieces, 80 that it may
not misplace any of them. The mould is then slid into the press, slightly squeezed, and plunged into the
copper fa an hour, carried to the bench and screwed moderately tight; the work is now examined to
see that nothing is misplaced, it is returned to the caldron for a time, and the final squeeze is given by
the entire force of three men, after which, whilst still under pressure, the whole is plunged into the cold
water. The tablet is then fit to be smoothed and glued on the wooden box.
It will be readily conceived, that the force required depends upon the dimensions of the work; pieces
of three or four inches square require all the appliances described; whereas the little ornaments upon
razors and knives, may be pressed in with much slighter apparatus, such in fact as were previously de-
scribed as being used in moulding them. In cutlery, a different method is generally resorted to, which
applies equally well to ivory and pearl shell, substances which cannot be submitted to the softening and
moulding processes employed for horn and tortoiseshell.
The cutlery works which are dotted all over with little studs of gold or silver, are drilled from thin
pattern plates of brass or steel in which the series of holes have been carefully made the drill or
passer" has an enlargement or stop, which, by encountering the surface of the pattern plate, prevents
the point of the drill from penetrating beyond the assigned depth into the handle; the holes in the
ivory or pearl shell are then filled with silver or gold wire, which is either filed and polished off level
with the general surface, or allowed to project as little studs.
For small ornaments they use pattern plates or templets of hardened steel, pierced with the exact
form. The cutting tool somewhat resembles an ordinary breast-drill eight or ten inches long, and like
it, is used with the breast-plate and drill-bow; but the extremity of the tool is cleft, or made in two
branches, which, left to themselves, spring open to the extent of an inch or more; each half of the tool
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has a shoulder or stop, which bears upon the surface of the steel guard-plate, as in the drill, and a
rectangular cutting part that protrudes through the shield-plate as far as the required depth of the
recess, and is sharpened both at the end and side, or at the ends only.
When the elastic tool or spring-passer" has been compressed 80 as to enter the guard-plate, it is
put in motion, and flounders about in all directions, 80 far as it can expand, and routs or cuts out the
shallow recess; the small ornaments are punched out, fixed by two rivets, and smoothed off; these
processes are very expeditious, and produce accurate copies of the respective pattern-plates employed.
The tortoiseshell, when unnecessarily thick for a single scale for a penknife, is sawn to serve for two;
and the colors are brightened up by placing a piece of Dutch leaf beneath the same; they are finally
polished on the various wheels used by the cutler. Tortoiseshell has been manufactured into hollow
walking-sticks, and even bonnets.
Whalebone may be considered as a kind of horn; which latter substance it resembles perfectly, both
in its chemical and principal physical properties; and is particularly interesting as forming the transi-
tion from horn to hair.
It is the substitute for teeth in the Greenland whale, and in the black southern wale; but is not
found in any of the cetaceous animals that have tecth.
From the roof of the mouth hang down on each side the tongue about three hundred plates of
whalebone, all the blades on one side being parallel to each other and at right angles to the jaw-bone.
The average length of the middle blades is about nine feet, but they have occasionally occurred of the
length of fourteen or fifteen feet.
The general color of whalebone is a dusky grayish black, intermixed with thin stripes or layers of a
pale color, which are often almost white-very rarely the entire flake is milk-white.
The preparation of the whalebone for use is very simple. It is boiled in water for several hours,
by which it becomes soft enough to be cut up while hot, in lengths of different dimensions, according
to the use to which it is to be applied. Whalebone that has been boiled, and has become cold again, is
harder and of a deeper color than at first; but the jet-black whalebone has been dyed, and by the
usual processes it takes very bright and durable colors.
Whalebone is now principally used for the stretchers for umbrellas, and as a substitute for bristles in
common brushes; it is also plaited into whips, and solid pieces of mixed shades are twisted for
walking-sticks; but it does not admit of being soldered or joined together like tortoiseshell. Whale-
bone also furnishes a very neat and durable covering for pocket-telescopes. Narrow pieces of the
material are grooved or made into ribs, by drawing them like wire through a corresponding aperture
in a steel plate, after which they are wound round the tube, and tucked under" the rings at the ex-
tremities. Broad flat strips of the party-colored whalebone, (the light portions of which absorb the
green dye,) are also used these are secured by narrow black barids which overlap the two edges, and
other bands are wound around the ends also.
Ivory, the tusk or weapon of defence of the male elephant, and of which each animal has two, is
placed by the chemists intermediately between bone and horn, and its mechanical characters corrobo-
rate the position. It is generally considered that the male elephant alone possesses tusks, commercially
known as elephants' teeth, but this appears questionable, as by many the female is reported to have
tusks likewise, but of smaller size, and some consider the latter produce the small solid tusks called
ball ivory," used for making billiard balls.
Ivory has less gelatine than bone; but as it leaves the animal in a state fit for use, without the neces-
sity of removing any of its component parts for its purification, its elasticity and strength are not im-
paired by such abstraction. Ivory is not therefore so brittle as bone, neither does it splinter so much
when broken, but its greater ultimate share of animal matter leaves it more sensible to change of form
and size.
The shape of the tusk is highly favorable to its use, as it is in general solid for above half its length,
and of circular or elliptical section; it is entirely free from the vessels or pores often met with in bone,
and although distinctly fibrous, it cannot be torn up in filaments like horn, nor divided into thin flexible
leaves, as for miniatures, otherwise than by the saw.
Its substance appears very dense, and without visible pores, as if beautifully cemented by oil or wax;
and notwith anding that it possesses so large a share of lime, it admits of being worked with exquisite
smoothness, and is altogether devoid of the harsh, meager character of bone. It is in all respert; the
most suitable material for ornamental turning, as it is capable of receiving the most delicate lines and
cutting, and the most slender proportions.
The general supply of ivory is obtained from the two present varieties of the animal, the Asiatic and
the African: they are considered by physiologists to be distinct species, and to be unlike the extinct
animal from which the Russians are said to obtain their supply of this substance; which, although
described as fossil ivory, does not appear to have undergone the conversion commonly implied by the
first part of the name, but to be as suitable to ordinary use as the ivory recently procured from the
living species. An extract from the interesting account of 44 The Elephant of the Lena" is subjoined as
a note.
" The Mammoth, or Elephant's bones and tusks, are found throughout Russia, and more particularly in Eastern Siberia
and the Arctic marshes. The tusks are found in great quantities, and are collected for the sake of profit, being sold to the
turners in the place of the living ivory of Africa, and the warmer parts of Asia, to which it is not at all inferior."
" Almost the whole of the ivory-turner's work, made in Russia, is from the Siberian fossil ivory; and sometimes the
tusks, having hitherto always been found in abundance, are exported from thence, being less in price than the recent.
Although, for a lung series of years, very many thousands have been annually obtained, yet they are still collected every
year in great numbers on the banks of the larger rivers of the Russian empire, and more particularly those of farther
Siberia."- Naturalist's Library, 1836. Mammalia, vol. V., p. 133.
The Mammoth terth are but rurely exposed for sale in this country. I only learn of two; the one weighed 186 pounds,
was 10 feet long, of fine quality, and except the point, which was cracked, was cut into keys for pianofortes; the other also
was large, but very much cracked and uscless. Of the latter I have a specimen: the substance of the Ivory between the
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The hippopotamus, or river-horse, supplies the ivory used by the dentist, which is imported from the
East Indies and Africa; the animal, in addition to twenty grinders, has twelve front teeth, the whole of
which agree in substance with ivory, but not in their size or arrangement. The six in the upper jaw
are small, and placed perpendicularly; in the lower jaw of the hippopotamus the two in the centre are
long, horizontal, and straight, the two next are similar, but shorter; but the two external semicircular
teeth are those 80 highly prized by the dentists on account of their superior size, and are those usually
referred to when the "sea-horse" or hippopotamus tooth is spoken of, although the animal is in reality a
quadruped inhabiting rivers and marshy places.
The circular hippopotamus teeth are covered exteriorly with a thick coat of enamel, which entirely
resists steel tools, and will even strike fire with that metal; it is usually removed upon the grindstone*
in order to arrive at the beautiful ivory within, which, owing to the peculiarity of its section, is better
adapted to the construction of artificial teeth than the purposes of turning; the other teeth are tolera.
bly round, and fit for the lathe.
The ivory of the hippopotamus is much harder than that of the elephant, and upwards of double the
value; in color it is of a purer white, with a slight blue cast, and is almost free from grain. The parts
rejected by the dentists are used for small carved and turned works.
In texture it seems almost intermediate between the proper ivory and the pearl shell; as when it is
turned very thin, it has a slightly curdled, mottled, or damasked appearance, which is very beautiful;
the general substance is quite transparent, but apparently interspersed with groups of opaque fibres,
like some of the minerals of the chatoyant kind.
The teeth of the walrus, sometimes called the sea-cow, which hang perpendicularly from the upper
jaw, are also used by the dentists; the outer part, or the true ivory, nearly resembles the above, but
the oval centre has more the character of coarse bone; it is brown, and appears quite distinct. The
long straight tusks of the sea-unicorn or narwal, which are spirally twisted, also yield ivory; but they
are generally preserved as curiosities. These two kinds are principally obtained from the Hudson's
Bay Company.
The masticating teeth of some of the large animals are occasionally used as ivory; those of the
spermaceti whale are of a flattened oval section, and resemble ivory in substance; but they are dark-
colored towards the centre, and surrounded by an oval band of white ivory: like that of the aquatic
varieties generally, they are not much used.
The grinders of the elephant are occasionally worked; but their triple structure of plates of the hard
enamel, of softer ivory, and of still softer cement, which do not unite in a perfect manner, render them
uneven in texture. Owing to the hardness of the plates of enamel, the grinders are generally worked
by the tools of the lapidary; they are but little used, and when divided into thin plates are disposed to
separate, from change of atmosphere, the union of their respective parts being somewhat imperfect.
They are made into small ornaments, knife-handles, boxes, &c.
The tusk of the elephant is, however, of far more importance than all these other kinds of ivory, and
appears to have been extensively used by the Greeks and Romans. Amongst the former, Phidias was
famous for his statues, thrones, and other works of embellishment, made in ivory combined with gold,
an art described as the Toreutic. In reference to the construction of ivory statues, Monsieur Quatremère
de Quincy, in his great work on ancient sculpture, advances some curious speculations of their having
been formed upon centres or cores of wood, covered with plates of ivory; and also that the ancients
were enabled to procure larger elephants' teeth, or possessed the means of softening and flattening out
those of ordinary size, from which to obtain the pieces presumed to have been thus employed.
These questionable suppositions, particularly the last, scarcely seemed called for, as solid blocks of
ivory of the sizes commonly met with, would appear to be sufficient for the construction of colossal
figures, in the mode ingeniously demonstrated by M. de Quincy in his plates 26 to 31. It is much to be
regretted that none of these statues have descended to our times.
One of the constituent parts of ivory being animal matter, we should naturally expect it to be less
durable t' an the inorganic materials, in which numerous fine specimens of ancient art still exist in great
comparative perfection. Ivory appears not to suffer very rapid decay, in the lengthened deposition in the
frozen earth of Siberia, nor when immersed in water; but various specimens in the British Museum, appa-
rently less favorably situated, and in contact with the air, exhibit the effect of time, the ivory being decom-
posed and divided into flakes and pieces which exhibit its lamellar structure in a very satisfactory manner.
Elephants' teeth differ considerably in their size, weight, and appearance. The outsides of the African
teeth run through all the transparent tints of light and deep orange, hazel, and brown, and some are
almost black. Those from Asia are similar, although generally lighter, and frequently of a kind of
opaque fawn, or stone-color; they have seldom the transparent character of the African teeth; and
they commonly abound in cracks of inconsiderable depth, from which the others are comparatively free.
Some teeth are as long as from eight to ten feet, and as heavy as 150, rarely 180 lbs. each tooth; some-
times they are only as many inches long, and about one inch in diameter, and of the weight of five or
six ounces, and even lighter; the teeth less than from 10 to 14 lbs. are called "scrivelloes." In section,
the tusks are rarely quite circular, sometimes nearly elliptical, seldom exceeding the proportions of four
to five, but commonly less exact than either of these forms; Figs. 43, 44, and 45, are accurately reduced
from sections of teeth; the largest tusk the author has met with measured eight and a quarter inches
the longest, and seven inches the shortest diameter of the irregular oval.
cracks appears quite of the ordinary character, although the Interatices are filled with a dry powder resembling chalk. Both
teeth were solid unto within six inches of the root.
The enamel of the hippopotamus is much thicker, but similar to that of the generality of masticating teeth, which is
found upon analysis to agree very nearly with the hard porcelanous shells. The enamel is sometimes scaled off by driving
a thin chisel between it and the Ivory; and I learn, the flame of the blowpipe is likewise frequently used for the purpose
of separating it. Several of the other teeth have enamel, but the semicircular tooth by far the most abundantly.
+ Le Jupiter Olympien, ou l'Art de la Sculpture Antique. Paris, 1815.
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The curvature of the teeth is sometimes as much as the half-circle, as in Fig. 46, and occasionally even
80 little or less than the sixth, as in Fig. 42; they are sometimes finely tapered off, especially in the
African teeth, at other times their ends are very much worn away,-in rare instances, to the extent of a
third of their apparent length, and generally more
80 on the one side of the centre than the other.
42.
Other teeth end very abruptly, as if they had
been broken and repointed before they left the head
of the animal, in which they are generally inserted
for about one-fourth their length.
The teeth are hollow about half-way up, and a
speck, sometimes called the nerve, but in reality
the apex of the successive hollows, is always visi-
44.
ble throughout the length of the tusk to its extreme
43.
end, the tooth being formed by layers deposited
on a vascular pulp after the manner of teeth gen-
erally.
The inner and outer surfaces of the teeth are in
general tolerably parallel, and exteriorly they are
curved in the one direction only, 80 as to lie nearly
45.
flat on the ground; but occasionally they are much
curved in both directions, as represented in Figs.
47 and 48 the smaller is beautifully formed, and
resembles in shape a handsome bullock's horn, the
other is furrowed throughout its length, and ap-
pears the result of disease or injury.
46.
The choice of ivory in the tooth is admitted by
the most experienced to be a very uncertain matter; of course, for the purposes of turning, a solid cone
would be the most economical figure, but as that form is not to be met with, we must be satisfied with
47,
48.
the nearest approach that we can find to it, and select the tooth as nearly straight, solid, and round as
possible, provided the other prognostics are equally favorable.
The rind should appear smooth and free from cracks, and if the heart should be visible at the tip,
the more central it is the better; by the close inspection of the tip, from which the bark is always more
or less worn away, it may be in general learned whether the tooth is coarse or fine in the grain, trans-
parent or opaque, but the color of the exterior coat prevents a satisfactory judgment as to the tint or
complexion of the ivory within.
After the most careful scrutiny on the outside of the tooth, however, the first cut is always one of a
little anxious expectation. as the prognostics are far from certain, and before proceeding to describe the
preparation of ivory, I will say a few words of its internal appearance when exposed by the saw.
The African ivory, when in the most perfect condition, should appear, when recently cut, of a mellow.
warm, transparent tint, almost as if soaked in oil, and with very little appearance of grain or fibre; it is
then called transparent or green ivory, from association with green timber; the oil dries up considerably
by exposure, and leaves the material of a delicate, and generally permanent tint, a few shades darker
than writing-paper.
The Asiatic ivory is of a more opaque dead-white character, apparently from containing less oil, and
on being opened it more resembles the ultimate character of the African, but it is the more disposed of
the two to become discolored or yellow. The African ivory is generally closer in texture, harder under
the tools, and polishes better than the Asiatic, and its compactness also prevents it from 80 readily
absorbing oil, or the coloring matter of stains when intentionally applied.
The rind is sometimes no more than about one-tenth of an inch in thickness, and nearly of the color
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of the inner ivory, but occasionally it is of double that thickness, dark-colored, and partially stains the
outer layers. As we do not find all specimens of the most perfect kind, we must be prepared to expect
others, especially amongst the larger teeth, in which the grain is more apparent, but it generally dies
away towards the centre of the tooth, the outside being the coarser; the regularity of the grain some-
times gives it the appearance of the engine-turning on a watch-case.
In some teeth, the central part will appear of the transparent character, the outer more nearly white;
and the transparent teeth often exhibit, at the solid parts, white opaque patches, which are frequently
of a long oval form. Amongst the white ivory, the teeth are often found to be marked in rings alter-
nately light and dark colored; these are called 'ringy or cloudy."
In those teeth in which there appears to be a deficiency of the animal oil, the intervals between the
fibres occasionally assume the chalky character of bone, and are disposed to crumble under the tools
unless they are very sharp; in this they resemble the softer parts of woods when worked with blunt
tools; sometimes the ivory is not only coarse but dark or brown, and the two defects not unfrequently
go together.
The cracks occasionally penetrate further than they appear to do when viewed from the outside, and
more rarely a very considerable portion of the tooth is injured by a musket-ball, although the gold and
silver bullets, said to be used by the Eastern potentates, are exceedingly scarce, or else transmuted into
iron, of which metal they are commonly found, and less frequently of lead. The ball generally lacerates
the part very much, and a new deposite of bony matter is made that fills up all the interstices, incrusts
the hollow, and leaves a dotted mottled mass extending many inches each way from the ball, and which
completely spoils that part for any ornamental purpose.
Preparation of Ivory.-On account of the great value of ivory it requires considerable judgment to
be employed in its preparation, from three conditions observable in the form of the tusk; first, its being
curved in the direction of its length; secondly, hollow for about half that extent, and gradually taper
from the solid state to a thin feather edge at the root; and thirdly, elliptical or irregular in section.
These three peculiarities give rise to as many separate considerations in cutting up the tooth with the
requisite economy, as the only waste should be that arising from the passage of the thin blade of the
saw: even the outside strips of the rind, called spills, are employed for the handles of penshives, and
many other little objects; the scraps are burned in retorts for the manufacture of ivory black, employed
for making ink for copperplate printers, and other uses; and the clean sawdust and shavings are some-
times used for making jelly.
The methods of dividing the tooth either into rectangular pieces, or those of circular figure required
for turning, are alike in their early stages until the lathe is resorted to: I propose, therefore, to begin
with the former. The ivory saw, Fig. 49, is stretched in a steel frame to keep it very tense; the blade
generally measures from fifteen to thirty inches long, from one and a half to three inches wide, and
about the fortieth of an inch thick; the teeth are rather coarse, namely, about five or six to the inch,
and they are sloped a little forward, that is, between the angle of the common hand-saw tooth and the
cross-cut saw. The instrument should be very sharp and but slightly set; it requires to be guided very
correctly in entering, and with no more pressure than the weight of its own frame, and it is commonly
lubricated with a little lard, tallow, or other solid fat.
49.
The cutler generally begins at the hollow, and having fixed that extremity parallel with the vice, with
the curvature upwards, he saws off that piece which is too thin for his purpose, and then two or three
parallel pieces to the lengths of some particular works, for which the thickness of the tooth at that part
is the most suitable; he will then saw off one very wedge-form piece, and afterwards two or three more
parallel blocks.
In setting out the length of every section, he is guided by the gradually increasing thickness of the
tooth; having before him the patterns or gages of his various works, he will in all cases employ the
hollow for the thickest work it will make. As the tooth approaches the solid form, the consideration
upon this score gradually ceases, and then the blocks are cut off to any required measure, with only a
general reference to the distribution of the heel, or the excess arising from the curved nature of the tooth,
the cuts being in general directed, as nearly as may be, to the imaginary centre of curvature. The
greatest waste occurs in cutting up very long pieces, owing to the difference between the straight line
and the curve of the tooth, on which account the blocks are rarely cut more than five or six inches long,
unless for some specific object.
In subdividing those blocks which are entirely solid, no great difficulty is experienced in those which
are nearly solid, as in Fig. 50, the first step is to cut a central slice just thick enough to avoid the hollow,
unless the pieces a b are required to have some particular size; c d would serve for leaves for minia-
tures or veneering, and the remainder would be cut up of any required sizes, as sketched beyond c d.
For square pieces of similar size, the block is cut into parallel slabs; for bevelled pieces, as the taper
handles of knives and razors, the slabs are cut out wedge-form, the thick end of one against the thin
end of the next, as at e f these slabs are afterwards divided with parallel or inclined cuts, either with
the frame or the circular saw.
In flat works, such as razor and knife handles, the broad surfaces, if cut radially, would show the
edges of the rings or layers of the ivory; but cut parallel with the curve (If as the tangent, the grain is
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much less observable, and the ivory appears finer In the keys for pianofortes this is particularly at
tended to; the finest broad keys are always cut upon the flat side of the oval, as atf, those upon the
long diameter are cut into the narrow pieces called tails, (used between the black keys,) and the inter
mediate parts are cut obliquely as at g; this causes much waste.
For such pieces as have large hollows, more management is neces-
50.
sary, as the thickness and curvatures of the material have to be jointly
considered. When the hollows are thin, they are cut into squares or
handles as large as the substance will allow; but on account of the
circular section of the tooth, some of the pieces, if not all, must neces-
sarily be angular or wedge-form; as regards pieces for the lathe, this
is of little consequence.
In all cases the ent. re division of the block or ring should be deter-
mined upon, and carefully marked in pencil upon the end of the piece,
before the saw is used.
When the tusk is cut up exclusively for turnery-work, the first cut
is more generally made where the hollow terminates, which spot is
ascertained hy thrusting a small cane or a wire up the tooth; and every
cut is directed as nearly as possible at right angles to the curve of the
tusk, or to the centre of the circle, as before described. Unless the
tooth is very far from circular, it is usual to prepare the principal
quantity into cylinders or rings, as large as they will respectively
d
hold, and the diagrams, Figs. 51, 52, and 53, are intended to explain the
b
best mode of centreing the pieces, or placing them in the lathe.
If, as in preparing an ordinary block of wood, a circle were made at each end, and the work were
chucked from the centres of the circles, as at o, Fig. 51, the largest cylinder that could be obtained would
53.
52.
51.
c
b
d
be that represented by the four sides of the dotted rectangle within that figure. Very much less waste
would result from placing the centres 80 much nearer to the convex side, as to obtain the cylinder rep-
resented in Fig. 52, by allowing the waste to be equally divided between the points a, c, and e.
It is however more economical, to cut those teeth which are much curved into the shortest blocks, and
the Fig. 53, which represents the proportions more commonly adopted, shows the small comparative de-
gree of waste that would occur in a piece of half the length of the others, when centred in the most
judicious manner.
The first process in preparing to rough-turn the block, is to fix it slenderly in the lathe between the
prong chuck and the point of the popit-head, and its position is progressively altered by trifling blows
upon either end, until when it revolves slowly, and the common rest or support for the tool is applied
against the most prominent points a, e, and c, respectively, the vacancies or spaces opposite to each, at
d,b, and f, shall be tolerably equal; 80 that, in fact, about a similar quantity may have to be turned away
from the parts a, e, and c, for the production of the cylinder, represented by the dotted lines within the
figure.
The centres having been thus found, they should be made a little deeper with a small drill; and then
the one end of the block being fixed upon the prong chuck, the opposite extremity, supported by the
centre, is turned for a short distance slightly conical, ready for fixing in a plain boxwood chuck, or a
brass chuck lined with wood, to complete the rough preparation, unless indeed it is entirely performed
upon the prong chuck.
With the decrease in length, less attention is requisite in the centreing, on account of the interference
of the curvature of the tooth, and the pieces may be at once rasped to the circular form, and then chucked
either in a hollow chuck, or else by cement or glue, against a plain flat surface.
When the blocks of ivory are long and much curved, a thin wedge-form plate may be sometimes sawn
from the end, in preference to turning the whole into shavings; the end is turned cylindrically for a short
distance, just avoiding to encroach on the lower angle of the block, and as soon as practicable, a parting
tool is used for cutting a radial notch for the admission of the saw, which may be then employed in re-
moving a thin taper slice. The process is at any rate scarcely attended with more trouble than turning
the material into shavings, and thin pieces are retained for a future purpose, such in fact as those repre
sented beyond the dotted lines at the ends of the figures.
The hollow pieces of ivory are treated much in the same manner as those which are solid, and into
which latter condition they are sometimes temporarily changed, by rasping a piece of common wood, such
as beech, to fit into the hollow, driving it in pretty securely, but so as not to endanger splitting the ivory
the work is then centred as recently explained, the chuck and centre being in this case received in the
wood.
With the hollow pieces, the process of turning must be repeated on their inner surfaces, for which
purpose a side cutting tool, with a long handle for a secure grasp, should be used: the toc! should be
held very firmly, so as to withstand the jerking intermittent nature of the cut, until the irreg larities are
reduced.
For this purpose the aliding-rest is very desirable, as the tool is then held perfectly fast without effort
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on the part of the individual, and if the chucking be correctly done, the greatest possible economy of the
material is attained; the hand tools succeed very well on the outer surface, as the rest or support upon
which they are then placed is 80 close to every point of the exterior surface, that they may be held se-
curely with less effort, although the sliding-rest is nevertheless desirable there also.
When the ivory hollow is thin, and far from circular, the material would be turned entirely into
shavings, in attempting to produce a circular ring; the circular dotted lines in Figs. 43 and 44, are in-
tended to explain this. Fig. 43 might be turned into an oval ring; but it is more usual to cut such
irregular hollows into small square and round pieces, as explained.
When thin rings or short tubes are required, they are frequently cut one out of the other in the lathe,
in preference to wasting the material in shavings; this is done with the parting tool, as in Fig. 54; an
incision being made of uniform diameter from each end, and continued parallel with the axis, until the
55.
54.
two cuts meet in the centre; very short pieces may be thus divided from the one end only. When the
rings are large and thin, it is desirable to plug them at one or both ends, with a thin piece of dry wood,
turned as a plug to fill the diameter, and prevent the ivory from becoming oval in the course of
drying.
Fig. 55 explains the mode of preparing such an object as a snuff-box out of a solid block; that is,
with the ordinary parting tool entered from the front, and the inside parting tool entered from within
the incisions of which meet and remove a series of rings. The dotted lines represent the paths of the
respective tools, the shaded parts the ring obtained, and the black lines the tools themselves. An
apérture must necessarily be made in the centre, of a diameter equal to the extreme width of the tool
but after the removal of the first, or central ring, a tool of considerably larger size may be used to ex-
tract a much wider ring; and a little tallow or oil applied to the parting tools, will, in a great measure,
prevent the shavings of the ivory from sticking to them and impeding their progress.
Ivory requires a similar drying, or seasoning, to that recommended for wood; as when the pieces cut
out of the tooth are too suddenly exposed to hot dry air, they crack and warp nearly after the same
manner as wood, and the risk is the greater the larger the pieces; and on this account ornaments turned
out of ivory or wood, especially those composed of many parts, should not be placed upon those
chimney-pieces which, from their size, are so close to the fire as to become heated thereby in any sensi-
ble manner.
Notwithstanding the difference between the component parts of wood and ivory, and that the latter
does not absorb water in any material degree, it is subject to all the changes of size and figure experi-
enced by the woods, and in one respect it exceeds them, as ivory alters in length as well as width,
whereas from the former change wood is comparatively free.
The change, however, is very much less in the direction of the length than the width; this is particu-
larly experienced in billiard-balls, which soon exhibit a difference in the two diameters, if the air of the
apartment in which they are used differ materially from that in which the ivory had been previously
kept. The balls are usually roughly turned to the sphere for some months before they are used, to
allow the material to become thoroughly dry before being turned truly spherical; and in some of the
clubs they even take the precaution of keeping the rough balls in their own billiard-room for a period,
to expose them to the identical atmosphere in which they will be used.
It may be asked, what means there are of bleaching ivory which has become discolored the author
regrets to add that he is unacquainted with any of value. It is recommended in various popular works
to scrub the ivory with Trent sand and water, and similar gritty materials; but these would only pro-
duce a sensible effect, by the removal of the external surface of the material, which would be fatal to
objects delicately carved by hand, or with revolving cutting instruments applied to the lathe.
Perhaps it may be truly advanced, that ivory suffers the least change of color when it is exposed to
the light, and closely covered with a glass shade. It assumes its most nearly white condition when the
oil, with which it is naturally combined, is recently evaporated; and it is the custom in some thin works,
such as the keys of pianofortes, to hasten this period, by placing them for a few hours in an oven heated
in a very moderate degree, although the more immediate object is to cause the pieces to shrink before
they are glued upon the wooden bodies of the keys. Some persons boil the transparent ivory in pearl-
ash and water to whiten it; this appears to act by the superficial extraction of the oily matter as in
bone, although it is very much better not to resort to the practice, which is principally employed to
render that ivory which is partly opaque and partly transparent, of more nearly uniform appearance.
It is imagined by some that ivory may be softened 80 as to admit of being moulded like horn or
tortoiseshell: its different analysis contradicts this expectation; thick pieces suffer no change in boiling
water, thin pieces become a little more flexible, and thin shavings give off their jelly, which substance
is occasionally prepared from them. Truly, the caustic alkali will act upon ivory as well as upon most
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ANIMAL MATTER USED IN THE ARTS.
animal substances, yet it only does 80 by decomposing it; ivory, when exposed to the alkalies, first be-
comes unctuous or saponaceous on its outer surface, then soft, if in thin plates, and it may be ultimately
dissolved, provided the alkali be concentrated; but it does not in any such case resume its first con
dition.
Ivory is not in all cases used in solid pieces, to which the foregoing remarks principally apply; but
is frequently cut into thin leaves and glued upon fabrics of wood, for the manufacture of small orna-
mental boxes, and works of various kinds, after the manner of the veneers of wood, or the plates of
tortoiseshell; it is also used in buhl works, combined with ebony. Such thin plates are usually cut out
of the solid block, parallel with the axis of the tooth, as at cd, in Fig. 50, with a fine feather-edge
veneer saw; but the mode introduced in Russia for cutting veneers spirally from a cylindn al block of
wood, with a knife of equal length, (as if the veneer were uncoiled like a piece of silk or cloth from a
roller,) has been latterly applied to the preparation of ivory into similar veneers, converting the cylinder
of ivory into one ribbon, probably by the action of a reciprocating-saw.*
The modes pursued in these veneered works are analogour to those to be described in the
article in reference to woods; it is, therefore, only necessary to a. d a few words on the white-fish
glue, or " Diamond cement," as it is sometimes called, which is very often used for ivory-work, both in
attaching ivory to ivory, and ivory to wood.
This cement is made of isinglass, (which is prepared from the sound, or swimming-bladder of the
sturgeon,) dissolved in diluted spirits of wine, or more usually in common gin. The two are mixed in a
bottle loosely corked, and gently simmered in a vessel containing boiling water: in about an hour the
isinglass will be dissolved and ready for use; when cold, it should appear as an opaque, milk-white,
hard jelly; it is remelted by immersion in warm water, but the cork should be at the time loosened,
and it may be necessary, after a time, to add a little spirit to replace that lost by evaporation. Isin-
glass, dissolved in water alone, soon decomposes.
Factitious ivory and tortoiseshell have been prepared in France in thin plates or veneers.
Having adverted to many animal substances suitable to the mechanical arts, obtained from various
inhabitants of the land and water, let me, in conclusion, mention some that are obtained from the
feathered tribes-namely, the eggs of birds; which, although of limited application in the arts of em-
bellishment, have at all ages served as models or standards of beautiful form.
They may be made to answer in a very perfect manner for the bodies of vases, the feet and upper
parts of which are turned out of wood or ivory for this purpose the egg-shells have been commonly
used in their entire state, a hole having been made at the top and bottom for the extraction of their
contents, and the attachment of the remaining parts. I have now the pleasure to bring before the
reader a method of cutting the shells of the eggs of our various domestic fowls, and other birds, for the
formation of vases with detached covers.
In the accompanying drawing is represented the nose of a lathe, with an egg chucked ready for cut-
ting. Fig. 56 is the section of a chuck for holding the eggs to prepare them for the chuck represented
in Fig. 57.
Fig. 56 is what is generally termed a spring chuck,
56.
and is made by rolling stout paper, thoroughly moist-
ened with glue, upon a metal or hard-wood cylinder,
the surface of which has been greased to prevent
the paper adhering to it, and upon which it must re-
main until perfectly dry, when it may be removed,
and cut or turned in the lathe as occasion may re-
quire.
This sort of chuck is very light, easily made, and
well adapted for the brittle material it is intended to
hold. Before fixing the egg in it, the inner surface
should be rubbed with some adhesive substance,
(common diachylon answers exceedingly well ;) when
57.
a
this is done, the egg should be carefully placed in
the chuck, the lathe being slowly kept in motion
by one hand, whilst with the other the operator
must adjust its position, until he observes that it runs
perfectly true; then, with a sharp-pointed tool he
must mark the centre, and drill a hole sufficiently
large for the wire in the chuck, Fig. 57, to pass freely
through.
B
When this is done, the egg must be reversed, and
the same operation repeated on the opposite end;
6
its contents must then be removed by blowing care-
fully through it it is now ready for cutting, for which purpose it must be fixed in the chuck shown in
Fig. 57, which is made as follows:
A is a chuck of box, or other hard wood, having a recess turned in it at a b, into which is fitted a
piece of cork, as a soft substance for the egg to rest against. B is a small cup of wood, with a piece of
cork fitted into it, serving the same purpose as that in A. A piece of brass, d, is to be firmly screwed
into the chuck A, and into that a steel wire, screwed on the outer end.
Monsieur H. Pape, of Paris, planoforte manufacturer, has taken out patents for this method of cutting ivory spirally
into sheets. A specimen, 17 inches by 38 inches, and about one-thirtieth of an inch thick, glued upon a board, may be
seen at the Polytechnic Exhibition in Regent-street, and M. Pape advertises to supply sheets as large as 30 by 150 inches.
He has veneered a pianoforte entirely with ivory.
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ANTHRACITE COAL.
37
ANTHRAOITE COAL The annexed table, taken
Horse
Pounds
Horse
Pounds
Horse
Pounds
from O. E Leonard's valuable work, The Mechanical
Power.
Coal.
Power.
Coal.
Power.
Coal.
Principia," shows the usual consumption of coarse an-
thracite coal a day, by different-sized engines. The
4
168
38
1596
70
2940
column marked " Horse Power" shows the horse power
6
252
40
1680
72
3024
of the engines, the column marked "Pounds Coal"
8
836
42
1764
74
3108
shows the number of pounds consumed a day of 12
10
420
44
1848
76
3192
hours. Example: the number of pounds of anthracite
12
504
46
1932
78
3276
coal used in a day, to supply an engine working 40
14
588
48
2016
80
3360
horse power, is 1680. Again: let it be required to find
16
672
50
2100
82
3444
the number of pounds of anthracite coal per day, to
18
756
52
2184
84
3528
supply an engine working 100 horse power. Find 100
20
840
54
2268
86
3612
in the column marked Horse Power," opposite to this
22
924
56
2352
88
3696
number in the column marked Pounds Coal," will be
24
1008
58
2436
90
3780
found 4200 pounds.
26
1092
60
2520
92
3864
The following table is calculated principally for the
28
1176
62
2604
94
3948
Southern States, where the Southern Pine is used for
30
1260
64
2688
96
4032
fuel instead of coal; the column marked Horse
32
1344
66
2772
98
4126
Power," shows the number of horse power the engine
84
1428
68
2856
100
4200
is working; the column marked Cords," shows the
36
1512
number of cords that the engine consumes per day
(12 hours;) the column marked "Hours," shows the number of hours per day, which the engine is
supposed to run.
EXAMPLE-Required the number of cords of South-
ern Pine to drive three run of 41 feet stones grinding
Horse
Horse
Power.
Cords.
Hours.
Power.
Cords.
Hours.
corn, the number of horse power required being about
45. Find 45 in the column marked Horse Power,"
4
t
12
45
opposite to this number in the column marked Cords,"
51
12
6
1
"
50
6
"
will be found 51 cords.
8
1
"
55
6.1
a
EXAMPLE-An engine is working 25 horse power
10
11
"
60
71
66
required the number of cords the engine will consume
12
11
"
65
8
"
per day (12 hours.) Find 25 in the column marked
14
14
"
70
81
"
Horse Power," opposite to this number in the column
16
2
"
75
91
"
marked Cords," will be 3 cords.
18
21
"
80
94
"
ANTHRACITE COAL, use of in locomotives. See
20
21
"
85
10}
"
MANAGEMENT OF LOCOMOTIVES.
25
8
"
90
11
"
ANTIMONY. See METALS AND ALLOYS.
30
ANVIL See FORGING.
81
"
95
111
"
35
41
"
100
121
"
APPLE-TREE See WOODS, varicties of.
40
44
"
APRICOT-TREE See WOODS, varieties of.
APS. See WOODS, varieties of.
AQUEDUCT WIRE SUSPENSION, over the Allegheny River at Pittsburgh.-This work, recently
constructed under the superintendence of John A. Roebling, the designer and contractor, has supplied the
place of the old wooden structure which originally was built by the State of Pennsylvania at the west-
ern termination of the Pennsylvania Canal.
The council of the city of Pittsburgh, by whom, in consequence of an arrangement with the State, the
tolls on this aqueduct are of late received, and who are bound to keep the work in repair, decided on re-
building, and after considering various plans, adopted that of Mr. Roebling, and entered into contract with
him to reconstruct the communication, for the gross sum of $62,000, including the removal of the old
ponderous structure and the repair of the pier and abutments; a very small sum indeed for a work of
such magnitude. As this work is the first of the kind ever attempted, its construction speaks well for
the enterprise of the city of Pittsburgh.
The removal of the old work was commenced in September, 1844, and boats were passed through the
new aqueduct in May, 1845.
This work consists of 7 spans, of 160 feet each, from centre to centre of pier. The trunk is of wood,
and 1140 feet long, 14 feet wide at bottom, 16} feet on top, the sides 81 feet deep. These, as well as
the bottom, are composed of a double course of 21 inch white-pine plank, laid diagonally, the two courses
crossing each other at right angles, 80 as to form a solid lattice-work of great strength and stiffness, suf-
ficient to bear its own weight and to resist the effects of the most violent storms. The bottom of the
trunk rests upon transverse beams, arranged in pairs, four feet apart; between these, the posts which
support the sides of the trunk are let in with dovetailed tenons, secured by bolts. The outside posts,
which support the sidewalk and towpath, incline outwards, and are connected with the beams in a sim-
ilar manner. Each trunk-post is held by two braces, 21 X 10 inches, and connected with the outside
posts by a double joint of 2}X10. The trunk-posts are 7 inches square on top, and 7 X 14 at the heel;
the transverse beams are 27 feet long and 16X6 inches the space between two adjoining is 4 inches. It
will be observed, that all parts of the framing are double with the exception of the posts, so as to admit
the suspension rods. Each pair of beams is supported on each side of the trunk by a double suspension
rod of 1 fth inch round iron, bent in the shape of a stirrup, and mounted on a small cast-iron saddle, which
rests on the cable. These saddles are connected, on top of the cables, by links, which diminish in size
from the pier towards the centre. The sides of the trunk set solid against the bodies of masonry, which
are erected on each pier and abutment as bases for the pyramids which support the cables. These
pyramids, which are constructed of B blocks of a durable, coarse, hard-grained sandstone, rise 5 feet
above the level of the sidewalk and towpath, and measure 3 X 5 feet on top, and 4 X 6f feet at base.
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AQUEDUCT, WIRE SUSPENSION.
The sidewalk and towpath being 7 feet wide, leave 8 feet space for the passage of the pyramids. The
ample width of the tow and foot path is therefore contracted on every pier; but this arrangement proves
no inconvenience, and was necessary for the suspension of the cables next to the trunk.
The caps which cover the saddles and cables on the pyramids rise 3 feet above the inside or trunk
railing, and would obstruct the free passage of the tow-line; but this is obviated by an iron rod which
passes over the top of the cap and forms a gradual slope down to the railing on each side of the pyramid.
58.
The wire cables, which are the main support of the structure, are suspended next to the trunk, one on
each side; each of these two cables is exactly 7 inches in diameter, perfectly solid and compact, and con-
structed in one piece from shore to shore, 1175 feet long; it is composed of 1900 wires of fth inch thick-
ness, which are laid parallel to each other. Great care has been taken to ensure an equal tension of the
wires. Oxidation is guarded against by a varnish applied to each wire separately; their preservation,
however, is ensured for certain by a close, compact, and continuous wrapping, made of annealed wire,
and laid on by machinery in the most perfect manner. A continuous wrapping is an important improve-
ment, which, in this case, has been for the first time successfully applied.
A well-constructed and well-wrapped cable presents the appearance of a solid cylinder, which in
strength greatly surpasses a chain made of bars of the same aggregate section or weight. It is not only
the great relative strength of wire which renders it superior to bar-iron; but its greater elasticity, which ena-
bles it to support strong and repeated vibrations, adds still more to its value as a material for bridge building.
The extremities of the cables do not extend below ground, but connect with anchor chains, which, in a
curved line, pass through large masses of masonry, the last links occupying a vertical position. The bars
composing these chains average 11 inches, and are from 4 to 12 feet long; they are manufactured of
boiler scrap, and forged in one piece without a weld. The extreme links are anchored to heavy cast-iron
plates of 6 feet square, which are held down by the foundations, upon which the weight of 700 perches
of masonry rests. The stability of this part of the structure is fully ensured, as the resistance of the an-
chorage is twice as great as the greatest strain to which the chains can ever be subjected.
The plan of anchorage adopted on the aqueduct varies materially from those methods usually applied
to suspension bridges. where an open channel is formed under ground for the passage of the chains. On
the aqueduct, the chains below ground are imbedded, and completely surrounded by cement. In the
construction of the masonry, this material and common lime-mortar have been abundantly applied. The
bars are painted with red-lead. Their preservation is rendered certain by the known quality of calcareous
cements to prevent oxidation. If moisture should find its way to the chains, it will be saturated with lime,
and add another calcareous coating to the iron. This portion of the work has been executed with scrupu-
lous care, so as to render it unnecessary on the part of those who exercise a surveillance over the structure
to examine it. The repainting of the cables every 2 or 8 years, will ensure their duration for a long period.
Where the cables rest on the saddles, their size is increased at two points by introducing short wires,
and thus forming swells, which fit into corresponding recesses of the casting. Between these swells, the
cable is forcibly pressed down by three sets of strong iron wedges, driven through openings which are
cast in the side of the saddle.
When the merits of the suspension bar were discussed previous to the commencement of the structure,
doubts were raised as to the stability of the pyramids and the masonry below, when unequal forces should
happen to disturb the equilibrium of adjoining spans. It was then proved by a statistical demonstration,
that any of the arches with the water in the trunk, could support an extra weight of 120 tons, without
disturbance to any part of the work. In this examination, no allowance at all was made for the great
resistance of the wood-work, and the stiffness of the trunk itself. During the raising of the frame-work,
the several arches were repeatedly subjected to very considerable unequal forces, which never disturbed
the balance, and proved the correctness of previous calculations.
The stiffness and rigidity of the structure is 80 great, that no doubt is entertained that each of the
several arches would sustain itself in case the wood-work of the next one adjoining should be consumed
by fire. The wood-work in any of the arches separately may be removed and substituted by new ma-
terial, without affecting the equilibrium of the next one.
The original idea upon which the plan has been perfected, was to form a wooden trunk strong enough
to support its own weight, and stiff enough for an aqueduct or bridge, and to combine this structure with
wire cables of a sufficient strength to bear safely the great weight of water.
The plan of this work, therefore, is a combination which presents very superior advantages, viz. great
strength, stiffness, safety, durability, and economy.
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AQUEDUCTS.
39
This system, for the first time successfully carried out on the Pittsburgh aqueduct, may hereafter be
applied, with the happiest results, to railroad bridges, which have to resist the powerful weight and
great vibrations, which result from the passage of heavy locomotives, and trains of cars.
REMARK-The quantities in the following table are calculated for a depth of water of 4 feet, which
has been in the aqueduct ever since the opening. The depth contemplated was 31 feet; the greater
depth is at present required on account of the raising of the bottom of the canal by bars and sediment,
which have to be removed before the level can be lowered.
Table of Quantities on Aqueduct.
Length of Aqueduct without extensions,
1,140 feet.
Length of cables,
1,175 "
Length of cables and chains,
1,283 "
Diameter of cables,
7 inches.
Aggregate weight of both cables,
110 tons.
Section of 4 feet of water in trunk,
59 sup. feet.
Total weight of water in aqueduct,
2,100 tons.
"
"
"
one span,
295
"
Weight of one span, including all,
420
"
Aggregate number of wires in both cables,
3,800
Aggregate solid section of both cables,
58 sup. inches.
"
"
anchor chains,
72 64
"
Deflection of cables,
14 feet 6 inches.
Elevation of pyramids above piers,
16 feet 6 inches.
Weight of water in 1 span between piers,
275 tons.
Tension of cables resulting from this weight,
392 "
Tension of one single wire,
206 lbs.
Average ultimate strength of one wire,
1,100 lbs.
Ultimate strength of cables,
2,090 tons.
Tension resulting from weight of water upon 1 solid square inch of wire cable,
14,800 lbs.
Tension resulting from weight of water upon 1 square inch of anchor chains,
11,000 lbs.
Pressure resulting from weight of water upon one pyramid,
1871 tons.
"
"
"
one superficial foot,
18,400 lbs.
AQUEDUOTS, MODERN. Of the aqueducts erected within a comparatively modern period, we may
mention the following :-The aqueduct of Spoleto, constructed in 741 by Theodoric, king of the Goths.
to communicate with the town of Spoleto, situated on the summit of a mountain. It is one of the
handsomest structures of the kind, and remains entire to the present day. In crossing the river De La
Morgia, the channel-way is supported upon two tiers of Gothic arches, the lower containing ten grand
arches, and the latter thirty. The length of this arcade is 800 feet, the breadth 44, and the height 420!
The aqueduct of Caserta, built in 1753 by Charles IIL of Naples, is also an expensive and gigantic
structure, one of its arcades consisting of three tiers of arches, 1724 feet long, and 190 feet in height. In
France, that which conducts the waters of St. Clements and Du Boulidou to Montpelier, is perhaps the
must beautiful. It was built under the superintendence of M. Pitot, and required thirteen years for its
completion. The principal arcade is 90 feet high, and consists of two tiers-the lowest containing 90,
and the upper 210 arches. That of Arcueil deserves next to be noticed. It was originally built by the
Emperor Julian, A. D. 360, to bring water to Paris, and supplied the palace and hot-baths, but was
destroyed by the Normans. After it had been in disuse for 800 years, it was rebuilt in 1634 again
repaired in 1777; and fresh sums have lately been devoted to the same purpose by the city of Paris
The arcade over the valley of Arcueil consists of 25 arches, is 72 feet high, and 1200 feet long.
Of recent aqueducts, that of Lisbon and that of New York are the only two deserving notice.
The former, completed in 1738, is about three leagues in length, and in some parts of its course
has been excavated through hills; but near the city it is carried over a deep valley, for a length of
2400 feet, by several bold arches, the largest of which has a height of 250 feet, and a span of 115
feet.
AQUEDUCT, CROTON. The Croton river rises in Putnam county in three springs, whose rivulets
unite near Owentown; its water is increased by the surplus of several lakes, which collect the water of
the country by different small streams above and under ground. The principal branches being united
with the river, it receives still more water from a number of small brooks which fall into it from both
sides, till after many turns and windings it disembogues into the Hudson river below Tellers Point, 40
miles above New York.
It may be useful, in describing the engineering work, to know the geological formation of the ground
through which it passes, as well as of the adjoining regions. The predominant rock of the country is
gneise, a continuation of the formation which runs through the Northeastern States. Its quality varies
from the hardest granite suitable for every building material, down to a loose laminated mica-slate.
On the surface of the rock there are various impressions; in some of them large masses of white marble
are deposited, from which a superior building material is taken without much labor. The gneiss strati-
fication shows clear signs of some very violent revolutions; within the extension of one mile it dips in
every direction, and appears to have been forced up in some places through lateral pressure, by violent
concussions and shocks, and in some parts the layers are even broken. Here and there the gneiss-rock
lies exposed, or is covered in part as high as 50 feet with diluvium and alluvium mixed with boulders
of granite and trap, the latter proceeding from the right shore of the Hudson river, where it stands
upon red sandstone. The surface of the ground is traversed at short distances by every impediment
which can render the construction of an aqueduct difficult hills of 600 feet above the level of the sea
rise with every variety of slope, side by side with valleys of little or nothing above sea-level. The great
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AQUEDUCT, CROTON.
extension of this rock-ground offered excellent foundations, but the cutting it away and driving a number
of tunnels increased the expense very much.
Two different routes for the conduit-canal were proposed, the inland-route and the Hudson-route the
first commenced near the village of Mechanicsville, ran along the valley of Muddy-Brook, traversed the
ridge, went through New Castle valley, then the valley of Saw-mill river, and, by means of an aqueduct
bridge, crossed Harlem river to the city. From its commencement to the distributing reservoir in 38th
street, this line had an extension of 43 miles, retained a head of 117 feet, and a capacity of 27000000
gallons every 24 hours. The Hudson route started from the same point, ran along the left shore (look-
ing downward) of the Croton and the left shore of the Hudson river. The length of this line amounted
to 47 miles, and the estimate of cost was 4768197 dollars; on both the routes the water was to be
conducted in an arched aqueduct.
On the 5th of September 1833, the water was gauged by Mr. Douglass at Mechanicsville the produce
was 51522480 gallons every 24 hours. From some circumstances and from information collected from
persons living in the vicinity, he was induced to deduct one-fifth of this amount, which left 44120924
gallons of daily flow as minimum for all seasons. On the 25th September a gauge was made by the
Civil Engineer, Mr. Albert Stein. He found—
Gallons.
At Pine's bridge
57101068
One mile above Pine's bridge
49971686
Two miles above Pine's bridge
49276080
Three miles above Pine's bridge, at Mechanicaville
47959344
204608178
or 51077044 gallons every 24 hours as average, differing only by a few hundred gallons from the
Douglass statement. The observations and information gained, induced him to deduct 4 inches of depth
from the surface, in order to meet extraordinary droughts, which reduced the quantity as follows:
28731715 gallons
23186908
83004800
=
32707066
"
117630489
"
or 29407622 gallons on an average every 24 hours. During the uncommon drought, prevailing in
the summer of 1838-the work of the aqueduct being under construction already-the water in
the Croton river was remarkably low. Mr. Horatio Allen having made a gauge of the quantity of
water, there was found at one point 26886560 gallons, and at another 28738000 gallons; averaging
27562280 gallons every 24 hours, which came nearest to the Stein estimate. The quality of this water
exhibited, above all the waters of the neighborhood, the greatest purity and its mineral contents in
the gallon of 10 pounds or 57600 grains weight, were only 2.8 grains of carbonate of lime and magnesia,
which amounts not to the 20000th part of the whole; besides an admixture of 2 grains of vegetable
matter, which was supposed to fall on the bottom.
In company with the engineers Martineau and Stein, the water commissioners re-examined the ground
and the plans; in consequence of which, the place for the dam was fixed 6 miles lower than the point
proposed by Major Douglass. Difficulties arose between Mr. Douglass and Mr. Stephen Allen, the
chairman of the water commissioners, 80 that the friendly relations existing between these gentlemen
ceased in consequence; Mr. John B. Jervis was charged with the execution of the work, a practical and
experienced engineer, who had been previously engaged in the execution of state canals.
The line of the aqueduct was portioned off into 4 divisions of 10 to 11 miles extent each, by Mr. Jervis
the chief engineer. 1st division contained the dam, and stretched some distance below Sing-Sing, the 2d
to Cook's run, the 3d to Fordham Church, and the 4th to the distributing reservoir. The whole amount
of the work was given out in 99 Sections, one after the other, under contract.
THE CROTON Dam-At the above-mentioned point, the dam was erected in order to raise
the water, and to form the Croton lake. Fig. 61 shows the profile of the river. At first a length
of only 90 feet was given for the dam B, and this part was erected after the profile of Fig. 59, with a con-
struction similar to that of Fig. 62, extending then only from a to b, Fig. 61, occasion for which was given
by the rock lying here affording a good foundation: the remainder of the river profile to d, was to be
filled with an earth embankment. A considerable freshet, however, carried away this embankment when
partly completed, and it was resolved to extend the stone dam 180 feet further, to c. For the erection
of this part, A, Figs. 61 and 62, the bottom of the river was cleared from mud and boulders, and the piers
C and D, of 12 inch hemlock timber, successively built up; the walls were connected together by ties, and
filled with stone closely packed in; the top was covered with six-inch plank of white pine, and treenailed
upon this planking, the timber-piers F and G were erected, but only F covered with plank. While erect-
ing those piers, the space E was filled with concrete, and the piers near the top connected with ties.
Both these piers, together with their filling of concrete, being the armature of the dam, served at the
same time for a coffer-dam against the water above. Against G, another timber pier was in like man-
ner constructed, with but one timber wall; in place of the other, anchors of round timber were laid in,
and with the ties joggled together. The timber of these piers is of hemlock, 12 inches by 12, the ties of
white oak, 7 inches thick at the smaller end, framed with single dovetails 4 inches thick, Fig. 65, and
fastened with one-inch treenails, which are placed 10 feet from centre to centre. The pier-timbers, Figs. 63
and 66, are treenailed 80 inches deep, with 2-inch treenails of white oak. These nails are sometimes put
nearer together, and the ties likewise. The planking is of white pine. When the timber piers had
reached a certain height, the piers KK, of four compartments, were put down, two of which, the nearest to
low water, were packed out with stone; the two others were filled with concrete, and formed the coffer-
dam against the water below the dam. The courses were of 12 by 12 inch hemlock; the ties of oak, 8
Digitized by
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41
Granite
1
59.
61.
a
B
c
Earthd
B
Digitized by Google
Tunnel
puv
Alluvium with boulders
Aqueduct
CROTON LAKE
gnelss rook
b
55
duct
Profile at B
Radius
of
60.
and
Original bottom
66.
Secondarydam
ofCroton-river
Fore Embankment Profile at A.
Itm
AQUEDUCT, CROTON.
Elm
White oak
6
63.
W.oak
2
White
W.oak
W. elm
64.
White
clm
&
62.
oak
E W. oak
65.
y-ss
&
Lak
embankment Fore of earth
Rear of Aprons
67.
Top line of Secondary Dam
Bond of stone infaceofweir
Dead water
3m 35
SCALE.-One inch=20 feet. One inch=8 feet.
Natural ground
of
24
42
AQUEDUCT, CROTON.
inches at the smaller end, and 6 feet apart from centre to centre the treenails of the equared timber the
same. The uppermost of them are made of elm and white oak, treenailed every 3 feet, 30 inches deep,
21 inches in diameter. The upper ties, Figs. 64 and 66, are of elm 12 inches square; to this course of ties
a bed timber of white elm is joggled and secured by iron screw-bolts, Fig. 66. Across these bed timbers
or caps, an apron-planking of 6-inch elm is fastened by 1}-inch locust (robinia pseudo acacia) tree-
nails of 13 inches in length. Against the rear of this timber pier the one marked L was erected;
against the back-water only, it has a regular timber wall, Fig. 63: the ties are secured by anchora. A
part of the apron planking of this pier is laid horizontally in connection with the apron of the pier K; the
remainder is put three feet lower, Fig. 62. After the pit had been laid dry by pumps, the ground and
the space at f were filled in with concrete and levelled off. On this bed the body of the dam was by
degrees erected of hydraulic stone-masonry, according to the bond, Fig. 67, and the courses of face-stone
for the weir laid down. This face-work is of granite, cut with such closeness as to allow the stone to be
laid with a joint not exceeding three-sixteenths of an inch. The masonry is laid in horizontal courses
to 3 feet from the extrados of the face-work, where it is in courses corresponding with the radii. In
front of the lip of dam below the head-water, a fore-embankment, Figs. 59, 60, and 62, was formed of
earth, and its upper part secured with a dry stone-pavement 2 feet thick.
In the part of the dam first erected, B, Fig. 61, at b, and Fig. 60 at b, a waste-weir is constructed, in
order to draw off the water of the lake from a greater depth; it consists of a well with culverts having
two sets of gates, all of which are protected with a small stone-house, Figs. 60 and 61, at b; which can
be reached by the bridge B, Figs. 59 and 61.
At a distance of 300 feet from the lip, a secondary dam, Figs. 59 and 60, is constructed it is erected
of round timber, filled up with dry stone. The object of this secondary dam is to divide the head of
water, and by means of the water-basin formed by it, to break the body of water running over the weir,
and to keep the wood-work of the timber-piers K and L, under water. Near the left shore a waste-
weir is constructed in this dam, in order to let off the water from the basin when required.
By the construction of the Croton dam the water was raised 40 feet, whereby the river passed its
shores and formed the Croton lake: this is the collecting-reservoir of the aqueduct, containing in it, at
a depth of 6 feet, 500000000 gallons of disposable water, above the level that would allow the aque-
duct to discharge 35000000 gallons per day ;-sufficient for 1750000 inhabitants, at the rate of 20 gal-
lons daily per head, including manufactories, shipping, watering streets, gardening, baths, &c. The flow
of the Croton is about 27000000 gallons in 24 hours, at the lowest stages, which continues, with mode-
rate rains, from two to three months in the year. Whenever the wants of the city may require the
above-mentioned amount, it will be necessary to draw from those 500000000, daily, 8000000 to make
up these 85000000. The amount of the reservoir would thus afford a supply for 621 days. Never has
the water in summer been 80 low. The supply of the Croton from its daily flow, aided by the reser-
voir, may therefore be taken, with great confidence, at 85000000 gallons; and when the day arrives
that will require a larger quantity, it may be obtained by constructing other reservoirs further up the
stream, where there are abundant facilities for such purposes.
PROFILE OF THE AQUEDUCT.-At the first consideration of the adopted plan, to conduct water from
the Croton river, an open trapezoidal canal was proposed. The flow of the water over earth and rock
might, however, impregnate the conduit-water therewith;-and as a good deal might sink into the bot-
tom, it became necessary to make the bed waterproof; to do this with tight earth seemed insufficient,
though brick with concrete under it might answer. The open canal remained, however, exposed to the
sun and to evaporation, as well as to the wading of cattle, to bathing, and to being filled up with earth,
boulders, and snow washed in; and might, in fine, freeze out in winter; it became necessary, therefore,
to cover it, as had been found indispensable already, at deep-cuts, and in the vicinity of villages. A
protection with a kind of wooden roof was some time under discussion, (seeming economical,) having
the deep-cuts and tunnels arched. This mode of roofing, however, did not seem impenetrable to frost
and heat; it was resolved, at last, to arch the whole, notwithstanding the great expense.
The artificial Croton lake stretches more than 5 miles on the line of the original bed of the river,
which makes the total length of the whole work amount to 50 miles.
The regulation of all the measurements in heights and depths was taken from a grade-line or planum
which is 7 inches below the intrados of the inverted arch at the bed of the aqueduct, being the base-
line or basis-surface of the aqueduct-masonry, in cuttings into the natural ground.
LENGTH, INCLINATION, AND GRADE-The fall of the aqueduct on the continent is 0.021 per hundred,
or 1.1088 feet per mile. The roofing-arch follows accurately this inclination, except a distance of 2276
feet next the dam, which runs horizontally at the height of the lip of the dam. At the entrance, 2.93 feet
were added to the height, which brought this to 11 feet 5 inches in the clear, (Fig. 62.) From the
lower intrados the inclination is 0.0118 per 100, or 0.59664 feet per mile, at a distance of 4.949 miles,
where it meets the general inclination and the profile of the aqueduct, as shown in Figs. 68, 69, 70
This arrangement, which, in a certain way, can be considered as an extension of the lake. renders it pos-
sible to draw water from a depth of 11 feet 5 inches, and to carry it, under influence of its head, with
less fall, over this distance. At the level of the lip of the Croton dam the aqueduct has still a capacity
to draw off 85000000 gallons every 24 hours, as experiment has shown.
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AQUEDUCT, CROTON.
43
Table of Lengths and Inclinations.
Distances in
Fall in feet.
Miles.
Feet.
From the dam to the meeting of the general inclination
4.9490
26130
2.9507
From here to Harlem river the general inclination 0.021
per 100 or 1.1088 feet per mile of 5280 feet
27.9316
147479
30.9700
At the aqueduct-bridge of Harlem river to the general
inclination 2 feet are added, the water being carried
over in pipes by a siphon of 12 feet
0.2750
1450
2.3450
To Manhattan valley the general inclination of 1.1088 feet
per mile
2.0140
10635
2.2334
Across Manhattan valley the water passes in a siphon of
109 feet head, for that reason 8 feet are added to the
general inclination
0.7917
4180
3.7783
From here to the receiving-reservoir 9 inches per mile
2.1727
11471
1.6295
From the influence-gate of this reservoir to its effluence-
gate
0.1720
908
0.0000
To the distributing-reservoir the water is carried in a si-
phon by pipes; for the entire distance
2.1760
11489
4.0000
Distributing-reservoir
0.0800
420
0.0000
These 47.9069 feet form the fall at the bottom of the aque-
40.5620
47.9069
duct; at the head this bottom is
11.4633 F.
below the surface of the lake, but only
8.2000 "
at the discharge in the receiving-reservoir
which gives
3.2633 64
3.2633
difference, added to the fall at bottom; this makes the
entire fall, or the accurate difference between the surface
of the Croton lake and that of the distributing-reservoir
51.1702
When to this extension of the aqueduct that of the large
mains is added, which is about
4.0000
we have the following as the entire length of aqueduct
from its head to the distribution of the water, viz. :-
44.5620
CONSTRUCTION OF AQUEDUOT-CANAL-Where the masonry of the aqueduct is cut in level ground or side-
hills, a course of concrete 3 inches high is laid under the whole extent of masonry under the
extrados of the inverted arch, as high as the shape of the extrados required. Where water-veins
were met, and in loose ground, or where the depressed ground made foundation walls necessary, the
concrete bedding was put 12 inches high as broad as the clear width of the aqueduct; but under the
side walls only 6 inches. In both cases each of the side walls was carried up 13 inches high perpen-
dicularly, by which the spring-line of the inverted arch was reached; after this the inverted arch was
turned 1 a brick 4 inches thick, the stone part of the side walls carried up 4 feet high, and on both
sides plastered 1 inch thick with hydraulic mortar. When these walls had set, the inner facing, I a
brick 4 inches thick, was carried up; at last the roofing-arch, 1 brick 8 inches thick then the span-
dril-backing, over which and the upper part of the extrados, plaster of i inch thickness was laid on and
smoothed off with the trowel. Where suitable stone was to be had near, the side walls could be car-
ried up; also the roofing-arch, which in this case was turned 12 inches thick; this, however, has been
carried into execution in but few instances. The courses of masonry were levelled off every 12 inches,
and no stone put in which reached through the wall or raised over the course of 12 inches; granite,
or gneiss of the most sound quality, was used.
The hydraulic mortar at tunnels, deep-cuts in earth and rock, had the proportions of 1 part cement
to $ sand upon foundation-walls, however, 1 part cement to 21 sand in volume; the same proportion
for concrete. The sand for concrete, containing coarse and fine grains, was first mixed with water, then
there was added to it from 2 to 21 broken stone of the size of 11 inch, or the same amount of coarse
gravel, and worked till the mass became uniform, and the broken stone completely covered and bedded
in the mortar. Immediately after this preparation the concrete was laid and settled with a stamper
till the surface had the appearance of an even floor the courses were laid not over 6 inches thick.
For brick masonry the proportion of cement to sand was 1 to 2; the mortar for vertical joints was put
to the brick before laid, the brick forced into its bed in such a manner, that from horizontal and vertical
joints the mortar readily is forced out like sausages; the superfluous mortar was then taken off and the
joints smoothed immediately: only bricks of superior quality were admitted, No. 1 for the inverted
arch and the facing, No. 2 for the roofing-arch.
CULVERTS.-In order to carry off rivers, creeks, and field-waters, underneath the aqueduct, culverts
were constructed at a suitable depth. Their fall or inclination was 1 in 20; and where the upper end
happened to be below the surface of the ground, generally the case at side-hills, a well was constructed,
Figs. 76 and 79. The culvert, Figs. 79, 80, and 81, is one of the smallest dimensions, with bottom and
roof of stone alabs; that of Figa. 76, 77, and 78, is a large one, bottom and roofing are of smooth, well-
wrought stone, the side-walls only faced with it, while the backing of this face-work is of rough masonry.
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44
AQUEDUCT, CROTON.
Tunnel
68.
Bulk-head
LipolDam
a
11'5"
*
*
F
70.
ton lake
M
&
*
69.
Agreduct
&
6
71.
Aqueduct
&
Regulating gates
Guard-gates
Screen Enzme
Tunnel
20
I
180 long
72.
SCALE.-1 inch = 40 feet.
Digitized by Google
AQUEDUCT, CROTON.
45
In the body of the foundation-wall of the aqueduct, an arch of dry stone without mortar was rolled over
the extrados of culvert, Fig. 78; after this the foundation carried further up. The fall-well at the
arched culverts is round in plan, Fig. 77.
THE GATEWAY.-From the effluence of the lake, Figs. 59 and 61, a tunnel is cut through solid rock,
180 feet in length. It has no facing of masonry, and in dimensions is kept somewhat larger than the
general aqueduct, only below the gateway, Fig. 70, it takes the dimensions as marked, Fig. 62, except
the height, which is here greater. The ground is uncommonly favorable for the construction of the
gateway, offering roek-foundations throughout. As shown, Fig. 71, the channel "of the aqueduct is
widened, and the water runs through an arch in the bulkhead a a, then passes the screen-frame, a set of
guird-gates, and a set of regulating gates. The screen, formed of oak slabs, six inches by one, allowed
a quantity of fish to pass through the one-inch spaces into the aqueduct. In order to prevent this, a fine
brass netting was put over the screen, through which only very small fish could pass; to prevent which
other artificial preparations will be required. Below the wall with the regulating gates, the width of
the water-way is reduced to the general width of the aqueduct, by an ogee curve, in order to let the water
into the proper aqueduct without any loss of fall.
The guard-gates with their frames are of cast-iron, made as shown in Fig. 97 a is the frame lined with
metal. The sill is marked here let in stone, but in the case under description it is cut something into
the wooden floor; b is the shover with the consols c c through which the wrought-iron rod dd passes-the
latter has a screw cut at its upper end ec is a nut, which is let into the caps and screwed. By
turning right or left with a key put on the die, the rod rises or lowers, and the gate is opened or shut.
On account of the considerable length of the rod, the guides k k, Figs. 69 and 70, are put on they consist
of cases of wrought-iron, leaded into the stone of the wall. The regulating gates with their frames are
of gun metal, in order to obtain a superior tightness. The caps ff, Fig. 70, are secured upon the saddles
by bolts. In turning to the left the female, whereby the shover is raised, the saddles with the caps
press upon the base and are kept closer and closer upon their bed; in screwing right, however, they press
upward. To prevent their loosening and lifting, the screw-bolts n n n are put in; they reach down through
two courses of stone, and there they are bent; some of them are secured to the caps of the screen-frame.
In shutting the gates by turning to the right, the bolts n n secure the caps ff to their places and prevent
their lifting. The masonry in all parts of the gateway is of rough gneiss in hydraulic mortar, faced with
well-hammered stone the partitions between the gates are of cut stone. To keep the gates and utensils
secure, a stone house is erected over the gateway.
LINE OF AQUEDUCT-Having left the gateway, the aqueduct makes its way upon the left bank of the
Croton river. After a course of one mile, it crosses Lounsberry's brook, over a culvert of 6 feet in width,
66 feet in length, the bottom of which lies 44 feet below the top of the back-filling of aqueduct. After
crossing some little brooks with small culverts, the line leaves this river, having followed it for 5 miles,
turns to the left and crosses the valley of India creek 6 miles from the dam; the culvert for the passage
of this stream is 8 feet wide, 142 feet long, and its bottom is 58 feet below the top. A little distance
further, the aqueduct is tunnelled through two hills of solid rock. The first passage, called Benvenue farm
tunnel, is 720 feet in length; the second, Acker's brook tunnel, is 116 feet long. Half a mile further is
another tunnel of 276 feet in length, called Hoag's hill tunnel, cut through rock. From here to Sing-Sing,
several small valleys and ravines of from 20 to 32 feet in depth are crossed by the aqueduct. Immediately
after the last one, there is another tunnel worked through rock, called Sing-Sing tunnel.
SING-SING KILL BRIDGE-Was commonly called, while in construction, the passage of the aqueduct
across the valley of the Kill river. Although the Kill is merely an unimportant brook, by frequent
freshets it has worn out a large chasm, the depth of which from the top of the aqueduct to the rock
bottom is 82 feet; the width measured at the top is 536 feet. Parallel to the river runs a street of the
village of Sing-Sing, over which an aqueduct bridge of 20 feet in width was constructed; a little further
the line of the aqueduct cut off the dwelling-house from the rest of the farm of Mr. Sing, where a pas-
sage-way 7 feet wide was constructed. Across the stream an arch of 88 feet span was required. The
abutment walls of this bridge are 20 feet thick, on solid rock-foundation. The arch is constructed over an
half oval, 33 feet in height, 4 feet thick at the spring-line, and 3 feet at the keystone; the granite and
gneiss for it was cut with much accuracy, not allowing the joints to be over three-sixteenths of an inch
thick. The spandrils were carried up solid, sloping upward, thence with hance walls and alternating
openings, till 3 inches over the highest point of extrados: these openings were arched over with half a
brick. Across those openings, the hance walls were connected together by bond stone. On the top of
the small brick arches, a rubble masonry of 6 inches in height was laid, and the whole levelled off; on
this the concrete course of 9 inches height to the extrados of the inverted arch of aqueduct. As far as
the clear width of the bridge arch and its abutments extended, the construction of the aqueduct was 80
altered, that the side-walls were carried up 5 feet high instead of 4, as in ordinary aqueduct, and the
arch was turned over a segment of 7 feet 7 inches long, 2 feet 81 inches high. Bottom and side walls
were provided with a lining of cast-iron in form and dimensions, worked in with the masonry whereby
the aqueduct was rendered absolutely water-tight above these constructions. The same iron lining was
applied also at the before-mentioned street bridge. Between the attic wall and the side wall of the
aqueduct, spaces were left, covered over, above the attic wall, carried up in connection with the side
walls of the aqueduct, and covered with a coping stone, the whole then filled over with earth. The
spaces serve not only for protection against frost from without, but also for carrying off the water falling
from the sky on the back-filling, down into the hollows. Upon the extrados of the bridge-arch, the
drainage water runs over the tangental surface of the spandril-backing into the dry foundation wall.
The surface over which the water drains is well plastered with hydraulic mortar. The exterior masonry
of both the bridges is of well-hammered stone. Throughout the structure hydraulic mortar was used.
For the distance of aqueduct between the bridges and back of them to the side-hills, the rock bottom
was prepared with steps, and a foundation wall of dry stone-masonry carried up The exterior faces of
some thickness into the wall were laid in hydraulic mortar, and the joints pointed with the trowel.
Digitized
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46
AQUEDUCT, CROTON.
76.
Grade-line
Turnnike
/
of
Aqueduct.
Slope
1to
road
/
Natural ground
Dectivity 11.20
78.
77.
&
79.
Slope
3th2
3th2
Grade-line
of Aqueduct
Natural ground
NON
81.
80,
88.
90.
14:
4'
Ton of
Backlilling
220
Grade
line of Aquiduct
91.
89.
SCALE.-1 - inch - 40 feet.
Digitized by Google
AQUEDUCT, CROTON.
47
CONTINUATION OF THE LINE OF AQUE-
73.
Ducr.-Below some streets running across
Sing-Sing, the aqueduct proceeds further
on for a mile, on quite favorable ground,
Grade
line
and when on the land of the State prison
of
Aqueduct
farm, it enters into the great State prison
farm tunnel, made 416 feet long, partly in
rock, partly in earth. At some distance
further, it is met by the small State prison
farm tunnel, 375 feet, in earth: 91 miles
from the dam, after having passed Hale's
brook tunnel of 260 feet in length, the
aqueduct crosses the valley of Hale's
brook; its culvert is 6 feet in width, 131
feet long, and 49 feet below the top of the
back-filling of the aqueduct. One mile
further, the line crosses Rider's brook, over
a culvert 100 feet long, 6 feet wide, and
74.
34 feet under the top of the aqueduct: 10
miles from the dam, the aqueduct crosses
over the highway leading from Sing-Sing
to Tarrytown by a bridge of 20 feet span.
Grade line
Proceeding further on, the aqueduct en-
counters some high land, through which a
tunnel of 186 feet is driven; it is 11} miles
from the dam, designated Austin farm tun-
nel From here the ground has various
depressions of from 20 to 30 feet under
the top of the aqueduct.
At Mill river, 18 miles from the dam,
the crossing-work is imposing. The de-
pression of the valley is 87 feet below the
top; the culvert or aqueduct bridge is 25
feet in width and 172 feet in length. In
the extension of the next two miles, in the
vicinity of Tarrytown, at five valleys in
75.
succession, small culverts of various dimen-
sions are constructed; then the aqueduct
passes a tunnel of 246 feet in length, most-
ly through rock, called White Plains tun-
nel; then Requa's brook is crossed, over a
culvert of 25 feet below the top; and after
this the classical ground of Washington Irving's farm and Irving's run, the latter with a small culvert
The next structure is at Jewell's brook, and its ravine, 17} miles from the dam; the culvert is 6 feet
wide, 148 feet long, 62 feet below the top. A farm-road which could not be removed, was made to run
under the aqueduct at a heavy expense; its arch is 14 feet in width, 141 feet long. Across Wilsey's
brook, 181 miles from the dam, the culvert is 49 feet below the top, 6 feet wide, and 137 feet long.
Half a mile further there is a tunnel near Dobbs' Ferry, 262 feet, driven through earth, and designated
Dobbs' Ferry Tunnel. Crossing Storms' brook, the depth of culvert is 40 feet, the clear width 6 feet,
and the length 187.
From here the aqueduct passes several small valleys of from 10 to 15 feet in depth. At Cook's run
the culvert is 4 feet wide, 132 feet long, and its bottom is 42 feet below top of aqueduct. Dyckman's
brook, 22 miles from the dam, has a culvert of 8 feet in width, 120 feet in length, and is 35 feet below
the top of back-filling. Then the line crosses various unimportant valleys and creeks, with small
culverts, and arrives in the vicinity of the village of Yonkers, where, on account of the greater inland
extension of low ground, an abrupt curve to the left was required, followed at a short distance by
another to the right. The aqueduct passes through the Sawmill river tunnel, which is 684 feet, driven
partly through earth, partly through rock; then it crosses the river itself, over which a bridge of two
arches of 25 feet each has been erected. Fig. 73 is the cross-section of aqueduct at this point, with the
longitudinal section of bridge; Fig. 74 the cross-section of bridge with the longitudinal section of aque-
duct; and the last, Fig. 75, is the horizontal projection of one of the flanks; close to it is the passage for the
turnpike-road, 20 feet in width, arched over a semicircle. The next work is a culvert over Nodine's
run; after which a hill of considerable height is encountered, behind which the valley of Tibbit's brook
comes in the way. The tunnel under this hill is 810 feet long, driven through solid rock, and called
Tibbit's brook tunnel. The culvert for the brook is 6 feet wide, 107 feet long, and its bed is 40 feet
below the top of the aqueduct: it is 26 miles from the dam. At some distance several small brooks
are crossed one is O'Brien's run; the largest is Acker's brook, which passes 87 feet below the top of the
aqueduct. The last two miles of the line are very nearly straight, the high land offering 80 favorable
ground, that the upper filling of the aqueduct just disappears under the surface. Here the aqueduct
arrives at the strait which separates Manhattan Island from the continent.
HARLEM RIVER BRIDGE-The valley of Harlem river slopes down from the before-mentioned high
land, at a point which is 33 miles distant from the Croton dam, first at 20 degrees, to a piece of table-
land 25 feet above tide-water, stretching over a distance of 800 feet, whence, by a second slope, it
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48
AQUEDUCT, CROTON.
reaches the water's edge. The tide-water has here a width of 620 feet. The bank of the island being
of solid gneiss-rock, rises with a slope of 35 degrees to the height of the top of the aqueduct. The slope
of this rock below water, as far as it could be examined, is steeper, and disappears under a deposite of
mud mixed with sand and boulders. It is supposed this rock has connection with that of the opposite
shore. In the basin formed by its depression below the strait is deposited a mass of white marble, Fig.
100, upon which the gneiss and alluvium of sand, mixed with pieces of rock and boulders, are found, upon
which mud is deposited, consisting chiefly of vegetable matter.
At first it was intended to carry the conduit-water over the valley in a siphon, through iron pipes,-on
the side of the continent, following the surface of the ground to the water's edge, across the water of the
river upon a stone embankment, from the centre of the river, ascending to that point of the island where
the aquelluct starts again. Through the body of that part of the embankment, next the island bank
which is sloping up, an arch of 120 feet in width, 60 feet high, was intended, through which a passage
was to be kept open for navigation with sloops and schooners of 200 tons burden. The execution of
this work was already contracted for, the dredging-machine in operation, when the landholders of both
the banks of the river started a lawsuit against the measure; and an act from the legislature of the State
was obtained, according to which, the aqueduct was to be carried below the bottom of the sea, or above
its surface at such a height, that openings of 100 feet above high-water, 80 feet in width, had to be left
in order to carry on the navigation. Notwithstanding estimates and comparisons of the two methods
showed a surplus in cost of 200,000 dollars for the latter, its erection was preferred.
This bridge has 15 arches, 8 of which are 80 feet in width each, by 100 feet in height above flood-tide,
placed in the water, and upon both the shores 7 arches of 50 feet span each the two abutments were
founded on the gneiss rock, three upon the marble, seven on piles, the rock being without reach below
the latter. With this arrangement, the conduit-water was carried across to the island in a siphon of 12
feet depression.
The manner intended of carrying the water below the bottom of the sea should here be mentioned.
Following the slopes of the banks and the valley, 4 pipes of 8 feet diameter each, were to be laid 4 feet
under the surface of the ground, below the bottom of the Strait; 2 tunnels, parallel to each other, 12 feet
wide, 8 feet high each, 12 inches thick at bottom arch, put upon concrete, side walls and centre wall 4
feet thick each, roofing arches 16 inches thick; the extrados of both these arches covered with a course
of concrete of 2 feet thickness, and the whole structure, top and sides, covered again with a stone pave-
ment 12 inches thick, set in hydraulic mortar; the stone pavement was kept 24 feet below low-water.
Each of the tunnels contained 2 pipes; the tunnels were provided with entrances, in order to examine
them. It was intended to carry out the work by means of a coffer-dam on each side. The estimated cost
was 636738 dollars.
In order to reach the foundation of every pier for the high bridge, a coffer-dam was put down, the
coffer or box made for each of the piers of such a height as the depth of water at its site required, to-
gether with the thickness of the mud-deposite, and 8 feet border above high-water.
In order to take the water out of the aqueduct, and let it into the pipes, and after passing over the bridge,
re-discharge the same into the aqueduct, 2 gate-chambers, a and b, Fig. 100, are placed. Fig. 113 shows the
ground-plan, Fig. 112 the longitudinal section, and Fig. 111 the cross-section of the influence gate-chamber,
(entrance into the siphon;) c c is a basin, the bottom of which is level with the deepest line of the in-
trados of the inverted arch; dd are the gateways, ee the two pipes; the influx of the water can be
regulated by the two cast-iron double gates k k; f h is a waste-weir, whereby the waste water or the
whole content of the aqueduct may be let off; f is the gateway, g the waste-weir well, h the sewer.
The construction of the latter for the first 80 feet in length, is shown by Fig. 115; following the slope down-
ward, it is funnelled into the shape and construction of Fig. 114, which leads to Harlem river. Fig. 111
is the section of gateway for the waste-weir; Fig. 112 the elevation of front with the gates 11. All
the gates are of shape and construction as shown at Fig. 69. The rod-caps of waste-weir are connected
by the bolts m n, Fig. 111, with the consols n; but the rod-caps of the gateways by the bolts m n, which
are kept down and secured in the pier below, by the crosspiece n. Over the entire structure, a stone
building is erected, arched with bricks, and covered with 3-inch greywacke slabs. The effluent-gate b,
Fig. 111, at the island extremity of the bridge, is of the same arrangement in reversed order, but without
waste-weir; it receives the water from the pipes of the siphon, and discharges it again into the aqueduct.
Several times the question has been asked, why this bridge, being in a certain way considered a con-
struction of luxury, has not been carried up to the full height, reaching the water-line of aqueduct, with
the construction of the latter as upon the Sing-Sing Kill bridge 1 The pipes could have been spared the
erection of the gate-chambers rendered needless; and what is most important, 2 feet of height had been
saved, 117 feet head being left in the city, instead of 115. The reply may be :-a greater height of
the structure would have required a larger and more compact model for the piers, or a more careful
choice of material, and a more costly workmanship of the same; also a greater height for the attic walls
upon the bridge arches; and in fine, the construction of the aqueduct itself with iron lining. All this, with-
out doubt, would have accumulated the cost by 75000 dollars, a sum of some moment in the cost of the
water-work. Considered as a monument, the bridge, as above constructed, has a sufficient height.
The beginning of the construction of this bridge had been greatly delayed. It was desirable to use the
aqueduct sooner than the bridge possibly could be finished. Down the descent of the valley, then upon
the embankments enclosing the coffer-dams-which by degrees had formed an unbroken embankment
across the salt-water strait-then up the island-shore to the aqueduct, a 36-inch pipe was put down,
through which the conduit-water provisionally was led across the valley, and the aqueduct opened on
the 4th of July, 1842. The construction of the bridge went on but slowly.
CONTINUATION OF THE LINE OF AQUEDUCT.-A short distance from the effluence-gate the aqueduct
passes over a ravine of 30 feet in depth, immediately after which a tunnel had to be driven 234 feet
through solid rock. This lies about 331 miles from the dam, on the land of the deceased Monsieur
Etienne Jumell, on that account called Jumell tunnel. Close by this tunnel is a ravine of 38 feet in
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b
100.
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MANHAT ISLAND.
Mica
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AQUEDUCT, CROTON.
Elevation of Scaffold.
105.
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ter
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bridge
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49
50
AQUEDUCT, CROTON.
111.
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114.
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AQUEDUCT, CROTON.
51
depth, and another 43 feet deep. Proceeding further 341 miles from the dam, the aqueduct enters into
the line of 10th Avenue. Without any obstacles of consequence, it proceeds hence to the vicinity of Man-
hattanville, and 35 miles from the dam passes through Manhattan-hill tunnel, the longest of the whole
line-worked 1215 feet through rock.
MANHATTAN VALLET.-Having left the tunnel, the ground slopes down to a depth of 105 feet, and
rises up again to grade-line; measured here, the length amounts to 4180 feet. For conducting the water
across this valley, first an aqueduct of arcades was proposed, with arches of brick supported by piere
of rough stone-masonry, and the aqueduct upon these in its common shape. This method of crossing
would have preserved 3 feet of head-pressure for the conduit-water, but at an expense of $1200000,
while the passage in pipes cost only the fifth of that sum; this was a matter of some moment, and it
was concluded, therefore, to make use of 4 pipes of 36 inches each. At the end of the last-mentioned
tunnel an influent-gate, similar to that of Fig. 112, was erected, only of a greater width of basin-4 pipes
being required; otherwise of the same arrangement, leaving out the waste-weir. At the brow of the
opposite height, called Asylum-hill, is the effluent-gate, of the same construction entirely with the in-
fluent-gate; it receives the conduit-water from the pipes, and lets it into the aqueduct again. Between
83.
8
c
Grade
line
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85.
84.
m
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86.
87.
d
those two gates the siphon is placed, the pipes of which are partly laid in the ground; and where de
pressions of the ground occur, upon an embankment of earth, throughout covered with earth 4 feet high
In order to empty the pipes of the siphon when required, in cases of repair or removing deposites of san
at the deepest depression of the valley, here, just in Manhattan-street, provisions were made for a waste
weir for that purpose at each pipe; waste-pipes were put in; those pipes pass through the stop-cock vault
and discharge into the waste-weir well. When one of the pipes is to be emptied, both of its upper ends
are closed first by the respective gates in the gate-houses, then the stop-cock in the stop-cock vault
drawn open; the content of the pipe makes now its way through a pipe into a sewer. which about 2000
feet from here discharges into the Hudson river.
CONTINUATION OF THE AQUEDUCT-LINE-The declivity of the aqueduct being from here only 9 inches
per mile, the water rises back as far as this from the receiving reservoir, which is merely 2.1727
miles off. To the thickness of the side walls of the aqueduct, by degrees, 4 inches have been added,
making in all, 3 feet below, and 2 feet 4 inches at the spring-line; in the same way the walls were car-
ried higher up to 11 feet above the spring-line of the roofing-arch. A short distance from the effluent-
gate the line goes through its last tunnel, called Asylum-hill tunnel; this has a length of 640 feet,
mostly broken through rock. Further on, for the grentest part of a mile, it was necessary to construct
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AQUEDUCT, CROTON.
the aqueduct thus, that its sides and back-filling reached the height of 80 feet; at the end of this, for a
little distance, the ground rises again to such a height that the upper-filling of the aqueduct just disap-
pears below it, then another valley comes in the way.
CLENDENNING VALLEY is the name given to the depression of ground which stretches across the high-
lands of the island. The most favorable passage for the aqueduct is offered by in ne drawn 150 feet
west from the axis of 9th Avenue, to which the aqueduct-line, coming from the 10th Avenue, is con-
nected by an ogee-curve. The valley here has a length, or rather width, of 2000 feet, measured from
the commencement of the upper-filling of the aqueduct, at the brow of the hill, to its disappearance on
the opposite side; its greatest depth is 50 feet below the upper-filling. Looking on the map, it shows
that this part of the island is laid out in streets and blocks. At this place it was designed that the
streets, after being cut through and opened, should cross over the aqueduct; but, under such a con-
siderable depression of ground as this, it was not practicable; and it was concluded to pass 6 of
d
92.
94.
i
93.
-
95.
d
d
96.
97.
Stone
98.
a
b
99.
Brick
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o
3
these streets, viz., the 101st, 100th, 99th, 98th, 97th, and 96th, underneath. The first 5 of these streets
are 60 feet wide; but 96th, being a principal street, is 100. For their passage aqueduct-bridges were
applied, of 3 arches each for the first 5; a main arch 30 feet in width in the centre for the road-way
and two side arches, for the sidewalks, of 9 feet span each, over 101st and 97th streets; but of 10} at
the bridges over 100th, 99th, and 98th streets. During the construction of those bridges it was thought,
by the new Water Commissioners, only some of those bridges might be required for passage for the
space of 50 or even 100 years, in consequence of which the passages for 101st, 97th, and 96th streets
were beforehand left out; the bridges for 100th, 99th. and 98th streets will then be spoken of here.
The dimensions of the different parts of these bridges are the same among all, with exception of the
height of the pier-shafts only, which is determined by the various levels of pavement in the streets, but
making only a difference of some inches. The foundation of all the piers is placed partly on rock,
and partly on alluvial ground ; the piers themselves, as well as the arches, being constructed of gneiss
rock; the former of well-hammered stone, the latter of cut-stone. The spandrels of the arches are car-
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AQUEDUCT, CROTON.
63
ried up solid to the line tangental to the extrados. From here bance-walls are carried up alternating
with openings, the latter being covered over with stone slabs, at a height of 8 inches over the extrados
here the whole is levelled off by a rubble-masonry of stone 6 inches thick. Upon this level a course of
concrete 9 inches thick is bedded, on which the aqueduct with its iron lining is erected; on the outsides
of the side-walls of aqueduct, spaces of 6 inches in width are left, in order to separate the masonry
of the aqueduct from the attic-walls, and to carry the water, draining through the earth-filling, over
the extrados and the spandrel-backing. The spaces of aqueduct between the various streets, and be-
yond them to the extremities of the valley, are supported by a dry stone-wall; stone of large size, to
the thickness of 2 feet, were laid upon their broadest beds over the whole course, the interstices filled
in with smaller ones, and all levelled off with smaller and smaller broken stone to the height of 2 feet,
on which the following course was laid in the same manner; on a width of one foot back from the out-
side, this masonry was laid in hydraulic-mortar, and the joints pointed. This part of the aqueduct has
a very substantial appearance.
THE AQUEDUCT LINE CONTINUED.-Over a distance of seven-eighths of a mile, upon which a curve of 90
degrees is turned to the left, in three various radii, the aqueduct of masonry discharges into the receiving
reservoir; upon that curve the ground has a depression of about 40 feet, and the over-filling of the
aqueduct is supported by protection-walls. Here then is the termination of the aqueduct as far as it is
constructed of masonry; and only some appurtenances still remain to be mentioned.
In order to keep the air which is confined in the closed aqueduct, in communication with the atmos-
phere, ventilators, Fig. 90, are erected at distances of every mile; buttresses a a, Fig. 91, are carried
up on each side of the aqueduct, between which the roofing-arch is carried round 12 inches thick instead
of 8 inches. In the centre of the arch thus fortified, a circular opening is left bordered with bricks or
stone upon this border the chimney-like ventilator, Fig. 90, is erected, secured at the top by a lattice.
The third of those ventilators is always of larger dimensions and provided with a door to pass into the
interior, Figs. 89 and 88, in order to facilitate examination and repair of the inner parts of the aque-
duct in cases required. The one shown by Fig. 90 is put up before crossing Clendenning valley. The
greater number of them are made of white marble, the rest of gneiss. There are of the latter kind 11
in all, and 22 of the former.
At suitable points of the aqueduct line waste-weirs are put in to draw out the water when required.
There are six on the whole line, with exception of that in the gate-house before Harlem river bridge.
A gateway, Figs. 82, 83, 84, and 85, is formed according to the marked dimensions; the waste-water
passes ough a pair of gates, bb, falls into the well c c, and discharges over d into the sewer ce. The
gates with the gateway are constructed entirely as shown in Fig. 97. and already described. When the
water rises higher than 5 feet 9 inches, measured from the deepest point of the intrados of the inverted
arch, it runs over the lip of the breast-wall and falls likewise into the well c. By means of timber
or planks i i, put against the post h, and slipping in the rabbits g g, provision is made to keep the water
in the aqueduct higher at pleasure, consequently over the mentioned 5 feet 9 inches. In the platform
at k, an opening, provided with a trap-door, is left, through which the planks ii can be put in and
taken out. Above all, a stone house has been erected. From without, the platform can be reached
by the door and over a small stair. At m, Figs. 84 and 85, a rabbit is cut in the side-walls of the
aqueduct, into which timber may be slid in order to shut off the same. Those waste-weirs at their
places serve likewise for ventilators; the one just described is put at 142d street: those on the continent
are of the same description, with unimportant differences adapted to locality.
THE RECEIVING-RESERVOIR, is built between 7th and 6th avenues, and 86th and 79th streets its
area is 87.05 acres, including the top of the embankment, or 31 acres of surface of water. By means
of an embankment it is divided into two divisions; the north one has a depth of 24 feet, measured
down from the top of the embankment, and is filled with 20 feet of water; the southern division is 29 feet
deer below the top of the embankment, 25 feet of which is water. Those depths, however, are not
throughout the same; the rock-bottom near the southern embankment lies lower than this-near the
northern embankment, higher. The contents of water amount to 150000000 gallons. Each division can
be used as a single reservoir for itself, while the other may be emptied for inspection and repair.
At the influx of the aqueduct at 85th street, west side of the reservoir, the street-level is equal with
the top of the embankment. All the other parts of embankment had to be carried up more or less in
order to reach the top, the ground being lower; and at efflux of the reservoir in 80th street, east side of
the reservoir, it is 38 feet below the top.
All the embankments are of earth, the interior puddled with clayish earth or loam. The sides on the
streets and avenues are protected by dry walls of stone, their outside being laid in lime-mortar and the
joints pointed, Figs. 127 and 128. The inside slopes of the embankments washed by water, are protected
by a dry stone pavement of 15 inches thick. At the bottom of the reservoir the bare rock or earth is
left without any artificial contrivance.
In order to keep the surface of both the divisions at a level, a connecting or communicating-pipe, Fig.
125, has been placed, of which Fig. 123 is the section; the pipe is bedded upon rock, surrounded and
supported by concrete: halfway a stop-cock is put for shutting and opening the pipe; over this cock a
circular well is erected, and carried up to the top of the embankment. Upon the top of the well
two caps are placed, on which a nut is screwed, like that at Fig. 94, by means of which, in con-
nection with the screw-bar, the stop-cock can be drawn and shut.
When the water has reached its height in the reservoir-viz. 4 feet below the top of embankment-
and the rising still continues, the surplus water falls by itself into the waste-weir well. Through the
same way 3 feet more water can be drawn off from the surface when required. by taking out the tim-
bene Over the top of this waste-weir well, a bridge with a brick arch is erected, for the passage on
the top of the division-embankment
The influent-gate, Figs. 120 and 121, receives the water from the aqueduct a, by the gate-chamber b,
and lets it either directly by the gateways e e e over the sluice-channel cc into the northern division, or by
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AQUEDUCT, CROTON.
the gateways fff through that part d d of the aqueduct which is built in the body of the western embank-
ment leading into the southern division. The various apertures of the gateways of the two entrances are
separated from each other by means of jambs of cut-stone 9 inches thick, covered over at the front,
in the gate-chamber, with stone lintels, Figs. 116 and 119, at gg ; in the rear at h h, however, the passages
are arched over with half a brick, Fig. 119. The gates, with their frames, are made as shown at Fig. 97 ;
the gate-caps rest partly in the walls and partly upon the posts 11. In order to prevent their rising, in
screwing the gates, consols n n are projected, to which the gate-caps are secured by the bolts n m. By
those two sets of gates, the water-influx to the divisions of the reservoir can be regulated completely.
Over the whole a stone building arched with brick has been erected, and covered with flags.of grey
wacke.
116.
118.
117. Top bank
Top bank
Tonwater
3
d
d
d
d
119.
TR
Top bank.
Top water.
slore of
Bottom
Southern
Division
Centerline
Bottom of Northern Division
3to.2.
Division -Binbankment
Radius
120.
Sluice
c
and
Sluice-
Channel
Northern
Division
Leading
121.
to
122.
Gate
F
a
Chamber.
Division
d
b
b
Main
a
SCALE.-1 inch 40 feet.
The efflux from the reservoir is arranged in such a manner, that the water may be drawn either from
the one division or from the other, or from both at once, each division having its own separate outlet.
Three pipes, coming out of the northern division, run in the body of the eastern embankment, protected
by a vault built in the same. At the southern extremity of the vault, upon the axis of 80th street, the
pipes are united to 3 others, leading from the southern division, making 4 after the junction. Nos. 1, 2,
and 3, carry the water to the distributing reservoir for the lower part of the city; No. 4 is for the sup-
ply of the east side of the upper town.
The arrangement of efflux is thus. a a a, 'Figs. 123, 124, 126, 127, and 131, is a tower, erected with sub-
stantial stone walls: in the open side, fronting the reservoir, is put the gate-fruming with the screen bb;
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AQUEDUCT, CROTON.
55
V
a
WASTE-WEIR
f
Coll
as
f
80
8
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of Northern Division
123
of Southern Division
124.
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Top Water
130.
Ton bank
128.
6th 6th Avenue
6th Avenue
N:27
SCALE.-1 inch - 40 feet.
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AQUEDUCT, CROTON.
the same consists of two frames, of 1.2-inch white pine timber the outer is filled with 1-inch oak slate
6 inches wide, put 1 inch apart, Fig. 131; the upper part is covered with plank; the inner, or 2d frame, is
left open as far as the just-mentioned planking reaches. Below this the gate-apertures are left-4 of such
are in the tower, Figs. 123 and 127 ; at the tower, Fig. 124, they are of 2-inch pine plank, connected by
pieces of plank nailed across and slid in wooden grooves; some of them are opened by sliding down,
some by sliding up. Opening and shutting is effected by iron rods reaching up to the gate-caps c cc, Fige.
126, 127, and 131. On the top of each rod a screw is cut, which goes into the nut put upon the gate-
caps; the nut and screw are shown by Fig. 93, at d e and i. Above this gate and screen-frame the tower
is carried higher up and roofed over. Fig. 131 is the elevation of the tower-pavilion; Fig. 127, its section,
and longitudinal section of bridge connecting the tower with the embankment. In the interior of the
tower, Fig. 127, some timbers are put for support of the gate and screen-framing when the gates are
Division Wall
Iop Water
Western Division
Eastern Division
Slope
112
state
4907
132.
133.
76'
Bottom drain
Bottom drain
m
Bottam Western Dir.
Bottom ofEastern Div.
c
C
Ion
of
Divi
Wall
20'
2
Platform
42. Street.
SCALE.-1 inch 40 feet.
elosed. At the figure named, f shows the wing-walls of the tower, and g a breast-wall, being carried
up against the bottom of the reservoir. Although Fig. 127 here is the section of Fig. 124, just as Fig.
131 is the elevation of Fig. 123, yet the arrangement and construction of the two are alike, except in
some dimensions, which at Figs. 123 and 131 are smaller.
In the rear-wall of the tower are the mouths of the pipes; the latter for some distance are bedded in
and covered over with concrete, Figs. 123, 124, and 130. When the pipes Nos. 2, 3, and 4, coming from
the northern division, have passed the line of the waste-weir sewer, D E, Fig. 123, they enter into the
pipe-vault, Fig. 129 and Fig. 128; here they join with the pipes Nos. 1, 2, and 4, and so pass on. The
letters hh show the stop-cocks; at i is a passage with stairs starting down from the avenue. In order
to prevent all sudden opening and shutting of the stop-cocks or aliding-valves, consequently the pushing
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AQUEDUCT, CROTON.
57
of the water, and to obtain a water-tight sit, a set of conical wheels and the crank, Fig. 98, were put in
connection with the stop-cock.
There are for the supply of the upper town, at the west side of the reservoir, two other effluent-gates,
of similar description and equal heights with the corresponding ones in the same reservoir-division; yet
they have their outlet through one pipe only. They are, together with the towers, of smaller dimensions
in length and width.
THE AQUEDUCT-LINE CONTINUED.-Prom the mouth of the pipes at the 6th A venue, the aqueduct, consist-
ing here of three pipes, 36 inches each, 4 feet under ground, runs along 80th street, bends round the corner
into 5th Avenue, proceeds here a distance of 2.176 miles across three depressions of ground and two
134.
Pip
e
ault
d
a
d
d
a
d
n
n
135.
t,
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Pipe area
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2
3
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b
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SCALE.-1 inch 40 feet.
heights. On the summit of the latter air-cocks are put, to allow the air to escape. At the lowest points
of the depressions there are outlets, in order to get rid of the sand which might collect here.
THE DISTRIBUTING RESERVOIR is also divided into two divisions, an eastern and a western, by means
of a division-wall. Each has a separate inlét and outlet, and may be used as a reservoir for itself, while
the other division is emptied. It is erected on the top of Murray hill, the greatest part being above
ground; as for instance-the corner marked by x, is 49 feet above the street; y, however, only 39 feet.
The outer walls a a of the reservoir, of 4 feet thickness, the inner of 6, connected together with the
cross-walls cc,4 feet thick, form the chief mass of the enclosure of the basin. The cellules dd, between
the cross-walls, are arched over 12 inches thick with bricks; their spandrels, of some feet in height,
8
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AQUEDUCT, CROTON.
backed with stone masonry then filled over and levelled off with concrete to a height of 6 inches above
the highest point of the extrados of those brick arches. The division-wall is of concrete, faced with
rough stone-masonry, Fig. 146. The bottom of the basin is puddled with earth, over which a course of
concrete, 12 inches thick, is laid; the sides are puddled, and slope up 1 foot in 4, horizontally, for 16
feet in width; then 1 to 1 to the coping of the enclosure. The lower part of this slope is covered with a
course of concrete, 12 inches thick; the steeper upper part is protected by a pavement 15 inches thick,
laid in hydraulic mortar. The slopes of the division-wall have the same protection. The upper-filling
of the cellule-arches is likewise of puddle, except 2 feet next the slope-pavement, and 2 feet below the
flagging of the platform, Figs. 134, 137, 138, 144, 150, and 151, which will prevent the frost from
penetrating into the puddle in parts not covered with water.
136.
Centerpilaster in 24 stre
Draining
25'
Draining pipe
Drain.
Influent pipes
Drain
142.
Sewer
137.
Section of Influent gate way
Ton of Division wall
Top
Drain
141.
M
Sewer
140.
139.
138.
Upper
Waste-weirwell.
Conectingnine well
Connecting-p & Waste weir
Ton-water
Sewer
8
SCALE.-1 Inch = 40 feet.
The total length of the entire structure, measured at the top of the cornice, (not in its projection,) is
420 feet; 80 the width. The basin is 386 feet square, 42 feet deep, and when filled with water 38 feet,
contains 21000000 gallons. In order to collect and drain off any water which might filter down
through the embankment i, and through the walls bb, there are left in the cross walls cc, small open-
ings nn, Figs. 134, 135, 143, 144, 150, 151, by which the water may drain from cellule to cellule with-
out the structure. Out of the northern side, the drain-water runs through the two sewers ff, Figs. 134,
135, 136, 141, 142, through the receiving-sewer gg, to the street-sewer hh. The southern part of the
structure makes its drainage in an opposite direction-viz. through the drain-sewer i to the well k,
Figs. 134, 135, from which it is carried off by the street-sewer of 40th street. Fig. 140 shows the lon-
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AQUEDUCT, CROTON.
59
gitudinal section of the sewer q, the cross-section of the well k, with the mouth of the street-sewer 4
the construction of which is given by Fig. 139; the sewer ii has a like construction as Fig. 142.
In order to draw off entirely the water from the bottom of each division, when required for cleansing
or repairing them, 2 little wells are put in, m in, Figs. 133, 137, and a slight descent of the bottom towards
them, from off all sides, arranged. In those wells the last of the contents collect, and is drawn away by
pipes marked o o in the above-mentioned figures. The pipes discharge the water into the receiving-
sewer gg; by the stop-cocks pp, those pipes can be opened and closed.
In order to keep the water of both divisions on a level, a 36-inch connecting-pipe is put through the
division-wall. Fig. 135 shows the ground-plan of the well in dotted lines. Fig. 133 is the top of the
well, with a square opening formed by jutting over the coping-stone. Fig. 139 is the longitudinal section
of pipe, stop-cock, and well.
For letting out from the reservoirs the superfluous water, a waste-weir well, in 2 descents, or for 2
cascades, has been constructed in the body of the division-wall. That water which falls from the open-
ing of the bridge 88, Figs. 132, 137, 138, 140, covering the first well, fills the water-bag below, which is 8
feet deep; it passes through the opening s, makes then the second fall down the well 8, fills its water-
bag, and is carried off through the sewer 8 h into the street-sewer of 42d street. The construction of the
sewer h is shown by Fig. 141; it has here, as well as in g, a bottom and arch of stone.
The pipes 1, 2, and 2, 3, having made their curves running parallel with each other, they end in the
pipe-areas tt, and the aqueduct itself terminates herewith. The just-mentioned figures show the course
of the pipes: Figs. 136 and 140 the cross-section of the course at the entrance into the structure of the
reservoir; and Fig. 134 the parts near the stop-cocks. Fig. 137 is their longitudinal section and sec-
tion of the pipe-area: the same figure shows also the bedding and wrapping of concrete round the
pipes in the embankment; it exhibits also the cut-off wall &
For the effluence of the water into the distributing-pipes, an effluent-tower v, with gate-frame to, is
erected for each division. Figs. 143, 145, show the ground-plan; Fig. 146, the elevation; Fig. 150, the
side-view; and Fig. 151, the section. The gate-frame has a screen at the outside, in the rear of which is
the gate-frame itself; both are supported by a breast-wall, over which the water falls upon the interior
bottom of the tower, which is 8 feet below the top of that wall In the rear wall of the tower is put
the entrance into the city-main. Each of the towers has a pipe x and 2, which are connected in the
pipe-vault by the cross-pipe x runs to the eastern part of the town, z to the central part, and tz to
the west part, for distribution. The ground-plan shows the way in which all 3 pipes can be supplied
by the one set of gates, or the other, or by both together. The arrangement for the outflow of water
answers, therefore, completely, the purpose-to empty the one division, entirely, while the other re-
mains filled.
At the lowest points of the pipes x, y, and z, draining-pipes with stop-cocks are put in, to let out into
the sewer-pit k k any sand that may collect here. The way to work the gates from the caps, as well as
the upper structure of both the towers, is shown by Figs. 145, 146, 150, and 151.
The platform of the reservoir is guarded by an iron railing. At the elevation of 119 feet above the
level of the sea, it commands a complete view of the west and east of Manhattan Island, as well as of
the south part of the city, with New York bay, and at a greater distance in that direction, the Atlantic
ocean. This view is exceedingly beautiful, and is one of the finest in the world.
DISTRIBUTION OF THE WATER.-From this reservoir, the distribution of the water is made. The above-
mentioned three 36-inch pipes convey it to the lower town, which is built closer and closer the fur-
ther down one goes; 134 miles of pipes of all sizes, between 36 and 4 inches, conduct it through the
streets, and feed several public and private fountains; these pipes are laid down in the centre of the
streets, or as near so as possible. The branchings and crossings are made by means of single or double
sleeves cast together with a main-piece. The pipes are put together with faucet and spigot, B inches
deep; at the smaller pipes, 4 inches. The pieces have a length of 9 feet, each piece making thus 9 feet run
of water-conduit when put together. Before laying down, they were proved with the hydraulic press,
with the pressure of 200 to 250 pounds to the square inch.
At the corners of streets where crossings and branchings occur, stop-cocks are put in, in order to cut
off districts of pipes, when this is required for alteration or repair. Those pipes that run off from the
street pipes, leading into the houses, are 1 to 1 inch wide, made of lead, connected to the main-pipes by
boring. Such a house-pipe has either a mouth-cock under the outdoor steps, or leads to the kitchen,
which in this country is in the basement. To feed bathing-tubs or bathing apparatus, a pipe some-
times rises to the upper-story bedrooms.
Pipes branching off for the hydrants, placed at convenient distances, are for the most part of cast-iron,
branching off from the mains by sleeves; at the larger-sized pipes, by means of boring. The hydrants, as
far as they are above ground, are protected by a cast-iron case to keep off frost, heat, and damage. For
the extinguishing of fires, the engine-hose is screwed to the muzzle of the hydrants. At the harbor,
pipes are branched out, terminating at the bulwarks, in order to supply the ships, and fill the water-
casks on board by a hose.
The cost of this aqueduct amounts to 8575000 dollars, including purchase of land required, extinguish-
ing of water-rights, and some unfinished works. This amount is within 5 per cent of that estimated by
the chief engineer, Mr. John B. Jervis, and the percentage occurs chiefly below the estimate. To this
is added 1800000 dollars, the cost for the distributing-pipes.
The first two millions had to be raised at an interest of 7 per cent, and are payable from 1847 to 1857.
For the rest, 5 per cent is paid, and to be redeemed from 1858 to 1880. 647157 dollars was the discount
for issuing the loan, which, together with the interest paid already during the construction of the work,
brings the total expense to 12500000 dollars.
The annual interest for this capital amounts to 665000 dollars, which is collected by a direct water-
tax, and some indirect taxes; by means of an existing sinking fund, the capital will be redeemed by
degrees. The water-tax amounts to 10 dollars for a house of middle size manufacturers, hotels, bathing-
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61
establishments, distilleries, livery-stables, bakeries, sugar-refineries, breweries, slaughter-houses, etc, and
ships, pay according to extension and size.
ARBOR VITE See WOODS, varieties of.
ARCHES; stone ; brick; backing of ; centering; Pierpont; screw. See RAILWAY ENGINEERING.
ARCHIMEDEAN, Boiler-furnace, and Self-acting Stern-Propeller.-Fig. 152 represents part of the
stern of a vessel fitted with this improved propeller; Fig. 153, a front view of the instrument detached
from its place in the vessel; and Fig. 154, a sectional plan of the propeller and its connections on the
line a b of Fig. 152.
152.
153.
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154.
A' A" are the blades of the propeller, which are inserted at their inner or narrow ends into sockets,
B' B", in the end of the propeller-shaft S, in which sockets they are free to turn to the extent to be
presently defined. To the shank of each propeller-blade there are two toothed segments, C'C', C" C",
attached one at top of each socket, and the other at the bottom of it; and the two sets of segments
work the one into the other within the limits determined by the stops ff, 80 that the propeller-blades
must always move in perfect unison, and can only turn round in their sockets to the extent allowed by
the stops. E is a sliding clutch, affixed to the driving-shaft inside of the propeller-blades, which may
be moved sternwards, 60 as to lay hold of either of two sets of pins, d d and e e, which project from the
back of the wheels of the innermost propeller-blade A". F is a vertical rod, by means of which the
dutch E may be worked from the deck of the vessel; this rod terminating at bottom in a screw, which
takes into a swivelled nut which is attached to one arm of a bell-crank, G, the other arm of which is
forked so as to embrace the clutch E, when brought down upon it. The mode in which the propeller,
as thus fitted, acts, is as follows :-Supposing the clutch to be disengaged, and the driving-shaft to be
put in motion, the blades are immediately thrown out into the angular positions proper for propelling,
and they will continue in these positions as long as the shaft continues to rotate. Should occasion arise
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62
ARCHIMEDEAN STERN-PROPELLER.
for backing the vessel, the blades are then secured in their extended positions by interlocking the clutch
with the pins dd. at the back of the wheels of the innermost blade, A", as represented in Fig. 154.
When the engine is stopped, and the driving-shaft ceases to rotate, and the clutch is withdrawn, the
propeller-blades will, by the action of the water upon them, be turned round in their sockets until they
come into a line with the course of the vessel, and present their sharp edges only to the water, as
156.
W
157.
exemplified in Fig. 155; and, for greater security, they may be made fast in this position by interlocking
the clutd h E, with the pins ee, at the back of the wheels of the innermost blade.
From the manner which this peculiarly fixed screw-propeller can be turned to account, from its never
being required to be raised out of the water, and never offering, when in the water and at rest, any
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ARTESIAN WELL OF GRENELLE.
63
material obstruction to the steering of the vessel, it seems to possess so far a great superiority over
all the screw-propellers hitherto in use; but it promises to be more especially advantageous in
the case of vessels going long voyages, with small store of fuel, and employing steam as an auxiliary
power only, when the wind is not fair for the use of sails. With a propeller of this description,
not a minute need be lost, in charging from sailing to steaming, or from steaming to sailing, and conse-
quently, not a pound more of fuel need be expended than is absolutely required.
The peculiar feature of this furnace consists in the employment of rotating tubular screw-bars, and
hence the name (" Archimedean") by which we have ventured to distinguish it. Fig. 156 is a longitu-
dinal section of the furnace; and Fig. 157 a front view.
H H, are the fire-bars, which, instead of being as usual, solid fixtures, consist of a series of tubes,
which are free to revolve in their bearings, are open from end to end, screw-threaded on the outside,
and perforated with air-holes. On the front end of each bar there is a broad flange or shoulder, f,
which projects beyond the general line of the furnace, and has a worm-wheel, W, formed upon it. An
endless screw-shaft, K, which passes across the front of the furnace, and is worked from the engine
through the medium of the bevel-wheels N 0, takes into the whole series of worm-wheels W, and
causes thereby the constant rotation of the fire-bars. L is a throttle-valve hopper by which the coals
are supplied to the furnace. As the coals drop from the hopper they fall upon an inclined shoot, M,
which projects them upon the front end of the furnace-bars, whence they are carried gradually forward
to the back, by the rotation of the bars and the action of their screwed surfaces on the mass of fuel.
In consequence of the bars being in this constant state of rotation, it is almost impossible that either
clinkers or ashes should accumulate upon them.
ARENE See RAILWAY ENGINEERING.
ARTESIAN WELLS. These have long existed in Italy, in Austria, in the Crimea, Siberia, Sahara,
Palmyra, Balbec, Tyre, and Egypt; their modern name arises from their having been immemorially
used in Artois, one of the departments in France. Belidor mentions one in 1749 at the monastery of
St. André, near to Aire; and in the ancient convent of the Chartreux, at Lillier, in the same neighbor-
hood, is another, more than 700 years made.
ARTESIAN WELL OF GRENELLE, Boring Apparatus of. About the year 1824, M. Péligot,
one of the superintendents of the hospitals at Paris, suggested the idea of sinking a well upon the Arte-
sian principle, and workmen were sent from Artois for the purpose; whilst this was being effected, M.
Mulot, a smith, became interested in the operation, and turned his attention to the subject; he was
consequently employed by the Marchioness de Groslier to sink one at Epinay; success attended his
efforts, and he was nominated to attempt one at Grenelle. The primitive soils, according to M. Arago,
are but rarely stratified, or are found in regular beds. The fissures in granitic rocks, the crevices sepa-
rating the contiguous masses, have but little width or depth, and do not frequently communicate with
each other in such soils the waters of filtration have but limited outlets, each film or thread termina-
ting its course alone, without receiving any increase from others in their descent. The springs being
numerous in the neighborhood, it was not thought probable that any vast quantity of water could be
obtained, as the whole of the rain penetrating the earth was supposed to pass off through various open-
ings in the sides of the hills.
The secondary soils, which are composed of a variety of rocks, in general take the form of immense
reservoirs or basins, the centre being considerably depressed, or the extreme boundaries of it greatly
elevated. Within this basin, hills, and often mountains, arise, apparently destroying its original charac-
ter. The stratification of the secondary formation is in regular beds, some of which are of enormous
thickness, composed of sand or grit, and very permeable; these permeable beds, as they rise towards
the extremities of the basin, become bare on the sides of the mountains and hills. The rain-water
which falls on the earth, after penetrating it, forms one continued sheet, which pursues its course with
great rapidity when the beds have a great declivity, and, reaching the lowest point, is accumulated in
vast quantities. One chalky or calcareous stratum, which is furrowed out in all directions, and par-
ticularly in the upper portion, allows the pluvial water to pass with great facility, and also to circulate
through the mass to a great depth: and in this peculiar stratum the wells both of Grenelle and Rouen
have been bored.
The tertiary soils are stratified, and composed of many beds placed over each other, and separated
by clean and well-defined joints, like the secondary, on which they rest; these basins are of less extent,
and derive their form from the rectifying of the beds, the elements of which they are constituted being
the same as those found on the neighboring hills. The several beds are arranged in a regular manner,
and their separation is formed by a layer of sand, through which the water freely percolates; in these
several sandy fissures it acquires force as it descends, and at great depths, its pressure being augmented,
the flow is rendered constant.
These soils are undoubtedly the best for sinking Artesian wells, because they have at their base
courses of sand lying on impermeable clays, and are less subject to dislocation or rupture than rocks of
the old formation. Such strata are easily examined, and are usually found rising from the centre of
the basin, and following an inverse direction to that of the inclination of the water, which, like a sub-
terranean river, pursues a downward course till it meets with an outlet. They frequently become bro-
ken, when the water they contain weeps into small rivulets and is carried away on the surface.
Where the well has been bored at Grenelle, the upper stratum or tertiary deposite is 41 metres in
thickness; the next is composed of chalk mixed with flint, 99 metres; then a gray chalk, without any
silex, 25 metres; to this succeeded a gray chalk, in which were iron pyrites, 341 metres; then a wealden
clay, gray sand, and a sandy clay, in which were found ammonites and other fossils; the whole depth
hored through being 548 metres, or about 1798 feet.
Before giving the description of the apparatus used in boring this well, we will give a short sketch
of the difficulties encountered and overcome by M. Mulot, to whom the direction of this great work had
been intrusted.
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ARTESIAN WELL OF GRENELLE.
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M. Mulot commenced boring in 1833 he easily pierced the tertiary sands, which are at Grenelle 180
feet thick, but shortly after having reached the chalk, at the depth of 377 feet, the sides gave way and
filled the bored space, which was cleared again, after fifty-seven days' labor; this happened in June.
1834. In May, 1837, the borer had reached 1246 feet, when the valved-spoon, together with a rod 262
feet long, fell to the bottom of the hole and were shattered to fragments; the weight of the mass was
100 cwt. Many contrivances were proposed-some even put in execution-but in vain, till M. Mulot
had the idea of wearing the ends of the fragments, and thus extracted them, fifteen months after the
accident.
In April, 1840, the instruments were wearing out rapidly, while they were making little headway
through the hard chalk, when, being raised to a considerable height, the boring-screw fell, and was
buried in the compact rock to the depth of 75 feet. It became necessary to bore all round it in order
to free it, and after many months of labor this new obstacle was surmounted.
In December, 1840, the spoon detached itself from the rod, causing a little delay in the operations of
M. Mulot, who bored a hole in the sides of the well and pushed the separated instrument into it. This
was the last impediment to overcome, and the 26th of February, 1841, the rod suddenly sunk several
feet; immediately a column of warm water 1797 feet high, equal to the pressure of 53 atmospheres,
rose from the bosom of the earth, and poured upon its surface 800,000 gallons of water, having a tem-
perature of 79 Fahrenheit.
But, besides boring, it was necessary to give support to the sides of the well, which would fall in,
unless composed of material more consistent than earth. A tube of a certain calibre is first introduced,
then another smaller one slipped within the first, and so on; but should the boring be deeper than ex-
pected, it would become necessary to withdraw these tubes in order to replace them by larger ones,
because the last must be of sufficient calibre to allow the rod to work. At Grenelle it was necessary
to draw off five series of tubes, and to bore larger holes to introduce tubes of a greater diameter.
The following is a table of the strata bored through.
Nature of the Strata.
Thickness.
Depth beneath
the soil.
Feet.
Feet.
1
Foundation of a basin
7.21
on the surface
2
Alluvial soil, composed of rolled flints and gravel
24.40
7.216
3
Chalk
2.78
31.652
4
Plastic clay, lignites, iron pyrites, and sand, penetrated by sul-
phuret of iron
65.69
84.44
5
Marl and calcareous sand, containing nodules of compact lime-
stone
36.11
100.13
6
Chalk and silex in lumps
312.89
136.25
7
Hard gray chalk with silex
652.92
449.14
8
Gray chalk, very hard, alternating with more soft chalk
423.18
1104.23
9
Green chalk
.98
1524.20
10
Blue chalk with clay
101.73
1526.0
11
Black and blue clay, with strata of green sand, containing iron py-
rites and fossils
101.79
1658.51
12
Argillaceous sand
2.30
1780.28
13
Green sand
4.50
1792.57
Water
1797.47
Description-The apparatus consists of a crane with four beams A, iron-bound. At the summit
there are four pulleys of cast-iron B, on these the chains C pass; these chains also go through two
other moveable pulleys DD'. The chains C, attached by one end to the guide-strap of the pulleys
DD', are hooked by the other extremity on the conical drum E E', around which they are wound in
opposite directions. By these pulleys the iron bars F, 26.24 feet long, to which are attached the bur-
rowing instruments, are lowered and raised.
To raise the rods, eight horses are harnessed at G, Figs. 158 and 159, which being set in motion, one of
the chains passing through the pulley H coils round E, while the other chain is unrolled. The pulley D, to
which the rod F is suspended by means of a hook, is raised, and brings up all the boring apparatus.
When this pulley has reached the top of the crane the second pulley D' is made fast; then the bar just
raised is taken off by men standing on a; the hook is fixed to the next bar, and the horses are driven in
the opposite direction. While the pulleys are exchanged, the top bar is seized by the crank J,
placed at the orifice of the well to prevent it from falling. The cranks J are formed of two strong iron
plates, between which are set two eccentric chaps J1 J2, which allow the rods to ascend, but prevent
their falling back.
One man is necessary to lower the rod, which is accomplished by pulling or loosening the break,
Figa. 158 and 159, at pleasure. This double break consists of two large hoops K K', surrounding the
drum L, which is covered with a thick sheet of iron; one of the extremities of the hoops is fastened to
the horizontal beam M, while the other is kept in place by a square placed out of the works, and opened
or closed by a lever.
The next thing to be considered is how the rod is turned. It is adapted to the wheel N,
which is made to communicate with the wheel, Fig. 163. The toothed-wheel N, is for this purpose
changed from the position it occupied, Fig. 158, to that represented Fig. 162, corresponding to the
axis of the well; a square hole is made in the centre to receive a square bar of iron .2624 of a foot
9
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ARTESIAN WELL OF GRENELLE.
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square and 18 feet long, which is adapted by one extremity to the boring-rod, and by the other is sus-
pended to the hook of the pulley D. When the wheel N is fixed to the rod it is adapted to its inter-
mediate toothed-wheel P, fixed to a wooden frame close by the crane. The wheel P is put in connec-
tion with the great wheel Q placed over the wheel R, to which two, and sometimes three horses are
harnessed. The burrowing-rod is suspended by chains run into a ring g, Fig. 159, and coils round the
drum S, Figs. 158 and 163', situated on the other side. The wheel T serves to raise or lower the
instrument.
When the wheel R is put in motion, the rod receives the movement of rotation imparted to N by the
toothed-wheel P. The men at T allow the rod to descend slowly. The pulley D' would be in the way
during the operation, it is therefore fixed by a pin to the links of the chain.
Explanations of the Figures.-Fig. 158.-A vertical and longitudinal section of the apparatus in a
plane passing through the axis of the well, and of the wheel used to lower and raise the borer.
Fig. 159.-A horizontal section of the wheel G, made above the breaks; the two conical drums,
around which the chains are wound, being omitted.
Fig. 160.-A horizontal projection of the drum L, and of the breaks.
Fig. 161.-A front view of the two frames U U', placed in the horizontal beam, near the wheel G
Within these frames two smaller frames are made to slide; they have wooden rollers, и and u', and are
intended to support and guide the chains C, to the drums E'. These chains, when slack, rest on
the rollers w'. The frames U and U' have their superior part in contact with the beams V and V',
which are fastened by one extremity to the crane, and by the other to the strong bearer, X. The pillow
of the axis of the wheel G, rests also on this bearer.
A flooring, Z, connects the wheel to the crane, and places within the reach of the workmen the parts
just described.
Fig. 162.-Vertical and transverse section of the apparatus, whose plane is perpendicular to that of
the section, Fig. 158.
Fig. 163'.-A view of the drum used for supporting and lowering slowly the borer as it sinks.
Fig. 164.-Plan of the wheel R, Fig. 162.
Fig. 165.-A profile view of the frame and wheel N.
Fig. 166.-A plan of this frame, which slides in grooves made in the beams O, Figs. 158 and 162,
on small friction-rollers. The small flooring n, gives passage towards the centre of the wheel N, in
order to adapt the rod in it.
Fig. 167.-Front view of the wooden support to the toothed-wheel P, Fig. 162.
Fig. 168.-A horizontal section of this support, and plan of the wheel.
Figs. 169 and 170.-A front and profile view of one of the moveab.e pulleys, D D', with its guide-
strap, giving attachment to the hook d, to which is suspended the borer by a ring.
Figs. 171 and 172.-An external view of the crank J, with a section following the line 1-2.
While the boring goes on, this is set over the orifice of the hole; to this end, two semicircular pieces
j are attached to the plates J, and rest on the ground. The rods pass between J and the nippers
J1, Jª. As long as the rods are raised the nippers yield; but as soon as they remain motionless, either
to change the rods or for any other motive, the arcs through their eccentricity press against the bars
and prevent their descent. To secure them further, their other sides are held by the force-screws jª.
Fig. 173.-A fragment of galvanized iron tube, 0.016 of a foot thick, used as a conductor to the water.
Figs. 174 and 175.-Pincers used for the extraction of fragments of wood or other matters.
Fig. 176.-Section of the foregoing, following the line 3-4.
Figs. 177 and 178.-Pincers for withdrawing the tubes.
Fig. 179.-A horizontal section of a branch in the direction of 5-6.
Figs. 180 and 181.-Details of an instrument called Caracol, used to withdraw fragments of the rod
when they have penetrated into the parietes of the well.
Fig. 182-A plan of the instrument.
Figs, 183 and 184.-Screwed rods composing the borer. The superior bar has a hook also vised to it.
Figs. 185 and 186.-Rods united by means of pins, the heads of which are buried in the thickness of
the bars. The end of one is fissured, in order to receive the end of another rod.
Figs. 187 and 188.-A ring which is attached to the rods by three pins.
Figs. 189 and 190.-A chisel, called Trepan, used to perforate the hard rocks which it is necessary
to break and to crush at the same time. There are three edges, a, b, c. The edge a is double, b and c
are turned in opposite directions. This implement will cut the rock and crush it in whatever direction
it is turned.
Figs. 191 and 192-A valved spoon, used in sands and clays almost rendered liquid by the water in
which they are in suspension. It consists of a long cylinder in sheet-iron, open at both extremities, the
inferior being strengthened by an iron ring with a sharp edge. A little above this ring there is a disk,
at the centre of which a round hole has been perforated. This opening is perfectly closed by an iron
ball. When the spoon is lowered into the hole the sand pushes away the ball, which, however, falls
back by its weight, closes the orifice b, and allows the extraction of the sand. The ball is prevented
from rising too high by the perforated disk c.
Figa 193 and 194.-A vertical section and external view of the borer, used to enlarge the hole. It is
very solid, and consists of a hollow cylinder, whose inferior extremity is furnished on its circumference
with fluted knives, of which there are several of different dimensions.
Fig. 195.-A view of the underneath part of the preceding.
Fig. 196-Shows the mode of attachment of a knife to the ring, and also a front view of the knife.
The knives are firmly attached to the inner ring, and are surrounded by another ring of greater diame-
ter. The whole is traversed by a pin.
ASH. See WOODS, varieties of.
ASPHALTE. See RAILWAY ENGINEERING.
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AUGERS.
69
ASPEN. See WOODS, varieties of.
AUGER, Ship Carpenter's. This is a very ingenious
197.
instrument, invented by Richard Coffin, of Haverhill,
Mass, and the following explanation will convey an idea
ased
of its uses.
c
A is the foot. D is the frame. C is a rod and crank
F
F
attached to the auger H. B is the cup and head. E is
the spring. G G are two rods for the purpose of discon-
E
D
necting the catches FF from the rod C.
If you wish to bore, pull the spring E by the handle to
the left; shove down the left-hand rod G, to disconne t
the left-hand catch from the rod C. The right-hand catch
holds the spring. and throws its power towards the auger
H, and so on; the cup B allows its ball to roll in the frame
and auger in any position, and the thumb-screw will hold
it in that position; the other thumb-screw is to hold the
slide which elevates or depresses the auger.
AUGERS. See BORING TOOLS and RAILWAY ENGINEER-
ING.
AUGER, improved. This is the invention of Mr. Wil-
A
liam Ash. Its object is to produce holes of various diam-
eters by one instrument by having the cutting and gui-
ding parts detached, 80 as to change them at pleasure.
204.
203.
Figs. 198, 199, 200, and 201, represent the auger in
three different positions. Fig. 201 shows its end. A is the
spindle; B the conical screw; C the worm fitted on the
K
spindle. The upper end of the worm is made to bear
against the stop D. F is the cutter fitted into a mortise
in the spindle, fastened by the wedge-piece G. The cut-
ter F, is shown above in four detached positions, Fig. 202.
202.
K
The lower end of the worm bears against the back of the
cutter, and the wedge G rests also in a small notch cut in
201.
the face of the worm, as seen in Fig. 200. On taking out
the wedge the cutter can be taken out, and also the worm,
when another worm or cutter of a different size may be at-
tached to the spindle. In this way the cutter can be taken
out and sharpened at pleasure. Instead of the worm C,
the guides, Figs. 203 and 204, are sometimes substituted.
Fig. 203 is a vertical, and Fig. 204 a horizontal, section.
198.
This guide consists of a ring, KK, having a slightly conical
209.
199.
screw-thread on the outside, from which extend two
wings, II, supporting a thimble, L Through this thimble
the spindle A passes, and the cutter being applied to bore
the wood, the opening of the hole is only to be cut in the
first place, then the ring of the guide is firmly screwed
c
into that orifice; and in boring, the cutter will then be
directed by the spindle sliding through the thimble. By
the worm the chips are carried up out of the hole. By
the guide the chips will rise through the opening K and
the thimble L The worm appears to be, by far, the best
guide.
AUGERS, machinery for making. The object of the
inventor, Mr. Palmer, is to manufacture the single-twist"
e
auger, usually made of a rod of metal, twisted round a
cylinder into a helical curve. The auger which the inven-
tor's machinery is intended to manufacture, is formed
of a long rod of metal, (either of a triangular or other prop-
er shape, in its cross-section.) The iron should be rolled
c
in square bars or rods, of the size required, and be cut
into pieces of sufficient length, to make the tool or instru-
c
ment intended. A small piece of steel of proper size for
the cutting-lip, and the conical screw, if it is to be added,
is next welded upon one end of each one of the pieces,
and the end is next turned or bent down at right angles to
the remainder, upon an anvil, so as to fit into the cavity of
the lower section of the dies, for forming the lip, or the lip and screw cone. About three-fourths of the
length of the rod from the steel knob is next heated to the necessary temperature, to be rolled down by
the next portion of the machinery. The next portion of the process of manufacturing the auger, consists
in forming the cutting-lip, or the cutting-lip and conical screw-blank, upon its end. For this purpose,
dies are employed to form the lip without the conic blank. The head of steel being heated, is placed
between the dies, and the upper of them caused to descend, with the force necessary to swedge or
compress the metal into the shape required. The knob thus formed, is next bent down to the angle re-
quired, to be applied to the machine, by which the rod is twisted in the helical curve. The next operation is,
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70
AUGERS.
to give the requisite degree of uniformity to the size and spread of the twist,
905.
906.
207.
which is accomplished by hammering in the machine, consisting of a trip-
hammer, arranged and operated over a die-anvil or bed-piece, grooved
out, 80 as to receive the twisted helix when laid thereon. By turn-
ing the auger around, first in one direction and next in the opposite, succes-
sively, so as to cause it to pass back and forth between the hammer and
bed-piece or anvil, the twist is spread out in a uniform manner. The lower
part of the hammer should be curved to correspond with the circumference
of the exterior of the twist of the auger. The twisted portion of the auger
is again heated, and rolled between heavy iron plates, for the purpose of
straightening the twist; during which operation, care should be taken that
the cutting of the auger does not come in contact with the plates. The
auger is next to be finished by filing, and upon grinding and polishing
wheels, or by other proper means, in such manner as may be desirable
and when a screw is to be connected with the cutting-lip, it may be cut
upon the blank by any contrivance adapted to the purpose.
AUGERS, double and single twist. Improvement in single and double
twist augers, by Sandford, Newton, and Smith, of Meriden, Conn. :-
This improvement consists in what we term a graduated twist, and is
effected by 80 constructing the auger as to produce a uniformly decreasing
length of twist, with a corresponding gradual tapering of the cavity of
the auger, from the shank to the lower or cutting extremity. Any person
skilled in the art of making augers can form the graduated double-twist
with tongs and hammers, in the ordinary mode of twisting double-twist
augers, by exercising due care and attention. A better method is to have
the dies in what auger manufacturers call crimp-jaws, 80 constructed as
to conform in size, graduated length of twist, and taper of the cavity, to
the proposed auger. The auger having been first twisted by the common
method, with the tongs and other tools, to about the shortness of a
medium in the proposed twist, is, while hot, put into the crimps, which
are then brought suddenly together by the usual process, the auger being
at the same time turned partially round, backward and forward. The
twist is thus made of a gradual increasing length, with a corresponding
gradual enlarging cavity from the lower or cutting end to the other
extremity of the twist, as is represented in Fig. 205 in the drawing an-
nexed.
To form single-twist augers with this improvement, see Fig. 206, that
part of the rod which is to form the twist, should, before being twisted,
be drawn with a graduated taper from the part which is to form the
shank, to that which is to form the lower or cutting end. The auger may
then be twisted in the usual way, by having the mould upon which it is
formed or twisted, made to conform in size, graduated length of twist.
and taper of cavity, to the proposed auger. The mould is a machine
well known to all makers of single-twist augers.
The superiority of augers made with this improvement consists in, that
the clogging of the chips or core in the twist, while in the process of
boring, is effectually prevented; thereby materially diminishing the fric-
tion. And also, that the shortness of the twist at the lower end gives
a better opportunity to finish the cutting-lips, 80 that they may bore
more smoothly and evenly than when the auger is made in the ordinary
way, with a slack or open twist.
What the inventors claim as their improvement and invention, are the
making or constructing double or single twist augers, with a gradually
increasing length of twist, and the consequent gradual enlargement of
cavity from the lower or cutting end to the other extremity of the twist.
AUGER, double-lipped, convex, and concave. Improvement in the form
and construction of concave screw-augers, by N. C. Sandford, Meriden,
Conn.-This improvement consists as follows: Instead of having the
plate, from which the auger is to be twisted, of concave shape throughout,
as is usual in forming concave augers, the lower extremity of the plate
is of convex shape, or of even thickness, though the former is preferred.
In augers of five-eighths diameter it will be sufficient to have about one
inch of the lower extremity of convex shape, or of even thickness, as
aforesaid, varying in proportion as the diameter of the auger is increased
or diminished.
The advantage of this mode of construction consists in, that the work-
man, when twisting the auger, which is done in the ordinary mode, is
better enabled to give to the plate a short twist at the lower extremity,
and finish the cutting-lips or edges in the best and most approved
method for easy boring, than when the plate is formed in the usual way,
of concave shape throughout.
What Mr. Sandford claims as his invention, is the forming of the lower
part of the plate of a convex shape, or of even thickness, when this is
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AUGER MACHINE
71
combined with the upper part of the plate formed of a concave shape. The whole plate being formed
for the purpose of making therefrom a double-lipped, convex, and concave auger.
AUGER MACHINE This new and useful improvement in the mode of equalizing and straightening
the twist of double and single twist screw augers, invented by Sandford and Smith, of Meriden, Conn.,
may be described as follows:
Set firmly in the ground, or otherwise secure to the floor, two posts, marked a, Fig. 208, about six
sr : apart and fifteen inches in diameter, of sufficient length to elevate the machine to a convenient
208,
209.
a
a
distance from the ground. Upon the upper surface of these posts is placed horizontally, and se-
cured strongly, a piece of timber b, say of oak, about twenty inches wide on its upper surface, and four
inches thick. This we term the bed of the machine. Two straight cast-iron bars c, about two inches
thick and two inches wide, of the same length as the bed, and raised about twelve inches therefrom, and
then placed about twelve inches apart, parallel to each other and to the bed. Each of these bars is
secured to the bed by two vertical posts of iron, D. Fig. 208 shows the machine as thus far construct-
ed. We then take a piece of cast-iron, say two feet long, fourteen inches wide, and one inch thick, with
its edges raised about one inch, 80 as to form a dovetail on its upper surface. This we call the
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72
AUGER MACHINE.
lower stock, and is represented by that portion of Fig. 210 marked h. This stock is placed in the
centre of the bed, between the bars; screws passing through the bed and attached to the stock,
serve to elevate or depress it at pleasure. Another screw, passing through the centre of the stock
and through the bed, enables the operator to confine and hold the stock firmly on the first-named four
screws.
Another piece of cast-iron, of similar dimensions, but with the dovetail on its under surface, is then
placed under the bars, 80 that about one inch of each edge of the upper surface of its entire length
shall bear upon the under surface of the bars. This we term the upper stock, and is held to the
bars by four hooks, marked g, in Fig. 209, attached to the upper surface of the stock, and resting in the
upper surface of the bars, so as to admit a sliding movement of this upper stock. This movement is
effected by means of a rack e, and pinion; the rack, to be of sufficient strength, should be formed of
a cast-iron bar, about two inches square, and of the same length as the bars, with cogs about two inch-
es in length, and is attached lengthwise to the surface of the upper stock. The pinions and shaft
should be of corresponding dimensions; and being turned by means of a crank or wrench, give an
alternate backward or forward movement to the upper stock. Fig. 209 represents the machine with
the upper stock k, and the lower stock h, in their respective places, and the rack e, and pinion at-
tached. There are then inserted into these stocks, metallic plates, or dies, of about one inch thickness,
which fit into and are securely held by the dovetails above mentioned. To each of these plates, or
dies, are secured, by means of rivets or screws, two wales of cast-steel, running parallel to each other
in an angular direction across the plates. Fig. 210 shows one of these plates i, partially inserted in the
stock h. When the plates are separated from their respective stocks, the wales upon the plate are designed
for the lower stock, and vice versa; 80 that when the plates are inserted in their respective stocks,
the wales upon the upper plate run in an opposite direction from those upon the lower plate, form-
ing an angle with each other. The size of the wales will depend upon the size of the auger to be
formed and the angle at which they cross the plate must be governed by the openness or closeness
of the proposed twist, so that separate plates, adapted to each size of auger respectively, will be re-
quired.
If it is desired to form the auger so as to make the graduated twist, it may be effected by slightly
curving and also tapering, as shown in Fig. 212, the wales; increasing or diminishing the curve and
taper, in proportion to the degree of graduation contemplated.
210.
211.
212.
2
The plates are adjusted at the proper distance from each other, required by the size of the auger to
be formed, by means of the screws.
To work the machine the crank is turned backward, 80 as to move the upper plate directly over
the opposite extremity of the wales upon the lower plate, as shown in Fig. 211. The machine is then
ready for operation. The auger being twisted by hand in the usual way, (which can be done with
great expedition, as particular nicety in this respect is rendered unnecessary by the use of the ma-
chine,) is placed while hot in the machine, with the part nearest the shank on the wales, which being
adapted to the size of the auger to be operated upon, will fill the cavity of the twist. The upper
plate is then moved forward by turning the crank, and rolls the twist part of the auger between the
plates, these giving it an exact and uniform size; while, at the same time, the wales operate upon
the cavities of the twist, opening or closing them as may be necessary, and by a single forward move
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AUTOMATIC DIVIDING MACHINE.
78
ment of the machine, produces a perfectly even and regular twist. Thus forming a better article, and
at less expense, than can be done by any method now in use.
Messrs. Sandford and Smith, claim the raising upon and securing to the surface of level metal-
lic, or other plates composed of hard substance, wales running either in straight or curved lines, and
operated substantially in the manner just specified, for the purpose of forming the twist of double and
single twist screw augers.
AUTOMATIC DIVIDING MACHINE, arranged for use in the Coast Survey Office, by JOSEPH Sax-
TON, assistant in the office of weights and measures, Washington, and constructed by William Würdeman,
mechanician, coast-survey office-The dividing machine, which has been rendered automatic by Mr. Sax-
ton, was imported for use in the coast-survey office, by the late F. R. Hassler, Esq., superintendent. The
graduations made by means of it, by different persons, were unsatisfactory. Many causes were assigna-
ble for this, and it was considered by the present superintendent, Professor A. D. Bache, desirable that
the most obvious of the causes of
error should be got rid of, by render-
ing the machine automatic, before the
minor causes of irregularity were
sought for. This was done by Mr.
Saxton, in the manner described in
213.
the following pages. The result has
B
B
been very successful, not only in its
M
first application, but in permitting
W
the determination and removal of
sources of error, previously conceal-
ed in the working of the machine.
The drawings of the proposed ad-
ditions upon a scale necessary for
working, were made by Mr. Saxton,
and the work was executed by Mr.
William Urdeman and his assist-
H
ant mechanicians in the coast-survey
office. Accuracy, beauty of finish,
ease of reading, economy of time,
and labor in dividing, have all been
T
gained by the improvements.
The machinery for rendering the
dividing machine automatic, consists
of a brass wheel A, about 20 inches in
diameter, mounted on the axis B, Fig.
213. One of the arms of the wheel A
has a slit extending from near the cen-
tre of the rim ; in this slit is fixed the
crank-pin so that it can be placed at any re-
quired distance from the centre. On the edge
of the wheel is turned a groove, in which runs
a cord for driving the wheel. On the other
214.
end of the axis is fixed the wheel C, which is
geared into the wheel D, on the lower end of
the vertical shaft E, Fig. 214. On the upper
end of the same shaft, is another wheel F,
El
geared into the wheel G, on the horizontal
shaft H. On the end of the shaft H, is a wheel
I, which gears into the wheel J, on the axis K.
The wheels CDFGI and J are all bevel
wheels, having the same number of teeth, (60,)
and work into each other at right angles.
H
The shaft E has on it a sliding-joint L, for
215.
altering its length; the shaft H is turned and
ground of uniform thickness, 80 that it may
a
slide accurately through the socket of the
a
O
wheel G, and also through its bearing at M, in
which it turns. The axis K has on it two ec-
centrics, N and 0: N to raise the tracing point,
and o to move it horizontally. One-half of the
U
circumference of N is concentric with the axis
b
on which it turns, so as to keep the point up
R
e
while the crank-wheel moves half a revolution,
and is moving the dividing plate. The other
is eccentric to the axis about one-tenth of
an inch, 80 as to let the point rest on the circle
while it is making the division. The eccentric
0 has about fth of its circumference concentric to the axis; the rest is described from a point about fth of
an inch from the centre. N and 0 must be fixed on the axis with regard to each other, so that N will raise
the point before o begins to move it back, and both with regard to the crank-wheel A, 80 that the point
10
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74
AUXILIARY EXPANSION.
will be raised before the crank begins to move the dividing plate, and keep it up until it is done moving,
and o has moved the point back, and then let it down before 0 begins to let it return. The axis K has
also on it, near the end, a small cog P, to shift the ratchet-wheel Q one tooth every revolution of K. The
ratchet-wheel has 60 teeth, and is kept in its proper position by the detent spring R. In front of the
wheel, and fastened to it by two screws, is a circular plate S, Figs. 213 and 215, with 20 notches in its
edge, the deepest one for the longest line, or 5°; the next for 30'; and the shallowest for 15'; and the
edge of the plate for the 5' lines.
The segment T, Figs. 213 and 215, is fixed on the vertical part of the tracing-frame U, and has a pin
in the end at V, of such a size that it can drop into the notches in S, as they are brought under it by the
revolutions of the ratchet-wheel, and 80 regulate the length of the division lines. The time of raising the
ratchet must be when the stop-pin is raised out of the notch, by the motion of the traces backwards.
To give motion to the screw, a stout fusee-chain is used, one-eighth of an inch broad, and one-fourteenth
of an inch thick, which answers well; one end is attached to the ratchet-barrel W, round which it is
wound five or six turns; the other end is attached to the crank-pin X. Near the lower end of the chain,
at Y, is a small tube, containing a strong spiral spring, arranged like the common spring weighing-ma-
chine, but having a motion of only about fth of an inch; the spring must be 80 strong as not to give by
the force required to turn the screw, but only to give a little when the ratchet comes up to the stop, and
the crank is just passing the lower centre. Between the spring and the crank-pin is an a. rangement for
lengthening or shortening the chain, when it is arranged for making a larger or smaller division; for this
purpose, two pieces of brass wire, about six inches long, having a screw cut on them their whole length,
and each filed away one-half, and two small milled nuts, tapped with the same thread, are run on each
the two wires are laid together, and the nuts screwed up until they embrace both wires, as shown at Z,
Fig. 213.
The crank-pin is fixed on a slide, projecting beyond the nut which fastens it, 80 that it may be extended,
if necessary, beyond the circumference of the wheel, or by reversing, it may be brought quite to the
centre. When the divisions are to have the long end towards the centre, a jointed lever, as shown at a,
Fig. 215, is used. It is screwed fast to the cross-bar b, Figs. 214 and 215, directly over the eccentric o,
and connected to the vertical frame U at c, and the stop-pin V is shifted to the other end of T, and the
abutting piece f on U, is to be removed, when the eccentric 0 will act against the lever a, at d, and
move the point in an opposite direction. The tracing-frame is made to follow the eccentric, by a weight
and cord passing over a pulley and hooked to the vertical part of the tracing frame at ee, Fig. 215.
When the adjustment is made for dividing with the long end of the division lines, towards the circum-
ference of the circle, all the wheels connecting the axis K with the axis B should be marked with a dot
on the tooth and space in which it works, and a line should be drawn on the shafts E and H, and a cor-
responding mark on the sockets through which they pass, 80 that they may always be fastened in the
same position. The axis K should have two short pins fastened on it, and notches in the ends of the
sockets N and O, to fix them in their proper position when the lines are towards the circumference or
centre, as the case may require. The slit in the crank-wheel A, in which the crank-pin is fastened, should
also be graduated, showing the distance of the pin from the centre, for each degree, minute, and second
that may be required in dividing.
By marking the position of each part of the machine in this way, much time and trouble will be saved
in making the necessary changes for different kinds of dividing, whether it be in the number, or the di-
rection in which the long lines are to be extended. The tracing point should be adjusted so as not to
be raised more than about the thirtieth of an inch, or it will be liable, in descending, to make a small dot
at the commencement of each line, which would injure the appearance. In the drawing, the eccentric
N is represented as acting on the tail of the tracing-frame, but it is better to make it act on a steel pin
in the side of the tail.
By this arrangement of the crank for turning the dividing-screw, the stops of the ratchet are brought
in contact when the crank is passing its centres, and the motion of the screw is so slow, that it is not pos-
sible for the stops to strike so hard as to do any injury, and the dividing may be done with great ra-
pidity.
AUXILIARY EXPANSION. Slide-frame and Gearing.-See LOCOMOTIVE ENGINE and TENDER.
AWLS, various kinds of. See BORING TOOLS.
AXLES, GREASE FOR RAILWAY. Booth's Grease for Railway Axles.-Water 1 gallon, clean tallow
8 lbs., palm oil 6 lbs, common soda f lb.; or tallow 8 lbs., and palm oil 10 lbs. The mixture to be
heated to about 210° F., and well stirred till it cools down to about 70°, when it is ready for use.
AXLE GREASE; for Railway Carriages. Some mystery has been made on this subject, and
patents taken out for various articles, but I believe, from experience, the following is the t:-Take
56 or 60 lbs. of soda; dissolve in about 8 gallons of water in a small boiler; when quite dissolved, to be
poured into a large tub or wooden cooler, containing from 80 to 36 gallons of cold water, and well
mixed. Tallow to be melted (according to the proportions hereinafter stated) in a 60-gallon boiler.
After being thoroughly dissolved, palm oil is to be added, and then the mixture allowed to boil; as
socn as it boils the fire to be taken out of the furnace, and the mixture to be cooled gradually, and to
be frequently stirred while cooling. When cooled down to blood-heat (98°), it is to be run off through
a sieve into the cooler containing the water and soda, and it must be stirred during the whole of the
time it is running off, in order that it may be properly mixed.
Proportions of Oil and Tallow.
Summer Weather.
Winter Weather.
In open Weather, (Spring or Autumn.)
Palm oil
1 cwt. 1 qr.
I
Palm oil
1 cwt. 3 qrs.
"
I
Palm oil
1 cwt. 2 qrs.
Tallow
1
"
3
Tallow
1
"
1
"
Tallow
1
"
2
44
}
equal quantities.
AXLES, for turning Narrow Curves. This is an improvement in the construction of Railroad Car.
Axles, invented by Messrs. Morse and Mansfield, Machinists, Canton, Mass.
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AXLES.
75
This invention has been effectually tried during the past year on the Boston and Worcester, the
Boston and Providence, and several other Railroads in New England, and the valuable practical
testimony of the Superintendents and Engineers of these roads is highly favorable-exceedingly 80.
The saving of tear and wear of the wheels where it has been used, has far exceeded expectation. The
nature of the invention consists in having each axle as it were divided and hung in two middle suspen
sion-bearings, which are allowed to swing on pivots, whereby the angles of the wheels can be diverged
from the straight line for the better turning of narrow curves, than by extended immoveable axles.
216.
A
B
6
B
B
A
217.
F
E
C
C
K
X
D
D
W
DESCRIPTION.-Fig. 216 is a view looking down upon the truck, and Fig. 217 an end elevation. The
same letters refer to like parts on both figures, therefore we will describe the engraving collectively.
A A A A are the wheels. BBBB are the axles. CC are pinion and rack coupling. DD, Fig.
217, are the pivot axis of WW, the suspended axle-bearings. K K K, are the transverse timbers of the
truck-frame. E is a pinion-crank, and F F are vertical bolts in the end of the pinion-crank to fit into
recesses in the bottom beams of the car. G is an iron socket to receive a vertical bolt fixed on the
bottom of the car. H H are friction pulleys to case the friction of the car upon the middle of the truck.
The bolts FF, and the bolt in the car to fit into socket G, secure the car. to the truck. E, we call a
pinion-crank, from the fact that below its cap-plate it has notches that fit into notches on the upper end
of the swing axle-bearings. These notches coincide about one quarter of the circle on each side of the
pinion with the notches in the upper part of W W, therefore the top of W W moves in slots in CC, as
will be observed in Fig. 216. The operation of these axles is obvious; they prevent torsion, also much
wear of the wheels and rails too. To allow the wheels to change with the angle of the axle as seen in
Fig. 216, the outside journals of the axles are fixed in their boxes in such a manner that both the
shoulders and journals move in their boxes and work very nicely.
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AXLES.
It will here be observed, in the outeet, that the car acts as a guiding lever to make the axles and
wheels conform to the curvature of the road.
Fig. 218 is a top view, and represents the position of the wheels, axles, and body of the car passing
over a double curvature. LL are the rails, and KK the body of the car. Fig. 221 is an enlarged
view of two wheels and axles, and the axle-boxes with part of the car-frame. A A are the wheels.
BB are the axles. ZZ are the central pivots of the car-body. Each wheel has a single axle for itself;
and it has this advantage over other cars, that if one axle breaks, or one wheel, there is no danger of
the car breaking down-the car will run steady upon three wheels to a truck. The inner ends of the
axles are hung in suspension oscillating boxes, having cogs on the upper parts. Fig. 219 represents an
oscillating box. D is an inside shoulder, and C are the cogs on the upper part. These boxes are at-
218.
221.
K
oz
E
c
F
K
K:
219.
220.
00
oz
tached by pivots to the central longitudinal beam of the car, and are retained in square plates, firmly
secured to the central beam. E is a plate, on the under side of which are teeth to mesh into C, the
open part of the axle bearing like pinion and rack coupling, and F is a crank with a bolt or wrist on
the end of it, to fit into a slot in the bottom of the car-body KK. To allow the wheels to change with
the angle of the axle, as seen in Fig. 219, the outside journals of the axles are fixed in their boxes in
such a manner that both the shoulders and journals move in their boxes and work very nicely, as
represented in Fig. 220. B is the axle. H, the axle-block; which, from the dimensions of the box,
allows the axle at the outer end to move in unison with the other end of the axle in its oscillating
bearings. The two crank-plates on each truck, which have wrists projecting into recesses of the bottom
of the bar, are of unequal lengths, as seen in Fig. 218, 80 that the front and hind wheels will describe
different angles, the whole conforming to the curvature of the road. A mathematical problem is in-
volved in the combined motion of the car-body and wheels, which cannot be rendered plain in this de-
scription, but its operation in Fig. 218 is correctly represented.
The ingenious inventors are Messrs. Jedediah Morse and William Mansfield, both practical men; the
former of Sharon, and the latter of Canton, Norfolk Co., Massachusetts.
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AXLES.
77
AXLES, Vibrating Box for Locomotives-Invented by Norris & Tull, of Philadelphia. The arrange-
ment of this box allows it to revolve in a vertical plane, at the same time that it floats up and down,
the journals of the drivers having, at all times, their full bearing upon the box. Let the axle assume
any position from a horizontal line, caused by inequalities of the road, or the consequent raising of the
outer rail in passing curves, which must necessarily reduce friction in a great degree, and insure the
more perfect working of the engine, without producing any undue strain in its several parts; it has
2211
d
(4)
223.
222.
m
A
m.
m
B
225.
224.
n
n
IF
SC
B
b
b
m
m
a
c
only to overcome the friction which is due to the surfaces upon which it works. This evil. has always
been overlooked in the construction of locomotives, and which must occur when a box floats vertically
in a pedestal.
Fig. 221}.-Elevation of pedestal with vibrating-box.
Fig. 222.-Cross-section of the same.
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78
AXLE AND WHEEL.
Fig. 223.-Ground plan.
Fig. 224.-Vibrating-box.
Fig. 225.-Bearing of vibrating-box.
A A, pedestal forming part of the wrought-iron frame. B, vibrating-box resting with the two pivots
b', which are firmly attached to it in openings of the two sliding-pieces c'. Fig. 225 shows an end
view of one of the latter, with its flanges m m', and the hole a, which is to receive the pivot b. These
sliding-pieces are connected, by means of screws x x, with the cross-piece d, the lower surface of which
is cylindrical, and forms a bearing for the upper convex surface n n', of the box B. f, wedge, kept by
the set-screw f' in a position which allows the box to slide in the pedestal without being too loose or
too firm. g, oil-box. In Fig. 224 this oil-box is omitted.
The same parts are marked by the same letters in the different views.
AXLE AND WHEEL, or the wheel and axle, is a kind of lever, in which a plane is moveable about
an axis perpendicular to that plane, or 80 contrived as to have a continued motion about its fulcrum, or
centre of motion, where the power acts at the circumference of the wheel, whose radius may be reckoned
one arm of the lever, the length of the other arm being the radius of the axle, on which the weight acts.
If the power acts at the end of a handspike fixed in the rim of the wheel, then this increases the lever-
age of the power, by the length of the handspike.
22b.
The wheel and axle consist of a wheel having a cylindrical axis passing through
its centre. The power is applied to the circumference of the wheel, and the
weight to the circumference of the axle.
In the wheel and axle, an equilibrium takes place when the power multiplied
B
C
by the radius of the wheel, is equal to the weight multiplied by the radius of the
axle; or P: W : CB.
For the wheel and axle being nothing else but a lever so contrived as to have
a continued motion about its fulcrum C, the arms of which may be represented
W
by A C and BC; therefore, by the property of the lever, P W CA
P
If the power does not act at right angles to C B, but obliquely, draw CD per-
P
pendicular to the direction of the power; then, by the property of the lever,
P: W CD.
It will be easily seen, that if two wheels fastened together and turning round
the same centre, be so adjusted, that while they turn round they will coil on their circumferences strings,
to which weights are suspended; one of those wheels being larger than the other, the larger wheel will
coil up a greater length of the string than the smaller one will do in the same time, and this will de-
pend either on the radii or circumferences of the two wheels. The velocity of the weight will be in
proportion to the length of string coiled in a given time; therefore, the velocity of the weight will be
greater as the wheel is larger. Now, as in the lever, we saw that a small weight required a greater
velocity to balance a large weight with a small velocity, we may infer, that the rules given for levers
will also apply to the wheel and axle; since the velocity of any body on a lever depends upon its dis-
tance from the fulcrum.
EXAMPLE-A weight of 13lbs. is to be raised at a velocity of 14 feet per second, by a power whose
velocity is 20 feet per second; how great must that power be 1
13 X 14 ÷ = 9.1, the power required.
If the velocity of the weight, be to that of the power, as 14 to 20, and the radius of the axle on which
the weight is coiled be 7; then, 20 X 7 ÷ 14 = 10, radius of wheel on which the power acts.
If a weight of 36lbs. is to be raised by an axle 3 inches diameter; what must be the power applied
at the end of a handspike 4 inches long, fixed in the rim of the wheel connected with the axle, the wheel
being 6 inches diameter
Here the handspike will increase the distance of the power from the fulcrum, and will add to the
diameter of the wheel twice its own length; therefore, 8 + = 14 ;-hence, 14 : 3 36 : 7.77, the
power required to keep the weight in equilibrio.
Wheels acting on each other by teeth or bands, may be easily calculated in the same way. Thus,
if a wheel which has 30 teeth, drives another of 10 teeth, it is evident, that as the larger wheel has
three times as many teeth as the smaller, the smaller wheel will be turned round three times for once
that the larger one is turned round so that the velocities of the wheels will be inversely as their num-
ber of teeth. In like manner, it is clear, that if the larger wheel drives the smaller not by teeth but by
a band, their revolutions will be inversely as their circumferences.
EXAMPLE-The number of teeth in one wheel are 160, and in another driven by it are 20, and the
larger wheel makes 12 revolutions in a minute; how many does the smaller one make 1
20 : 160 : : 12 : 96 = the number of turns which the smaller wheel makes in a minute.
The larger wheel is usually called the wheel, driver, or leader, and the smaller one is called the
pinion, driven wheel, or follower.
Let us now see what would be the action of two wheels and a pinion, if the first wheel contains &
teeth, the pinion 12 teeth, and second wheel 36 teeth. Place the first wheel and the pinion on the same
axis, 80 that they move together, one revolution of the one being in the same time as a revolution of the
other, and the pinion drives the second wheel. If the first wheel makes 16 revolutions in a minute, the
pinion will do the same, and the pinion drives the second wheel; therefore, 36 12 16 : 5f = the
velocity of the second wheel. Place these so, that the teeth of the first wheel act in the teeth of the
pinion, and these again act in the teeth of the second wheel. If the first wheel make, as before, 16
turns in a minute, then the pinion will make 12 80 : 16 : = in a minute; consequently, the
revolutions of the second wheel will be 36 : 12 35.55 = turns the second wheel in a minute.
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AXLE AND WHEEL.
79
When there are a number of wheels ABCD,
227.
acting on the respective pinions a bcd, then the
c
D
effect of the whole may be found thus: if the let-
ters which represent the wheels and pinions be
understood to signify the number of teeth of each,
power X AX BX CX D
aXbXcXd
weight.
If the velocity of the first wheel be used instead
of the power applied, then this rule will give the
resulting velocity instead of the weight.
EXAMPLE-If the numbers of the teeth of the
wheels are 9, 6, 9, 10, 12, and those of the pinions
6, 6, 6, 6; then if the power applied be 14lba,
we have
14X9X 6 X 9 X10X12
6x6X6X6X6 = 105lbe, the weight. And, by the remark under the rule, if the first
make 14 revolutions in the minute, the speed of the last will be 105 in the same time.
The same rule will apply to the case where the wheels act on each other by ropes or straps, if the
circumferences of the wheels and pinions are used for the number of teeth.
It often happens, in the construction of machinery, that two shafts must be connected by means of
toothed wheels, in such a way, that the velocity of one shaft shall bear a certain proportion to that of
the other shaft; and we must determine the number of teeth in each of the connecting wheels and
pinions.
Take the respective numbers of teeth in the pinions at pleasure, and multiply all these together, and
their product again by the number of turns that the one shaft is to make for one turn of the other shaft.
Take, now, this product, and find all the numbers which will divide it without a remainder, or divide
its divisors without a remainder-always excepting the number 1. Arrange all these in one line, and
separate them into parcels or bands, each containing as many numbers, or factors (as they are called)
as you please; but observing, that there must be as many bands as there are wheels required; then
the product of the numbers in each band will give the number of teeth in the respective wheels. Thus,
if one shaft is to turn 720 times for another shaft's once, and there be interposed 4 pinions, one of which
is fixed to the end of the one shaft, each pinion having 6 teeth or leaves: then, 6 X 6 6 720;
all the divisors or factors of which are 3, 2, 3, 2, 3, 2, 3, 2, 2, 2, 3, 5, 2, 2, 3; these divided into 4 bands
at pleasure, give the number of teeth in the wheels. Thus,
2X3X5 =80,
3X8X5
= 45,
Either
2X2X2X3=24,
Or,
'= X x
2X2X3X3=36,
{
3X3X2
=18,
2X2X3X3=36,
3X2X2X2
=24,
The application of what we laid down may be thus illustrated. In finding the number of teeth in
the wheels of an orrery, we extract from Marrat's Mechanical Philosophy. There is considerable
difficulty in proportioning the number of teeth in wheels for clocks, orreries, &c., the problem indeed is
indeterminate; we shall, however, give an example, that will point out a method by which any inge-
nious mechanic may complete a piece of machinery, such as an orrery, so as to show, at all times, in
what part of its orbit any planet is. The following example is for Mercury: this planet goes round the
sun in 87d. 23h.; now as the hour-hand of a clock goes round twice in 24 hours, it will make 17511
revolutions in 87d. 23h. For the fraction 11, take any multiple of the denominator plus or minus unity,
and make it the third term of the proportion; thus say, as 12 : 11 515 472 nearly; for 111 is one
unit less in each than a multiple of 1/2 by 473; hence the revolutions become. 175 472 00597.
Now the only difficulty remaining, is to find proper factors or divisors that will divide the numerator
and denominator without a remainder, in order to determine the number of teeth and leaves in the
wheels and pinions. For the numerator, the best method Mr. Grier found is to make trial of the num-
bers 2 X 5 or 10, as often as we can, and if we do not succeed, to try successively the prime numbers
3, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, &c. He found by trials the numerator will break into the
factors 101 X 39 X 90597, and concluded then that these numbers 101, 39, 23, may be the num-
ber of teeth in three wheels. We can easily break the denominator into the numbers 103 and 5; but
as 103 is too large for the teeth in a pinion, and being a prime number, another number must be sought
for that will answer the purpose better. Again say, as 12: 11 1825 : 1673; the revolutions now
become 1751873, or 39104. Hence we find by trial that the numerator (321048) can be broken into
the factors 91 X 72 321048, which may be three wheels having that number of teeth in each.
Again, the denominator of the fraction, or 1825, is capable of being broken into the factors 73 X 5 X 5
= 1825. Now the product of the number of teeth in all the wheels, divided by the product of the
number of teeth in all the pinions, will give the revolutions. For example, 321048- ÷ 1825 = 175 revo-
lutions, 11h. Om. 1s. 58 thirds, which does not exceed the 87d. 23h. (or 17511 revolutions) by two
seconds. The numbers last found for the wheels and pinions, may be transformed by multiplication
into more convenient numbers, as
98 73 X 10 X 5 91 72 = 144 73 10 175r. 11h. Om. 1s. 58th., either of which will be a train of wheel-
X
work proper for such я motion, and this train may be conveniently attached to the pinion of the hour-
wheel of a clock. The reason for finding a new fraction, will appear evident; for if we take the original
number, 175H we shall find it impossible to break the numerator into factors without leaving
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80
BACKING OF ARCHES.
a fraction, which is inconsistent with wheel-work, as nothing but whole numbers will answer the pur-
pose. It is obvious, that the higher we take a multiple of H the nearer we approach to the true time
of revolution, provided we can break the numerator and denominator into proper numbers for the teeth
and leaves of the wheels and pinions. It is necessary to observe, that there must be either three
wheels and three pinions, or, if the numbers when broken be too large, if we can break them into five
wheels and five pinions, it will be the same thing; because, as the hands of a clock go round with the
sun, that motion would make two wheels and two pinions (attached to the pinion on the hour wheel)
go round the contrary way to what they ought; but three or five will answer the intended purpose.
BACKING OF ARCHES. See RAILWAY ENGINEERING.
BACK LINKS. See DETAILS OF ENGINES.
BACKWATER, or SCOURING POWER. The stream of water employed in connection with harbors, to
carry away the shingle and prevent its accumulation at the mouth. They are employed where a great
quantity of water can be obtained at high tides, large reservoirs being filled at such times, and the
water is afterwards discharged on the bar at low-water.
BALANCE-GATES. A certain description of floodgate, much
228.
used in Holland, acting upon the following principle: the gates are
fixed on a vertical shaft as a centre, and are kept closed by the pres-
sure of the water against them, one side of each being larger than
the other and in order to open them, when requisite, a sluice is con-
structed in the largest side, which, upon being opened, reduces the
area of this side of the gate to less than that of the other side upon
which the water consequently acts upon the gates, and opens them.
BALKS. A term applied to long pieces of timber, from about 5
to 12 inches square.
BALANCE-VALVES. See VARIETIES OF STEAM-ENGINES.
BALLAST-WAGON. The wagon employ-
ed in removing earth in excavations, and the
229.
like, the which hold about 2 cubic yards, or
21 or 8 yards at the utmost. even by piling up.
If they are filled too full they are apt to tilt.
They are usually used without springs, but they
are better with them, particularly for those
working on permanent rails, as the former in-
creases the wear and tear of the rails, and adds
to the expense of maintaining the way. The
cut shows an improved form of ballast-wagon. See EARTHWORK.
BALLASTING, or METALLING, (sometimes called Bottoming.) A term applied to the covering of
roads generally, and to the filling-in material, above, below, and between the several stone blocks and
sleepers upon railways, dc. it is laid for the purpose of keeping the road dry, as in the event of water
lying upon it, the rails invariably sink, as it causes them to rest unequally.
Ballasting is mostly composed of gravel, broken stone, or the like, and is laid about two feet thick on
railways, the finished surface of it being usually rather more than one inch below the level of the
rails, and it is generally from 6 to 12 inches thick on roads.
A longitudinal drain, six inches square, is sometimes laid within railway ballasting, having cross
drains, 15 feet apart, communicating with the same, to convey the water into the side ditches. These
drains should invariably be used in excavations and when employed in embankments, the water is led
down the slopes by drains.
BALUSTRADE A series of balusters situated and fixed under the coping of the parapet of a
bridge, &c., which are not employed in engineering works so frequently as formerly.
BALL VALVES OF LOCOMOTIVES. See DETAILS OF ENGINES.
BANDING PLANES. See CHISELS AND PLANES.
BAR. A piece of timber or metal placed horizontally, and running across from one part of any
framework to another.
BAR, (in navigation.) An accumulation of sand or shingle at the commencement or mouths of rivers,
harbors, &c, being formed by the action of the tides.
BARBERY-WOOD. See Woods, varieties of.
LAROMETER, or VACUUM GAGE. See DIMENSIONS OF STEAM-ENGINES.
BAR-WOOD. See WOODS, varieties of.
BARREL, (of a drum-wheel.) The cylindrical body or axle round which the rope is rolled.
BARREL (of a pump.) The cylinder, or hollow part of the pump, in which the piston works.
BARROW. A machine generally used for carrying soil in the formation of excavations and other
works at their commencement, before a road is formed.
BASE LINES, (in surveying.) The main lines of a survey, upon which the correctness of the whole
depends; it is therefore necessary to proceed with the utmost care in the laying out of the several base
lines of a survey.
BAT. The name given to a half, or other portion of a brick.
BATH-STONE. A very serviceable sandstone, almost wholly calcareous, although some of it is
more silicious. It is extremely soft when taken out of the quarry, but afterwards becomes hard. In
setting the stones, it is very essential to lay them in their natural or quarry bed, which remark may be
applied to every description of stone, although not in the same degree as with Bath-stone.
BATTER. The face of a retaining, or other wall, when built in a leaning position, the top part fall-
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BEETLING MACHINE.
81
ing back within the line of base; walls of this description are sometimes termed tallue walls. The bat-
ter of a wall is either straight or curved; the latter are also generally commenced straight from the
top, the greatest degree of curvature being given to the bottom of the wall.
BAY-TREE. See WOODS, varieties of.
BEAM. Of Land Engines, to find the vibration of studs; depth at centre; the total depth is equal
to the diameter of the cylinder; depth of beam at ends; thickness of beam; studs of beam; when of
cast-iron; when of wrought-iron. See DETAILS OF ENGINES, and DIMENSIONS OF ENGINES.
BEARINGS. Management of; spherical advantages of. See MANAGEMENT OF ENGINES, and DETAILS
OF ENGINES.
BEARINGS, as applied to carriages, &c. The chairs supporting the framework of the carriage,
which merely rest on the axles and upon the outside of the wheels of railway-carriages; but they are
fixed to the axles of all common road-carriages.
BEECH. See WOODS, varieties of.
BEEF-WOOD. See Woons, varieties of.
BEETLE A wooden instrument, or mallet, for driving piles, being raised by the help of ropes and
pulleys: the term is also applied to the rammer used for driving stones into the ground.
BENCH, or BERM. A ledge left on the face of a cutting to strengthen the same. Steep cuttings
should always have ledges to support them, particularly in canal work, to prevent the mould from the
upper part falling down into the water; chalk may also be executed at a very steep inclination by their
assistance. Ledges are likewise generally made at a change of slope, occasioned by meeting with a
different soil.
BEETLING MACHINE. This invention relates to improvements in producing various kinds of or-
namental and other figured fabrics, by pressure from corrugated or indented surface-rollers, of various
patterns; and consists, first, in the peculiar construction and arrangement of suitable machinery called
beetles, in which one or more grooved or indented roller, or rollers, form the principal feature of these
improvements; the said rollers being employed for the purpose of giving to woven fabrics a glossy
finish, similar to that which is now produced by the ordinary stamps used in the machines called
beetles. Also, for improvements in arranging and applying steam or fluids to such purposes, thereby
giving a certain pressure to the rollers employed in the improved beetle; and, further, for a combina-
tion of mechanical arrangements necessary for the construction of a roller-mangle, with a sufficient
pressure to produce, when required, the operation of beetling. The accompanying engravings
represent, at Fig. 230, a front elevation, and at Fig. 231, an end elevation of the above-mentioned
machine, with the samé letters of reference applying to similar parts. A A are cast-iron stand-
ard frames, having side-claw projecting bearings BB, Fig. 231, with two central horn-shaped ones A¹,
carrying the pressure-lever links; CC are bush-bearings for the journals of the beetling-rollers D and E,
which rotate horizontally with each other in opposite directions; F F is the roller upon which the cot-
ton fabrics, about to undergo the beetling process, are wound; G G is the pressure-roller, mounted in
the lever-link motion-head H H, upon the central horn-standard in a manner subsequently explained;
I is the shaft upon which the pressure-roller revolves; K K two connecting-rods on each side of the
machine, attached in vertical positions at the top to the links HH, and at their lower ends to the
weighted levers L; M is the centre stud, upon which the levers L L radiate; N N are two spherical-
shaped balls or weights, for giving pressure to the roller G. through the medium of the levers LL, as-
sisted by their own gravity; o is the bearing on which the connecting-rods KK move; P is an inter-
mediate crank motion-rod, coupling the two way link-shafts V R, and giving motion horizontally to the
longitudinal rest-bars TT, through the quarter-way links SS, in gear with the same; U U are two
spur-wheels, mounted upon the beetling roller-shafts D and E, in gear with a pinion V, on the driving-
shaft; W X is a long hand-lever, the object of which is to raise the different- rollers from their beds by
it in the manner hereafter explained. Having thus far described the various arrangements and parts
of which this invention consists, it is necessary to explain its mode of working, and the numerous advan-
tages that may result from its application to the various purposes for which it is intended. Steam,
or other motive power, is in the usual manner first applied to the driving-shaft W, which is
mounted in a bracket bearing against the standard-framing, as represented in the engraving; whilst
the other end is similarly mounted against a wall or other convenient place, and when driven by the
action of steam, it causes the pinion V, on the end, which takes into the spur-wheels UU, to propel
the same, and thereby give the required motion to the machine or apparatus during the process of
beetling. It must be observed, that the cotton fabrics about to be mangled or beetled, are first wound
upon the roller F; to accomplish which, the roller has to be removed or taken out of its place, which
is performed in the manner hereafter explained. Having completed the operation of winding the cotton
on the rollers, it is then passed between the beetling-rollers D and E, which are furnished with periph-
eries, such as are seen in the two smaller engravings annexed; these are embossed. or checkered
in different patterns corresponding to the rollers employed. The fabries are then taken from the
rollers and replaced by others, during the working of the machine, and the operations effected.
The pressure to which the fabrics are exposed by the constant rotation of the rollers between F hich
they pass, is produced and carried into effect as follows roller G G, with its moveable link-
bearings on each side, centred on the horn-shaped standards, are caused, through the medium of the
side connecting-rods KK, to receive the entire weight of the levers LL, in addition to the weights
H H on the ends, and consequently offer a sustaining pressure to the fabrics during the process of
beetling. On the other hand, when it becomes necessary to supply the apparatus with plain cotton fab-
rics, and remove those already beetled, the levers L L. which are represented as having holes at one
end for the employment of any suitable or convenient tackle, are to be by such means raised, the action
of which will have the effect of raising also the head-links and pressure-roller, and thus, by removing
the weight, enable the roller beneath to be lifted out of its seat, and placed in one of the end claw-
bearings BB, as represented by the dotted lines. The mode of effecting this part of the operations will
11
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82
BEETLING MACHINE.
be readily comprehended by reference to the engraving, Fig. 231, where TT shows a bar of iron hori-
sontally placed on each side, beneath the journals of the roller F, forming a rail or table upon which
they are to be moved. When a downward motion of the lever handle is given by the operator, it causes
the coupling-rod P, through the medium links P R, in connection with others on the same shaft, in gear
with the rest-bar TT, to move upwards horizontally, similar to the action of a parallel rule, and raise
the rollers F or B out of, or into their respective places, by enabling the rollers to be rolled along
them, when disengaged from their bearings or seats, and carefully lowered into their places, in readi-
ness for the next operation. From these observations it will be seen that, first, the levers LL are
to be raised in the manner which will cause the roller GG to be also raised, through the medium of
230.
H
H
G
B
B
U
X
D
R
W
N
L
V
231.
A
A
H
I
J
K
X
B
B
I
T
A
s
E
A
B
M
N
L
the connecting-rods KK, when the pressure will be removed from the lower rollers, and which will
enable them to be raised to the required height, 80 as to transfer them from one seat or bearing to
another, and thus allow the fabrics to be changed by removing those already having undergone the
process, and supplying the other roller with plain ones. The patentee, although he describes and sets
forth the employment of the side-levers, yet does not confine himself exclusively, as other and equally
effectual means may be applied with the same advantages, such as steam pressure, liquids, or other
wise; and in many cases the weight of the rollers themselves might be found sufficient to give the re-
quired pressure without the intervention of additional pressure.
The next object to which the patentee directs attention, is to the improved mode of construct-
ing roller-manglea, which consists of very nearly the same arrangement of rollers, the only apparent
difference being, the introduction of a flexible lever or spring, firmly fixed to the standards upon which
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BELTING.
88
the pressure-roller is mounted, being brought to act upon
232.
the same to any degree of force, by the application of a
hand-wheel and screw-spindle, supported in bearings, suit-
ably arranged. To the end of the screw-spindle two fixed
studs are attached, between which the lower end of the
flexible lever or spring is introduced, 80 that when the
spindle is screwed to or from the centre of such stand-
ard, carrying the roller, the pressure is applied by rea-
son of the standard moving from a centre with the rol-
ler under an elastic pressure thus given by the forward
or backward application of the screw hand-wheel spindle.
The patentee states that cast-iron rollers may be employed
for dry articles, but for damp ones, bell-metal would be
found better adapted. One of the advantages derived
from this system of mangling is the small space the ma-
233.
chine occupies, together with the accommodation which it
offers by being placed within a piece of furniture having
drawers for the purpose of disposing of the various articles
when 80 mangled, and thus forming a very useful piece of
furniture, and which may, if necessary, be rendered high-
ly ornamental in place of the present incommodious ma-
chine now in use. The same principle also extends to
a portable description of mangle, which the patentee
states may be temporarily set up on a table or dresser,
and made to answer all the purposes for which it is in-
tended, motion being given to it by hand-levers in the
usual manner, but employing, as a means of giving pres-
sure, a lever, as in the first-mentioned instance; but with this difference, that the connecting-rod K,
in the beetling apparatus, has in this instance a rack and pinion as a means of adjusting it, so as
to obtain the requisite pressure. The patentee, after describing the peculiar forms given to the several
rollers comprising a series of different patterns, and the best means of constructing them and forming
the corrugations or indentations upon them, would wish it to be distinctly understood, that he claims
as new and of his invention :-First, the employment of rollers having indented, grooved, checkered, or
undulated surfaces or peripheries, for producing by pressure corresponding marks or impressions there-
with upon cotton or other fabrics. Secondly, for the general arrangement of parts constituting the
action and construction of the said improved machinery. Thirdly, for the employment of water or
other fluids within the aforesaid rollers, to act independently of other pressure apparatus, such as the
long levers in Figs. 230 and 231, of the annexed engravings; also for the application of steam to such
purposes, causing, in the usual manner by its expansion within a cylinder, a pressure to be exerted upon
the rollers, and at the same time that such application should be available for the purposes of taking
off and removing the pressure when required, the same means employed for the one shall be found
effectual in performing the other. Fourthly, and lastly, for the use of the numerous patterns as applied
to cylinders employed in the process of beetling, or to other like machines or apparatus, either for
mangling, or otherwise, as hereinbefore fully detailed. See CALENDERS.
BELL-METAL See DETAILS OF ENGINES.
BELLS. See CASTING AND FOUNDING.
BENCH MARKS, (in surveying.) Fixed points left on the line of survey for reference at any future
time. consisting of cuts in trees, pegs driven in the ground, and the like.
BETON. A French concrete or mortar, used in the foundation of hydraulic works: it consists of
twelve parts of puzzolana, nine of quicklime, six of sand, thirteen of stone scablings, none exceeding
the size of an egg, and three parts of iron scales from the smith's forge; after being well mixed and
indurated together, it is broken in pieces, and a coffer having been previously prepared, it is dropped
by & proper box into the same, and laid in alternate layers with rubble stones, until sufficiently elevated
to receive the masonry.
BELTING. We have taken this article from C. E. Leonard's valuable book, "The Mechanical
Principia."
The following table shows the velocity of belts: the column marked Revolutions Shaft," shows the
number of revolutions which the line or driven shaft is supposed to make per minute; the column
marked 44 Diameter Drum," shows the diameter of the drum on the line or driven shaft. EXAMPLE:-
The line shaft is required to make 120 turns per minute, and it is desired to have the belt run 1800
feet per minute; required, the diameter of the driven drum. Find 120 in the column marked " Revolu-
tions Shaft;" opposite to this number in the table find 1800, or the nearest to it, which is 1884 feet ; over
this number in the column marked Diameter Drum," will be found 5 feet, the diameter of the drum-
EXAMPLE-The line shaft makes 100 turns a minute, the diameter of the driven drum is 4 feet
required, the number of feet the belt moves a minute. Find 100 in the column marked Revolutions
Shaft," opposite to the number in the table, and under 4 in the column marked Diameter Drum," will
be found 1256 feet.
Digitized
by
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84
BELTING.
No. 1.
Revolu-
DIAMETER DRUM.
tions
Shaft.
2
21
3
31
4
41
5
51
B
100
628
785
942
1099
1256
1413
1570
1727
1884
110
690
863
1036
1208
1381
1554
1727
1899
2072
120
753
942
1130
1318
1507
1695
1884
2072
2260
130
816
1020
1224
1428
1632
1836
2041
2245
2449
140
879
1099
1318
1538
1758
1978
2198
2417
2637
150
942
1177
1413
1648
1884
2119
2355
2590
2826
160
1004
1256
1507
1758
2009
2260
2512
2763
3014
170
1067
1334
1601
1868
2135
2402
2669
2935
3202
180
1130
1413
1695
1978
2260
2543
2826
3108
3391
190
1193
1491
1789
2088
2386
2684
2983
3281
3579
200
1256
1570
1884
2198
2512
2826
3140
3454
3768
The following table shows the required width of belts to transmit different number of horse power.
The apparent degree of accuracy in this table is not obtained for any practical use, but to show the
theoretical power of belts; when the belts exceed 12 inches in width the fractions may be omitted.
This table is calculated upon the velocity of the belts being from 25 to 30 feet per second, which is
the ordinary velocity; if the power to be transmitted exceeds 20 horse, and circumstances will not
allow the centre of the drums to be over 15 feet apart, the power should be transmitted by gearing.
EXAMPLE-Required the width of a belt to transmit 20 horse power from a water-wheel, the diame-
ter of the smallest drum being 6 feet. Find 20 in the column marked " Horse Power opposite to this
number in the table, and under 6 in the column marked Diameter," will be found 12 inches, the width
of the belt.
EXAMPLE-Required the width of a be! in transmit 100 horse power from an engine, the diameter
of the smallest drum being 5 feet. Find 100 in the column marked Horse Power;" opposite to this
number in the table, and under 5 in the column marked 'Diameter," will be found 72 inches, which can
be divided into four 18-inch belts, or any desired width.
No. 2.
DIAMETER.
Horse
Power.
2
3
4
5
6
7
8
9
10
1
1.8
1.2
0.9
0.72
0.6
0.514
0.45
0.4
0.36
2
3.6
2.4
1.8
1.44
1.2
1.028
0.90
0.8
0.72
3
5.4
3.6
2.7
2.16
1.8
1.542
1.35
1.2
1.08
4
7.2
4.8
3.6
4.88
2.4
2.056
1.80
1.6
1.44
5
9.0
6.0
4.5
3.60
3.0
2.570
2.25
2.0
1.80
6
10.8
7.2
5.4
4.32
3.6
3.084
2.70
2.4
2.16
7
12.6
8.4
6.3
5.04
4.2
3.598
3.15
2.8
2.52
8
14.4
9.6
7.2
5.76
4.8
4.112
3.60
3.2
2.88
9
16.2
10.8
8.1
6.48
5.4
4.626
4.05
3.6
3.24
10
18.0
12.0
9.0
7.20
6.0
5.140
4.50
4.0
3.60
12
21.6
14.4
10.8
8.64
7.2
6.168
5.40
4.8
4.32
14
25.2
16.8
12.6
10.08
8.4
7.196
6.30
5.6
5.04
16
28.8
19.2
14.4
11.52
9.6
8.224
7.20
6.4
5.76
18
32 4
21.6
16.2
12.96
10.8
9.252
8.10
7.2
6.48
20
36.0
24.0
18.0
14.40
12.0
10.280
9.00
8.0
7.20
25
45.0
30.0
22.5
18.00
15.0
12.850
11.25
10.0
9.00
30
54.0
36.0
27.0
21.66
18.0
15.420
13.50
12.0
10.80
35
63.0
42.0
31.5
25.20
21.0
17.990
15.75
14.0
12.60
40
72.0
48.0
36.0
28 80
24.0
20.560
18.00
16.0
14.40
45
81.0
54.0
40.5
32.40
27.0
23.130
20.25
18.0
16.20
50
90.0
60.0
45.0
36.00
30.0
25.700
22.50
20.0
18.00
55
99.0
66.0
49.5
39 60
33.0
28.270
24.75
22.0
19.80
60
108.0
72.0
54.0
43.20
36.0
30.840
27.00
24.0
21.60
65
117.0
78.0
58.5
46.80
39.0
33.410
29.25
26.0
23.40
70
126.0
84.0
63.0
50.40
42.0
35.980
31.50
28.0
25.20
75
135.0
90.0
67.5
54.00
45.0
38.550
33.75
30.0
27.00
80
144.0
96.0
72.0
57.60
48.0
41.120
36.00
32.0
28.80
85
153.0
102.0
76.5
61.20
51.0
43.690
38.25
34.0
30.60
90
162.0
108.0
81.0
64.80
54.0
46.260
40.50
36.0
32.40
95
171.0
114.0
85.5
68.40
57.0
48.830
42.75
38.0
34.20
100
180.0
120.0
90.0
72.00
60.0
51.400
45.00
40.0
36.00
Digitized by
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BELTING.
85
It is immaterial whether the smaller drum is the driving or the driven drum; if the diameter of
the smaller drum remains constant, the width of the belt will remain constant, if the diameter of the
other drum should be increased indefinitely.
The following table shows the required width of large belts to drive different numbers and kinds of
spindles with looms-the columns marked Mules," Mules and Frames," and Frames," show the
number and kind of spindles to be driven, the column marked No. Yarn," shows the number of yarn
which the spindles are supposed to spin, the column marked Diameter," shows the diameter of the
smaller drum.
No. 3.
smallest drum being 6 feet. Find 5000 in the col-
umn marked Frame Spindles;" opposite to this
DIAMETER.
number in the table, and under 6 in the column
marked Diameter," will be found 32 inches, or
Frame
Spindles.
No. Yam.
34
5
6
7
8
two belts 16 inches wide.
1000
30 to 40
13
10
8
61
5f
49
No. 8.
2000
44
64
26
20
16
13
11
9
3000
"
"
39
30
24
19
16
14
4000
44
"
52
40
32
26
22
18
Spindles
DIAMETER.
5000
46
"
65
50
40
32
27
23
Mule
48
39
33
28
and
6000
-
"
78
60
Frame.
No. Yarn.
3
4
5
6
7
8
No. 4.
1000
20 to 30
13
10
8
6f
5f
5
2000
66
66
26
20
16
13
11
10
3000
"
"
39
29
24
20
17
15
DIAMETER.
4000
"
"
52
39
31
26
22
20
5000
"
"
65
49
39
33
28
25
Mule
6000
"
"
78
58
47
39
33
30
Spindles.
No.
Yarn.
3
4
5
6
7
8
1000
10 to 20
13
10
8
7
6
5
No. 9.
9000
"
"
27
20
16
13
11
10
3000
"
#
40
30
24
20
17
15
4000
-
66
54
40
32
27
23
20
Spindles
DIAMETER.
5009
&
"
67
50
40
34
28
25
Mule
6000
$
66
81
61
49
40
34
30
and
Frame.
No. Yarn.
3
4
5
6
7
8
No. 5.
1000
30 to 40
12
9
7
6
5
4f
2000
"
"
94
18
14
12
10
9
3000
"
"
36
27
21
18
15
13
DIAMETER.
4000
"
"
48
36
29
24
20
18
5000
"
"
60
45
36
30
25
22
Mule
6000
F
"
72
36
31
27
Spindles.
No. Yarn.
3
4
5
6
7
8
54
43
1000
20 to 30
12
91
If
6
5
41
No. 10.
9000
&
-
25
19
15
12
10
91
3000
be
to
38
28
23
19
16
14
4000
"
44
50
38
30
25
21
19
DIAMETER.
5000
F
66
63
47
38
31
26
23
6800
$4
&
76
57
45
38
32
28
Frame
Spindles.
No. Yarn.
3
4
5
6
7
8
No. 6.
1000
10 to 20
16
12
10
8
7
6
2000
"
66
32
24
19
16
14
12
DIAMETER.
3000
"
"
48
36
29
24
21
18
4000
"
"
65
48
39
32
27
24
Mule
5000
"
"
81
61
48
40
34
30
Spindles.
No. Yarn.
3
4
5
6
7
8
6000
"
"
97
73
58
49
41
36
1000
30 to 40
111
9
7
51
47
41
2989
#
"
234
17
14
11
If
81
EXAMPLE-Required the width of a belt to
3000
66
to
35
26
21
17
14
13
drive 2000 mule spindles with looms, the number
4000
4.
"
47
35
28
23
19
17
of the yarn being 28, and the diameter of the
5000
$
06
58
44
35
29
24
21
70
52
42
35
29
26
smallest drum being 3 feet. Find 2000 in the col-
6000
"
"
umn marked 'Mule Spindles;" opposite to this
number in the table, and under 3 in the column
No. 7.
marked Diameter," will be found 25 inches, or
two belts 12h inches wide.
Spindles
DIAMETER.
Mule
and
No. 11.
Frame.
No. Yarn.
3
4
5
6
7
8
1000
10 to 20
15
12
11
8
64
6
DIAMETER.
2000
"
&
30
24
21
15
13
11f
3000
66
"
45
36
32
23
20
17
Frame
4000
66
66
60
48
43
30
26
23
Spindles.
No. Yarn.
3
4
5
6
7
8
5000
"
"
75
60
54
38
33
29
6000
64
"
90
72
64
45
40
35
1000
20 to 30
14
11
81
7
6
5
2000
"
64
29
21
17
14
12
11
3000
"
"
43
32
26
21
18
16
EXAMPLE-Required the width of я belt to
4000
"
"
57
43
34
29
24
21
drive 5000 frame spindles with looms, the number
5000
"
"
72
54
43
36
31
27
6000
«
"
of the yarn being 35, and the diameter of the
86
65
58
43
37
32
Digitized by Google
86
BELTING.
The following table shows the required width
No. 16.
of counter-belts to drive the counter-shafts which
MULE SPINDLES.
drive the different machines represented in the
following table.
DIAMETER.
No. 12.
Mule.
PICKERS.
10
12
14
16
18
20
22
24
26
28
30
600
12,
101
81
71
61
6
5f
5
41
41,
4
DIAMETER.
900
18
151
121
111
91
91
81
71
62
61
6
Beaters.
1200
241
20!
17½
14)
13
124
10
101
94
81
81
1500
307
251
211
184
16
15
13
12
111
101
10.
10
12
14
16
18
20
22
24
26
28
30
EXAMPLE-Required the width of a counter-
1
6f
5f
4f
41
3)
34
3
2
13
11
9
81
71
6f
6
54
5
41
4
belt to drive a picker with two beaters, the diam-
3
18
16
13
121
11
9f
9
74
71
7
61
eter of the smallest pulley being 18 inches. Find
2 in the column marked "Beaters;" opposite to
No. 13.
this number in the table, and under 18 in the
column marked Diameter," will be found 7 inches,
30-INCH CARDS.
the width of the required belt.
DIAMETER.
No. 17.
Cards.
FRAMES, (LIVE AND DEAD) SPINDLES.
10
12
14
16
18
20
22
24
26
28
30
2
51
41
3]
31
3
21
DIAMETER.
3
78
6s
51
43
41
4
34
34
3
4
104
81
71
61
6
51
48
41
41
31
34
Frame.
5
13
10
9
8
7t
64
6
51
51
43
44
10
12
14
16
18
20
22
24
26
28
30
6
151
13
11
94
82
8
7
6
61
51
5
7
18
154
123
114
10
9
81
7%
71
61
6
100
8
61
51
5
41
4
31
31
3
8
20
17,
141
121
111
101
91
9
81
74
7
200
161
134
111
101
81
81
74
61
61
51
51
9
231
19
16
141
134
12
10
10
9
81
71
300
241
191
171
151
131
12f
102
91
91
81
71
10
26
211
18
16
14½
13
12
11
104
94
81
400
321
261
221
201
17
16
141
13
12.
111
10
500
401
331
281
251
22.
201
181
16
15
14
13.
No. 14.
No. 18.
DRAWING FRAMES, (3 HEADS EACH.)
DRESSERS, (8 FANS TO EACH DRESSER.)
Drawing.
DIAMETER.
DIAMETER.
10
12
14
16
18
20
22
24
26
28
30
Dressers.
10
12
14
16
18
20
22
24
26
28
30
1
4
34
3
21
2
8
64
6
5
41
4
3t
34
3
1
74
51
5½
41
31
31
34
3
3
12
91
9
71
61
6
54
41
41
41
4
2
14}
111
101
81
71
7
6½
51
54
5
41
3
211
17
15
124
111
10,
91
81
81
71
61
No. 15.
4
281
23½
201
17½
13
14.
121
101
10
91
TWIST SPEEDERS.
No. 19.
Looms.
DIAMETER.
Speeder.
DIAMETER.
10
12
14
16
18
20
22
24
26
28
30
Looms.
48
61
51
41
31
3f
3
10
12
14
16
18
20
22
24
26
28
30
72
91
71
6f
51
54
41
41
4
3ᵢ
3.
3
96
12,
10÷
8%
71
6%
6
5¥
5½
41
41
41
2
51
41
31
31
3
120
151
13
11±
91
81
71
7
6}
6
51
5
4
10.
81
71
6½
53
51
51
41
41
41
31
144
184
15
13
11}
10÷
9
81
74
74
61
61
6
15
13
11±
91
81
72
74
61
6
51
51
168
211
181
15
13.
12
10f
91
9
81
71
61
8
201
17,
141
121
111
10t
9f
81
84
71
7
192
24]
201
171
15
13
12
114
101
91
81
81
10
261
211
171
16
14.
13,
111
10]
101
91
BI
216
29
23f
191
17
15
13
121
111
104
10
9
12
311
26
221
191
174
15
14
13÷
12%
114
10f
EXAMPLE-Required the width of a counter-belt to drive 6 cards,
No. 20.
the diameter of the smallest pulley being 20 inches. Find B in the
column marked Cards;" opposite to this number in the table, and
under 20 in the column marked " Diameter," will be found 8 inches.
EXAMPLE-Required the width of a counter-belt to drive 1500
Pulleys.
No. MACHINES.
1
2
3
4
mule spindles, the diameter of the smallest pulley being 20 inches.
Find 1500 in the column marked "Mules;" opposite to this number
12
71
15
221
30
in the table, and under 20 in the column marked " Diameter," will
14
6f
13
194
26
16
51
111
161
22f
be found 15 inches, the required width, (or two belts 7 and 8 inches
18
5
10
15
20
wide.)
20
4f
9
13f
18
Table 20 shows the width of the counter-belt that drives the coun-
22
4
81
121
16f
24
31
it
111
15
ter-shaft, from which any number of large size board-planing machines
26
"
7
10+
134
from one to four may be driven. The column marked Pulleys,"
28
"
6f
If
124
shows the diameter of the smallest of the two pulleys on:which the
30
"
6
9
12
32
"
51
counter-belt runs; the column marked 'No. Machines," shows the
81
11t
34
"
51
8
10f
number of machines to be driven.
36
=
5
71
10
Digitized by
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BIRAM'S TELL-TALE.
87
KEAMPLE-Required the width of a belt to drive two board-planing machines, the diameter of the
smallest pulley being 20 inches. Find 20 in the column marked " Pulleys;" opposite to this number
in the table, and under 2 in the column marked No. Machines," will be found 9 inches, the required
width of a counter-belt that drives a counter-shaft, which drives two large size board-planing machines.
EXAMPLE-Required the width of a counter-belt to drive a counter-shaft, which is to drive one board-
planing machine, the smallest pulley being 12 inches in diameter. Find 12 in the column marked
Pulleys;" opposite to this number in the table, and under 1 in the column marked No. Machines,"
will be found 71 inches, the width of the belt.
The following statement shows the surplus power of the belts in the table which refers to this note.
The width of the belt was 18 inches, which run 1500 feet per minute; the angle of the belt was about
45 degrees; the distance between the centres of the drums was 25 feet; the diameter of the driving
drum was 8 feet; the diameter of the driven drum was 4 feet. When the belt transmitted 20 horse
power, it worked quite freely; when the power was increased to 25 horse, it was necessary to make the
belt quite tight; when the power was increased to 28 horse power, it was necessary to apply a tight-
ening pulley, which caused the journals on the driven shaft to heat this statement shows that the
velocity of the belts in the table which refers to this note must not be less than 1500 feet per minute.
From a great number of observations it appears that a belt will last longer when it does not run over
2000 feet per minute.
BENCH-PLANES. See CHISELS AND PLANES.
BENCHES AND BENCH STROPS. See CHISELS AND PLANES.
BENDING AND JOINING.
See JOINING AND WORKING, sheet
b
234
metal.
BEVIL AND PARTING
TOOLS. See TURNING Todis.
BEVIL, mortice, whoel, and pin-
103. See GEARING.
D
BIRAM'S TELL-TALE. De-
H
scription.-Fig. 234 is a side eleva-
tion in section, and Fig. 235, a plan
of the apparatus, (on a scale a lit-
tle less than half size.)
A A is the frame, supposed to
contain the works of a portable
timepiece, of which B is the fusee
F
C is a hollow screw, fixed upon the
frame A, through which the axle
of the fusee is prolonged, being
supported by, and turning in a cir-
cular opening at a, above which the
axle is square, the diagonal of the
square being equal to the diameter
at a; D is a hollow tube, having
a female screw fitted into the bot-
tom, to turn easily upon the male-
screw C; the top of the tube D
B
has a square opening to fit easily
upon the square end of the axle of
the fusee; which axle should pro-
ject about half an inch beyond the
tube D, when in the position shown
in the figure, to receive the key or
e
handle used in winding up the
timepiece E is the barrel or cyl-
inder, round which the registering
K
paper is placed, which should be
made to fit upon the tube D, suffi-
ciently tight to retain its position
wherever placed, but capable of
L
being easily turned round upon the
tube, or slightly elevated or de-
g
OF
G
pressed, for the purpose of adjust-
mg it to the index F, to show the
time of the day, and also to adjust
the registering lines with the prick-
er G. F, the index showing the
time, is a fine wire, placed verti-
X
4
K
cally as near as possible to the cyl-
inder, the ends being secured in a
4
frame attached to A. The top of
Θ
the frame also carries the pricker
G, placed exactly over the wire F,
which is acted upon, and makes an
235
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BIRAM'S TELL-TALE.
impression upon the registering paper, when a finger is pressed upon the stud H; I shows a slight spring,
intended to return the pricker and stud to their position when the finger is removed ; L is a piece of
glass in front of the timepiece, the horizontal section of which is that of a double convex lens, but the sides
vertically are parallel with each other this magnifies the parallel and diagonal lines upon the paper
which show the minutes, horizontally only, showing the time more distinctly to the fraction of a minute;
K K are two pieces of plane glass, on each side of L, for the purpose of throwing more light upon the barrel.
Fig. 236 shows a portion of the registering paper, of the full size, with the shaded lines upon it in-
dicating the days of the week; this paper is of exactly the circumference of the cylinder, and is put
upon a strip of leather, gutta percha, or other flexible material, also of the length and width of the
barrel, to each end of which is riveted a strip of brass, having a projection on each side to catch into a
notch in the projecting flanges of the barrel. When the registering paper is changed, the barrel may
be taken off from the tube D, and the leather and paper from the cylinder; and then a new paper put
on, the ends of the paper being turned underneath the leather, and retained by any adhesive applica-
tion, such as that made use of in postage stamps.
The registering paper is divided vertically by twelve equidistant parallel lines, representing the hours,
and again subdivided between each of the above lines by other finer lines into ten minutes. On the lower
edge of the paper are five parallel lines crossed by two diagonal lines between each of the above sub-
division or ten-minute lines, by which each subdivision is again divided into minutes, the time of the
day being shown by the point when the index wire F intersects these small parallel and diagonal
lines. The shaded lines representing the days of the week are not drawn parallel with the edge of the
paper, but in such a manner that when the paper is fixed round the barrel the shaded lines at one end
of the paper fit opposite the intervals at the other end, these shaded lines and intervals being each ex-
actly equal in width to the pitch of the screw C.
Now, suppose the timepiece newly wound up, and a new registering paper placed upon the barrel at
midnight on Sunday (of course this untimely hour is not necessary, as the operation may be done at
any time of the day.) The barrel will then have been removed from the position shown by the dotted
lines in Fig. 234, to the shaded part above in the same figure, and the pricker G would then be oppo-
236.
M
Su
So
E
Th
Tu
M
12
site the commencement of the underside of the line M, (Fig. 236,) and every part of the underside of
that line would by 12 at noon have passed under the point of the pricker; when the barrel having
made one revolution would also have descended one thread of the screw, and during the next revolu-
tion the upper side of the line M, representing the afternoon hours of Monday, would have passed un-
der the pricker, and so on through the week; the lower side of the line representing each day passing
under the pricker during the forenoon, and the upper side on the afternoon of such day. It is therefore
obvious, that any impression made upon the paper by the pricker, would show the day and the exact
time of day when such impression was made, and when the paper was removed from the barrel the
punctures remaining upon it would be an enduring testimony, to be consulted and checked at leisure, of
the operations recorded upon it during the week.
The uses to which this tell-tale might be applied are various. If as a watchman's clock, it may be
used by several people who are required to be at a certain spot at certain or uncertain intervals. When
erson presses upon the stud, he should be required to make a memorandum of the time by the clock;
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these memoranda he would give up to the inspector at the end the week, who would compare whether
the punctures upon the paper corresponded with the return; and if not, the writer would of course be
detected making a false statement. In an establishment where there are a number of individuals,
and it is desirable to ascertain the time of their attendance, they might be required to write their names,
and the time of their arriving, in a book, at the same time pressing the tell-tale; when, although sev-
eral might arrive and sign so near together that the punctures upon the paper might run one into an-
other, yet the time between the first and last would be distinct, and if the names were written in suc-
cession, it would be evident that they had been written during the time between the first and last
puncture. Again: any individual leaving an establishment during the day, might be required to write
his name in the same way, with the time of his leaving and returning, at each time pressing upon the
tell-tale, which would be a great check against a person absenting himself improperly, or being absent
too long. It might also readily be applied to registering the performance of a steam-engine, or other
machinery, by so connecting it with the machinery that the pricker should puncture the paper after a
certain number of strokes of the engine, or otherwise.
The tell-tale, as in the engravings, is shown attached to a portable timepiece, regulated by a balance
escapement; but it is applicable also to a common eight-day clock, with slight modifications.
BIRCH. See WOODS, varieties of.
BISMUTH. See MINERAL KINGDOM, materials from used in the mechanical and useful arts.
BITS AND BRACES. See BORING Tools.
BITTERNUT-WOOD. See WOODS, varieties of.
BLACK BOTANY-BAY WOOD. See WOODS, varieties of.
BLASTING UNDER WATER. Paper on the application of Gunpowder as an instrument of engi-
neering operations, exemplified by its use in blasting marl rocks in the River Severn.-The object of the
proposed works was to increase the depth to 6 feet of navigable water during all seasons. Above Wor-
cester, the additional depth is obtained partly by dredging, but chiefly by a series of four weirs, varying
between 300 and 400 feet in length, with side-locks for the traffic. Between Worcester and Gloucester
(a distance of 29 miles) it is proposed to obtain the required depth, partly by contracting the channel
by embankments of fascines, and partly by dredging. The shoals to be removed by dredging are gen-
erally isolated, varying from 100 yards to half a mile in length, and they require excavating to a depth
of from 3 to 5 feet. A large portion of these shoals consists of alluvial gravel, without flints, but prin-
cipally of quartzose and granitic pebbles, varieties of porphyry and of compact and granular sandstone.
This material, although very hard in some places, offered no engineering difficulties. Other shoals con-
sist of denuded beds of hard red marl; this material being found in every instance, when the river im-
pinges upon the eastern or western limits of its valley. In most places it was so hard, as to render its
removal by the dredging machine quite impracticable.
That part of the river Severn, above described, traverses nearly north and south the great plain of red
marl of the new red sandstone formation, the bed of the river from Stourport to about a mile below Holt
bridge, near Ombersley, being formed through the upper strata of the new red sandstone; upon this lies
the great bed of red marl, (in places saliferous,) dipping at a small angle, but irregularly, to the south-
east. The river traverses the whole of this strata, which is probably more than 1000 feet in thickness,
passing through the upper strata, and entering the lias formation above Gloucester.
The red marl is generally considered by geologists to be formed from the debris of older rocks, and it
appears to be totally devoid of organic remains. It lies generally in beds, rarely exceeding 15 inches in
depth, and often much less. It is divided occasionally by strata of greenish gray marl, and near the
upper part of the formation by thin, but very hard, beds of shaly or imperfect lias.
It is difficult to describe the comparative hardness of materials, but when it is stated, that in many
places it was impossible to cause a steel chisel-pointed boring tool to enter it by any ordinary exertion, by
Is and, from a boat, it will be conceived that it could not be readily raised by dredging. After exposure to
the action of the air it breaks up into small fragments, almost like the slaking of lime, so that solid blocks,
which could only be broken by the application of considerable force into sharp-edged fragments, would,
in the course of a few days, fall to pieces and afford no criterion of its hardness in an undisturbed state.
When the dredging machine was tried upon one of these marl shoals, it was found impossible to raise
above 50 or 60 tons per day, and that with constant risk and repeated accidents to the machine; but
such rate of progress was totally incompatible with the required progress of the work. Attempts were
first made to break it up by driving iron bars into it, and prizing it up, but this plan did not answer. A
second attempt was made to loosen it with a very strong plough, something like a 'subsoil" plough,
which was proposed to be pulled through the marl by a powerful crab fixed on a barge, the plough being
guided by a strong pole; the effect produced was, however, 80 superficial, and the expense of labor was
so great, that this method was also abandoned, and experiments were made to ascertain the effect and
probable cost of using gunpowder. These were 80 satisfactory, that it was determined to blast all the
marl shoals, previous to dredging them. In January, 1845, as soon as the requisite materials and estab-
lishment could be prepared, this operation was commenced, and has since been carried on with no other
interruptions than those occasioned by freshes in the river; the total length of blasting required (about a
mile and a half) being now completed, and a considerable portion of the marl since dredged up, at the
rate of 200 or 300 tons per day, with perfect facility.
The most economical method of using powder, to break up a depth of rock like that described, would
probably be to obtain a face of the required depth at one end of the work, to put in a row of shots at
the back of it, and after each discharge to remove the loosened marl; continually repeating the process
but this method would have been open to many serious objections. The dredging machine and the
blasting gang would have been constantly waiting for each other, and having but two dredging machines
to perform the work, it was of great importance to economize their time in every possible way. By such
proceedings also, a constant obstruction to the navigation would have been created, equal to the whole
width of the new channel. The number of men that could have been employed in blauting would also
12
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BLASTING UNDER WATER.
have been very limited. These objections, in this particular instance, far outbalanced any little saving
of gunpowder. It was therefore determined to put in perpendicular shots, throughout the site of the
channel, at such distances as experience might prove to be best, and proceedings were commenced with
spaces of 6 feet from centre to centre of the shot-holes.
Six rafts were used as stages to work from they were each formed of four baulks of timber, about
40 feet long; the baulks, placed in pairs, were secured at a distance of 4 feet apart, by cross-pieces, 6
inches square, well spiked to the baulks at intervals of 6 feet; these were covered with deals 3 inches
thick, laid lengthwise of the raft, a space of 12 inches in width being left open along the centre. The
ends of the rafts were provided with strong ring-bolts to moor by. These rafts were confined to one
bank of the river by ropes, and retained at the required distance from it by a series of "sets," or booms,
abutting against the bank. At the up-stream end of the raft was a large barge, fitted up as a black-
smith's shop, for the necessary repair of the tools, with dwellings for the watchman, &c. The bows of
the barge were strongly fortified, and a strong oblique boom of large baulks reached from it to the shore,
80 as to protect the whole fleet from the craft coming down the river. At the down-stream end was
another barge, fitted up as a powder magazine, and as a shop, furnished with every necessary for the
manufacture of the cartridges, and for the storing of their material.
The first operation consisted in placing and securing in their proper positions, the pipes through which
the holes were to be bored. Small stakes, painted with a series of numbers, were first driven into the
bank, parallel to the work, at distances of 6 feet apart; as far behind them as the slope would allow, was
another row of stakes parallel with the first, 80 that a line drawn through two stakes would be at right
angles with the river, and a person standing behind the two stakes could readily direct the workman when
to lower the charge-pipe, which was then secured in its place, in the opening of the raft, by a timber
dog," driven into the raft on each side of it. The pipes were of wrought-iron; they were 31 inches in
diameter, three-sixteenths of an inch thick, and 9 feet long. Where the marl was so deep as to require
8 or more pounds of powder, it was found that the cartridges of such diameter as could be used in these
small bores were so long as to lose part of the effect of the gunpowder; subsequently, pipes of 4 inches
diameter were used with advantage. Two collars, half an inch square, were shrunk on them near the upper
237.
23d
end, for the purpose of retaining a rope, by which they were secured when the charge was fired. When
the depth of the water increased, these pipes could be lengthened 4 feet by an additional piece, prepared
for that purpose; this joint was made by shrinking on a collar, 6 inches long, over the joint. The pipe
being in its place, was driven through any gravel that might remain, and a few inches into the marl The
gravel was generally so thick upon the marl, that it was requisite first to remove it by means of the
dredging machine. To protect the thin edges of the pipes whilst being driven, a cast-iron cap, or plug.
was used, which received the blows from a heavy wooden beetle; the interior of the pipe was next
cleared of any sand, or gravel, that might have entered while putting them down. The principal tool
used for this purpose was an iron bucket or cylindrical tube, 2 feet in length, of as large a diameter as
would pass down the whole; it was furnished at the bottom with a valve opening inwards, and was
jointed to a round rod, of the requisite length, half an inch in diameter, and when used with a pumping
motion, quickly brought up whatever could not enter at the valve.
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The boring then commenced a gang of three men being stationed at each pipe. The first operation
was that of the jumper, which was made with a single steel edge, a little rounded. The jumpers were
of round iron, 11 inch diameter, except 2 feet in length at the lower end, which was 11 inch diameter.
For general use they were 15 feet long, and weighed about 52lb. each; after working them till they
were nearly set fast, an auger was inserted to raise the plug of loosened marl and to render the hole
true. The shell of the auger was 20 inches long and nearly closed up, the better to retain the loosened
borings.
The shot-holes were bored two feet below the proposed bottom of the dredging, as it was expected
that each shot would dislocate, or break into small pieces, a mass of marl of a conical or parabolic form,
of which the bore-hole would be the centre, and its bottom the apex, 80 that four adjoining shots would
leave between them a pyramidical piece of marl, where the powder would have produced little or no
effect. By carrying the shot-holes lower than the bottom of the intended dredging, the apex only of this
pyramid was left to be removed, and in practice this was found to form but a small impediment, Figa.
237 and 238. A second reason was, that if the removal of the shoals should cause the level of the sum-
mer water to fall lower than was expected, the marl might still be found sufficiently broken to enable a
greater depth to be obtained without further blasting.
The cartridges, or charges, were formed of strong duck or canvas bags, somewhat tapered at the bottom
these were filled with the required charge of powder, varying from 2lb. to 4lb., according to the depth
of the marl; the weights of powder used for depths of 4 feet, 4 feet 6 inches, and 5 feet, were respect-
ively about 2lb, 3lb,, and 4lb. The end of a coil of Bickford's patent fuse was inserted to the centre of
the powder, and the neck of the bag was carefully gathered up round the fuse, and well tied with small
twine. If the cartridge was small, it was then dipped into melted pitch, which had about one-fourth of
tallow melted with it, or otherwise the melted pitch was ladled over it, till it was uniformly coated; in
this state, the cartridges were hung to drain and stiffen. When hard, they were well rubbed over with
tallow, and lastly powdered over with dry whiting. The tallow, whilst it ensured the stopping of any
little cracks in the pitch, facilitated the passage of the cartridge down the hole; the whiting also pre-
vented the pitch from adhering to any thing. It has already been stated, that the powder was ignited
by means of Bickford's patent fuse; but as this material is never made in lengths exceeding 48 feet, it
was found expedient, in order to save waste, to use the whole coil, cutting it off at the requisite length
when absolutely in the hole, and using the remainder in the same way till the whole was used up.
The charge was carefully pushed down into the hole by a wooden ramrod of suitable diameter, with
the end rounded; the same instrument was used for ramming down the tamping. The material found
to answer best for this purpose, was the small fragments of hard marl, separated by the action of the
weather from the lofty escarpment at each of these shoals; this was gradually filled into the holes, and
rammed solidly, till the bore was full up to the surface; the timber-dogs which held the pipes were then
removed, the pipes were loosened from the marl, ropes were attached to the pipes and to the raft, or to
some loose pieces of timber, and the shots were fired. Generally there was little external effect beyond
the pipes being lifted a few inches, though sometimes they would be blown up several feet, and occa-
sionally the water would be forced up through the pipe to a height of 40 or 50 feet. All the gangs
commenced their holes in the morning, and they were generally all ready to fire at the same time, which
was always done, as it caused least interruption to the work.
It was a rare occurrence for a shot to miss fire-probably not once in a hundred shots the failure arising
generally from a leak at the joint between the fuse and the bag. If the leak was not very serious, the shots
were often saved by the following somewhat singular expedient. An iron bar, five-eighths of an inch in di-
smeter, and of sufficient length, pointed at the end, was kept in readiness, and when required the end
was heated red hot, put quickly through the water into the tamping, through which it was driven as
rapidly as possible into the powder, which in nine cases out of ten it was still hot enough to ignite.
The result of the whole work being invisible, great care was necessary in order to prevent mistakes
and omissions. As each shot was ignited, a red mark was laid against its corresponding stake upon the
bank; when it had gone off, each shot was carefully examined with a steel chisel-pointed searcher, to
prove that the required effect had been produced to the determined depth; when so found, the red mark
was insurted into the top of the stake, as a certificate of that shot having passed examination: the
numbers so certified were then transferred to a book kept for that purpose, and if a shot was found in-
effective, another was put in the same place.
To afford space for the workmen, every alternate hole was first made, and afterwards those which had
been left between them; one line being completed, the whole line of raft was moved 6 feet outwards to
the next line, and so on till the required width was obtained. The whole establishment was then dropped
down the length of the rafts, and the process was repeated. When the men had become used to the
work, each gang would sometimes get down four shots per day 80 that with fifteen gangs, sixty shots
have been fired per day.
It may be objected to the use of the patent fuse, that the ignition of a number of charges simultane-
ously by the galvanic battery would have produced better effect, at less cost, and in a more scientific
manner. The author commenced the work under a different impression, and subsequent experience with
the battery has not altered his opinion. When it is required to separate a large stone from its bed in
the quarry without breaking it, nothing can be better than the numerous simultaneous discharges, which
can only be obtained by the use of the battery but the object in this work, on the contrary, was to break
the mass to pieces as much as possible, which it is conceived would be more likely to be effected by
distinct discharges.
Then as regards cost: the patent fuse No. 8, carriage included, cost six-tenths of a penny per foot; if
the average length is taken at 15 feet, that is just nine-pence per shot, a sum which would barely pay
for making the arrangement of wires necessary for the galvanic ignition. It was also found, from the
compressible nature of the canvas cartridges, that the arrangement of the wires was very liable to be
disturbed, during the insertion of the cartridge into the hole, or by the subsequent ramming of the tamping.
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BLAST-FURNACE
After considerable experience, therefore, and the use of nearly 100,000 fect of the patent fuse, it has been
found satisfactory.
There now only remains to be given the cost of the operation above described. The first cost of the
establishment or plant, sufficient for 6 months' work, was $1500. This includes the waste and use of
timber, in the raft, stages, booms, &c., hire of barges, and cost of fitting them up for the work, cost of
pipes for boring, iron and steel for tools, deducting estimated value when done with, sundry ironmongery,
waste and loss of ropes and other small stores.
More than ten thousand shots have been fired. This number gives just one shilling per shot, as the
proportionate share per shot of the cost of the plant; this would of course be much less if the work was
to be continued.
BLAST-FURNACE This invention relates to the construction of blast-furnaces, and to various
other arrangements connected therewith. Heretofore, it has been the custom, during the process of
smelting iron-stone or ore, to allow the charge to remain some days in the furnace for the purpose of
cementing, as it is termed; such being understood to mean the distribution of metal over the surface
of the material, so that it may receive the full force of caloric evolved by the reverberation in the
smelting-furnace. The present means, however, employed by the patentee for more effectually carry-
ing into operation his improvements hereafter explained, constituting the novelty of this invention,
consists in the numerous advantages resulting from the more perfect combination of certain parts, by
reducing the height of the furnace very considerably, and arching in and producing a better arrange-
ment at the top, so that the unconsumed smoke, which would otherwise pass off, is prevented, gener-
ating thereby greater heat than hitherto. Fig. 239 of the engravings annexed, represents a sectional
240.
241.
239.
d
7
d
d
c
h
c
b
b
244.
242.
243.
d
elevation of an old furnace, such as is now in use; the construction of which will be readily under-
stood by reference to the engraving; a is the hearth; b, the commencement of the boshes, and c the
shaft d is the crown for supplying the furnace; e is the lining of the furnace, composed of fire-brick;
and f, the outer casing of stone or other suitable material; g g are the tuyeres, surrounding the base
in the figure just referred to; the materials are thrown in from the top, which is open to the passage of
the flame and unconsumed gases, instead of arresting their progress, for the production of greater heat
during the smelting process. Fig. 240 represents a modification of the former arrangements, consisting
only in the dome or arched top placed just above the landing h; the object of which is to deflect down
the rays of heat, and the unconsumed gases evolved; d shows two dampers, for the purpose of regula-
ting the draft, by opening or closing the crown of the dome; i i are slots or apertures, passing trans-
versely down by the sides of the landing, for supplying the furnace. Fig. 241 represents a sectional
elevation of a blast-furnace of the improved construction, the form of which the patentee considers an
essential feature, being greatly diminished in height, rendering, thereby, the operation of raising the
materials for forming the products .less troublesome than hitherto; the mode of working, and the
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arrangements generally, are the same, from the hearth upwards, with the exception of the boshes; the
sides are nearly vertical, with a slight curve at the shoulder or bending; the form of the dome or cover,
as before described, for concentrating and retaining the heat, is of such a material and construction,
that the effect produced during the process of smelting iron-ore, or other metallic substances, causes a
quicker deposite of the products, enabling such to be entirely withdrawn at shorter intervals, by the
increased intensity of the caloric. Fig. 242 shows a sectional plan view of Fig. 241, taken through
the dotted line at b; g g, as in the former instance, denote the tuyeres, passing through the lining e e,
the outer stone-work ff allowing any communication being. to them by means of the recesses
formed in the masonry j is described as the tapping-hole. The chief novelties in these arrangements
relate, first, to the improved form, which is considerably less in height, and greater in width, employing
a proportionate number more of tuyeres, as well as offering facilities for feeding the furnace, by de-
creasing the rise to the landing, as also for an apparatus employed for that purpose, shown at Fig. 243;
6 is the receptacle for the materials; b a couically-shaped bottom, mounted on a centre, having a
weight, e, placed upon the end of the arm or lever to which it is attached, for the purpose of keep-
ing it closed, and counteracting the weight of the trap or moving bottom; c is another, of a large
description, situated immediately beneath it, with a weight f, and lever, as in the other instance;
d is the crown of the furnace. The action is as follows: the materials to be placed in the blast.
furnace, are directed through the chamber a, which, by the use of the conically-formed trap or bottom,
are deflected off from the surface in an outward direction, and by falling on the larger one, beneath,
caused to descend, and be deposited around the sides of the furnace, where a greater degree of caloric
is given off. Fig. 244, represents a blowing-apparatus, which consists of an upright frame-work, to the
top portion of which the blowing-apparatus is fixed, the other end having a sliding-bar working on the
side-rods b; c is a small cylinder, fixed to the bed-frame, with piston and connecting-rod attached
vertically to the lower portion of the blowing-apparatus; d is the steam or ingress pipe; e, the blast
branch-pipe, communicating to the tuyeres. In putting the machine into operation, it is first ne-
cessary, by suitable valves, to admit the steam below the cylinder g, the effect of which upon the
blowing-apparatus, will be to cause it to move upward, and impel the air from within, through
the tube e, into the furnace; ff are springs for bringing down the apparatus in readiness to be again
raised by the steam-piston. The patentee describes an improved tuyere, capable of passing into the
furnace, and being kept cool without the application of water-passages through them, using for such
means currents of air instead; also for combining and arranging blowing-cylinders having steam-
engines attached; the novelty of which consists in uniting two air-pump cylinders, with inlet and outlet
valves, communicating to the tuyeres, and working the same backwards and forwards by the up and
down stroke of the piston, as heretofore, the rod of which is attached to the pistons of the air-pumps,
which are so constructed, having buffers of elastic substances, such as Indian-rubber, that when the
piston completes each alternate stroke, it shall be prevented striking the ends of the cylinder by the
interposition of such means, whereby a pressure of air is maintained of uniform strength without the
employment of fly-wheels. Lastly, for the mode of applying two or more fans placed on the same
shaft, and made to revolve by a rotary steam-engine in such a manner that the air or blast from the
first shall enter into the second, and from the second into the third, and so on, if desirable, thus
accumulating by such means a more powerful blast to be passed into the furnace than yet employed.
The patentee, after describing the object of his invention, and the manner in which the same is
to be carried into effect, states, that he does not confine himself to the whole of the particulars,
so long as the important peculiarities of his invention be retained; but he claims, first, the mode of
constructing bla-t-furnaces in the peculiar manner set forth; secondly, for improvements in the con-
struction of tuyeres, so as to keep them cool by the passage of air through them; thirdly, for the mode
of arranging and combining blowing-cylinders having steam-engines attached, whereby the pressure
of air is kept uniform, without the employment of fly-wheels; fourthly, for the means of regulating
blasts of air to blast-furnaces, by the pressure of steam and springs; fifthly and lastly, for the appli-
cation of two or more fans on the same shaft, when receiving motion from a rotary steam-engine placed
on teb shaft.
BLAST-FURNACES. See CASTING AND FOUNDING.
BLAST-PIPE A pipe employed in locomotive engines to convey the waste steam from the cylin-
ders up the chinney, and to urge the fire. Its invention is generally ascribed to Mr. George Stephenson,
and it IS supposed to have doubled the power of the engines at the period of its introduction.
BLASTING. The operation of detaching and separating blocks of stone or earth from their natural
or quarry beds, which was usually performed in former times by the following process:-Long wooden
wedge were driven, in a very dry state, into holes prepared for them, and previously well heated; a
quantity of cold water was then poured over the wedges, which, upon becoming thoroughly saturated,
swelled and caused a fracture of the rocks. The same effects are now generally produced by the
exploding force of gunpowder, which was first used for that purpose about the year 1820. A hole is
first driven into the earth by a jumper, or chisel, which is held in a proper direction by one man
while another strikes it with a hammer, the former turning his instrument at every blow, by which it is
soon made; and it is formed of various depths, from 1 to 3 feet, according to circumstances. If water
appears in the hole, some stiff clay is crammed in, by which it is absorbed, and the fissures through
which it entered filled up. When the hole is of some considerable size, and of great depth, a long
jumper succeeds the first, which is 6 or 8 feet long, and pointed at both ends, with a projecting bulb
in the middle, which serves as a handle for the men to lift it up, upon which it is dropped into the
hole, and being heavy, perforates the rock. A hole of 5 feet depth may be formed without much
difficulty by a succession of these falls. The gunpowder, enclosed in paper, is then introduced into the
bottom of the hole, which is properly adapted for it. A thin copper rod is now connected with it, and
some soft impervious substance crammed into the remaining part of the hole when the rod is withdrawn,
by which a vent is obtained, connecting the charge with the touch-hole, into which a fusee is dropped
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BLOCK MACHINERY.
and lighted, which completes the operation, when the men retire. Crooked pieces of iron are also
semetimes introduced into the bottom of the hole to assist in detaching the masses of rock. The natural
stratification of the rock is of course attended to, as a horizontal blast will frequently bring down ten
times as much as a vertical one.
The blasting of rock under water is usually performed by the diving-bell, the communication with the
gunpowder being effected by means of a tin tube. A galvanio battery has also been lately employed
for that purpose, and with considerable success. A much greater degree of safety is insured by this
system of explosion.
BLOCK IN COURSE. See RAILWAY ENGINEERING.
BLOCK MACHINERY. The machinery at the dock-yard, at Portsmouth, invented by Mr. Brunel,
for manufacturing blocks, is deservedly celebrated. The following is a concise account of it:-The
machines are separated into four classes.-1. The sawing-machine, for converting the large timber into
proper dimensions for the small machines to operate upon. 2. The machinery to form the shell.
3. The sheave-forming machines. And 4. The pin-forming machines. The machinery is capable of
completing three sets of blocks of different sizes at the same time, and is worked by two steam-engines
of 30-horse power each. The order of the process is this: The elm-trees are first cut into short lengths,
proper to form the various sizes of the blocks, by two large sawing-machines, one a reciprocating, and
the other a circular saw. These lengths of trees are next cut into squares, and ripped or split up into
proper sizes by four sawing-benches, with circular saws, and one very large reciprocating saw, which is
employed in cutting up the pieces for very large blocks. The scantlings of the blocks being thus
prepared, the next process is that of
Making the Shells. The centre hole for the pin of the sheave is first bored by a centre-bit in the
boring-machine, whilst a number of others, corresponding to the number of sheaves which the block is
245.
0
in
2
q
re
1
4
W
b
b
W
y
I
to contain, is bored at right angles to the former, to admit the first stroke of the chisel, and, at the same
time, form the head of the mortises. The blocks are then removed to the mortising-machine; here they
are firmly fixed to a moveable carriage, beneath cutting chisels, set in a frame moving up and down with
extreme rapidity. Each time that the chisel-frame ascends, the moving carriage advances a small
space, bringing a fresh portion of wood under the chisel, until the mortise is cut to the proper length.
when the machine is stopped with the chisel-frame at its highest elevation. The chips cut are thrust out of
the mortise by small pieces of steel projecting from the back of the chisels, which are also armed with
two cutters, called scribes, placed at right angles to the chisels, which mark out the breadth of the chip
to be cut at each stroke, and at the same time leave the sides of the mortise so true as to require no
further trimming. The corners of the block are next taken off at a circular saw table, and it is then
removed to the shaping-machine; here the blocks are fixed in grooves in the peripheries of two equal
wheels fixed upon the same axis, the distance between them admitting of regulation to suit various
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sizes of blocks, each wheel having ten grooves, 80 that ten blocks are shaping at once. These wheels
are made to revolve with great velocity against a cutter set in a slide-rest, which, moving in a curved
direction to the line of the axis, cuts those outward faces of the block to their required figure. As soon
as the tool has traversed the whole length of the block, the machine is thrown out of gear, and the
blocks are (without removing them) each turned one-fourth part round, and another fourth-part of their
surface is exposed to the cutter. When the remaining portions of the surface are shaped, the ten blocks
are removed, and the last operation is performed by the scoring-machine, which, by means of a cutter,
scoops out a groove round the longest diameter of the block deepest at the ends, and vanishing at the
central hole for the pin. There only remains to remove any little roughness, and give the surface a
kind of polish, which is done by hand, and the shell is then complete.
of the Sheaves. These are mostly made of lignumvitæ, which is cut into slabs of a proper thickness
by circular-saws, and then removed to a crown-saw, which bores the centre hole, and at the same time
reduces the circumference to a circular figure. The abeave is then placed in the coaking-machine,
which forms a recess on each side of the block to receive the bush or coak, which is a triangular form,
with the ends rounded off. The machinery for effecting this is extremely ingenious, and acts with such
accuracy, and the coaks are cast 80 true, that a single tap with a hammer is sufficient to fix the coak in
its place. Three holes are then drilled through the two coaks and the intervening wood, and pins being
inserted in the holes, they are placed under the riveting hammer, which strikes the pins with a velocity
proportioned to the pressure which the workman exerts upon the treadle. The centres of the coaks
are next broached by a steel drill, and the sheave being removed to a lathe, which cuts the groove on
the periphery whilst it faces the sides, the sheave is completed. There remains now only the iron pin,
which, passing through the two sides of the shell, serves as the axis on which the sheave turns. These
pins are also made, turned, and polished, by a machine for the purpose; so that, with the exception
of strapping by rope or iron, the block is now complete.
Although the foregoing account of the operation of the several machines will convey to the intelligent
reader a sufficiently clear idea of the whole process by which the blocks are made, we doubt not that a
representation of some of the principal machines will be acceptable to our readers. To give engravings
of the whole of them would cause us to extend this article to too great a length; as, independently of
the various saws by which the trees are cut up into blocks and slabs of the proper dimensions, (which
saws may be considered as applicable to other purposes,) there are a great variety of machines
employed in the subsequent operations. These may be said to constitute the block-making machinery,
properly so called; and from these we have selected two of the principal, to form the subject of the
accompanying engravings. Fig. 245 is a side elevation of the mortising-machine, in which the mortises
for the sheaves are cut. a a the bed of the machine; b a sliding carriage c the block to be mortised,
securely held in the sliding carriage by the screw e; f one of the cutters, the number of which depends
on the number of sheaves the block is to contain; g the cutter-frame, moving vertically in guides
fastened to the two front pillars of the machine, one of which pillars is removed in the figure, in order
to show the cutter-frame; h a guide-rod attached to the upper part of the cutter-frame, and moving in
a collar j; k connecting-rod, attached at the upper end to the cutter-frame, and at the crank 1 fixed
upon the shaft m, which is driven by a strap from the steam-engine passing round the drum n, which is
bolted to the fly-wheel O. The fly-wheel is loose upon the shaft, which is attached to, or detached from,
the fly-wheel, by a friction-clutch p, which enters the conical interior of the drum n, and which is moved
by the levers qq; r is a double-threaded screw, by which the sliding carriage is advanced it works in
a nut 8, which turns in a bearing t; to this nut are attached the ratchet-wheel v and the cog-wheel to ;
= a pinion acting upon 10, and turned by the handle y, and only used to bring the blocks under the
cutters for the first cut, after which the carriage is advanced by the machine in the following manner
Upon the shaft m is an eccentric 1, which acts upon a roller 2, in a vertical lever 3, to the lower end of
which is jointed a horizontal bar 4, which has a tooth acting upon the teeth of the ratchet-wheel, 80 that
- each revolution of the axis the eccentric thrusting out the upper end of the lever 3, moves in an
opposite direction the ratchet-wheel v, which, by means of the nut 8, turns the screw, and advances the
sliding carríage, 80 as to bring a fresh portion of the block under the cutters. When the whole length
of the mortise is cut, the advance of the carriage further is prevented as follows: The extremity of the
bar 4 is prolonged beyond the ratchet-wheel, and rests upon the lever 5, which turns upon a pin in one
of the upright columns of the frame. The lever 5 is supported by the curved end of the lever 6, the
other end of which rests upon an adjustable slide 7, which is screwed to the sliding carriage, and which
is 80 fixed, that when the mortise is completed, the long arm of the lever 6 is no longer supported by
the slide; the long arm of the lever consequently descends. and, by its descent, raises the lever 5, which
lifts the bar 4 clear of the teeth of the ratchet-wheel Fig. 246 is a side elevation of the shaping-
machine a is a large circular rim, or chuck, firmly keyed upon the shaft b; a similar chuck c, (which
cannot be shown in the drawing,) is placed upon the shaft behind a. This chuck is not made fast, but
may be set upon the shaft at any required distance from a to suit the different sizes of the blocks; dd
are stay-bolts passing through the chucks a and c, and having nuts at the back of c to retain it at the
requisite distance from a; ee are the blocks which are to be shaped; they are retained between the
two chucks a and c, as follows ff are a number of short maundrils, set in the chuck a, and each carrying
on the farther end a small cross, the extremities of which have two sharp steel rings; in the chuck c is
a screw, opposite to, and concentric with, the maundrils ff; the inner end of these screws having a
-harp steel ring loosely fitted upon them. Each block, in the operation of boring the holes previous to
passing to the mortising-machine, has had the line of its axis determined, by the marks of two steel
rings impressed on one end, and of a single ring upon the other. The marks of the two rings are
applied to the steel ring on the cross, and the ring on the screw is advanced by the screw to the single
mark on the other end of the block g is a slide-rest, supported upon the bed h, and attached to the
radial bar j, which turns upon a centre directly beneath the line of the axis of the shaft b; k is the bar
carrying the cutter I, and sliding in a mortise; in a steel spindle, passing through a socket in k, and
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BLOCKS.
having a small horizontal roller n fitted upon its lower end o one of two pillars supporting two curved
bars P q, called shapes; the curve on one bar determining the shape of the faces of the blocks, and that
of the other bar the shapes of the sides of the blocks. r is a lever by which the cutter-bar is moved
along its mortise, 80 as to cause the roller n to press against one of the shapes p or q; 8 is a bar
attached to the slide-rest, by which the rest is made to traverse the bed h, describing a portion of a
circle of which the pivot of the radial bar is the centre. The operation of the machine is as follows
The chucks being filled with a number of blocks corresponding to the number of maundrils, the chucks
are set in motion by a strap from the engine passing round the drum t, keyed upon the shaft b. The
cutter l being previously adjusted to the proper distance, the attendant holding the bar 8 in his right
hand, causes the slide-rest slowly to traverse the bed h, whilst, by the lever r, held in his left hand,
he keeps the roller n in contact with the shape p or q. and consequently causes the cutter I to describe
a curve similar to that of the shape; and that face of the blocks which is exposed to the cutter revolving
with extreme rapidity against the cutter, is cut to a corresponding shape. When the first side 18
completed, the blocks and the chucks are stopped, and the blocks are turned one-lourth round, so as to
present the next line to the cutter. This is effected by the following means: On the outer end of each
maundril is fixed a worm-wheel v, upon which an endless screw upon the outer end of the spindle W
acts; upon the other end of each spindle is fixed a bevelled pinion y, gearing with a bevelled wheel =
fitted loose upon the axis. When it is required to turn the block, the wheel x is locked to the frame by
246.
od
6
C
LTV.
a catch-pawl, (not shown,) and the attendant turns round the chucks a and c four times, and the bevelled
pinions revolving round the wheel x cause the spindles on which the endless screw is cut to turn the
worm-wheels one-quarter round. The roller n is then by a simple movement pushed down, so as to act
against the lower shape; the chucks are again set in motion, and the slide-rest being made to traverse
back over the bed, the second face is shaped, and the operation is repeated for the other two sides.
BLOCKS, in the Navy, and Marine Architecture, a species of pulley very extensively used for moving
heavy weights, by means of ropes or chains passing over the pulleys; also occasionally in architectural
and other works. A block consists of one or more pulleys, called sheaves, which are generally formed
of lignumvitæ, or some hard wood inserted between cheek pieces, forming hat is called the shell of
the block, and turning upon a pin passing through the shell and the centres of the sheaves. Blocks are
of various forms, each having a particular name; the following cut represents a common single block
a is the shell, b the sheave, c the pin. Blocks are suspended by straps, either of rope or iron; the
latter are called iron-strapped blocks, and have frequently a swivel-hook. A combination of two
blocks, one of which is attached to the load to be raised, is called a tackle, and the power is to be esti-
mated by the space through which the fall (which is that part of the rope to which the power is applied)
passes, compared with the space through which the load is raised, deducting for friction, which is great,
owing to the rigidity of the ropes, and the small diameter of the sheaves; these, for nautical pur-
poses, are necessarily limited by considerations as to weight and space. The friction is also consid
erably increased, in certain circumstances, under which blocks are applied. When there is more than
one sheave in the same block, the fall comes last over the outside sheave; and that sheave, if the
exertion of power be in a line nearly parallel to the direction in which the load is drawn, always
endeavors to get in'o a line with the point of suspension; for the great friction to be overcome pre-
ven ing the equal transmission of the power throughout the combination, and the outside sheave
having to sustain not only the pressure of its own share of the load, but also the additional strain
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BLOCKS.
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sufficient to overcome the friction of the other sheaves, and
the vis inertise of the entire load; it must therefore, be con-
248.
247.
siderably depressed, and in consequence of this oblique di-
rection of the block, the lateral friction of the sheaves be-
comes so great, as in some cases nearly to equal the power.
Figa 247 and 248 represent blocks so constructed as to al-
low the fall to pass over the middle sheave, by which means
it will be immediately beneath the point of suspension. Fig.
a
247 is the invention of the celebrated Smeaton, who em-
a
ployed blocks of this description in erecting the Eddystone
Lighthouse. The upper block a contains six sheaves ranged
in two tiers, and the lower block b contains also six sheaves,
also ranged in two tiers; the lower tier of sheaves in a, and
the upper tier of sheaves in b, being more than two diameters
of the rope smaller than the other sheaves, the mode of reev-
l
ing the rope is as follows: Beginning in the middle, the rope
is reeved over the large sheaves as far as it will go; thence
going to the first of the smaller sheaves, they are reeved
throughout; thence again to the outer one of the remaining
large sheaves, and ending upon the middle sheave of the up-
per block. The principal objection to this method is, that it
requires a combination of at least twelve sheaves, and is not
therefore applicable to general purposes. The construction
"
shown in Fig. 248 can be applied to any number of sheaves
from four upwards. The cut represents a pair of blocks of two
sheaves each. To the upper block, a, is attached another block
b, the sheave of which stands at right angles to the former,
and is called the cross-sheave; the lower block c contains
two sheaves abreast, (shown diverging,) in order that the cross-
sheave may not be of a very small diameter. The method of reeving is to begin upon the middle upper
sheave, and when arrived at the outer sheave, to pass to the cross-sheave, which carries the rope over
to the outer sheave, on the opposite side, and then proceed again in the order of the sheaves.
The annexed figure represents an improved cat-block. The advan-
tages which this block possesses over those in common use, may be
249.
thus stated In all large class ships, the unwieldy nature of the usual cat-
block requires that two men should be sent out on the anchor, a most
perilous service in rough weather; whereas this only requires one man
at any time, because he has not to sustain the whole weight of the
block, as in the former case, but only that of the hook. And in vessels
smaller than line-of-battle ships, in blowing weather, when the ship
pitches heavily, the anchor may be hooked without a man going on
it, by his standing on the head, and guiding the hook of the block to
the anchor, by a staff and hook, similar to a boat-hook. This facility
is gained by the mobility of the swivel in its socket, 80 that the man
has not the weight of the block to turn, in order to insert the hook
in the ring of the anchor. Should the anchor, when hooked in the
dark, or otherwise, cause a turn in the fall, the hook being on a
swivel-joint, the turn will come out before the strain comes on the block
and when the anchor is foul, it can also be hooked with great facil-
ity. In service I have seen the wooden cat-blocks swell 80 much in
cold climates, that the sheaves have become immoveable; this being
of metal, is liable to no such inconvenience. By merely having a
spare socket or two fitted with hooks of various sizes, it may take a
strap for gear-blocks, or it may be converted into a lashing-block with-
out the hook and socket, but with the socket-bolt. In the figure,
which represents a perspective view of the block, it will be seen that
the hook, instead of being formed in one with the strap, turns with a
swivel-head, in a socket which hangs from a pin passing through the
lower end of the shell Although entirely formed of metal, they are
lighter than wooden ones with their iron bindings, and capable of the
same service.
There is another species of blocks, which are termed " Dead-eyes,"
and are used for tightening or setting up, as it is called. the standing
rigging of ships. It consists merely of a circular block of wood,
with a groove on its circumference, round which the lower end of the shroud, or an iron strap, is fast-
ened three holes passing through the face, (ranged in a triangle,) to receive the laniard or smaller rope,
which forms a species of tackle for tightening the shrouds. There are no sheaves in the dead-eye, but
the edges of the holes are rounded off to prevent cutting the laniard, but this very imperfectly answers
the purpose as from the roughness of the grain of the wood, which is usually elm, and from the stiff-
ness of the rope, the laniard renders with difficulty; and from the great strain to which it is subjected,
it is frequently broken. A very simple and effectual improvement has been made in this respect, by
inserting a half-sheave of lignumvitæ into each of the holes, which causes the laniard to render with
greater facility, and the shroud to be set up in half the usual time. Fig. 250 shows the dead-eye; Fig.
18
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BLOW-PIPE-ANALYSER.
251 a section of the same and Fig. 252 one of the half-sheaves. It will be seen,
from the manner of inserting the half-sheaves, as shown in Fig. 251, that they
cannot fall out, for the more pressure there is on them, the faster they will be.
253.
Fig. 253 represents a block of a peculiar description, intended for form-
ing a kind of rope-road to a stranded ship. When a vessel thus circumstanced
has had a rope thrown over, considerable difficulty has been found in reeving an
ordinary pulley for the conveyance of the crew to the shore. In the figure, it will
be seen that the pulley divides at the hook, or shackle, into two equal parts, so
that it may be instantaneously passed on to a stretched rope, and, by means of a
cord from the ship, persons may pass securely and quickly backwards and for-
wards. The little bar which traverses the opening is fixed at one end by a joint,
and fits into a mortise, as shown; the use of it being to confine the rope to its place,
when any vehicle, or other apparatus, is slung or suspended to it.
251.
250
252.
BLOOD. The principal use of blood in the arts is for making Prussian blue, or sometimes for
clarifying certain liquors. It is also recommended in agriculture, as an excellent manure for fruit-
trees. A mixture of blood with lime makes an exceedingly strong cement; and hence its use in the
preparation of some chemical lutes, the making floors, dc.
BLOOM. A mass of iron after having undergone the first hammering, called bloomary. It requires
many subsequent hammerings or rollings to render it fit for smiths' use.
BLOW-PIPE-ANALYSER. This simple instrument for finding the weight of any very minute
metallic globules without a balance, was invented by (Prof. O. Byrne,) the editor of the present work,
in 1844, and communicated to " THE LONDON CHEMIST," for June in that year.
Dr. Sheridan Muspratt, of Liverpool, has introduced it, in an Appendix to his English translation of
Plattner's excellent work on the Blow-pipe; and it is now much used by European Analysts.
Let A BCD, and A B FG, Fig. 254, be two pieces of very finely polished plate-glass, joined together
at A B, forming with each other a very acute angle.
The figure is distorted, and the necessary mounting omitted, for the purpose of exhibiting the parts
more distinctly. A C and B D represent scales of equal parts, of a greater or less degree of fineness,
according to the exactness required; they may be drawn on paper, and pasted to the glass. X Y is a
cylindrical piece of wire of any convenient length, or of any sort of metal, placed between the plates
of glass, near the top, parallel to A B: the planes are tangent planes to the cylindrical wire. This
wire must have a fixed position while experimenting. The diameter of this cylinder can be calculated
with very great accuracy, by weighing a pound, or a half-pound, of the wire from which it is cut; this
weight divided by the length of X Y will give its weight, and, from knowing the specific gravity of the
metal, the diameter of the wire can be thus accurately determined; this diameter will be the diameter
of the globe n, the greatest possible that can be made out of the cylinder XY. The solidity of this
globe can be also readily ascertained, and would stand in the same position, subtending the same acute
angle, if the cylinder were removed.
Suppose the inch and the ounce to be the units of measure and weight respectively, L the length of
a piece of wire weighing q ounces, from which X Y=1 is supposed to be taken, then the weight
of XY.
Then say as, S L LS the solidity of XY in cubic inches, S being the specific gravity of the
motal, or the numbers of ounces in 1728 (=c) cubic inches:-
area of the circular cross-section of XY.
=3.14159, &c.
»LS = the diameter of this section, or of the globe n, the solidity of which
÷ an expression well adapted to logarithmic computa-
tion, which is independent of the length of XY.
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EXAMPLE-Suppose a piece of copper wire 3765 inches long, to weigh 5 ounces, what is its diameter?
And what is the solidity of the greatest globe that can be taken out of its cross-section 1
Let L = 3765, S = 9008, c = 1728, q =5, and K = 3.14159, dc.
Then log. 4. = 0-6020600
log. q. = 0.6989700
log. c. = 32375437
Sub. log. T. = 9.5028501
Sub. log. L = 74242350
Sub. log. S = 60458716
Reject 30 27-5110304
2) 8-5110304
The diameter of the wire = 0569528 = 27555152
8
42665456
Log. =
1-7189986
Log. 00009672622 = 5.9855442
So that the diameter and solidity of a globe, placed in the position of any wire X Y, can be determined
to any degree of accuracy required. If the part X Y be taken from such a wire as the one given in
the example, the diameter would be 0569528 inches, and the solidity of n, 00009672622 cubic inches.
254.
C
n
X
Y
a
b
c
d
e
g
oh
ok
I
m
B
The solidity of any other globule, a, b, c, or d, &c., suspended between the planes of glass, can be
readily found, from knowing the distance of its centre from the line A B, where the planes meet and
the distance of the axis of the cylinder from the same line. These distances may be measured in a
alant line by the scales A C, BD, and will answer as well as the perpendicular distances between the
axis and centres. If very great accuracy be required, two distances are necessary-the one above,
and the other below the globule: for instance, let us take the globule d, the distance c' the lower limb
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BLOWING-MACHINES.
from A B is 49, according to the design of our woodcut, and the distance of the upper limb is 54; there-
fore its centre may be said to be 49+54 2 515 parts from the line AB. It is convenient, but not
necessary, to have the wire X Y so placed, that the distance of its axis from A B may correspond with
10, 100, 1000, &c., on the scales A C, BD.
Suppose the wire n to be 80 placed that 8' t' reads on the scale A C and BD, referring to the first
figure at 1002, and w' v' to read 998; then 1002 + 998 2 = 1000, the best position for the wire which
keeps the planes apart. Let m' n' be at 645, and p' q' at 643, then the globule may be said to stand at
645-2643-644.
255
Indeed, if the globules were read off all above, or all below, it would answer the
same purpose, observing to keep the lines s' t', m' n', or w' v', p' q', dic., parallel.
s
Then 1000 : 644" :: S : S4; S and S. being the solid contents of n and d respec-
tively.
n
:. 1000' : 644" W : W.; W and W. being the weights of n and d respectively.
Hence W.= 1000000000
The weights and solidities, or volumes of the small globules a, b, c, d, e, f, g, h, i,
&c., supposing them to stand at 947, 895, 763, 644, 602, 533, &c, respectively, will
be in like manner expressed by-
1000000000
And
S₁
1000000000
The co-efficient, { 1000000000 } or similar ones, can be de-
termined with great ease by a table of the cubes of numbers; in fact, they may
be ascertained by addition. If
It is evident, if the weights W1, W,, W,, &c., of a great number of globules, a, b, c, d, &c., of any
sort of metal, be taken together with a very fine balance, and the co-efficient f, determined by a table
of cubes, the weight W, of the globe n, can be determined with the greatest possible accuracy, no matter
what the specific gravity of the globules may be.
Thus, having found the volume and weight of n-and this may be done to any degree of accuracy-
the weight and volume of any other globule or number of globules may be at once determined from-
w
1000000000
S,+S,+S,+S,+dc:=f; or
It may be remarked, that a detached scale of box or ivory will answer the same purpose as the
attached scales A C, BD.
BLOWING-MACHINES. Machines employed for producing a rapid combustion of fuel, by
furnishing a more copious supply of air than can be obtained by the mere draft of the ordinary chin-
neys. Although the common bellows is undoubtedly a blowing-machine, yet the term is generally
restricted in its application to those machines which are employed at large furnaces, as in foundries,
forges, &c. Blowing-machines are constructed of various forms, the great object in all being, that the
blast should be as continuous and uniform as possible. The method of producing such blast by a
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centrifugal force has long been known, but the first blowing-machine on this principle, of which we
have a distinct account, is that invented by Mr. Tyrrell, in 1729. It consists of a number of vanes
or fanners, radiating from a horizontal shaft, and enclosed within a cylindrical box, having two aper-
tures at opposite sides of the cylinder, to one of which is fitted a conical pipe leading to the furnace,
whilst the air enters by the other aperture, and the shaft being turned with great rapidity, a copious and
uniform current of air may be impelled through the conical pipe to the furnace. From the great sim-
plicity and cheapness of these machines, they have recently been coming into more general notice.
Another kind of blowmg-machine, and which is very extensively used for smiths' forges, is the double
bellows. This machine in form resembles an ordinary single bellows, but is divided into two parts by
a middle board, similar to the bottom board, and like it furnished with a valve opening upwards. The
upper and under boards are each loaded with weights, which compress the upper and distend the lower
compartments, and the middle board is supported in a horizontal position upon a frame. The pipe or
nozzle of the bellows communicates with the upper compartment of the bellows only whilst the air is
admitted by the valve in the lower compartment. The action of the machine is as follows: The lower
board being raised by the brake or handle, the air contained in the lower compartment is driven through
the valve in the middle board into the upper compartment, and not escaping from it through the nozzle
as fast as it is forced into it, it elevates the upper board, and thus distends the upper compartment.
Upon the descent of the lower board, the valve in the middle board closes, and the upper board de-
scending by the pressure of the weights upon it, the air beneath it is urged through the nozzle in a con-
tinuous current. During the descent of the lower board, the air enters by the valve in the board, and
fills the lower chamber of the bellows; and upon the rise of the board it is forced into the upper
chamber as before, and thus a continuous blast is maintained. But although continuous, it is not quite
equal, or of a uniform force; for during the up-stroke the air is compressed by a force exceeding that
of the weights on the upper board, since it causes the upper board to ascend; but upon the descent of
the lower board, the air is expelled by the pressure of the weights alone, which, being at all times the
same, the current is then nearly uniform.
Another species of blowing-machine is the water-bellows. The nature of these machines will be
readily understood by the help of the following diagram. The side figure is a vertical section of the
machine. a is the fulcrum of the lever or beam, with
two inverted vessels, b and c, suspended from its ex-
256.
tremities; these vessels are open underneath, but
air-tight above. d and e are two larger vessels,
filled with water to the same level, in which the
vessels b and c rise and fall alternately. g h i is
b
a tube or pipe, which passes through the vessels d
and e, and reaches above the surface of the water;
c
at the extremities are two valves, which respect-
ively open outwards into the inverted vessels, with a
pipe at h open to the atmosphere. k and l are pipes
d
E
passing through the bottom of d and e, and extending
a little above the surface of the water; they are
open at top, and have valves at bottom opening into
the trunk o, to which the pipe is fitted which con-
o
o
ducts the blast to the furnace. An alternating mo-
tion being imparted to the beam by a steam-engine or other first mover, the air passes up the tubes g hi,
and fills each inverted vessel as they are successively drawn up out of the water the descent of the
inverted vessel closes the valves at g and i, and opens those at the bottom of the tubes k and l, through
which the air is driven forward by the trunk o, and thus by the reciprocation of the beam, a continual
blast is maintained through the trunk o and the tuyere of the furnace.
But the most perfect blowing-machines are those in which the blast is produced by the motion of
pistons in a cylinder. The annexed engraving represents a blowing-machine of this description. It
consists of two double-acting force-pumps, placed at right angles to each other, to equalize the draft,
they are driven by a water-wheel of 5-horse power. a is the vertical cylinder; b the horizontal cylin-
257.
e
h,
c
a
g
c
b
der ; cc two connecting rods united to the crank d; e the working-beam f the parallel motion; g the
pipe for conveying the blast to the cupola or furnace h; i a small wheel, running in a groove in a cast-
ron plate j frame supporting the vertical cylinder, between which the lowermost connecting rod, c,
passes. Atkk are placed valves, to admit the air into the vertical cylinder; similar valves are placed
at the ends of the horizontal cylinder into it. The operation is simply this By the revolution of the
crank the air is drawn in at each end alternately of both cylinders. and at the same time it is forced out
at the opposite extremity along the pipe g into the furnace; and the cylinders being placed at right
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BLOWING-MACHINE
angles, one piston will be moving with its greatest velocity whilst the other is moving with its least
velocity, by which means the blast is rendered nearly uniform, and an air-chamber or reservoir rendered
unnecessary. The first cylinders of magnitude used as blowing-machines, were erected by Mr. Smeat-
on, in 1760, at the Carron Iron Works, the cylinders being four in number, 4 feet 6 inches in diameter,
and the piston making a stroke of 4 feet 6 inches in length.
BLOWING-MACHINE, or Air Fan. Description.-Fig. 258 gives an elevation and section of the
apparatus, which is composed of an undershot wheel, and of a box containing it.
D
a
d
d'
274.
273.
266.
0
258.
264.
265.
H
of
269.
O
267.
M
Y
270.
271.
260.
K
I
De,
268.
K
M
H
K
Fy
alo
261.
P
D
o
Pa)
R
x
a
I
263.
259.
e
262.
À
I
The box is supported by a brick wall A, Figs. 258, 259, and 260; a strong cast-iron plate is fixed to
this wall by the tive pins b. The two cheek-pieces B', also of cast-iron, are similar to each other; they
are circular at the part b', b, 6" of their circumference, and have an edge projecting outwards, by which
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BLOW-PIPE.
10$
they are solidly adapted to the plates B by screws. The internal surface of the cheek-pieces must be
level. Their centre has a circular opening Bᵃ, Fig. 262, concentric in this there is a beam to which sup-
porters C of the axle are fixed by wedges; they must be carefully set, in order that the centre of the
axle will be at the centre of the cheek-pieces.
The sides of the box are composed of thin sheet-iron; the cheek-pieces touch it on all the points of
their circumference it must be cylindrical, in order that the wheel may not be impeded in its rotation;
and since it is necessary that the air compressed by the motion of the wheel should find no exit, lead
sheets are nailed between the table and the projection of the cheeks, the sheet-iron being itself closely
adapted by an iron band; pins closely set, strengthen the whole.
The only apertures to the box are at B²; through these it takes in the air; through the lateral open-
ings D, the compressed air is conveyed to the furnace. The axle E, made of wrought-iron, traverses the
box in its breadth, and bears a pulley F which rotates it. The arms G are of wrought-iron, and adapted to
the axle by the two disks H, riveted together; the arms are twisted at g to receive the paddles 1, made
of sheet-iron 0.0984 ft. thick. Their breadth is about equal to the distance of the internal surfaces of
the cheeks, and their length is such, that their extreme circumference is always at a little distance from
the interior surface of the box.
On account of the rapidity of the rotation, the arms G are connected by a circle K of iron riveted to
them.
The wheel makes 1200 revolutions per minute, so that the extremity of the paddles travels 1640 feet
in the same space of time. The air in contact with them receives their speed, and when it attains the
free space D, Fig. 259, it rushes into it, tangentally obeying the impulsion it has received. The air thus
forced has a speed of nearly 3280 feet per minute.
The spout D', which receives the air at its exit from the ventilator, is represented in Figs. 271 and
272, in transverse and horizontal section. This principal channel distributes the air through secondary
pipes d, by which it is conveyed to the furnaces; the quantity of air is regulated by registers d¹. The
orifices have a diameter of from 0.00328 feet to 0.008 feet, according to the size of the piece to be
wrought. Fourteen furnaces can be ventilated by this apparatus: a power of four horses is estimated
sufficient to set it in motion.
Fig. 258.-An external view of the ventilator fixed on the brick wall.
Fig. 259.-Longitudinal section.
Fig. 260.-Transverse section through the axle of the wheel
Fig. 261.-Plan of the cast-iron plate B.
Figs. 262 and 263.-Elevation and horizontal section of one of the cheek-pieces B'.
Figs. 264 and 265.-Details of the supporter C.
Fig. 266.-The oil reservoir, with the siphon.
Figs. 267 and 268.-Projection of the wheel.
Figs. 269 and 270-The disk H.
Fig. 271.-The axle E, of wrought-iron.
Fig. 272.-Projection of the pulley F.
Fig. 273.-Main channel D', and one of the lateral pipes d distributing the air.
Fig. 274.-A horizontal section of one of these pipes, and of the register d¹, by which the quantity of
air forced out is regulated.*
BLOWING OFF. Amount of heat lost in See DETAILS OF ENGINES.
BLOW-OFF COCKS AND PIPES. See DETAILS OF ENGINES.
BLOW-PIPE An instrument for exciting intense combustion upon a small scale; it is extensively
used in many branches of the arts, and also in philosophical experiments upon metallic substances. In
its simplest form it is merely a conical brass tube, curved at the small end, in which is a very minute
aperture; and a stream of air being urged through it by the mouth against the flame of a lamp or
candle, a heat equal to that of the most violent furnaces may be produced. The body intended to be
operated upon should not exceed the size of a peppercorn, and should be supported upon a piece of
well-burned, close-grained charcoal, unless it be of such nature as to sink into the pores of the charcoal,
or to have its properties affected by its inflammable quality. Such bodies may be placed in a small
spoon made of pure gold, silver, or platinum. Many advantages may be derived from the use of this
simple and valuable instrument. It is portable; the most expensive materials, and the minutest speci-
mens of bodies, may be used in the experiments; and the whole process is under the eye of the
observer. In the blow-pipes used by enamellers, glass-blowers, and others, the current of air is main-
tained by a small pair of double bellows.
Early in the present century, Dr. Hare, of Philadelphia, made a most important improvement in
the blow-pipe, by substituting for the flame of a lamp that arising from a mingled current of oxygen
and hydrogen, of which we shall treat presently.
The Hydrostatic Blow-pipe consists of a cask, divided by a horizontal diaphragm into two parts DD.
From the upper apartment, a pipe of about 3 inches diameter (its axis coincident with that of the cask)
descends, until within about 6 inches of the bottom. On this is fastened by screws, a hollow
cylinder of wood B B, externally 12 inches in diameter, and internally 8 inches. Around the
rim of this cylinder a piece of leather is nailed, 80 as to be air-tight. On one side a small groove
In a blast apparatus employed at the Cyfartha Works, moved by a 90-horse steam-power, the piston-rod of the
blowing-cylinder is connected by 8 parallelogram mechanism with the opposite end of the working-beam of the steam-
engine. The cylinder is 9 feet 4 inches diameter, and 8 feet 4 inches high. The piston has a stroke 8 feet long, and #
rises 13 times In the minute. By calculating the sum of the spaces percurred by the piston in a minute, and supposing
that the volume of the air expelled is equal to only 98 per cent. of that sum, which must be admitted to hold with ma-
chines executed with 80 much precision, we find that 12,583 cubic feet of air are propelled every minute. Hence a herse-
power applied to blowing-machines of this nature gives, on an average, 137 cubic feet of air per minute. The pressure on
the air, as it issues, rarely exceeds two pounds on the square inch in the Welsh works.
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BLOW-PIPE.
is made in the upper surface of the block, 80 that
275.
a lateral passage may be left when nailed on each
side of the groove. This lateral passage com-
municates with a hole bored vertically into the
wood by a centre-bit; and a small strip of leather
being extended 80 as to cover this hole, is made,
with the addition of some disks of metal, to con-
stitute a valve opening upwards. In the bottom
of the cask there is another valve opening up-
wards. A piston-rod, passing perpendicularly
G
through the pipe from the handle H, is fastened
near its lower extremity to a hemispherical mass
of lead L The portion of the rod beyond this
proceeds through the centre of the leather which
covers the cavity of the wooden cylinder; also
through another mass of lead like the first, which,
being forced up by a screw and nut, subjects the
leather between it and the upper leaden hemis-
D
phere to a pres ure sufficient to render the junc-
D
ture air-tight. From the partition, an eduction-
pipe E is carried under the table, where it is
fastened by means of a screw to a cock which
carries a blow-pipe, so attached by a small swivel-
joint as to be adjusted in any required direction.
A suction-pipe passes from the opening covered by
L
the lower valve, under the bottom of the cask, and
rises vertically close to it on the outside, terminating
c
B
in a union-joint for the attachment of any flexible
tube which may be necessary. The apparatus being
thus arranged, and the cask supplied with water
until the partition is covered to about the depth of 2 inches, if the piston be lifted, the leather will be
bulged up, and will remove in some degree the atmospheric pressure from the cavity beneath it; con-
sequently the air must enter through the lower cavity to restore the equilibrium. When the piston is
depressed, the leather being bulged in an opposite direction, the cavity beneath it is diminished, and
the air being thus compressed, forces its way through the lateral valve into the lower compartment of
the cask, which compartment being previously full of water, a portion of the fluid is pressed up through
the pipe into the upper apartment. The same result ensues each time that the stroke is repeated, so
that the lower compartment soon becomes filled with air, which is retained by the cock until its dis-
charge by the blow-pipe is necessary. Dr. Hare, in his oxy-hydrogen blow-pipe, did not mix the gases
in his gas reservoir, but supported the flame of the hydrogen by a current of oxygen issuing from
different jets. Subsequently, it was found that the heat produced was materially affected by the
proportions in which the gases were mixed, and that the greatest intensity of heat was obtained by
two volumes of hydrogen united with one of oxygen; and various attempts were made to mix and
burn the gases in their due proportion, but with little success, until the important improvement effected
in the instrument by Dr. Clarke, Professor at Cambridge. This improvement consisted in first mixing
the gases in a bladder, in the exact proportions to form water, and afterwards condensing them in a
strong iron chest, by means of a condensing syringe. To an opening at the end of this chest he attached
a great number of layers of fine wire gauze, through which the mixed gases were driven by their
elastic force into a small tube, at the end of which they were inflamed. By this arrangement he ob-
tained a much greater heat than had been effected by Dr. Hare's invention, and was enabled to make
a great number of experiments highly interesting to science. Unfortunately, however, for the general
adoption of his plan, it was soon found that his instrument was unsafe to use; that the wire gauze
would not prevent the explosion of the gases, that in several cases, when used by the most experienced
and cautious operators, the instruments were burst. The explosions were tremendous, and resembled
the bursting of a bomb, the fragments of the iron chest being scattered with great force in all direc-
tions. After trying various plans to render the invention safe, the Doctor, as a protection, had the iron
chest placed behind a brick wall at the back of the operator, the gases being conveyed through a tube
passing through the wall. In this state the instrument remained, until Mr. Goldsworthy Gurney applied
himself to its improvement, and after numerous experiments, which are highly interesting, and are
fully detailed in his published lectures, he succeeded in producing an instrument unattended with the
elightest danger in its use, and admirably adapted both for scientific investigation, and for various
operations in the arts. The annexed engraving is a representation of the instrument. A is the safety-
chamber; B a water-trough, through which the gas is made to pass from the gasometer D by the cock
C, through a tube which reaches to the bottom of the water-trough; E is a cock fitted into the neck of
the same, from which it is thrown out should an explosion take place on the surface of the water. F
is a gage, to indicate the necessary height of the column of water in the trough. G is a transferring
bladder, which is made to screw and unscrew to and from the stop-cock H, for the purpose of supply
ing the gasometer with gases, which may be charged and recharged at pleasure, by an assistant,
during its action, 80 as to keep up the most intense flame for any length of time. A valve is placed
between the gasometer and the transferring bladder, which prevents the return of the gas. II is a
light wooden or stiff pasteboard cap, which combines sufficient strength with great lightness, so that in
case an explosion of the gasometer should happen, it is merely thrown a short height into the air, by
the force breaking the strings which connect the cap to the press-board. To these strings are attached
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BLOW-PIPE.
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276.
I
D
o
L
Q
=
H
N
small wires which pass through the table of the instrument, as at L, into the press-board below, where
they are secured; this press-board is kept in a horizontal position by the stand, so that when the re-
quisite pressure is given to it, the cap 1 1 is brought to bear equally on the gasometer D. The gas-
ometer bladder (or silk bag) is tied to a piece of bladder, which screws into a long tube laid into and
across the table, which permits it to be unscrewed at pleasure from the body of the instrument, and
immersed in water when it requires softening, affording also the means of fixing on another bladder, if
any accident should render it necessary. The stop-cock of the charging bladder G is fixed to one end
of the tube just described, and the stop-cock of the water-trough on the other end. To operate with
this instrument, pressure by the hand is applied to the press-board, which draws down the cap I I on
the gasometer D, and forces the gas which it contains through the stop-cock C, and through the water-
tube and safety-chamber A, to the jet at the end, where it is burned. When the pressure on the press-
board is too slight, or when the hand is taken off, the flame returns into the safety-chainber, and is
extinguished. When it is required to suspend the operation, the hand need only be taken off the
pressing-board; the water in the trough acts as a self acting valve in preventing the escape of gas
from the instrument, and saves the necessity of turning the stop-cock. A silk tube is attached to the
end of the tube before described, in the water-trough, which prevents the splashing of the water,
sometimes occasioned by unskilful management. We omitted to state that the safety-chamber A is
filled with numerous disks of very fine wire gauze closely packed, and should the flame be driven
in, which will sometimes happen, it will not enter the bag or reservoir D, but will explode above
the surface of the water in the chamber B, merely driving out the cork. An improvement has, how-
ever, been since introduced in the construction of the safety-chamber, by Mr. Wilkinson, by which the
retrograde motion of the flame appears to be effectually prevented. and a much larger jet may be
employed than heretofore with perfect safety. This improvement consists in filling the chamber A
with alternate layers of wire gauze and of asbestos, previously beaten with a mallet, and pulled out
to resemble floss silk. Mr. Wilkinson received from the Society of Arts a silver medal for his com-
munication on the subject, and we understand that Mr. Hemming has recently made some further im-
provements in the construction of the instrument. We must here advert to the wonderful effects
produced by the oxy-hydrogen blow-pipe, which almost instantaneously reduces the hardest and most
refractory substances. Gun-flints are instantly fused by it, and formed into a transparent glass; china
melts into a perfect crystal. All kinds of porcelain are readily fused, previously assuming a beautiful
crystallized appearance. Rock crystal is quickly melted, giving out a beautiful light. Emerald, sap-
phire, topaz, and all the other precious stones, melt before it into transparent glassy substances. Barytes,
strontian, lime, and alumina, exhibit very striking and beautiful phenomena. Magnesia fuses into hard
granular particles, which will scratch glass. The metals, even platina, are all quickly fused by it: and
all descriptions of stones, slates, and minerals, are melted, sublimed, or volatilized, by its all-subduing
power.
BLOW-PIPE. DR. HARE'S HYDRO-OXYGEN; On certain improvements in the Construction and Sup-
ply of the Hydro-oxygen Blow-p.,e, by which Rhodium, Iridium, or the Osmiuret of Iridium, also Plati-
num in the large way, have been fused. By Robert Hare, M. D,, Professor of Chemistry in the University
of Pennsylvania.
While a pupil of my predecessor, Dr. Woodhouse, in the year 1801, having observed that a jet of
hydrogen when inflamed in atmospheric air, of which only one-fifth is oxygen, was productive of a heat
of pre-eminent intensity, I was led to infer that in combining with pure oxygen, the gas in question
ought to produce a temperature at least five times as great. This led to the contrivance of two modes
of producing a jet consisting of a mixture of hydrogen with oxygen. Agreeably to one mode, the
gaseous currents, meeting like the branches of a river, were made analogously to form a common
stream. This object was accomplished by means of perforations drilled in a conical frustrum of pure
silver, so as to converge until met by another shorter perforation, commencing at the opposite surface,
and so extended as to join them at the point of their meeting. The other mode was that of causing one
tube to be within another, so as to be concen'ric, the outer tube being a little the longer of the two;
the latter being employed for hydrogen, the former for oxygen.
In the year 1814, this last-men ioned mode was improved, so as to have the means of securing, by
adjusting screws, the concentricity of the tubes, and varying the distance of the orifice of efflux of the
inner tube from that of the other.
The constructions employed in 1801, were described and published in a pamphlet, and afterwards
14
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BLOW-PIPE.
republished m Tillock's Philosophical Magazine, vol. xiv., and in Annals de Chymie, vol. xiv. At the
same time an account was given of the fusion of pure lime and magnesia, and of the fusion of platinum.
Subsequently, in a paper published in the Transactions of the American Philosophical Society, it was
mentioned that I had volatilized platinum.
About the year 1811, Professor Silliman, in a memoir read before the Connecticut Academy of
Sciences, gave an account of a series of experiments, in which the experiments which I had performed
were repeated, and many additional fusions made. I had adverted to the intensity of the light pro-
duced during the exposure of lime to the flame. Alluding to the heat and light, my words were, the
eyes could not sustain the one, nor the most refractory substances resist the other." The intensity of
the light was still more insisted upon by Silliman.
My experiments were also repeated by Mr. Rubens Peale, during many successive years, at the
Philadelphia Museum, for the amusement of visiters.
About the year 1813-14, it was ascertained, at the laboratory of Dr. Parrish, that a bladder being
supplied with a mixture of hydrogen and oxygen, in due proportion, and punctured by a pin, while
subjected to compression, on igniting the resulting jet, the gas within the bladder did not explode. Of
course, a burning jet of flame thus created was found competent to produce, while it lasted, the same
effect as when otherwise generated by the same gaseous mixture.
Soon after this result was obtained, Sir Humphrey Davy discovered, that if a lamp flame be com-
pletely surrounded by a gauze of fine wire, it may be introduced into an inflammable gaseous mixture
without causing it to explode. This was ascribed to the refrigerating influence of the metal, keeping
the gaseous mixture below the temperature requisite for inflammation. Hence it was inferred, that if
a mixture of hydrogen and oxygen, while condensed within a suitable receiver, was allowed to escape
through a capillary metallic tube, 80 as to form a jet, this might be made to burn without communica-
ting ignition to the portion remaining in the receiver.
By means of an apparatus contrived agreeably to this idea, Dr. Clark, of Cambridge, England, re-
peated the experiments, made many years before by Silliman and myself, without any other reference
to ours, than such as was of a nature to do injustice. An exposition of the invalidity of Dr. Clark's
pretensions to originality was made in Silliman's Journal for 1820, vol. ii., and in Tillock's Philosophi-
cal Magazine for 1821, vol. lvii.
The light produced by the hydro-oxygen flame with lime having been observed by Lieutenant Drum-
mond, of the British Navy, was ingeniously proposed by him as the means of illumination in light-
houses, and has been, in consequence, subsequently used as a substitute for the solar rays, in an instru-
ment known as the hydro-oxygen microscope, which is a modification of that which has been called the
solar microscope. The name of Drummond light has consequently been given to a mode of illumination,
which I originally produced as above stated.
The instrument which was used by Professor Silliman and by Rubens Peale, was that above described
as having two perforations meeting in one. In this form it was, I believe, employed by Dr. Hope, of
Edinburgh, and Dr. Thompson, of Glasgow, who both treated it as my contrivance, anteriorly to the
publication of Dr. Clark's memoir.
The other form, consisting of two concentric pipes, was modified by a Mr. Mangham, with the view
of producing a lime light for the microscope above alluded to. When I saw Mr. Mangham at the
Adelaide gallery in 1836, he treated this instrument as mine, in another form. I was surprised after
wards to learn that he had obtained a premium for this modification from the British Society for the
Encouragement of Arts, without any allusion to the original inventor.
After my return from Europe in 1836, I was very much in want of a piece of platinum of a certain
weight, while many more scraps than were adequate to form such a piece were in my possession.
This induced new efforts to extend the power of my blow-pipe; and after many experiments, I suc-
ceeded so as to fuse twenty-eight ounces of platinum into one mass.
Although small lumps of platinum had been fused by many operators, with the hydro-oxygen blow-
pipe, as well as myself, it had not, up to the year 1837, been found sufficiently competent to enable
artists to resort to this process. I am informed by Mr. Saxton, that some efforts which were made
while he was in London were 80 little successful, that the project was abandoned. There was an
impression that the metal was rendered less malleable when fused upon charcoal, as in the experiments
alluded to. This is contradicted by my experiments, agreeably to which fused platinum is as malleable
as the best specimens obtained by the Wollaston process, and is less liable to flake. The celebrated
Dr. Ure, on seeing the platinum in the forms of wire, of leaf, and plate, said that there was no one in
Europe who could fuse platinum in such masses. He also alleged that it had been found so difficult to
weld platinum, that no resort was had to that process. In this I concur, having had the welding tried
by a skilful smith, both with a forge heat, and with a heat given by the hydro-oxygen blow-pipe. An
incorporation of two ingots was effected on their being hammered together, when heated nearly to
fusion; but on hammering the resulting mass cold, a separation took place along the joint by which the
ingots were united.
The difficulty seems to arise from the rapidity with which the platinum becomes refrigerated. It
seems to have a less capacity for heat than iron, and, not burning in the air as iron does, has not the
benefit of the heat acquired by iron from its own combustion with atmospheric oxygen.
Latterly, by means of the instrument and process which it is my object here to describe, I have been
enabled to obtain malleable platinum from the ore directly, by the continued application of the flame.
From some specimens of platinum I have procured as much as ninety per cent. of malleable metal
The malleability is not inferior to that of the best specimens obtained, by reducing it to the state of
sponge, through the agency of aqua regia and sal ammoniac. There is, however, a greater liability to
tarnish, arising, probably, from the presence of a minute portion of palladium.
Of the fusion of iridium and rhodium, I have already given an account in the Bulletin of the Society,
which was subsequently embodied in an article prepared for Silliman's Journal for October last, 1846.
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BLOW-PIPE.
107
It remains now to give an account of the apparatus employed in the fusion of platina on a large
scale.
Fig. 277 represents the association of fifteen jet-pipes of platina with one large pipe, D B, at their
upper ends, 80 that their bores communicate, by means of an appropriate brass casting, with that of the
large pipe, the joints secured by hard solder. Their lower extremities are made to protrude about half
an inch from a box A, of cast brass, their junctures, with the appropriate perforations severally made
for them, being secured by silver solder. They come out obliquely in a line along one corner of the
box, an interval of about a quarter of an inch alternating with each orifice. By means of flanges, the
brass box is secured to a conical frustum of copper, Fig. 278, 80 as to form the bottom thereof, while
the pipe, extending above the copper case, is screwed to a hollow cylinder of brass, A, Fig. 279, pro-
vided with two nozzles and gallows screws gg for the attachment of appropriate hollow knobs, to which
pipes are soldered, proceeding from the reservoirs of oxygen and hydrogen. Cocks are interposed by
which to regulate the emission of the gases in due proportion.
277.
D
279.
278.
A
g
B
g
D
B
c
E
280.
In connecting the pipes conveying the gases with the brass cylinder, A, Fig. 279, care should be
taken to attach that conveying oxygen to the upper nozzle, while the other, conveying hydrogen, should
be attached to the lower nozzle; since, by these means, their great difference in density tends to pro-
mote admixture, which, evidently, it must be advantageous to effect.
The object of surrounding the jet-pipes with water, by means of the copper box,* is to secure them
against being heated to such a degree as to cause the flame to retrocede and burn within them, 80 as
finally to explode within the cylinder, A, gg, Fig. 279. It is preferable to add ice or snow to the
water, in order to prevent undue heat.
Fig. 280 represents a moveable platform, A, of cast-iron, wholly supported upon the point of the iron
lever D B, which is curved towards the extremity under the platform, 80 as to point upwards, and to
enter a small central conical cavity made for its reception. The lever is supported by a universal joint
upon the fulcrum C, so that by means of the sliding-weight at one end, the platform and its appurte-
nances are counterpoised at the other. The platform is kept in a horizontal position by the cannon-
ball, supported in a sort of iron stirrup terminating in a ring, in which the ball is placed. Upon the
platform is situated an iron pan with a handle, holding the brick, on a cavity in which, as already
. Since the engraving was made, I have preferred to use water-tight boxes, with gallows screws and nozzles. situated
one near the bottom on one side, the other on the opposite side near the top. By means of the lower nozzle, a pipe is
attached, communicating with a head of cold water, the other being 80 situated as to carry the water into a waste pipe, or
large tub: a circulation may be kept up during the whole time that the operation is going on.
As a support, a brick of kaolin is used, having an oblong elipeoidal depression on the upper face for the reception of the
metal to be fused.
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108
BLOW-PIPE.
mentioned, the metal is supported. The apparatus being duly prepared, and connected with the supply
pipes, the hydrogen is first allowed to escape, and then the oxygen, until the ignition has attained
apparently a maximum. The accomplishment of this object may, of course, require the adjustment of
either cock several times; especially where there is any decline in the pressure either of the one or the
other gas in its appropriate reservoir.
By means of the handles of the lever and of the pan, the operator is enabled to bring the metal into
the position most favorable for the influence of the heat, while his hands and face are sufficiently re-
mote to render the process supportable. In fusing any quantity, not being more than four ounces,
the platform may be dispensed with, the handle of the pan being held in one hand of the operator,
while by the other the cocks may be adjusted.
When the blow-pipe of fifteen jets, or any larger, may be employed, and the platform is necessarily
resorted to, the cocks must be adjusted by an assistant.
Fig. 281 represents a cask made of boiler-iron, three-sixteenths of an inch thick, so as to resist an
enormous pressure. The joints are secured by riveting, as in constructing high-pressure boilers.
282.
H
281.
B
M
HH
L
E
A
N
T
D
C
E
F
This cask communicates with the hydrant-pipes, so called, by which our city is supplied with water,
of which the pressure varies from a half to more than two atmospheres, say from seven to thirty
pounds per square inch, according to the number and bore of the cocks from which the water may be
flowing at the time, for the consumption of the community. Hence, experiments, while using this
head, are best made towards bedtime, or between that time and sunrise. The vessel is filled with
water by opening a cock F on one side of the pipe C, and allowing the air to escape through the
valve-cocks B. Being thus supplied, the cock F closed, and a communication with a bell-glass, into
which oxygen is proceeding from a generating apparatus, being made by means of a flexible leaden tube,
on opening the valve-cock B and the cock E the water will run out, and be replaced by gas from the
bell. This process being continued till the iron cask is sufficiently supplied with gas, the cock E must
be shut. Whenever the gas is wanted for the supply of the blow-pipe, it is only necessary to establish
я communication between the valve-cock B and the upper gallows-screw, Fig. 279, of the cylinder A, and
to open the cock F 80 as to admit the water to press upon the gas, the efflux being regulated by B, or
preferably by a cock of the ordinary construction, one of which kind should be interposed at a con-
venient position between the valve-cock B and cylinder A.
T represents a glass tube, which, by due communication with the interior, shows the height of the
water. and consequently the quantity of gas in the vessel.
G H represents a gaging apparatus, consisting of a cast-iron flask, of about a half a pint in con-
tent, and a glass tube of about a quarter of an inch in bore, which should be at least five feet in height.
The tube is secured air-tight into the neck of the flask, so as to reach nearly to the bottom within.
The flask is nearly full of mercury. Under these circumstances, when a communication is made, by a
leaden pipe between the cavity of the flask and that of the reservoir, an equilibrium of pressure re-
sulting, the extent of the pressure is indicated by the rise of the mercury in the tube.
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BLOW-PIPE.
109
In order to generate hydrogen for the supply of a reservoir like that represented by the preceding
figure, I have employed the vessel represented by Fig. 282. This vessel, by means of a suitable aperture,
susceptible of being closed by a screw-plug, is half filled with diluted sulphuric acid. Being furnished
with a tray of sheet copper D, punctured like a coal-sieve, and supported by a copper sliding-rod E,
strips of zinc are introduced in quantity equal to the capacity of the tray. The sliding-rod passes
through a stuffing-box F, at top of the reservoir, so that the operator may, by lowering or raising the
tray, regulate or suspend the reaction between the zinc and its solvent, accordingly as the supply of
hydrogen is to be produced, suspended, increased, or diminished.
The communication with the reservoir is opened and regulated by means of the cock P, furnished
with a gallows-screw G for the attachment of a leaden pipe, as above described, in the process for
supplying the reservoir with oxygen.
Another apparatus for producing a supply of hydrogen, is represented in Fig. 000. It consists of two
283.
M
L
H
K
c
SE
3
B
C
N
E
c
P
ci2
D
A.
o
similar vessels of boiler-iron, each capable of holding forty gallons. They are lined internally with
copper, being situated upon a wooden frame, 80 that the bottom of one is two-thirds as high as the top
of the other. The upper portion of these vessels communicate by a leaden pipe B, of about half an
inch bore, furnished with a cock, while the lower portions communicate by another leaden pipe of a
bore of 11 inches.
The upper vessel is surmounted by a globular copper vessel, of about twelve inches in diameter,
which, from its construction, renders it possible to introduce an additional supply of concentrated acid
while the apparatus is in operation, without reducing the pressure within the reservoir, by permitting
the excess above the pressure of the atmosphere to escape. This object is accomplished as follows :-
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BOBBINET MACHINERY.
The valve at the end of the rod, attached to the lever L, being kept shut by the catch M, the screw-
plug H removed, the acid is introduced through the aperture thus opened. In the next place, the
plug being replaced, and the valve depressed by means of the lever and rod, 80 as no longer to
close the opening, which it had occupied, the acid descends from the chamber into the cavity of the
vessel beneath it. The valve is of course restored to its previous position as soon as the acid has
effected its descen⁴.
The lowermost vessel is furnished with a perforated copper tray, supported by a copper sliding-rod,
in a way quite analogous to that already described in the case of the copper reservoir. It is also sup-
plied with zinc and its solvent in like manner, being made half full of the diluted sulphuric acid. Of
course, on contact being produced between the zinc and its solvent, the generation of hydrogen will
take place. So long as the communication between the upper portions of the two vessels is open, the
gas will extend itself into both, occupying the whole of the upper vessel, and that half of the lower
one which is unoccupied by the liquid. But if, in this way, the pressure reaches to two atmospheres,
as indicated by the gage, on shutting the communication through the pipe B, the pressure in the in-
ferior vessel will augment, that in the superior vessel remaining as before, but the liquid will conse-
quently begin to pass out of the inferior vessel through the pipe A, and thus may lessen the contact
between the acid and zinc, and finally suspend it altogether. Meanwhile the gas in the upper vessel
being condensed to nearly half its previous bulk, the pressure will be nearly four atmospheres. It
will, in fact, always be nearly double that which existed before the pipe B was closed.
In order that nearly the whole of the acid shall be expelled from the inferior vessel, the tray must be
depressed till it touches the bottom of that vessel.
The pressure being four atmospheres at commencement, as soon as, by means of a pipe attached to
the valve-cock N, an escape of gas is allowed, the acid is forced again upon the zinc, and thus prevents
a decline of pressure to any extent sufficiently to interfere with the process.
The gases may be used from a receiver in which they exist, in due proportion, safely by the following
means. Two safety-tubes are to be made, not by Hemming's process exactly, but as follows :-A cop-
per tube, silver soldered, of which the metal is about the eighth of an inch in thickness, is stuffed
with the finest copper wire, great care being taken to have the filaments straight and parallel. The
tube is then to be subjected to the wire-drawing apparatus, so as to compress the tube on its contents
until the draught becomes so hard, as that it cannot be pushed farther without annealing. The stuffed
tube thus made is to be cut into segments, in lengths about equal to the diameter, by a fine saw. The
surfaces of the sections are to be filed gently with a smooth file. By these means, they appear to the
naked eye like the superfices of a solid metallic cylinder. Brass caps being fitted on these sections,
they are to be interposed by soldering, at the distance of a foot or more, into the pipe for supplying
the jet. Under these circumstances, the posterior section, becoming hot, may allow the frame to
retrocede; but the anterior section being beyond the reach of any possible combustion, and remaining
cold, will not allow of the retrocession; and as soon as the flame passes the first section, the operator,
being warned, will of course close the cock, and subject the posterior section to refrigeration before
proceeding again.
But this plan of operating may be rendered still more secure by interposing a mercury bottle, or other
suitable iron vessel, half full of oil of turpentine, between the reservoir and safety-tubes, as in the
arrangement of a Woulfe's bottle. A leaden pipe proceeding from the reservoir is, by a gallows-screw,
attached to an iron tube which descends into the bottle, 80 as that its orifice may be near the bottom.
The leaden pipe communicating through the safety-tubes with the jet-pipe, is attached to the neck of
the bottle. Thus the gaseous mixture has to bubble through the oil of turpentine in order to proceed
through the safety-tubes to the jet-pipe. If, while this process is going on, the flame should, by
retrocession, reach the cavity of the bottle, exploding in contact with the turpentine, a compound is
formed, which is, per se, inexplosive from the excess of carbonaceous matter. Meanwhile the shock,
acting on the surface of the oil, drives it into the bore of the iron tube, and thus, both by its chemical and
mechanical influence, renders it utterly impossible that the flame should reach the cavity of the reservoir.
BOBBINET MACHINERY, is the name of machines which are intended for manufacturing a
peculiar net-like texture, whose constructure is inferred from that of the pillow-made or bo 'e-lace, and
which, in its most simple intertwisting. is known by the name of plain bobbinet and quillings. The
simple intertwisting of the plain bobbinet has been altered in various manners, and thus have been
produced new kinds of texture, partly very different in appearance from that of the plain bobbinet
and in recent time furnishing very fine fancy articles, much in demand. They are termed figured
bobbinet in the following description, which treats chiefly of the most common and most recent systems
of bobbinet machines.
The machines for manufacturing quillings, and which are known by the term stripe-machines, work
quillings or edgings from to to 4 and 6 inches in breadth, and of considerable length. A great many
edgings, connected with and by the side of each other, thus forming one broad piece, are worked
simultaneously, and are subsequently separated. As the quillings are, as it were, to be edged at both
borders, for the sake of fastness and durability, this edging and intertwisting of the several quillings
require particular contrivances in the machines, which thus, according to the different systems applied
to them, are more or less complicated.
Those for manufacturing the figured bobbinet are in general narrow; that is to say, there can be
worked only pieces of inconsiderable breadth by them.
This is owing partly to the circumstance, that older machines, originally intended for manufacturing
pieces six or eight quarters of a yard wide, have been arranged for figured bobbinet, to make them
still fit for use in any way and partly to the fact that the making of figured bobbinet is by far more
difficult than that of plain bobbinet, and that it requires the most eager attention and skilfulness of the
operative. To the latter it would be almost impossible to overlook broad pieces of this kind, or the
work would go on so slowly that such an arrangement could be of no great avail.
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BOBBINET MACHINERY.
111
Alphabetical Survey and Explanation of the Letters in the Figs. 284 to 394.
A, right side-frame, Figs. 285 and 286.
A1, left side-frame, Figs. 284, 286, and 287.
B, fore front-frame, Figs. 284, 303, 317.
B1, back front-frame, Figs. 284, 303, 317.
C, joist joining the uppermost parts of the side-frames, Fig. 286.
C, pillars screwed on C, and bearing the sockets of the lace-beam A, Fig. 286.
D, rounded iron bars across which the texture passes on its way to the lace-beam, Fig. 286.
D₁,
D2,
cross-beams at the right and left sides of the frame, Figs. 284 and 285.
E, front pusher-bar, Figs. 284, 288, and 289.
E₁, back pusher-ba Figs. 284, 288, and 289.
F, a kind of reed composed of perforated brasses for the warp-threads, Figs. 284 and 286.
F1. steel springs of the hold-fast contrivance, Fig. 357.
(+, warp-beam, Fig. 284.
G,, } lever-arms of the point-bars, Figs. 284, 285, 288, and 289.
G1,
H, lever bearing the weight-stone R, Figs. 284, 286, and 287.
H,, lever moving the front point-bar, Fig. 287.
H2, lever moving the back point-bar, Figs. 287, 288, and 289.
I, cradle-arms, Figs. 284, 285, and 286.
I,, cradle-pieces, Figs. 284, 285, and 286.
K, front bolt-bar, Figs. 286, 288, 289, 300, and 303.
K., back bolt-bar, Figs. 287, 288, 289, and 303.
L, front comb, Figs. 284, 288, and 289.
L₁, back comb, Figs. 284, 288, and 289.
M, front point-bar, Figs. 284, 285, 288, 289.
N, back point-bar, Figs. 284, 285, 288, and 289.
N, crowbar of the front point-bar, Figs. 286 and 287.
N2, crowbar of the back point-bar, Figs. 288 and 289.
o, socket-frame in the midst of the machine. 1 Both are fastened to B and Bt, and bear the sockets
P, socket-frame at the side of the machine. 1 of the lockers, Figs. 315 and 317.
P1, forked bars for both point-bars, Figs. 287, 288. and 289.
Q, weight-stone for the tension of the warp, Figs. 284, 285, 286, and 287.
Q1, lifting-thumb acting on the forked bar P1, Figs. 288 and 289.
R, grooved disks for the cords or strings S, Fig. 286.
R1, large rowels, Fig. 284.
Rr. shell-wheel of the front point-bar, Fig. 286.
Rn, shell-wheel of the back point-bar, Figs. 286, 288, and 289.
8, cords or strings for the tension of the warp, Figs. 284, 285, 286, and 287.
S1, support of the front point-bar, Fig. 287.
S, support of the back point-bar, Figs. 287, 288, and 289.
T.
T,,
shafts to which the lever-arms G₁ and G₂ are fastened, Figs. 284, 288, and 289.
U, large heart-shaped disk to bring about the swinging movement of the pusher-bars, Figs. 284, 288,
289, and 290.
Un similar disk in Figs. 358 and 859.
V. great spur-wheel with 48 cogs at the principal axis W, Figs. 285 and 286.
W, principal axis of the machine, Figs. 284, 286, 288, and 289.
W', driving axis of the machinery for the thong-disk Y, Figs. 284, 285, and 287.
X, dented wheel at the axis W₁, with 36 cogs, Fig. 285.
Y, thong-disk at the axis W1, Fig. 286.
Y1, thong of the disk Y, Fig. 286.
Z, the lace-beam, Fig. 284.
a, front guide-bar, Figs. 284, 331, 332, 303, 317, &c
a,, adjusting screw for the lateral movement of the front guide-bar, Figs. 331, 332, and 333.
a, adjusting screw for the lateral movement of the back guide-bar, Fig. 333.
b, back guide-bar, Figs. 284, 303, 815, 317, and 333.
b1,
by
} curved stays through which the adjusting screws a and a₂ pass, Figs. 331 and 338.
bn common pivot of the levers H and H2 and of the crowbar N and N2 Figs. 287, 288, and 289.
c, front series of guides, Fig. 284.
C1, projecting bolt, through which the supporting screws d and d₂ pass, Figs. 331 and 833.
cm cm } adjusting screws of the levers H₁ and H₁, Fig. 287.
d, back series of guides, Fig. 284.
d₁, d, } supporting screws of the guide-bars, Figs. 331, 833.
e, middle stay of the bolt-bars. Figs. 300, 301, 302.
f, warp-threads, Figs. 284, 335, 336. and 360.
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BOBBINET MACHINERY.
f1, steel springs for pushing back the guide-bars, Figs. 285, 295.
f2, pivots on which the point-bars turn. Figs. 285, 288, 289.
g, socket-irons of the warp-beam, Fig. 284.
I₁,
Is
} lever-bars for the lockers, Figs. 285, 288, and 289.
4, lever-arm at the midst of the axis m, Figs. 358 and 359.
k₁,
lever-arms at the ends of the axis w, Figs. 358, 359, and 284, 285, 288, 289.
h₂,
i, pivot of the lever-bars I₁ and In Figs. 284, 285, 288, 289.
k;
k₁,
weft-threads, Fig. 360.
k₂, curved arms, to which the pivots f2 of the point-bars are fixed, Figs. 285, 288, 289.
1, front carriage-line, Figs. 284, 288. 289.
l₁, back carriage-line, Figs. 284, 288, 289.
l₂, sockets of the shafts T and T1, Firs. 285, 286.
l₃, sockets of the shafts w in Figs. 358, 359.
m,
drawer-bars of the lever-arms h₁ and hr Figs. 358, 359, and 284, 285, 286, 288.
m₁,
m₂, adjusting screw for the lateral movement of the front comb, Figs. 286, 300, 301.
mr adjusting screw for fixing the back comb, Figs. 286, 288, 300, 301.
n, point-pieces, Figs. 284, 286, 288, 289.
n.,
split sockets of the guide-bars, Figs. 304, 305 a, in the midst of D₁ and D2, and of the machine.
R
n₁, spiral-spring of the point-bars, Fig. 285.
o, comb-shifting disk at the shaft t, Fig. 286.
o,, ratchet-wheel of the front guide-bar, Fig. 286, left side.
on ratchet-wheel of the back guide-bar, Figs. 285. 286.
On, comb-shifting disk at the shaft t, right side, Fig. 286.
p, locker-bar, Figs. 284, 288, 289, 309.
P., bolts or rails to which the adjusting screws m, and ms are fixed, Figs. 300, 301, 286.
P₂ socket-pieces at D₁ and Dr Figs. 284, 285, 286.
q. locker, Figs. 284, 288, 289, 309.
qn supporting arms or stays of the bolt-bars, Figs. 284, 285, 287, 300, 301, 302, 303.
q₁, screws for supporting the bolt-bars, Fig. 317.
r, sliding roller of the large heart-shaped disk U, Figs. 284, 288, 289
(r,) sliding roller of the large heart-shaped disk U,, in Figs. 358 and 359.
r1, roller of the locker-disk v₁, Fig. 286.
T2, roller of the locker-disk U₂, Fig. 286.
T3, rowels at the bar D, Fig. 286.
r4, sliding roller of the shell-wheels R2 and R₃, Figs. 288 and 289.
8, arms by which the point-bars are connected with the supporting bars S, and S2, Figs. 287, 288, 285
81, 82, dented wheels at the axis W, Fig. 286.
t, shafts to which are fixed all ratchet-wheels and disks, Figs. 285, 286, 288, 289.
& t1, } dented wheels at the axis t, Fig. 286.
u, pivot on which the pushing levers x₁ and x₂ move, Fig. 285.
us, angular lever of the front guide-bars, Fig. 295.
262, angular lever of the back guide-bars, Fig. 295.
us, pushing lever of the front comb, to the right, Fig.
286.
u,, pushing lever of the front comb, to the left,
v, motive power or quarter-wheel of the lockers, Figs. 284, 311, 312.
v₁, locker-disk for the back locker, at the axis W, Fig. 286.
v₂, locker-disk for the front locker, at the same axis, Figs. 284, 286, 288, 289.
w, shafts to which the lever-arms h, h₁ and h2, are fixed, Figs. 386, 289, 358 and 359.
so,, shafts to which the cradle-arms I, and cradle-pieces I, are fixed, Figs. 284, 285, 286, 287.
20₂, dented wheel of the lace-beam, Fig. 285.
x, socket of the shaft 10, Fig. 284.
I1, pushing lever of the front guide-bar,
~
Figs.
286
and
295.
xq. pushing lever of the back guide-bar,
xₙ x3, angular levers for pushing the bolt-bars, Figs. 285 and 287.
y, bolt or rail, through which the common peg of the angular levers u₁ and Ug are put, Fig. 295.
y, adjusting screw of the point-bar, on which the upper fork of the bar S₁ is acting, Figs. 288, 289.
Yr adjusting screws of the point-bar, which strike against the side-frame A and A1, Fig. 285.
2, a trigger, Fig. 286.
:
5
}
dented bars for the lockers, Figs. 284, 287, 311, 312, 314.
a, foot-screws of the bolt-bars, Figs. 284, 285, 286, 287, 300, 303.
B, notch in which the middle stays e are running, Fig. 317.
I.
d,
}
iron pegs at the lower fork of the bar S1, Figs. 288 and 239.
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BOBBINET MACHINERY.
121
Machines for manufacturing broad plain Bobbinet.
The latest and most approved construction of these machines is according to the double-locker sys-
tem. Machines of this system can be arranged for any breadth of the piece, and are working for
weeks, and even months, with great precision and quickness, without any interruption which might
be produced by irregularity in the mechanism. Being commonly of considerable breadth, the motive
power must be very strong; therefore it is driven either by water or steam.
In the following, we give a description of a machine for webs 8 quarters wide, constructed according
to the double-locker system, and illustrated by Figs. 284 to 375, in the most careful manner. The illus-
trations are given with all particulars required, which may enable the mechanic to draw upon a large
scale from them.
The machine for manufacturing plain bobbinet, though being the most simple of all bobbinet
machines, belongs, however, by its construction to the most complicated ones. Its web is represented
by Fig. 360 on a large scale. One and the same thread is marked along its way by the same letter.
The threads f are extended up and down, or proceed downwards in serpentine lines, while the two
other sets of threads k and k₁ proceed from the right to the left, and from the left to the right in
slanting directions. By this, the twisting and interlacing of the threads is produced. The perpendicular
threads in the figure, which are parallel to the border, may be regarded as the warp, and the two sets
of slanting threads as the weft, in comparing bobbinet with a common web. The straight warp-
threads receive their twist from the tension of the weft-threads, twisted obliquely round them alter-
nately to the right and left.
This seemingly simple union of the threads requires, however, a very complicated mechanism, which
must be understood before the operation of the machines can be comprehended, and their result ex-
amined more closely.
At the chief frame A A, B B, C, are shown all parts of the machine. (See Figs. 284 to 287.) Fig.
284 shows the machine near its centre in transverse section Fig. 285 gives an end view of the right
side of the machine, before which the operative has his ordinary place. Fig. 286 gives a front view of
the fore side, and Fig. 287 an end view of the left side.
Two and two opposite sides of the frame are completely equal to each other, viz: A and A1, B and
B1; all four are united by screw-bolts. The joist C, Figs. 284 and 286, binds the upper ends of A, A1
together.
The warp of the web consists, as has already been mentioned, of parallel running warp-threads,
which are coiled round the warp-beam. In proportion to the proceeding of the fabrication, the warp is
unwound, while at the same time the finished lace is wound upon the lace-beam. The lace-beam is
placed above the warp-beam, as may be seen by Z and G in Fig. 284, where they are shown in trans-
verse section.
The ends of the warp-beam (represented in Fig. 284, in transverse section, and with the warp wound
upon it) are provided with strong rollers or disks; and its pivots run in iron sockets, which are fastened
to B1, and in the figure marked by g. The disks R are grooved to receive the cord S, one end of
which is fastened at B, while the other end runs vertically downwards, and is fastened to the lever H.
This lever turns on a pivot at the post B1, and its fore end bears the weight Q. This contrivance
serves to keep the warp in due tension while being wound off the warp-beam. This unwinding takes
place in four rows of warp-threads, (see Fig. 284,) for which purpose the single threads pass the eyes
of a kind of reed F. Figs. 284. 286, and 350, 351, consisting of single pieces of latten-plate, called brasses,
and placed one by one into the grooves of two long staves, bound together at the ends and in the midst.
The brasses are regularly perforated in four rows. The reed is oblique, and close above the warp-
beam loosely fastened, (see Figs. 284 and 351,) that it (if required) may be lifted a little, and not slip
down. The warp-threads are marked with f. Fig. 350 gives the view of a brass; Fig. 350 a trans-
verse section of a row of eyes; and Fig. 351.
The fourfold divided warp passes vertically upwards between two parallel guide-bars, and unites
close above them into two series of warp-threads, two and two series of the warp being drawn into two
series of guides. The guide-bars (see Figs. 284, 286, 330, 331, 332, 333, 334, 335, 336, 337) are placed
along the whole machine and supported at both ends and in the centre, that they may retain their
parallel situation and their relative position. They are in all figures marked with a and b-a marking
the front and b the back guide-bar. Both guide-bars are liable to lateral movement, by which a
lateral shifting of the warp is effected. The series of guides c and d consist, like the reed F, of single
pieces put together lengthwise. The number of the pieces, which are to be of entirely equal breadth,
depends upon the number of the warp-threads, or of the breadth of the texture.
Every single piece, consisting of a mixture of lead and zinc, is provided with an equal number of
guides, being made of iron or steel wire, and cast together with the pieces in uniform distance from
each other. Fig. 334 gives a front view of a single lead-piece in its position when screwed to the guide-
bar Fig. 335 a side view of it; Fig. 336 represents a single guide; and Fig. 337 an ear. Guides are
almost exclusively used, as by them the drawing in of the warp-threads is considerably facilitated.
The two series of guides c and d divide the warp into two opposite equal parts, of which the texture
is to be made. At the point where the texture begins both unite in one warp and are placed in one
plane. Each half extends over the whole breadth of the texture, the threads of each series having
double the distance between themselves, apparent in the texture.
This arrangemcnt is of the greatest importance. The lace-weaving is facilitated by it, and at the
same time some parts can be made stronger, which is of great avail regarding durability and quickness
of operation. Moreover, the inconvenience of entangling and tearing the threads is removed.
The texture begins near MN, where the interlacing and twisting of the warp and weft threads is
accomplished.
Fig. 360 shows the formation of the regular holes or meshes, completed by the round points of the
point-bars M and N, after the intertwisting of the warp and weft threads having been accomplished
16
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BOBBINET MACHINERY.
below. The formation of the meshes is effected round the points of the point-bars, and simultaneously
across the whole breadth of the warp in horizontal lines. For the formation of one row of meshes only
one point-bar is required. Both alternate in this operation, 80 that one point-bar holds the finished row.
of meshes, while the other takes up the next following, and thus they relieve each other continually.
In proportion to the proceeding of the formation of the rows of meshes, the texture is wound upon
the lace-beam. Figs. 284, 285, 286, 287,-288, 289, 321, 322, 328, and 329, will illustrate what is said
here.
The point-bars are marked with M and N,-the front bar with M, and the back point-bar with N.
Both are provided with points which are adapted to each other.
The points are cast in lead-pieces which are fixed to the point-bars by screws, (see Figs. 321, 322,
and 328, 329;) the last-mentioned figure shows a point-piece N separately. Every point-piece must
have exactly the same breadth as the lead-pieces of the series of guides c and d, whose number is equal
to that of the point-pieces. The number of points in each point-piece is likewise equal to that of the
guides in each lead-piece. By Fig. 328, it will be perceived that between the single points there is
room enough not only for the opposite points, but also for the intertwisting threads.
Z represents the lace-beam, running parallel with the warp-beam, and being of equal length, and of
equal or smaller diameter. It turns on pivots, whose sockets are placed in similar manner to those of
the warp-beam. See Fig. 286.
The successive turning of the lace-beam is effected by a regulator, moved by the machinery.
The finished lace passes on its way from the point-bars to the lace-beam across the rounded iron bar
D, Figs. 284, 286, 352, 353, and 354, which serves to support the texture. At both ends of it are
rowels r₃ (355) turning on small pivots. The pricks of these rowels enter the meshes close by the borders
of the texture, thus preventing its running together. The larger rowels R1, close above the smaller ones,
are intended for the same purpose.
The lace is, by its winding upon the lace-beam, on account of its tension, somewhat less broad than it
is when lying on the point-bars.
The union of the warp and weft takes place below MN, and is effected by two rows of weft-threads,
each of which is wound round a small bobbin, that passes between two and two warp-threads. Thus
there are two rows of bobbins which are moved round the warps; and in this way the intertwisting is
effected. The bobbin-rows stand parallel with the breadth of the warp, and either both rows before or
behind it; or one row before and one behind it.
That the bobbins may occupy these respective positions, they are pushed from one side to the other
on carriages and bolts. Each bobbin has its separate carriage and bolt; and two and two bobbins are
with their carriages behind each other, on one bolt. The whole series of bolts is called a comb.
The bobbins, carriages, and bolts, are of a peculiar shape, as may be seen by Figs. 284, 286, 288, 289
296, 297, 298, 306, 307, 308, 326, 338, 339.
Fig. 296, gives the side view of a carriage with inserted bobbin.
Fig. 297, section of a bobbin.
Fig. 298, carriage viewed from the other side, and without the bobbin.
Fig. 299, section.
Figs. 306, 307., and 308b, show a bolt.
Fig. 306, gives a side view of the bolt, when placed in the machine.
Fig. 307, represents its lower edge turned towards the warp.
Fig. 308, gives a section of the bolt at its opposite end.
The single bolts are, like the points and guides, cast in lead-pieces, each of which contains as many
bolts as there are points and guides in one lead-piece. The breadth of the comb-pieces is exactly equal
to that of the other lead-pieces.
Figs. 338, (view from behind,) 339, (front view,) and 326, (side view,) represent a comb-piece.
The small interstices between the single bolts receive the carriages, which thus, with their grooves,
are placed upon the bolts. See Figs. 298, 299, 306, 326, 338, and 339.
The bolt-pieces are by the side of each other screwed on a bar, and thus form together the comb.
One of such combs is placed before, and one behind the warp, and the distance between both is not
greater than required for the easy passage of the double row of warp-threads.
The bolts of both combs are exactly opposite each other, that the carriages may be pushed from one
comb to the other without obstruction.
The bolts are circular, to keep the bobbin-threads at an equal tension, while the carriages are pushed
to and fro.
The width of the carriages, compared with the inconsiderable distance by which their bolts stand off,
on both sides of the warp, permits this pushing from one comb to the other without any difficulty. Both
combs have their correct mutual position with reference to the centre of the circular line.
In the figures, the front comb is marked with L, and the back comb with L₁; the bars on which the
tembs are screwed, and which are called bolt-bars, are marked with K and K,, and the carriage-lines
1 th l and l₁. The carriage-line l, which is always nearest to the operative, is called the front, and l₁ the
back line. For this reason they use to say front and back carriage-thread series, or briefly front and back
carriage-threads, instead of bobbin-thread series, etc.
The unwinding of the threads and turning motion of the bobbins, is to be seen by Figs. 296, 297, 298,
and 299.
The swinging movement of the carriages on their circular bolts is not a continual one, but is made in
short regular intervals. The pauses occur as soon as the carriage-lines, coming from the one or the other
side, have passed the warp-threads and stand completely on their bolts. Meanwhile the shifting of the
warp-threads (not being hindered now by the carriages) to the right or to the left takes place. As soon
as the carriages pass the warp-threads, the regular twisting and crossing is accomplished, and at the
same time the mesh of net completed.
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BOBBINET MACHINERY.
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The swinging movement of the carriages is effected in the following manner. See Figs. 284, 288, and
289.
E and E1 are two bars, parallel to the carriage-lines, but somewhat longer, and their oblique side
turned towards them.
Both bars are, with their ends, placed so that they cannot shift their places. Figs. 284, 288, and 289
show the different positions which they occupy. They are close above the comb, seize the carriages,
and push them from one comb to the other, as soon as put in a swinging motion.
This motion is in consequence of. their moveable sockets being put in the rifts of the cradle-pieces I,,
which are moved backwards and forwards like a pendulum. See Figs. 284, 285, 286, 287, 340 to
344.
By Figs. 284 and 289, it may be seen that these pusher-bars never can pass the centre, but stop at
some distance from the warp before they make their retrograde motion. Thus the pushing of the car-
riages beyond the midst, cannot be effected by them; this must be done by the drawer-bars, or the blades
of the locker, (here called double-locker.) These are marked with q, and the locker-bar on which they
are screwed, with P. Fig. 294 gives a transverse section of the double locker-blades. The locker-bars
P are placed at both sides of the warps below the comb, towards the bolts of the carriages. The locker-
blades may be cast either each separately, or, more properly, both together, and then fastened to the
locker-bar by screws. Their material is brass, but the bars are made of wrought-iron. The length of
the combined locker-blades is somewhat exceeding that of the comb, and they therefore can seize a whole
carriage-line at the pointed ends of the carriages projecting from beneath the comb. See Figs. 284, 288,
289, 296, and 298. By a slight angular movement of the blades, the carriages, pushed to them by the
pusher-bars, are seized at their feet, and drawn across the midst of the machine through the warp-threads.
The movements of the pusher-bars and lockers are thus supporting each other, and by this, the swinging
of the carriages is completely effected. The lockers serve at the same time to keep back the carriage-
lines during the above-mentioned pauses, thus prevent them getting into the centre, and bringing the
warp-threads out of order during their shifting. The periodic angular movement of the locker is effected
by motive power, dented bars and eccentric disks acting upon the axis of the locker-bars. Figs. 284,
288, and 289 will more distinctly explain the operations of the single locker-blades.
In Fig. 284, both carriage-lines stand on the back comb. The front blade of the back locker holds the
hind-feet of the front carriage-line, and thus retains also the back carriage-line. The front locker is com-
pletely turned over, so that its blades by no means hinder the carriages from sliding on the front comb.
In Fig. 285, the front blade of the front locker has already drawn over the front carriage-line, and keeps
it on the comb. The back carriage-line is on the back comb, and is retained there by a blade of the
back locker.
In Fig. 286, both carriage-lines are on the front comb, and the back line, together with the front car-
riage-line, is retained by the back locker-blade. The figures also show the counter-movement of both
lockers, the necessity of the removal and height. of the locker-blades, etc. This highly ingenious con-
trivance is invented by Mr. Morley.
The chief parts of the machine, their movements and functions in general, are now known, and it will
hereafter not be difficult more to follow the movements, operations, and connection. But first, a stand-
point must be afforded, from which the whole progress of the machine can be overlooked. For this pur-
pose, it will be suitable to commence with the moment when a row of meshes is completed and seized
by the point-bars, and at the same time to notice the particulars concerning the rotation of the shafts,
wheels, and disks.
The great dented wheel V (with 48 cogs) at the principal axis W, makes three rotations during the two
movement-periods, in which two rows of meshes are completed. It is the same with the two dented
wheels 8, and Sq.
The large heart-shaped disk U, and the two small locker-disks v₁ and v₂ make likewise three rotations
in this time. Each rotation of these disks brings about four interrupted movements of the pushing and
locker bars. Every such movement causes a carriage-line to cross a comb. Consequently, for completing
one row of meshes, six movements of carriage-lines are required.
The dented wheels t₁ and t₂, (of the axis t,) which are turned by 8₁ and 82 have thrice as many cogs as
the latter dented wheels, and, for this reason, they make only one rotation, while the principal axis W
makes three. It is the same with the shafts t, and the pushing-wheels and lifting-thumbs connected
with them.
The notches and elevations of the pushing or notched wheels, occupy nearly one-twelfth of the pe-
riphery, if taken together.
In Figs. 345, 346, 347, and 348, their mutual position with reference to their notches and elevations is
shown, as they must be put on the shafts. This position corresponds to the moment which is represented
in the figure of the machines, in Figs. 284, 285, 286, and 287. The disks move in the direction of the
arrows.
The pushing-points of the levers are in a vertical plane going through the axis of the shafts t. Equally
marked points of the periphery of the pushing or ratchet wheels are during the movement entering this
vertical plane, and acting upon their levers simultaneously.
The ratchet wheels in Figs. 345 and 346, are, during a total rotation of the axis, (or during the com+
pletion of two rows of meshes,) pushing the front comb twice to the right and twice to the left; the
notched wheel 0,, Fig. 347, pushes in the same time the front guide-bar, and with it the front half of the
warp, thrice to the right and to the left, and the notched wheel 0₂ Fig. 348, does the same with the
back guide-bar and the back half of the warp.
The shell-wheel R₂ of the front point-bar (represented in Fig. 287, but omitted in Figs. 288 and 289)
has a position entirely opposed to that of R,, so that the indenture of the shell-wheel R₂ stands deepest
while that of R, stands highest. (See Fig. 289.)
The points 9, 10, and 11, of the lifting-thumb Q₁, (sec Figs. 288 and 289,) are, with reference to the
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BOBBINET MACHINERY.
simultaneous pushing of the ratchet-wheels, corresponding about the points 20, 22, and 12; that is to
say, as soon as the points 9, 10, and 11 are active, the points 20, 22, and 12 follow this movement in
succession. On the other hand, the edge of the indenture in the shell-wheel R, corresponds respectively
with 10 and about 16, its centre with 11 and 18, and its opposite edge with 19. The corresponding
points of Rs are respectively 10, and about 22, then 11, 12, and 13.
The relative position of all parts being thus correctly stated, we shall follow the various movements
from the moment when a row of meshes has just been completed, and the points are falling or catching
in the meshes.
Fig. 289 shows the positions of most of the chief parts in this movement; and there we see what
follows :-
The back point-bar is about to fall off. Both carriage-lines are on the front comb. The front half of
the warp assumes its usual position, (that is to say, its most frequent position.) Point 12 on 0₁ is under
the point of the lever x₁, (see Fig. 286.)
The back half of the warp has just now shifted from the left to the right, the lever x₂ being fallen off
from 12 on Or
The movement ensues. The back point-bar N lifts the row of meshes. The back carriage-line 1, goes
up to the back comb.
After the shafts t and W have made respectively one-twelfth and a quarter of rotation, a pause
ensues.
The point-bars have lifted up their rows of meshes almost entirely.
The back carriage-line is on the back comb. All carriages have made a comb-movement.
The front half of the warp retains its usual position, (see above;) the point 13 on 0₁ is advanced until
beneath the point of the lever.
The back half of the warp has shifted from the right to the left, (the pushing-lever x₂ has risen above
the prominence at 13 on 02) and assumes its usual position, (see above.)
The first movement is accomplished; and the different parts are in the position of Fig. 288.
The second movement begins. The point-bars are at rest.
The front carriage-line goes up to the back comb, where the back carriage-line moves higher up.
The shafts t and W make, respectively, one-twelfth and a quarter of rotation, and a pause ensues.
Both carriage-lines are on the back comb.
The front comb is pushed from the right to the left, the points 14 of o and O₂, being advanced to be-
neath the points of the levers.
The front half of the warp has shifted from the right to the left.
The back half of the warp retains its usual position.
The point-bars are at rest.
The second movement is accomplished.
The positions of the different parts represented in the figures, (with the exception of Figs. 288 and
289,) are corresponding to this moment.
-
The third movement begins.
The front carriage-line l returns to the front comb.
The front point-bar begins to leave its row of meshes. This curve from 9 to 10 of the lifting-thumb
acts upon the pin of the fork.
The shafts t make again one-twelfth of their rotation, and the pause ensues.
The front carriage-line is on the front comb, and has moved from the left to the right. The back
carriage-line is on the back comb.
The front half of the warp has shifted from the left to the right, and is in its usual position, as is the
back half also.
The front point-bar is lifted almost entirely out of the meshes.
The third movement is accomplished.
The fourth movement begins.
The back carriage-line goes up to the front comb.
The front point-bar is lifted out.
The shafts t make their fourth twelfth of the rotation, and the pause ensues.
Both carriage-lines are on the front comb, and move from the right to the left.
The front and back parts of the warp are in their usual position.
The front point-bar is about to lower.
The fourth movement is accomplished.
The fifth movement begins.
The back carriage-line returns to the back comb.
The point-bar lowers. The fifth twelfth of the rotation of the shafts t is made, and the pause
ensues.
The back carriage-line is on the back comb.
The front carriage-line is on the front comb, and has moved from the left to the right.
The front half of the warp is in its usual position, and the back half has shifted from the left to
the right.
The fifth movement is accomplished.
The sixth movement begins.
The front carriage-line goes up to the back comb.
The front point-bar is lowering, and six-twelfths or one-half of rotation of the shafts t ensues. Both
carriage-lines are on the back comb. The interchange or traversing of the carriages is accomplished.
The carriages have advanced to the right by one station.
The front half of the warp is in its usual position.
The back half of the warp has shifted from the right to the left.
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BOBBINET MACHINERY.
125
The front point-bar has lowered. It is now exactly in the same position as the back point-bar was
in the beginning of the first movement, (see Fig. 289,) and is nearly about to fall off.
The sixth movement is accomplished, and therewith a row of meshes completed.
These six movements constitute the first period of operations.
The next, or second period, comprises almost the same movements, with the exception of the comb-
shiftings, as will be perceived by the following explanation:-
The seventh movement begins.
The front carriage-line goes up to the front comb.
The front point-bar falls off, and lifts the seized row of meshes.
The shafts t make the seventh twelfth of their rotation.
The front carriage-line is on the front comb, and the back one on the back comb.
The front half of the warp has shifted from the right to the left; the back half is in its usual
position.
The front point-bar is lifted almost entirely.
The seventh movement is accomplished.
The eighth movement begins.
The back carriage-line comes up to the front comb.
The front point-bar is lifted.
The shafts t make the eighth twelfth of their rotation.
Both carriages are on the front comb.
The front half of the warp having shifted from the left to the right, assumes its usual position.
The back half of the warp retains its usual position.
Both point-bars are at rest.
The eighth movement is accomplished.
The ninth movement begins.
The back carriage-line goes up to the back comb.
The back point-bar begins to leave the meshes, and nine-twelfths of rotation of the shafts t are
made.
The back carriage-line is on the back comb, and the front line on the front comb.
The front half of the warp is in its usual position.
The back half of the warp shifts from the left to the right.
The back point-bar has nearly left the meshes.
The ninth movement is accomplished.
The tenth movement begins.
The front carriage-line goes up to the back comb.
The back point-bar is entirely taken out.
The tenth twelfth of rotation of the shafts t ensues.
Both carriage-lines are on the back comb.
The front half of the warp shifts from the right to the left, and the back half shifts from the left to
the right.
The back point-bar is about to lower.
The tenth movement is accomplished.
The eleventh movement begins.
The front carriage-line returns to the front comb.
The back point-bar lowers, and the eleventh twelfth of rotation of the shafts t ensues.
The front carriage-line is on the front comb. and the back line on the back comb.
The front half of the warp shifts from the left to the right, and the back half retains its usual
position.
The back point-bar is near its deepest standing.
The eleventh movement is accomplished.
The twelfth movement begins.
The back carriage-line goes up to the front comb.
The back point-bar attains its deepest standing. The last twelfth or a total rotation of the shafts t
is accomplished.
Both carriage-lines are on the front comb.
The front half of the warp is in its usual position, and the back half shifts from the left to the right.
The back point-bar is in its deepest standing, and about to fall off.
The twelfth movement is accomplished. A fresh row of meshes is completed, and is forthwith taken
up by the back point-bar.
With the twelfth movement the second period of operations is accomplished, and all is in the posi-
tion of Fig. 289. Hereupon the same circulation of movements and functions of the different parts
begins, and 80 on.
The following table will serve to render the just-described periods of movements still more con-
spicuous. The superscriptions of the columns will prove to be sufficient to explain the signification of
the letters; and it may only be remarked, that A signifies the front carriage-line, and B the back car-
riage-line. Each column contains two lines, filled either with points or letters, thus indicating the mutual
position of the concerning threads and carriages after every lateral movement. The asterisks (*) in
the column superseribed " Front comb," serve to direct the attention on the shifting of the comb.
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BOBBINET MACHINERY.
TABLE of the Periods of Movements.
First Period of Movements.
Front half
Back half
Movements.
Front comb.
of the
of the
Back comb.
Movement of the point-bar.
warp.
warp.
End of the 12th or beginning
The back point-bar is about to
of the 1st
B
a
b
fall off.
End of the 1st or beginning
b
The back point-bar has taken up
of the 2d
B
the row of meshes.
End of the 2d or beginning
a
b
of the 3d
B
Both point-bars at rest.
End of the 3d or beginning
b
The front point-bar is lifted ot ,
of the 4th
a
B
of the meshes.
End of the 4th or beginning
B
b
The front point-bar is about to
of the 5th
a
lower.
End of the 5th or beginning
The front point-bar is lowering
of the 6th
b
B
deeper.
End of the 6th or beginning
b
The front point-bar has lowered
of the 7th
B
deepest and is about to fall off.
Second Period of Movements.
End of the 7th or beginning
a
b
The front point-bar has lifted the
of the 8th
B
row of meshes.
End of the 8th or beginning
b
of the 9th
B
Both point-bars at rest.
End of the 9th or beginning
The back point-bar is lifted out
of the 10th
a
b
B
of the meshes.
End of the 10th or beginning
a
b
The back point-bar is about to
of the 11th
B
lower.
End of the 11th or beginning
b
The back point-bar lowers
of the 12th
B
deeper.
End of the 12th or beginning
The back point-bar is about to
of the 1st
A
B
b
fall off.
A comparison of this detailed statement, with the illustration given in Fig. 360, will afford a still
clearer view of the intertwisting and crossing of the warp and weft or carriage-threads.
In Fig. 360 the warp-threads are marked with f. They proceed downwards in serpentine lines, and
receive their contorsion from the tension of the weft-threads twisted obliquely round them alternately
to the right and the left hand. Before this union, and beneath the point-bars, the warp-threads are
tentered vertically. So that the front half of the warp may be better distinguished from the back half,
the threads of the former are hatched.
The front carriage-threads are marked with k, and the back threads with k₁. The figure shows the
texture on a very large scale. The web consists of nine warp and nine weft threads. Five threads
belong to the back half of the warp, and four threads to the front half.
Each (horizontally directed) row of meshes contains four holes or meshes.
The hatched circles within the meshes represent the points of the two point-bars, and are marked
with M and N.
Description of an eight-quarters stripe machine.-Machines of this kind furnish bobbinet stripes or
quillings, forming one broad piece during the fabrication, but which afterwards are separated from
each other.
As these quillings or edgings, for the sake of beauty and solidity, must be, as it were, without a seam,
this manufacturing requires a particular contrivance in the bobbinet machines.
The above-described double-locker machine may easily be arranged for manufacturing quillings; and
the most practical and suitable contrivances for this purpose are those invented by Mr. Croft.
In Fig. 369 are represented two stripes of equal breadth, and united in such manner as they appear
in the whole piece on the lace-beam. The borders or selvages are hatched and marked with fs and for
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BOBBINET MACHINERY.
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The connecting thread, running in zigzag from one mesh to the other, is marked with k₂, and the other
warp and carriage threads respectively with f and kk₁.
Each stripe being a plain narrow lace in itself, and the carriage-threads proceeding in their slanting
directions, separately in the one and in the other, of course a contrivance is required in order that the
carriages may turn back at the two inner selvages as well as at the two outer ones. This and all
other required arrangements are illustrated by Figs. 361 to 394.
Fig. 378 represents a double-locker stripe machine in transverse section, in which latter Figs. 385, 386,
387, 388, and 889, are also given. The most essential parts of the machine are to be seen in Fig. 378.
Beginning from below, there will be perceived two warp-beams, G and G, Round the larger one is
wound the warp for the plain texture, and round the other are twisted the commonly somewhat stronger
selvages fs and for In case the latter should be of equal thickness as the other warp-threads, one
beam would be sufficient.
The warp-threads are to be drawn through the kind of reed F, and thence through the series of guides
c and d, which are fastened to the guide-bars a and b.
The selvage-threads are only laid over the wooden framing-staves of the reed F, (see Fig. 878,) and
then (on account of their peculiar lateral movement) drawn through particular iron or brass ears, (one of
which is represented by Figs. 391 and 392,) called selvage-guides, which are fastened to the guide-bars
as and b. The selvage guide-bars are provided with similar sockets, supports, adjusting screws, levers,
and springs, as a and b.
The warp is not divided into two equal parts as in the machine described above, but is drawn through
the front and back guides c and d unequally divided, and this in such a manner, that in the front warp.
half one, and in back half two, warp-threads are omitted at every border of the stripe. The corre-
sponding guides, in the series of guides, are broken off as superfluous.
The selvage-threads, on the other hand, are equally divided, drawn through the series of guides cs and
d₃, yet those marked with fo (see Fig. 369) exclusively through the front, and those marked with fs
through the back series.
Between the combs L and L₁ all warp and selvage threads are drawn up in two rows, and led to the
points n of the point-bars M and N, beneath which the texture is formed, after which it proceeds to the
lace-beam.
The comb and the lockers, and locker-bars p and q, are set up in the usual manner.
The carriages are likewise put in with two lines, odd carriage, etc., as has been described above.
Yet in the back line, right opposite to the selvage-threads, there are also the turn-again and whipping
carriages, briefly called whipper-carriages, with the thick and strong connecting threads kg, (see Fig.
309.) The whipper-carriages make upon the whole the same movements as the other carriages, with
the only difference that they do not shift their places, but are running to and fro in the same bolts.
During the shifting, they remain in the back comb, while the other carriages change their places in
each stripè-section.
Before their peculiar movement, (illustrated by the figures from 378 to 382,) during the shifting, can
be explained, some parts and contrivances connected with it must be viewed.
Close beneath the locker-bars p are parallel with them the so-called picker-bars, to which the pickers
p, are fastened by screws. The picker-bars have exactly such sockets and supports as the locker-bara.
At the one end is fixed a short arm e₁, moved by the drawer-bar o, by which the picker-bar, with the
pickers, can be put in a slight angular movement.
The pickers, made of stiff hammered iron or brass, Figs. 392 and 393, are performing here the func-
tions of the locker blades in the above-described machine, as they, like them, seize the heels or catches
of the carriages and push the latter onward, or respectively set them in their places. They, more-
over, serve to regulate the movements of the whipper-carriages, and are to be advanced as far as
possible towards the midst, yet in such manner that they may not impede the series of guides in their
lateral movements.
To retain the whipper-carriages on the back bolt-bar, the back pusher-bar E1 must be placed by a
particular contrivance, which is illustrated by Figs. 378 and 381, and especially by Figs. 885 and 389.
The pusher-bar E1, made of strong iron or spring steel plates, is at its long outsides strengthened by
a rib of wrought-iron and provided with a pivot, by means of which the bar is placed in the sockets of
the cradle-pieces I₁ in Figs. 284, 285, 286, etc. The bar has narrow but deep notches, intended to receive
the whipper-carriages while the other carriages are shifting their places; but as soon as this shifting is
accomplished, the whipper-carriages are let out, and the notches are closed by the covers d₄, which are
fixed to the guide-bar ga, and represented in Figs. 388 and 389. The covers are made of thin iron
plate. The guide-bar I' is, by means of iron pieces en fixed to the above-mentioned rib in such manner
that it is easily to be moved sidewise, and keeps the covers close upon the notches. The bar is con-
stantly attracted or drawn by a small but sufficiently strong spiral spring, fixed with its end to the
pusher-bar E₁. The iron pieces e₂ and the slits of the guide-bar Is, are squared thus, that the covers
are exactly upon the notches as long as the spring is acting. Fig. 385 represents this movement
The uncovering of the notches is effected by a lateral movement of the guide-bar g, to the right, and
this movement is brought on by the action of a lever on the pivot or tenon a, at the bar.
Figs. 390 (giving a side view) and 391 (horizontal section close above the comb) serve to illustrate
this movement. K is the front bolt, which, in the moment of the shifting, moves from the right to the
left with the comb L At its lower edge is applied the trigger hs which grasps the short one of the
two arms of the lever F, The turning takes place on the pivot 8₂ fixed at a suitable place in the frame.
The long lever-arm, bent exactly in conformity with the curve of the comb, and placed in such manner
that it is tight beneath the bar E₁, lies close to the left side of the tenon a.
Thus as soon as the bolt-bar K is moving to the left, the long arm of the lever F,, moving to the
right, presses against the tenon a,, overcomes the power of the spiral spring, pushes the guide-bar g₃ to
the right, and opens the notches of the pusher-bar.
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BOBBINET MACHINERY.
The notches must be kept open until the shifting is accomplished. But the bolt-bar turning again
from the left to the right, after the first quarter of the shifting movement, and, consequently, the long
arm of the lever F, making the inverse movement, the covers would close the notches again and bring
about confusion, if there had not been made a contrivance for preventing it. The chief instrument of
this contrivance is the parrying-ledge h₄, screwed on the back bolt-bar. Its position relative to the
lever F, and the tenon a, is shown by the Figs. 390 and 391. The tenon a, leans against the parrying-
ledge as soon as it is pressed by the lever F2, and does not give way until the shifting is accomplished.
The positions of the tenon a+ marked with dotted points in Figs. 390 and 391, will sufficiently illustrate
this statement.
We shall now take a view of the peculiar movements of the whipper-carriages in the moment of the
shifting.
Fig. 378 represents the concurring parts in the movement when the shifting of the front comb begins.
Both carriage lines are on the back comb.
In the next movement the comb makes its lateral movement; the lever F, acts upon a+ and the
notches of the pusher-bar E, are opened. Simultaneously the back pickers are, by the angular move-
ment of the picker-bars, moved upwards. They now seize the shifted carriages at their beels or catches
and push them onward, see Fig. 379, while the other carriages remain at their places, and the whipper-
carriages (marked with k₂) pass into the notches of the pusher-bar E1.
Now the movement of the pusher-bar and locker begins; E, pushing onward those carriages, which
are not retained by the pickers, and the back locker lowering. As soon as the outer locker-blade is
within the back heels of the retained carriages, the pickers move downwards, the just-mentioned
carriages are seized by the outer blade of the back locker, and the carriage-movement ensues in the
usual manner. The front locker draws the carriages, pushed to it by the pusher-bar E1, up to the front
comb, where, opposite to each whipper-carriage, one common carriage is lacking, (which may appear a
matter of course by the above given statement,) and is instead of this in the back line of it. The back
carriage-line on the back comb is complete, and has behind itself the line of the whipper-carriages which
had been retained in the notches of the pusher-bar E1. (See Fig. 380.)
The comb moves back; the carriage-movement ensues; the back pusher-bar causes all carriages,
without any exception, to move onward; the back locker falls off and the front locker seizes the
carriages presented to it and draws them up to the front comb. But just before the front locker seizes
the heels of the carriages, the back pickers move upwards again, and consequently retain the whipper-
carriages on the back comb. Meanwhile the other carriages have been drawn up to the front comb,
where now two lines are, of which the inner one is complete, while in the outer one as many carriages
are lacking as there are whipper-carriages on the opposite side. The position of the concurring parts in
this movement is represented by Fig. 381.
The back pickers are thus, in this period of movements, performing the function of the back locker,
which (as is shown by Fig. 381) has completely turned round, and cannot, for this reason, retain the
whipper-carriages.
As soon as now the front comb has moved again from the right to the left, the front pickers spring up,
and, seizing the (not in pairs) standing carriages on the front comb at their heels, press them upwards
until their back heels or catches are beyond the outer blade of the front locker. (See Fig. 382.) The
back pickers remain in their position represented by Fig. 381. Then the usual carriage-movement
begins, and before the front comb moves from the left to the right, the front as well as the back pickers
fall off. The comb-shifting ensues, and now both carriage-lines on the front and on the back comb are
complete. The interchange or traversing of the carriages throughout the whole width of each texture-
stripe has occurred, and the movement of the carriages of the complete lines continues in the usual
manner until the shifting takes place anew.
This shifting, i. e,, the interchange or traversing of the carriages in the texture-stripes, is indeed not
easily to be understood; however, the following statement will prove adapted to render the matter
pretty clear.
The common carriages are marked with a, b, c, d, e, f, g, h, k, and the whipper-carriages with kg;
their number is in conformity to the pattern in Fig. 369. The position of the carriages and combs is,
according to Fig. 378, the following:
k,
back comb.
First Position
after the first shifting of
the front comb.
Commencement.
front comb.
The big points represent the concurring places for the carriages. As soon as the carriages are on
the front comb, their position is the following:
kg
back comb.
First Position.
End.
front comb.
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After the comb's lateral movement to the right, the carriages stand thus:
k₃
k₃
abedeabed
}
back coml.
Second Position.
-
Beginning.
k h g f khgf
}
front comb.
This 1- saition corresponds to Fig. 380; yet as soon as the back carriage-lines have passed the front
comb, the position is the following:
kg
kg
}
back comb.
Second Position.
-
End.
abed abcde
khgf
}
front comb.
khgf
The comb moves to the left, and now the carriages stand thus:
k₃
k₃
}
back comb.
Third Position.
-
Beginning.
a
b
c
d
e
3
c
d
e
}
front comb.
k
h
f
k
h
g
f
This position corresponds to Fig. 381. The carriages move up to the back comb, and their position is
now the following:
}
back comb.
bcdekbedek
Third Position.
-
End.
akhgfakhgf
}
front comb.
The comb moves back, and the shifting of the carriages is now accomplished; for the position is
thus:
bcdekbcdek
}
back comb.
Fourth Position.
a
khgfakhgf
}
front comb.
&c, &c., &c.
This statement shows at the same time clearly, that all carriages, as for instance, e in the first posi-
tion, or as after the shifting f in the fourth position, which are with the whipper-carriages in one and
the same bolt, are doing the business of whipper-carriages.
At the ends of the carriage-lines no whipper-carriages nor pickers are required, because the hold-
fast contrivance, applied here, together with the notches of the lockers, supply the action of the
pickers.
The above explained interchange or traversing of the carriages is rendered necessary by the men-
tioned order of the warp-threads, and that the stripes of the texture may be provided with seams.
In manufacturing plain broad pieces, the front half of the warp containing one thread less than the
back half, there must be in a pattern like that of Fig. 369, four front and five back warp-threads in
each stripe. Further, the borders or selvages of plain broad pieces being made of the end-
threads of the back warp-threads, consequently the seam-threads of the stripes must likewise be
contained in the back half of the warp. But as here, on account of the connecting thread, (running in
zigzag,) the left seam-thread of a stripe must alternately pass over two bolts, these threads are to be
drawn through particular guides adapted for this movement.
17
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BOBBINET MACHINERY.
The lateral movements of the guide-bars are in the usual manner prepared by ratchet-wheels, levers
and angular pieces, or swing-bars. But for effecting the just-mentioned movement for the particular
guiding of the seam-threads, the stripe-machine must be provided with two ratchet-wheels more,
which are fastened at the axis t, to the right of the machine. Besides these, there are required two
other ratchet-wheels for the movement of the pickers, which are fastened at the same axis within the
dented wheels t₁ and t₂ (See Fig. 286.) Sometimes the last-named wheels are arranged for this pur-
pose in the manner illustrated by 81 in Fig. 390.
The figures from 370 to 377 represent all ratchet-wheels of the double-locker stripe-machine. The
directions of the arrows indicate those of the movements. The various acting points in the twelve
different movements of the concurring parts are marked with ciphers. Equal marked points are simul-
taneously acting. Point 1 corresponds to the acting point indicated by Fig. 378.
Fig. 370 represents the right ratchet-wheel for the lateral movement of the comb; Fig. 371 the left
one of this description; Fig. 372 the front ratchet-wheel for the warp-threads, and Fig. 374 the back
ratchet-wheel for the same purpose. (These four wheels, already known by the description and illus-
trations of the broad plain bobbinet machine, are delineated here once more, in order to facilitate the
view of the whole.) Fig. 373 represents the front ratchet-wheel for the seam-threads; Fig. 375 the
back ratchet-wheel for the same purpose; Fig. 376 the back ratchet-wheel for the pickers, and Fig. 377
the front one of this description.
Following in the order of numbers the indentments of the ratchet-whecls, it becomes apparent that
during the twelve different movements of the two principal movement-periods, (in which two rows of
meshes are completed,) the shiftings of the warp-threads occur simultaneously, and in a successive
order. Still more perspicuous the simultaneous operations of the ratchet-wheels will appear by sup-
posing their peripheries to be stretched out into a straight line, as has been done in the following sketch.
By the lateral shiftings of the warp-threads, and by the interchange or traversing of the carriages,
the formation of the web is effected; and all the intertwistings and decussations of the threads follow
each other in the same order, as has been sufficiently explained above. The connection of the seam-
threads with the connecting thread his, (Fig. 369,) is not brought on by perhaps a lateral movement of
the latter, but only by the lateral movements of the seam-threads. Thus the intertwisting of ks and f
(in the midst of the figure) is effected by a single shifting of the latter towards the former thread, (ex
plained by Fig. 373,) while the intertwisting of the left seam-thread fo is effected by its double-shifting
(See Fig. 375.)
The positions of the warp-threads towards each other and towards the carriages in the two principal
movement-periods, are exposed in the following statement. In this a, b, c, d, e, f, g, h, k signify the
common carriages, k₂ the whipper-carriages; the asterisks (*) signify the back seam-threads; the
simple crosses (+) the front seam-threads; the large points (.) the common front and back warp-
threads; and the vertical dashes (1) the void places for the carriages. The statement corresponds to
the texture of Fig. 369.
First Movement. Acting point 12.
b
d
k₁
a
b
c
d
his
back comb.
back seam-threads.
back warp-threads.
front warp-threads.
+
+
front seam-threads.
g
g
front comb.
Second
Movement.
Acting
point
1.
(Position
as
in
Fig.
378.)
b
c
h₃
a
b
c
his
back comb,
h:
1,
g
lc
1
g
back seam-threads,
warp-threads,
Shifting.
+
+
front seam-threads,
front comb,
Third Movement.
Acting pc: it 2.
k₃
k₃
b
d
b
c
d
back comb,
back seam-threads,
warp-threads,
Shifting.
+
+
front seam-threads,
h
front comb,
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BOBBINET MACHINERY.
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Fourth Movement. Acting point 8.
kg
h₃
back comb,
back seam-threads,
warp-threads,
Shifting.
+
+
front seam-threads,
e
d
a
h
g
k
1a
front comb,
g
Fifth Movement. Acting point 4.
b
c
kg
b
c
d
k₃
back comb,
c
back seam-threads,
warp-threads,
Shifting.
+
+
front seam-threads,
a
g
k
h
g
front comb,
Sixth Movement. Acting point 5.
b
c
kg
b
c
d
e
k₃
a
k
h
g
k
back comb.
h
g
back seam-threads.
warp-threads.
+
+
front seam-threads.
~
front comb.
Now the first principal movement-period is finished, and one row of meshes is completed. The
point-bars take up the completed row.
Seventh Movement. Acting point 6.
b
k₃
b
c
d
k₃
back comb.
back seam-threads.
+
+
g
h
g
front comb.
Eighth Movement.
Acting point 7.
back comb.
*
back seam-threads.
warp-threads.
+
+
front seam-threads.
b
k₃
b
d
e
h₃
h
front comb.
g
h
g
Ninth Movement. Acting point 8.
b
d
kg
b
c
d
e
~
back comb.
k₃
back seam-threads,
warp-threads.
+
+
front seam-threads.
g
k
h
g
front comb.
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BOBBINET MACHINERY.
Tenth Movement. Acting point 9.
b
kg
b
c
d
c
k₃
back comb.
I
h
h
g
back seam-threads.
warp-threads.
+
+
front seam-threada.
front comb.
Eleventh
Movement.
Acting point 10.
b
d
back COL b.
his
c
kg
back seam-threads.
warp-threads.
+
+
front seam-threads.
a
h
g
front comb.
Twelfth Movement. Acting point 11.
back comb.
back seam-threads.
warp-threads.
+
+
front seam-threads.
b
c
kg
k₂
back comb.
a
h
g
h
g
Now the second principal movement-period has finished, a fresh row of meshes is completed, and forth-
with taken up by the back point-bar, and in this manner the cycle of movements is continuing.
The points of the point-bars take up the completed meshes in the usual manner, only two points in
the midst are somewhat bent sidewise to give room for the connecting thread. (See Fig. 394.)
The breadth of the stripes is commonly fixed in conformity with numbers which coincide with the
number of meshes running diagonally. Thus, for instance, the stripes in Fig. 369 would be marked with
No. 8.
Figured bobbinet (or design bobbinet) is manufactured in three different ways :-
The common plain bobbinet is interwoven with embroidering or twisting threads. This inter-
weaving can be done at single spots, as well as in continued lines. The first manner produces points
or spots regulated by groups and figures of various descriptions; and the second manner produces orna-
mental stripes either in serpentine lines, or in zigzag, or otherwise arranged. The ornamental or
embroidering threads consist usually of thick or colored yarn, in order that the pattern may have a
better relief.
Machines for manufacturing bobbinet of this description, are: Sneath's improved single-locker ma-
chine; Heathcoate's patent machine; Summer's lever machine; Sewell's roller machine; Draper's ma-
chine, and White's improved machine.-The arrangements of these machines are very different, and it
would lead us too far, to give any description whatever of them here. Heathcoate's machine is connected
with a so-called tatting machine, by which the interweaving of ornamental threads is performed.
The simple intertwisting of threads in the plain bobbinet is altered in such manner, that at certain
points of the web. larger holes or meshes are made, surrounded by common smaller ones. Some pat-
terns of this description are called grecian net, the honey-comb open work, and the roseau tull.
The manufacturing of these webs requires, of course, more or less complicated arrangements in the
machinery. Their chief peculiarity is, that the warp is to be divided in more than two parts, which have
their lateral movements independent of each other. Frequently the movement of the carriages is in
certain movement-periods somewhat altered too, similar to the case of the stripe-machine, which
may indeed be considered as producing figured or design bobbinet, if the zigzag connection be regarded
as a figure.
The arrangements of the first and second systems are combined, by which we obtain patterns with
larger, and meshes with ornamental threads. Draper's machine is partly adapted to them. Upon the
whole, the machinery is very complicated; and for this reason, almost everywhere the lever and single-
locker systems are applied, because machines of this description can be more conveniently arranged and
altered than double-locker machines.
BOILER PLATES, Machine for punching. Fig. 395 is an elevation, Fig. 396 a plan, and Fig. 397 a
side view of a punching-machine on a very improved principle, whereby the plates required for boilers
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BOILER PLATES.
133
and other purposes may be punched with the greatest possible accuracy, insuring at the same time very
superior workmanship and great dispatch. It is usual in all ordinary punching-machines, first of all to
mark out the rivet-holes in the plate, by a template, with white paint, and then to place it as near as
the eye will permit under the punch; by the contrivance of this machine, this operation is entirely
dispensed with, it being only necessary to fix the plate to a travelling table, and then to adjust the
various parts of the machine to the proper distance required between the rivets.
The large cast-iron frame P carries the several parts of the machinery, and also the two plummer-
blocks for supporting the bearings of the lying shaft a, running the whole length of the building, for the
purpose of working other machines; this frame is securely bolted to the wall, which, added to its own
weight. gives it great stability.
On the shafts a, connected together by the two coupling-boxes, is placed the crank b, the motion
being communicated through the crank-pin to a connecting-rod c, to which is attached the upper lever d,
being always at work, while the shaft a is revolving; the fulcrum of this lever is on the frame p. A
lower lever e for raising and depressing the punching frame f has also its fulcrum on the same frame;
this last lever working only when the punching operation is being performed. On the top of the
frame P is a lever and long rods e' for engaging and disengaging the machinery. The side view epre-
sented by Fig. 397, shows the machine at work, and by drawing down the lever e', connected by the
rods to the counterbalance weight, which will allow it to remain steady in any position, they are
disengaged from the pin on the lever d, which at once ceases to communicate the motion to the lower
or punching lever e; thus it will easily be understood that those parts of the machine constantly at
work, are the lying shaft a, the crank b, the connecting-rod c, and the upper lever d.
The slide f for carrying the punches, works between V's, Fig. 396; one is fixed to the frame p by
adjusting-screws, both on its face and sides, and by the curious shape given to the end of the lever e,
this slide is made to rise and fall, the counterbalance weight and lever g being connected by two short
links; on the bottom of the slide is screwed a small frame for carrying the punches, which may be
taken out and replaced by others. The dies i, in which the punches work, are placed in a frame bolted
to the frame p, and by unscrewing the small adjusting-screws, these may be taken out and replaced by
others suitable to the different-sized punches that may be required. On the under side of the frame p
is screwed a small stop, by which the circle punched from the plate is forced out as the slide rises.
In the front of the machine is placed a long table, supported by the carriages o, consisting of two
columns and diagonal frame, having bolted to them two long bars, upon which the moveable table is
made to slide; this table, as will be seen by Fig. 396, has a number of holes by which the plate to be
punched is secured by clamps; it is advanced by the rope or chain n passing under the pulley, Figs.
395 and 396, and over a second one hung from the ceiling of the building, to which is connected a
weight sufficiently heavy to draw forward the table and plate fixed to it; after travelling the length of
the table o, it may be brought back by turning the winch-handle and spindle l, on which is a pinion for
working the rack, fixed to the under side of the moveable table m.
By a very ingenious contrivance, forming part of this machine, the rivet-holes of boilers may be
punched to very different pitches, a thing very much wanted in such cases as the repairing of old boilers,
or replacing an old plate by a new one, where it is of the utmost importance to have the rivet-holes
coinciding with the greatest accuracy, which may be better understood by supposing that in the length
of a plate, one, two, or three additional rivet-holes may be required, which distance would have to be
equally divided in the whole length of the plate. A description of this part of the machine will fully
show how this operation is performed. On the end of the punching-lever e is screwed a small plate
with a pin j', adjustable by a screw working in the short mortise, Fig. 397 on the frame p is bolted a
fulcrum piece for the lever and counterbalance weight j to this lever a long rod is connected at its
lower end, passing under the table in, and the lever r is fixed to it, as will be seen by the dotted lines
in Fig. 396; it has also two stops or projecting pieces r' r' on its surface. A second lever 8 has its
fulcrum fixed to the table o, one end of this lever being connected to the lever r, while the opposite end
has on its surface two small pins 8' 8'; the fulcrum 8" of this lever is adjustable by the two small
screws shown in the plan, Fig. 396. A long notched bar k is fixed to the under side of the table m by
screws, and the bar t has its fulcrum t' also fixed to it; this latter bar t is moveable on its centre, and
may be placed at any angle by an adjusting-screw working in a mortise t", where it may be fixed in
any required position, as will be seen; it is by the angle given to this bar, that the regular increase of
distance is obtained between the rivets. This is effected in the following manner :-As the lever c
works on its centre, the pin j' to which it is fixed, strikes as it descends on the end of the lever j; its
motion is then communicated to the long rod, passing under the table, for working the lever r back-
wards and forwards, it being fixed to the rod; as the latter lever moves, it alternately engages and
disengages the stop or projecting pieces r' qu' from the notched bar, allowing it at the same time to slide
forward the distance between the rivets; while the bar t placed at the required angle, and working
between the pins s' 8' on the lever 8, immediately effects the distance travelled by the lever r, which it
shortens; by this arrangement the machine is made quite self-acting, but it may also be worked by the
handle on the end of the rod j.
When it is required to change the punches 1. for different-sized holes, it is necessary, when replaced,
to adjust them to the greatest possible accuracy in the dies i; this could not be done without stopping
the whole line of shaft a, were it not for a provision made for that purpose; in such a case, the key in
the upper part of the connecting-rod c is withdrawn, a block of wood is then placed between the frame
and the lever d, whose fulcrum is on the side of the frame p, upon which it rests. It is of course under-
stood that the punching-lever d is at rest, being disengaged from the pin é; the result of this is the
working of the long mortise of the connecting-rod up and down on the pin, without communicating any
inotion whatever; and by the lever q, worked gently by hand, and shown dotted in Figs. 396 and 397,
the punching-lever e can be raised and lowered, communicating its alternate motion to the slide-frame,
by which means the punches are with great facility adjusted in the dies i.
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BOILER PLATES.
a Shaft running through building.
b Crank.
c Connecting-rod.
d Upper lever worked by connecting-
395.
rod c.
B
Lower or punching lever engaged
or disengaged by means of rods,
levers, and pin é.
Punching-frame raised or depressed
I
9
by lever a and counterbalance
weight g.
Lever and counterbalance weight.
Punches.
e
i Die-frame.
j Self-acting rods, levers, and counter-
balance weight, for engaging and
disengaging notched bar from
0
7
stops r' r', worked by pin j.
m
k Notched bar fixed to table and
stopped by projecting stops k
alternately on either side for each
rivet.
I Handle, pinion, and rack, for ad-
vancing table by hand.
Moveable table for carrying plate
to be punched, drawn along by
rope or chain running over put
ley R.
Fixed tables supported by columns.
P Frame for carrying machinery.
396.
q Lever for raising punching-lever
when the punch is required to
be changed without stopping the
length of shaft.
the
n
m
m
8
l
397.
6
a
j Selfacting rods, levers, and counterbalance
a Shaft running through building.
b Crank.
weight, for engaging and disengaging
c Connecting-rod.
J
notched bar from stops r' r', worked by
pin
d Upper lever worked by connecting-rod c.
k Notched bar fixed to table and stopped by
e Lower or punching lever engaged or disen-
projecting stops k alternately on either
gaged by means of rods, levers, and pin é.
side for each rivet.
f
Punching-frame raised or depressed by lever
21
/ Handle, pinion, and rack, for advancing
e, and counterbalance weight g.
table by hand.
Lever and counterbalance weight.
m Moveable table for carrying plate to be
h Punches
&
Die-frame.
punched, drawn along by rope or chain
running over pulley n.
0
0
o
q
1
m
m
0-0
n
K
0
21
7
of
5
3
9.1
A
E
0
n Rope and pulley for drawing along
changed without stopping the
a moveable centre at s".
table m.
length of shaft.
t Bar for regulating the pitch of rivet-
Fixed table supported by columns.
Lever fixed at one end to rod j; on
holes, working between pins s' s';
P Frame for carrying machinery.
this lever is fixed two small pro-
it has a fixed centre at i. and
9
Lever for raising punching-lever
jecting pieces r'r'.
may be placed at any angle by
when the punch is required to be
Lever with two guide-pins having
sliding in groove t".
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BOILERS.
135
The jaws in the frame p are much strengthened by placing a square wrought-iron bar between them,
in places provided for the purpose.
From the above description, it will be seen that the advantages possessed by this machine, more
than compensate for the increased number of its parts, which are but few when compared with its
superiority over those of ordinary construction.
BOILERS. Varieties of, and circumstances attending their use and construction.
Before proceeding to give tabulated computations of the fire and flue surface of boilers, the per-
formance of the different varieties with respect to consumption of fuel, and such other particulars rel-
ative to their performance as will be a guide to the engineer, and show forth the best methods of
construction, we think it expedient to give drawings of some of the boilers of which these particulars
are to be determined, both to render our tabulated results clearer than they could otherwise be, and
to furnish the engineer with examples to avoid or imitate. These delineations are all made to a scale,
and on the more important of them the sizes are also marked; so that these wood-cuts may serve all
the purposes of working drawings-half an inch either in excess or defect in the length of a boiler
being a thing of no importance. Subjoined are given two scales, the one or the other of which is
No. 1.
Scale 3 inches = 11 feet.
No. 2.
Scale 3 inches = 16 feet.
applicable to such of the boilers rep=ented as are not measurable by any of the scales in common
use. A notification will be given of each case in which either of these scales is to be applied.
Fig. 398 is 3 transverse section of a 30-horse power wagon boiler of the kind employed by Messrs.
Boulton and Watt. This boiler will serve as a type of its class. We shall hereafter give the length,
breadth, height, and surface for the different powers
Figs. 399 and 400 represent a land boiler of a very good description constructed by Messrs. Caird &
Co. for a blast-engine of small size. This kind of boiler is common enough; but it has generally only
one tube for conducting the smoke through the boiler, instead of the number here represented.
Figs. 401 and 402 represent the boiler introduced by Messrs. Caird & Co. into some iron tug-boats made
by them. Cylinder, 32 inches in diameter-length of stroke, 3 ft. 6 inches. We shall not, in general,
append the size of the engines or the number of the boilers to the drawings, as all this information
will be given in a more commodious form in our tables.
398.
399.
400.
SCALE.-1-20th inch = 1 foot.
SCALE.-1-20th in. = 1 foot.
Longitudinal Section.
Transverse Section.
401.
402.
10
2
50
SCALE.-1-12th inch = 1 foot.
Transverse Section.
Figs. 403, 404, 405, and 406 are different views of the boilers of the steamer Phoenix, a steamer con-
structed by Messrs. Scott, Sinclair, & Co., for plying between Cape Town and Algoa Bay, at the Cape of
Good Hope. This vessel was provided with collecting vessels within the boiler for obviating the
deposition of scale; an expedient of much efficacy, and of which at the right place we shall furnish our
readers with full information.
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BOILERS.
405.
404.
403.
:
SCALE.-1-16th inch = 1 foot.
SCALE.-1-16th inch = 1 foot.
SCALE.-1-16th inch = 1 foot.
407.
406.
200
30
210
SCALE.-1-16th inch = 1 foot.
SCALE.-1-16th inch = 1 foot.
Longitudinal Section.
Elevation and Transverse Section.
Figs. 407, 408, and 409 represent the boilers of the Achilles steamer, constructed by Messrs. Caird &
Co. This vessel plies between Liverpool and Glasgow, and is well known for her numerous excel-
lencies.
409.
10
10"
"
408.
60
20
SCALE.-1-16th inch = 1 foot.
SCALE.-1-16th inch= 1 foot.
Longitudinal Section and Exterior.
Horizontal Sections and Bird's-Eye View.
Fig. 410 represents the boilers of the sister ship, the Eagle, also by the same makers. There is
nothing of peculiar excellence in these plans; and, for steam vessels, we believe boilers of this kind
will be superseded by the tubular plan of boiler, of which we shall give all the best specimens. But
a good number of boilers upon the common flue plan are still made, so that some specimens of them
are indispensable; and, indeed, there are still far more flue-boilers in use than there are of any other de-
scription. In most of these boilers it is a fault that the furnaces are made too long and narrow, and the
consequence is, that it is impossible to fire them on a long sea-voyage, especially in stormy weather.
It is much preferable to restrict the furnaces to a moderate length, and give the bars a considerable
clevation, so that they may always be well covered with coal at the after ends. When the furnaces are very
long, a good deal of air generally escapes into the flues at the after end of the bars, the effect of which
is materially to lessen the generation of steam.
Figs. 411, 412, and 413 represent the boilers of the Thames and Medway, two vessels of large size,
constructed by Messrs. Maudslay & Field for the Mail Steam Packet Company. The boilers of these
vessels have been very successful, and are among the best specimens of the flue-boiler as applicable to
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BOILERS.
137
410. marine engines hitherto produced. We do not know
411.
of any boiler of this kind that engineers may imi-
tate with greater safety, ás regards their power
of generating steam, though there are many speci-
mens distinguished by a greater durability. In
some of the boilers recently introduced in the Mail
Steamers, the furnaces stand athwartships, and the
plan is attended with the material advantage that
the coals trim more easily; for the coal reserve in
this arrangement situated behind the boilers, and
Scate.-3-20th inch 2 fect.-Elevation and Horizontal Section.
another depot standing between the boilers and the
t
engines, communicate immediately with the stoke-
holes, whereby an easy transfer of the coal becomes
accomplishable.
Figs. 414 and 415 are also views of the boilers of
Horizontal Section through
the Thames and Medway, These views are per-
Flues.
pendicular sections through the lines A B and C D,
shown in the horizontal section through the furnaces,
412.
and the horizontal section through the flues. The
dotted sweeps at the two upper corners represent
the ascent of the flue into the funnel. The flue
narrows in width and rises in height as it approaches
the chimney, for the same area is not required for
the transmission of the smoke after its volume has
been contracted by the communication of heat to
the water, and a less depth of water above the flue
suffices after the heat of the smoke traversing it
has been well-nigh expended. The bridges are
water bridges, and their superior ridges do not
run in a horizontal, but in an oblique direction, the
design of which is to facilitate the extrication of
the steam. There are four boilers in all, and the
Horizontal Section through
boilers are fired from both ends.
Furnaces.
In furnaces with two lengths of furnace-bars, it is a good plan to make the centre-bearer double, so
that the ends of the bars may have a space between them through which the ashes will be precipi-
tated; the space thus left enables the bars to expand without injury on the application of heat, whereas,
without some such provision, the bars are very liable to get burned out by their centres bending up into
the furnace, or else the lugs which carry the bearer-bars will be perpetually being carried away. A
similar space should be left between the fore end of the bars and the dead plate at the furnace mouth,
and care should be taken that not only the ends of the bars do not touch, but that the heels of the bars
do not rest against the furnace-bearers.
513.
514.
415.
Longitudinal Section.
Scals.-1-8th inch = 1 foot.
SCALE.-1-8th inch = 1 foot.
Section through A B.
Section through CD.
The bridges of these boilers are, it will be observed, of brick, and come tolerably close to the fur-
nace top. In such cases it is expedient to make the upper part of the bridge consist of one or two fire-
brick blocks, which may be lifted off when a person requires to enter the flues to sweep or repair them.
The continual knocking down and building up of bridges becomes otherwise very expensive. In boilers
of this construction it is difficult to light one tier of fires after the others have been thoroughly kindled,
as the fires first lighted keep the lead in the draught. It might be anticipated that by firing the tiers
of fires alternately, the smoke would be burned, but such is not found to be the effect.
18
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138
BOILERS.
Provision has been made in these boilers for the introduction of a fan-blast, which would at once
cure the evil of a defective draught. The furnaces would, in this plan, be made close, and the blast would
be introduced into a chamber at the back of the ashpit A, Fig. 418, from whence it would pass into the
ashpits by necks A A A, Fig. 416. One inconvenience, however, of a fan-blast thus applied is, that the
smoke comes out of the furnace-doors very much when they are opened.
Almost every engineer has made tubular boilers that were short of steam, but we never before met
with one who acknowledged it.
The original boilers of the Great Western contained of flue surface 2950 square feet, and of furnace
surface 890 square feet, making 3840 square feet of heating surface; area of fire-grate 202 square
(eet; capacity of steam-room 1150 cubic feet weight of boilers and steam-pipes 202 tons weight of
water 80 tons; average consumption of coal 1000 tons per voyage, out and home, of 27 or 28 days.
In the tubular boilers, Figs. 416 to 418, the tube surface is 5900 square feet, smoke-box surface 830
square feet; furnaces 420 square feet; making 7150 square feet of heating surface; area of fire-grate
145 square feet weight of boilers 56 tons; weight of water 52 tons capacity of steam-room 1320
cubic feet average consumption of coal per voyage out and home, of 29 days, 696 tons. The speed of
the vessel, it will be observed, has somewhat declined with the new boilers, but there is a greater econ-
omy in fuel upon the same distance. The horse power of the Great Western is about 400; the par-
ticulars of the two boilers will therefore stand as follows :-
Old Boiler.
New Boiler.
Heating surface per horse power
96
17875
Fire-grate per horse power
5
3625
Steam-room per horse power
2.875
33
Coal per hour per horse power
8-333
5.6
The consumption of fuel, as here set down, it must be borne in mind is that of the old beiler in its super-
annuated state, and of the new boiler in its best state. The old boiler, when new, did not consume
more than 6 lbs. of coal per horse power per hour.
The tubes of these tubular boilers are of iron of 3 inches internal diameter, and 8 feet in length.
The furnaces are 8 feet 3 inches in length, which is, in our judgment, a greater length than can be fired
effectually on so long a voyage as the Great Western has to perform. The water within the boiler
rises some distance above the top tubes. It would be better, we think, to let the return tubes go through
the steam, which would dry it very effectually, and surcharge it in some degree with heat. This could
easily be done by lowering the water-level, and the hot air will be sufficiently cooled, after passing
through the lower tier of tubes, to prevent any injury to the upper tier from an excess of heat. One of
the advantages of iron tubes is, that they can be subjected to a degree of heat, with impunity, that
would be unsafe to apply in the case of brass tubes. It is said, however, that the scale adheres to
them with greater tenacity than to brass, but this objection is not likely to prove of much weight if the
boilers be well blown out, for in that case very little scale will be formed at all.
Figs. 419 and 420 represent the boilers of the British Queen steamer, constructed to ply between
London and New York. There is nothing very peculiar in this kind of boiler; and, indeed, it is nothing
more than the common marine boiler, as used for the ordinary coasting vessels, constructed upon a larger
scale. There are four boilers in the vessel, ranging athwartships, containing in all fourteen furnaces,
the wing boilers containing four furnaces each, and the midship boilers three furnaces each. The pro-
jection of the water-space into the flues at the after-end of the wing boiler is to obviate a back-draught
in the furnaces, in cousequence of the currents of hot air meeting one another in a direct antagonism at
the point where they coalesce, and which they would do but for this protuberance, which deflects each
of them sufficiently to make it enter, without conflict, the longitudinal flue. These boilers were kept
supplied with fresh water, as the engines are fitted with Hall's condensers, which return the condensed
steam to the boiler to maintain the water-level This species of condenser is now discontinued in most
vessels, as its weight and expense are formidable objections, and it does not act as a preservative of the
iron of the boiler from corrosion. One government vessel, some time since, fitted with Hall's condenser,
had no less than 22 miles of copper pipe for accomplishing the condensation of the steam. The use
of salt water in boilers is attended with very little inconvenience if they be often blown out, and their
durability is little, if at all, increased by the employment of fresh water.
Figs. 421 and 422 represent the boilers of the City of London steamer, a vessel lately con-
structed by Mr. Napier, of Glasgow, to ply between Aberdeen and London. These boilers are much
upon the plan of the boilers of the Thames and Medway, and are fired from both ends instead of from
one end, as in the boilers of the British Queen. There is a hanging water-bridge, it will be observed,
at the end of the furnace, Fig. 421, beneath which the flame has to descend before it can enter the flues.
This arrangement we look upon as very judicious. The hot air, by virtue of its specific levity, ascends
into the upper part of the furnace-chamber, where it remains until it has given out a considerable por-
tion of its heat, and it is only after its specific gravity has been increased by the extraction of heat that
it can overflow into the flues. It is also a good practice to place a hanging bridge of sheet-iron at the
after-end of the flue, where it enters the chimney.
Figs. 423, 424, and 425, represent the original boilers of the steamer Tagus, constructed by Messrs.
Scott, Sinclair & Co. The following are some of the dimensions of the original boilers :-Length 24
feet 3 inches, height 10 feet; breadth of each boiler 7 feet 6 inches, making the total breadth of the
boilers about 22 feet 8 inches, with projections of rivet-heads. Length of under furnaces 8 feet; length
of upper furnaces 7 feet 6 inches. Breadth of furnaces 3 feet; total number of turnaces 12. Each
boiler contains 14 iron pipes of about 10 inches in diameter, and 10 feet in length, through which the
smoke passes on its way to the chimney. These pipes are formed of boiler-plate, with turned rings or
collars attached to each end, which are inserted into holes in the smoke-box plates, and then riveted
over. These rivets are liable to get burned away by the action of the flame, as the collars within pre-
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BOILERS.
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416.
:
417.
18 feet 6 inches.
SCALE.-9-122th inch = ) foot.
- 24 feet. - A-A-A-
a. Horizontal Section through Furnaces.
SCALE.-0-198th inch = 1 foot,
b. Horizontal Section above Furnaces.
Transverse Section.
c. Horizontal Section above Tubes.
418.
420.
410
A
a
-
12 feet.
SCALE.-9-128th inch = 1 foot.
Longitudinal Section.
421.
e
Scale.--075 inch = 1 foot.
Horizonal Section.
Perpendicular Section.
Longitudinal Section.
423.
422.
10 feet.
0000000
7 feet 6 in.
7 feet 6 in.
SCALE.-075 inch = 1 foot.
SCALE.-9-128th inch = I foot.
Through Flues. Horizontal Section. Through Furnaces.
Transverse Section. Elevation.
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BOILERS.
vent the water from getting access to the angle, and the plates into which they are fixed then get
pressed out by the force of the steam. It would be a good plan to cover these rivets with another
perforated plate placed above them, the holes in which should be of a somewhat smaller diameter than
that of the tubes.
Figs. 426, 427, 428, and 429, represent a marine boiler with upright tubes, a kind of boiler to which
we have already made several allusions, and which we are persuaded will, before long, come into ex-
tensive use. This boiler, it will be remarked, has the water outside of the tubes, and the upper portion
of the tubes does not pass through the water, but only through the steam, by which the steam is thor-
oughly dried, and any inconvenience from priming counteracted. We have another specimen of this
boiler to give, and shall reserve what we have to say about the plan until we come to it.
Figs. 430, 431, 432, 433, 434, and 435, represent the boilers of the Queen steamer, a river vessel, con-
structed by Messrs. Rennie, and well known for her swiftness and efficiency. The object this boiler
424.
425.
10 feet.
3ft.
3 ft.
2.
24 feet 3 inches.
24 feet 3 inches.
SCALE.-9-198th inch = 1 foot.
SCALE.-9-128th inch = 1 foot.
Longitudinal Section.
Horizontal Section.
426.
427.
428.
429.
60
Section through Ashpit, showing
Section through Tubes.
stays of bottom water space.
430.
431.
52
R
SCALE.-1-8th inch = 1 foot. No. 1.
E/
vation.
Perpendicular Section.
SCALE.-1-16th inch = 1 foot.
Transverse Section.
Elevation.
434.
435.
432.
433.
SCALE.-1-16th inch = 1 foot.
SCALE.-1-16th inch = 1 foot.
Longitudinal Section.
Elevation.
Plan.
Horizontal Section.
seeks to attain is lightness, and it is therefore made so as to hold very little water. It does not, how-
ever, appear to be well calculated to sustain any considerable pressure, though this is an object of im-
portance in vessels intended to go fast. The following are some of the principal dimensions -Length
13' 8"; breadth 12' 8"; height 6' 0"; length of furnaces 5' 2"; length of tubes 5'7"; breadth of fur-
naces 2' 8"; diameter of tubes 2' 6"; material of tubes brass. Total number of tubes 228. Diameter
of cylinder of engines 29'3"; length of stroke 4' 6". There are two engines on the direct action plan.
Collective power 76 horses.
If any considerable pressure of steam he employed in this boiler, it will be necessary to stay down
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BOILERS.
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the boiler-top very firmly, both to the tops of the furnaces and the bottom of the boiler; for the force
acting against the boiler-top, and tending to raise it upwards, will be immense, if a high pressure be
adopted. To stay the boiler-top to the tops of the furnaces alone would not be sufficient, for the tops
of the furnaces might alter their form, and the stays would then be of very little avail. The stays to
the bottom of the boiler, however, if carried in the usual way, would have to be attached to the bottoms
of the water spaces, and there they would be much in the way when the boilers are being cleaned.
Indeed, it would be almost impossible to clean out the water legs effectually with stays so situated,
and the best method, therefore, appears to be either to stay the boiler-top to a strong inverted arch
spanning the water spaces, or to place a succession of iron arches over the furnace tops, to keep them
in shape, after the fashion practised in Stephenson's locomotives, and to stay the boiler-top to these.
Figs. 436 and 437 represent another boiler with upright tubes, (having the wa-
436.
ter outside of them,) the design of Messrs. Rennie. This boiler is intended to
supply steam to an engine on land, and its exterior is therefore composed of a cyl-
inder of brickwork, between which and the boiler-shell the smoke is made to cir-
culate on its way to the chimney. This brick cylinder is surmounted by a cast-
iron dome, the edge of which fits into a groove containing sand, and access can
readily be had to the ends of the tubes by raising up this dome by the tackle ap-
plied to the eye fixed in its centre. This kind of boiler is identical in all its im-
portant features with that represented in Figs. 426, 427, 428, and 429. That
boiler, however, is intended for a steam vessel, and is, indeed, the boiler of one of
the tug vessels working upon the Thames. As we happen to have a very high
opinion of this variety of boiler, we must consider its merits in some detail, and
therefore refer back our readers to Figs. 426, 427, 428, and 429, as it is to that
specimen our remarks chiefly apply.
The diameter of that boiler is 6 feet; height, 11 feet 6 inches; diameter of fire-
box, 5 feet 2 inches distance from top of bars to lower tube-plate, 1 foot 6 inches
distance from top of bars to ashpit bottom, 1 foot 7 inches length of tubes, 8 feet
SCALE.-1-8th inch=1 ft.
Perpendicular Section.
diameter of tubes, 2 inches; distance from centre to centre of tubes, 3 inches; di-
ameter of tube-plate, 3 feet 10 inches. There is a clear space of 1 foot 2 inches all
437.
round, between the tubes and the boiler-shell. The height to which the water
rises along the tubes is 5 feet, leaving 3 feet of the tubes to traverse the steam
space. There are 145 tubes in all, and, reckoning their effective length at 5 feet,
the effective tube surface is 881.53 feet. The fire-box surface is 20.96 feet, ma-
king a total of 412.03 square feet of effective heating surface. The area of the fire-
grate is 20.96, and the proportion of fire to heating surface is 1 to 20 nearly.
One of these boilers supplies the engine of the vessel with steam, the cylinder of
which is 26 inches in diameter, and the length of stroke 38 inches, the number of SCALE.-1-8th inch=1 ft.
strokes per minute, 35 light, 26 to 30 when towing. The consumption of fuel is
a a Furnace Doors.
10 cwt. of coal per four hours, including getting up steam. The tubes are of iron,
Transverse Section.
and show no symptoms of injury from the application of heat above the water-level. In some of the boilers
constructed on this plan the lower tube-plate has cracked between the tubes, andwe think the breadth of
an inch of iron between the tubes is insufficient in most cases. It would be an improvement, we think,
to zigzag the tubes, which would leave more iron between the tubes, and, at the same time, would not
prevent the introduction of an instrument to scrape them when necessary, at least diagonally. It would
be very expedient, too, to defend the tube-plate from the heat of the fire by a fire-brick dome perfo-
rated opposite to each tube. In that case, however, it would be necessary to give an additional tube
surface, as more heat would then pass into the tubes than if such a dome were not employed. It is one
drawback to the merits of this boiler, that it will be liable, we fear, to corrode internally more rapidly
than common boilers. One of the most influential causes of internal corrosion appears to be the exist-
ence of surcharged steam within the boiler, and in this kind of boiler the steam is almost necessarily
surcharged to some extent. The surcharging, however, will be less considerable if there be a large
heating surface, which may easily be given. It will be necessary in applying boilers of this construc-
tion to steam vessels to adopt means of blowing out the supersalted water very effectually, else the
scales may fall from the tubes upon the tube-plate, and occasion injury.
One very obvious objection to this plan of boiler will present itself to our practical readers, which is,
that a deposite either of silt or scale will be liable to take place on the top of the tube-plate, which
will, in consequence, very soon burn out. This evil is to a great extent met by our suggestion to inter-
pose a firebrick dome between the tube-plate and the fire; but we have not been able to discover that
any sensible inconvenience has arisen from such depositures in boilers of this construction, even without
the expedient we have just described. The agitation of the water, caused by the ascent of the steam
up through it, is a powerful antidote to any settlement where it is going on, and the particles of matter
mingled with the water, and out of which scale is fabricated, find their way by degrees to the sides of
the boiler, where the water is tranquil, and there they finally settle. It is expedient, however, in boil-
ers of this kind, either to blow off very frequently, or to have brine-pumps, which change the water in
the boiler rather faster than usual. It would be a further improvement to place a collecting vessel
within each boiler. Instruments of this kind have hitherto been very little used in steam vessels, but
in land boilers they have long been employed with advantage, though in that case the advantage is of
less account. We shall at a more advanced stage of our progress give some specimens of collecting
vessels as applicable to marine boilers, but may here, for the sake of making our recommendation in-
telligible, explain the simplest form of collecting vessel as applied to wagon boilers.
We must first, however, premise that the addition of particles of extraneous matter to boiling water
facilitates the extrication of the steam, and, in many cases, lowers the temperature at which ebullition
carried on. The generation of steam is most active in those situations where those particles exist,
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BOILERS.
80 that, indeed, the steam appears as if it came out of them, and the particles are continually buoyed
up by the steam in its ascent, and prevented from settling where the ebullition is active. If a vessel
with a narrow mouth be immerged in a boiler under such circumstances as to preserve the water within
it in a tranquil state, the vessel will speedily become filled with depositure resembling mortar, which,
could it have settled, would have been indurated into scale. Of this circumstance advantage is taken
in the construction of collecting vessels, for if the whole of the water in a boiler be in a state of ebulli-
tion except a portion contained in an internal vessel, into that vessel the depositure will find its way
and from thence it may be removed by blowing out.
The remarks which we have already made respecting this species of boiler are sufficient, we con
ceive, to show that the objections which might be brought against it are not of an insuperable character
Its recommendations, however, are not of a negative kind, and it possesses two of weight enough, we
conceive, to entitle it to a preference over most kinds bitherto projected. The first is, that if the steam
be taken off by a perforated pipe there will be but little priming; and the second, that the construction
facilitates the introduction of the revolving grate, and which, we anticipate, will come into general use
for steam vessels. There is nothing in the revolving grate too complicated for such an application
and it would be a matter of great importance to have the furnaces of steam vessels feeding themselves,
which they would do much more effectually, and much more cheaply, than can be done by hand
Boilers on this upright plan might be arranged across the vessel thus:
Ship's side.
Ship's side.
with a crucial passage between them, and the athwartship passage need only be of a width cufficient
to enable the attendants to light and clean the fires. We cannot here enter into the details of the ap-
plication, but may remark that in those cases in which it may be inconvenient to drop the coal upon the
fire through a slit from the top of the boiler, it will probably be found the best way to combine the boil-
ers, so that one revolving grate will suffice for two sets of tubes, and the coals may then be introduced
between the tube cylinders, and immediately
over the fire. One material advantage of this
438.
439.
arrangement is, that there will be no smoke-a
virtue often claimed for the Cornish plan of
boiler, but without any title thereto, farther than
what arises from slow combustion and the use
of Welsh coal, and both of these points may
be attained in any boiler.
Figs. 438 and 439 represent a small tubular
boiler constructed by Messrs. Horton & Son for a
coasting steamer called the Zephyr. This boil-
er has been found to perform well, and is, in
every respect, satisfactory. The tubes are of
iron, 3 inches in diameter, and 6 feet long.
Length of furnace 6 feet, number of tubes 168.
2 engines. Consumption of coal per hour, about
SCALE.-1-10th inch=1 foot.
SCALE-1-10th inch=1 foot.
6 cwt. The pressure of steam is about 5 lbs.
Front View and Transverse Section.
Longitudinal Section.
on the square inch.
Figs. 440, 441, and 442, represent another boiler, by Messrs. Miller, Ravenhill & Co., of the tubular
kind. It is identical in all its main features with the boilers of the Tagus, already described, and the
same remarks apply to it. It has been found expedient to introduce a jet of steam into the chimney
of this vessel to quicken the draught. The tubes are of brass, 34 inches in diameter, and the tube-
plates are of iron. A galvanic action between the brass and the iron has been found to arise in some
boilers, which shows itself, not at the ends of the tubes, but at the ends of the athwartship stays which
bind the sides of the boiler together and the iron plate around these stays very soon acquires the ap-
pearance of having been scooped out by a knife; but in other boilers no action of this kind has been
found to take place, and it has been doubted whether a leakage caused by the inadequate fastening of
the stays has not had something to do with its production; nevertheless, in several cases of brass-tubed
boilers which have come under our observation, the action has been very remarkable in the situation we
have mentioned. The evil would probably be obviated by the application of a washer of zinc. Ex-
perience in the use of tubular boilers certainly shows that brass tubes are on the whole the most eligi-
ble. Iron tubes are speedily eaten into holes by corrosion, and it is remarkable that the corrosion chiefly
takes place upon the under side. Brass tubes, on the contrary, are found to last many years. It ap-
pears to be the best plan to refrain from attempts at scaling brass tubes, but they may be withdrawn
once a year, cleaned, and reinserted.
Figs. 443, 444, and 445, represent the boilers of the steam vessel Ocean. The tubes of these boilers
are of iron 31 inches in diameter and 9 feet long furnaces 7 feet long and 2' 1" wide. There are three
boilers in all the centre one with three furnaces, and the two wing ones with two furnaces each. Total
breadth of boilers 19} feet; total length 14 feet; total number of tubes 378; two engines-diameter
of cylinder 56 inches; length of stroke 51 feet; pressure of steam about 4} lbs.; consumption of coal
about 18 cwt. per hour. In ordinary coasting vessels we do not approve of the plan of firing from each
end, as the length in the vessel occupied by an additional firing space is a manifest waste of room; and
there will be no difficulty in short voyages. about maintaining the trim of the ship on account of the
stowage of so evanescent a cargo as coal in the wake of the furnaces. The object should, we conceive,
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be to obtain the requisite number of furnaces in the breadth of the ship, and then to add a sufficient
number of tubes above the furnaces to extract the heat given out in them. In cases where this cannot
be altogether, and yet can be nearly done, it is a less evil, we conceive, to put a few furnaces in a sec-
ond tier into the midship boiler, rather than change the whole plan of the boiler by firing from both
ends. In most cases we believe it will be possible to get sufficient room for the furnaces in the breadth
of the ship if the engines be wrought expansively ; and this may be done, without affecting the power,
either by applying high-pressure steam to the existing size of cylinders, or by introducing larger cylin-
ders, and retaining the steam at a moderate pressure-that is, under 10 lbs. The latter plan in the case
440.
441.
442.
11 feet.
SCALE.-3-20th Inch = 1 foot.
SCALE.-3-20th inch = 1 foot.
SCALE.-3-20th inch = 1 foot.
Front View one-half in Section.
Back View one-half in Section.
Perpendicular Section.
of new vessels is, in our judgment, greatly the preferable one; and we should recommend all new steam
vessels to be made with the cylinders very large, while the boilers remain of the same dimensions as at
present, except in the case of vessels impelled by the screw, where the engines may be worked at a very
high speed-an increase in the speed being equivalent to an enlargement of the cylinder. A great force
is thus available for the propulsion of the vessel when necessary, whether from adverse circumstances
of wind and water, or otherwise, merely by diminishing the degree of expansion; while, in fair winds
and smooth water, it becomes necessary to work with a very high measure of expansion to keep the
engines supplied with steam, thus securing a moderate and uniform consumption. To make the engines
light, while the power is kept undiminished, they must be worked with a fast piston; and to make the
boilers light, with unimpaired efficacy, they must be provided with an artificial draught, unless the calo-
rimeter or sectional area of flue be made larger than is at present usual in boilers forced in the manner
of locomotive boilers. It is doubtful whether the tubes of tubular boilers intended for low-pressure en-
gines are not still made longer than is expedient.
444.
445.
443.
SCALE.-3-29th inch = 1 foot.
SCALE.-3-28th inch = 1 foot.
SCALE.-3-28th inch = 1 foot.
Longitudinal Section.
Horizontal Section through Tubes of Wing
Transverse Section.
Bollers and Furnaces of Centre Boller.
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BOILERS.
Figs. 446, 447, and 448, are different views of the boilers of the steamer Forth, belonging to
the English Mail Steam-Packet Company. These boilers are well worthy of the attention of the
engineer, as they have approved themselves more economical than any of the other boilers employed
in those vessels, at the same time that there is an abundance of steam, and the speed of the vessel
is well maintained. The following are some of the more important particulars: There are four
447.
446.
SCALE.-1-11th inch = 1 foot.
SCALE.-1-11th inch = 1 foot.
Longitudinal Sections.
Transverse Section.
Front View.
448.
449-
9/10"
2.0"
6484
181
816
NB2
95
16
9.26
SCALE.-1-11th inch = 1 foot.
SCALE.-1-11th inch = 1 foot.
Horizontal Section through Furnaces. Horizontal Section through Flues.
Transverse Section.
Elevation.
451.
450.
46
"
8
SCALE.-1-11th inch = 1 foot.
SCALE.-1-11th inch = 1 foot.
Horizon Section through Horizontal Section through
Transverse Sections.
Furnaces.
Flues.
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boilers, with three furnaces in each, making 12 furnaces in all. Length of each boiler, 13' 6" breadth,
9' 10"; height, 14' 11". There is a fore-and-aft passage between the boilers, 2 feet wide, and an
athwart passage 18 inches wide. Length of furnace, 7' 4"; breadth of furnace, 313 inches; diameter.
of chimney, 67 inches; height of flues, 5 feet.
Figs. 449, 450, and 451, represent two sets of boilers constructed by Messrs. Bury, Curtis &
Kennedy, for the two steam vessels Wladimir and Der Greuss Adler, the one belonging to the Russian
and the other to the Prussian government, and both of the power of 320 horses. These examples
are of much interest, apart from all consideration of the general success of the constructors, the
boilers for the Russian vessel being of the tubular variety, while those for the Prussian vessel are on
the common flue plan; and we shall thus have a fair comparison of the merits of the two varieties.
The shape and dimensions of the tubular boiler are shown in the figures by means of dotted lines; and
a just conception may thus be arrived at of the amount of space occupied by a tubular and a flue boiler
of the same efficacy in raising steam. The tubular boiler, of which the outline is here given, is almost
identical with the boiler of the Braganza steamer, already given, and it is therefore needless here to
repeat the delineation.
Figs. 452, 453, and 454, represent the boilers of the Retribution, a steamer of 800-horse power;
the engines being on the double cylinder plan of Messrs. Maudslay. There is nothing very pe-
452.
453.
SCALE.-1-8th inch = 1 foot.
SCALE.-1-8th inch= 1 foot.
a. Horizontal Section through Furnaces.
a. Side View.
b. Horizontal Section through Flues.
b. Longitudinal Section.
enliar in these boilers except their size; in other respects they very much resemble the boilers
of the Great Western, and of the Thames and Medway, also by Messrs. Maudslay and Field, of which
we have already given delineations. Figs. 455, 456, 457, 458, 459, and 460, are different views of
a sediment-collector, as made by Mr. Armstrong, of Manchester, for marine boilers. The manner in
which this contrivance acts has already been explained, and all that we have here to do, is to give such
forms of the machine as have been found the most convenient in practice. The sediment-vessell are
generally made of thin sheet-iron, and an agitator with a handle extending through a stuffing-box to
the outside of the boller, is usually added to facilitate the blowing out of the silt and other foreign
matters caught by the collectors. In the manu-
454.
facturing districts, the main purpose for which
collecting-vessels are employed is the prevention
of priming.
Priming arises from insufficient steam room, an
inadequate area of water-level, or the use of dirty
water in the boiler the last of these instigations
may be remedied by the use of collecting ves-
sels, but the other defects are only to be correct-
ed either by a suitable enlargement of the boiler,
or by increasing the pressure and working more
expansively. Closing the throttle-valves of an
engine partially will generally diminish the
amount of priming, and opening the safety-valve
suddenly will generally set it astir. A steam
vessel coming from salt into fresh water is much
SCALE.-1-8th inch = 1 foot.
SCALE.-1-Sth inch = 1 foot.
more liable to prime than if she had remained
Transverse Section.
Elevation
19
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BOILERS.
in salt water, or never ventured out of fresh. This is to be accounted for by the higher heat at
which salt water boils, so that casting fresh water among it is in some measure like casting water
among molten metal, and the priming is in this case the effect of the rapid production of steam. One
of the best palliatives of priming appears to be the interposition of a perforated plate between the
steam space and the water. The water appears to be broken up by dashing against a plate of this
description, and the steam is liberated from its embrace. In cases in which an addition is made to a
boiler or steam-chest, it will be the best way not to cut out a large hole in the boiler-shell for establish-
ing a communication with the new chamber, but to bore a number of small holes for this purpose, so as
to form a kind of sieve, through which a rush of water cannot ascend. In locomotives the same end
is attained by the use of a perforated steam-pipe extending from end to end of the boiler. Such a
contrivance draws the steam off equally from the surface, instead of taking it from any one part; and
boilers provided with it are enabled to work with SO small a steam-space that the steam-domes are now
being taken away from locomotives altogether. This expedient has not yet been adopted in steam
vessels, though it appears to be applicable to them also with advantage. In some boilers priming
appears to be mainly caused by a malformation which prevents the water from circulating freely, and
the steam has therefore to pass up through the water, occasioning a great agitation, instead of the
water being enabled to circulate with the ascending steam. The evil may be mitigated in such cases
by the addition of pipes to the exterior of the boiler, which will permit a descending current to be
established, to replace the water carried upward by the steam.
455.
SCALE.-11 inch = I foot.
Front View of Bollers.
456.
SCALE.-11 inch = 1 foot.
Longitudinal Section of Boilers.
We cannot afford to surrender any more space to these specimens of boilers, and must now proceed
to dispatch what we have still to say on the subject of boilers in as few words as possible. We have
already stated that a cubic foot of water raised into steam is reckoned equivalent to a horse power,
and that to generate the steam with sufficient rapidity, an allowance of one square foot of fire-bars,
and one square yard of effective heating surface, are very commonly made in practice, at least in land
engines. These proportions, however, greatly vary in different cases; and in some of the best marine
engine boilers, where the area of fire-grate is restricted by the breadth of the vessel, and the impossi-
bility of firing long furnaces effectually at sea, half a square foot of fire-grate per horse power is a very
common proportion. Ten cubic feet of water in the boiler per horse power, and ten cubic feet of steam-
room per horse power, have been assigned as the average proportion of these elements; but the fact is,
no general rule can be formed upon the subject, for the proportions which would be suitable for a wagon-
boiler would be inapplicable to a tubular-boiler, whether marine or locomotive; and good examples
will in such cases be found a safer guide than rules, which must often give a false result. A capacity
of three cubic feet per horse power is a common enough proportion of furnace-room, and it is a good
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'plan to make the furnaces of a considerable width, as they can then be fired more effectually, and do
not produce so much smoke as if they are made narrow. As regards the question of draught, there is a
great difference of opinion among engineers upon the subject, some preferring a very slow draught, and
others a rapid one. It is obvious that the question of draught is virtually that of the area of fire-grate,
or of the quantity of fuel consumed upon a given area of grate-surface, and the weight of fuel burned
on a foot of fire-grate per hour varies in different cases in practice from 31 to 80 lbs. Upon the quick-
ness of the draught again hinges the question of the proper thickness of the stratum of incandescent fuel
upon the grate; for if the draught be very strong, and the fire at the same time be thin, a great deal of
uncombined oxygen will escape up through the fire, and a needless refrigeration of the contents of the
flues will be thereby occasioned whereas, if the fire be thick, and the draught be sluggish, much of the
useful effect of the coal will be lost by the formation of carbonic oxide. The length of the circuit made
by the smoke varies in almost every boiler, and the same may be said of the area of the flue in its
cross-section, through which the smoke has to pass. As an average, about one-fifth of the area of-fire-
grate for the area of the flue behind the bridge, diminished to half that amount for the area of the
chimney, has been given as a good proportion, but the examples which we have given, and the average
flue-area of the boilers which we shall describe, may be taken as a safer guide than any such loose
statements. When the flue is too long, or its sectional area is insufficient, the draught becomes insufficient
to furnish the requisite quantity of steam whereas if the flue be too short or too large in its area, a
large quantity of the heat escapes up the chimney, and a deposition of soot in the flues also takes
place. This last fault is one of material consequence in the case of tubular boilers consuming bitumin-
ous coal, though, indeed, the evil might be remedied by blocking some of the tubes up. The area of
water-level is usually about 5 feet per horse power in land boilers. In many caser, however, it
is much less; but it is always desirable to make the area of the water-level as large as possible,
as when it is contracted, not only is the water-level subject to sudden and dangerous fluctuations,
but water is almost sure to be carried into the cylinder with the steam, in consequence of the
violent agitation of the water, caused by the ascent of a large volume of steam through a small
superficies. It would be an improvement in boilers, we think, to place over each furnace an in-
457.
SCALE.-3-16th inch = 1 foot.
Horizontal Section and Bird's-eye View.
458.
459.
460.
AAD
Plan of Collecting Vessel from Bottom.
Plan of Collecting Vessel from top.
Plan of upper Collecting Vessel
verted vessel immerged in the water, which might catch the steam in its ascent, and deliver it quietly
by a pipe rising above the water-level. The water-level would thus be preserved from any inconve-
nient agitation, and the weight of water within the boiler would be diminished at the same time that
the original depth of water over the furnaces was preserved. It would also be an improvement to make
the sides of the furnaces of marine boilers sloping, instead of vertical, as is the common practice, for
the steam could then ascend freely at the instant of its formation, instead of being entangled among the
rivets and landings of the plates, and superinducing an overheating of the plates by preventing a free
access of the water to the metal.
In the Transactions of the Institution of Civil Engineers, several papers are given by Mr. Parkes and
others, descriptive of experiments made by them on steam boilers. We have, in Table 1, collected a
few of the principal results exhibited in Mr. Parkes' very voluminous tables, and we have added the
two columns on the right-hand side of the table, to show at the same time the evaporative economy of
the boilers in use at the East London Water Works. One of these boilers is on the Cornish plan, and
attached to the Cornish engine there. The other is a wagon boiler, with an internal flue, for supplying
steam to a Boulton and Watt pumping-engine. The Cornish boilers are cylindrical, with an internal
flue; and, as they are generally used with steam of from 15 lbs. to 35 lbs. above the atmosphere, they
are made of plates half an inch thick. The left-hand column in the table gives the mean results of ex-
periments made on the boilers at the Huel, Towan, and United Mines in Cornwall. The second column
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BOILERS.
from the left is devoted to Mr. Parkes' experiments at Warwick; and, according to him, about one-sixth
of the evaporation there given is due to his smoke-consuming apparatus. The third column exhibits
the mean of eight experiments on wagon boilers, at the different places indicated at the head of the
column, which were all (except the Albion Mills experiments) conducted by Mr. Parkes. The fourth
column from the left contains the results of Mr. Smeaton's experiments on his atmospheric engine at
Long Benton; and the fifth column gives the mean of eleven experiments on locomotives by M. de Pam-
bour. Referring to the sixth line, it will be seen that the mean evaporative economy of the Cornish
boilers is about the same as that of the Warwick boilers; but, if we exclude the East London Water
Works boiler, the other Cornish boilers will show a decided superiority over all the rest. Lines five
and eight show two of the principal peculiarities in the proportions of the Cornish boilers. It will be
observed that the extent of their surface exposed to the heat, for each cubic foot of water evaporated,
is about seven times as great as in any of the others. The combustion in their furnaces also is carried
on at a very slow rate, there being only about 31 lbs. of coals burned on each square foot of grate. The
only boiler that makes any approach to them in slowness of combustion is the one at Warwick. Mr.
Parkes is a great advocate for slow combustion; and he founds his opinions principally on its effect in
the Warwick boilers-at least it is from his experiments on them that he derives his opinion, that the
principle should be carried so far as it was in that case. We conceive that in this instance he has over-
looked one very material circumstance. It will be observed in the table, that the heated surface bears
very nearly the same proportion to the water evaporated in these boilers as in the other wagon boilers;
but, before Mr. Parkes altered his furnaces, much more water was evaporated per boiler, and, conse-
quently, the heating-surface must then have been very small in proportion to the evaporation. We
are, therefore, rather inclined to attribute the increased duty of the fuel to the increase of the heating-
surface of the boiler, than to the diminution of the rate of combustion. Nevertheless, from other ex-
461.
SCALE.-2th inch = 1 foot.
Longitudinal Section and Elevation of Collectors.
periments of Mr. Parkes, we are disposed to think that, for economy of fuel, the combustion in the gen- -
erality of wagon-boiler furnaces is rather too rapid. The very large proportion that the heating-surface
in the Cornish boilers bears to the weight of water evaporated, is, no doubt, to a considerable extent,
rendered necessary by the thickness of the plates which the heat has to penetrate, and the high tem-
perature of the water within them-both circumstances that retard the transmission of the heat. The
Cornish practice, too, is universally, 80 far as we have been able to ascertain, in favor of this great ex-
tent of surface; yet we can hardly think that a small diminution of it would produce any injurious
effect on the economical properties of the boiler, while it would save a considerable part of the original
cost.
It will be seen, from what we have already advanced, that but a small part of the superior duty of
the Cornish engines can be derived from the boilers; we must therefore look to the engines for the
principal sources of their superiority, which may be comprised under these three heads:-
1st. The use of high-pressure steam cut off when a very small part of the stroke has been performed,
and working expansively over the remainder.
2d. The careful clothing of every part of the engine where heat can escape. The cylinder is usually
encased with a steam-jacket; and the steam-jacket itself, and all the steam-pipes, top of the boiler, &c,
are protected from the cold air by being covered with a layer of three or four inches thick of ashes,
saw-dust, or other good non-conductor of heat. The amount of saving effected in this way may be
conceived to be very considerable. We have not met with any experiments to ascertain the amount
of the saving by clothing the whole engine; but Mr. Wicksteed found that clothing the top of the
boilers alone produced a saving of 101 per cent. in the fuel consumed.
3d. The third main source of the great duty of the Cornish engines is to be found in the excellent
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system of registering and publishing the duty of each engine, which has for many years been prevalent
in Cornwall. It has made both the proprietors and engineers much more careful than they otherwise
would have been of a host of details that have elsewhere been considered too trifling to require notice;
but which, nevertheless, in the aggrégate, are of no small importance.
TABLE L
Mean of Huel, Towan, and
United Mines boilers, in
Cornwall.
Mr. Parkes' boiler, at War-
Mean of 8 experiments at
the Albion Mills, Clithero,
Preston, and New River
Water Com., of London.
Atmospheric
Smeaton's
Engine, at Long Benton,
Noneumberland, 1778.
of of M. Pambour's
experiments on the Loco-
motives of the Liverpool
and Manchester Railway.
wick.
Cornish boiler at East Lou-
don Water Works, 1839.
Boulton and Watt boiler
the Ban London Water
Works, 1839.
Cylindri-
Circular
Cylindri.
Wagon
Nature of the Bollers used.
cal with
Locomo-
internal
Wagon.
Wagon.
or Hay-
cal with
with in-
stack.
Live
internal
termal
flue.
flue.
flue.
Total area of heated surface in square feet
962
152
342.8
459
334.6
798
588
Length of circuit made by the heat in feet
155
50.66
72.5
52.8
7.0
83.1
78
Area of fire-grates in iguare feet
23.66
23.33
96.09
35-10
7.03
14-25
37.26
Weight of fuel burned on each square foot of grate,
3.46
4.00
10.75
20.34
79.33
46.82
13.31
per hour, in lbs
Cabic feet of water evaporated from initial tempera-
18.87
16.44
13.91
14.11
11.14
ture by 112 lbs. of fuel
Cubic feet of water evaporated per hour from initial
13.81
13.79
34.40
90.7
55-18
temperature
Square feet of heated surface for each cubic foot of
69.58
11.00
9.96
5.06
6.06
17.17
water evaporated per hour
Square feet of heated surface for each square foot of
40.65
6.51
13.13
13.08
47.59
56.0
15.78
grate.
Pressure of steam above the atmosphere in lbs
42-2
2.5
3.68
1.5
50
15-45
Kind of coal used*
W.
S.
L.&N.
N.
Coke.
N.
N.
W. Welsh.-S. Staffordshire.-L. Lancashire.-N. Newcastle.
The grand secret, however, of the economy of the Cornish engines lies in the large application of the
principle of expansion, and the results there obtained are very little aided by any peculiar excellence in
the boiler. Upon the merits of expansion, however, or the pitch to which it may be beneficially carried
in particular cases, this is not the place to enlarge, but we may here give a table which shows the
relative efficacy of different engines with different degrees of expansion.
Holmbush,
Cornish con-
densing En-
Smeaton's At-
Boulton and Watt's
gine, single
Noncondensing
mospheric
non-expansive ro-
acting, for
double-acting
Cornish En-
Boulton and
TABLE IL
Engine,Long
tative condensing
pumpingwa-
Engine, non-
gine,
East
Watt's Pump-
Benton,Nor-
Engine, Albion
ter. Steam
London Wa-
ing Engine at
expensive,
thumerland,
Mills,
acts expan-
Congleton,
ter Works.
East London
London,
Water Works.
date 1772.
date 1786.
sively after
Cheshire,1828.
the first sixth
of the stroke,
1836.
Diameter of cylinder in Inches.
52
34
50
13
794
594
Length of stroke in feet
7
8
9.1
4
10
7.91
Number of strokes per minute.
12
16
4.63
27.5
7
11.5
Pressure on the piston, above or
below the atmosphere, in lbs.
Estimated at
+30
+20
+5.17
+2.15
2.5
per square inch
Weight in lbs. raised one foot by
112 lbs. of coals
12,600,000
25,756,752
140,484,848
12,418,560
105,664,118
46,602,333
Weight in lbs. raised one foot by
one pound of water. as steam.
14,280
28,489
119,097
15,840
110,716
53,369
Effective power of the engine at
time of experiment in horse
40.5
50.0
26.48
12.0
power
Efficiency of the steam, its offi-
ciency in the Albion Mills
.501
1·000
4-180
.556
3.89
1.87
being unity
Efficiency of the fuel, its effi-
ciency in the Albion Mills
.480
1.000
5.454
-482
4.1
1.81
being unity
Distance of the piston from the
end of its stroke when the
0
0
833
0
687
-5
steam is cut off in parts of the
length of stroke
The first column on the left exhibits the performance of Smeaton's atmospheric engine at Long
Benton. In the second column will be found similar particulars of Boulton and Watt's condensing
rotative engine at the Albion Mills. In the third column we have put down the same data for the
Holmbush Cornish engine; and, in the fourth, for a high-pressure non-condensing engine, whose duty
was determined by Mr. Wicksteed. The last two columns supply the same data for a Cornish engine
and Boulton and Watt pumping-engine, at the East London Water Works. The economical effects of
expansion will be found to be very clearly exhibited in this table. The duties are recorded in the fifth
line from the top, and the degree of expansion in the bottom line. It will be observed, that the order
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BOILERS.
in which the different engines stand in respect of superiority of duty is the same as in respect of amount
of expansion. The Holmbush engine has a duty of 140,484,848 lbs. raised 1 foot by 1 cwt. of coals,
and the steam acts expansively over 830 of the whole stroke; while the water-works' Cornish engine
has only a duty of 105,664,118 lhs, and expands the steam over only 687 of the whole stroke. Again,
comparing the two Boulton and Watt engines together, the Albion Mills engine has a duty of 25,756,752
lbs., and no expansive action. The water-works' Boulton and Watt engine, again, acts expansively over
one-half of its stroke, and has an increased duty of 4,660,333 lbs. Other causes, of course, may influence
these comparisons, especially the last, where one engine is a double-acting rotative engine, and the
other a single-acting pumping one; but there can be no doubt that the expansive action in the latter is
the principal cause of its more economical performance.
The heating service per horse power allowed by Boulton and Watt is about 9 square feet in wagon
boilers, reckoning the total surface as effective surface, if the boilers be of a considerable size; but in
the case of small boilers, the proportion is larger. The total heating-surface of a two-horse power
wagon boiler is, according to Boulton and Watt's proportions, 30 square feet, or 15 ft. per horse
e
power; whereas, in the case of a 45-horse power boiler the total heating-surface is 438 square feet, or
96 ft. per horse power. The capacity of steam-room is 84 cubic feet per horse power, in the two-horse
power boiler, and 51 cubic feet in the 20-horse power boiler; and in the larger class of boilers, such as
those suitable for 30 and 45 horse power engines, the capacity of the steam-room does not fall below
this amount, and indeed is nearer 6 than 54 cubic feet per horse power. The content of water is 18,
cubic feet per horse power in the two-horse power boiler. and 15 cubic feet per horse power in the 20-
horse power boiler. In marine boilers about the same proportions obtain in most particulars. The
original boilers of the Great Western" steamer, by Messrs. Maudslay, were proportioned with about
half a square foot of fire-grate per horse power, and 10 square feet of flue and furnace surface,
reekoning the total amount as effective; but in the boilers of the "Retribution," by the same ma-
kers, a somewhat smaller proportion of heating-surface was adopted. Boulton and Watt have found
that in their marine flue-boilers 9 square feet of flue and furnace surface are requisite to boil off
a cubic foot of water per hour, which is the proportion that obtains in their land boilers; but in-
asmuch as in modern engines the nominal considerably exceeds the actual power, they allow 11
square feet of heating-surface per nominal horse power in their marine boilers, and they reckon as
effective heating-surface, the tops of the flues, and the whole of the sides of the flues, but not the
bottoms. They have been in the habit of allowing for the capacity of the steam space in marine boilers
16 times the content of the cylinder; but as there are two cylinders this is equivalent to 8 times the
content of both cylinders, which is the proportion commonly followed in land engines, and which agrees
very nearly with the proportion of between 5 and 6 cubic feet of steam-room per horse power. Taking,
for example, an engine with 23 inches diameter of cylinder and 4 feet stroke, which will be 184 horse
power-the area of the cylinder will be 415476 square inches, which multiplied by 48, the number of
inches in the stroke, will give 19942-848 for the capacity of the cylinder in cubic inches; 8 times this is
159542-784 cubic inches, or 923 cubic feet; 92.3 divided by 184 is rather more than 5 cubic feet per
horse power. There is less necessity, however, that the steam space should be large when the flow of
steam from the boiler is very uniform, as it will be where there are two engines attached to the boiler
at right angles with one another, or where the engines work at a great speed, as in the case of
locomotive engines. A high steam-chest too, by rendering boiling over into the steam-pipes, or priming,
as it is called, more difficult, obviates the necessity for so large a steam space; and the use of steam of
a high pressure, worked expansively, has the same operation; so that in modern marine boilers, of the
tubular construction, where the whole of these modifying circumstances exist, there is no necessity for
so large a proportion of steam-room as 5 or 6 cubic feet per horse power, and about half that amount
more nearly represents the general practice. Boulton and Watt allow 0.64 of a square foot per nominal
horse power of grate-bars in their marine boilers, and a good effect arises from this proportion; but
sometimes so large an area of fire-grate cannot be conveniently got, and the proportion of half a square
foot per horse power seems to answer very well in engines working with some expansion, and is now
very widely adopted. With this allowance, there will be about 22 square feet of heating-surface per
square foot of fire-grate, and if the consumption of fuel be taken at 6 lbs. per nominal horse power per
hour there will be 12 lbs. of coal consumed per hour on each square foot of grate. The flues of all flue
boilers diminish in their calorimeter as they approach the chimney some very satisfactory boilers have
been made by allowing a proportion of 06 of a square foot of fire-grate per nominal horse power, and
making the sectional area of the flue at the largest part one-seventh of the area of fire-grate, and the
smallest part where it enters the chimney one-eleventh of the area of the fire-grate; but in some of the
"boilers proportioned on this plan the maximum sectional area is only 7:3 or g'3, according to the
purposes of the boiler. These proportions are retained whether the boiler is flue or tubular, and from
14 to 16 square feet of tube surface is allowed per nominal horse power; but such boilers, although
they may give abundance of steam, are generally, perhaps needlessly, bulky.
We must now, however, dismiss these speculations, and with them the whole subject of the efficacy
of different kinds of boilers, upon which we have already expatiated sufficiently we shall therefore
conclude our remarks upon the subject by introducing a table of the comparative evaporative power of
different kinds of coal, which we have derived from Mr. Wicksteed's experiments, and which will prove
useful, by affording data for the comparison of experiments upon different boilers when different kinds
of coal are used. Without this means of reduction, experiments would be useless for comparison, unless
the fuel employed was in every case of equal evaporative power; but when the relation between the
evaporative power of different kinds of coals is ascertained, the results of experiments can be easily
reduced so as to render them comparable with one another.
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TABLE of the Comparative Evaporative Power of different kinds of Coal.
Water evapor-
No.
Description of Coals.
ated per lb.
Value per Ton
in the Pool.
of Coals.
Lbs.
8.
d.
1
The best Welsh
9.493
17 11
2
Anthracite
9.014
17 0
3
The best small Newcastle
8.524
16 1
4
Average small Newcastle
8.074
15
21
5
Average Welsh
8.045
15 21
6
Coke from Gas-works
7.908
14 11
7
Coke and Newcastle, small, half and half
7.897
14 101
8
Welsh and Newcastle, mixed half and half
7.865
14 10
9
Derbyshire and small Newcastle, half and half
7.710
14 61
10
Average large Newcastle
7.658
14 53
11
Derbyshire
6.772
12 94
12
Blythe Main, Northumberland
6.600
12
53
Strength of Boilers.-The extension of the expansive method of employing steam to boilers of every
denomination, and the gradual introduction in connection therewith of a higher pressure than formerly,
makes the question of the strength of boilers one of great and increasing importance. This topic was
very successfully elucidated a few years ago by a committee of the Franklin Institute, and we shall
here recapitulate a few of the more important of the conclusions at which they arrived. Iron boiler-
plate was found to increase in tenacity as its temperature was raised until it reached a temperature of
550° above the freezing point, at which point its tenacity began to diminish. The following table
exhibits the cohesive strength at different temperatures:-
At 32° to 80° the tenacity was = 56,000 lbs., or 1-7th below its maximum.
At 570°
"
"
" = 66,500 lbs., the maximum.
At 720°
"
"
"
= 55,000 lbs., the same nearly as at 32°.
At 1050°
"
«
"
= 32,000 lbs, nearly 1 of the maximum.
At 1240°
a
"
" = 22,000 lbs, nearly 1 of the maximum.
At 1317°
"
"
"
= 9,000 lbs., nearly 1-7th of the maximum,
At 3000° iron becomes fluid.
The difference in strength between strips of iron cut in the direction of the fibre, and strips cut across
the grain was found to be about 6 per cent. in favor of the former. Repeated piling and welding was
found to increase the tenacity and closeness of the iron, but welding together different kinds of iron was
found to give an unfavorable result riveting plates was found to occasion a diminution in their
strength, to the extent of about one-third. The accidental overheating of a boiler was found to reduce
its strength from 65,000 lbs. to 45,000 lbs. per square inch. Taking into account all these contingencies,
it appears expedient to limit the tensile force upon boilers in actual use to about 3000 lbs. per square
inch of iron.
Copper follows a different law, and appears to diminish in strength by every addition of heat,
reckoning from the freezing point. The square of the diminution of strength seems to keep pace with
the cube of the temperature, as appears by the following table :-
TABLE showing the Diminution of Strength of COPPER Boiler-Plates by additions to the
Temperature, the Cohesion at 32° being 32,800 lbs. per Square Inch.
Temperature
Diminution of
Temperature
Diminution of
No.
No.
above 32°.
Strength.
above 32°.
Strength.
1
90°
0.0175
9
660°
0.3425
2
180
-0.0540
10
769
0.4398
8
270
0.0926
11
812
0.4944
4
360
0.1518
12
880
0.5581
5
450
0.2046
13
984
0.6691
6
460
0.2133
14
1000
0.6741
7
513
0.2446
15
1200
0.8861
8
529
0.2558
16
1300
1·0000
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BOILERS.
In the case of iron, the following are the results when tabulated after a similar fashion.
TABLE of Experiments on IRON Boiler-Plate at High Temperatures; the Mean Maximum Tenacity
being at 550°65,000 lbs. per Square Inch.
Temperature
Diminution of Tena-
Temperature
Diminution of Tena-
observed.
city observed.
observed.
city observed.
550°
0.0000
824°
0-2010
570
0-0869
932
03324
596
0-0899
947
0-3593
600
0-0964
1030
0.4478
630
0.1047
1111
0.5514
662
0-1155
1155
0-6000
722
0-1436
1159
06011
732
0-1491
1187
0.6352
734
0-1535
1237
06622
766
0.1589
1245
0.6715
770
0.1627
1317
0-7001
The application of stays to marine boilers, especially in those parts of the water spaces which lie in
the wake of the furnace bars, has given engineers much trouble; the f-plate, of which ordinary boilers
are composed, is hardly thick enough to retain a stay with security by merely tapping the plate,
whereas, if the stay be riveted, the head of the rivet will in all probability be soon burnt away. The
best practice appears to be to run the stays used for the water spaces in this situation, in a line some-
what beneath the level of the bars, so that they may be shielded as much as possible from the fire,
while those which are required above the level of the bars should be kept as nearly as possible towards
the crown of the furnace, 80 as to be removed from the immediate contact of the fire. Screw-bolts
with a fine thread tapped into the plate, and with a thin head upon the one side, and a thin nut made of
a piece of boiler-plate on the other, appear to be the best description of stay that has yet been contrived.
The stays between the sides of the boiler-shell, or the bottom of the boiler and the top, present little
difficulty in their application, and the chief thing that is to be attended to is to take care that there be
plenty of them; but we may here remark that we think it an indispensable thing, when there is any high
pressure of steam to be employed, that the furnace-crown be stayed to the top of the boiler. This, it
will be observed, is done in the boilers of the Tagus and Infernal, constructed by Messrs. Miller, Raven-
hill and Co.; and we know of no better specimen of staying than is afforded by those boilers.
Explosion.-This subject has been investigated with much care by the committee of the Franklin
Institute, whose experiments on the strength of boilers we have already mentioned with commendation.
We are unable, however, to follow these experimentalists in their researches, and have only room to
remark that we believe most explosions will be found to have arisen either from an undue pressure of
the steam, or from the overheating of the plates composing the boiler. The plates of the boiler may
become overheated either in consequence of a want of water in the boiler. or from such a configuration
of the internal parts of the boiler that the steam when formed cannot escape freely to the surface.
The bottoms of large flues upon which the flame beats down are very liable to injury from this cause
and the iron in such a case will probably be softened by the heat, and in all probability will collapse
upwards. Lightning, the sudden disengagement of large portions of scale, and other similar accidents
have, we believe, caused explosions sometimes. But these causes are of very unfrequent occurrence in
comparison with those that we have indicated, and which would be oftener recognised as the real causes
of explosions, were it not that people think they show their cleverness best by clearing up a difficulty
with a new hypothesis that has been coined for the purpose in fancy's mint.
The plugs of fusible metal sometimes introduced into boilers to obviate explosions by melting out
before the steam can reach any high temperature, are found in practice to be of but little avail. The
compound metal is not homogeneous, and the more fusible of the metals is melted first, and is forced by
the pressure of the steam out of the interstices of the less fusible metal, leaving its place to be supplied
by the debris which all water supplies. The consequence is that the plug ceases to be fusible metal of
the kind originally introduced, and cannot be melted by the steam even at a pressure and temperature
much above that fixed as the requisite fusing point. Plugs of fusible metal should, therefore, we think,
be discarded, as they are only calculated to mislead by pretending to do what they cannot accomplish.
In tubular boilers, however, it is, we think, a good plan to introduce lead plugs in the tops of the fire-
boxes-not with the idea that they will be melted by the steam where its pressure gets high, but to be
melted out, and give notice of danger should the water fall too low.
Every boiler should be furnished with a steam-gage, which may give indication of danger should
the pressure become too great, and the passages leading to the safety-valves should have no connection
with the pipes leading to the stop-valves. In some cases stop-valves have been lifted from their seats,
and forced into the mouth of the pipe, 80 that no steam could escape thereby; and in consequence of
the safety-valve pipe springing from the pipe connecting the boilers, the boiler thus blocked up was in
great danger of bursting, and would have burst if the fires had not been immediately drawn. "In the
case of any derangement of the safety-valve, or of the cone in the waste steam-pipe of a steam-vessel
getting loose, and blocking up the mouth of the pipe, the pressure in the boiler may be eased by open-
ing the blow-through valves of the engines, and the steam-gage will in all cases tell whether any
undue pressure exists.
Incrustation.-The incrustation of boilers by saline deposites was a much more important subject at
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BOILERS.
153
one time than it is now, as nothing has been more clearly established, of late years, than that boilers
may be preserved effectually from any injurious incrustation by abundant blowing off. Brine-pumps
are now in extensive use for withdrawing a certain quantity of water at every stroke of the engine;
and the water so withdrawn has to pass through or among pipes carrying the feed-water to the boiler,
80 that some interchange of heat is there effected. These refrigerators, however, as they are grotesquely
called, are in some respects bad things: the quantity of heat they save is, we believe, inappreciable;
and the small pipes of which they are built up are liable to get choked, thereby endangering the boiler
by the unconscious concentration of its contents. To guard against this danger, every engine fitted with
brine-pumps should be provided with an hydrometer for telling the specific gravity of the water in the
boiler, 80 that the engineer may not be cheated by the defective action of the pumps, or suppose that
they are operating when they are really inert. In the case of blowing out a boiler in the usual way,
the engineer looks at his glass gage-tube, and keeps the blow-off cock open until the water-level has
descended through the required distance, 80 that, under these circumstances, no doubt can arise that the
boiler has been emptied of a certain quantity of water; but there is no such assurance in the case of
the continuous extraction of the water, either by brine-pumps or by a continuous blow-off; and all
boilers using either of these expedients should be fitted with hydrometer gages as a precaution against
the contents of the boiler being suffered to reach an injurious concentration. Numerous prescriptions
have at various times been given as antidotes to incrustation; such as putting potatoes and other vege-
table matters in the boiler, or, in the case of a steam-vessel, taking the feed-water from the bilge. The
application of oil to the flues has also been recommended; and some boilers are fitted with a contri-
vance to inject oil into them just before the steam is let down. We look upon all such expedients, how-
ever. as needless, and are confident that boilers require no other preservation from incrustation than
effectual blowing off. Collecting vessels, however, are advantageous, as they enable a less amount of
blowing off to suffice; and, in the case of the feed supplied to the boiler being muddy water, they con-
duce to convenience and save fuel by obviating priming. The prevailing fault among engineers, how-
ever, is that they do not blow off enough, the idea probably being that a considerable check is given to
the generation of the steam by the introduction of colder water in lieu of the water abstracted; but the
waste of heat by effectual blowing off is very inconsiderable-much less, indeed, than is occasioned by
the difficulty of getting steam from brine, or of transmitting heat to the water through flues covered
with incrustation, much of which heat, in consequence, ascends the chimney. There is no gain, there-
fore, in any respect, by penuriousness in blowing off; and there is much injury to the boiler, for incrusted
plates become overheated; they blister, crack, and get burned out, and make expensive repairs indis.
pensable. Proprietors of engines should accept of no excuse for the accumulation of salt or incrustation
within their boilers; for such deposites arise altogether from insufficient blowing off.
The best method of scaling boilers appears to be by lighting a train of shavings in the furnaces and
flues after the boilers have been emptied of water. The rapid expansion of the metal, thus occasioned,
causes the scale to crack off; and, if the flues be then washed down with a hose, the scale will fall to the
bottom of the boiler, and will issue out with the water on taking off the mud-hole doors. This plan of
scaling, however, is one that the engineer must execute himself, and must not intrust to firemen or other
subordinates, as the metal of the boiler might be damaged if the heat were made too great. The safety-
valve should, obviously, be kept open while the boiler is being heated and cooled, to obviate any pres-
sure or exhaustion within it. This plan of scaling, however, will seldom be necessary if due attention
be paid to blowing off by the engineer; and if the quantity of scale be inconsiderable, or partial in its
attachment, the best plan will be to chip it off with a hatchet-faced hammer, and then wash down the
flues with the hose, as before described.
Corrosion.-The corrosion of boilers is one of the most obscure subjects in the whole range of engi-
neering. Marine boilers seldom last more than four or five years, whereas land boilers, made of the
same quality of iron, often last eighteen or twenty years; yet the difference in durability is not the
effect of any chemical action upon the iron by the contact of sea-water, for the flues of marine boilers
rarely show any deterioration from this cause, and, even in worn-out marine boilers, the hammer-marks
on the flues are as conspicuous as at the time of their formation. The thin film of scale spread over
the internal parts of the boiler would, of itself, preserve that part of the iron from corrosion which is
situated below the water-level; but, whatever be the cause, it is a rare thing to find any internal cor-
rosion of a boiler using salt water in those parts of the boiler with which the water comes in contact.
The cause, therefore, of the rapid wearing out of marine boilers is not traceable to the chemical action
of salt water, and steamers provided with Hall's condensers, which supply the boilers with fresh wa-
ter, have not reaped much benefit in the durability of their boilers. The operations of the steam in
corroding the interior of the boiler is most capricious-the parts which are most rapidly worn away
in one boiler being untouched in another, and in some cases one side of a steam-chest will be very
much wasted away while the opposite side remains uninjured. Sometimes the iron exfoliates in the
shape of a black oxide which comes away in flakes like the leaves of a book, while in other cases the
iron appears as if eaten away by a strong acid which had a solvent action upon it. The application of
felt to the outside of a boiler, has in several cases been found to accelerate sensibly its internal corro-
sion. Boilers in which there is a large accumulation of scale appear to be more corroded than where
there is no such deposite, and where the funnel passes through the steam-chest the iron of the steam-
chest is invariably much more corroded than where the funnel does not pass through it. These facts
appear to indicate that the internal corrosion of marine boilers is attributable chiefly to the existence of
surcharged steam within them, which is steam to which an additional quantity of heat has been com-
municated subsequently to its generation, so that its temperature is greater than is due to its elastic
force; and on this hypothesis the observed facts relative to corrosion become easily explicable. Felt
applied to the outside of a boiler may accelerate its internal corrosion by keeping the steam in a sur-
charged state, when by the dispersion of a part of the heat it would cease to be in that state. Boilers
in which there is a large accumulation of scale must have worked with the water very salt, which
20
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BOLTING-MILL.
necessarily produces surcharged steam; for the temperature of steam cannot be less than that of the
water from which it is generated, and inasmuch as the boiling point of water, under any given pressure,
rises with the saltness of the water, the temperature of the steam must rise with the saltness of the
water, the pressure remaining the same; or in other words the steam must have a higher temperature
than is due to its elastic force, or be in the state of surcharged steam. The circumstance of the chim-
ney-flue passing through the steam will manifestly surcharge the steam with heat, so that all the cir-
cumstances which are found to accelerate corrosion are, it appears, such as would also induce the
formation of surcharged steam. Besides, the natural effect of surcharged steam is to oxidate the iron
with which it is in contact, as is illustrated by the familiar process for making hydrogen gas by sending
steam through a red-hot tube filled with pieces of iron; and although the action of the surcharged
steam in a boiler is necessarily very much weaker than where the iron is red-hot, it manifestly must
have some oxidizing effect, and the amount of corrosion produced may be very material where the
action is perpetual. Boilers with a large extent of heating-surface, or with descending flues circulating
through the cooler water in the bottom of the boiler before ascending the chimney, will be less corroded
internally than boilers in which a large quantity of the heat passes away in the smoke. If these
views be correct, then to prevent the internal corrosion of marine boilers it is only necessary to take
care that the water in the boiler shall be as fresh as possible, and that the root of the chimney shall
either be lined with fire-brick, or not go through the steam at all.
463.
steam Pips
462.
D
S
P
These boilers, which have now been in use by the Lowell Manufacturing Company at Lowell for two
years, were constructed, from directions by Dr. A. A. Hayes, of Boston, by Messrs. Bancroft, Nightin-
gale & Co., of Providence. One row of four boilers are set perpendicularly above another row of the
same number, the fires being under the lower tier. The boilers are plain cylinders, 40 feet long and 33
inches diameter, having a surface exposed to the fires of 2,000 square feet, and containing about 1,200
cubic feet of water. The grates are in two heights of 3 feet 2 inches each, with a width of 12, feet,
giving a fire surface of about 80 square feet. Each grate is 11 inch thick, having between it and the
next one a space of a quarter of an inch wide, giving the whole of the space for the passage of the air
to the fires equal to about 101 square feet. The dampers at the back end of the boilers are usually
kept open about four inches, giving an area of four and one-sixth square feet for the exit of the smoke.
The upper and lower tiers are connected by thimbles in four places in each boiler between their ends,
while at the ends are a number of connections, as shown. The thimbles are of cast-iron, having a socket
turned in its upper part, into which a tube is set, reaching to within eight inches of the top of the upper
boiler. The connections at the ends are of cast composition metal, and notwithstanding their number no
leakages have occurred. A steam drum, 11 feet long and 33 inches diameter, is connected with each of
the upper boilers, and is placed above them; from this drum steam is taken to the engines. Accurate
measurements and accounts have been kept of the amount of coal used, and of the water evaporated
by it, which show that for the last year together, the average amount of water evaporated to one pound
of coal consumed was 9.66 lbs.
The amount of coal consumed under each nest of eight boilers per day is about 21 tons. and by com-
paring the weekly averages of effect, it appears that, even with this large amount of boiler compared
to the fire surface, that the less the amount of coal consumed per day the better the effect.
For example: the amount of coal consumed under two nests of these boilers during the week ending
Feb. 18th, 1848, was 65 tons, which evaporated 8.72 lbs. of water for each pound of coal consumed, and
during the week ending July 14th, 1849, 21 tons of coal only were burned, and 10.44 lbs. of water were
evaporated for each pound of coal consumed. The best result from a week's working was obtained du-
ring the week ending May 7th, 1849, when 11.62 lbs. of water were evaporated by each pound of coal
consumed.
The steam from two nests of these boilers is used at a pressure of 65 lbs. per square inch, by a
double high-pressure engine of 200-horse power, and a single engine of 40-horse power, both of which
exhaust into pipes under a pressure of five pounds per square inch, from which it is used for dying, dry-
ing, and heating.
BOLTING-MILL for flour. A bolting-mill is the general name of a place where meal is sifted.
But here the subject in question is particularly a dressing or bolting machine in common mills, by which
either the bran is separated from the flour or meal, or the ground grain, ore, &c., is refined. The bolting-
machines most in use are-1st. The common bolter; 2d. The rotative cylindric or prismatic bolter; and
3d. The brush-bolter. Though they differ from each other in structure, the substantial arrangement
consists in a kind of sieve of wire or horsehair, or of cotton or silk texture, of bolting-cloth or of silk-
gauze, either of which stuff is used according to the fineness of the meal required; the meshes or per-
forations of the one being smaller than those of another.
The peculiarity of the common bolter is, that the sifting is effected by its shaking motion that of the
cylindrical or prismatic bolter is, that the sifting is produced by its rotative motion, either alone, or by
co-operation of the centrifugal power, or of beaters or similar apparatus.
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The peculiarity of the brush-bolter is, that the sifting is effected by brushes placed in the interior of
the bolter itself, which latter discharges its coarser contents into the bran-chest; while the meal or flour
is taken up in the bolting-hutch.
The common bolter is still most in use, at least in Germany, and other countries of the European
continent, because it is the most simple; although in recent times the cylindric and prismatic bolter
have here and there been introduced and applied successfully.
The arrangement of the improved bolter in general use, will be perceived by Figs. 463, 464, 465, and
466, where Fig. 463 represents the bolting-machine in longitudinal section; Fig. 464 ground-plan, (but
without the lid of the bolting-hutch;) Fig. 465 front, and Fig. 466 side-view of the hind part, together
with the mechanism for effecting the shaking motion.
The oblong and closed bolting-hutch, marked by a a, is fastened to the meal-bench b; and in its in-
terior, at an angle of 15, or, at the most, 30 degrees, is placed the bolter or sifter c c, whose upper end
is fastened to the scuttle d, Figs. 463 and 464, and whose lower end discharges its contents at the
fore side of the hutch a a.
The bolter consists commonly of bolting-cloth or silk-gauze, of which two strips from 6 to 7 feet in
length, and from 14 to 16 inches in breadth each, are sewed together lengthwise. The seams are
edged, two inches broad; and the two ends of the bolter are likewise bordered with leather, for the
purpose of fixing iron rings. The ring at the upper end is quadrangular, yet with rounded corners it
is 8 inches broad, and from 5 to 6 inches diameter. At about 2 feet down from the upper end of
the bolter, two handles, (called bolter-ears, and marked by the letter e,) of strong sole-leather, are sewed
to the sides, to serve for the reception of two arms ff, of the apparatus for effecting the shaking mo-
tion. The lower end of the tight-stretched bolter is placed in the aperture cut out in the slide g on the
outside of the bolting-hutch; the shaking-arms ff, which are either covered with tin-plate, or with ends
of cast-iron, are to be put through the two bolter-ears e; and the upper end of the sifter is to be placed
on the outside of the scuttle d, in the notch of the wooden ledge h, Fig. 463, and fixed by the iron cramp i.
At the lower end the screws k k of the slide g are designed to stretch the bolter as required.
The motion of the bolter may either be horizontal or perpendicular. The former is most general,
as the bolter is more worn by the perpendicular motion. But it may be asserted that the case is
almost entirely the reverse. For by the lateral motion the sides of the bolter are very much tossed,
and 80 their threads too much stretched, especially when the shaking-arms ff stand out straight from the
shaking-axis, forming thus an acute angle with the bolter. By the perpendicular motion the bolter is
also violently tossed; however, this inconvenience may be removed by using curved arms, (like that
marked by f in Fig. 463,) instead of rectilinear ones, and made either of timber or iron.
The vertical shaking motion of the bolter is produced in the following simple way: At the axis l,
placed horizontally beneath the sifter, are fixed the two shaking-arms ff; also at its projection the bent
arm m, called the bolter, in which the bolter-tongue is, by means of a peg, fastened in a manner which
allows of its turning. The bolter-tongue is pressed against the horizontal arm o of a vertical axis p, by
the wooden or steel spring q, 80 firmly and continually that a retrograde motion results from the re-
bounding of this spring, while the advancing motion is effected by a second arm r of the axis p, which
beats against three tenons t, and is pushed off again by them.
The power of this shaking motion can be modified according to the required fineness of the flour, or
to the more or less fine bolting-cloth; and this is effected by displacing the bolter-tongue n in the
wheel-scissors m, for which purpose both are perforated. However, the bolter is not suffered to move
more than 3 inches up and down, as this is sufficient even for the coarsest grit, while a more vigorous
movement would wear the bolter too much.
The upper millstone in a common mill, of 3 feet in diameter, making from 140 to 180 rotations a
minute, each bolter, brought in connection with a set of such stones, will be moved up and down thrice
80 often, or 420 to 540 times in a minute. In order to be enabled to look frequently at the bolter, there
is made in one of the side partitions of the bolting-hutch a large square aperture и 26, commonly covered
with a linen cloth v, Fig. 464. Another aperture w, about 6 inches high and wide, at the bottom of the
hutch, is provided with a slide of wood or tin-plate, and serves as an outlet for the flour.
Beneath the lower end, or mouth of the bolter, is a small gutter x, made of wood or tin-plate, in order
to facilitate the emptying of the grit or bran into the bran-chest below. The mouth of the bolter is
covered with a cloth y, Fig. 465, pressed towards the mouth of the bow x, to prevent the flour-dust,
joined to the grit and bran, from dusting away.
Should the under side of the bolter become defective, it is commonly mended by putting in a new
piece of cloth; or, should this be of no avail, the upper side of the bolter may be turned down.
The apparatus used for bolting ores containing silver or gold, after they have been ronsted with salt
and ground, is somewhat different from the bolting-machinery in corn-mills. At Freiberg (a celebrated
mining town in Saxony) a similar bolter as the above-described is used, with the only difference that it
is made of double bolting-cloth, whose threads are twined, to make it stronger. The ore-dust being
very warm, and for this reason easily brought to rise, the bolting-hutch is made of very dry timber, and
its boards are not only joined together carefully, but also grooved and glued. The aperture in the side-
partition, Fig. 463, uu, is beside the curtain, Fig. 464, v, closed with a door or slide, while on the other
hand, the bran-chest is 11 feet in length, and closed tightly.
The bolting-cloth used in bolting-mills consists generally of woollen, more seldom of silk texture, and
is glued or gummed in a particular manner. According to the species of corn to be bolted, and to the
fineness of the flour, the cloth is coarse or fine, both in the threads and the size of its perforations or
meshes. There are more than a dozen sorts of cloth, which are selected according to the quantity of
meshes in an inch square. The cloth is commonly from 14 to 16 inches broad, thus being adapted for
the use of bolters from 10 to 12 inches in diameter. The English manufacture bolting-cloth noted for
its good quality and durability; there are also in Germany superior manufacturers of this article,
especially at Lins, Berlin, and Breslau. The best quality bolting-cloth and silk-gauze is fabricated by
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BOLTING-MILL.
Dufour & Co., at Thal, in the Swiss canton of St. Gall, by Hennecart, at St. Quentin, in France, and by
Harlem Star, in Holland.
We shall now describe those bolting-mills where the cylindrical bolter is used.
Formerly, in England and the United States, a bolting-mill of this description was used, in which the
cylindrical bolter, put in circular motion with great celerity, consists of a kind of reel, framed in the
following manner :-From a somewhat inclined axis, like radii, six arms or spokes project, which are con-
nected with each other by six laths running parallel with the axis. This cylindrical frame is commonly,
at the upper end, 221 inches diameter, but at the lower end only 201 inches, (in this case it is called
taper-reel;) sometimes it is at both ends 221 inches diameter, in which case it is called an equal-reel.
The wider cylindrical bolter encloses the frame, and is at both ends (which are lined with leather)
fastened to it. In the bolting-hutch are placed six wooden beaters, whose points stand off half an inch
from those of the spokes. Now, as soon as the bolting-cloth is swelled by the rotation and centrifugal
power, it strikes violently upon these beaters, and thus the finer elements of the flour are forced
through the sides of the bolter, while the grit and bran proceed along the whole bolter into the bran-
chest at the outside of the bolting-hutch.
Yet this bolting apparatus was not much adapted to the purpose, because the ends of the bolter
could not be fixed firmly enough to prevent its unsteady, swinging motion, and its too violent striking
upon the beaters, by which the bolting cloth soon became defective. However, at present this bolting-
mill is substantially improved by James Ayton.
Fig. 467 gives a side view of this improved machine, without the bolter, and without the front of
the hutch. In the frame of the bolting-hutch a a, the apparatus is placed obliquely. By the axis bb,
(made of forged iron,) and the disk c, the bolting-machine is brought in rotation. At the axis b b are
fixed the two naves d and e, in a proper manner, and into both are placed four spokes ff, at right angles
with each other. From each spoke to the corresponding opposite one, or from f to is distended a
strip of bolting-cloth or duck g, 5 to 6 inches broad, fixed at the extremities of the spokes. The strips
in the interior of the bolter form a kind of fanning-machine of about 20 inches diameter. Above
the nave d is another one h, from which project six iron spokes, bent upwards, and connected with each
other at their points by the wooden ring k, whose diameter is equal to that of the fanning-machine.
Below the board partition 11, that separates the flour-hutch m from the bran-chest n, is a third nave o,
from which project six steel springs p, whose points are bent into hooks, carefully rounded off and pol-
ished, that the handles of the bolter (which are fixed to them) may be spared as much as possible.
This nave, which by Fig. 468 is twice represented on a larger scale, consists of three hoops o qr, of
which the inner q is fastened to the square axis bb; the middle o revolves round the hoop q, and the
outer r is fastened to the hoop q by four screws.
The bolter surrounding the fan-shaped reel is, by means of its handles at the lower end, fixed at the
hooks of the six steel springs p; while its upper end, above the wooden ring k, is simply drawn to-
gether by a cord or string. As soon as the reel is in rapid rotation, the pressure of the air, produced
by the fans and the centrifugal power, will swell the bolter, which at the same time is kept at a uni-
form concentric tension by the elasticity of the steel springs p.
Another substantial improvement of Ayton's bolting-mill is, that the six beaters 8, lying round the
bolter may, according to circumstances, be placed more or less near to it, even during the rotation.
The manner of this arrangement may be perceived by Fig. 469, where the machinery, Fig. 467, is repre-
sented in a view from behind or before. On the outside of each of the partitions 11 and tt, Fig. 467, is
a broad iron ring 16, Fig. 469, revolving round the axis b, in the small furrows of the six cramps marked
with v. In both of these rings (on the front and back) are cut six eccentric slits w w, behind which, in
the board partitions, there are cut out as many other slits, like radii of the axis bb, so that both kinds
of slits are crossing each other. The beaters 88, Fig. 467, are (by means of screws x) brought into con-
nection with the slits in such a manner, that they are moved to and fro in the slits of the partitions 11
and tt, and thus approach and turn off from the bolter, as soon as the outside rings и (which are not
connected with the axis bb itself) are turned round by the dented wheels y, Fig. 469. The whole
perimeter of the rings is dented; only a part of it is shown in Fig. 469. The dented wheels are con-
nected with another axis different from that marked with bb.
Through the hopper 2, Fig. 467, is constantly running the ground grain as required for bolting; 80
that from the other end of the bolting-hutch only grit or bran, without mixture of flour, runs out.
This improved bolting-mill has this substantial advantage over the older one-that the movement of
the air within the bolter is produced by the fans instead of the reel, and drives the flour towards the
periphery in a more complete manner. Thus the flour gets easily through the perforations of the
bolting-cloth, whose obstruction is almost entirely prevented by the trembling motion of the steel
springs p. The beaters are also arranged 80 that they cannot much wear out the bolter.
While by the older machinery (with 170 to 200 rotations a minute) only two and a half to three sacks
(measuring three bushels each) of grit are said to have been bolted in an hour, Ayton's improved mill
bolts four sacks in the same time.
Notwithstanding this favorable result, the improved bolting-mill is not much used, for the reason that
the bolter (as the weakest and most expensive part) is yet damaged by the beaters. The cylindrical
bolter has recently been supplanted by a hexagonal or octagonal one, with great success.
Figs. 470 and 471 show the frame of this bolting-machine (which is in very general use in this coun-
try) in longitudinal section and front view. The front partition is omitted, to get a better view of the
interior.
These bolters are made exclusively of silk bolting-cloth, manufactured by Harlem Star, in Holland.
For two sets of five-feet millstones there are generally made bolters of 28 inches in diameter and of 90
feet in length, and of three different sorts of cloth that is, 60 feet of the finest sort, No. 10 or 11 24
feet of the middling sort, No. 5 or 9; and the remaining 6 feet (60+24+6=90) of the third or coarsest
sort, No. 2, which latter is intended for separating the finer bran from the coarser.
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The cloth is tentered round wooden frames similar to the above-described reels, of hexagonal or oc-
tagonal form, 20 inches in diameter, and from 18 to 20 feet in length. The cloth is fastened with pins
to the wooden rings at both ends of the frame, and to six or eight laths running parallel with the axis,
and resting on spokes.
Such bolters, as a a, Figs. 470 and 471, are commonly placed four in one hutch bb, that is, two above
and two below, as in Figs. 470 and 471. They are placed somewhat obliquely, and, by means of the mo-
tive power cc, revolved all together by the wheel d of the axis, which also turns the wheel c. Each
bolter makes generally 25 rotations in a minute. The flour-conveyers, f and g, are commonly put in
motion by straps, (like the strap h, in Fig. 470,) they being highly adapted to the purpose, and more-
over simple and cheap. The conveyers are intended to remove immediately the bolted flour from the
butch of each pair of bolters without opening the hutch.
The ground grain passes through the common plate-iron gutters ii into the two superior bolters,
(where the cloth is of finer quality,) in such quantity as may be easily bolted by them. The mechan-
ism applied for this purpose will be described below. The flour bolted in the upper half of these two
bolters is somewhat finer than that bolted in their lower half, the former therefore being called extra-
superfine, and the latter superfine. All this flour falls through the oblique partitions kk, Fig. 471, into
the trough l of the upper conveyer. The wheels m n, Fig. 470, moving this conveyer, are covered by
the roof o. The coarser parts, or the grit and bran, issuing from the mouth of the bolter, fall into the
partition p of the bolting-hutch, and then, by means of the oblique board partition q, into the two lower
bolters of coarser cloth a₁. Thence the bolted flour goes into the trough of the lower conveyers g, and
the bran goes from the bolter's mouth through the gutter 8, Fig. 470,
The above-mentioned extra-superfine flour is, by means of the conveyer f, pushed to the wooden chan-
nel t, through which it then goes off into the flour-box, while the superfine flour is, by the channel и,
conveyed into the upper partition of the hutch, enclosing the two lower bolters a₁ a₁. Hence, mixed
with the flour of these bolters, it is by the lower conveyer g pushed to the channel v, through which it
goes off into the meal-elevator, that brings it back to the hopper-boy. Thence, having been mingled with
grit, it is conveyed once more into the bolter. In the case when the middling flour (or seconds) is ground
for the second time, the flour bolted by the upper and lower bolters is intermixed and not reconveyed
into the hopper-boy; but the gutter or channel v is shut, and the strap h (moving the conveyer crossed,
which has the effect of conveying the flour to the gutter or channel w, (which then is to be shut up,)
from whence it goes, together with the flour coming from the upper bolters down the gutter x, into the
flour-box.
The mechanism by which the ground grain or meal is conveyed into each of the two superior bolt-
ers, is to be seen in Fig. 472, longitudinal section, and Fig. 473, front view, on a larger scale. The letter
y marks a funnel, into which the ground mass falls down from a hopper-boy in a higher story, and thence
upon the moveable spout a, resting on the axis 2. The channel i, Fig. 471, is connected with this spout.
At the fore part of the spout's side-boards are the cross-rails ßB, by which, and by wedges, the sha-
king-bolt r is fastened. At the upper mouth of the bolters is a cast-iron cross δ, Figs. 470 and 471,
fastened to the axis, whose points are provided with heads, the forms of which may be seen by Figs.
471 and 472. During the rotation of the bolters, these heads touch upon the end point of the shaking-
bolt γ, Fig. 472, which lifts the spout a up and down. Thus the spout is constantly in a shaking mo-
tion, and the mass heaped in the funnel y is conveyed by the gutter i into the bolter a. By means of
the shutter & the aperture at the bottom of the front partition of the funnel y can be widened or nar-
rowed, according to circumstances.
The conveyers f and g consist of a screw, as may be perceived by Fig. 474, where they are repre-
sented on a larger scale. The chief part is commonly an octagonal strong wooden axis 1, round which,
in a helix, are put small wooden square tables 2, 2, at right angles to the axis.
These tables are generally 21 inches high and broad, and at the foot end half an inch thick, while
the back lessens to a sharp edge. The front sides (which retain their right angle with the axis) take
hold of the flour contained in the trough 3, and push it gradually on to the respective gutters. Beside
the slides, shutting the gutters u, x, t, v, w, there are in the bottom of the conveyer-trough as many
alides as possible, in order to prevent its obstruction during the movement of the conveyer.
In the above-described bolters the pushing of the flour through the perforations of the bolting-cloth
is produced in such a manner that the contents of the bolter are during its rotation cast up, and then by
their own weight fall upon the under side of the bolter; whereas, in the following rotative bolters (which
in all other respects are arranged like the other just mentioned) the bolting is effected by beaters or
other similar instruments. By this arrangement, the obstruction of the perforations is prevented with
more success.
Figa 482 and 483 represent a bolter of this kind and its hutch in longitudinal and transverse sec-
tions: and Figs. 484 and 485 represent the bolter in transverse section, and in a side view. The hex-
agonal wooden axis is marked by a a. From each of its six flat sides project six cylindrical staves b,
of hard timber, and one inch in diameter, and placed at the distance of two or three feet from each
other. The staves of every row are at their points connected with each other by a lath c, over which
the bolting-cloth is tentered, and to which it is fastened with pins. Upon each staff is put a little tube
of east-iron, 11 to 2 pounds weight, 3 to 4 inches long, 2 inches in the outer diameter, and called beaters.
During the rotation of the bolter, produced by the wheels e and f, Fig. 482, these beaters run up and
down the staves, Fig. 484, and by their beating against the hard-wood supports g, Fig. 484, underneath
the laths c, they prevent the obstruction of the perforations of the bolter. That the laths may not be
knocked of by this beating, there are commonly laid round bands either of leather or thin hoop-iron,
see hh, Fig. 485.
While the lower end of the bolter is left open to let out the grit or bran, the upper end is provided
with a wooden crown i, Figa. 482 and 483, whose interior diameter leaves only as much room as is re-
quired for the plate-iron gutter k, Fig. 482, by which the ground mass goes into the bolter. The crown
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i is provided with a funnel l of tin-plate, for the purpose of retaining the grit or flour within the
bolter.
A bolter of this kind is commonly from 16 to 26 feet long, and 24 to 30 inches diameter, and inclines
in the ratio of one-fifteenth to one-eighth of its length. Its silk bolting-oloth is selected out of two to five,
and even still more numbers. The first sort covers the greatest pat of the bolter from above, and then
follow in succession the coarser qualities. According to the variety of the flour to be obtained, there
are brought into connection with a set of 4 or 5 feet millstones, either one, or two, or more bolters,
which are placed in the above manner, (see Figs. 470 and 471.) The most proper arrangement is, that
the upper parts of the bolter (covered with the finer sorts of bolting-cloth) furnish the flour at once
completely bolted, while the less fine grit of the other parts is to be ground and again bolted.
The different qualities of flour or grit are taken up in separate partitions of the bolting-hutch, of which
a simple arrangement is represented by Figs. 482 and 483. The partitions n separate the lower part
of the bolting-hutch m m into the partitions 1, 2, 3, and 4, of which the first three take up three differ-
ent sorts of flour, while the partition 4 takes up the grit or bran issuing from the mouth of the bolter,
and has on its outside a hole (with the slide 0) through which the grit or bran comes out. The oblique
tables pp. Fig. 483, leave below an opening from 6 to 12 inches wide, through which the bolted flour
falls into the partitions. Each of the latter, 1, 2, and 3, is provided with a valve, consisting of a frame
covered with cloth, (see q, Fig. 482,) and whose hinges are marked by rr. The valve may be kept open
by fastening it to the buttons 8 8, Fig. 483.
Another proper arrangement for taking up the flour or grit, is shown by Figs. 486 and 487. Here the
bottom b of thesbolting-hutch a a, (which contains the same partitions as the other ones just described,)
runs out in a slope sidewise, through which the flour falling from the bolter accumulates at the side-
wall cc, Fig. 487, and thus runs easily through the opening d, into the bag f, as soon as the slide e is
shut up. As many as convenient are placed before a flour-partition, Fig. 486. They are put up and
taken away in the following simple manner At the sack-mouth i, beneath the opening d, on which
rests the sloping bottom b, are put in two screws hh. Their ends are crooked into hooks which grasp
the leather rim i of the sack. (See h beneath the opening d, Fig. 487.) About 3 or 5 feet above each
sack projects a rafter k, from which hangs down a thong l, with forceps m and n, to take hold of the rim
of the sack.
It may be finally remarked, that it has been tried to supplant the beaters above described, (see Fig.
484,) by another contrivance represented by Figs. 488 and 489 in side and front views. The chief part
consists of a thick steel button marked b, Fig. 488, fixed at the upper pivot of the bolter's axis b, Fig.
488. The steel button turns round on a strong and well-polished steel plate c, inserted into the pivot-
base d. Now the axis in turning round is by the three protuberances lifted up and down, and thus
constantly kept in a shaking motion. In this way the obstruction of the perforations of the bolting-
cloth is prevented as well as by the beaters.
The brush-bolter, or cylindrical dressing-machine, as it is styled, is in many mills used conjointly with
Ayton's improved bolting-machine, into which latter the grit and bran is brought after they have been
bolted in the dressing-machine.
Fig. 475 gives a side view of the common brush-bolter, while Figs. 476 and 477 represent an im-
proved machine of this kind in transverse and longitudinal section, several parts of which are illustrated
by Figs. 478 and 479, (on a large scale,) and 480 and 481.
The bolter, both of the common and improved machine, is cylindrical, covered by a bolting-cloth made
of wire-texture, and placed obliquely in the bolting-hutch. (See Figs. 475, 476, and 477.) The bolting-
cloth in Fig. 475 is directly fixed to the bolting-frame; but in Figs. 476 and 477 it is kept suspended
by long screw-bolts qq, fixed at the roof of the bolting-hutch. (See Figs. 476, 477, 480, and 481.) The
cylindrical sieve-frame of the common machine, Fig. 475, consists of staves bb, fixed round the disks
ec and at the felloes d. The interior periphery of this frame is covered with wire-gauze of different
fineness-the first number fixed at the upper end, and the less fine sorts following in succession, just in
the same way as has been mentioned.
The sieve-frame of the improved machine consists of two semi-cylinders, (see Figs. 477, 480, and
481,) whose side-boards e e are laid and screwed together, thus forming a full cylinder.
Within this cylindrical sieve is, exactly in its axis, placed the shaft ff, (made of wrought-iron in the
machines represented in Figs. 475 and 476,) which is provided with three disk-wheels g Fig. 477. On
the periphery of these wheels are put in eight brushes of hog's bristles h, (see Figs. 478 and 479,) in
the manner illustrated, not only by Fig. 477, but also by Fig. 478, where the wheel-periphery is marked
by gg, and the brushes by hh; while the outer circle signifies the inner periphery of the cylindrical
seve. The shaft ff. Fig. 477, is turned by the disk i, and during its rotation the brushes touch the inner
periphery of the cylindrical sieve as much as required, to prevent the obstruction of the perforations
by flour. In case the brushes should be worn, they can be screwed more forward by boxes k k, Fig. 478.
At the upper and lower end of the cylindrical sieve are the wooden rings l and m, Fig. 477, fastened
by means of screws. They are in the periphery somewhat notched, as may be seen by m, Fig. 481.
To the upper ring 1, Fig. 477 is tied, by means of a cord, the leather strip n, which is glued or nailed on
the bolting-hutch aa. By this arrangement the ground mass, coming out by the spout o, is taken up
here, and conveyed to the cylinder. The ring m, at the lower end, serves as a link between the parti-
tion-boards pp.
In order to establish equality in the brushing of the sieve, this latter, or the cylindrical bolter, is, by
means of four screw-bolts qq, kept in suspension, and may, according to circumstances, be wound up
and lowered, for which purpose the nuts are winged. The screw-bolts are at their ends provided with
hooks rr, Figa. 480 and 481, which take hold of two side-laths bb, Fig. 481, of the cylindrical frame of
the sieve. On the other hand the brush-cylinder, whose shaft ff rests on the sliding-rail 8, can also be
displaced, either up or down, by the nut of the screw t.
The hopper, which holds the ground grain, is marked by u, Fig. 477, and the moveable spout con-
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160
BOLTING-MILL.
m
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a
484.
475.
M
482.
485.
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a
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BOND.
161
nected with it by o. This spout is shaken by a nave v, fixed at the shaft ff, which beats during the
rotation against a tack at the bottom of the shoe. By the slide at w, the quantity of ground grain in
the shoe can be increased or decreased. The slide x, which in Fig. 477 is closed, is shut up in Fig. 476.
A cylindrical sieve or bolter of this kind is commonly covered with four or five different numbers of
wire-texture, through which the different qualities are bolted, and taken up by the corresponding par-
titions 1, 2, 3, 4, and 5, whence the flour is easily taken out through the side-openings, until then closed
by slides. The bran falls into the partition 6.
The fineness of the texture is commonly in the ratio of 64, 60, 56, 38, and 16 meshes to the square
inch. Experience has taught, that the best arrangement is to cover the frame from above, first with
gauze or texture of 60 meshes, and to follow in succession that of 64, 56, 38, and 16 meshes. The
gauze of 60 meshes furnishes as fine flour as that of 64, which is owing to the circumstance that the
fleur in the uppermost part of the bolter is not 80 much exposed to the influence of the brushes, and
that the finest quality of flour is more sticky or viscous than the coarser qualities.
By the rotation in one and the same direction, the bristles of the brushes must at last be bent to one
side, and thus lose their efficacy. To remedy this, an arrangement is made by which the brush-reel
turns alternately to the right and left. This is easily effected by double wheels or thong-disks.
A small brush-cylinder has been invented by James Murphy, of Zanesville, O, which is to be placed
at the outside of the above-described cylindrical sieve, that is, everywhere on its periphery brushed by
it. By this operation the obstruction of the meshes is completely prevented. Mr. Murphy uses thin
hoops and ribs of cast-iron for constructing the sieve-frames, instead of the above-described wooden
felloes and laths.
BOLTS, (iron.) The pieces of iron used for securing framing together, and much employed in timber-
work; they are formed of wrought-iron, either square or cylindrical, with a square head at one end,
and a screw and nut at the other; a plate of iron, termed a washer, being interposed between the
surface of the wood and the head and nut, to protect the former from damage during the process of
screwing up.
BOLSTERS. The pieces of timber used in the construction of the centres of arches, and running
across from one rib to another, for the purpose of supporting the voussoirs. A piece of timber, em-
ployed in a somewhat similar manner to a corbel, is also termed a bolster; which are much employed
in timber bridges.
BOND. The union or tie of the several stones or bricks forming a wall. The great principle in all bond
is to provide against settlements: the vertical joints of a course should, therefore, be exactly midway
between those below-in other words, break joint with them; and in no case should the joints of one
course be carried up over those of the one below it.
The bricks or stones lying lengthwise, in the longitudinal direction of the wall, are called stretchers;
and those placed lengthwise across the wall, headers.
490
491.
Old English Rond, or Block-bond.
Flemish Bond.
Bond may be described generally to be of three kinds. In English bond the courses are alternately
all headers and all stretchers, and when the backs of each course are laid alternately header and stretcher
it is called Flemish Bond; this description of tie is also known by the name of header and stretcher,
particularly in stone-work.
493.
492.
Cross-bond.
Combined Cross and Block bond.
The cross-bond-mostly used in Germany by bricklayers-differs from the old English or block
bond, by the change of the second stretcher-line, 80 that the joints of the second come in the middle of
the first, and the same position of stretchers comes back only every fifth line. This bond gives besides
a very neat appearance, and is therefore used wherever a nice building is to be erected. The strongest
tie is given to a wall by combining the block and cross-bond, so that the extrados is put up in cross-
bond, the intrados in block bond, as shown in the figure. The reason of it is, if a settling of the
wall happens, so that the joints open, all other bonds give only in the vertical, a crooked breaking
line; but this combined-bond requires a crooked breaking-line in the horizontal direction besidec ; it is
therefore applied where a neat appearance and great strength are required.
21
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162
BORING MACHINE.
BONES. See ANIMAL KINGDOM, materials from used in the mechanical and ornamental arts.
BORING MACHINE, Vertical: by Messrs. Nasmyth, Gaskell & Co. The many advantages derived
by this arrangement of a vertical boring machine over those where the work is placed in a horizontal
position, may perhaps be unknown to persons unacquainted with the general character of machinery
it may not be unadvisable to point out a few of the principal features showing the superiority of this
machire.
In the first place, the arrangements of its parts; the manner in which the cylinder is placed, namely,
its vertical position, thereby doing away entirely with all the injurious effects produced by the weight
of the body being planed or bored; thus obviating all tendency to distort its figure, which is the case
where the operation is performed by the horizontal system, and where the sides are bulged out from
the weight of the upper part; this may be better understood by forming a cylinder of thin paper, which
will be found to widen in the middle and assume an oval form from its own weight.
This alteration of form is found to be quite sensible when the cylinders are of large diameters.
Another great advantage of this system of vertical boring, is avoiding all risk of flexure in the boring-
bar, upon which the cutter wheel or head is fixed for carrying the boring-tools; this bar has a tendency
to bend down in the centre to a curve, instead of keeping a perfectly straight line, transferring the
figure assumed by the bar to the surface of the cylinder; but this will much depend both on its length
and diameter.
Another advantage of this machine is, that the cutters are kept clear of the borings, which fall to
the bottom of the cylinder as fast as they are cut. By this superior arrangement all these objections
are entirely removed, thus avoiding all the tendency gravity has in altering the trueness of the cylinder
or the bar; added to these, the power requisite to bore the cylinder is found to be much less than in
those placed horizontally, a very desirable object in a large establishment.
A short description of its several parts will enable the reader more fully to understand the advanta-
ges already alluded to.
Fig. 494 represents a cross-section of this machine, and Fig. 497 a plan showing its position in a
corner of the building where it is placed. In these two views it will be seen that the driving part of
the machinery is situated below the ground-line on suitably strong foundations, in which it is enclosed.
These parts are rendered accessible by the steps t, which are found to be necessary in cases where the
machinery is likely to get out of order, a precaution never to be neglected.
The two riggers k k receive their motion from the main shaft by means of a leather strap: one of
these runs loose on the shaft, and the strap is thrown on it when the machine is not at work; this is
done at pleasure with the greatest possible facility; by a bevel-wheel and pinion j, it is then conveyed
through the shaft i to the endless worm n, working in a large worm-wheel o, which is fixed on the great
vertical boring-bar a, whereby a very easy motion is obtained, and all jerks avoided. It will be seen
by the series of wheels in Fig. 497, how much the speed of the boring-bar is reduced. The shaft i
is placed at an angle, and works in a bearing or plummer block and a step h, both of these being made
of brass.
The vertical bar is made in two parts a and c, the upper one a for carrying the cutter-head or boring-
wheel r, while to the lower one is connected the driving apparatus; they are coupled together by the
upper one resting, as is shown in Fig. 496, in a socket on the top of the lower one; a steel key l is
then driven in, which entirely prevents it from turning; the toe of the bar c rests in a step or socket
shown by Fig. 498; the entire weight of this bar and its appendages is thrown on the hardened cast-steel
disks s, which are constantly kept supplied with oil. Both extremities of the bar c are rendered ad-
justable to the greatest possible accuracy by means of the small set-screws qq, Figs. 496 and 498,
which, by being tightened, press against the conical brass segments, the upper one forming part of the
great base or floor-plate b, which is materially strengthened by six strong ribs on its under side. The
cross-beam g is well fitted to the sockets f, built into the wall of the building, where they are bolted by
strong bolts, Figs. 494, 495, and 497. It has an additional stay in the bolt u.
There are four standards or supports, dd, Fig. 494, for carrying the cylinder to be bored, which can
be altered to any convenient position by unscrewing the bolts which fix them to the base-plate. After
the cylinder has been properly placed in its right position, it is fixed to these supports by clamps e and
bolts; and thus rendered quite immoveable.
In the boring-bar a is a deep socket m, Fig. 494, which allows the bar to slide up and down by
means of the screw P and the nut 1; upon the lower side of this socket is a flange m, upon which the
cutter-head or wheel r rests, receiving its motion from the bar by means of a nut, answering both the
purpose of nut and key. By the different arrangements of the sun and planet motion of the wheels on
the upper part of the bar, any degree of motion can be given to the screw for the descent of the cutter-
wheel. After the cylinder has been once bored through, the cutter-wheel is raised by means of a small
crane, and the chains, Fig. 495, and by the peculiar arrangement of the nut l in the socket m, the cutter-
wheel can be drawn up the cylinder without turning the screw p, as it leaves the nut behind, which is
afterwards screwed up, there being no other weight to raise but that of the nut. The cutters are then
set afresh to the new or finishing cut, after which the cylinder may be considered perfectly true. The
position occupied by the crane enables the cylinder to be placed, and the bar lifted in and out with
most perfect case; while the space occupied by this machine is very small compared with those where
the work is performed horizontally it is, however, important that the base-plate b should be well
secured to the foundations by strong bolts.
The speed of this machine may very easily be varied, by having different-sized riggers or pulleys on
the driving-shaft which conveys the motion to the riggers kk, Figs. 494 and 497.
BORING MACHINE, Great. By Messrs. Nasmyth, Gaskell and Co. The machine represented by
Fig. 499 is, with few exceptions, the same as that last described, where the cylinder to be bored is
placed in a vertical position, whereby numerous advantages are derived, as already explained.
The motion is communicated by the driving-pulley c to a bevel pinion working the bevel-wheel d;
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BORING MACHINE.
163
495.
494.
9
I
Elevation
Plan
496.
Section
m
20
m
T
a
c
d
410
c
Section
498.
2
a
######
497.
#
nn
Lo
un
6
1
.
Boring-bar.
Cross-beam.
R Screw working in wheel a
b
Foundation or base plate.
Step or bearing for driving-shaft.
0
Screw-wheel.
c Socket and lower part of upright
i Driving-shaft.
P
Screw for regulating drilling-bar.
bar.
Bevel-wheel and pinion.
q
Adjusting-screws.
d Movemble supports for carrying cyl-
7
Driving riggers.
r
Boring-wheel.
inder to be bored.
1 Keys and nut.
8
Steel disks or pivots.
e
Clamps.
17.
Socket upon which the cutter-wheel
t
Steps.
f
Socket for carrying the beam 8.
rests.
M Tie bar.
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164
BORING MACHINE.
the shaft on which this wheel is fixed, has on its opposite end a worm for communicating the motion
through the worm-wheel to the upright shaft f and boring-bar a, having on its circumference the grooves
a' in which the cutter-head is moveable, sliding up and down according to the progress of the work
k is a tool-carrier fixed to the cutter-head. The foundation plate h forms a bearing for the upright
shaft, the lower end of which rests in the step g, while the cylinder l is secured by the clamps jj to the
supports ii fixed to the foundation plate. These parts are in every respect similar to the boring ma-
chine shown by Fig. 494, by which they are more fully described.
Two strong piers of masonry m' support the entablature m, (for carrying the self-acting apparatus for
raising and lowering the cutter-head b,) to which it is bolted by strong holding-down bolts m'. This
apparatus consists of a rack n worked by a pinion, the motion being transmitted from a trullion-wheel
through two spur-wheels and pinions o. The whole of this upper machinery revolves with the boring-
bar, with the exception of the internal wheel or screwed hoop p; the consequence of which is, the small
trullion-wheel is made to turn on its axis by the thread of the wheel p in which it works, and thereby
ultimately raises the cutter-head b, the two side-slings connecting it to the upper frame q', to which is
fixed the rack n.
This machine is of the largest dimensions, and was made for the purpose of boring the large cylin-
ders, 10 feet in diameter, for the Great Western Steam Navigation Company's vessel the Mammoth,
at their works at Bristol
499.
i
l
a Upright boring-bar.
i Supports for carrying the cylinder to
P Internal screw-wheel on the upper
Ь Cutter-head working up and down
be bored.
[ports i.
part of cutter-head conveying the
in the three V's a'.
j Clamps for fixing cylinder to sup-
self-acting raising motion to it, by
c Driving-pulleys fixed on shaft c'.
k Tool-carrier fixed to cutter-head.
the trullion-wheel and spur-wheels
d Bevel-wheel and pinion for convey-
1 Cylinder being bored.
and pinions #.
ing the motion at right angles.
Entablature for guiding the upper
9
Side-slings which convey the eleva-
e Worm-wheel.
part of bar, boll 1 to walls m by
ting or cut-feeding motion from the
Upright shaft for working boring-bar.
bolts m".
rack n down to the cutter-head b.
Step for shaft.
R Rack and pinion for raising the cut-
All revolves with the boring-bar
Foundation plate and boring-box
ter-head, worked by spur-wheels
except the internal screw-wheel or
bearing, tightened by conical pieces
and pinions o.
screwed hoop p, which is stationa-
and scrows k'.
0 Spur-wheels and pinions.
ry, being bolted to the entablature.
BORING MACHINE, Vertical. By Messrs. Benjamin Hick and Son, Bolton. By this combination
of three distinct machines, the following different operations may be performed, viz. boring, drilling, and
face-grinding: it is so contrived that the entablature b, supported by the four columns a a a a, carries
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BORING MACHINE.
165
500.
6
3
B
A
C
W
0
22
n
n
a Columns for supporting the entabla-
to be bored moveable in grooves
cutters) for giving it the feod or
b Entablature.
[ture b.
in the foundation plate n.
advancing motion.
c Boring-bar of large machine.
i Clamps or Caps for securing the cyl-
I Second floor of the building, and on
d Driving-pulleys worked by leather
inder to the supports h.
which is placed 8 crane for raising
strap d.
j
Circular frame or ring for steadying
or lowering the boring-bar when a
e Bevel-wheel and pinion conveying
the cylinder, which is adjusted to
cylinder has to be placed or re-
the motion to the upright shaft f
its proper place by the set-screws
moved.
through the column a.
this frame can be raised or lowered,
- Footstep for boring-bar.
f
Upright shaft working in footstep f'.
and is secured by bolts fitted into
n
Foundation plate.
8 Spur pinion and wheel for working
grooves in the back of columns a.
o
Framing and beds of the side ma-
the boring-bar c.
k Racks and wheels attached to the
chines on which the V slides o'
h Supports for carrying the cylinder
boring-block (containing the steel
move.
501.
O
PO
P Travelling tables for carrying the
t Guide-frame for boring-bar of ma-
ported by the two bracket car-
work to be bored, &c.
chine B, fixed between the two
riages x" u".
9 Driving-pulleys for machines B and
columns a a.
D Chain pulleys and weight for raising
C, worked by straps d.
a Reversed cones, strap-shaft, and bev-
the boring-bar u' supported by the
r
Cross-shaft, levers, and links, for oc-
el-wheels, for giving the feeding
two brackets o' v'.
casionally raising the grinding-plate
motion to the upright boring-bar %
to Cylinder being bored.
r, of machine C.
by means of the screw x" attached
x Crank being bored.
s Cross-frame for carrying the brackets
to its upper end. The shaft is sup-
y Piston having its face ground.
' s' for supporting the shaft T.
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166
BORING TOOLS.
the upper parts of the three different machines, consisting of the requisite driving machinery for com-
municating to them their respective motions.
That in the centre, A, is a vertical boring machine for boring cylinders of large diameters, which are
fixed in the usual way on the six moveable supports h by the clamps i; in addition to which it is ren-
dered perfectly steady by the circular frame or ring j, sliding up and down in grooves on the back of
the two middle columns, the adjusting-screws j being tightened when the cylinder is properly placed
under the centre of the boring-bar c, which receives its motion from the leather strap and pulleys d,
whence it is conveyed through the bevel pinion and wheel e on the upright shaft f, upon which is also
keyed the spur-pinion for driving the wheel g fixed to the lower part of the boring-bar c, and working
in the step m; the rack and wheel k gives the cutter-head the requisite feed while boring out the
cylinder. The six supports h are made to slide in grooves on the foundation plate n, according to the
different diameters of the cylinders being operated upon; these, when properly placed, are bolted to
the plate n.
The second machine, B, is a vertical drilling and boring machine for work of smaller dimensions than
the machine A. It is shown in the drawing boring out the centre of a crank x, fixed to the travelling
table p, and slides on V's on the frame o', which has also a motion at right angles, on the bed o fixed
to the foundation plate. The drilling-bar u' is lowered by the screw u" according to the feed, its mo-
tion being conveyed to it from the pulley q and strap q' to a spur-wheel and pinion not shown in the
drawing; the pinion is on the same spindle as the pulley, and the wheel on that of the reversed cone u,
by which it is carried to the square-threaded screw 14" by two pairs of small bevel-wheels u, fixed on
a horizontal spindle and working in suitable bearings on the carriages 26" u". The apparatus for
raising the drilling-bar, Fig. 500, consists simply of two small chains fixed to the bar 26' and working
round the pulleys, its opposite end being attached to a weight v.
The third machine C, is for the purpose of grinding up the faces of rings for metallic pistons, conical
valves, &c.; the travelling table p of this machine is in every respect similar to that of B, and upon it is
placed the piston y to be ground; the upright rod, receiving its motion from the pulley and strap q', is
kept in a vertical position by the cross-frame 8, while the shaft r and grinding-plate are connected to
the lower end of the rod, and are occasionally raised for examining the surface being ground.
The different motions given to these machines are quite independent the one of the other, by which
means any one of them can be worked separately. The whole is placed on a suitable strong founda-
tion of stone. After the large cylinder is bored, it is raised from its position by a crane placed on the
floor above.
BORING : and extraction of winding tools
-Jumpers Widening -Lengthening of
extraction of broken rods ;-accidents;-spring-bar;-head-piece;-clan;--plaform. See RAILWAY
ENGINEERING.
BORING TOOLS. The process of boring holes may be viewed as an inversion of that of turning:
generally the work remains at rest, and the tool is revolved and advanced. Many of the boring and
drilling tools have angular points, which serve alike for the removal of the material, and the guidance
of the instrument; others have blunt guides of various kinds for directing them, whilst the cutting is
performed by the end of the tool.
Commencing as usual with the tools for wood, the brad-awl, Fig. 502, may be noticed as the most
simple of its kind; it is a cylindrical wire with a chisel edge, which rather displaces than removes the
material; it is sometimes sharpened with three facets as a triangular prism. The awl, Fig. 503, used
by the wire-workers, is less disposed to split the wood; it is square and sharp on all four edges, and
tapers off very gradually until near the point, where the sides meet rather more abruptly.
The generality of the boring instruments used in carpentry are fluted, like reeds split in two parts,
to give room for the shavings, and they are sharpened in various ways, as shown by Figs. 504 to 508.
Fig. 504 is known as the shell-bit, and also as the
gouge-bit, or quill-bit; it is sharpened at the end like
502.
503.
504.
505.
506.
507.
508.
a gouge, and when revolved it shears the fibres
around the margin of the hole, and removes the
wood almost as a solid core. The shell-bits are in
very general use, and when made very small, they
are used for boring the holes in some brushes.
Fig. 505, the spoon-bit, is generally bent up at
the end to make a taper point, terminating on the
diametrical line; it acts something after the manner
of a common pointed drill, except that it possesses
the keen edge suitable for wood. The spoon-bit is
in very common use; the coopers' dowel-bit, and the
table-bit, for making the holes for the wooden joints
of tables, are of this kind. Occasionally the end is
bent in a semicircular form; such are called duck-
nose-bits from their resemblance, and also brush-
bits from their use; the diameter of the hole con-
tinues undiminished for a greater depth than with the pointed spoon-bit.
The nose-bit, Fig. 506, called also the slit-nose-bit, and auger-bit, is slit up a small distance near the
centre, and the larger piece of the end is then bent up nearly at right angles to the shaft, so as to act
like a paring-chisel; and the corner of the reed. near the nose, also cuts slightly. The form of the
nose-bit, which is very nearly a diminutive of the shell-auger, Fig. 507, is better seen in the latter
instrument, in which the transverse cutter lies still more nearly at right angles, and is distinctly curved
on the edge instead of radial. The augers are sometimes made three inches diameter, and upwards,
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BORING TOOLS.
167
and with long removeable shanks, for the purpose of boring wooden pump-barrels; they are then called
pump-bits.
There is some little uncertainty of the nose-bits entering exactly at any required spot, unless a
small commencement is previously made with another instrument, as a spoon-bit, a gouge, a brad-awl,
a centre-punch, or some other tool; with augers a preparatory hole is invariably made, either with a
gouge, or with a centre-bit exactly of the size of the auger. When the nose-bits are used for making
the holes in sash bars, for the wooden pins or dowels, the bit is made exactly parallel, and it has a
square brass socket which fits the bit; so that the work and socket being fixed in their respective
situations, the guide-principle is perfectly applied. A "guide-tube" built up as a tripod, which the
workman steadies with his foot, has been recently applied by Mr. Charles May, of Ipswich, for boring
the auger-holes in railway sleepers exactly perpendicular.
The gimlet, Fig. 508, is also a fluted tool, but it terminates in a sharp worm or screw, beginning as a
point and extending to the full diameter of the tool, which is drawn by the screw into the wood. The
principal part of the cutting is done by the angular corner intermediate between the worm and shell,
which acts much like the auger. The gimlet is worked until the shell is full of wood, when it is unwound
and withdrawn to empty it.
The centre-bit, Fig. 509, shown in three views, is a very beautiful instrument; it consists of three
parts, a centre-point or pin, filed triangularly, which serves as a guide for position; a thin shearing-
point or nicker, that cuts through the fibres like the point of a knife; and a broad chisel-edge or cutter,
placed obliquely to pare up the wood within the circle marked out by the point. The cutter shoul 1
have both a little less radius and less length than the nicker, upon the keen edge of which last the
correct action of the tool principally depends.
Many variations are made from the ordinary centre-bit, Fig.
509.
510.
11.
509; sometimes the centre-point is enlarged into a stout cylin-
drical plug, so that it may exactly fill a hole previously made,
and cut out a cylindrical countersink around the same, as for
the head of a screw-bolt. This tool, known as the plug centre
bit, is much used in making frames and furniture, held together
a
by screw-bolts. Similar tools, but with loose cutters inserted
in a diametrical mortise, in a stout shaft, are also used in ship-
building for inlaying the heads of bolts and washers, in the
timbers and planking.
b
The wine-cooper's centre-bit is very short, and is enlarged
behind into a cone, 80 that immediately a full cask has been
bored, the cone plugs up the hole until the tap is inserted. The
centre-bit deprived of its chisel-edge, or possessing only the pin
and nicker, is called a button-tool; it is used for boring and
cutting out, at one process, the little leather disks or buttons,
which serve as nuts for the screwed wires in the mechanism connected with the keys of the organ and
pianoforte.
The expanding centre-bit, shown on a much smaller scale in Fig. 512, is a very useful instrument; it
has a central stem with a conical point, and across the end of the stem is fitted a transverse bar
adjustable for radius. When the latter carries only a lancet-shaped cutter it is
used for making the margins of circular recesses, and also for cutting out disks of
wood and thin materials generally; when, as in Mr. James Stone's modification, the
512.
expanding centre-bit has two shearing-points or nickers, and one chisel-formed
cutter, it serves for making grooves for inlaying rings of metal or wood in cabinet-
work, and other purposes.
The above twols being generally used for woods of the softer kinds, and the
plankway of the grain, the shearing-point and oblique chisel of the centre-bit, Fig.
509, are constantly retained, but the corresponding tools used for the hard woods
assume the characters of the hard-wood tools generally. For instance, a, Fig. 510,
has a square point, also two cutting edges, which are nearly diametrical, and sharpened with a single
chamfer at about 60 degrees; this is the ordinary drill used for boring the finger-holes in flutes an 1
clarionets, which are afterwards chamfered on the inner side with a stout knife, the edge of which
measures about 50 degrees. The key-holes are first scored with the cup-key tool, b, and then drilled,
the tools a and b being represented of corresponding sizes, and forming between them the annular
ridge which indents the leather of the valve or key.
When a, Fig. 510, is made exactly parallel and sharpened up the sides, it cuts hard mahogany very
cleanly in all directions of the grain, and is used for drilling the various holes in the small machinery of
pianofortes; this drill (and also the last two) is put in motion in the lathe; and in Fig. 511, the lathe-
drill for hard woods, called by the French langue de carpe, the centre-point and the two sides melt into
an easy curve, which is sharpened all the way round and a little beyond its largest part.
Various tools for boring wood have been made with spiral stems, in order that the shavings may be
enabled to ascend the hollow worm, and thereby save the trouble of so frequently withdrawing the bit.
For example, the shaft of Fig. 513, the single-lip auger, is forged as a half-round bar, nearly as in the
section above; it is then coiled into an open spiral with the flat side outwards, to constitute the cylin-
drical surface, and the end is formed almost the same as that of the shell-auger, Fig. 507. The tristed
gimlet, Fig. 514, is made with a conical shaft, around which is filed a half-round groove, the one edge of
which becomes thereby sharpened, SO as gradually to enlarge the hole after the first penetration of the
worm, which, from being smaller than in the common gimlet, acts with less risk of splitting.
The ordinary screw-auger, Fig. 515, is forged as a parallel blade of steel, (seen in Fig. 516, which
also refers to 515 and 517;) it is twisted red-hot, the end terminates in a worm by which the auger IS
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BORING TOOLS.
gradually drawn into the work, as in the gimlet, and the two angles or lips are sharpened to cut at the
extreme ends, and a little up the sides also.
The same kind of shaft is sometimes made as in Fig. 516, with a plain conical point, with two scoring
cutters and two chisel edges, which receive their obliquity from the slope of the worm it is as it were
a double centre-bit, or one with two lips grafted on a spiral shaft. The same shaft has been also made,
as in Fig. 517. with a common drill-point, and proposed for metal, but this seems scarcely called for ;
513.
514.
515.
516.
517.
518.
519.
520.
but it is in this form very effective in Hunter's patent stone-boring machine, intended for stones not
harder than sandstones; the drill is worked by a cross, guided by a tube, and forced in by a screw cut
upon the shaft carrying the drill; so that the stone is not ground to powder, but cast off in flakes with
very little injury to the drill.
Another screw-auger, which is perhaps the most general after the double-lipped screw-auger, Fig.
515, is known as the American screw-auger, and is shown in Fig. 518; this has a cylindrical shaft,
around which is brazed a single fin or rib; the end is filed into a worm as usual, and immediately be-
hind the worm a small diametrical mortise is formed for the reception of a detached cutter, which ex-
actly resembles the nicking-point and chisel-edge of the centre-bit; it may be called a centre-bit for
deep holes. The parts are shown detached in Fig. 519. The loose cutter is kept central by its square
notch, embracing the central shaft of the auger; it is fixed by a wedge driven in behind, and the
chisel-edge rests against the spiral worm. Spare cutters are added in case of accident, and should the
screw be broken off, a new screw and mortise may be made by depriving the instrument of 80 much
of its length. This instrument will be found on trial extremely effective; and on account of the great
space allowed for the shavings, they are delivered perfectly, until the worm is buried a small distance
beneath the surface of the hole.
The Americans have also invented an auger, thoroughly applicable to producing square holes, and
those of other forms: the tool consists of a steel tube, of the width of the hole, the end of the tube is
sharpened from within, with the corners in advance, or with four hollowed edges. In the centre of the
square tube works a screw-auger, the thread of which projects a little beyond the end of the tube. 80
as first to penetrate the wood, and then to drag after it the sheath, and thus complete the hole at one
process; the removed shavings making their escape up the worm and through the tube. For boring
long mortises, two or more square augers are to be placed side by side, but they must necessarily be
worked one at a time. The tools Figs. 513 to 520 are American.
The screw-auger acts as a hollow taper-bit or rimmer, and the screw-form point and shaft
assist in drawing it into the wood; but the instrument must pass entirely through for making cylin-
drical holes.
The most usual of the modes of giving motion to the various kinds of boring bits, is by the ordinary
carpenter's brace with a crank-formed shaft. The instrument is made in wood or metal, and at the one
extremity has a metal socket called the pad, with a taper square hole, and a spring catch used for
retaining the drills in the brace when they are withdrawn from the work; and at the other it has a swiv-
elled head or shield, which is pressed forward horizontally by the chest of the workman; or when used
vertically, by the left hand, which is then commonly placed
against the forehead.
The ordinary carpenter's brace is too familiarly known to
521.
require further description, but it sometimes happens, that in
(orners and other places there is not room to swing round the
handle; the angle brace, Fig. 521, is then convenient. It is
made entirely of metal, with a pair of bevel pinions, and a
winch-handle that is placed on the axis of one of these, at
various distances from the centre, according to the power or
velocity required. Sometimes the bevel-wheel attached to
the winch-handle is three or four times the diameter of
the pinion on the drill; this gives greater speed, but less
power.
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The augers, which from their increased size require more power, are moved by transverse handles
some augers are made with shanks, and are riveted into the handles just like the gimlet; occasionally
the handle has a socket or pad, for receiving several augers, but the most common mode is to form the
end of the shaft into a ring or eye, through which the transverse handle is tightly driven. The brad-
awls, and occasionally the other tools requiring but slight force, are fitted in straight handles; many of
the smaller tools are attached to the lathe-mandrel by means of chucks, and the work is pressed against
them, either by the hand, or by a screw, a slide, or other contrivance; Figs. 510 and 511 are always
thus applied.
Drills for metal, used by hand-The frequent necessity in metal works, for the operation of drilling
holes, which are required of all sizes and various degrees of accuracy, has led to so very great a variety
of modes of performing the process, that it is difficult to arrange with much order the more important
of these methods and apparatus.
The ordinary piercing drills for metal do not present quite so much variety as the wood drills ra-
cently described. The drills for metal are mostly pointed; they consequently make conical holes, which
cause the point of the drill to pursue the original line, and eventually to produce the cylindrical hole.
The comparative feebleness of the drill-bow limits the size of the drills employed with it to about one-
quarter of an inch in diameter; but as some of the tools used with the bow, agree in kind with those
of much larger dimensions, it will be convenient to consider as one group, the forms of the edges of those
drills which cut when moved in either direction.
Figs. 522, 523, and 524, represent, of their largest sizes, the usual forms of drills proper for the re-
ciprocating motion of the drill-bow, because their cutting edges being situated on the line of the axis,
and chamfered on each side, they cut, or rather scrape, with equal facility in both directions of motion.
522.
523.
524.
525.
526.
527.
Fig. 522 is the ordinary double-cutting drill; the two facets forming each edge meet at an angle of
about 50 to 70 degrees, and the two edges forming the point meet at about 80 to 100; but the watch-
makers, who constantly employ this kind of drill, sometimes make the end as obtuse as an angle of
about 120 degrees; the point does not then protrude through their thin works, long before the comple-
tion of the hole. Fig. 523, with two circular chamfers, bores cast-iron more rapidly than any other re-
ciprocating drill, but it requires an entry to be first made with a pointed drill; by some, this kind is also
preferred for wrought-iron and steel. The flat-ended drill, Fig. 524, is used for flattening the bottoms
of holes. Fig. 525 is a duplex expanding drill, used by the cutlers for inlaying the little plates of metal
in knife-handles; the ends are drawn full size.
Fig. 526 is also a double-cutting drill; the cylindrical wire is filed to the diametrical line, and the end
is formed with two facets. This tool has the advantage of retaining the same diameter when it is sharp-
ened; it is sometimes called the Swiss drill, and was employed by M. Le Rivière, for making the nu-
merous small holes in the delicate punching machinery for manufacturing perforated sheets of metal
and pasteboard; these drills are sometimes made either semicircular or flat at the extremity, and as
they are commonly employed in the lathe, they will be hereafter further noticed.
The square countersink, Fig. 527, is also used with the drill-bow; it is made cylindrical, and pierced
for the reception of a small central pin, after which it is sharpened to a chisel-edge, as shown. This
countersink is in some measure a diminutive of the pin-drills, Figs. 534 to 537, and occasionally circular
collars are fitted on the pin for its temporary enlargement, or around the larger part to serve as a stop,
and limit the depth to which the countersink is allowed to penetrate, for inlaying the heads of screws.
The pin is removed when the instrument is sharpened.
By way of comparison with the double-cutting drills, the ordinary forms of those which only cut in
one direction, are shown in Figs. 528, 529, and 530. Fig. 528 is the common single-cutting drill, for the
drill-bow, brace, and lathe; the point, as usual, is nearly a rectangle, but is formed by only two facets,
which meet the sides at about 80° to 85° and therefore lie very nearly in contact with the extremity
of the hole operated upon, thus strictly agreeing with the form of the turning tools for brass. Fig. 529
is a similar drill, particularly suitable for horn, tortoise-shell, and substances liable to agglutinate and
clog the drill; the chamfers are rather more acute, and are continued around the edge behind its largest
diameter, so that if needful, the drill may also cut its way out of the hole.
Fig. 530, although never used with the drill-bow, nor of so small a size as in the wood-cut, is added
to show how completely the drill proper for iron, follows the character of the turning tools for that
metal; the flute or hollow filed behind the edge, gives the hook-formed acute edge required in this tool,
which is in other respects like Fig. 528; the form proper for the cutting edge is shown more distinctly
in the diagram a, Fig. 534.
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Care should always be taken to have a proportional degree of strength in the shafts of the drills,
otherwise they tremble and chatter when at work, or they occasionally twist off in the neck; the point
should be also ground exactly central, 80 that both edges may be cut. As a guide for the proportional
thickness of the point, it may measure at b, Fig. 531, the base of the cone, about one-fifth the diameter
of the hole; and at p, the point, about one-cighth, for easier penetration: but the fluted drills are made
nearly of the same thickness at the point and base.
528.
529.
530.
531.
532.
533.
B
p
In all the drills previously described, except Fig. 526, the size of the point is lessened each time of
sharpening; but to avoid this loss of size, a small part is often made parallel, as shown in Fig. 531. In
Fig. 532, this mode is extended by making the drill with a cylindrical lump, SO as to fill the hole; this
is called the recentering-drill. It is used for commencing a small hole in a flat-bottomed cylindrical
cavity or else, in rotation with the common piercing-drill, and the half-round bit, in drilling small and
very deep holes in the lathe. Fig. 532 may be also considered to resemble the stop-drill, upon which
a solid lump or shoulder is formed, or a collar is temporarily attached by a side-screw, for limiting the
depth to which the tool can penetrate the work.
Fig. 533, the cone-countersink, may be viewed as a multiplication of the common single-cutting drill
Sometimes, however, the tool is filed with four equidistant radial furrows, directly upon the axis, and
with several intermediate parallel furrows sweeping at an angle around the cone. This makes a more
even distribution of the teeth than when all are radial as in the figure, and it is always used in the
spherical cutters or countersinks known as cherries, which are used in making bullet-moulds.
On comparison, it may be said, the single-chamfered drill, Fig. 528, cuts more quickly than the double-
chamfered, Fig. 522, but that the former is also more disposed of the two to swerve or run from its
intended position. In using the double-cutting drills, it is also necessary to drill the holes at once to
their full sizes, as otherwise the thin edges of these tools stick abruptly into the metal, and are liable
534.
535.
536.
537.
a
to produce jagged or groovy surfaces, which destroy the circularity of the holes; the necessity for drill-
ing the entire hole at once, joined to the feebleness of the drill-bow, limits the size of these drills.
In using the single-chamfered drills it is customary, and on several accounts desirable, to make large
holes by a series of two or more drills; first the run of the drill is in a measure proportioned to its
diameter, therefore the small tool departs less from its intended path, and a central hole once obtained,
it is followed, with little after-risk, by the single-cutting drill, which is less penetrative. This mode
likewise throws out of action the less favorable part of the drill near the point, and which in large drills
is necessarily thick and obtuse the subdivision of the work enables a comparatively small power to be
used for drilling large holes, and also presents the choice of the velocity best suited to each progressive
diameter operated upon. But where sufficient power can be obtained, it is generally more judicious to
enlarge the holes previously made with the pointed-drills, by some of the group of pin-drills, Figs. 534
to 537, in which the guide-principle is very perfectly employed: they present a close analogy to the
plug centre-bit and the expanding centre bit used in carpentry.
The ordinary pin-drill, Fig. 534, is employed for making countersinks for the heads of screw-bolts in
laid flush with the surface, and also for enlarging holes commenced with pointed drills, by a cut parallel
with the surface; the pin-drill is also particularly suited to thin materials, as the point of the ordinary
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drill would soon pierce through, and leave the guidance less certain. When this tool is used for iron it
is fluted as usual, and a represents the form of the one edge separately.
Fig. 535 is a pin-drill, principally used for cutting out large holes in cast-iron and other plates. In
this case the narrow cutter removes a ring of metal, which is, of course, a less laborious process than
cutting the hole into shavings. When this drill is applied from both sides it may be used for plates
half an inch and upwards in thickness; as, should not the tool penetrate the whole of the way through,
the piece may be broken out, and the rough edges cleaned with a file or a broach.
Fig. 536 is a tool commonly used for drilling the tube-plates for receiving the tubes of locomotive-
boilers: the material is about t inch thick, and the holes 14 diameter. The loose cutter a is fitted in a
transverse mortise, and secured by a wedge; it admits of being several times ground before the notch
which guides the blade for centrality is obliterated. Fig. 587 is somewhat similar to the last two, but
is principally intended for sinking grooves and when the tool is figured, as shown by the dotted line,
it may be used for cutting bosses and mouldings on parts of work not otherwise accessible.
Many ingenious contrivances have been made to insure the dimensions and angles of tools being ex-
actly retained. In this class may be placed Mr. Roberts' pin-drill, Figs. 538 and 539; in action it re-
sembles the fluted pin-drill, Fig. 534,
but the iron stock is much heavier, and
538.
539.
is attached to the drilling-machine by
the square tang; the stock has two
grooves at an angle of about 10 de-
grees with the axis, and rather deeper
behind than in front. Two steel cut-
ters, or nearly parallel blades, repre-
sented black. are laid in the groves;
they are fixed by the ring and two set-
screws 88, and are advanced, as they become worn away, by two adjusting-screws aa, (only one seen,)
placed at the angle of 10 degrees through the second ring; which, for the convenience of construction,
is screwed upon the drill-shaft just beyond the square tang whereby it is attached to the drilling-
machine. The cutters are ground at the extreme ends, but they also require an occasional touch on the
oilstone to restore the keenness of the outer angles, which become somewhat rounded by the friction.
The diminution from the trifling exterior sharpening, is allowed for by the slightly taper form of the
blades.
The process of drilling generally gives rise to more friction than that of turning, and the same meth-
ods of lubrication are used, but rather more commonly and plentifully; thus oil is used for the generality
of metals-or from economy, soap and water; milk is the most proper for copper, gold, and silver; and
cast-iron and brass are usually drilled without lubrication. For all the above-named metals, and for
alloys of similar degrees of hardness, the common-pointed steel drills are generally used but for lead
and very soft alloys, the carpenters' spoon-bits and nose-bits are usually employed, with water. For
hardened steel, and hard crystalline substances, copper or soft-iron drills, such as Figs. 529 or 530, sup-
plied with emery-powder and oil, are needed; or the diamond drill-points, Figs. 531, 532, and 533, are
used for hardened steel, with oil alone.
Having considered the most general forms of the cutting parts of drills, we will proceed to explain
the modes in which they are put in action by hand-power, beginning with those for the smallest diame-
ters, and proceeding gradually to the largest.
Methods of Working Drills by Hand smallest holes are those required in watch-work,
and the general form of the drill is shown on a large scale in Fig. 540; it is made of a piece of steel
wire, which is tapered off at the one end,
flattened with the hammer, and then filed
540.
up in the form shown at large in Fig. 522;
lastly, it is hardened in the candle. The
re urse end of the instrument is made into
a conical point, and is also hardened; near this end is attached a little brass sheave for the line of the
drill-bow, which, in watchmaking, is sometimes a fine horsehair, stretched by a piece of whalebone of
about the size of a goose's quill stripped of its feather.
The watchmaker holds most of his works in the fingers, both for fear of crushing them with the
table-vice, and also that he may the more sensibly feel his operations; drilling is likewise performed
by him in the same manner. Having passed the bowstring around the pulley in a single loop, (or with
a round turn.) the centre of the drill is inserted in one of the small centre-holes in the sides of the table-
vice, and the point of the drill is placed in the mark or cavity made in the work by the centre-punch;
the object is then pressed forward with the right hand, whilst the bow is moved with the left.
Clockmakers, and artisans in works of similar scale, fix the object in the tail-vice, and use drills, such
as Fig. 540, but often larger and longer; they are pressed forward by the chest, which is defended from
injury by the breastplate, namely, a piece of wood or metal about the size of the hand. in the middle
of which is a plate of steel, with centre holes for the drill. The breastplate is sometimes strapped
round the waist, but is more usually supported with the left hand, the fingers of which are ready to
catch the drill should it accidentally slip out of the centre.
As the drill gets larger the bow is proportionably increased in stiffness, and eventually becomes the
half of a solid cone, about one inch in diameter at the larger end, and 30 inches long; the catgut
string is sometimes nearly an eighth of an inch in diameter, or is replaced by a leather thong. The
string is attached to the smaller end of the bow by a loop and notch, much the same as in the archery-
bow, and is passed through a hole at the larger end, and made fast with a knot; the surplus length is
wound round the cane, and the cord finally passes through a notch at the end, which prevents it from
uncoiling.
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Steel bows are also occasionally used these are made something like a fencing-foil, but with a hook
at the end for the knot or loop of the cord, and with a ferrule or a ratchet, around which the spare cord
is wound. Some variations also are made in the sheaves of the large drills; sometimes they are cylin-
drical with a fillet at each end; this is desirable, as the cord necessarily lies on the sheave at an angle,
in fact in the path of a screw; it pursues that path, and with the reciprocation of the drill-bow the
cord traverses, or screws backwards and forwards upon the sheave, but is prevented from sliding off by
the fillet. Occasionally, indeed, the cylindrical sheave is cut with a screw coarse enough to receive the
cord, which may then make three or four coils for increased purchase, and have its natural screw-like
run without any fretting whatever; but this is only desirable when the holes are large and the drill is
almost constantly used, as it is tedious to wind on the cord for each individual hole. The structure of
the bows, breastplates, and pulleys, although often varied, is sufficiently familiar to be understood
without figures.
When the shaft of the drill is moderately long, the workman can readily observe if the drill is square
with the work as regards the horizontal plane; and to remove the necessity for the observation of an
assistant as to the vertical plane, a trifling weight is sometimes suspended from the drill-shaft by a
metal ring or hook; the joggling motion shifts the weight to the lower extremity the tool is only hori-
zontal when the weight remains central.
In many cases, the necessity for repeating the shaft and pulley of the drill is avoided, by the em-
ployment of holders of various kinds, or drill-stocks, which serve to carry any required number of drill-
points. The most simple of the drill-
stocks is shown in Fig. 541; it has
a
541.
the centre and pulley of the ordinary
drill, but the opposite end is pierced
with a nearly cylindrical hole, just at
the inner extremity of which a dia-
542.
metrical notch is filed. The drill is
shown separately at a; its shank is
made cylindrical, or exactly to fit the
hole, and a short portion is nicked
down also to the diametrical line, so
as to slide into the gap in the drill-stock, by which the drill is prevented from revolving; the end serves
also as an abutment whereby it may be thrust out with a lever. Sometimes a diametrical transverse
mortise, narrower than the hole, is made through the drill-stock, and the drill is nicked in on both sides;
the cylindrical hole of 541, should be continued to the bottom of the notch, the end of the drill should
be filed off obliquely, and it should be prevented from rotating, by a pin inserted through the cylindri-
cal hole parallel with the notch; the taper end of the drill would then wedge fast beneath the pin.
Drills are also frequently used in the drilling-lathe; this is a miniature lathe-head, the frame of
which is fixed in the table-vice; the mandrel is pierced for the drilla, and has a pulley for the bow,
therein resembling Fig. 542, except that it is used as a fixture.
The Fig. 542 just referred to, represents one variety of another common form of the drill-stock, in
which the revolving spindle is fitted in a handle, so that it may be held in any position, without the
necessity for the breastplate; the handle is hollowed out to serve for containing the drills, and is fluted
to assist the grasp.
Fig. 543 represents the socket of
a universal drill-stock," invented
by Sir John Robinson it is pierced
with a hole as large as the largest
543.
of the wires of which the drills are
formed, and the hole terminates in
an acute hollow cone. The end of
the drill-stock is tapped with two
holes, placed on a diameter; the
one screw, a, is of a very fine thread,
and has at the end two shallow
diametrica' notches; the other, b, is
of a coarser thread and quite flat at
the extremity. The wire-drill is
placed against the bottom of the
hole, and allowed to lean against the adjusting-screw a, and if the drill be not central, this screw is
moved one or several quarter-turns, until it is adjusted for centrality; after which the tool is strongly
fixed by the plain set-screw b.
Fig. 544 is a drill-stock, contrived by Mr. William Allen: it consists of a tube, the one end of which
has a fixed centre and pulley much the same as usual; the opposite end of the tube has a piece of steel
fixed into it, which is first drilled with a central hole, and then turned as a conical screw, to which is
fitted a corresponding screw-nut n; the socket is then sawn down with two diametrical notches, to
make four internal angles, and lastly, the socket is hardened. When the four sections are compressed
by the nut, their edges stick into the drill and retain it fast, and provided the instrument is itself con-
centric, and the four parts are of equal strength, the centrality of the drill is at once ensured. The out-
side of the nut, and the square hole in the key k, are each taper, for more ready application; and the
drills are of the most simple kind, namely, lengths of wire pointed at each end, as in Fig. 545.
The sketch, Fig. 544, is also intended to explain another useful application of this drill-stock, as an up-
right or pump drill, a tool little employed in this country, (except in drilling the rivet-holes for mending
china and glass, with diamond drill,) but as well known among the oriental nations as the breast-drill.
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Holes that are too large to be drilled solely by the breast-drill and drill-bow, are frequently com-
menced with those useful instruments, and are then enlarged by means of the hand-brace, which is very
similar to that used in carpentry, except that it is more commonly made of iron instead of wood, is
somewhat larger, and generally made without the spring-catch.
Holes may be extended to about half an inch diameter, with the hand-brace; but it is much more
expeditious to employ still larger and stronger braces, and to press them into the work in various ways
by weights, levers, and screws, instead of by the muscular effort alone.
Fig. 546 represents the old smith's press-drill, which although cumbrous, and much less used than
formerly, is nevertheless simple and effective. It consists of two pairs of wooden standards, between
which works the beam a b; the pin near a is placed at any height, but the weight to is not usually
changed, as the greater or less pressure for large and small drills, is obtained by placing the brace more
or less near to the fulcrum a; and this part of the beam is shod with an iron plate, full of small centre-
holes for the brace. The weight is raised by the second lever cd, the two being united by a chain, and
a light chain or rope is also suspended from d, to be within reach of the one or two men engaged in
moving the brace. It is necessary to relieve the weight when the drill is nearly through the hole,
otherwise it might suddenly break through, and the drill becoming fixed, might be twisted off in the
neck.
546.
d
547.
a
0
R
0
8
The inconveniences in this machine are, that the upper point of the brace moves in an arc instead of
a right line the limited path when strong pressures are used, which makes it necessary to shift the
fulcrum a; and also the necessity for readjusting the work under the drill for each different hole,
which in awkwardly-shaped pieces is often troublesome.
A portable contrivance of similar date, is an iron bow-frame or clamp, shown in Fig. 547 the pressure
is applied by a screw, but in almost all cases, whilst the one individual drills the hole, the assistance of
another is required to hold the frame; Fig. 547 only applies to comparatively thin parallel works, and does
not present the necessary choice of position. Another tool of this kind, used for boring the side-holes
in cast-iron pipes for water and gas, is doubtless familiarly known; the cramp or frame divides into
two branches about two feet apart, and these terminate like hooks, which loosely embrace the pipe, 80
that the tool retains its position without constraint, and it may be used with great facility by one
individual.
Fig 548 will serve to show the general character of various con-
548.
structions of more modern apparatus, to be used for supplying the
pressure in drilling holes with hand-braces. It consists of a cylin-
drical bar a, upon which the horizontal rectangular rod b is fitted
z
0
with a socket, so that it may be fixed at any height, or in any
angular position, by the set-screw c. Upon b slides a socket, which
d
is fixed at all distances from a, by its set-screw d; and lastly, this
socket has a long vertical screw e, by which the brace is thrust into
the work.
d
The object to be drilled having been placed level, either upon the
ground, on trestles, on the work-bench, or in the vice, according to
circumstances, the screws c and d are loosened, and the brace is put
in position for work. The perpendicularity of the brace is then
examined with a plumb-line, applied in two positions, (the eye
being first directed as it were along the north and south line, and
then along the east and west,) after which the whole is made fast
by the screws c and d. The one hole having been drilled, the
socket and screws present great facility in readjusting the instru-
ment for subsequent holes, without the necessity for shifting the
work, which would generally be attended with more trouble than
altering the drill-frame by its screws.
Sometimes the rod a is rectangular, and extends from the floor
to the ceiling; it then traverses in fixed sockets, the lower of which
has a set-screw for retaining any required position. In the tool
represented, the rod a terminates in a cast-iron base, by which it
may be grasped in the tail-vice, or when required it may be fixed
upon the bench. In this case the nut on a is unscrewed; the cast-iron plate, when reversed and placed
on the bench, serves as a pedestal; the stem is passed through a hole in the bench, and the nut and
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BORING TOOLS.
washer, when screwed on the stem beneath, secure all very strongly together. Even in establishments
where the most complete drilling machines driven by power are at hand, modifications of the press-drill
are among the indispensable tools: many are contrived with screws and clamps, by which they are
attached directly to such works as are sufficiently large and massive to serve as a foundation.
Various useful drilling tools for engineering works, are fitted with left-hand screws, the unwinding
of which elongate the tools; so that for these instruments which supply their own pressure, it is only
necessary to find a solid support for the centre. They apply very readily in drilling holes within boxes
and panels, and the abutment is often similarly provided by projecting parts of the castings; or other-
wise the fixed support is derived from the wall or ceiling, by aid of props arranged in the most conve.
nient manner that presents itself.
Fig. 549 is the common brace, which only differs from that in Fig. 548 in the left-hand screw ; a right-
hand screw would be unwound in the act of drilling a hole when the brace is moved round in the usual
direction, which agrees with the path of a left-hand screw. The cutting motion produces no change in
the length of the instrument, and the screw being held at rest for a moment during the revolutic n, sets
in the cut but towards the last, the feed is discontinued, as the elasticity of the brace and work suffice
for the reduced pressure required when the drill is nearly through, and sometimes the screw is unwound
still more to reduce it.
549.
550.
551.
553.
The lever-drill, Fig. 550, differs from the latter figure in many respects; it is much stronger, and ap-
plicable to larger holes; the drill-socket is sufficiently long to be cut into the left-hand screw, and the
piece serving as the screwed nut, is a loop terminating in the centre point. The increased length of the
lever gives much greater purchase than in the crank-form brace, and in addition the lever-brace may
be applied close against a surface where the crank-brace cannot be turned round; in this case the lever
is only moved a half circle at a time, and is then slid through for a new purchase, or sometimes a span-
ner or wrench is applied directly upon the square drill-socket.
The same end is more conveniently fulfilled by the ratchet-drill, Fig. 551, apparently derived from
the last; it is made by cutting ratchet-teeth in the drill-shaft, or putting on the ratchet as a separate
piece, and fixing a pall or detent to the handle; the latter may then be moved backward to gather up
the teeth, and forward to thrust round the tool, with less delay than the lever in Fig. 550, and with the
same power, the two being of equal
length. This tool is also peculiarly
applicable to reaching into angles and
places in which neither the crank-
form brace nor the lever-drill will
554.
apply. Fig. 552, the ratchet-lever, in
part resembles the ratchet-drill, but
the pressure screw of the latter in-
strument must be sought in some of
the other contrivances referred to, as
the ratchet-lever has simply a square
WAS
aperture to fit on the tang of the
drill d, which latter must be pressed
forward by some independent means.
Fig. 553, which is a simple but
555.
necessary addition to the braces and
drill tools, is a socket having at the
one end a square hole to receive the
drills, and at the opposite, a square
tang to fit the brace; by this con-
trivance the length of the drill can be
temporarily extended for reaching deeply-seated holes. The sockets are made of various lengths, and
sometimes two or three are used together, to extend the length of the brace to suit the position of the
prop; but it must be remembered, that with the additional length the tortion becomes much increased,
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and the resistance to end-long pressure much diminished, therefore the sockets should have a bulk
proportionate to their length.
The French brace, Fig. 521, is also constructed in iron, with a pair of equal bevel-pinions, and a left-
hand centre-screw like the tools, Figs. 549, 550, and 551 ; it is then called the corner-drill. Sometimes,
also, as in the succeeding Figs. 554 and 555, the bevel-wheels are made with a hollow square or axis,
as in the ratchet-lever, Fig. 552 the driver then hangs loosely on the square shank of the drill-tool, or
cutter-bar, and when the pinion on the handle is only one-third or fourth of the size of the bevel-wheel
with the square hole, it is an effective driver for various uses; the long tail or lever serves to prevent
the rotation of the driver, by resting against some part of the work or of the work-bench.
All the before-mentioned tools are commonly found in a variety of shapes in the hands of the engineer,
but it will be observed they are all driven by hand-power, and are carried to the work. I shall conclude
this section with the description of a more recent drill-tool of the same kind.
This instrument is represented of one-eighth size, in the side view, Fig. 556, in the front view, 557,
and in the section, 558; it is about twice as powerful as Fig. 555, and has the advantage of feeding the
556.
557
558.
8
B
cut by a difforential motion. The tangent-screw moves at the same time the two worm-wheels a and b;
the former has fifteen teeth, and serves to revolve the drill; the latter has 16 teeth, and by the
difference between the two, or the odd tooth, advances the drill slowly and continually, which may be
thus explained.
The lower wheel a, of 15 teeth, is fixed on the drill-shaft, and this is tapped to receive the centre-
screw c, of four threads per inch. The upper wheel of 16 teeth is at the end of a socket d, (which is
represented black in the section Fig. 558,) and is connected with the centre-screw c, by a collar and
internal key, which last fits a longitudinal groove cut up the side of the screw c; now therefore the
internal and external screws travel constantly round, and nearly at the same rate, the difference of one
tooth in the wheels serving continually and slowly to project the screw c, for feeding the cut. To
shorten or lengthen the instrument rapidly, the side-screw e is loosened; this sets the collar and key
free from the 16 wheel, and the centre-screw may for the time be moved independently by a spanner.
The differential screw-drill, having a double thread in the large worm, shown detached at f, requires
if turns of the handle to move the drill once round, and the feed is one 64th of an inch for each turn of
the drill; that being the sum of 16 by 4.
Drilling and Boring Machines.-The motion of the lathe-mandrel is particularly proper for giving
action to the various single-cutting drills referred to; they are then fixed in square or round hole drill-
chucks which screw upon the lathe-mandrel. The motion of the lathe is more uniform than that of the
hand- nols, and the popit-head, with its flat boring-flange and pressure-screw, form a most convenient
arrangement, as the works are then carried to the drill exactly at right angles to the face. But in
drilling very small holes in the lathe, there is some risk of unconsciously employing a greater pressure
with the screw, than the slender drills will bear. Sometimes the cylinder is pressed forward by a
horizontal lever fixed on a fulcrum; at other times the cylinder is pressed forward by a spring, by a
rack and pinion motion, or by a simple lever, and the best arrangement of this latter kind is that next
to be described.
In the manufacture of harps there is a vast quantity of small drilling, and the pressure of the cylinder
popit-head is given by means of a long, straight, double-ended lever, which moves horizontally, (at
about one-third from the back extremity,) upon a fixed post or fulcrum erected upon the backboard of
the lathe. The front of the lever is connected with the sliding cylinder by a link or connecting rod, and
the back of the lever is pulled towards the right extremity of the lathe, by a cord which passes over a
pulley at the edge of the backboard, and then supports a weight of about twenty pounds.
Both the weight and the connecting-rod may be attached at various distances from the fixed fulcrunn
between them. When they are fixed at equal distances from the axis of the lever, the weight, if
twenty pounds, presses forward the drill with twenty pounds, less a little friction; if the weight be two
inches from the fulcrum and the connecting-rod eight inches, the effect of the weight is reduced to five
pounds; if, on the other hand, the weight be at eight and the connecting-rod at two inches, the pressure
is fourfold, or eighty pounds.
The connecting-rod is full of holes, 80 that the lever may be adjusted exactly to reach the body of
the workman, who, standing with his face to the mandrel, moves the lever with his back, and has
therefore both hands at liberty for managing the work. Sometimes a stop is fixed on the cylinder, for
drilling holes to one fixed depth; gages are attached to the flange for drilling numbers of similar pieces
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BORING TOOLS.
at any fixed distance from the edge: in fact, this very useful apparatus admits of many little additions
to facilitate the use of drills and revolving cutters.
Great numbers of circular objects, such as wheels and pulleys, are chucked to revolve truly upon the
lathe-mandrel, whilst a stationary drill is thrust forward against them, by which means the concentricity
between the hole and the edge is ensured.
The drills employed for boring works chucked on the lathe, have mostly long shafts, some parts of
which are rectangular or parallel, so that they may be prevented from revolving by a hook-wrench, a
spanner, or a hand-vice, applied as a radius, or by other means. The ends of the drill-shafts are pierced
with small centre-holes, in order that they may be thrust forward by the screw of the popit-head, either
by hand or by self-acting motion; namely, a connection between either the mandrel or the prime mover
of the lathe, and the screw of the popit-head, by cords and pulleys, by wheels and pinions, or other
contrivances.
The drills, Figs. 528 and 530, are used for boring ordinary holes; but for those requiring greater
accuracy, or a more exact repetition of the same diameter, the lathe-drills, Figs. 559 to 562, are
commonly selected. Fig. 559, which is drawn in three views and to the same scale as the former
examples, is called the half-round bit, or the cylinder-bit. The extremity is ground a little inclined to
the right angle, both horizontally and vertically, to about the extent of three to five degrees. It is
necessary to turn out a shallow recess exactly to the diameter of the end of the bit as a commencement,
the circular part of the bit fills the hole, and is thereby retained central, whilst the left angle removes
the shaving. This tool should never be sharpened on its diametrical face, or it would soon cease to
deserve its appellation of half-round bit: some indeed give it about one-thirtieth more of the circum-
ference. It is generally made very slightly smaller behind, to lessen the friction; and the angle, not
intended to cut, is a little blunted half-way round the curve, that it may not scratch the hole from the
pressure of the cutting edge. It is lubricated with oil for the metals generally, but is used dry for hard
woods and ivory, and sometimes for brass.
559.
560.
561.
562.
563.
The rose-bit, Fig. 560, is also very much used for light finishing cuts, in brass, iron, and steel the
extremity is cylindrical, or in the smallest degree less behind, and the end is cut into teeth like a
countersink; the rose-bit, when it has plenty of oil, and but very little to remove, will be found to act
beautifully, but this tool is less fit for cast-iron than the bit next to be described. The rose-bit may be
used without oil for the hard woods and ivory, in which it makes a very clean hole; but as the end of
the tool is chamfered, it does not leave a flat-bottomed recess the same as the half-round bit, and is
therefore only used for thoroughfare holes.
The drill, Fig. 561, is much employed, but especially for cast-iron work; the end of the blade is made
very nearly parallel; the two front corners are ground slightly rounding, and are chamfered; the
chamfer is continued at a reduced angle along the two sides, to the extent of about two diameters in
length; this portion is not strictly parallel, but is very slightly largest in the middle, or barrel-shaped:
this drill is used dry for cast-iron.
Fig. 561, in common with all drills that cut on the side, may, by improper direction, cut sidewise,
making the hole above the intended diameter; but when the hole has been roughly bored with a
common fluted drill, the end of the latter is used as a turning tool, to make an accurate chamfer; the bit
561 is then placed through the stay as shown in Fig. 562, and is lightly supported between the chamfer
upon the work and the centre of the popit-head: the moment any pressure comes on the drill, its
opposite edges stick into the inner sides of the loop, which thus restrains its position; much the same as
the point and edges of the turning tools for iron dig into the rest, and secure the position of those tools.
It is requisite the drill and the loop should be exactly central. Fig. 562 shows the common form of
the stay when fitted to the lathe-rest, but it is sometimes made as a swing-gate, to turn aside, whilst
the piece which has been drilled is removed, and the next piece to be operated upon is fixed in the
lathe. Sometimes also the drill 561, has blocks of hard wood attached above and below it, to com-
plete the circle; this is usual for wrought-iron and steel, and oil is then employed.
These three varieties are exclusively lathe-drills, and are intended for the exact repetition of a number
of holes of the particular sizes of the bits, and which, on that account, should remove only a thin shaving
to save the tools from wear.
The cylinder bits, however, may be used for enlarging holes below half an inch, to the extent of about
one-third their diameter at one cut; and for holes from half an inch to one inch, about one-fourth their
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BORING TOOLS.
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diameter or less; and as the bits increase in size, the proportion of the cut to the diameter should
decrease.
The cylinder bit is not intended to be used for drilling holes in the solid material, and as the piercing
drills are apt to swerve in drilling small and very deep holes, the following rotation in the tools is
sometimes resorted to. A drill, Fig. 531, say three-sixteenths diameter, is first sent in to the depth of
an inch or upwards, and the h de is enlarged by a cylinder bit of one-quarter inch diameter. The centre
at the end of the hole is then restored to exact truth, by Fig. 532, a recentering drill, the plug of which
exactly fits the hole made by the cylinder bit; the extremity of the recentering drill then acts as n
fixed turning-tool; and should the first drill have run out of its position, 532 corrects the centre at the
end of the hole. Another short portion is then drilled with 528. enlarged with the half-round bit, and
the conical extremity is again corrected with the recentering drill; the three tools are thus used in ro-
tation until the hole is completed, and which may be then cleaned out with one continued cut, made
with a half-round bit a little larger than that previously used.
Some of the large half-round bits are 80 made, that the one stock will serve for several cutters of
different diameters. In the bit used for boring out ordnance, the parallel shaft of the boring-bar
slides accurately in a groove, exactly parallel with the bore of the gun; the cutting blade is a small
piece of steel affixed to the end of the half-round block, which is either entirely of iron, or partly of
wood; and the cut is advanced by a rack and pinion movement, actuated either by the descent of a
constant weight, or by a self-acting motion derived from the prime mover. For making the spherical,
parabolical, or other termination to the bore, cutters of corresponding forms are fixed to the bar.*
There are very many works which, from their weight or size, cannot be drilled in the lathe in its or-
dinary position, as it is scarcely possible to support them steadily against the drill; but these works
are readily pierced in the drilling-machine, which may be viewed as a lathe with a vertical mandrel,
and with the flange of the popit-head enlarged into a table for the work, which then lies in the hori-
zontal position simply by gravity, or is occasionally fixed on the table by screws and clamps. The
structure of these important machines admits of almost endless diversity, and in nearly every manufac-
tory some peculiarity of construction may be observed.
Figs. 564 and 565 exhibit Nasmyth's Portable Hand-drill, which is introduced as a simple and effi-
cient example, that may serve to convey the general characters of the drilling-machines. The spindle
564.
565.
is driven by a pair of bevel-pinions; the one is attached to the axis of the vertical fly-wheel, the other
to the drill-shaft, which is depressed by a screw moved by a small hand-wheel.
Sometimes, as in the lathe, the drilling-spindle revolves without endlong motion, and the table is
raised by a treadle or by a hand-lever; but more generally the drill-shaft is cylindrical and revolves in,
and also slides through, fixed cylindrical bearings. The drill-spindle is then depressed in a variety of
ways; sometimes by a simple lever, at other times, by a treadle which either lowers the shaft only one
single sweep, or by a ratchet that biings it down by several small successive steps, through a greater
distance; and mostly a counterpoise weight restores the parts to their first position when the hand or
foot is removed. Friction-clutches, trains of differential wheels, and other modes, are also used in de-
pressing the drill-spindle, or in elevating the table by self-acting motion. Frequently also the platform
admits of an adjustment independent of that of the spindle, for the sake of admitting larger pieces;
the horizontal position of the platform is then retained by a slide, to which a rack and pinion move-
ment, or an elevating screw, is added.
Drilling-machines of these kinds are generally used with the ordinary piercing-drills, and occasion-
ally with pin-drills; the latter instrument appears to be the type of another class of boring tools,
namely, cutter-bars, which are used for works requiring holes of greater dimensions, or of superior acc'i-
racy, than can be attained by the ordinary pointed drills.
The small application of this principle, or of cutter-bars, is shown on the same scale as the former
drills, in Fig. 566; the cutter c, is placed in a diametrical mortise in a cylindrical boring-bar, and is fixed
by a wedge; the cutter c extends equally on both sides, as the two projections or ears embrace the
sides of the bar, which is slightly flattened near the mortises.
Cutter-bars of the same kind, are occasionally employed with cutters of a variety of forms, for
The outside of the gun is usually turned, whilst the boring is going on, by the hand-tools. A plug of copper is
acrewed into the brass guns to be perforated for the touch-hole, copper being less injured by repeated discharges than
the alloy of 9 parts copper and 1 part tin, used for the general substance of the gun; the curved bit smooths off the end of
the plug.
23
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BORING TOOLS.
making grooves, recesses, mouldings, and even screws, upon parts of heavy works, and those which can-
not be conveniently fixed in the ordinary lathe. Fig. 567 represents one of these.
c
566.
568.
567.
The larger application of this principle is shown in Fig. 568, in which a cast-iron cutter-block IS keyed
fast upon a cylindrical bar; the block has four, six, or more grooves in its periphery. Sometimes the
work is done with only one cutter, and should the bar vibrate, the remainder of the grooves are filled
with pieces of hard wood, so as to complete the bearing at 80 many points of the circle occasionally
cutters are placed in all the grooves, and carefully adjusted to act in succession-that is, the first stands
a little nearer to the axis than the second, and so on throughout, in order that each may do its share of
the work but the last of the series takes only a light finishing cut, that its keen edge may be the longer
preserved. In all these cutters the one face is radial, the other differs only four or five degrees from the
right angle, and the corners of the tools are slightly rounded.
These cutter-bars, like the rest of the drilling and boring machinery, are employed in a great variety
of ways, but which resolve themselves into three principal modes:
First. The cutter-bar revolves without endlong motion, in fixed centres or bearings-in fact, as a spindle
in the lathe; the work is traversed. or made to pass the revolving cutter in a right line, for which end
the work is often fixed to a traversing slide-rest. This mode requires the bar to measure, between the
supports, twice the length of the work to be bored, and the cutter to be in the middle of the bar it is
therefore unfit for long objects.
Secondly. The cutter-bar revolves, and also slides with endlong motion, the work being at rest; the
bearings of the bar are then frequently attached in some temporary manner to the work to be bored,
and are often of wood.*
In another common arrangement, the boring-bar is mounted in headstocks, much the same as a trav-
ersing mandrel, the work is fixed to the bearers carrying the headstocks, and the cutter-bar is advanced
by a screw. The screw is then moved either by the hand of the workman, by a star-wheel, or a ratch-
et-wheel, one tooth only in each revolution, or else by a system of differential wheels, in which the ex-
ternal screw has a wheel, say of 50 teeth, the internal screw a wheel of 51 teeth, and a pair of equal
wheels or pinions drives these two screws continually, so that the advance of the one-fiftieth of a turn
of the screw, or their difference, is equally divided over each revolution of the cutter-bar, much the
same as in the differential motion of the screw-drill, Fig. 556.
This second method only requires the interval between the fixed bearings of the cutter-bar to be as
much longer than the work, as the length of the cutter-block; but the bar itself must have more than
twice the length of the work, and requires to slide through the supports.
Cutter-bars of this kind are likewise used in the lathe; in the act of boring, the end of the bar then
slides like a piston into the mandrel. Such bars are commonly applied to the vertical boring-machines
of the larger kinds, which are usually fitted with a differential apparatus, for determining the progress
of the cut; the bar then slides through a collar fixed in the bed of the machine.
In some of the large boring-machines either one or two horizontal slides are added, and by their aid,
series of holes may be bored in any required arrangement. For instance, the several holes in the beams,
or side-lerers, and cranks of steam-engines are bored exactly perpendicular, in a line, and at any precise
distances, by shifting the work beneath the revolving spindle upon the guide or railway; in pieces of
other kinds, the work is moved laterally during the revolution of the cutters, for the formation of elon-
gated countersinks and grooves.
Thirdly. In the largest applications of this principle, the boring-bar revolves upon fixed bearings
without traversing and it is only needful that the boring-bar should exceed the length of the work, by
the thickness of the cutter-block, of which it has commonly several of different diameters. The cutter-
block, now sometimes ten feet diameter, traverses as a slide down a huge boring-bar, whose diameter
is about thirty inches. There is a groove and key to couple them together, and the traverse of the
cutter-block down the bar is caused by a side screw, upon the end of which is a large wheel, that en-
gages in a small pinion, fixed to the stationary centre or pedestal of the machine. With every revolu-
tion of the cutter-bar, the great wheel is carried around the fixed pinion, and supposing these be as 10
to 1, the great wheel is moved one-tenth of a turn, and therefore moves the screw one-tenth of a turn
also, and slowly traverses the cutter-block.
The contrivance may be viewed as a huge, self-acting, and revolving sliding-rest; the cutter-bars are
equally applicable to portions of circles, such as the D-valves of steam-engines, as well as to the
enormous interior of the cylinder itself.
All the preceding boring tools cut almost exclusively upon the end alone. They are passed entirely
through the objects, and leave each part of their own particular diameter, and therefore cylindrical;
but I now proceed to describe other boring tools, that cut only on their sides, go but partly through the
. Cylinders of 40 inches diameter for steam-engines have been thus bored by attaching a cast-iron cross to each end of
the cylinder: the crosses are bored exactly to fit the boring-bar. one of them carries the driving-gear, and the bar is thrust
endlong by means of a screw, moved by a ratchet or star wheel.
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BORING TOOLS.
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work, and leave its section a counterpart of the instrument. These tools are generally conical, and
serve for the enlargement of holes to sizes intermediate between the gradations of the drills, and also
for the formation of conical holes, as for valves, stopcocks, and other works. The common pointed
drill, or its multiplication in the rose countersink, is the type of the series but in general the broaches
have sides which are much more nearly parallel.
Broaches for making taper holes.-The tools for making taper holes, are much less varied than the
drills and boring tools for cylindrical holes. Thus the carpenter employs only the rimer, which is a
fluted tool like the generality of his bits; it is sharpened from within, as shown in Fig. 569, so as to
act like a paring tool. Flutes and clarionets are first perforated with the nose-bit, and then broached
with taper holes, by means of tools of this kind, which are very carefully graduated as to their dimen-
sions. Fig. 570 represents a German rimer, used by wheelwrights for inlaying the boxes of axletrees;
the loose blade is separated from the shell of the instrument, by introducing slips of leather or wood
between the two; the detached cutter fits on a pin at the front, and is fixed by a ring or collar against
the shaft.
569.
571.
572.
573.
574.
575.
576.
577.
570.
578.
A curious rimer for the use of wine-coopers, by which the holes were made more truly circular, and
the shavings were prevented from dropping into the cask. The stock of the instrument consists of a
hollow brass cone, seen in section in Fig. 571; down one side there was a slit for containing a narrow
blade or cutter, fixed by three or four screws placed diametrically. The tube was thus converted into
a conical plane; the shavings entered within the tube, and were removed by taking out a cork from
the small end of the cone.
The broaches for metal are made solid, and of various sections; as half-round, like Fig. 572: the
edges are then rectangular. But more commonly the broaches are polygonal, as in Fig. 573, except that
they have 3, 4, 5, 6, and 8 sides, and their edges measure respectively 60, 90, 108, 120, and 135 degrees.
The four, five, and six-sided broaches are the most general, and the watchmakers employ a round
broach in which no angle exists, and the tool is therefore only a burnisher, which compresses the metal
and rounds the hole.
Ordinary broaches are very acute, and Fig. 574 may be considered to represent the general angle at
which their sides meet-namely, less than one or two degrees; the end is usually chamfered off with
as many facets as there are sides, to make a penetrating point, and the opposite extremity ends in a
square tang, or shank, by which the instrument is worked.
Square broaches, after having been filed up, are sometimes twisted whilst red-hot. Fig. 577 shows
one of these; the rectangular section is but little disturbed, although the faces become slightly concave.
The advantage of the tool appears to exist in its screw form: when it is turned in the direction of the
spiral, it cuts with avidity and requires but little pressure, as it is almost disposed to dig too forcibly
into the metal: when turned the reverse way, as in unscrewing, it requires as much or more pressure
than similar broaches not twisted. This instrument, if bent in the direction of its length, either in the
act of twisting or hardening, does not admit of correction by grinding, like those broaches having plane
faces It is not much used, and is almost restricted to wrought-iron and steel.
Large countersinks that do not terminate in a point, are sometimes made as solid cones; a groove is
then formed up one side, and deepest towards the base of the cone, for the insertion of a cutter, (see
Fig. 574.) As the blade is narrowed by sharpening, it is set a little forward in the direction of its
length, to cause its edge to continue slightly in advance of the general surface, like the iron of a plane
for cutting metal
Fig. 579 represents Mr. Richard Roberts' broach, in which four detached blades are introduced, for
the sake of retaining the cone or angle of the broach with greater facility. The bar or stock has four
579.
shallow longitudinal grooves, which are nearly radial on the cutting face, and slightly undercut on the
other The grooves are also rather deeper behind, and the blades are a little wedge-form both in sec-
tion and in length, to constitute the cone, and the cutting edges. In restoring the edges of the blades,
they are removed from the stock, and their angles are then more easily tested: when replaced, they are
set nearer to the point, to compensate for their loss of thickness.
Broaches are also used for perfecting cylindrical holes, as well as for making those which are taper.
The broaches are then made almost parallel, or a very little the highest in the middle; they are filed,
with two or three planes at angles of 90 degrees, as in Fig. 575 or 576. The circular part net being
able to cut, serves as a more certain base for foundation, than when the tool is a complete polygon; and
the stems are commonly made small enough to pass entirely through the holes, which then agree very
exactly as to size. Such tools are therefore rather entitled to the name of finishing drills, than broaches
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BRAN SEPARATOR.
The size of the parallel broaches is often slightly increased, by placing a piece or two of paper at
the convex part; leather and thin metal are also used for the same purpose. Gun-barrels are broached
with square broaches, the cutting parts of which are about eight to ten inches long they are packed
on the four sides with slips or spills of wood, to complete the circle, as in Fig. 577, in which the tool is
supposed to be at work. The size of the bit is progressively enlarged by introducing slips of thin
paper, piece by piece between two of the spills of wood and the broach; the paper throws the one
angle more towards the centre of the hole, and causes a corresponding advance in the opposite or the
cutting angle. Sometimes, however, only one spill of wood is employed.
A broach used by the philosophical instrument makers in finishing the barrels of air-pumps, consisted
of a thin plate of steel inserted diametrically between two blocks of wood, the whole constituting a
cylinder with a scraping edge slightly in advance of the wood; slips of paper were also added.
According to the size of the broaches, they are fixed in handles like brad-awls; they are used in the
brace, or the tap-wrench-námely, a double-ended lever with square central holes. Sometimes also
broaches are used in the lathe just like drills, and for large works, broaching machines are employed;
these are little more than driving-gear terminating in a simple kind of universal joint, to lead the power
of the steam-engine to the tool, which is generally left under the guidance of its own edges, according
to the common principle of the instrument.
In drills and broaches, the penetrating angles are commonly more obtuse than in turning tools; thus
in drills of limited dimensions, the hook-form of the turning tool for iron is inapplicable, and in the
larger examples, the permanence of the tool is of more consequence than the increased friction. But
on account of the additional friction excited by the nearly rectangular edges, it is commonly necessary
to employ a smaller velocity in boring than in turning corresponding diameters, in order to avoid soften-
ing the tool by the heat generated; and in the ductile fibrous metals, as wrought-iron, steel, copper,
and others, lubrication with oil, water, &c., becomes more necessary than in turning.
The drills and broaches form together a complete series. First the cylinder-bit, the pin-drills, and
others with blunt sides, produce cylindrical holes by means of cutters at right angles to the axis; then
the cutter becomes inclined at about 45 degrees, as in the common piercing-drill and cone countersink;
the angle becomes much less in the common taper broaches; and finally disappears in the parallel
broaches, by which we again produce the cylindrical hole, but with cutters parallel with the axis of
the hole.
Still considering the drills and broaches as one group. the drills have comparatively thin edges, always
less than 90 degrees, yet they require to be urged forward by a screw or otherwise, the resistance being
sustained in the line of their axes. The broaches have much more obtuse edges, never less than 90, and
sometimes extending to 135 degrees; and yet the greater force required to cause the penetration of their
obtuse edges into the material, is supplied without any screw, because the pressure in all these varied tools
is at right angles to the cutting edge.
Thus supposing the sides of the broach extended until they meet in a point, as in Fig. 578, we shall
find the length will very many times exceed the diameter, and by that number will the force employed
to thrust forward the tool be multiplied, the same as in the wedge, whether employed in splitting timber
or otherwise; and the broach being confined in a hole, it cannot make its escape, but acts with great
lateral pressure, directed radially from each cutting edge; and the broach under proper management
leaves the holes very smooth and of true figure.
BOW-STRING BRIDGE, OR TENSION BRIDGE, a kind of suspension bridge, the roadway
being suspended from wrought-iron rods; but, instead of the usual suspension chains, cast-iron segments
are thrown across the ravine, or river, as the case may be, which are rested on proper abutments upon
each side.
580.
Bridge at Howslett.
The span of the Monk Bridge is 112 feet; that erected at Howslett, has a span of 152 feet, and the
rise of the arch is 33 feet; the total height above the level of the water is 43 feet, the width of the
bridge is 33 feet.
BOX-WOOD. See WOODS, varieties of.
BRACKETS AND PILLOW-BLOCKS. See GEARING.
BRAKE, OR CONVOY, the drag applied generally to the wheels of carriages to check their velocity
in passing down hills, by means of friction. The brake attached to railway carriages consists of a piece
of wood, which is pressed upon the rim of the wheels of the carriages by a hand-lever, worked by the
brakeman. The brake of the tender alone affords a sufficient resistance to stop a train under ordinary
circumstances. The term is also used in reference to the contrivance for arresting the motion of
machinery.
BRAN SEPARATOR. This is the invention of E. R. Benton, of Milwaukie, Wisconsin, and it has
been deemed one of no minor importance. The following description of its construction and operation,
in connection with the accompanying engravings, will enable our readers fully to understand it.
Fig. 581 is a sectional view, and Fig. 582 a sectional plan, with the top parts removed in order more
plainly to show the parts represented in Fig. 581. A, is the shaft. B, the cylinder. C, the inner re-
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BRAN SEPARATOR.
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volving shell and D, the outer or stationary shell. The cylinder is made by framing staves of the
form, and in the position represented at 1, 2, 3, &c., Fig. 582, into corresponding cast heads. The staves
thus forming the longitudinal and working surface, and which may be covered with any kind of material
that will make it rough and durable. Air is let into the cylinder, the best at the lower end, through
equidistant holes around the centre, and the quantity gaged by a circular revolving slide, and spaces
between the staves emit it to carry the flour and other stuffs through the several qualities of wire-cloth
with which the inner surface of the revolving shell is covered. The cylinder is driven by a belt and
581.
il
e
583.
Y
6
M
0
a
a
e
D
D
Q
E
B
A
G
K
L
M
P
2
582.
S
U
R
T
F
DL
H
pulleys, as is represented at the bottom of Fig. 581 ; and the bridge and oilpot for the point and step,
and the fixture for supporting the upper journal-box of the shaft, are cast in a piece with their respec-
tive heads of the outer shell, thus rendering this part of the machine perfect. The inner surface of the
revolving shell is covered with the above-named wire-cloth. Thus, the space between the top and the
bevelled dividing ring E, Fig. 581, is covered with a quality that will let through little else but pure
flour, which falls, and by the dividing ring is conducted into an endless trough I, attached to the
inner and sheet-iron or zinc-lined surface of the stationary shell, and by the sweepers F, attached
to the revolving shell, is brought around and discharged at the spout G. The space between the divi-
ding rings E and H is covered with a quality that will discharge an inferior quality to the above, which
falls, as above into the endless trough J, and by the sweepers K, is brought around and discharged at
the spout L The space between the dividing rings H and M is covered with a quality that will take
out the fine particles of the bran, called dusting, which falls, as above, into the endless trough N, and by
the sweepers O, is discharged at the spout P. The space between the dividing ring M and the bottom,
is covered with a quality that will separate the shorts from the bran, the shorts falling to the bottom,
or into the endless trough R, and by the sweepers S is discharged at the spout T, the bran passing down
inside of the revolving shell, and by the arms U, of its cast head, is swept around to, and discharged
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182
BREAKWATER.
at the spout V. The revolving shell is driven by a combination of gear-wheels, thus: The pinion
above, on the principal shaft A, Fig. 581, drives the wheel X, on the small or centre shaft Y, and the
pinion Z, on the last-named shaft, drives the projecting cogged-wheel rim a, cast in a piece with the top
head, which will turn it the same way with the cylinder; and to turn it the contrary way, the project-
ing rim a must be so large as to circumscribe and be driven by the pinion Z, working into cogs upon its
inner periphery, as seen by the figures W, of pitch circles, the figures denoting the corresponding pitch
circles of the wheels and pinions in Fig. 581. b, is a circular inclined plane, so calculated as to
lift a mallet or hammer to strike upon the end of the revolving shell to keep the cloth from clog-
ging, the blow to be struck upon a block resting upon its upper rim, and projecting up through a cor-
responding hole in the stationary head, as at C. d, is a set of cams on the shaft Y, which shake a
wire sieve e, that receives the uncleaned and unseparated bran, shorts, and dustings from the bolts, as
through the spout f, the sieve carrying off all coarse extraneous stuff that might injure the machine,
the bran falling through the sieve and entering the machine passing between the arms of the upper
head of the revolving shell on to the head of the cylinder.
BRASS, (see SOLDERING :) Yellow; tough for engine work; for heavy bearings. See DETAILS OF
ENGINES.
BRASS-TURNING TOOLS. See TURNING TOOLS.
BRAZING COPPER. See SOLDERING.
BRAZING SOLDERS. See DETAILS OF ENGINES.
BRAZILETTO. See WOODS, varieties of.
BRAZIL-WOOD. See WOODS, varieties of.
BREAKWATER. A kind of artificial embankment, dike, or rampart, formed of large stones, and
erected for the purpose of protecting the entrances of harbors, also roadsteads, from the effects of
violent winds, by breaking the force of the waves of the sea; the shipping, moored behind them, lying
perfectly secure.
The most celebrated works of this description are those of Cherbourg, in France, and Plymouth, in
England.
That of Cherbourg was the first executed, having been begun in the year 1783: the building of the
wall was commenced upon upright cones of timber, and each cone was intended to have been about
150 feet diameter at the base, 60 feet at the top, and about 60 or 70 feet high, the depth of water at
spring-tides, in the line in which they were sunk, varying from 56 to 70 feet; they were also intended
to have been filled with stones to the top, and after allowing some time for settling, the masonry was
intended to have been commenced upon them but a few of these cones only were constructed, when,
in consequence of the difficulty of the undertaking, the whole was covered with large stones, thrown in
at random. This breakwater is 10 feet above the highest tides, and has a roadway or platform 20 feet
wide on the side next the shore, a parapet-wall being built upon it on that next the sea.
The Plymouth breakwater was commenced in 1812. It is composed of blocks of stone, 1} to 2 and
3 tons weight, and consists of a central part, 1000 yards long; and two wings, each 350 yards long,
584.
Plan of Plymouth Breakwater.
directed towards the sea, and forming angles of 158° with the centre portion. A transverse section
taken through the breakwater shows an average base of 290 feet, and the breadth at the top is 48 feet,
with an average depth of water, at low spring-tides, of 36 feet; the side next the sea is sloped in the
585.
A
D
B
B
Section of Plymouth Breakwater.-A A, high-water spring tides. B B, low-water spring tides. D, the fore-shore.
proportion of 1 perpendicular to 7 horizontal, and the side next the land is 1 to 5; these sides were
not intended, originally, to have had so great a slope, but, in consequence of the violence of the waves
during its construction, it was thought proper to increase them, as executed.
The stone was raised in large blocks, some of which contained 10 tons, and were thrown into the
sea, in the direction set out for the breakwater, care being taken that the greater nunber were de-
posited upon the outer slope. After a number of these large masses had been lowered, A smaller
class of stones, quarry rubbish, rubble, and lime-screenings, were thrown in to fill up the interstices,
and close all the cavities; these found their position, by the action of the sea, and the great mass be-
came, as it advanced, perfectly wedged together.
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BRICK-MAKING.
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BREAKWATER GLACIS, (sometimes termed stone-pave-
ment.) The stone pavings next the sea, in pier erections they
586.
are mostly laid upon a slope, or curved, the stones being of
sufficient weight to resist the action of the sea.
BREASTS. The name given to the bushes connected with
small shafts or spindles.
BREAST-WALL A wall built up breast-high, as a para-
pet-wall, or a retaining-wall, placed at the foot only of a slope.
BRICK. An artificial preparation of clay, sand, and ashes,
Section showing the Breakwater Glacis.
burnt in a kiln, or clamp, and used for building, and for other
purposes good brick-earth is also sometimes found in a natural state. A good brick is about 84 inches
long, 41 inches wide, and 21 inches thick, when burnt.
BRICK-MACHINE Among the machines which have been produced by the inventors of our sister
city of Philadelphia is that of Stephen Ustick's, for Moulding and Pressing Bricks from untempered
clay, a representation of which is given below. It will readily be seen that it is simple in its construc-
tion, as all the motions to the pistons and fillers are given by stationary cams as the wheel of the
moulds rotates. The pressing cams give a powerful progressive pressure-the same in effect as that
given by toggle-joint levers.
587.
M
H
B
A A, frames, between which the cams
G, the pinion on the driving-shaft.
ing the brick with it, by a projection
BC and the centre shaft D are firmly
G, revolving wheel on the shaft D, hav-
of the cam-wheel E.
bolted.
ing pairs of parallel arms to which
N, a perpendicular cam which operates
BC, cams which give the pressure to
the moulds are bolted, and between
the plunger 0, to discharge the bricks
the outer pistons.
which the pistons slide.
from the pistons.
D, centre shaft on which the wheel of
H, the moulds.
P P, cams which bring the pistons into
moulds revolves.
11, pistons which condense the clay.
the moulds.
E, cam-wheel on the centre shaft D,
K, the fillers which supply the moulds
Q, annular receiver, into which the clay
which gives the pressure to the inner
with clay.
falls from the pulverizer.
pistons.
L, the hoppers above the fillers.
R, openings in the bottom of the re-
F, cam-wheel on side shaft, above the
M, a light cam, which brings the outer
ceiver communicating with the hop-
cam-wheel E. which gives motion to
piston out of the mould after the
pers L.
the fillers. The view of this cam-
brick is pressed, while the inner one
S, scraper which fills the hoppers.
wheel is obstructed by the receiver.
is thrust through the mould, carry-
After the first pressure is given to the clay, which commences when the outer piston is at the front
end of the cam B, the air is let off of the brick by the filler, (the front end of which is a false top to the
mould,) moving inwards, leaving the upper part of the brick bare for the condensed air to escape it
then moves back to its place before the piston reaches the back end of the cam C, and then the second
pressure is given to the brick, without any loss of time, as a brick is made in each mould in every
revolution of the wheel.
BRICK-MAKING. Brick is a kind of factitious stone, made of a fatty earth formed into a parallelopiped,
about 4 inches broad by 8 or 9 inches in length, by a wooden mould, and then baked or burnt either in
a kiln or a clamp, to serve the purposes of building. Bricks appear to have been used for architectural
purposes at a very remote period, as we learn from the Scriptures that the Israelites were employed to
make bricks in Egypt; and some of the most durable of the Greek and Roman monuments which have
come down to us, are wholly, or in great part, constructed of this material. In the East they bake their
bricks in the sun; the Romans used them crude, only leaving them a long time in the air to dry, about
four or five years. In modern times, brick-making is nowhere carried to greater perfection than in
Holland, where most of the floors of the houses, and frequently the streets. are paved with excellent
and very durable bricks. Loam and marl are in England considered the best materials for bricks. The
former is a natura! mixture of sand and clay, which may be converted at once into bricks; marl is a
mixture of limestone and clay in various proportions. The neighborhood of London is remarkably
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BRICK-MAKING.
adapted for the making of bricks, the soil of the whole surrounding country being clay at a certain
depth, generally below a bed of gravel, and the bottom of the Thames yielding the sand which is used
in this manufacture; but great practical carelessness seems to pervade the whole business as conducted
there. The following is a description of the process as it is usually conducted around the me-
tropolis: The earth is dug up in the autumn, and suffered to remain in a heap until the next
spring, that it may be well penetrated by the air, and particularly by the winter frosts, which, by
pulverizing the more tenacious particles, greatly assists the operations of mixing and tempering. In
making up this heap for the season, the soil and ashes, or sand, are laid in alternate layers or strata,
each stratum containing such a thickness as the stiffness of the soil may admit or require. In temper-
ing the earth, much judgment is required as to the quantity of sand to be thrown into the mass, for too
much renders the bricks heavy and brittle, and too little leaves them liable to shrink and crack in the
burning. The addition of sea-coal ashes, as practised about London, not only makes it work easy, but
saves fuel, as when the mixture is afterwards sufficiently heated these bricks are chiefly burned by the
fuel contained in the clay. When the brick making season arrives, the heap is dug up, the stony parti-
cles carefully removed, and the mass properly tempered by a thorough incorporation and intermixture
of the materials, with the addition of as little water as possible, 80 as to form a tough viscous paste.
If, in this operation, too much water be used, the paste will become almost as dry and brittle as the soil
of which it is composed. In order more effectually and regularly to mix the loam and ashes, it is now
generally performed in A sort of mill, named a pug-mill This consists of a large tub or tun, fixed
perpendicularly in the ground, and having an upright bar, fitted with knives, placed obliquely. The
upright bar is turned by a horizontal lever, to which a horse is attached, and the soil being put in at
top, is, by the revolution of the knives, forced through a hole in the side of the tub near the bottom,
whence it is removed to the mould-table, which is placed under a moveable shed, and is strewed with
dry sand. A girl rolls out a lump somewhat larger than the mould will contain. The moulder receives
this lump from the girl, throws it into his mould previously dipped in dry sand, and with a flat smooth
stick about 8 inches long, kept for the purpose in a pan of water, he strikes off the overplus of the soil;
he then turns the brick out of the mould upon a thin board rather larger than the brick, upen which it
is removed by a boy, who places it on a light barrow of a particular construction, which being loaded
with a certain number of bricks, they are sprinkled with sand, and wheeled to the hacks. The hacks
for drying are each wide enough for two bricks to be placed edgewise across, with a passage between
the heads for the admission of the air, to facilitate the circulation of which the bricks are usually laid
in an angular direction. The hacks are usually carried eight bricks high; the bottom bricks at the ends
are usually old ones. In showery weather the hacks must be carefully covered with wheat or rye straw,
unless sheds or roofs be built over the hacks, as is done in some parts of the country, but in London
this is impracticable, from the very great extent of the grounds. In fine weather the bricks will be
ready for turning in a few days, in doing which they are reset more open than at first, and in six or
eight days more they will be ready for burning. In the vicinity of London bricks are commonly burned
in clamps. In building the clamps, the bricks are laid after the manner of arches in the kilns, with a
vacancy between every two bricks for the fire to play through. The flue is about the width of a brick,
carried straight up on both sides for about three feet; it is then nearly filled with dry bavins or wood,
on which is laid a covering of sea-coal and cinders, (or, as they are termed, breeze;) the arch is then
overspanned, and layers of breeze are strewed over the clamp, as well as between the rows of bricks.
When the clamp is about six feet wide, another flue is made in every respect similar to the first. This
is repeated at every distance of six feet throughout the clamp, which, when completed, is surrounded with
old bricks, if there be any on the grounds, if not, with some of the driest of the unbaked ones reserved
for the purpose; on the top of all, a thick layer of breeze is laid. The wood is then kindled, which sets
fire to the coal and when all is consumed, which will be in about twenty or thirty days if the weather
be tolerable, the bricks are concluded to be sufficiently burned. To prevent the fire burning too furiously,
the mouths of the flues are stopped with old bricks, and the outside of the whole clamp plastered with
clay and against any side particularly exposed to the rain, &c., screens are laid, made of reeds worked
into frames about six feet high. and of a width to admit of being moved about with ease. This is the
mode of manufacturing the ordinary descriptions of bricks; but the superior sort, termed washed malms
or marls, are tempered with greater care and attention. For this purpose a circular recess is built about
four feet high, and from ten to twelve feet diameter, paved at bottom, with a horse-wheel placed in its
centre, from which a beam extends to the outside for the horse to turn it by. The earth is then raised
to a level with the top of the recess, and forms a platform for the horse to walk upon. Contiguous to
the recess a. well is formed for supplying the recess with water, which is raised by a pump worked by
the horse-wheel A harrow made to fit the interior of the recess, thick set with long iron teeth, and
well loaded, is chained to the beam of the wheel to which the horse is harnessed. The soil prepared
in the heap in the usual manner is brought in barrows, and distributed regularly round the recess, and
a quantity of chalk is added, and a certain portion of water; and the horse being set in motion, drags
the harrow, which forces its way into the soil, admits the water into it, and by tearing and separating
the particles, not only mixes the ingredients, but also affords an opportunity for stones and other heavy
matters to fall to the bottom. Fresh clay, chalk, and water, continue to be added until the recess is
full. On one side of the recess, and as near it as possible, several hollow square pits are prepared about
18 inches or 2 feet deep. The soil, reduced to a kind of liquid paste, is discharged from the recess by
a sluice, and conveyed by wooden troughs to the pits. In these pits the fluid soil diffuses itself, settling
of an equal thickness, and remains until wanted for use, the superfluous moisture being drained or
evaporated away by exposure to the atmosphere. The remainder of the process is the same as for the
common sort of bricks. In the country, bricks are always burned in kilns, whereby much waste is prevented,
less fuel is consumed, and the bricks are more expeditiously burned. A kiln is usually 13 feet long by 10
feet 6 inches wide, about 12 feet in height, and will burn 20,000 bricks at a time. The walls are about
14 inches square, and incline inwards towards the top. The bricks are set on flat arches, having holes
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BRICK-MAKING.
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left between them resembling lattice-work. The bricks being set in the kilnf, and covered with pieces
of broken bricks or tiles, some wood is put in and kindled to dry them gradually; this is continued till
the bricks are pretty dry, which is known by the smoke turning from a darkish to a transparent color.
The burning then takes place, and is effected by putting in brushwood, furze, heath, fagots, &c.; but
before these are put in, the mouths of the kiln are stopped with pieces of brick called shinlog, piled
one upon another, and closed over with wet brick-earth This shinlog is carried just high enough to
leave room sufficient to thrust in a fagot at a time; the fire is then made up, and continued till the
arches assume a whitish appearance, and the flames appear through the top of the kiln, upon which the
fire is slackened, and the kiln cooled by degrees. This process is continued, alternately heating and
slackening, till the bricks are thoroughly burned, which is usually in the space of forty-eight hours.
Many attempts have been made of late years to supersede, by the aid of machinery, a portion of the
manual labor now employed in the manufacture of bricks; and although only the most recent of the
machines invented for this urpose have been found to answer in practice, several of them are
worthy of notice. The engraving below represents Messrs. Choice & Gibson's brick-making machine.
a a a a is an upright frame, with cross-beams at top and bottom; bc are two vertical shafts, carrying two
horizontal spur-wheels d and e, the teeth of which take into one another; these are put in motion by the
horse-shaft f, or any other convenient power. Near the bottom of the shaft b is fixed a large cast-iron
collar g, having three deep mortises; into each of these the end of an iron arm h is fitted, with a belt
588.
9.
m
passing through them to form a centre, as in a hinge-joint. To the other extremity of each of the arms
h is firmly fixed, by screw-bolts, a cast-iron mould-box i, having three divisions for three bricks, in which
work three stocks or false bottoms, having upright bolts passing through holes in the top. By the rev-
olution of the shaft, these mould-boxes, with their arms, are successively carried up and over the
recrs k k k; which form circular curves in the plan, and appear EO in the perspective, but are in reality
24
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BRICK-MAKING.
inclined planes. At l, near the bottom of the shaft, is a small bevelled wheel, which actuates a pinior.
fixed on the spindle of the drum-wheel m that passes under the floor of the machine; an endless strap
passing round the drum m, and another placed at the required distance, continually carries the bricks
forward to their destination as fast as they are made, and deposited upon it. o is a crank or lever,
attached by a joint to the framing, as shown, at the upper end of which is fixed a roller; by the revolution
of the wheel above the three circular bars or cams, rrr, attached to the wheel, successively act upon
the roller, and depress the crank o, which first raises the rod and weight q, and afterwards, as soon as the
crank is relieved of the pressure, allows it to drop and strike the mould-boxes, by which the bricks are
discharged out of them. 8 is a box of cast-iron, containing water, into which the mould-boxes dip; t is
a cushion, upon which they next fall in succession, by which the superfluous water is taken off; and is
a box of dry sand, into which the mould-boxes afterwards fall, their surfaces tecoming in consequence
slightly coated with sand previous to becoming charged with clay. The horizontal wheel e worked by d
actuates the shaft c bearing the knives in the pug-mill. At the lower end of the shaft c is fixed the
large circular revolving bottom-plate и, the periphery of which being furnished with teeth or cogs, as
shown, take into the teeth of a circular revolving plate ", over which, as the mould-box passes, the lower
surface of the bricks becomes smoothed. At x is a small frame, working up and down in a casing, with
a pulley and counterbalance weight, like a sash window; it is raised by the crank y as each mould-box
passes, when three little boards are placed across the frame by a boy, for the reception of the bricks.
When these are deposited by the means described, the frame drops below the level of the endless strap
n; the latter then receives them, and carries them off to their destination. At z is fixed a flat box,
which acts as a gage to regulate the thickness of the stratum of clay revolving upon the bottom plate n
of the pug-mill. The operation of this machine is as follows: the clay being worked in the ordinary
manner through the pug-mill, it passes out at the mouth, (not shown, being on the opposite side,) from
thence under a flap which partly regulates the quantity on the bottom plate, and next under the gage,
which determines it precisely. A mould-box having passed over the highest inclined plane or riser k,
first falls on the stratum of clay, and chops out three bricks, filling the moulds therewith by the false
bottoms rising up to the determined point from the pressure of the clay against them; the moulds, with
the bricks in them, then slide over the polishing plate r, (which is kept wet by water constantly dripping
upon it from a tub;) from thence the moulds pass on to the frame x, when the weight q strikes against
the protruded bolts of the false bottoms, and pushes out the bricks upon the boards on the frame; the
frame then descends two or three inches by their weight, and delivers the boards upon the endless strap,
which, being constantly in motion, carries the bricks away to be deposited on the hacks. The mould-box
being discharged, is then carried upon its roller up the first riser k, drops into the water, thence rises
again, falls upon the cushion, next into the sand-box, whence ascending again, the highest inclined plane
being duly prepared, it, falls again upon the bottom plate of the pug-mill, and chops out three more
bricks, during which period each mould-box has operated in a similar manner.
We shall now proceed to describe the brick-making machinery invented by Mr. Leahy, and erected
by him for the Patent Brick Company; it is represented in the succeeding figure. a is the main
horizontal shaft in direct communication with the steam-engine or other first mover; b is a hopper-
formed vessel, technically termed the pug-mill, in which the clay and other materials are tempered and
mixed up: it is for this purpose furnished with cross iron bars, or blades of steel; part of these are
firmly fixed to the hollow vertical shaft c, and the remainder bolted to the sides of the pug-mill, and
they are so arranged, that those fixed to the shaft cut in as they revolve between the others. The
clay is delivered into the hopper or pug-mill by an endless chain of buckets, (in the same man-
ner as ballast is raised;) it is then cut up and tempered by the knives and bars in the pug-mill, and
gradually descending, it falls, or rather is forced by the superincumbent pressure upon the circular
inclined plane d, which consists of a single thread or spiral turn of a very large screw, occupying the
whole internal space of the lower cylindrical end of the mill, where it is exhibited in section. This
screw or circular inclined plane is fixed to the central shaft passing longitudinally the hollow shaft, and
a slow reversed motion is given to it, by means of an intermediate wheel acting upon pinions in the
upper part of the frame. The blades on the hollow shaft revolve in the pug-mill at the rate of fifteen
turns in a minute, grinding and dividing the materials much more completely than in the ordinary mode
of brick-making. In this attenuated state the materials are forced upon the circular inclined plane of
the screw, and as this slowly revolves in a contrary direction at the rate of five turns in a minute, it
takes hold of the clay, (by a peculiar adaptation not easily described,) and forces it out of the mill in
a very compact state, into a receptacle below: of this. one side is always in immediate contact with the
moulds, and those two sides which are at right angles to the former side are closed by iron cheeks,
between which the lever or forcing flap n acts by pressure, and fitting closely, prevents the escape of
the clay, so that it can only pass into the moulds. These moulds are placed round the periphery of a
circular frame e, made of flat iron rings, fixed upon bars or spokes, and turning upon a fixed shaft.
There are twenty-five of these moulding-boxes in one circle; but as the frame e may be of any breadth,
it may contain twice twenty-five or thrice twenty-five on the circumference of the cylinder, provided
that the engine is capable of affording sufficient power or force to cut or mould so many bricks at each
revolution. Each moulding-box is furnished with a false or moveable bottom, to which rods are
attached, for the purpose of pushing out the brick when moulded, and drawing back the bottom to its
place to receive a fresh portion of the clay. The manner in which these operations are performed is
extremely simple and ingenious. The ends of each of the moulding-box rods are bent at right angles,
and an eccentric piece f is so fixed, that, as the moulds revolve, and at the moment that the surface of
each is covered by being in contact with the clay, it gradually draws back the false bottom, and with
it the clay, which is also urged on by the circular inclined plane d; and to render the bricks solid and
compact, a powerful pressure is applied to them by means of the flap forcer n, to which a backward
and forward motion is given by the thrusting of a rod attached to a revolving crank. The moulding-
boxes, immediately they are thus filled, are subjected alternately to the action of a steel scraper, which
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BRICK-MAKING.
187
levels and smooths their surface, and is made to operate by the pressure of springs. The bricks, now
completely formed and fast in their moulds, pass downwards in their revolution, which brings the ends
of the rods under the operation of a cylindrical rolter, with grooves made round it at equal distances;
into these grooves the ends of the rods successively pass, which, in their revolution, force out the rods,
and thereby push out the bricks from the moulds on to boards placed underneath to receive them.
The bricks thus made are carried forward to the hacks or drying-house, upon an endless web or chain ii,
to which a continued motion is communicated by the revolution of the two polygonal drums or wheels
k k, placed at the requisite distance asunder. The upper part of the engraving shows a side elevation
of the machine, and the lower part a section of it; and although these views serve to give a general
idea of the construction of the apparatus, it has been impracticable to show the gearing by which the
589.
590.
%
h
name
several motions are produced we will therefore attempt to describe it as follows :-Upon the horizontal
shaft a. (which makes 21 revolutions per minute,) is fixed a toothed, bevelled wheel, which drives a
bevelled pinion on an upright shaft, (not shown; ;) nearly at the top of this a spur-wheel is fixed, which
works into a pinion fixed upon the upper end of the hollow shaft c, which carries' the knives or blades
in the pug-mill. Upon the upper end of this upright shaft is also fixed a pinion, which works into an
intermediate pinion turning upon an axis. This intermediate pinion acts upon another pinion affixed to
the internal shaft, communicating a slow and reversed motion to it, and also the circular inclined plane
affixed to it; at the lower end, on the main horizontal shaft, is fixed a spur-wheel m, which gives
motion to the crank and to the flap forcer connected to it. o, in the separate figure, gives the form of
the shelves comprising the drying apparatus,-Mr. Leahy proposing to dry bricks either by flues or by
steam, instead of ranging them in hacks exposed to the variations and inclemencies of the weather,-by
which means it is presumed that the bricks will be rendered dry enough for burning, either in kilns or
clamps, in a much shorter time than in the common method, and the process may be carried on in
winter as well as in summer. If drying by flues be resorted to. a drying-house must be furnished with
proper stages, and shelves must be provided. Around and across the lower part of these, flues framed
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188
BRICK-MAKING.
either of bricks or cast-iron are to be placed, through which flame or heated air is to be conveyed. In
drying by steam, the vapor is conveyed from the boiler through cast-iron pipes throughout the drying-
house, and boards are arranged upon stages, (similar to those in Fig. 590.) so as to leave intervals
between the rows of bricks, and to prevent their touching one another.
Nash's Patent Brick-making Machinery.
This invention, which we have now to describe, is not the only one, we believe, that has been brought
into successful operation. The leading features of Mr. Nash's mechanism consist in the application of
591.
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separate or detached moulds of a particular construction to a series of mould-boxes, which are consecu-
tively brought into action; in the employment of heaters, placed in contact with, or contiguous to, the
fresh bricks, during the process of their being moulded; and in lieu of sand, which is generally used to
prevent the adhesion of the bricks to the moulds, employing elastic absorbent substances, such as cloth
saturated with water. In the subjoined engravings, Fig. 591 represents a front elevation, and Fig. 592
an end elevation of the principal parts of the machine. A vertical shaft a is made to revolve in the
cylinder or pug-mill b, by any adequate force acting upon the bevelled wheel c. A number of broad
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BRICK-MAKING.
189
steel or iron blades d d d are attached to the shaft a, their surfaces being set at such an angle as will cause
them, during their revolution, to pass nearly in contact with the edges of two other sets of knives c e,
fixed on opposite sides of the cylinder, by which means the clay and other materials with which the
mill is charged are tempered and amalgamated, and then forced into the hopper f, fixed to the lower
extremity of the pug-mill. This hopper is divided into two equal chambers by a vertical blade or
knife, which separates the materials into equal portions, which are supplied to the moulds in a compact
state. The moulds are lodged in rectangular cavities at equal distances in the periphery of two
polygonal drums g h; these cavities are marked 1 to 12. To one face or side of the drums are
attached two toothed wheels, gearing into each other so as to revolve in opposite directions when
motion is communicated to one of them.
These wheels lying at the back of Fig. 591
592.
cannot be seen, but one of them is shown
at i in Fig. 592. The moulds, after being
filled with the plastic material, are pushed
out nom their recesses by means of pistons
at m m, easily fitting the recesses, and
sliding upon parallel rods fixed to the rims
of each drum. To each piston is attached,
by a short rod, a cross-head, sliding upon
the parallel rods, and having at each end
small anti-friction wheels pp, which, by the
motion given to the machinery, come in
contact with a larger wheel q, placed ec-
a
centrically, which thus raises the pistons,
and the moulds which lie upon them are
d
then removed by hand and emptied. Dur-
ing this latter process the emptied mould-
-
receiver will have passed over the centre
of the eccentric wheel q, and the piston
-
will be descending when the attendant
places the emptied mould in its former sit-
uation, to be filled again from the hopper
as it passes under it. Between each of
0
the rectangular mould-boxes are formed a
a
series of wedge-shaped boxes, termed by
the patentees hollow sectors," into each
of which is placed a red-hot iron, the object
of which is to expel the superfluous moist-
ure from the newly-formed brick, &c., in
order that the manufacture may be con-
ducted in the winter as well as the sum-
mer. These irons are heated in the kiln-
II
fires. The axis of the polygonal drums re-
volve in plummer-blocks, supported upon a
strong frame s; but as the polygonal drums
revolve in close contact, the plummer-
blocks are free to slide in grooves in the
frame, and the wheels are kept in contact
by the action of strong helical springs t,
which press against the plummer-blocks,
the other end of the springs abutting
against a regulating screw. In the middle
h
of, and underneath the horizontal frame 8,
is fixed a knife u, (supported in its place
by a spiral spring,) which separates the
whole or a portion of the superfluous ma-
III
terials from each mould, as the latter passes
over the edge of the former. As some re-
dundancy of material may still be left after
the operation of the knife и, the exposed
surface of the moulds in motion undergoes
a similar treatment from two other knives
vv, fixed to the foundation plate 10 of the
y
machine. A trough or cistern k k, contain-
ing water, is placed under each of the
drums, the lowest sides of which come in
contact with a cylinder y, covered with
strong coarse cloth or other suitable absorbent substance, which, as it revolves, takes up the water and
delivers it to the moulds, as before mentioned. These cylinders are mounted on elastic bearings, and
derive their motion from pinions on their axes, actuated by the toothed wheels on the drums. In the
centre of the foundation plate there is a cavity, or pit,' for the reception of the superfluous clay or other
materials, which are removed at pleasure. The pug-mill has a door in it, for the convenience of cleaning
it out when requisite; and the whole of the upper part of the machine is supported by three columns
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BRICK-MAKING.
222. The polygonal drums are driven by a set of wheels lying at the back of Fig. 591, and therefore
in that figure shown by dotted circles. No. L is a band-wheel, which drives, by a pinicn II, the two
whecls III and IV, on the axes of the driving gearing, into each other, and turning in opposite directions.
Those two wheels must have involute teeth, as their point of contact becomes variable by the move-
ment of the axes of the drums. In case of negligence on the part of the boys, or other attendants of
the machine, in not removing the bricks or tiles after the moulds containing them have passed the
centre of the eccentric wheel, they fall back into their former position, and pass round to the place of
delivery, as before, without any damage whatever being done to the machine.
Having explained the general arrangement and operation of the machine, there remains to be
described the construction of the detached moulds. Fig. 598 represents a side view, and Fig. 594 an
end view of one of these. The ends
of the mould 18, 18, are made of
593.
594.
wood, plated at the edges with iron,
o
0
and fastened on by screws, as seen
18
18
in Fig. 593. The bottom 19, is also
of wood, but cased in a strong frame
0
©
18
of cast-iron, and its two extremi-
ties are jointed to the ends 18, 18,
o
22
1
so as to open only a little way, for
19
allowing the brick to separate freely
21
21
from it upon inverting the mould
This effect is facilitated by lining the interior of the mould with cloth, which, although constantly in a
wet state, admits air to pass through its interstices when the clay is forced into the mould, 80 that
when the brick is afterwards forced out, the moisture of the cloth, and the spring of the confined air,
delivers the brick uniformly clean, without the adhesion of any clay. It will be observed that the two
ends 18 of the mould have each a cavity; these cavities receive the fingers of the workman when he
takes hold of the mould, which he afterwards inverts, drawing back the ends 18 at the instant, and
pressing with his thumb upon the screw-heads 21, 21, the other ends of which are attached to a plate 22
underneath the cloth lining of the bottom, as shown by dots, causing the brick to be immediately
disengaged. The two sides of the brick not included in the detached mould are formed by the par-
tition between the mould-boxes and the hollow sectors. The forms and dimensions of the detached
moulds are varied according to the nature of the articles to be produced therefrom. For adapting the
machine to make tiles, or other articles of a greater length than a brick, two moveable blocks, which
usually lie inside the hopper, to contract its lower dimensions, are taken out. In the making of drain
tiles, and other articles having cavities within them, jointed horses or cores are employed; the plastic
matter is forced around them by the action of the machine in the same manner as in forming a brick,
and the subsequent operations are also the same, except that in the removal or delivery of such tiles
from their moulds, suitable adaptations are made to prevent their being pressed or even touched by the
hand. The annexed Fig. 595 exhibits
another arrangement employed by Mr.
595.
Nash for making flat tiles, flooring tiles,
&c., of any required breadth and thick-
ness. This cut only represents the
b
lower part of the machine, the upper
being the same as in the previously-
described apparatus. To the bottom
of the pug-mill is fixed a funnel-shaped
z
hopper 23, the materials in which, after
23
being forced through a mouth 24,
formed of the required shape, are re-
25
ceived upon boards 25, and when cut
27
to the proper length, are removed to
24
26
sheds for drying. In order to equalize
the surface of the clay after it has come
out of the hopper, a roller 26, turning
in bearings on a curved arm, which is
fixed to a hinge-joint, gives to the ma-
27
terial any pressure that may be re-
S
S
quired, by loading it accordingly. The
dotted lines 27, 27, in the same figure,
exhibit another funnel-shaped hopper,
for the purpose of making pipes or
28
tubes, by means of a centre core 28,
between which and the cylindrical con-
tinuation of the hopper, the material is
forced by the action of the pug-mill,
and produces a tube, which, after having
made a certain length of, is cut off, the
tube being turned round, to render the
inside smooth previously to its being
removed. The patentee states that this machine may be used with either one or two horse power;
that when used with one horse power, the product is about 700 per hour, or 8000 per day to do which
requires the services of two men and eight boys, occasioning an expense not exceeding two shillings and
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BRICK-MAKING.
101
sixpence per 1000. With two horse power employed, the production is double, or 16,000 per day; but
the quality of the bricks, which the editor has seen, is equal to those which are usually finished by
grinding the surfaces by hand. The saving of labor in the production is about two shillings per 1000;
but the quality rendering them worth five shillings per 1000 more in the market, the advantage of
making by the machine, where good bricks are required, is equal to seven shillings per 1000.
BRICKS AND TILES, Machinery for the manufacture of. The application of machinery to the
fabrication of bricks has met with considerable opposition in the diversity of physical and chemical con-
ditions of the earths used. Thus, in some localities the clay has more tenacity and aluminous properties
than in others; the mechanical powers sufficient for the last would be useless in the first.
As early as 1835, M. Terrasson had constructed a machine surpassing all previous ones in simplicity
A frame, having wires stretched across, cuts into bricks the earth which has been compressed between
a roller and planks.
M. Carville has invented a machine which simultaneously bruises and divides the earth, moulds and
throws off the bricks; it may be applied to the fabrication of tiles and other earthen ware.
Description of M. Carville's Machine, Figs. 596 to 604.
DIVISION AND KNEADING OF THE EARTHS-The earths used are clays, requiring sometimes sand or
aluminous compounds. The mixture is the most difficult part in all the process of brick-making. To
this end M. Carville uses a cylindrical barrel A, with a flat bottom; its upper part is opened in order to
introduce the material. An axis B, also vertical, to which a rotary motion is imparted by a horse har-
nessed to the beam C, through the medium of the cast-iron socket a, (see Fig. 596, which is a vertical
section through the middle of the machine.) This axis rests against two pillows, one adapted to a beam
b, which unites the opposite sides of the machine, and the other upon an inferior cross-beam. This axis
is provided with several flat iron branches d, which being fixed perpendicularly to the axis, their fuces
have an inclination of 45°. On these there are sharp-edged knives, to divide and knead the clay during
their rotation; thus the earth is well divided before reaching the inferior part of the barrel. The
branches ef, stouter than the former, but without knives, are attached at the very extremity of the axis,
and receive from it a rotary motion, during which they press against the earth, forcing it out through
the orifice g. The size of this orifice depends on the quantity needed to fill the moulds; the iron sliding-
door h regulates this orifice.
This method for dividing and kneading is applied to the fabrication of earthen ware, porcelains, etc.
MOULDING AND CASTING OFF THE BRICKS.-It is specially in these functions that M. Carville's machine
excels all others. He uses a series of moulds in cast-iron, forming an endless chain D, constantly moving
these moulds successively pass beneath the aperture through which the moistened earth is pressed, in
order to receive it. Each link forms a rectangular frame, composed of four moulds, which have the
precise dimensions of the bricks. Figs. 597, 598, 599, show a plan and transverse section of this chain.
Two wheels, with each four arms E, are situated on either side at the extremity of the apparatus.
The iron bars i support the limbs and impart to them the movement of rotation communicated by the
spur-wheel F; the arrows indicate the direction in which they are to move Fig. 596, so that the moulds
are carried under the roller G after they are filled with earth.
This roller is of cast-iron, turning round a horizontal iron axis, set in motion by the beam C. Its office
is to compress the earth in the moulds as it is received from the barrel. But as these moulds have nc
bottom, a moveable flooring is adapted to them to serve as such; it is made of strong sheet-iron j, the
pieces approaching each other at distances proportional to the length of the bricks, and hooked to an
endless chain passing over the rollers k; one of these rotates, giving to the chain a motion equal to the
speed of the moulds. These must be nearly horizontal, when they pass beneath the barrel to give
them this direction, a number of wooden rollers H support the iron plates. The axes of these rollers are
of iron, freely turning on pillows, Fig. 600.
The clay being thus moulded and pressed, soon meets the blades l, made of steel or cast-iron, which
shave the two horizontal and parallel faces of the moulds, levelling and polishing the bricks.
The clay is prevented from adhering to the surface of the rollers by the water slowly falling from the
vessel I.
A wooden hopper J, containing fine and dry sand, sprinkles the bricks as they pass beneath l; a small
fluted cylinder m, is adapted to the base of the hopper to allow the sand to come out-but in small
quantity this cylinder is rotated by means of a pulley and strap, or a small endless chain.
As soon as the bricks have passed the polishing blades, they are taken out of the moulds. This is
ingeniously done by the simple process of M. Carville. Two pieces of cast-iron K, having a superficial
dimension equal to that of the section of the mould, which they completely fill, are attached to a single
vertical beam L, which is suspended to another beam M, the other extremity of which being balanced
by a counterpoise, this is prevented from falling by a board N.
To the axis of the beam M a vertical branch n is adapted this receives a movement of oscillation,
depending on the speed of the endless chain of moulds. To this end, this last is provided with little
knobs o, Fig. 598, which meet and push successively a horizontal lever r, Fig. 599, fixed to the vertical
axis g. To the superior part of this axis is attached the pulley r, Fig. 596, to the circumference of which
is hooked the small chain O, whose other extremity is fastened to the pulley r', freely rotating round
the iron pin P.
Thus when one of the knobs o is in contact with the inferior lever p, it pushes it in the direction of
the chain, causing the vertical axis q to turn; the pulley attached to q turns also, carrying along the
chain O, and since the extremity of the vertical branch " is engaged in one of its links, it is drawn by
it: therefore the axis carrying it oscillates, and also the beam M; L descends, pushing the lumps K into
the two corresponding moulds, thrusting the bricks on a moveable floor j'. The weight attached to the
beam M causes L to rise, as soon as the lever is no longer acted on by the eminence o.
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192
596.
BRIDGE.
193
To bring back to its original position the beam L, a cord is attached to its lower extremity, passing
through the pulleys 8 s', and having a small counterpoise fastened to its other end.
The chain, going all the time, plunges into a reservoir of water Q, which extends its whole length, to
wash the moulds. Following the direction indicated by the arrows, it passes under the hopper R, where
the moulds are sprinkled with sand before reaching the barrel.
The second moveable flooring j', which receives the bricks, is composed of small plates forming an
endless chain; parallel rollers, such as H', placed in a different direction from the first, support this
chain. Their iron axes are moveable in pillows resting against oak beams S.
This flooring moves only when the beam L rises. The teeth o raise successively a short lever p',
which is attached about the middle of the short vertical axis q' ; to this is adapted a second lever n', fixed
to a small horizontal beam t, which communicates through a rope with the pulley 26. Thus, as soon as
a tooth acts on p', its axis oscillates, and its inferior lever n forces the flooring j' to advance a distance
equal to the breadth of the two bricks. The small rope passing through u has a counterpoise to bring
back the levers to their original position.
The bricks being taken off without any handling, are put up to dry. The plates are set back to the
chain j', on the side opposite to that on which the bricks were.
Description of the Machine of M. Capouillet, Figs. 605, 606, 607.
This machine consists of two cast-iron cylinders, performing the office of rollers; one is perfectly
smooth, the other is pierced over all its surface with cavities, the dimension of which depends on the
size of the bricks to be made: pistons are made to fit into these cavities. These pistons receive an
alternative movement equal to the thickness of a brick.
CONSTRUCTION OF THE CYLLNDERS-The first cylinder A is solid and smooth; its diameter is 7.31 feet,
and its breadth is 7.47 feet. It has an axis of wrought-iron B, turning in pillows with screws a. It
receives its motion from the second cylinder, through a straight-toothed wheel C, whose inner diameter
is precisely that of the external cylinder.
The second cylinder A'is of the same dimensions with the first, but whose circumference contains a great
number of rectangular cavities, having only 0-039 feet between each, and of sufficient depth to contain
each the thickness of a brick and of a metallic piston b. It has also a horizontal axis of wrought-iron
B', of equal length with the preceding. It also is provided with an axis C' of equal diameter with C,
with which it is engaged; the pinion M communicates motion to it.
The pistons b are rectangular, their dimensions in length and breadth being equal to the bricks;
they are free in the cavities, but closely fitting a cylindrical rod is attached to them.
MOULDING THE BRICKS.-The clay being prepared, is brought into a rectangular box D, extending
as far as the two cylinders, between which the earth falls and is carried away by them. The quantity
is regulated by a slide adapted to the box, whose height must not be less than 6.50 feet. By its side
is placed a hopper E, containing dry fine sand to be sprinkled on the cylinder A' before the earth enters
its cavities. The spout F regulates the direction of the sand; to it an oscillating motion is imparted by
the spokes c.
The clay, falling between the two cylinders from the box D, is pressed into the cavities of A', filling
them in succession with so much more ease as the pistons are pushed in. These pistons had previously
been forced in by the cog, which is furnished with the circumference of a strong cast-iron disk G, situated
at the right of the cylinder, and having an iron axis. These cogs are disposed as in a cog-wheel, and
engaging into the cavities of the cylinder, they push the pistons within the cylinder.
An eccentric of cast-iron H is contained within A', freely turning round on its axis, in order to force
the pistons from within out, thus forcing the bricks away. The curve of this eccentric must be calcu-
lated to give the pistons play only the thickness of a brick. Fig. 605 gives an external elevation of the
apparatus, and also a part of the vertical section, showing the disposition of the pistons.
Two scrapers dd, adapted to iron levers, which oscillate round the common axis f, and which have
counterpoise e', serve to keep the surface of the cylinders smooth and clean.
TRANSPORTATION OF THE BRICKS-The horizontal boards I, receive the bricks as they are forced out of
the moulding cylinder; they are moved with a speed somewhat greater than the cylinders, in order to
leave a small space between the bricks. Their direction is from left to right.
These boards are carried by small cylindrical rollers J of cast-iron, the axes of which rest on collars g',
pinned on the sleepers, as seen in the horizontal section, Fig. 607. The toothed-wheel k, in which an
endless chain h is engaged. transmits to them the motion communicated to it by the wheel which is
placed on one of the rollers, to which the small pinion L is adapted. This last is engaged in the prin-
cipal pinion M, whose axis is turned by the prime mover which may be a hydraulic wheel, a steam-
engine, or a horizontal beam turned by a horse.
608.
BRIDGE. A very common engineer-
ing expedient employed for passing over
rivers, canals, and roads. Rivers of great
width were not often crossed by bridges
formerly, but ferries were usually estab-
lished, at convenient spots, for the pur-
poses of communication, (the sites of most
river bridges were formerly occupied by
ferries,) and shallow streams were com-
monly forded. The erection of a bridge
over a river occasions a great increase of
traffic in the line of route, as may be natu-
rally anticipated, in common with all
Elevation of the Rialto Bridge.
schemes for facilitating conveyance.
25
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194
BRIDGE.
The bridges employed in modern times are constructed after various methods, but arches are mostly
used. In most cases the road is carried over at once by stone or brick arches, or by iron or wood beams
thrown across and trussed, according to the span; the road is sometimes suspended from inverted bows
609.
Details of one of the arches and centreing of Waterloo Bridge.
by rods, being usually formed of iron, which are supported upon stone piers at each end, and from
thence carried down and secured in the ground, which are called iron suspension bridges.
Among modern bridges may be mentioned the Rialto Bridge, over the Grand Canal, at Venice, which
was commenced in 1588, by Michael Angelo, and is considered to be a very beautiful structure.
The bridge across the Seine, at Neuilly, built between the years 1768 and 1780, by Péronett, is a very
celebrated structure; it is a level bridge, consisting of five elliptic arches, each of 128 feet span, and 32
feet rise.
Waterloo Bridge, London, by Rennie, is considered a masterpiece. It was commenced in 1810, and
is also a level bridge, having nine arches, each 120 feet span, and 35 feet rise, and it is 42 feet 4 inches
wide between the parapets.
610.
Elevation of one of the arches of Neuilly Bridge.
London Bridge, by the same engineer, is a fine work; and, together with the last, form excellent
specimens of masonry, being constructed of granite.
Timber bridges have been much more generally employed since the introduction of the many inven-
tions for preserving timber, as the material offers very great advantages. In wooden bridges of small
span the pieces running from pier to pier are termed sleepers, or string-pieces, which support the cross-
joists, on which the planking is laid small pieces of wood are sometimes introduced under the string-
pieces to shorten the bearing, which are termed bolsters, or corbels.
The American system of forming bridges and viaducts by laminating timber arches, has been lately
introduced into England. The Ouse-burn Viaduct is 108 feet high, and consists of five arches, each 116
611.
Transverse section of Neuilly Bridge.
feet span, with two stone arches at each end, 45 feet span; and the Wellington Dean consists of seven
arches, each 120 feet span, the height up to the roadway being 82 feet. The piers and abutments are
of stone, and each arch consists of three segmental ribs, each rib being composed of thirty 3-inch deck-
deals, being two deals in width and fifteen in height; they vary in length from 20 to 45 feet the
first course is formed of two deals in width, as before stated, bent over a light centre; the next course
consists of one deal and two half ones, and 80 on until the whole rib is formed, the ends breaking joint
with each other; and they are connected together by 3-inch oak-trenails, each passing through three of
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612.
Elevation of Schuylkill Bridge. Longitudinal Section.
BRIDGE.
613.
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Elevation of the Upper Schuylkill Bridge. Longitudinal Section.
195
196
BUFFING APPARATUS.
the deals: a layer of brown paper, dipped in boiling tar, is placed between the joints to prevent the
wet from injuring them, and the timbers are bedded tightly on it; the ends of each rib are let into
cast-iron shoes, which are fixed to the springing-stones of the masonry, and are secured with four long
iron bolts and run with lead, and the three ribs are connected together by diagonal braces and iron ties
the spandrels are framed as shown in the cut, and the whole of the timber is prepared to prevent decay.
614.
Elevation of centre arch of the Wellington Dean Viaduct.
There have been several arches of large span executed with timber, in Germany and in America-as
the Schuylkill Bridge, at Philadelphia, of three arches, the centre one of which is 195 feet span, and the
side ones 150 feet; also, the upper Schuylkill Bridge, of the same city, consisting of one arch, 340 feet
span, the rise being only 20 feet-the largest arch in the world.
The floods form the principal difficulties to guard against in bridges connected with rivers and canals;
and their effect upon the nearest adjacent bridges and arches should be carefully ascertained previous
to deciding upon the width of the arches or openings of the intended works. The traffic should be con-
sidered next, and sufficient width left for it between the parapets.
BRINE-PUMPS. See VARIETIES OF BOILERS and DETAILS OF ENGINES.
BRINE, Boiling Point of. See DETAILS OF ENGINES.
BRONZING. Improvements in the Brassing and Bronzing the surfaces of steel, iron, dc., by Charles
de la Salzede, of Paris. This invention consists in coating cast-iron, steel, lead, zinc, and tin, with brass
or bronze, by means of a galvanic battery. The solution to be used consists of 5,000 parts, by weight,
of distilled water, 610 parts subcarbonate of potass, 25 parts chloride of copper, 48 parts of sulphate
of zinc, 805 parts of nitrate of ammonia, and 12 parts of cyanide of potassium. The cyanide of po-
tassium is dissolved by itself, in about 120 parts of distilled water taken from the above quantity.
The other salts above mentioned (except the nitrate of ammonia) are then added to the remainder of
the water, and the mixture is heated to from 144° to 172° Fahrenheit; when they are entirely dis-
solved the nitrate of ammonia is added, and the solution allowed to stand 24 hours; the solution of the
cyanide of potassium is then added, and the whole allowed to stand till it is quite clear; the clear
solution is then to be drawn off with a siphon, and put in the decomposing-trough. The subject to be
covered with brass is then to be attached to the zinc-pole of a battery; and to the other pole of the
battery a large plate of brass is to be attached, which must be also immersed in the solution. The bat-
tery must, the patentee says, be a powerful one; he advises to use Bunsen's, or Grove's. When it is in-
tended to bronze, instead of the 48 parts of sulphate of zinc, 25 parts of chloride of tin must be used
the other ingredients are to remain the same. Another solution, recommended by the patentee, consists
of 5,000 parts of distilled water, 15 parts of chloride of copper, 35 parts of sulphate of zinc, 500 parts
of subcarbonate of potass, and 50 parts of cyanide of potassium, for brassing; and for bronzing, 12
parts of chloride of tin, instead of the 35 parts of sulphate of zinc; this solution, the patentee says,
must be used at a temperature of from 25° to 36° cent. The proportions, the patentee says, may
be varied within certain limits.
BUCKET-LADDER. See VARIETIES OF STEAM-ENGINE.
BUCKET-WHEELS. See CONSTRUCTION OF WATER-WHEELS.
BUFFING APPARATUS. A contrivance for receiving the shock of a coalition between railway-
carriages, consisting of powerful springs and framing.
The buffing apparatus first used upon the Liverpool and Manchester Railway consisted of elliptic
iron springs, or bows, of several thicknesses, placed transversely across the middle of the frame-work
of the carriage which received the shock of whatever blows or jerks the buffer-heads might receive, by
the aid of rods communicating with the same, to which method the following has been considered an
objection :-If the several carriages are not loaded equally, the frames do not range upon the same
level with each other and when this is the case, the buffer-heads consequently do not strike each other
in the centre, whereby the rods become bent, and the whole apparatus is liable to get twisted: to
remedy which Mr. Bergin, of Dublin, contrived an improved buffing apparatus for the carriages of the
Dublin and Kingstown Railway.
It is supported upon the axles of the wheels, and is totally unconnected with the frame of the car-
riage, whereby it does not partake of the rise and fall of the latter, according to the weight acting
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615.
upon the vertical springs; and two strong iron rods are passod through the
whole length of the carriage, which rest upon small rollers, to which the
buffer-heads are attached, spiral springs being wound round them, which re-
ceive the effect of all shocks, by the help of collars formed upon the rods,
and the introduction of stops to the springs.
Fig. 619 represents a cross-section of the first model made by Mr. Tucker,
under the direction of Mr. Ray, in the summer of 1844, and to which Mr.
Tucker, Mr. Bradley, and Mr. Bannester, testify as being the model marked
of B;" Fig. 617, the model made in 1845, to which Mr. Osgood, Bradley, and
Gen. Thos. W. Harvey have testified Fig. 618, a rough sketch made by Mr.
616.
617.
619.
©
618.
Fowler M. Ray's Metallic India-rubber Car-Springs and Buffing Apparatus.
Ray, in 1844, which he gave to a man about departing for England to take
out some patents, who promised to write to Ray after his arrival in that
country-which promise he has probably forgotten.
Mr. W. C. Fuller, of England, patented the above spring, in that country,
on the 23d October, 1845. He filed his enrolment April 23d, 1846, and on
the 22d October, 1846, he took out a patent in the United States, under the
title, " For Improvement in Railway Carriages," when the improvement
consisted in the spring, and not in the carriage.
By the above detail it seems clear to our minds that the invention, though
claimed by an Englishman, (Mr. Fuller,) belongs to the American, (F. M.
Section of Bergin's Buffing
Ray.)
Apparatus.
BUHL WORK. See PUNCHES.
BULLETS, manufacture of by rolling. At the Arsenal, at Woolwich, in
England, they now manufacture leaden bullets by drawing and compression. These bullets have
the advantage of being without blows or air cavities, and are rolled out of round bars of lead, which
are passed between rolls formed like the roulettes used for ornamental work on the lathe. The rolls
are constructed with hemispherical cavities, each one of which forms one-half of the ball, whilst the
correspondent cavity forms the other half; the bullets are then finished by removing the extra metal,
and being rolled together in a barrel.
BULLET WOOD. See WOODS, varieties of.
BUNG-CUTTING MACHINE. We here present two views of a machine invented by Messrs.
Dowdy & Sweet, No. 35 Cross-street, of this city. Fig. 620 is a side elevation, and Fig. 621 a view
of the cutter-stock and cutters. A is a stout table. H is a strong upright-post in the middle of the
table. To this post the cutter-shaft C is secured by proper bearings DD, to allow it to revolve. F is
a screw which passes through a bearing G, into an opening in the head of N. J is an elevating bed or
rest for the plank that is to be cut into bungs. It is fixed on a treadle J, by a foot-spring K;
when pressed upon towards L, the bung-bed is elevated through an opening in the middle of the
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BUTTON MACHINERY.
020.
F
.
D
H
c
D
B
&
H
K
I
o
table, and as the foot presses K, so is the plank fed up to the cutter till the bung is cut, when the foot
being released, the bung is driven out by a spiral spring, which will be better understood by Fig. 621.
A is the cutter-stock. It is of a cylindrical form, with an opening through the
621.
centre, and a thread a short distance at the upper end to screw in the shaft C.
In the centre of the cutter-stock is a spindle with a spiral spring on it, represented
by D. The spring does not reach to the ends of the spindle. By an open-
ing in C, the shaft is allowed to pass into it, when the plank is fed into the
c
cutters; but when the bung is cut, this spiral spring in the centre of the cutter-
stock recoils as the feed-table is lowered, and throws out the cut bung. This is
the object and use of the interior spiral spring and spindle. GFH are the cut-
ters. Each is a distinct piece, and each performs a different office. They are all
set on to the cutter-stock, which is turned on the outside, leaving them to sit
around it like a ring, where they are covered with a snug collar B, and a screw
E E, for each cutter, secures them to the cutter-stock. The inside of the cutters
is like a cup, and they are arranged almost like screws of different pitch. F has
two little spurs on it; one on the inner side, and the other on the outer. These
cut the cresses of the groove in the plank for the bung, when H follows after and
scoops it out, cutting on the outside of the bung. Both of these cut straight with-
out any taper. G is the taper cutter. It is graduated in the edge to the bottom
of the cutter-stock; therefore it gradually planes the taper of the bung, after the
B
OF
other two cutters have done the rough work. This makes the work easy on the
machine, which cuts out about 20 bungs per minute, hand fed, with great ease.
On the bottom of the stock, in the inside of the cutters, there is a small knife
G
H
that rims off the edge of the bung. This machine has been in operation suc-
cessfully for some time.
BUSH. A piece of metal, usually made of hard brass, and fitted into a
622.
plumber-block, in which the journal turns; they are also sometimes termed
pillows, and the blocks, pillow-blocks. The guide of a sliding-rod is also term-
ed a bush. Thus, in Fig. 622, A is the piston-rod, B B the bush.
B
BUSHES, metal for lining. See DETAILS OF ENGINES.
A
BUTTON MACHINERY. Buttons may be divided into two general
classes,-those with shanks, or loops of metal, for the purpose of attaching
B
them to garments, and those without shanks; and each class is manu-
factured from a great variety of materials, and by a variety of methods. Of
buttons with shanks the greater number are composed of metal, although glass and mother-of-pearl
are also employed for the purpose. Metal buttons are formed in two different ways, the blanks or bases
of the buttons being either cast in a mould, or stamped out of a sheet of metal; the former method is
gen rally employed for making white metal-buttons, and the latter for plated and gilt buttons. To cast
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buttons, a great number of impressions of the pattern of the button are taken in sand, and in the cen-
tre of each impression is inserted a shank, the ends of which project a little above the surface of the
sand, and fused metal is poured over the mould. When cool, the buttons are taken from the moulds,
and after being cleansed from sand by brushing, are placed in lathes, the edges are turned, the face and
back smoothed, and the projecting part of the shank also turned. The buttons are then polished by
rubbing the faces upon a board spread with rotten-stone of different degrees of fineness, and afterwards by
being held against a revolving board covered with leather, upon which is spread a very fine powder of
the same material; finally, they are arranged on a sieve or grating of wire, and immersed in a boiling
solution of granulated tin and cream of tartar, by which means their surfaces become covered with a
thin layer or wash of the metal, which improves their whiteness without injuring their polish. The
blanks of plated buttons are cut by a fly-press out of copperplate, coated on one side with silver.
They are then annealed in a furnace, and afterwards stamped by the descent of a weight, as in a pile-
driving machine, the die being fixed in the lower surface of the weight. The soldering of the shank is
performed on each button separately, by the flame of a lamp and a blowpipe: the edges of plain but-
tons are next filed smooth in a lathe, and the buttons are afterwards boiled in a solution of cream of
tartar and silver; they are then placed in a lathe, and the backs brushed, and afterwards burnished
with blood-stone. The metal used for gilt buttons is an alloy of copper and zinc. This metal is rolled
out into sheets, and the blanks stamped out, which are then planished, if intended for plain buttons; but
if for figured buttons, the impression is now given. The shanks are next attached, which is effected as
follows each blank is furnished with a pair of small spring tweezers, which hold the shank down upon
it on the proper place, and a small quantity of solder and resin is applied to each. They are then ex-
posed upon an iron plate to a heat sufficient to melt the solder, by which the shank becomes fixed to
the button; and whilst still warm they are plunged into nitric acid, to remove the oxide formed on the
surface by the heat employed in soldering the shanks. They are then placed in a lathe, the edges rounded,
and the surfaces rough-burnished, which renders them ready for gilding. Five grains of gold are fixed by
act of parliament, in England, as the least quantity to be employed in gilding a gross of buttons of one
inch in diameter. An amalgam is formed of gold and mercury, and the buttons are placed in an earth-
en vessel along with the amalgam, together with as much aquafortis as will moisten the whole, and the
mixture is stirred with a brush until the buttons are completely whitened. To dissipate the quicksilver
the buttons are shaken in an iron pan, placed over a fire, until the quicksilver begins to melt, when they
are thrown into a felt cap, and stirred with a brush, to spread the amalgam equally over their surfaces;
after which, they are returned to the pan, and the mercury volatilized completely by the increased heat,
leaving the gold evenly spread in a thin film over the surface of the buttons; they are then burnished
in a lathe, which completes the operation. The better sort of buttons undergo the gilding process
twice or thrice, and are distinguished accordingly as "double" or treble gilt." Glass buttons are
formed of glass compressed, while in the fluid state, in moulds, in which the shank is inserted, and when
the glass becomes cold, the shank is firmly retained in its place. In mother-of-pearl buttons the meth-
od of inserting the shank is extremely ingenious: a hole is drilled at the back, and undercut-that is,
larger at the bottom than at top; and the shank being driven in by a steady stroke, its extremity ex-
pands; on striking against the bottom of the hole, it becomes firmly riveted into the button, forming a
kind of dove-tail joint.
Buttons without shanks are of two kinds; the first are simply disks of horn, bone, wood, or other
material, with four holes drilled through the face, for the purpose of sewing them to the garment.
Horn buttons of this description are made from cow-hoofs by pressing them into heated moulds. The
hoofs having been boiled in water until they are soft, are first cut into plates of the requisite thickness,
and after into squares of the size of the diameter of the button, and afterwards reduced to an octag-
onal form by cutting off the corners. They are then dyed black by immersing them in a caldron of
logwood and copperas mixed. A quantity of moulds somewhat resembling bullet-moulds, and each
furnished with a number of steel dies, are then heated a little above the point of boiling water, and
one of the octagonal pieces of horn is placed between each pair of dies, and the mould being shut is
compressed in a small screw-press, and in a few minutes, the horn becoming softened by the heat,
receives the impression of the die, after which the edges are clipped off by shears, and then rounded
in a lathe. The holes in buttons of this description are drilled by means of a lathe, represented in the
annexed engraving. Four spindles, of which two only, a a, can be seen, are supported in bearings at b,
623.
c
a
D
h
b
g
0
a
D=
d
and by the centre points cc are made to revolve with great velocity by means of two bands d d passing
over pulleys e e fixed upon each of the spindles, each band driving two spindles, and receiving motion
from a wheel worked by a treadle. At the end of each of the spindles a, is a hook uniting them to
four other spindles ff by similar hooks at one end, the other end of the spindles passing through four
small holes in the plate g, and the projecting points being formed into small drills. The button is placed
in a concave rest h, and pushed forward against the drills by a piece of wood. The standard g can be
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BYRNEGRAPH.
exchanged for another with holes more or less apart, and the rest h can be set at any height to suit
different-sized buttons. As the spindle-holes in the plate g are nearer together than the holes in the
standard b, the spindles ff converge; the hooks in the spindles are therefore necessary to form a uni-
versal joint. The second description of buttons without shanks consists of thin disks of wood or bone,
called moulds, covered with silk, cloth, or other similar materials. The bone for the moulds is made
from refuse chips of bone sawed into thin flakes, and brought into a circular form by two operations,
illustrated by the accompanying engraving. On one end of the spindle a, which revolves in bearings
624.
a
d
b
6
l
m
g
at b b, is screwed a tool c, and on the other are two collars dd, between which a forked lever e embraces
the shaft, the fulcrum of which is at f. The spindle a is put in rapid motion by a band g passing over
the pulley h, and over a band-wheel worked by a treadle; and the workman, holding the material i for
the mould in his right hand, against a piece of wood k firmly held down in the iron standard I by two
screws, by means of the lever held in his left hand, he advances the tool c against the material i of
the mould the central pin of the tool drills a hole through the centre of the intended mould, whilst
the other two points describe a deep circle cutting half through the thickness of the material, and the
flat surface is cut smooth by the intermediate parts of the tool. The tool is then drawn back a little
by the lever e, and the material shifted to bring a fresh portion of the surface opposite the tool, and
when as many moulds as the plate of the material will afford, are thus half cut through, the other side
is presented to the tool, and the central point of it being inserted in the hole made in the first part of
the operation, the other two teeth cut another deep circle exactly opposite the former one through the
remaining substance of the material, and the mould is left sticking on the tool; by drawing back the
lever e the tool recedes, and the mould, meeting a fixed iron plate, is pushed off the tool, and falls into
a small box m.
Covered buttons having come into very general use, various improvements have been introduced
in the manufacture of them, and patents for this purpose
625.
have been granted to various parties. The following is Mr.
Sanders' method of making covered buttons: a piece of the
material with which the mould is to be covered is cut of a
a
circular shape, somewhat larger than the intended button; upon
this is placed a disk of card of the exact size of the button, and
b
b
next a disk of paper coated with an adhesive composition, which
c
will become soft and sticky by heat and upon these is laid a
button-mould e, having four holes, through which threads or
a
a
strings have been passed to form the flexible shank. These
circular disks being put together, are then laid over a cylindrical
hole in a metal block a; this hole being exactly the size of the
intended button, and the covering of the button being larger
than the hole, when the disks are pushed down into the hole, the material of the covering will wrinkle
up on the edges round the other disks. The tube bb is then introduced into the cylindrical hole, and
its lower edge being bevelled inwards, will, as it is pressed down, gather the plaits of the cloth on the
edge of the button; towards the centre is a metal ring or collar c, having teeth round its edge, some-
what like a crown-saw, which is now passed down the tube b, and driven with considerable force by the
punch d, and the block a having been previously heated, the adhesive matter will be softened, and cause
the several disks to stick together, which, when taken out and become cold, will be very firm and retain
its shape.
BUTTON-WOOD. See WOODS, varieties of.
BUTTS OF CROSS-TAIL, Rules for proportioning. See DIMENSIONS OF ENGINES.
BYRNEGRAPH, OR NEW PROPORTIONAL COMPASSES: Invented by Oliver Byrne, the
Editor of this Dictionary. Proportional Compasses have been very defective and expensive instru-
ments, easily disarranged and almost impossible to be repaired. If the points of a proportional com-
pass were disturbed in the least by constant use, sharpening, or accident, it was rendered wholely useless.
Besides, each of these instruments was constructed from a number of experiments, and not by rule or
on mathematical principles: 80 that no two proportional compasses were divided alike; or in other
words, there has been no certain rule to determine the positions of the several divisions of the lines on
the instrument. Mathematical instrument-makers in this, as in many other instances, determined the
divisions by guess, or what is commonly called the rule of thumb," circumstances that not only left
the dividing inaccurate and subject to change, but also made the number of divisions very few, merely
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BYRNEGRAPH.
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those answering to the whole numbers 1, 2, 3, 4, dc., which were intended to correspond with 80 many
times the length, surface, or solidity of some particular unit of magnitude.
The new proportional compasses, or as it has been termed, The Byrnegraph," not only remedies the
defects of the old proportional compasses, but also extends the application of an instrument of 80 much
importance to the engineer, the artist, the architect, and the amateur, in every department of applied
mathematics, when its results can be relied on with confidence. The fact is, this mathematical instru-
ment, from being one of the most uncertain, scarcely deserving the appellation mathematical," from
the principles upon which it has been constructed, and the limited range of its application, by one or
two simple contrivances, will now be found based on principles purely mathematical, and quite as cer-
tain and as extensive in its results as the Sextant or Theodolite.
The framework of this instrument may be made to assume different proportions and forms for the
sake of ornament, compactness, or convenience, according to the fancy or design of the maker; the first
completed was constructed by Cary, 181 Strand, London, and explained at York, before the British
Association, in 1844. A view of the instrument, which we shall describe, is given in Fig. 626 it differs
but little from that constructed, according to the directions of the inventor, by Désiré Lebrun of Paris.
626.
24
A
B
8
The two boxes E pq, F pq, are 80 adapted to the beams A B, CD, that they may be moved together
by sliding to any part, and fixed in that position by tightening the clamp-screws E and F. When the
moveable centre E q F, is clamped in any position, the instrument turns on an imaginary line or axis
passing through EF, perpendicular to a plane passing through P q, the junction of the boxes E pq,
F Pq the friction of the planes meeting at pq renders the motion uniform. Connected with the brass
boxes at K and L are two points of the instrument meeting at x: at K and L there are two clamp-
screws to fix the boxes, which must be moved together. When the points are in their proper places,
the proportions of the instrument that we are describing are these :-Suppose st = 1, then tu = 24, and
uv = 5. The points at x are represented in proper adjustment, but those at y must be moved till y comes
up to the line w, and then made fast by the clamp-screws at Q and R. When the points are worn or
broken, the boxes QR, LK, must be moved accordingly, so that the equal beams, A B, CD, exceed the
24 equal parts, in order to give the instrument sufficient range. It is also advisable that the lengths of
the points should exceed rather than fall short of the designed proportions. We shall now show how
to determine the lengths and proper positions of the points at any time; an adjustment upon which
the accuracy of the instrument very much depends.
Let the boxes Q, R, Fig. 627, be moved together until the points y just
touch a straight-edge appended at BD; then BR, the length of the points,
627.
is determined from a scale on the upper side of AB. Or the length may
24
be more accurately found by moving the centre-piece in conjunction with
R
QR, and taking the difference of the numbers pointed out by the same
B
vernier, when Q R is at BD, and when the points y fall within BD. If
this length be greater than five or any other number of equal parts allotted
Q
to the longer points, then Q R must take its fixed position accordingly; so
that not more than the designed number of equal parts may extend beyond
W, where the 24 divisions are supposed to terminate on the beam AB. In the present case the differ-
ence between 5, 50, or 500, and RB, will give the difference of Q R from W. A similar operation, will
be required to adjust the points at x. Figs. 628 and 629 show the instrument when closed and open,
viewed directly over K E R, Fig. 626; it must be always closed as in Fig. 628 while sliding, and fixing
the moveable centre EF to any required proportion, and when being used the moveable centre must
be firmly clamped.
628.
629.
For the purpose of ascertaining with great exactness the position of the moveable centre EF, Fig.
628, there may be four verniers or reading-plates, two at each side of the instrument, fixed in openings,
as m, n. From opening and shutting the instrument from time to time, the motion will require some
26
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BYRNEGRAPH.
adjustment to render it uniformly smooth, to move stiffer or easier at pleasure, and to keep steady in
any position that may be given to it, 80 that the motion may be similar to that of an ordinary pair of
compasses. This adjustment is performed by the application of a windlass turn-screw to the clamp at
one side of pq; thus the pressure on the planes that meet at pq is increased or diminished. On the
faces of the limbs of this instrument there are in general four sets of lines and divisions; the first de-
nominated the line of lines;" the second, the line of circles;" the third, the line of surfaces;" and the
fourth, the line of solids." With the assistance of the accompanying table, one or two lines of equal
parts with verniers attached will answer every purpose.
Before entering upon the use of this instrument, it may be necessary here to explain the nature of
verniers generally; which is very simple, and can be shown as follows: (see Byrne's Practical, Com-
plete, and Correct Gager, page 52.)
Any straight line or circular arc divided equally, can again be subdivided by a vernier with little
trouble, to very great minuteness: for example-let the line B be taken of any number of equal
parts whatever, and a moveable scale or vernier, V, that contains on the bevelled edge of d, 9 of the
equal parts of A B divided into 10-i. e. the 10 equal parts or spaces on the vernier are equal to 9 on
the line A B; this vernier will divide each of the former divisions into 10 equal parts.
630.
A
0
1
2
3
B
d
7
v
Let the vernier a b d or V, be moved to V', then 0 or zero, the point commencing the scale on
the vernier, has moved over 15 divisions on A b and something more, which is three-tenths-found on
the vernier by seeking where the divisions on it coincide with those on the line A B: in this case they
coincide at 3; therefore the distance on the line A B, from 0, to where 0, on the vernier rests at V', is
represented by 15:3-also from a to a', or from b to b', is 15:3: and in fact, every point of the vernier
has moved 15.3 of the divisions on A B, from its position at V to its position again at V'. Again, let
the vernier be moved along the line A B, to the position V", then we find that 0, or the first division on
the vernier, has moved 28 divisions and part of another, which is seven-tenths of it, as the division on
the vernier at 7 coincides with one on the line B; therefore, from 0, on the line AB, to where 0 on
the vernier rests at V", is 28.7, and from a to a", or from b to b", &c., is 287; as before shown with
15.3, when the vernier rested at V'. The distance on the line A B, between 0 on the vernier at V', and
0 on the vernier at V", is 287-15-3=13;4, and the distance between a' and a", or b' and b", is 13.4. Sup-
pose 11 of the equal spaces on any line, as AB, be taken, and divided into 12, for a vernier; or in other
words, to have 12 divisions on the vernier, equal to 11 on the scale upon which it moves: this vernier
divides each of the divisions upon such a scale as A B, into 12 equal parts; or, as it is said, it reads off
12ths. Again, if we take 19 equal parts on any scale, equal to 20 on a vernier, such vernier reads off
20ths; if 49 on the scale be equal to 50 on the vernier, the vernier reads off 50ths, and so on.
"The line of lines" on the instrument that we are describing, is divided into 3000 equal parts by one
of the verniers attached to the moveable centre. The reckoning commences at the extremity of the
shorter points; therefore the division marked 150 and may be read 1500, is in the middle of the line
that is, the division marked 150 is equally distant from the points at x and those at y.
There may be another set of divisions on this line marked 1, 2, 3, 4, 5, &c., and represent the ratios
1 : 1, 2 : 1, 3 : 1, 4: 1, 5: 1, &c., respectively. The division marked 1 coincides with the one marked
150. When the division on the vernier marked zero is set to 1, or 150 on the line of lines, any opening
of the compasses will be equal at both extremities. When the vernier zero is in like manner set at 2 or
100 on this line, then any line between the longer points (y, y', Fig. 629) will be twice as great as the
one between the shorter points x x'; the angle of opening remaining constant: consequently any line
taken between the longer points may be accurately divided into two equal parts by the distance be-
tween the shorter points. Further, when the zero of the vernier belonging to this line is set to the
division marked 3 or 75, the ratio of x x' to y y', at any opening will be as 1: 3, or the line between
the shorter points will be one-third of the line between the longer points. The same may be said of
the remaining continuous divisions. The positions of the integral divisions 1, 2, 3, &c., among those
marked 10, 20, 30, &c., can be readily ascertained for instance, if it were required to find the position
of the moveable centre 80 that the distances between the points may be in the ratio of 1 to 7, we have
only to divide 8000 into two parts in the ratio of 1 : 7, thus:
875
7
3000
2625
Therefore 7 on the line of lines must stand at 375 or 2625 on that line; for it will be found that
375 + 2625 = 3000
and 375 : 2625 1 : 7
This and the like proportions may be found at once by the succeeding table: the decimal of 1-7th =
142857, opposite which in the table we find 875, the division at which we find the zero of the vernier
must be set. 2625 represents the same position as 375, for one tells the distance from the shorter
points and the other from the longer; the distance between the points, as we have before observed, is
supposed to be divided into 3000 equal parts.
It may be inconvenient from the space occupied by the centre to continue this aliquot series of divi-
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BYRNEGRAPH.
203
"ions beyond 9 or 10, so that if 1-20th of a line be required, we must have recourse to the following
means; take 19-20ths of the line, and the remainder must be 1-20th: thus-
19 + 20 : 3000 20 19 1462 1538
If zero be set at 1462, or its supplement 1538, on the line of equal parts marked 10, 20, 30, &c., then
the distances between the points, in any position at one side, is 19-20ths of the distance between the
points at the other side, the compasses retaining the same angle of opening.
The position of the centre can be immediately determined by the table before alluded to: opposite
the nearest decimal to that of = -950000, we find 1462, which was before determined. We have
called 1538 the supplement of 1462, because 1462 + 1538 = 3000. Some of these supplemental ali-
quot divisions might be laid down between 100 and 150, and others of them between 150 and 90, and
marked in a contrary position to the numbers on this line which express the direct aliquot parts: thus
8 might signify 7; hence 6 signifies s; 13 signifies 13; and 80 on. However, unless for these very
large portions, it is better to calculate the position of the moveable centre for each as it may be re-
quired, the operation in all cases being so simple, especially with the table. By reading off the vernier
in any position and taking the result from 3000, we have the ratio between the lines at any angle of
opening; for example, suppose the vernier, when the centre is fixed, to show 1693, then the openings
will be as 1693 : 1807, for 1693 + 1807 = 3000.
The position of the moveable centre for the greater aliquot and supplemental divisions, may be im-
mediately determined by the following table:-
Ratios.
Centre at
Ratios.
Centre at
Ratios.
Centre at
Ratios.
Centre at
Ratios.
Centre at
1 1
1500
.1 7
375
12 13
1440
18 19
1459
24 25
1469 5
1 2
1000
1 8
333
13 14
1445
19 20
1462
25 26
1471
1 3
750
1 9
300
14 15
1448
20 21
1464
26 27
1472
1 4
600
1 10
273
15 16
1452
21 22
1465
27 28
1473
1 5
500
10 11
1428.5
16 17
1455
22 23
1467
28 29
1474
1 6
429
11 12
1435
17 18
1457
23 24
1468
29 30
1475
Thus, if the centre be set at 600, lines may be divided into four equal parts; if set at 1455, any
given line can be divided so that the whole is to one of its parts in the ratio of 17 to 16 or the whole
to the other part as 17 to 1.
L Let it be required to take 13 of any given line A B.
= decimal 136843
% = decimal 863157
1.
1.000000
A
C
B
Opposite 136843 in Table III, we find 361 or rather, opposite 136794, which is the nearest to
136843 in the table, we find 361: and opposite to the nearest to 863157 we find 1390. If the centre
be set at 1390, and the line A B taken between the longer points, then the shorter points will extend
from A to C, or %? of A B; hence CB will be 13 of AB. But this can be taken between the lesser
points if the centre be fixed at 361, and the line A B placed between the longer points. Or, by the
Rule of Three:
To lay off A B and A 0 between the points,
say,
As
82
+
95
8000
82 1889.8 nearly = 1390
95 1610'2
=
1610
To lay off A B and BC between the points,
say,
As
95
+
13
=
108
3000
13 361.1 nearly = 361
95 2638.
= 2639
II. Let it be required to take the to of a given line m p.
to = .025000
18 = 975000
m
n
p
18 1.000000
Opposite 974982, which is the nearest to .975000 in Table III, we find 1481; therefore if the centre
be set to 1481 or to 1519, its supplement, and m p taken between the longer points, m n = 39 of m p
will be the distance between the shorter: by laying off m n we also lay off 76 P the 1-40th of m p. By
the Rule of Three:
39
1481
As
39
+
40
=
79
3000
40 1519
The Line of Circles-The line marked " circles," may also be furnished with a double set of divi-
sions; one set for polygons, and the other for laying off any portion of a circle in degrees, minutes, and
decimals of a minute. When zero on the index is set to any number on the line of polygons, the
points will open in the proportion of the radius of a circle to the side of an inscribed polygon of that
number of sides; thus, if it be set to the division marked 7, and the points yy' opened to the radius
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BYRNEGRAPH.
of any circle, the opening of the points at x x' will divide the circumference into seven equal parts.
Or, the position of the centre, for any polygon from 3 to 20 sides, is given in the annexed table.
Sides.
Centre at
Sides.
Centre at
Sides.
Centre at
Sides.
Centre at
Sides.
Centre at
Sides.
Centre at
8
1902
6
1500
9
1219
12
1023
15
881
18
773
4
1757
7
1394
10
1146
13
971
16
842
19
741
5
1621
8
1301
11
1081
14
923
17
804
20
715
The use of this table is obvious, for if the vernier be set at 1394, and the radius taken between
one pair of points, the side of the required heptagon will be between the other points; and so of
other polygons.
The other equal divisions are like those already described on the line of lines, only the numbering
runs in a contrary direction, commencing to count from the extremities of the longer points. To lay
off any number of degrees, minutes, dc. find the division from the following table, opposite the natu-
ral sine of half the given angle, and set the vernier to that division; then if the diameter be taken
with the wider opening, the other opening will be the chord of the given angle, which is easily applied
to lay it off.
III. It is required to lay off an angle in the semicircle A B o
631.
equal to 136° 323 = 136° 17' 19" 88.
2)136° 17'·323
C
Nat. sine 68° 8'·6615 = 928126
The nearest number to 928126 is 928020, which is opposite
to 1444; therefore if the moveable centre be set to 1444, and
A B taken between the shorter points, which is the greater open-
ing, then BC will be the distance between the longer points, A
o
B
and the angle B = 136° 17'·323. It may be necessary to
remark, that the lines are numbered from the shorter points, 10, 20, 30
250 and from the
longer points 50, 60, 70,
290, 80 that 144·4, on the line of circles, which is numbered 50, 60,
70, &c., may be represented by 1556, as both are equally distant from the centre, for 1556 as far
exceeds 1500 as 1444 falls short of it. If the centre be fixed at 1556, and A B taken between the
longer points, then B C, the chord of 136° 17' 19". = 186° 17'·323, will be the distance between
the shorter points. The only alteration that takes place by changing the centre from 1444 to 1556 is a
change in the application of the points; the diameter was taken between the longer points when the
centre was fixed at 1444, and between the shorter points when it was fixed at 1556 ; 1444 + 1556 =
3000.
Table III, containing nearly 5000 ratios, calculated to 6 places of decimals, is given in a pamphlet
which accompanies the instrument.
Opposite 24 and under 6, or answering to 246, we find 089324, showing that 246 is to 8000 less 246,
or to 2754, as 089324 : 1.
A vernier that subdivides a line into 10ths may also be made to read 20ths, by making the spaces on
the vernier coincide with those on the line; or rather, by making two consecutive divisions on the
vernier fall just inside of two consecutive divisions on the line. For example-suppose that 0 on the
vernier has passed over 140 and 7 of the smaller divisions, and a little more, so that the space between
5 and 6 on the vernier falls opposite a space on the line, then the centre is at 14751 or 14755. Hence
the length of the instrument is divided into 6000 equal parts, and Table III. will answer for 6000 as
well as 8000. For instance:
Opposite 1475, in the table, we find 967212
and 1476
968502
2) 1290 = diff.
645
967212
opposite 14755, in the table, should be 967857
The converse of this operation is simple.
Any number of degrees, minutes, &c., may be laid off by setting the vernier at the number corres-
ponding to that which is nearest to double the natural sine of half the given angle: the remainder of
the operation is the same as that just described, only the radius is taken instead of the diameter.
IV. Let it be required to lay off an angle of 37° 34''646, or 37° 34'
632.
88"76.
2)87° 34''646
Nat. sine of 18 47323 = 322072
2
644144
Opposite .643888, which is the nearest to 644144 in the table, we find 1175.
If the centre be fixed at 1175, or 1825 its supplement, and the radius 0 A
taken between the greater opening, then will the lesser opening be A B the
chord of 37° 34' 88"76 = 37° 34''646; that is, OA : AB 1-000000 644144
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BYRNEGRAPH.
205
an accuracy is thus attained in laying off angles never before arrived at, by a contrivance so simple.
Although a sextant, theodolite, and other complicated mathematical instruments give angular distances
with as much exactness as can be required, yet we were unable to transfer them to our constructions
with the same accuracy, for want of a simple instrument like the one which we are describing. It must,
at the same time, be admitted that it requires more time to lay off an angle with the proportional com-
passes than with the protractor; yet, where any thing like accuracy is required, the additional trouble is
more than compensated for. To lay down 'an angle with the proportional compasses that is small, or
not greater than 10 degrees, it is better to lay down an angle equal to 60° plus or minus the given one,
thus:
V. In the circumference of the circle ABB' it is required to lay off an arc equal to 8° 39'621 =
89' 37"26.
60° O'
8 39621
2)56 20379
Nat. sine of 28 10-1895 = 472088
2
944176
Opposite 944264 in the table we find 1457, the nearest to 944176; therefore if the centre be set at
1457, and o A, the radius, taken between the greater opening, the lesser opening will extend from A to
m, and the angle m o A 56° 20'379 and if the angle B'OA = 60°, the chord of which equal the
radius, then the angle B'O m equal 3° 39'621 = 3° 39' 87"26 hence B m is an arc subtending this
angle. Without changing the centre the same may be done with any other circle, whose radius can be
taken between the greater opening.
In this example, OA : A m : 1*000000 : 944176 or, which is the same proportion, o A: A m 1543 :
1457. By this simple means an angle may be laid down to the decimal of a second, and that, too,
with as much accuracy, be the circle large or small. 954176 falls between 943005 and 944264 in the
table. We have selected the number indicated by the latter, for although it is greater than 944176,
yet it is nearer to it than 943005.
The lines of surfaces or of squares, show the
633.
ratios between the areas of similar plane figures,
and like the other lines may have a double set of
divisions. The integral divisions marked 1, 2, 3,
4, &c. The fractional divisions are common to
the four lines; the numbering of this line is the
same as that of the line of lines, 10, 20, 30, 40,
B
c
D
dc., reckoning from the shorter points to the
longer. If zero be set to 2073 or 927, which is
found opposite 5, in Table IV., (see pamphlet,)
and the radius A B of any circle measured with the
greater opening, then if a circle be described with
CD the lesser opening, this circle will contain 1-5th the area of the other. The same may be said of
squares, triangles, or any other plane figures that are similar.
634.
3
VI. Let it be required to describe a figure abcde, similar
to ABCDE, whose area will be 17 of it, or, which is the
same,
Area ABCDE area a 37 17. = 677834,
c
which can be readily determined by logarithms, as follows
D
Log. 17
1.2304489
Log. 37
15682017
6622472
Log. 677834
18311236
Opposite 677852, which is the nearest to 677834 in Table III, we find 1212. Hence, if the move-
able centre be fixed at 1212 or at 1788, and the lines AB, AC, A D, &c., taken within the greater
opening, the lesser opening will give a b, ac, ad, &cm, to form the figure ab de similar to ABCDE,
whose area will be in the proportion required.
VII. On two maps of the same place, say America, the distance between New York and Baltimore
stands between the greater opening of the proportional compasses on one, while the distance between
the same places stands between the lesser opening on the other map; the centre is found to be at 1234:
required the number of times one of these maps is greater than the other.
8000
1766
2
1234
1766
1234
20481 times nearly.
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BYRNEGRAPH.
By logarithms.
Log. 1766
32469907
Log. 1234
30913152
1556755
2
3113510 = Log. of 20481.
The use of Table IV. is obvious, for if the zero be set at 1309 on the line of surfaces, lines similarly
placed in similar surfaces or figures will exactly fit between the openings of the instrument, when the
area of one of the surfaces or plane figures is 6-10ths of the other; if the zero be set at 2145, the open-
ings will coincide with lines similarly placed in similar figures when the area of one is 6 and 3-10ths
the area of the other; and again, if the centre be set at 2561, the openings of the points will coincide
with similar lines in similar figures, the area of one being 34 times the area of the other.
Line of Solids.-The arrangement of this line resembles the arrangement of the Line of Surfaces;
with this line similar solids are compared, by taking between the points of the instrument lines that
are similarly placed in them, in the same manner that similar surfaces were compared bv the line of
surfaces.
VIII. At what division on the line of solids must the vernier be set, so that if the side of a cube be
taken between one pair of points, the side of a cube 78 times as large will fit between the other pair of
points, with the same angle of opening!
: 1 = : 6
= 283714
By logarithms.
Log.
6
7781518
Log. 47
1-6720978
8)11060585
1.3686845 log. of 233714.
Opposite 568 we find 233552, the nearest number in Table I. to 238714; if the centre be clamped
at 568, then the cubes whose sides fall between each pair of points will be to one another as 47 : 6, or
the solidity of one of them will be 7g the solidity of the other.
IX. In two animals of the same species, which may be taken as similar solids, it was found that
the lengths of similar parts at the same time coincided between each pair of points, with the centre
fixed at 855 how many times larger is one of these similar solids than the other ?
From 3000
Take 855
= 15-79 times.
2145
By logarithms.
Log. 2145
33314273
Log.
855
2.9319661
3994612
3
1.1983836
So that one of these animals is nearly 16 times the size of the other.
Like the table for the line of surfaces, the use of this is at once apparent; for if zero be set at 1272
on the line for comparing solids, lines similarly placed in similar solids will exactly fit between the open-
ings of the instrument when the solidity of one of the bodies is 4-10ths (T4 or 4) of the solidity of the
other. If the zero be set at 1980, the openings will coincide with lines similarly placed in similar solids,
when the solidity of one is 733 times (7.3) that of the other. Again, if the centre be set at 2325, the
openings of the points will coincide with similar lines in similar bodies, the solidity of the one being 41
times the solidity of the other; that is, the solid between the longer points, or rather applied to the
longer points, will be 41 times the solidity of a similar solid similarly applied to the shorter points,
when zero on the vernier is set to 2325 on the line of solids; for in Tables IV. and V. the unit is sup-
posed to be placed between the shorter points.
X. Given a circle A BCD, to lay off a line equal to its circum-
635.
ference.
c
The diameter of a circle is to its circumference as 1 : 81416,
nearly opposite 3.1416 we find 2276 in Table III. to be the near-
est, but by proportion 3.1416 will be found to correspond more
A
nearly with 22757.
Set the index of the moveable centre to 7243, or to its supple-
E
M
ment 22757, then if any diameter A B be taken between the less-
er opening of the instrument, the greater opening will extend from E to F = the circumference of t]
circle A BCD; this will not be more or less than the circumference 100'000 part of the radius.
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BYRNEGRAPH.
207
XL Let it be required to construct a parallelogram, whose area
636.
shall be equal to that of a given circle BC.
B
As in the last example, set the index to 7243 or 22757 then take
the radius D A between the lesser opening, and it will be one of the
sides of the parallelogram E H; the opening of the other points will
C
be the other side EF, forming a parallelogram EG, equal in area to
D
the circle A B C.
XII. Let it be required to make a square equal in area to a given
circle A B.
H
G
When the side of a square equal 8862, and the diameter of a circle
equal 1; these areas are very nearly equal opposite 8862 in Table
III, we find by proportion 14095.
Set the index to 14095 or 15905, then 'if the diameter A B of the
circle be taken between the greater opening, the side DE of the
637.
square, equal in area to that of the circle, will be given by the lesser
opening; 80 that while the centre is thus fixed we can instantly make
A
squares equal to circles, or circles equal to squares, large or small, ac-
c
cording to the range of the instrument. It may be remarked, that
when the space on the vernier between 0 and 1 falls evenly between
B
one of the divisions on the limb, and the zero of the vernier beyond
to
1490, then the zero is said to stand between 1490 and 1491, or at
14905. This reading may require another example: Suppose the space on the vernier between 7 and
8 falls evenly between one of the divisions on the limb, and that the zero on the vernier is beyond 154,
then the zero of the vernier is said to stand half way between 1547 and 1548, or at 15475.
XIII Describe a circle whose circumference will be 111 inches. Set the index to 22757 or to 7243,
its supplement; then if the half of 111 inches, or 57 inches, be taken between the points of the greater
opening, the lesser opening will be the radius of a circle whose circumference will be 111 inches.
XIV. To divide an arc or angle of any number of degrees, minutes, &c., say of 84° 36'-25, into any
number of equal parts, say 3.
638.
It may be first necessary to make an angle of 84° 36'-25; this may be done as
before shown: 84° 36'-25 ÷ 2 = 42° 18'125 nat. sine of 42° 18'-125 = 673090,
and 673090 X 2 = 1-346180, opposite which, in Table III, we find 17215, to which,
if the index be set, and the radius taken between the lesser opening, the greater
B
will extend from A to C, and subtend an angle 00 = 84° 36'-25. Again, 84°
36'-25 ÷ 3 = 28° 12'083 ÷ 2 = 14° 6'047, nat. sine = 248630 X 2 = 487260, oppo-
site which, in Table III., we find 983, to which, or to its supplement 2017, the centre
must be set; then if the radius be taken between the greater opening, the lesser will
o
extend from A to B, and divide the angle CO A into three equal parts.
XV. Given the diameter of a globe A B to find the side
639.
640.
of a cube whose solidity will be equal to that of the globe.
When the diameter of a globe is 1; the side of a cube
equal in solidity to it is 805996, opposite which, in Table
III, 1338 is found, to which if the centre be set, and the
A
B
diameter of any globe A B taken between the greater
opening, the opening of the other points will give CD, the
c
D
side of a cube whose solidity is equal to that of the globe.
XVI. To describe a regular polygon, (e. g. hexagon,) whose
area will be equal to that of another regular figure, (decagon.)
The area of a decagon whose side is unity = 7694209 the area of a hexagon whose side is unity =
7694209
2.598076 then
= the side of a hexagon of equal area to a decagon whose side is unity
2.598076
this is readily found by logarithms to be 1-720902, opposite which, in Table III, we find 18975, to
which, if the index be set at any opening, one pair of points gives the side of a regular hexagon, whose
area is equal to that of a decagon, the side of which is found between the other pair of points, at the
same angle of opening.
641.
642.
F
With the index set
at 18975, A B will be
o
D
given by one pair of
k
points, while a b is
given by the other.
1
R
bl
XVII. In a certain construction the square root of 33 equal parts is required with great accuracy;
at what point must the centre be set to effect this object!
Opposite 5-74456 = 88 in Table III, we find 2555, to which, if the index be set, and any line
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208
CALENDER.
supposed to be divided into 33 equal parts taken between one of the openings of the compasses, the
other opening will give the square root of 33, and will not be in error 10000 part of a unit.
XVIII. It is required to lay off a line whose length is represented by the cube root of 7.
The cube root of 7 : 7 :: 1: 3.6593, or 7: 7 : : 1 : 3.6593.
Opposite to 3-6593, in Table III, we find 23565, to which if the index be set, the cube root of any
line supposed to be divided into 7 equal parts will be given in the lesser opening of the instrument,
when the line stands between the points of the greater opening.
CALENDER WITH FIVE ROLLERS, Designed and Constructed by Messrs. A. More and Son,
Glasgow. Fig. 644, an end view; Fig. 643, a side elevation; the same letters of reference denote the
same parts in each view.
A A A, three cylinders or rollers made of paper, the construction of which will be noticed afterwards.
BB, two cast-iron cylinders, made hollow to allow of the introduction of hot bolts of iron within them;
or of steam, when it is required or preferred.
644.
H
H
H
643.
D
D
G
D
E
<
B
I
B
C
C
C
A
A
C
F
F
SCALE.-1-4th inch = 1 foot.
645.
646.
C
G
D
ID
D
A
A
Q
0
A
0
C
c
B
B
F
SCALE.-1-5th inch = 1 foot.
00, the two side-frames or cheeks, into which are fitted the several brass bushes for the cylinders to
turn upon.
DD, top guides, into which the cross-head G, and elevating screws H H, work.
EE, top-pressure levers, connected by a strong rod of iron with the under-pressure lever F. This
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CALENDER.
209
system of levers is connected with the cross-head G, by two strong links of iron. The elevating screws
H H pass through the cross-head, and rest upon a strong cast-iron block, into which is fitted the brass
bush of the top paper roller. By means of the screws, the cross-head and levers can be raised or
depressed as required, and when the calender is working warm and requires to be stopped, the elevating
screws are screwed up for the purpose of lifting the paper rollers off the hot cylinders, to prevent their
being injured by the heat.
The construction of the paper rollers or cylinders is as follows: Upon each end of an arbor of malle-
able iron, of sufficient strength to withstand the necessary pressure without yielding, is fastened a
strong plate of cast-iron, of the same diameter as the roller to be made; the plate is secured in its
proper place by a ring of iron, cut in two, and let into a groove or check turned in the arbor. When
the roller is finished, the annular pieces are kept in their groove by a hot hoop put upon the outside
of them, and allowed to cool. A plate is fitted on the other end, of exactly the same size, and in the
same manner.
In building the rollers, one of the plates is taken off the arbor, but the other is allowed to remain in
its place. The paper sheets of which the rollers are to be made, have each a circular hole cut in the
centre of it, of exactly the same diameter as the arbor. The sheets are then put upon the arbor, and
pressed hard against the fixed plate. When the arbor is filled with paper, it is put into a strong
hydraulic-press, and pressed together,-always adding more paper to make up the deficiency caused by
the compression, until the mass will press it no harder. The half rings are then put in their place, to
prevent the plate from being pressed back by the elasticity of the paper. The roller is now to be dried
sufficiently in a stove, the heat of which causes the paper to contract so as to be quite loose. The roller
is then again taken to the press, and the unfixed plate being removed, more paper is added, and the
whole again compressed, until the roller is hard enough for the purpose to which it is to be applied. It
is next turned truly in the lathe till it acquires a very smooth surface.
The wood-cut, Fig. 647, shows the manner in which the calender is geered to make it a glazing
calender. In this cut, a marks the top cylinder of the calender, upon which is keyed a spur-wheel b;
and c is the under cylinder, upon which is also keyed a spur-wheel d. The intermediate or carrier-
wheel e, when drawn into geer, reduces the speed of the under cylinder c, one-fourth. Now, the cylinder
a, being the one that gives motion to all the rollers, and revolving always at the same speed, the cloth
647.
648,
b
h
in its passage through all the rollers below the cylinder a, is carried through at a speed one-fourth less
than if it passed only below the cylinder a; consequently, when it comes into contact with a, it is
rubbed, and thereby glazed, in consequence of the cylinder a moving one-fourth quicker than the cloth,
as above stated.
The wood-cut, Fig. 648, shows the manner in which the rollers are lifted clear of each other when the
machine is stopped. In this, e.e are two rods of iron, attached to the block or seat of the top roller
bfg, three bridges of malleable iron, capable of sliding upon the rods ee; but held fast upon the rods
when once they are adjusted to their proper places by pinching screws. The bridge b is placed half an
inch clear of the bearing of the cylinder a, when all the rollers are resting upon each other; the bridge f
is placed one inch below the bearing of the paper roller h; and the bridge g is placed one inch and a
half below the bearing of the cylinder c. When the pressure screws of the calender are lifted, the
blocks of the top roller being attached to them, the rods ee are lifted also, and along with them the
different rollers as the bridges successively come into contact with their respective bearings.
The manner of passing the cloth through the calender varies very much, according to the amount of
finish required upon it. The various methods are accomplished by different arrangements of the
geering, so that a calender calculated to do all the different kinds of finishing becomes a very compli-
cated machine, on account of the quantity of geering required. For common finishing, the method of
passing the cloth through the calender is as follows :-The cloth is passed alternately over and under a
series of rails placed in front of the machine, so as to remove any creases that may be in it, and is then
introduced between the lower roller A and cylinder B; returns between the lower cylinder B and the
centre roller A; passes again between the central A and the upper B, and again returns between the
top pair A, B, where it is wound off on a small roller, (hid in the drawings by the framing of the
machine,) pressing against the surface of the top roller A. When this small roller is filled with cloth it
is removed, and its place supplied by another, to be in succession filled as the motion of the machine
progresses.
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CALENDER.
Water-Mangle with two copper, and three wooden rollers; designed and constructed by Messrs. A.
More and Son.-This machine, Figs. 645 and 646, differs nothing in principle, and little in general
construction, from the five-rollered calender above described, except in this-that it is intended
for wet goods. It is drawn to a scale slightly less, but the views given and the lettering of the parts
correspond to those of the preceding figures.
A A A, the three wooden rollers, and BB, the two copper rollers of the mangle. These last consist
of a copper cover upon a cast-iron body, through which passes a wrought-iron arbor, differing from those
of the wooden rollers in being round, whereas these are square between the bearings. The smaller of
the two copper rollers, namely, the third in order, is in this arrangement the driver, the mangle being
driven like the calender, by a system of reversing geer not shown in the drawings.
The pressure in the mangle is brought on by a system of levers, which differ slightly from that
described. In this, indeed, there are strictly two distinct pressures: that brought on the axis of the
middle roller by the lever E, which is connected by a link with the weighted lever F; and that
transmitted through the whole system of rollers by the single-weighted lever D. The weight of this
last is regulated by means of a set-screw, which turns in a nut in the jaws of the lever D, and bears
upon the set-block which rests upon the arbor of the top roller. This pressure is thus transmitted
downwards from the top roller throughout the whole set, and at the middle roller B is added to the
pressure obtained by the lever E. By this arrangement, the pressure between the three under rollers
is greater by the pressure of E, than it is between the upper pair; but, for very high pressure the lever
D may be locked by set-pins and the set-screws turned down by the hand-wheel G, until the requisite
degree of pressure is obtained.
The manner of passing the cloth through this machine is the same as that already described in the
calender, with this single exception, that before the cloth enters between the lowest roller A, and the
small cylinder B, jets of water from a pipe, perforated with small holes, extending the whole width of
the machine, are allowed to play upon the cloth, 80 as to impart to it sufficient moisture for causing it to
receive the requisite degree of smoothness preparatory to the starching process, and at the same time
allow the cylinder B to free it from any impurities that may be remaining in it, by forcing them back
with the expressed water.
CALEMBEG. See WOODS, varieties of.
CALENDER. Description. A, two cast-iron frames. BCD, three cylinders. EFG, thrce cog-
wheels. HI, two force-screws. KL, two fly-wheels with handles.
649.
1
E
The cylinder B, which is in cast-iron, and hollow, is heated by another iron cylinder heated red hot.
The material of the cylinder C is pasteboard, its axle is of wrought-iron. These three cylinders must
be perfectly round and parallel.
The wheel F forms the communication between E and G, which rest upon the cylinders B and D.
The relation of F to the circumference of the cylinders is such, that when the machine is set to work
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these cylinders slide, causing friction, and thus give a gloss to the cloth. The friction is variable, ac-
cording to the nature of the tissue.
650.
K
H
E
F
R
G
In order to set the machine in motion, the fly-wheels K and L being turned in order to press the
screws H and I against the pillows of the first cylinder B, the cloth is placed between the rollers in the
direction indicated by the arrows.
CALICO: Machine for printing in four colors. In this machine the pressure is normal, in all the
engraved rollers, by the means of the levers P. These rollers are turned by a belt communicating with
the prime mover. The regulators are adjusted by screws, to which are attached hands, indicating, upon
dials, the space to be run by the rollers in order to reach the regulators: this is known without stopping
the works.
The engraved rollers can be brought up to the pressing cylinder, or withdrawn from it, without
changing the places of the color-vessels or of the scrapers, for all the different pieces fixed against the
pillows on the turning pieces of the engraved rollers, move with these last. Finally, there is an appa-
ratus placed behind the under cloth, the intermediate cloth, and the stuff to be engraved, by which the
workman governs these three pieces at will.
The engraved rollers are sometimes made of copper, sometimes of brass, or of copper and tin. The
first are to be preferred, being less apt to be injured; with such a cylinder 30,000 pieces can be
printed with the most delicate patterns.
The brass cylinders will be injured in proportion to the acidity of the printing-mixture, the zinc being
attacked Those in whose composition tin is introduced are more hard, but also more difficult to en-
grave. Some of these cylinders are hollow, others are massive: either may be used.
The diameter of the cylinders varies from 0.23 to 0.82 feet, according to the option of the manufac-
turer, and also to the dimensions of the pattern.
The dimensions of the pressing-rollers make no difference in the impression : the lesser ones should, on
certain considerations, be preferred, for the engraved rollers always yield under the pressure of the first,
so that it becomes necessary to give a curve to the pressing-roller equal to that of the engraved ; and
as the pressure it exercises is inversely to the augmentation of its diameter, it becomes necessary to
increase the weight on the subterraneous levers, thus giving still more chance to the engraved cylinders
to bend.
M. Huguenin thinks that a pressing-roller having only a diameter of 0.856 feet, for machines printing
only one color, and that of those printing several colors, the smallest possible must be used. In some
manufactures these rollers are wrapped with a band of a tissue, the warp of which is flax, and the weft
of worsted, having the property of not lengthening under pressure; at the centre of the roller, this
envelope is 0.062 feet thick, at the extremities 0.032 feet. The most modern improvement in this respect
is the introduction of a tissue of cotton and caoutchouc.
The furnishing rollers have their circumference enveloped in a woollen cloth; their speed is inferior
to that of the engraved cylinders; their diameter is generally about 0.328 fect.
The vessels in which the rollers dip are made of copper or wood. It is necessary to keep them sup-
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CALICO MACHINE.
plied with a constant quantity of printing material, for the rollers would soon only skim over the sur-
face of the fluid and leave but a feeble impression; to this end a reservoir pours a continual supply. A
partition is placed in a position which enables it to clear the roller of the froth with which its surface
may be covered.
651.
R
a
T
S
S
G
B
H
D
H
H
H
D
H
G
G
N
M
L
0
D
K
P
P
a
P
A A, frame-work.
I, a shaft communicating with the
PPPP, levers which are loaded with
BBBB, pressing cylinder.
moving power.
weights in proportion with the
cccc, engraved cylinder.
KKKK, wheels adapted to the fe-
pressure required: they are situ-
DDDD, scrapers.
male screws LLLL, which put
ated beneath the floor.
EEEE, vessels containing the color-
the levers in communication with
Q, the cylinder round which the cloth
ing matter: they are raised and
the pillows of the rollers.
to be printed is rolled.
lowered at pleasure, by the screws
M, a wheel communicating with the
R, the cylinder round which the in-
FFFF.
driving power, whose office is to
termediate cloth is wound.
GGGG, endless screw, guiding the
press the rollers; it also moves the
S, a weight which keeps the cloth
regulators.
wheel N, and the endless screws
stretched on the cylinders QR.
HHHH, pinions and wheels which
0000, which are engaged with
T, a roller used to give an inclination
turn all the machinery.
the wheels KKKK.
to the cloth when printed, and reg
ulate the speed.
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CANDLES.
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CAMWOOD. See WOODS, varieties of.
CANARY-WOOD. See WOODS, varieties of.
CANGICA WOOD. See WOODS, varieties of.
CANDLES, Wax. Next to tallow, the substance most employed in the manufacture of candles is
wax. Wax candles are made either by the hand or with a ladle. In the former case, the wax being
kept soft in hot water, is applied bit by bit to the wick, which is hung from a hook in the wall in the
latter, the wicks are hung round an iron circle, placed immediately over a large copper-tinned basin
full of melted wax, which is poured upon their tops, one after another, by means of a large ladle.
When the candles have, by either process, acquired the proper size, they are taken from the hooks,
and rolled upon a table, usually of walnut-tree, with a long square instrument of box, smooth at
the bottom.
CANDLES, Stearic-Manufacture of. Among the tallows which are best adapted for the prepara-
tion of stearic candles, are those of beef and mutton All other fatty matter is poor in solid acid,
or of too considerable a price. It is, then, the quantity of acid, stearic or margaric, which is found in a
given weight of beef or mutton, and the facility in working the same, which ought to determine in
giving preference to this or that quality of tallow. The mutton tallow contains the greater quantity of
solid acid, and is the more easily worked. That of beef is, generally speaking, to be procured a little
cheaper.
The manufacturers of stearic candles, to free themselves from the inconvenience of melting, are gen-
erally in the habit of buying from the butchers fat already melted. This method is far from being
the best, as it is almost impossible to judge the purity of the tallow when it has been melted, and at
the same time gives an opening for imposition to a considerable extent. Thus it would be most im-
portant to the manufacturer to purchase the tallow in lumps, in such manner as it is taken from the
animal, covered with its membranes, and bound in its cellular tissue, and to melt it himself.
This operation of melting is performed in the slaughter-houses of Paris in a very simple manner.
They have a great copper, from 6.56 feet to 7.21 feet diameter, and from 3.28 feet to 3.93 feet in
depth, swelling at the bottom as in a stewpan, and widening at the top, so as to be enabled to rest
upon a circular oven. This is constructed in such manner that the hearth, of a breadth of 1.32 feet, is
exactly under the copper, from its circumference to its centre. The flame and hot air heat at first the
whole of the bottom surface, and then circulate twice round the cylindrical part of the copper before
passing up the chimney. They throw the fat in this copper by an inclined plane, which proceeds from
the upper story, and during the melting they stir it with a long rod. When they have reached a
proper degree of fusion, which is generally obtained in about four or six hours, according to the nature
of the fat, they turn it out, first into a large iron-plate reservoir, of the same size as the copper, and
which is furnished with two cocks, from which it is drawn off into slightly conical vessels, SO as to form
large lumps of a conical shape.
It is well to place under the copper a large funnel, the same as in a forge, to conduct the gas which
escapes from the fat during the operation to the chimney. There should be also in the same fac-
tory a screw-press, for compressing the membranous part, in order that no portion of fat may be
lost.
The different operations in general use for the manufacture of such candles are generally divided as
follows:
1st. The formation of soap; the object of which is to combine the acidulated fat with the lime, to
produce the glycerine, and obtain the stearate, margarate, and oleate of lime. The glycerine dissolves
itself in the water necessary for this preparation.
2d. The pulverizing of the lime soaps.
3d. The decomposition of these same soaps by sulphuric acid diluted with water.
4th. The cleansing of these stearic, margaric, and oleic acids-first, by water slightly acidulated, and
secondly, by pure water.
5th. The moulding and crystallization of the now obtained acid fats.
6th. The melting of the crystalline masses into small layers instead of large rolls.
7th. The cold-pressure of the acids thus formed into layers.
8th. The hot-pressure of these layers now reduced.
9th. The purification of the solid acids by water slightly acidulated at first, and secondly by pure
water.
10th. The melting and moulding of the solid acids into moulds; then the clipping of the candles.
11th. The bleaching of the candles.
12th. The polishing, packing, &cm for removal.
Description of the Machinery.-Fig. 652 represents the general plan of a manufactory, indicating the
utensils which are employed.
Fig. 653 is a sectional view of this manufactory, vertically and longitudinally; and the figures 654,
655, 656, and 657, represent in elevation, or sectionally, the details of the principal utensils, and the
means of communicating the movement.
The Formation of Soap.-This operation is performed in a large vat, generally constructed of wood,
slightly conical in form, and provided with several frets all the way up. The bottom and the lid are
of wood, and its capacity is sufficiently great to contain, easily, more than 7058 cubic feet. They gen-
erally place about 1100 lbs. of tallow, with a proportion of water rather more than enough to easily
dissolve the same, and which would be about 200 gallons. This is heated by steam from a leaden
pipe g, winding in a serpentine manner, and placed at the bottom of this trough. This pipe is per-
forated with a number of small holes, across which the steam passes as it proceeds from the coppers
A or A', with which it is in communication. When this is melted, they add, by degrees, 165 lbs. of
lime well mixed; and they allow this preparation time to mingle, taking, at the same time, great care
to stir it by means of an agitator p, composed of many branches united by a cross-piece, and having a
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CANDLES.
kind of knife fixed at each of the four arms. This contrivance is mounted upon a vertical beam o,
to which is given a rotary movement by the wheel n fixed to the upper part of the beam.
This wheel is acted upon by a pinion n' adjusted upon the horizontal beam, which communicates with
the prime mover by the two pair of cog-wheels 11' and jj, mounted on one part upon the vertical beam
k, and on the other part upon the horizontal beam F, as seen in Figs. 652 and 653. An energetic stir-
ring is most important, because it more fully completes the formation of soap, and economizes, conse-
quently, the sulphuric acid.
Generally, in the greater part of the manufactories, says Mons. Dumas, they use, perhaps, 33 lbs.,
and sometimes more, of sulphuric acid, to the 220 lbs. of tallow, while they ought only to use from 19
to 22 lbs. to 220 lbs. of tallow. It is often, then, a third too much, and an experienced manufacturer
would do well to pay attention to this.
They had proposed to give the movement to this agitator by means of a cord, but they found they
were obliged to give up this, as they could not obtain a regular movement-during one part of the
operation the matter, being very compact, would present a great resistance, and the rope would give.
The time for the formation of soap is generally from 6 to 8 hours. At the end of this period they
draw off, by means of a tap q' placed in the bottom of the trough, the liquid part which has absorbed
the glycerine, and they take from the trough all the solid which remains there, which is now a forma-
tion of stearate, margarate, and oleate of lime, in the form of a very hard soap; this they throw upon
the floor, upon which rests the trough J.
Pulverizing.-To pulverize the soap, they use, in many manufactories, a roller of cast-iron K, which
they pass to and fro in an alternate movement, and generally by manual labor. Mons. Dumas proposes
to have the soap pass between two cylinders moistened by a stream of cold water, which should bathe
it; a precaution most indispensable, because the soap, heated by the pressure, would soften, and render
itself more often in cakes than in powder.
Troughs for Decomposition.-The two troughs J1 and Jª, into which is conveyed the solid matter after
it has been broken, are designed for the decomposition of these matters by the action of sulphuric acid
much diluted with water. Like the former, in shape they are slightly conical, and nearly of the same
dimensions, heated by steam by a serpentine pipe q'. They ought, also, as with the former troughs
for the formation of soap, to be cased with lead, so as to be protected from the action of the sulphuric
acid. It would be quite as well to fit up both with a mechanical agitator, though in many manufac-
tories they are not SO. These troughs are generally on a lower floor, under the trough for the forma-
tion of soap, so that they can easily dispose of the matter.
The quantity of sulphuric acid necessary for the decomposition of these lime soaps can be easily de-
termined. For 1100 lbs. of tallow, according to Mons. Dumas, they would use 165 lbs. of lime; or for
220 lbs. of lime the equivalent in sulphuric acid is equal to 367 lbs., at 66° centigrade. Consequently,
for 165 lbs. of lime will be necessary 275 lbs. of this acid. In practice they add from 10 to 15 per
cent. to this quantity, and the acid being, we suppose, at 66°, they dilute it by twenty times its quan-
tity of water. At the end of about three hours the decomposition of these soaps is effected. They
then displace the mass. The fat acid comes to the surface, and the sulphate of lime is precipitated to
the bottom.
Cleansing the Acids.-For this purpose they withdraw, by means of a tap q', which is placed un-
derneath, and which, like the preceding ones, is cased in lead, and equally heated by steam by a ser-
pentine pipe placed in the bottom. It is as well to have a second trough L, similar to the preceding
one, to complete the cleansing, in which they work only with pure water. The passages R, inserted in
the interior of the roof, serve to establish a communication with the two troughs of decomposition J J',
and with those of cleansing L', and to carry the liquid off or into the lower reservoirs. As much as
possible of sulphuric acid and lime are drawn off into a series of zinc moulds M, which are arranged
in rows along the entire length of the workshop, in such manner, that in drawing it off into the first
mould it flows gently into the adjoining moulds, which is easily done by attaching to each brim of the
moulds a gutter, which carries off the superfluous matter at its proper height.
These moulds present the form of a rectangular prism from 27 to 39 inches in length, from 61 to 7
inches in breadth, and about 161 feet only in height. Thus are formed layers of solidified acid, which
are taken away (after being wrapped in woollen serge) to the vertical hydraulic press N, which is con-
structed exactly similar to the ordinary presses, of which it is easy to see the construction by reference
to the design, Fig. 653, where it is shown in vertical section.
The drawing off into these moulds, such as we have endeavored to show, is only a modern application.
Previously the acids were drawn off into larger moulds, which could contain about 7 gallons, and which
were a little wider at the top, so that the matter could be the more easily extracted. These rolls were
broken into smaller pieces by the action of a knife with an alternate movement, similar to a knife for
cutting straw into small parts. Since the use of these newly-invented moulds, they economize nearly
one-horse power in the impelling force.
Cold Pressure.-The vertical hydraulic press ought to be constructed to obtain a pressure of
440,000 lbs. A great part of the oleic acid flows cool to the action of this press, but, however, the lat-
ter portions can only be extracted by the aid of a certain temperature. Other presses of horizontal
construction, and which are heated by steam, are employed. Such is the press represented in PP,
upon the plan, Fig. 652, and upon the vertical section, Fig. 653.
Hot Pressure.-This press is heated; also the wrought-iron plates P', between which are placed
the links which proceed from the vertical press, and which, in issuing from this press, are enveloped in
horse-hair material, in place of woollen serge.
On the opposite side to the piston of the press is a cast-iron rectangular chest Pª, airtight, in which
is enclosed a similar action of plates. The steam proceeding from the generators A or A', passes by
the pipes e, e¹, e², t, finds its way into the double sides, as also into the double bottom of the press, to
heat it. It afterwards passes by the pipes t', which carry it into the chest Pª, where there is a full
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652.
in
S
8
:
.a
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=
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or
to
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CANDLES.
action of plates Pª to be employed as soon as the press will have ceased to work, and where they may
take away those that they have used. They can still heat these plates by boiling water in a trough,
also in cast-iron. It is shown by Fig. 653 in what manner these plates can be raised to furnish heat to
the press, or reciprocally.
They have provided for this purpose, in the upper part of each of them, an eye, which permits the
introduction of a hook fixed to the extremity of the cord u, which passes into a throat of cast-iron to the
pulley. The upper part of the locket of this pulley ends with an elongated eye, to enable it to glide
easily the entire length of an iron way fixed to the plank, and below the press, lengthwise-so that
one of the plates being raised, they can advance the locket in a perpendicular line. They can transport
them in succession either from the press to the chest, (which serves as a heater,) or from the chest to
the press.
The pressure of the piston of the press often ranges from 880,000 lbs. to 1,100,000. Some, after a
certain time of working, have had the bottom of the cylinder carried away by the pressure; and, in cer-
tain factories, others have been destroyed by the rupture of the long braces, which connect the heads of
these presses, and which were not sufficiently strong in themselves.
The oleic acid which flows from the vertical press, or from the horizontal one, into a lower receptacle
O, by the pipes S' Sª, from which it is drawn for the receiver into the flat vessels, by the cooling, de-
posites the stearic acid that it had absorbed in consequence of the increased temperature which it
underwent during the action of the horizontal press.
The two pressures completed, the oleic acid is regarded as sufficiently separated, and the residual
matter, formed by the stearic and margaric acids, is of brilliant whiteness; they only equal about 45 to
50 per cent. of the tallow employed.
The injecting-pumps are shown by H and H, Figs. 652 and 653, which clear the two horizontal and
vertical presses. They are put into action by the horizontal beam F, which communicates with the
impelling power, which is an engine of about 4-horse power-a power more than sufficient to put in
motion the necessary apparatus of this manufactory.
Upon the horizontal beam E is a cast-iron upright wheel f, which commands the wheel f1, fixed upon
the horizontal beam g. This has, at its extremity, two small winches, which, by the accession of two
rods h, impart to the pistons of the injection-pumps il the movement for casting the water that they
draw into the great bodies of the presses N, P. The heads of the vertical press are supported at a
convenient distance by four cast-iron columns, interlaced by large iron bolts all the way up, and the
liquid matter falls upon the lower plate, which unites with the piston, and upon which they have
adjusted a small trench or gutter, to allow it to flow by the pipe s¹, finished in its upper part in form
of a funnel, and which conducts it into the reservoir O.
Purification of the Solid Acids.-The lumps of stearic and margaric acids which are taken from the
horizontal press, are carried to the trough R, to be there purified by dilute sulphuric acid.
This trough is constructed exactly similar to the preceding-cased in lead, and heated by steam, by
the pipe q3, which conducts the same in the serpentine q, which liquefies the acids. It must be under-
stood that this cleansing has for its object to disengage the fat acids from the remotest trace of lime
that they may contain. After this operation, it only remains to free them also from the acid itself, by
purifying with water. They then allow this to remain, or decant it into another trough R¹, situated upon
a lower floor, and which only contains pure water, and which should be occasionally replenished.
They then allow it to cool, draw it off into moulds, and at length is obtained rolls perfectly fit for work-
ing into candles.
Melting and Moulding the White Solid Acids.-They use for this purpose a copper, T, (see Figs.
652, 654, 655,) which are in the interior silver-plated, to prevent the discoloration of the acids. This
copper is double-bottomed, to be heated by steam at a temperature which should not ordinarily
exceed 100 degrees.
The steam proceeds from the generators into the double bottom by the pipe v, and this, condensed,
flows off by a pipe v¹. A tap v³, attached to the pipe which issues from the bottom of the copper,
serves to empty it completely. It is surrounded by a coat of wooden staves U, to prevent the cooling
of the trough. By the side of this copper they have placed a table V, upon which rests the vessel T,
which serves to receive the melted matter to be carried into the moulds.
In order to make the candles and the stalactites which form upon them less powdery, they generally
add 10 per cent. of sulphuric acid, when they throw in this copper the rolls of stearine. They cool
these candles in moulds similar to those represented in plar. and in section, Figs. 658 and 659. These
moulds are formed of an alloy, composed of one-third pewter and two-thirds lead. It will be perceived
that they are slightly conical, and terminated by a kind of funnel.
They fix the wick to the upper part by a bent pin y', and to the lower by a little wooden peg y,
which closes against the sides of the orifice. These wicks are matted, which prevents the necessity of
constantly snuffing the candles; for this purpose, says Mons. Dumas, it will be necessary to dip them
in a solution of borax, which forms with the lime a borate which fixes itself in the wick, and serves to
consume it.
To fix the wicks, the moulds are placed vertically in the holes of the wooden tables S, conveniently
arranged in the workshop, and upon which they allow the candles to cool, after they are drawn off.
For this purpose, after the wicks are fixed in the centre of the moulds, they carry them to the hot-
water basins, which are brought up to the temperature of boiling water.
This system of heating is brought about by several basins V, represented in plan and section, (see
Figa 656, 657, and 652.) They are entirely surrounded by water, heated by a current of steam com-
ing from the generators by the pipe x in the serpentine x¹, placed in the bottom of the apparatus.
When the moulds are sufficiently hot, they are filled by the aid of a small vessel T1, which they
plunge in the copper T. It should be first ascertained that the acid has commenced to crystallize.
This precaution, as much as that of heating the moulds, is very essential to neutralize the crystalli-
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655.
654.
di
at
a
5
657.
656.
of
9
659.
658.
x
N
10
4
to
8
Fig. 653: SCALE.-5 33 inches=33 feet. Figa. 654 to 659: SCALE.-8 inches= 13 feet.
II
:
J
J
653.
M
K
M
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CANDLES.
zation of the fat acids-a crystallization which would give to the candles a very disagreeable appear-
ance.
After the cooling of the moulds, they remove the small wooden peg which holds the wick, and by
means of a punch, they extract the candle. The roll must also be cut, and the candles be put length-
wise. For this purpose many mechanical means have been tried, and which have not produced very
satisfactory results; the difficulty to avoid breaking the candle being so great. However, they are at
this moment trying the effect of a certain mechanical knife or circular saw, from which much is
expected. For this process we believe it is most important that the cutting-blade should possess great
rapidity and very little pressure.
Bleaching the Candles.-When the candles are moulded, they should be exposed for some time to
the air, to the light, and to a humid atmosphere, that they may possess as white an appearance as
possible. This is generally done upon the roof of the workshop itself, which should be constructed in
the form of a terrace, where the candles z can be arranged upon the trays Y. Space should be econo-
mized as much as possible.
Polishing the Candles.-The last two processes which the candles have to undergo, after they have
been exposed to the air some time, are the polishing and the packing. The polishing is done by rub-
bing the candle briskly with a piece of cloth, damped with alcohol or ammonia; and this is generally
done by women or children. They have also tried to produce the polish by a mechanical process,
having a kind of cylindrical plug or bung of wool or cloth, to which was imparted a regular to-and-fro
movement, whilst the candles were immediately placed under the same, and by the means of endless
chains, which advanced gradually upon a horizontal table, the candles rested and turned equally at the
same time. This process is the invention of a Mons. Davison, of Paris, who has taken a patent out for
it for five years. The packing consists in arranging them to form packets of one pound, and they are
carefully and neatly secured ready for use.
Boilers, or Steam-coppers of the Machine.-The two boilers A and A', represented in Fig. 652,
are for the purpose of feeding not only the engine, (of 4-horse power,) but also for heating the dif-
ferent troughs; for the formation of soap; for decomposition and cleansing the horizontal press; the
copper for melting, and the warmer. These boilers are of 16-horse power. There are some factories
which have them as large as 20-horse power. Fig. 652 represents a horizontal projection seen from
the top, and shows the disposition of these boilers, with their safety-valves, and also the pipes for
conducting steam. In B will be perceived the brick furnace, in which the boilers are imbedded; in
b the safety-valves; and in b' the floats c shows the pipe communications with alimentary pump; e' e'
the pipes for conducting the steam to the different apparatus of the machine; and d d' the pipes which
furnish the steam-engine. All these pipes are of copper, and provided with taps.
Application of the Oleic Acid-This acid, for a long time in the different factories for the manufac-
ture of stearic candles, was regarded as a superfluous residue, and you may say completely lost, with
respect to any advantage that could be derived from it. Messrs. Pelicot & Alcan have been success-
ful in applying it to the purpose of greasing the wool employed in silk-yarn manufactories, or in scour-
ing it.
It is well known, in the picking or combing of wool, that a nap as homogeneous as possible is neces-
sary. It is first prepared with a certain quantity of fat matter. This preparation is so far necessary,
that without it the twisting and stretching of the wool would only be accomplished indifferently, and
the loss would be greater. The thread thus obtained would be more unequal, and would not possess,
for weaving, the quality required for the production of stuffs. Until within the last few years they
have employed, for this purpose, vegetable oils, in most of the principal factories at Rheims, Sedan,
Elbeuf, &c. In the factories of the south, olive oil was almost always used, whilst in the suburbs of
Paris they have given the preference to the oil from grains, which was cheaper, and in some cases a
mixture of water and oil is used, brought to a state of emulsion by the addition of a small quantity of
potass.
The oil with which wool is impregnated should only remain until immediately after the spinning or
weaving. Scouring should commence at that period. The process of scouring varies with the nature
of the stuff they propose to manufacture. For cloths and felt stuffs it is done after the weaving, and be-
fore fulling. For light and rasé stuffs it is generally done upon the thread, and before the weaving.
At Elbeuf, Louviers, and other places, scouring is accomplished by means of potters' clay saturated
with water. The thread being impregnated with this substance, they pass it between two compressing
cylinders, which brings it in contact with the greasy matter; this is consequently displaced, mechan-
ically, and is drawn off by the water, which flows in great quantities. This process will take from
eight to twelve hours, and it will affect the soundness and color of the tissue; besides, the accidental
presence of any small stone in the clay will occasion a rent or imperfection in the same. It is also very
uncertain; and if in the first process there is a failure, it becomes more difficult again in the second, in
consequence of the deposite of insoluble salts, arising from the application of water. An imperfect
scouring prevents the stuff receiving the color as effectively as it should.
The oil which has been used for the greasing becomes entirely unfit for any other purpose; for, on
reference to experienced men upon the subject, the result is nearly as follows: 88 lbs. of woollen cloth
will imbibe 18 lbs. of oil, and they are diluted by 2843 gallons of water.
In the south, where they manufacture large quantities of common cloth for troops, or for exportation,
the vegetable is not always entirely lost in the scouring. To extract this, they employ water mixed
with soap and alkali: this is absorbed by heat, and then employed in the fulling of the stuff already
scoured. This scouring, although very imperfect, still is, however, more economical than the former.
In Sedan, for the manufacture of black cloths, &c., the greasing and the fulling are generally done at
the same time. For this purpose they use a solution of soap or urine, and sometimes a combination of
both. When they wish to scour the wool in thread, they use soap solution sufficiently powerful.
Messrs. Peligot and Alcan, to remove many of the inconveniences attending these processes, thought
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to remedy them by the use of the acid stearic, instead of the vegetable oils. We have seen that
the tallow formed into soap is transformed into two fat acids, the one solid and the other liquid. The
first is the acid stearic for the manufacture of candles, and the second is the acid oleic. This last, until
within the last three years, was not employed for any special purpose. These chemists, in applying it
to the woollen factory, have not only rendered a great service to this last, but also to the manufacturer
of stearic candles, in augmenting the value of a portion of their residue.
The employment of the acid oleic, besides economizing the actual price of purchase upon that of
olive oil, or that from grain, offers this very important advantage-that it is immediately soluble in the
carbonate of potash, with which it combines in the formation of soap. The scouring becomes a chemi-
cal process-for it consists in immerging the stuff for some instants in an alkaline water, and then
washing it in an ordinary apparatus.
The scouring of the threads by this process has a still greater advantage, because it can be effected
simply by an alkaline solution, instead of the more costly employment of a considerable quantity of
soap, and equally in employing the fresh residues as in former ones.
This process is again very economical, as it furnishes itself the soap to be employed in the fulling,
an operation which generally follows the scouring. The oleic acid having the direct property of a
true soap, by its combination with carbonate of potash, a property that none of the vegetable oils pos-
sess in any degree or shape whatsoever, (and of which an exclusive use was made,) they now obtain,
as a consequent residue from the scouring, a liquid combining the properties of soap and alkali, which
before they had to provide for the fulling of the stuffs.
Besides the waste in picking, of little moment when they employ the ordinary oils, this is completely
saved by the facility of scouring offered by the use of the acid oleic.
From numberless experiments it is proved, that the wool greased by the acid oleic does not become
heated, neither does it ignite even when placed in circumstances most favorable for combustion.
The acid oleic, such as is left by many factories of candles, could not be employed for the purpose of
greasing wool until it has undergone a complete purification, or been brought into a homogeneous sub-
stance possessing all the above-mentioned characteristics. That which they employ at this time in the
cloth factories can only be compared, by its clearness and color, to the finest olive oil employed in the
same factories.
In certain factories of the stearic candles they manufacture with the acid oleic a hard soap, which is
sold to the dealers in large lumps.
Apparatus necessary for the manufacture of Stearic Candles.-Horizontal press, or hot press, as rep-
resented in Fig. 653, including injecting-pump.
Vertical, or cold press, with iron columns and injecting-pump.
Cast-iron chest, as in Fig. 655, for the heating of the plates.
Each plate weighs about 100 lbs. cast-iron.
The troughs (deal) for cleansing and decomposing, with the iron frets which surround them.
The pipes and lead casing-the agitators and their movement.
Steam-engine, high-pressure, 4-horse power.
Two boilers, each from 16 to 18 horse power. Also many other indispensable accessories, such as
moulds, heaters, transmitters of movements, and pipes.
CANNONS OR GREAT GUNS; the machinery for the boring of. The manufacture of cannons is
divided into two branches, the founding and the boring. Here we only treat of the latter branch, and
restrict ourselves, concerning the founding, to the remark, that formerly the cannons were founded over
the core, (as it is called,) or with the bore, which then was perfectly regulated by means of the borer;
while at present they are generally founded massive, and afterwards bored in boring-mills.
These boring-mills work either vertically or horizontally. The former were exclusively used until the
middle of the last century; the boring consisted only in the enlargement of the founded bore conforma-
ble to the calibre, and the opinion prevailed that brass cannons could be bored in no other manner than
this. But since then the advantages of the horizontally-working boring-mills have become 80 apparent,
that but few of those working vertically are still extant. A short description of the three principal
systems of the latter will therefore be sufficient here.
In the machines constructed according to the oldest and most imperfect system, the cannon rests
vertically, and with the grape upwards, in a wooden sledge which runs in the furrows of two side-
beams, and can be moved up and down by means of long tackles. Beneath the cannon, and in the
direction of its axis, is the borer running in a steel pan and crossed by a beam, by means of which it is
turned round by horses. The pressure required while boring, is effected by the weight of the sledge
and cannon, and can be regulated by counterbalances. But as the borer is to have some scope, the
borer can easily be brought out of its vertical position, and thus the boring assume a false direction
without its being noticed instantly.
According to the second system, the cannon rests with its muzzle-face on rollers, while its grape is
inserted into the shaft of a dented wheel connected with a moving power, and thus the cannon is turned
round its axis. The vertically standing borer is fastened at a aledge, which runs in the furrows of two
beams, and can be pressed onwards against the cannon during the operation of the boring, by a lever
drawn upwards by a string provided with weight-stones, and passing over a pulley. Both the exact
direction of the borer and its uniform pressure against the cannon is hard to be effected yet the ad-
vantage is here, that a false direction of the borer can instantly be noticed by the trembling motion of
the cannon and borer.
The third and best system of boring-mills working vertically, is represented by Figs. 660 and 661, in
front view, and section through the axis of the cannon and boring-bar. Here the borer is fixed, while
the cannon turns round its axis, and moves up and down in a sledge, and by its weight the required
constant pressure against the borer is effected. The square piece of the cannon's grape is clamped into
the maif marked with T, and which at the same time takes up the lower square part of the boring-
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spindle S. The latter is, together with the cannon, turned round their common axis by a motive power
between the fixed rails C₁ and C2, by means of the cog-wheel U, the spring-wheel V, and a cog-wheel
at the vertical shaft W. The boring-spindle is provided with a bell-shaped runner of brass, whose feet
turn on a steel plate inserted into the rail G. In order to secure the position of the boring-spindle, the
latter has at its upper end an indentation for receiving the steel point of the bolt F. The cannon is kept
in a vertical direction by the slides of the rails E1 and En provided with adjusting screws. The hitherto
described contrivance moves, with the exception of the moving power between the side-beams A, right
up and down, the directing-beams I, together with the rails F, G, E1 and E, forming a sledge, which by
means of the drawing-machines N, the disks L, their shaft F, and the long tackles fastened to the upper
bolt B, can be lifted or lowered at pleasure. Fig. 664 shows the rail E1 in the upper view, and illus-
trates the working of the directing and running beams one into the other, and at the same time the
fastening of the rails to the directing-beams. The boring-bar is fixed in the sill D, and is kept in its
vertical position by the rails C, and C4 The upper rail C, is taken off, as soon as the cannon sinks
down into its vicinity. The drawing-machine is, during the boring, slackened, so as to allow the weight
of the cannon to act freely. With larger calibres, counterbalances may be applied to decrease the
pressure.
The first horizontally working machine was constructed in 1744 at Strasburg, by Maritz, inspector-
general of the foundries in France; and since these were constructed, other machines on the same
principle in Spain, Sweden, and England. The boring-mill at Chaillot, in France, is the first where the
power of stean. was applied; and that of Liege, in Belgium, is the most extensive, comprising twelve
horizontal boring-benches put in motion by four steam-engines. In both, the system is that of the can-
non turning round its axis, while the borer presses straight onwards against it. Another system pre-
vails in English boring-mills, according to which the borer is not only pressing against the cannon, but
at the same time rotating in a direction opposed to that of the cannon. Machines constructed on this
system are called cylindrical boring-machines. A third system unites with the contrivance for the
movement of the boring-sledge a uniformly advancing support for turning off the cannon.
We shall first describe the machinery according to the above-mentioned system, applied in the boring-
mills of Chaillot and Liege.
Figa. 669 to 677 represent a boring-bench and its single parts. In the mill of Liege three of such
benches are placed by the side of each other, and are put in motion by a steam-engine, which is directly
connected with the shaft of the middle boring-bench, while the dented wheels B are acting upon those
of the side-benches. If two boring-benches be placed at the end of each other, BO as to have one
common axis, they form what is called a boring-road that is connected with the prime mover in the way
of running boring-machines, which shall be described below.
Each bench, Figs. 669 and 670, consists of two long beams joined by cross-beams. The first two
cross-beams bear the sockets A and C of the axis, the next following two bear the saddles for the grape
and the mouth of the cannon, and the fifth and sixth serve as supports for the dented bar of the boring-
sledge, so that the beams can be placed and kept exactly in the same level the timber must be com-
pletely dry. The cross-beams are firm with the exception of the fourth one, which by double springs
moves in the furrows of the side-beams, as the different length of the cannons requires a corresponding
position of the saddle for the mouth.
For connecting the cannon with the axis, the square adjoined piece of the grape is to be put, together
with the square of the axis, in the muff D, which is fastened by small metallic wedges, driven in at both
sides. The cannon rests horizontally in two collars E and F, which in Figs. 673 and 676 are represented
in double scale. The socket of the grape E supports the latter only on the lower side, and can be
moved forwards and backwards on the beam. The socket F of the mouth embraces the cannon entirely
near its head-moulding, and allows it no other movement than the rotation round its axis. The con-
struction of these sockets (which are to be provided with copper standard-disks a, conformable to the
calibre) may easily be comprehended by the figures. The iron boring-bar a, (Fig. 670,) is put with its
back-squared end through the bow G of the carriage-frame, and held fast by a peg. The dented bar
H is fastened in similar way to the carriage, being put through the bow b to G, and held fast by a fore-
lock-bolt. The carriage-frame (Fig. 674) is made of cast-iron, and is moved by means of four wheels, run-
ning on the rails c of the long beams. The carriage must be of such weight, that it is not subjected to
vacillation; while the boring-bars are made as light as possible, yet at the same time strong enough to
prevent them from bending.
The means for the movement of the boring-sledge are very various. In the first boring-mills working
horizontally a dented bar was applied, put in motion by an endless screw or winch; then by means of
chains passing over rollers, and moved by a lever and weight-stones; and by a screw-spindle, whose
box was fixed in a wheel. Yet all these means of movement require either an experienced operative,
or they do not produce a uniform pressure. For this reason the manner of movement represented in the
delineation was applied in the boring-mills of Chaillot and Liege. It consists of a dented bar F, moved
onwards by the moving power I, at the axis of the dented wheel R, and by the action of the lever K,
charged with weight-stones. The lever K is at both ends provided with the segments N and o, in
whose grooves the string of the weight-stone P (which brings about the pressure) and the chain of the
iron hinge M are placed. The hinge (Fig. 677) consists of two parallel iron bars joined below by two
tenons, which latter stand asunder at equal distance, as two cogs of the obliquely dented wheel R do.
By this contrivance a uniform pressure of the borer against the cannon is brought on, but at the same
time it has the inconvenience of frequent shifting of the hinge. For this purpose, first the lever L is to
be laid in to prevent the retrogression of the dented wheel, and then the weight-stone P is to be drawn
up by means of the rope fixed at the segment 0, and passing over the roller Q to the axis T; a catch
V preventing the retrogression of this axis, turned by the moving power U. As soon as the hinge M is
shifted, and the catch V lifted, the weight-stone P begins its action again. In order to cause less inter-
ruption, in the most modern French boring-mills, the dented wheel is provided with a barrel, over which
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CANNONS.
passes a string with a weight-stone at its end. The string must also pass over a roller, which is to be
fixed as high as possible, to prevent a frequent hanging of the weights. It is well to provide the string
with rings, one foot asunder, so as to be enabled either to increase or decrease the pressure, by hang-
ing several weights one above the other. The movement of the boring-carriage must above all be uni-
form, without any start or pull. For this reason the screw-spindle is to be preferred to the dented bar
but the difficulty to make it exactly in these dimensions, and its expense, have prevented its general
application.
Fig. 675 represents the frame forming the socket for the moving power of the dented bar, and at the
same time holding in its lower part a roller with projecting edges, to facilitate the movement of the
dented bar, and to keep the latter in the direction of the cannon-axis, conjointly with the notch in the
back cross-beam.
A boring-bench arranged in this manner is adapted to great guns of every calibre however, in more
extensive boring-mills, there are several benches of inferior length for the boring of howitzers and
mortars.
The second system of the horizontally working machines is an imitation of the above-mentioned cylin-
drical boring machines. Two boring-benches at the side of each other are represented in Figs. 662, 663,
and 665, plan and side view. The prime mover being here either the power of steam, water, or animal
power, the toothed wheel of the principal axis m grasps the cog.wheels A of the two shafts n, which
belong to the boring-benches, and puts the whole boring contrivance in motion. Sometimes each of the
shafts n is arranged for two boring-benches, in which case the second ones are placed in the king-pieces
of the represented boring-benches, at the other side of the spring-wheels. The cast-iron sockets of these
shafts rest on a foundation X, made of square stones, and covered with plates of cast-iron. These plates
Y are firmly fixed to the foundation by screw-bolts, and are kept together at the edges by other bolts.
At each boring-bench in the socket-plates are two long and well-polished grooves p, for receiving the
screw-bolts of the cast-iron saddles and tressels T, U, V, W, Z, as well as the support for the turning
off. Along the grooves are cut out in the foundation, channels for the reception of the bolt-heads which
are wider than the grooves. By this contrivance the tressels can be moved'and adjusted by the screws.
The screw-bolts are altogether of the same dimensions, and can be taken out at proper places, which
enlargements of the grooves are to be closed by stops of iron. By taking down a tressel from the
boring-bench, the female screws need only be unscrewed, and the tressel to be lifted a little, to free it
from the bolt.
The socket of the shafts is formed of six iron posts, resting on a strong cast-iron plate, fixed by means
of screws. The two middle posts enclose the spring-wheel of the principal axis, while the other, R and
S, leave sufficient room for the wheels A, the pinion B, and the pillow-block a. The pinions B are
screwed on the wheels A, and grasp in the cogs of the moving power g. C may be in equal direction
with the wheels A. The cannon is, with its grape, connected with the shaft n by a muff; it turns round
its axis, and is at its mouth supported by the saddle U. The squared shaft f of the lower wheel C
passes through the post S and the saddle U, between which it is supported by a tressel T, and is im-
mediately behind the resting tressel V and the winding tressel Z, provided with the cog-wheels E and
G, which are fixed by means of wedges. The cog-wheel E grasps in D, placed above it, and causes the
boring-bar c and its screw-spindle d, to turn on their axis in a reverse direction to the rotation of the
cannon, by which the acting of the borer is strengthened. In order to produce a uniform and properly
measured advance of the boring-bar, the system of the screw with moveable box is applied, the cog-
wheel G working in the teeth of another one F, which contains the box of the screw-spindle d, and turns
round this latter with somewhat less celerity than the screw-spindle itself, by the working of the cog-
wheel D upon it. In this manner a slow, but uniform advance of the boring-bar is effected. The extent
of the pressure of the borer against the cannon depends upon the number of the wheel-teeth, as well as
upon the length of a screw-worm of the spindle, and may consequently be altered by a shifting of the
wheels.
In order to afford a clearer idea of the whole machine, we shall give a more circumstantial description
of its several parts, in whose construction various alterations can be made.
The shafts n and f are provided with moving-out apparatus, which are not constructed like the com-
mon claw-boxes; one of them is represented in Figs. 680 and 681. The shaft n n₁, is cut through at x,
and consists of two parts, of which the front one bears the spring-wheel, while the back one, 921, passes
through the post S, and terminates in a square for the connection with the cannon. Both shaft-parts
are connected with each other by a case, embraced at its front collar by a barnacle-ring f, which presses
against the knobs dd of the wheel, and causes a simultaneous rotation of the box and shaft. The front
part of the shaft n₁ is squared, and thus put in motion directly by the box, while the part of the shaft
n, inserted in the box, must be cylindrical, 80 that the box be put in again, by means of the fork a, at
every movement of the rotation. Suppose both shaft-ends inserted in the box were square, it would be
not only difficult to watch the moment when both shafts are in congruity, but also impossible to pre-
vent a shaking movement. The fork a moving round the support b c, fixed to the post S, embraces the
box at the groove of its weaker back-part, and leans against the projecting edges. Thus, if the handle
of the fork be pressed to the left, the box is moved out to the right, i. e. the barnacle-ring f leaves the
knobs d, and the movement of the shaft n is not connected with its other half n₁.
The saddle U is represented in Figs. 684 and 685 it has, like all other tressels, in its lower part a
socket for the shaft f. The slide o, forming the holder for the cannon-mouth, is adapted to every length
and diameter of the cannon, and is provided with adjusting disks polished with emery. The lower
part of the slide is cut off obliquely, and in conformity with the inclination of the wedge, moved by the
screws m n. Consequently by drawing the female screw m, the cannon can be lifted exactly to the
required height.
The supporting tressel T of the shaft f is represented in Fig. 686; it contains the semicircular socket
in its upper part. The squared shaft f is at all points, where it rests on the tressels, provided with
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brass boxes, which are circular at their outsides, and fastened at the shaft by means of small metallic
wedges.
Figs. 666 and 667 represent the resting tressel V, whose upper part contains the holder of the boring-
bar c. The latter being squared, it is provided with a box pp, Fig. 668, circular at its outside, and
turning round in the holder, together with the bar, yet not advancing like this. To the projecting
squared part of the box the toothed wheel D is fixed, which puts the boring-bar and screw-spindle in
a rotative movement. To the lower shaft f is fixed the wheel E, which can be kept in constant gear-
ing with the wheel D by the edge 00; otherwise the box might, together with the upper wheel, slip
out of the socket.
The tressel W, Figs. 682 and 683, supporting the spindle and lower shaft, has at its upper part the
slide b, and is cut out conformable to the diameter of the screw-spindle.
The hindmost part of the machine is formed by the tressel Z, Figs. 678 and 679, which allows a free
passage to the screw-spindle, and is for this reason perforated according to its widest diameter. Above,
the tressel contains the holder for the shaft of the wheel e, which allows to draw back the boring-bar
by means of the winch x, and at the same time to increase or decrease the pressure against the cannon,
if required. The wheel e works in the teeth of the cog-wheel F, which contains the female screw of
the screw-spindle, and is kept in constant gearing with the wheel G, by the edge pp. Thus, whenever
the boring-bar is to be drawn back, the wheel G is drawn off, and the lower shaft moved out.
Should it seem preferable to allow a spring-like movement to the boring-bar, the tressel V may be
entirely removed, and then the wheel D is to be fastened at the square end of the screw-spindle, which
now, together with the boring-bar, is moving onwards against the cannon.
The third system of the horizontally-working machines is a combination of the two other ones. The
arrangement of the wheel-work and shaft-sockets A and B is in substance the same as the above de-
scribed. The boring-shafts are provided with apparatus to move them out and in; yet the connection
of the cannon with the principal axis is arranged in an improved manner. The adjoined piece of the
grape has the shape of a regular prism, and is inserted into a box cylindrical at its outside at the end
of the axis is fastened a ring. In the cylindrical excavation, D, the inserted box, has a play of some
few lines. Three strong adjusting screws pass through the adjoined piece into the box, and by means
of them the cannon can be centred, if required.
In general the cannon is only supported at its mouth by the saddle G with the disk a; with great
calibres, however, a second saddle G, may be applied at the bottom piece or grape. The saddles are
made of cast-iron, and moveable in the grooves of the iron plates.
The sledge L, made of brass, terminates below in a guide, which is advancing in the excavation Y,
and cut out in such manner that it forms beneath the screw-spindles, two feet armed at the edges with
steel rails. At the middlemost and higher part of the sledge, the boring-bar is fixed either by means
of a bow and pin, or of two steel rails R, that are to be screwed on, and between which the square of
the bar is pressed fast by the screw d. The shifting of the borers and the taking out of the bore-chips
is so facilitated. The sledge is pressed against the cannon by two screw-spindles E and E1, passing
through the side projections of the sledge, and having their sockets in the iron posts B and N. The fe-
male screws are cut out in the brass of the sledge, and at both ends provided with steel armaments.
The back ends of the spindles, terminating in squares, bear the toothed wheels o and O₁, being in gear-
ing with each other by the equal wheel O2 and thus turning in the same direction, and with the same
celerity. The spindle E passes through the post N, and is provided with a handspike-wheel P, for the
movement of the machine.
Simultaneously with the sledge, a support K, for the turning off, moves along the cannon, and is pro-
vided with a female screw for the spindle. It has, like the sledge, a guide sliding on the iron plates or
special bolts, and through the upper part of which a brass wing H is moving, and terminates in a foot
gliding on the steel rails c c of the iron plate Q. The latter is, according to the various descriptions and
calibres of the cannon, fixed at the screw-holes x x, so that the rails cc run parallel with the cannon,
while the turner's chisel is always kept in a proper distance from the cannon's axis during the move-
ment of the support. At the front end of the wing H is a moveable rail or peg, for supporting the
turner's chisel; by means of an endless screw it can be put back or forward, and an index at its upper
side indicates the extent of the change.
At Douai, in France, a steam-engine, 12-horse power, moves four boring-benches, whose shafts make
10 or 12 revolutions a minute; at Toulouse, a water-wheel, 12 or 13-horse power, moves four boring-
benches; and at Strasbourg, one boring-bench is put in motion by four horses.
The movement of the cannon on the boring-bench, and the pressure required against the borer, de-
pend generally upon the material and calibre of the cannon. Is the rotation decreased, the pressure
may be increased, as otherwise the bit might generate a too great heat, and thus become weak. Iron
cannon and wide calibres must revolve more slowly than brass cannon and smaller calibres. In the
boring-mill of Liege, the cannon revolves once in 8 seconds, and in that of Douai it revolves at the rate
of 10 or 12 times a minute. It seems that 12 times a minute is considered as the maximum.
The pressure, depending chiefly upon the hardness of the metal, cannot be indicated precisely. In
the second of the horizontally-working machines, above described, the advance of the boring-bar de-
pends upon the number of teeth of the several wheels. If, for instance, the wheels B, C, D, E, and F,
have 36 teeth each, while the wheel G has only 34 teeth, the wheel F, together with the female screw
of the spindle, will make 34 of one complete rotation of the spindle; and thus the boring-bar will ad-
vance only by 1.20 of that distance, by which it would have moved onwards, if the female screw were
fixed. If the length of a screw-worm be half an inch, the spindle will advance by 3 X 1/08 = 3'8 inch.
Should the wheels B, C, E, and F have 36 teeth each, while the wheel D has 35, and G only 34, the
spindle will revolve at the rate of 36, and the female screw at that of 34 of one complete rotation of
the cannon, while the boring-bar is advancing by 30 X 30 X 1/2 = 0.0286 inch.
The following table gives the number of teeth both of the spring-wheels and of the wheels E and F.
Digitized
by
Google
681.
680.
224
672.
671.
W.
The
B
x
W.
T
y
=
NOT
6
OF
H
27
679.
678.
a
a
X
683.
682.
677.
8
WWW
3
N
DE
676.
a
K
%
12
o
a
c
P
T
G
©
G
a
%
M
W
R
If
a
of
"
G
669.
D
0
II
0
0
R
N
685.
684.
CANNONS.
P
3
a
674.
G
2.
-
c
c
1
лл.
E
uu
670.
R
a
2
©
a
E
.
II
B
Digitized by Google
a
(CED)
686.
"
el B
é
#
R
T
CANNONS.
225
The middle wheel of the lower axis, and that with the female screw, are at all events provided with 36
teeth; by inserting a fresh boring-bar, the proportion of the advance can be altered without much
trouble.
Number of teeth
Advance of the bo-
of the wheels.
ring bar by inches.
The Material, Description, and Calibre of the
Borer.
Cannon.
B,C,
During one
Remarks.
Eand
D.
G.
rotation of In an hour.
F.
the cannon.
From 48 to 24 pound cannon, mortars,
Brass cannon.
carronades, and howitzers, of wide
36
35
34
0.0286
10.29
The length
calibre
of a screw-
Plain borer and widening
From 18 to 12 pound cannon and
howitzers of small calibre
36
35
33
0.0428
15.41
worm is I
an inch.
borer.
From 6 to 4 pound cannon
36
84
33
0.0441
15.88
From 48 to 24 pound cannon, mortars,
The cannon
Iron cannon.
and howitzers of wide calibre
36
36
33
0.0416
14.97
revolvesat
From 18 to 12 pound cannon and
the rate of
howitzers of small calibre
36
34
33
0.0441
15.88
6 times a
From 6 to 4 pound cannon
36
36
32
0.0554
19.44
minute.
Fly-borer of the mortar-pieces and
Auger or
forehand-
auger of the carronades, and from
36
36
35
0.0139
5.00
borer.
48 to 24 pound iron cannon
Chamber-auger of the howitzers, and
36
36
34
0.0277
9.97
auger for all other great guns
Bottom-borer of the cannon, chamber
Bottom-
borer.
bottom-borer of the mortar-pieces,
and vault-borer for the holes of the
36
35
35
0.0148
5.148
mortar-pieces
To convey the cannon from the foundry to the boring-mill, a crane-carriage can be applied in case of
their being connected with each other by a railway; which, of course, is to be held aloft by supporting-
posts, that the cannon can be lowered down to the boring-bench. The carriage runs on four cast-iron
wheels X, on the rail a. (See Figs. 671 and 672.) Its upper frame, made of solid timber, bears two
shafts W, and W. T1 and T2 moved by winches Y. The shaft W, serves to move the carriage onward,
and the end of the rope cast round it is fixed to a hook in the intended direction of the carriage.
Sometimes this shaft is left out entirely, and the carriage provided at both ends with hooks to hang
ropes, which either are fastened to windlasses at both sides of the railway, or are connected with the
principal axis of the boring-mill by rollers. To the ropes of the second shaft is attached the draw-beam
Z by means of strong iron hooks, to which the cannon is fixed with ropes. The axle T1 is provided
with double ratchets.
By means of this crane-carriage the cannon is lifted from the pit, freed from the mould, and then
conveyed to the boring-bench, on which it is placed horizontally. In a similar manner it can be removed
as soon as the boring operation is accomplished.
Before the cannon is encased on the boring-bench, its eccentricity must be examined; for which
purpose it is to be placed on two separate saddles, where it is, by means of the trunnions, turned round
its axis and meanwhile examined. If the eccentricity nowhere exceeds four lines, the cannon may
forthwith be encased; but in the contrary case its centre must previously be precisely regulated.
For the purpose of severing or turning off the lost head, the lever A, Fig. 676, centred on a pin at the
front saddle or tressel F, or at a particular post, moves in a plane vertical to the cannon, and has in its
lower part a hole, into which is inserted the chisel-shaped blade C. At the lever's end is the weight P,
and above it a moveable ear or handle, serving as box for the support T. which, at its upper part is
provided with screw-threads. By means of this screw the chisel can be approached to the axis of the
cannon, while the weight prevents the rising of the apparatus. The boring-mill being put in motion, the
lost head is turned off to a minute remnant, whereupon a stroke completes the severing.
For the purpose of the cannon being centered, near the cannon a cross-piece of timber is put beneath
the boring-bar, which is then, by means of small wedges, to be brought to the required height and
direction. This done, and the front face of the cannon having been chalked, the borer is slightly pressed
against it, while the cannon revolves. If no shaking of the boring-bar be perceived, even by increasing
the pressure, the borer is correctly centred; but if it be the case, the boring-bar must, by the wedges,
be adjusted till no shaking is perceivable. Now the boring may commence.
The shape of the borer has in the course of time greatly varied. Formerly a hollow borer or wimble
was used for boring massively founded cannon over the core, as it was called. Having bored to a
certain depth, the core was, by a peculiar contrivance, pushed off, and upon this the boring operation
completed with borers. This was performed in boring-mills, working vertically.
At present there are chiefly four descriptions of borers in use, viz :-The auger, the bottom-borer, the
plain or calibre borer, and the widening-borer.
The terms of cross-borer, disk-borer, bore-knife, chamber and Ay borer, vult-borer, &c., have relation
29
Digitized by
Google
226
CANNONS.
partly to peculiar positions and shapes of the bits, partly to the place and manner of their application,
and can be ranged in the above-named descriptions.
The auger consists commonly of a bit of steel as broad as the first boring requires. Frequently
hardened iron is used instead of steel. This auger is used in the boring-mill of Liege. It has two
edges and an angular form in the fore part. The angle must be the more obtuse, the greater the motive
power, the pressure, and the hardness of the metal By this bit the first boring is preserved to the dis-
tance of four lines from the cannon's bottom, where it ends in a conical form. With middle calibres
the bore of the cannon is now only to be somewhat widened and polished, by means of the plain borer,
while with larger calibres one or more widening borers are still to be applied.
The older French auger, here and there still in use, consists of three blades, the first of which hav-
ing the form of the auger and widening the bore to two-thirds of the whole boring diameter. Behind
it, in the bit-head, is a hole, through which the second blade is put, that cuts onward and sidewise, and
widens the bore by eight lines. Behind, and in a right angle with this blade, is a third, which widens
the bore to the diameter required for its being polished.
In German boring-mills, augers are used; they leave four lines of the bore, and penetrate to near the
bottom of the cannon or howitzer. In recent time the form of a saw, like that of the bore-knives, has
been adapted to the auger; and thus, by one single boring, the operation can be completed so far that
only the plain borer is still to be applied. In Vienna the augers have not only this form, but are also
provided with shovel-edges.
In order to be assured of the correctness of the first boring, a strong wooden rule as broad as the
bore, is to be put in; and in case it can penetrate to the bottom, and be turned without any obstacle,
the boring is faultless and can be pursued.
The boring with the auger is immediately followed by that with the bottom-borer, though with larger
calibres, an application of some widening borers is to be made previously. The bottom-borer is intended
to widen the cone made by the auger, and give the required shape to the bottom. Its boring-blade is
three or four lines thick, and forms a rectangle, rounded off in the fore part, which at the same time is
the cutting part. The frame or head of the borer is, by means of its tail and by two screws, fixed
to the boring-bar.
The next is a bottom-borer, as constructed in France: and another one intended for giving a hemi-
spherical form to the bottom. The latter can be forthwith applied, in which case it consists of a
metallic head provided with two side-blades, and an upper rounded edge; four wooden prisms secure
the run of the borer. Frequently the head receives a cylindrical form, and the boring-blade is inserted,
in the way of a plane-iron; in which case the borer is called a disk-borer.
The bottom-borer is followed by the polishing or plain borer, which commonly only takes away the
two last lines of metal and polishes the bore, by freeing it from boring-rings. Its head forms a cylin-
der, a quarter of which is cut out, and on the level of its edge an oblique steel blade is screwed fast.
The screw-holes in the blade are elliptically formed, as the boring is to be repeated several times,
and meanwhile the discharge of the blades is gradually. increased until the normal calibre is at-
tained.
The plain borer is used in the boring-mill of Liege. It consists of two small boring-blades, which,
in the fore part, have exactly the form of the bottom, and are fixed to the tongue of the boring-head
by means of three screw-bolts. The discharge of the blades is effected by strips of tin-plate inserted
behind their back.
The boring of the howitzers and mortars is in general done in the same manner as that of the cannon,
with the only exception that a greater number of borers is applied. The auger is succeeded by the
calibre-borer of the chamber; it is intended to polish the chamber; and as its blades are crossing each
other, it is also called the cross-borer. The third and fourth borers have the same frame, into which
the blades are inserted one after the other. At last follows a polishing-borer. The gradual discharge
of its two blades is effected by inserted small strips of tin-plate.
Field-howitzers, with spherical chambers, are in France bored with borers of the following descrip-
tion :-A common auger makes a bore, which is by two lines less wide than the chamber. Next fol-
lows the borer which bores out the fly or middle part of the bore to two lines of its diameter: a cylin-
der of the same diameter as the first bore serves as guide to it. The third borer has a similar guide,
and is intended for boring out the spherical chamber. Then follow the polishing-borers
The mortars are, in the boring-mill of Liege, bored in the following manner:-First is applied the
small auger, which makes the bore by four lines less wide than the chamber. Next follows the great
auger, which is inserted into a particular boring-bar, and penetrates to the fore part of the chamber. Its
blade can either be formed single, or be composed of three blades; the joined piece of the boring-head
serves as support. After this the chamber-borers are applied.
In case the chamber is to be conically formed, the bore-knives are commonly used, which are con-
structed in the following manner:-At the boring-bar is a long groove for receiving the dented iron rail,
which is held by the bands. The bar is moved by the axle, and by means of the lever, and at its
front end is a notch, into which the boring-blade is inserted after the plate has been removed. The
lever is worked by an operative. The first bore-knife to be inserted is in the form of a saw, and brings
about an undulatory surface in the chamber; yet with the advantage of taking away much metal. The
second one is plain, and cuts away all elevations completely.
Another instrument for boring conical chambers is represented by Figs. 687 and 688. The blade a is,
by means of the bar b, moved onwards in grooves formed by the lists p, and is, like the bar b. screwed
in the plates m and n. The surface of the instrument is plain, whereas the lower base is rounded
according to the form of the chamber, (see Fig. 691.)
The boring of spherical chambers is very different; it requires a great number of borers. To show
their contrivance and application, we will shortly describe the boring of a French foot-mortar. First
an auger is applied, whose diameter is by 4 lines less than the neck of the chamber. Next follows the
Digitized by
Google
CANNONS.
227
o
699.
a
"П
b
0
8
a
8
697.
B
0
es
700.
687.
0
0
689,
Rq
й
688,
690.
0
0
701.
0
0
702.
0
0
THE
72
6
R
A
698.
u
703.
691.
704.
715.
707.
E
#
711.
A
708.
d
R
709.
712.
R
713.
A
710.
-
705.
714.
.
696.
716.
o
o
692.
B
694.
11
8
a
717.
706.
i
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A
8
718.
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719.
-
0
.
0
8
693.
695.
L
00
M
©
y
720.
721.
722.
723.
724.
725.
726.
727.
728.
Digitized by Google
228
CANNONS.
blade, together with another rounded in accordance with the form of the chamber. Fig. 699 illustrates
the shape of the borings, which are marked with ciphers in their order of succession. All these blades
are inserted into the head of a particular boring-bar. The chief part of the head is provided with a
tongue, and a cover or moveable lip B, on which all blades are screwed. The grooves of the blades
are adjusted to the lists. Now as soon as they have attained the bottom of the chamber, they glide
backwards in consequence of the pressure, and commence at the same time the operation of boring out
the chamber. First, the blades C, then the blades D, and at last the blades E, are applied, and thus
the parts 4, 5, and 6 of the chamber, (see Fig. 699,) are successively cut away. Finally, to complete
the boring, the blades and the polishing-borer are applied.
Figs. 689, 690, and 691 represent a borer for giving to the chamber the form of a pear. It is applied
after a bore as wide as the chamber-neck having been made. The boring-head has a groeve q to let
out the bore-chips; and in another groove, partly covered by the rails p, run the plates m and n, round
which the blade a, and the bar b are fixed. It may finally be remarked that the pear-formed chambers
are at present out of use.
The turning off is at present commonly done conjointly with the boring of the cannons. Only in
boring-mills working vertically, a separate turning-lathe is required, which consists of two long beams
6 or 8 inches asunder, and short cross-beams. In the inside grooves of the long beams are inserted two
moveable strong oak blocks, provided with knobs or bunchings at the front, to be inserted into holes
of the front and back pieces of the cannon. Near the trunnions is a disk, consisting of two halves, fixed
and connected by an endless thong, with a fly-wheel of five or six times greater diameter. In this
way the cannon is turned on its axis.
The turning off can be done either off hand, or by clamped chisels. The first method has many ad-
vantages, yet requires great labor, and an experienced operative; and the apparatus for working by
clamped chisels on moveable supports is very expensive, however applied to brass cannons. The common
method is the working off hand combined with fast supports.
The turner's chisels are provided with long wooden handles, and are either crooked (as the French)
or straight, (as the English.) The French chisels are dented at the back of the incurvation, to prevent
their slipping from the support. There are especially two descriptions of them, the one intended to
rough-turn with, and the other for planing, (see Figs. 701, 702, 703, and 704.) The English chisels are
straight, and mounted with either triangular or quadrangular pommels; the handles are fastened to
them in right-angular direction.
A moveable support according to the old French system is represented by Figs. 692 to 695, and worthy
of description here, as it can yet be applied with some modifications. The chisels, Fig. 696, are by
means of a bolt fixed in the iron rail A, which in the wings of the brass support N can be moved on-
wards and backwards by the screw B. The latter passes through the back part of the support,
strengthened by the steel plates q. To prevent the rail A from lifting, the two cross-pieces a a on the
support, are provided with female screws for the pressing-screws C. The support N rests on the brass
plate M, and is moved on it by the screw-spindle D, which passes through its midst, where the two ends
of the screw-worm are armed with the steel plates Y. The lowest part of the support consists of a
foot running in a furrow of the plate, and regulating the progress. For the purpose of facilitating the
movement, and maintaining a uniform and easy progress, the steel rails z z are inserted along the plate.
At one end the screw-spindle is provided with a toothed wheel in gearing with the winch P, by means
of the endless screw L According to the older system, the plate was fixed to the boring-bench by two
screw-bolts passing through the cuts X X; but at present one single bolt is applied, and passes through
the middle of the plate. The chisels used with the moveable supports are in general shaped as is shown
by Fig. 696, a and b. For turning off the moulding and grape of the cannon, particular chisels are
used, such as represented by Fig. 696, b and k.
Before the turning off begins, the cannon is placed so that the trunnions lie exactly in a horizontal
plane, and then, by means of the instrument, the middle line of the cannon's surface is to be as-
certained. Upon this the moulding, edge-rings, and vent are pointed out and marked, so as to
prevent the chisel from planing these points. In turning off hand, the beginning is commonly
made with the bottom moulding, next follows the edge-ring, and then the grape, and thus the opera-
tion proceeds to the head-moulding, while successively the chisels c, d, e, f, g, a, b, h, and i, Fig. 696,
are applied. The trunnions are to be rounded off, either off hand, or by a particular contrivance
of the machine, illustrated by Figs. 735 to 739. The cannon rests in cross-blocks or standards, and the
machinery in the frames B. The spindle m consists of two parts, one of which bears the roller r, round
which the string d of the weight Q is coiled. The screw of the spindle is adapted to the female screw
in the capsule P, to which is fixed the fly-wheel D. Another machine is represented by Figs. 731, 732,
733, and 734, and all its parts are made of cast-iron or steel. The sockets D and E for the cannon are
by screw-bolts fixed in slits of the iron plates of the boring-bench. Each of the standards E, Fig. 733,
consists of two parts, whose projections v and t grasp one into the other. The screw g serves for ad-
justing the required height of the upper part. The standards A A are, like the tressels of the boring-
bench, fixed by screw-bolts in the long slits pp, (see Fig. 663.) Through the lower part of both stand-
ards passes the squared axis f of the boring-bench, bearing the round boxes d d, and the wheels C.
Through the upper part of the standards passes the spindle m, on which are screwed the blade-baskets
n, and which bears at the same time the wheels B, that, conjointly with the wheels C, bring about the
simultaneous movement of both spindles. Each spindle is perforated in its axis for the reception of
the steel rod q, which at its back end is provided with a screw-turn, and at its front end with a small
female screw. The pressure against the cannon is effected by a strong spring 2. The basket n con-
tains four blades b, (see Fig. 734,) which by the pressing-screws 8 are pressed against the trunnions.
Those parts of the the cannon which cannot be turned off in the above-described manner, because the
trunnions and handles hinder it, are elaborated by the chaser or engraver. The instruments he makes
use of are represented by Figs. 720 to 727. First, he applies the gouge, (Fig. 723,) carving furrows, whose
Digitized by
Google
CANNONS.
220
g
d
8
9
0
0
&
a
799.
I
730.
734.
733.
I
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E
a
E
b
A
8
746.
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a
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731.
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25
B
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735.
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741.
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738.
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743.
739.
749.
e
Digitized by Google
230
CANNONS.
edges he then takes away by the plain chisels, (Figs. 720 and 721,) upon which the surface is freed
from all inequalities by means of the vaulted mallet, (Fig. 728,) and of the instruments represented by
Figs. 724 and 726. The elaboration of the angles and ornaments is accomplished by means of the
burin, (Fig. 722.) Finally, the chaser elaborates the written characters, using the instrument, Fig. 727,
called in French traçoir, and the common gravers. Fig. 725 represents a scalper or raspatory for dim-
ming the metal between letters working in relievo.
We will give here some statements about the difference in time between the older and modern boring
systems. Formerly it was computed that the boring of a 24-pounder might take up 8 or 10 days, its
turning off the same space of time, and the transport from one machine to the other 4 days; conse-
quently in total from 20 to 24 days, or from 200 to 240 hours. At present a 24-pounder is bored in 50
hours, the simultaneous turning off prolongs this time to 60 hours at the most, and the transport
takes scarcely 10 hours; thus the whole work is done in 70 hours. The boring of smaller calibres is
at present completed in 14 hours, and that of the mortar-pieces in from 20 to 60 hours. In the French
boring-mills the auger advances t of an inch in an hour; the bottom-borer completes its work in an
hour, and the plain borer advances one inch in an hour, as also the widening borer. In the modern
German boring-mills the borers advance 11 inches in an hour.*
To make the cannon completely ready for service, the boring of the vent, the placing of the aiming
ruler, and the fixing of the priming contrivance remain to be done. For placing the aiming ruler, either
a deepening is made in the back edge-ring, or a hole bored in the bottom-piece of the cannon, in the
performance of which is used the borer represented by Fig. 744. The frame required for this opera-
tion consists of a standard A, of whose four feet C, only the two back ones are to be seen in the figure.
The cannon rests on this standard in a horizontal position, is at its ends supported by the wedges C,
and at the trunnions by the blocks b and wedges a, and is fixed by means of the bands f and cross-
pieces g. Between the posts O, P, Q, and R, is the beam D, serving as a lever, having its fulcrum at m,
and being pressed down by the weight P, by which its front end with the blade G lifts the guide I.
Between the cross-rails of the bench F, the guide I can only move vertically up and down at its upper
end it is armed with an iron frame o, which can be adjusted by the screws ii. It is at the same time
provided with a steel plate, through the conical deepening of which the borer T is put.
The boring of the vent of the cannon is performed either by a drill (which is turned to the right and
left alternately) or by the borer T, (see Fig. 744,) which latter is turned in one and the same direction.
Commonly the former is used, especially in the boring-mill of Liege, where the machine for this pur-
pose, represented by Figs. 729 and 730, comprises two frames, one for the cannon, and the other for
the drill. The frame for the cannon consists of two cross-beams a a, united by a long beam b; in the
former the iron rails v are inserted and fastened by the wedges r; the cross-pieces c are moveable.
The tressels m m, with the disks o o, are supporting the cannon at and can be moved aside,
if required, on the cross-pieces c. The cannon is placed in such a manner, that while the axis of the
bore lays horizontally, that of the trunnions is vertical. The boring-apparatus consists of a bench d,
fixed, by means of the bolt e, to a plate, which rests on the posts q and p, and on which the bench
turns on the bolt e. The drill f is moved onwards against the cannon by a spindle, or by a dented bar
and winch, and is turned by means of a bow, Fig. 740, made of bamboo or old steel blades, and whose
string (of catgut or horsehair) is coiled round the boring-roll. By moving the bow to and fro, the borer
turns alternately to the right and left. For adjusting the bench, the ruler, Fig. 748, is applied. The
line a b marks the axis of the vent, and the line c d indicates the length of the cannon's bore. To this
latter line the notch x extends. The line fg corresponds to the notch y. By means of this ruler the
point for the vent can be exactly fixed. As regards the borers, in Liege first the auger C (Fig. 747)
is applied, then the plain borer B, and finally the borer C. The bits are of the best steel.
To prevent the deterioration of the vent by the violent discharge of gas from it in the moment of the
explosion, there must be inserted in it a pipe of iron, or of refined copper, which is replaced by a fresh
one as soon as it is worn out. For this purpose the pipe has on its outside a male, and the vent is pro-
vided with a female screw. On the lathe the pipe receives the form a in Fig. 697. The lower part is made
conical, the next following cylindrical, and the upper part squared. The boring out of the vent in the
French foundries is performed by means of a machine represented by Figs. 697 and 698. The cheeks
B, resting on two standards A, receive the rails C, D, and E, of which the two latter are fixed by the
wedges n n. The pressure of the drill p is effected by the pressing-screw Q The cutting of the screw-
worm is performed on the block x, Fig. 700, by means of barnacles or pincers, Figs. 741, 742, and 743.
The pipe or core a is clamped in the vice b, fixed to the block x, which in its lower part is firmly im-
mured. The fork-shaped body A of the pincers runs out in a long arm the cheeks D and E are
inserted into the furrows of the arms F; the cross-piece B is held fast by the screws x x, and forms the
female screw for the end of the lever C. The pincers are turned horizontally round the pipe by
two operatives, while a third one is watching the operation. To form the female screw in the vent,
Field-guns cannot be conveniently served when they have less than one hundred and fifty pounds of metal to each
pound of shot, and battering-guns require at least two hundred pounds of metal to each pound of the shot. With any
less weight the service of the gun is very difficult, from its excessive recoll; therefore. lightness is not a desirable point
in the construction of cannon.
Strength is always desirable; it should be secured, but not at the expense of any other important point. If it were pos-
sible to fabricate sound and strong guns of wrought-iron, they would be found deficient in hardness. The projectiles used
are of cast-iron, a material much harder than wrought-iron consequently, the wrought-iron gun is soon indented and worn
so much as to prevent all accuracy in firing, and it then is worth little or nothing.
Leaden balls are used in small-arms but they are Inadmissible in cannon, as the great heat of the exploded gunpowder
melts the lead, more or less, and changes the form of the ball, thereby reducing its range; besides, lead has not sufficient
tenacity to enter hard substances, and therefore is not a suitable material to be used against ships and batteries. Wrought-
iron is also more liable to injury from rust, than bronze, or cast-iron and the smallest crack admitting moisture, would, of
itself. in time, seriously injure the gun. The first cost of wrought-iron cannon is the same as that of bronze, and more than
six times that of cast-iron. Bronze guns, it may be remarked, after being too much worn for service, can be easily recast,
whereas the old wrought-iron is useless for refabrication, and of little value, in such large masses, for any purpose.
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CANNONS.
232
CARDING ENGINES.
the horizontally-working boring-bench, represented by Fig. 719, formerly was used, and is in some
places still in use. But at present the vertically-working machine (Fig. 745) prevails. It consists of
the frame A, B, C, D, E, a screw-spindle T, (whose female screws are in A and C,) and the borer S.
The cannon rests on the beam E.
The borers commonly applied are, first the auger, (Fig. 715,) then some widening borers, and a pol-
ishing-borer of the shape in Fig. 712. With old battering trains, or cannon of fortresses, in which the
pipes are inserted in a heated state, a greater number of borers are required. In France, first an
auger is applied, and then six others in the ensuing order of succession : Figs. 708, 709, 710, 711, 712,
and 713.
CARDING-ENGINES. BREAKER AND FINISHER.-These very effective machines, Figa 778 to 783,
are manufactured at the machine-shop, Lowell, Mass. Figs. 778, 779, and 780 represent the Card-
Breaker, with 14 tops or flats; and Figs. 781, 782, and 783 represent the Finisher, which has 22 topa.
778.
⑉
Front View. SCALE.-5 inches = 8 feet.
779.
2
o
0
Driving-end. SCALE.-5 inches = 8 feet.
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CARDING ENGINES.
233
There are but few mills in the United States that use single carding ; the greater part use Breakers
and Finishers, even those that manufacture the coarsest goods. In the Eastern district the general
breadth of the cards is 37 inches, and diameter of main cylinder 36"; doffing cylinder 18"; feeding
rollers 14". The main cylinders are made of cast-iron, and covered with broad filleting, instead of
sheets. The average speed of the main cylinders is about 100 revolutions per minute. In the Rhode
Island district the cards are made of various breadths, from 18 to 36 inches, and are principally wooden
780.
o
.
Gear-end. SCALE.-5 inches = 8 feet.
cylinders, covered with sheets. In the Southern district the general breadth of the cards is 24" to 80".
There are some cast-iron cylinders covered with sheets. The average speed of the cylinders in the two
latter districts is 110 revolutions a minute, and diameter 36 inches. In order to make smooth, level
781.
D
D
Back View. SCALE.-5 inches: = 8 feet.
#
yarn, it is absolutely necessary to have the cotton well cleaned and carded; if the tufts or knots of cot-
ton are not perfectly teased out, and the fibres well separated at the latter process, the fleece delivered
from the doffing cylinder will exhibit inequalities, or appear what is technically termed clouded ; and
from card-ends of that texture, it is impossible to make good yarn. The stripping is performed by two
persons one, the top-stripper, begins at the first card in the series, and strips every second top all over ;
30
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234
CARDING ENGINES.
that is, the 1st, 3d, 5th, 7th, 9th, 11th, &c., until the whole of the tops are stripped in two or three
courses. The cylinder is also stripped by the cylinder-stripper, thus keeping up a contsant system of
stripping all the time the machinery is in motion.
For the purpose of sharpening the teeth, when a carding-engine is first clothed with new sheets,
fillets, &c., the cylinders are put in motion the right way, and a light emery-board, about 4 inches broad,
is traversed over the top of the cylinders, with a very delicate hand; this is called facing up the teeth,
because the points of the wires are running against the board, and is intended to cut down any single
782.
alli
C
Driving-end. SCALE.-5 inches = 8 feet.
wires that may be too long. After running the cylinders in this way for about fifteen minutes, their
motions are reversed, and small cast-iron cylinders, coated with emery, (Fig. 781,) are mounted on the
main and doffing cylinders; these are denominated fast-grindera, and which, after being properly set,
are caused to revolve in an opposite direction to the card cylinders. This operation is continued until
783.
6
B
9
Gear-end. SCAL inches = 8 feet.
the whole of the teeth on both cylinders are ground down to one uniform length; but during the process
of grinding, the emery cylinders are made to traverse a little each way, so as to grind the wires to a
round point, and prevent them from being hooked. The cards are then dressed up-first with a brush
dusted with chalk, and then with emery-boards, called strickles; this latter process is called sharpen-
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CASK-GAGING.
285
ing, and is continued daily to the Breakers, and every second day to the Finishers. The fast-grinders
are not applied above once a year, or only when the cylinders on some parts of the surface have become
higher than on the other parts, or, technically, of the truth." By this method of grinding the cards
when necessary, and sharpening them every working day, they are always in good order, and conse-
quently produce more perfect work also, when the practice of sharpening is continued daily, it can be
done in much less time two men can easily sharpen thirty carding-engines in the space of four hours
The card-belts being all fitted with buckles, no time is lost in making them long or short, for the pur-
pose of reversing the motion of the cylinders. The tops are also brushed out and sharpened once a
week.
Fig. 778 is a front elevation of the Card-breaker.
Fig. 779 represents the driving-end; and
Fig. 780 the gear-end.
Fig. 781 is a back elevation of the Card-finisher.
Fig. 782, the end elevation, (driving-end.)
Fig. 783 represents the gear-end.
CAMPHOR WOOD. See WOODS, varieties of.
CASE HARDENING. See DETAILS OF ENGINES, and HARDENING AND TEMPERING.
CASK-GAGING. The rules hitherto given and used for gaging casks are either erroneous, imprac-
ticable, or uncertain; so much so, that at best they can only be counted mere guess-work: first the gager
has to determine by observation the variety of the cask; when he has made up his mind as to the
variety, he commences to calculate its contents by an erroneous rule, if brevity be required, thus heaping
error upon error; or by some long calculation or other, which he is told is correct, of the working of
which he is not sure, and thus uncertain as much as before of the quantity it contains.
If he performs the calculations on his slide rule, again he has to guess at what the result is: 80 he
guesses the variety of the cask, prepares its dimensions, before applying them to the slide rule, by an
erroneous calculation, and then the result is uncertain, even if he has hit upon the right form and
prepared the dimensions correctly.
The following were the vague directions given to the gager, to determine the form or variety of a
cask :-
"1. When the staves of the cask are much curved or arched, it is supposed to be the middle frustum
of a spheroid, and is called the first variety.
"2. Where the staves are not quite so much curved, the cask is taken for the middle frustum of a
parabolic spindle, or the second variety.
Where the curvature of the staves is very little, it is supposed to be of the form of the frustums
of two equal parabolic conoids, and is termed the third variety.
"4. If the staves be straight from the bung to the head, the cask is taken for the frustums of two
equal cones abutting or joining upon their greater bases, which is the fourth variety."
From these directions it is impossible to determine the variety of the cask, excepting the fourth, and
that rarely occurs. Without depreciating the rules hitherto given any further at present, we shall give
one which is at once simple in practice and certain in its results, let the variety be what it may; after
which, we shall point out the absurdity and uncertainty of using the former rules. Before we lay down
the principles upon which casks ought to be gaged, it is necessary to explain a new instrument, which is
a tape, and may be added to those already in use: viz. the cross-callipers, long-callipers, the head and
bung-rods, which require little or no description, and may be less in use than they formerly were.
The tape here referred to is a box-tape, and may be of any given length, with two lines on it, one on
the face, and one on the back; the line on the face is not a line of inches, but expressed in mean
diameters, each principal division being 3-14159, &c., inches, so that when any utensil is girted with this
tape it gives the mean diameter at once, instead of the circumference; and the line on the back points
out the area in gallons for such a mean diameter. Therefore, any circular vessel girted with this tape
gives the mean diameter in inches, and the area in gallons, of that section of the vessel where the
measurement is applied. For instance, suppose the circumference of a circle taken with this tape to be
45.7 divisions, (which is the mean diameter in inches,) opposite this number on the other side will be
5-916 gallons, the area of the circle.
In gaging, where the area is computed in gallons or bushels,
784.
&c., we consider the depth or thickness one inch. Thus, if we
C
say the area of a figure is 100 gallons, it is understood if
liquor or any other substance be placed on the surface of that
B
A
figure one inch in depth, it will measure 100 gallons; and 80 of
bushels, &c.
To take the dimensions of a cask standing.-The thickness
F
E
of the staves is the first thing to be ascertained, whether the
cask be standing or lying; this may be found from the pro-
jecting chimbs very accurately. When the cask is standing, the
external length may be found thus -Lay any straight rod
H
G
across the centre of the head, as AB, of sufficient length to
extend beyond the bulge; then set another straight rod or
inches upright, touching the bulge, as CD, and intersecting
K
1
the rod across the head, observing that the upright rod is at an
equal distance from the chimbs at bottom and top; then A M
is the external length required. The internal length of a cask
is easily found if there be a hole in the head, which note down,
M
as well as the external length. Next take the internal length
N
D
from the external, and divide the remainder by two, which set
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CASK-GAGING.
off from m to A; then opposite to a, and as nearly perpendicular to CD as possible, mark the cask;
to m A add one-fourth of the internal length, which set off from m to E, opposite, as before; mark the
cask opposite E; and 80 on at c', d, and é, increasing the distance one-fourth the internal length each
time. In two or three places mark the cask in like manner, in order that the tape may pass round
the cask in circles parallel at the places marked, viz. the surface of the liquor at top and bottom, at
the centre of the cask or bung, and in the middle, between the head and bung and between the bot-
tom and bung. When the diameters at the head and bottom are equal and the bulge uniform, we only
require three girths, viz. at the head and bung, and in the middle between the head and bung, F E and HG.
On the tape, opposite any circumference taken in mean diameters, we find the area in gallons cor-
responding to such a circumference, as before observed; but as the diameter found includes twice the
thickness of the stave, this must be deducted: on the face of the tape then opposite to the remainder,
we find the area of the internal circle corresponding to this internal mean diameter, and may be set
down as the girts are taken.
To find the content, when the cask is regular; or rather, when the diameters of the heads at bottom
and top are equal, and the bulge uniform and central
Add together the area at the head, four times the area of the circle in the middle between the head
and bung, and the area of the circle at the bung or centre of the cask; the sum multiplied by one-sixth
the length is the contents.
When the cask appears of an irregular shape.-Add together half the sum of the areas at top and
bottom, the area at the bung, and twice the sum of the areas in the middle between each head and the
bung; the sum multiplied by one-sixth the length is the contents.
Suppose the internal length of a hogshead is 42.25 inches, and the girts at the head, bung, and in the
middle between them, (after allowing for thickness of the staves,) to be 1742, 2.992, and 2.494 gallons
respectively; what is the content
Area of head = 1742
Area of middle = 2.494, and 2.494 X 4 = 9-976
Bung = 2-992
14710
14.71 X 42-25 = 621-4975 hence 6214975 ÷ 6 = 103.5829 gallons, Ans.
By the Slide Rule.Set 6 on B to 1471 on A; then will 103.583 be found on A, against 42.25 on B.
It is worthy of remark, that in using the tape it matters not what shape or variety the vessel is of,
providing it has a tendency to be round; for out of the many examples given in the above-named work,
comprising the different varieties, there is only one in which it differs from the strict mathematical rule,
and that a mere fraction of a gallon; while in the others it agrees to two and three places of decimals,
and in many cases farther: it also appears of no consequence whether the bung diameter exceeds the
head diameter by more or less than six inches, on which so much has been built in previous works on
gaging.
There is an irregular standing cask that girts in five different places, as follows:-
At the upper end = 1.714 gal.
half-way between the top and bung = 2.415
at the bung = 2-918-
half-way between the bung and the other end = 2.549
at the lower end = 1828
How many gallons does it contain, the length being 42 inches 1
Area at top = 1714
Area at bottom = 1.828
2 ) 3.542
1771
Area of bung = 2.918
2.415 X 2 = 4830
and 2.549 X 2 = 5-098
14617
42÷6=
II
7=f = the length.
Ans. 102.319
To take the dimensions of a cask lying.Girt it round the end with the tape, as far from the end as
will be equal to the thickness of the head and projecting chimb; this will give the area of the head in-
side,* (when the thickness of the stave is allowed for ;) then take the circumference at the bung and
between the head and bung, as directed in treating of the standing cask; but if the cask lie in a position
that renders it difficult to be measured with the tape, the diameter must be taken with the rod, taking
care that the rod meets the stave opposite to the bung-stave, and that the bunghole is in the middle of
the cask, and to allow for the thickness of the wood at the bung:-with this diameter find the area on
the tape,-or, by the instrument-See SLIDE RULE.
Next take the length of the cask, which is best done with a pair of callipers; but if those be not con-
venient, the following method may be adopted:
Apply any straight rod to the bulge of the cask, as HB, in such a position that each chimb of the
It was usual to take the distance from the inside of the chimb to the outermost sloped edge of the opposite stave, and
count it the head diameter of the cask inside; but this cannot be relied on.
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CASK-GAGING.
237
cask shall be equally distant from the rod, and two other straight rods being put across the
ends of the cask, as G H and BA; then will the distance HB, be the external length of the cask;
from which subtract as much as the staves project over
the heads, together with the thickness of the heads, and
785.
the remainder will be the internal length. Care should
H
F
D
B
be always taken to know whether the ends of a cask are
equal or not; if not, it should be treated as in the last
example.
Let HA represent a cask whose chimbs project 1.25
inches, and the thickness of the head 1 inch, also the ex-
ternal length or distance IB=82: how many gallons
K
will it contain, the three girts being as follows:-
at either end 11 inches from the chimb 25.
at H, the centre or bung 285
and in the middle at OP 27.4 inches.
G
C
These being the gross dimensions, when we move two
E
inches back along the tape for the thickness of the staves,
we have
the area of the head = 1.498 gallons.
the area of the bung = 1.989 -
and of the middle section 1828 -
Inches.
Again, the external length = 32.8
the projection of the two chimbs = (1-25 X 2) = } = 45
and the thickness of the heads = X 2 = 2-0
Hence the internal length = 28.3
Then to find the content,
Area of head = 1.498
Area of bung = 1.989
4 times area of middle section = 7.312
10-799
10-799 X 28.8 (the length)
=
509353
gallons.
6
Thus far we have shown methods sufficient to find the contents of any cask, let its form be what it
may, and also the mode of taking the dimensions whether the cask be lying or standing; we shall now
revert to the rules heretofore practised by the (English) Officers of Excise, in order to show how near
they come to the truth, and with what certainty they can be depended on.
The usual custom for ascertaining the content of a cask was to find a mean between the head and
bung diameters, 80 that this mean diameter would be the diameter of a cylinder the same length as
the proposed cask, and nearly the same capacity.
To reduce each variety to a mean diameter, the following factors or multipliers have been adopted:-
for the first variety 68, for the second 62, for the third 55, and for the fourth 5; 80 that if the differ-
ence between the bung and head diameters be multiplied by each of those for their respective variety,
and added to the head diameter, it will give the mean diameter, when the difference between the bung
and head diameters is 6 inches or less.
Let the following diagram represent the four varieties of
786.
casks, each of whose bung diameters AB is 26.5 inches, their
A
head diameters = E inches, and the length being
o
E
28.3 inches; how many gallons will each contain
For the first variety.-From the (bung diameter)-(head
diameter) = = then 3.5 X (fac-
tor) = 3.5 X 68 = 2.38, and this added to the head diameter
will be 23- + 2.38 = 25.38 the mean diameter. Again,
(2538)* = 644'1444, and 644.1444 X (283) the length, gives
18229-28652.
1822928652 ÷ 353-035 = 51636 gallons, the content.
For the second variety.-As the difference between the head
D
F
and bung is 3.5, and the factor for the second variety .62, we
have 35X62=217, and 2.17 +23=25.17 the mean diame-
B
ter; then as above, (25-17)* X 283 = 6335289 283 = 17928-86787.
17928-86787 ÷ 353-035 = 50.785 gallons, the content.
For the third variety.-(Difference of diameter) (factor) + (head diameter)=(3.5X5 + 23=24'925
the mean diameter; and 24-925 X 24-925 X 283 = 17581.5342, which divided by 353035 gives 498
gallons, the content.
For the fourth variety.-(3.5 X 5) + 23-24'75 the mean diameter .. 24.75 X 24-75 X 28.3 =
1738551875, and 17335-51875 353-035 49104 gallons. Where the divisor 353-035 is used, the
factor or multiplier 002832 may be substituted; thus, 1733551875 X 002832 = 4909, nearly the same
as above. If the bung diameter exceeds the head by more than 6 inches, the following factors must be
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CASK-GAGING.
used :-7 for the 1st variety; ·64 for the 2d; .57 for the 3d; and 52 for the 4th. But even were there
any certainty of determining the variety of the cask, much reliance could not be placed on these rules;
however, they may often serve as a check upon other methods, and with the assistance of tables can be
used with much expedition; for let us take the mean diameter of the first variety in the last example
at 25.4, and opposite 25 inches and under 4 in the table, we find the area = 1.8275. .. 18275 X 283
= 51-7 gallons, very nearly the same as before; thus we see if the area of the mean diameter of any
variety be found, and multiplied by the length of the cask, the product will be the content.
The nearest method to the truth that has hitherto been practised is, by taking the diameter at an
equal distance from the head and bung; but to determine this diameter before the introduction of the
tape was attended with some trouble, though the following mode seems easy enough in practice.
Lay a straight-edge touching the bulge of the cask in the middle, as HB at F, Fig. 785, the internal
length and bung diameter being known; set off on HB from the centre F of the cask towards either
end one-quarter the internal length, as at D; then the distance from D to the stave, added to the thick-
ness of the stave and doubled, will give the excess of the middle diameter above the bung, and this
taken from the bung diameter will give the middle diameter.
Let the bung be 32 inches, the distance from D=1 inch, and the thickness of the stave= 75 of
an inch; what is the middle diameter 1+75=175, and 175 = .. 32 - 3.5 = 285 the
middle diameter o P.
When this diameter is obtained, and having the head diameter, the bung, and internal length of the
cask, observe the following rule: To four times the square of the middle diameter, (or to twice the middle
diameter squared. which is the same,) add the squares of the head and bung diameters; the sum mul-
tiplied by one-sixth the length, and the product divided by 353035, will give the content in gallons.
Taking the middle diameter as found above at 285 inches, the head 24, the bung = 32, and the
internal length = 42 inches respectively; what is the content
280 and 57"
= 3249 = square of twice the middle diameter,
or (28.5)²X
= 3249 = the same.
Then (head diameter): (24)' = 576
Also (bung diameter) = (32)2 = 1024
4849
1/6 of the length = of 42 = 7
353-035)33943(961463 gallons.
This rule is as near the truth as any numerical one that can be applied, when the middle diameter is
taken correctly; nor need there be any attention paid to what variety the cask belongs. The above
rule is similar to the one given with the tape, for if the area of each diameter be used instead of their
squares, the rule will become thus :-
To four times the area of the middle diameter, add the
787.
areas of the bung and head diameters; the sum multiplied
by one-sixth the length, will be the content.
C
Another method of finding the diameter in the middle
between the head and bung diameters, is by putting the ga-
ging-rod CE into the bung at C, (when the axis A B is hori-
zontal;) let a ring be fixed at O, in the middle of CE,
t
o
8
through which the plumbline COP moves freely: in this
B
A
q
manner OP is determined, and is always greater than half
the diam ster in the middle between the head and bung; but
$
E
this diameter can be found when OP is known, thus:
m
Because OC=0E, and the triangles cot and .OE
are equiangular, Ot=08, or Af=fQ, or En =nm.
D
P
Em :: m 0; but Em is the double of En, consequently m C is the double of n O;
and as m C is known, n is also known.
But since n P (or and half the head diameter, are known, Pf half the middle di-
ameter is known, for
Let m D, half the difference between the head and bung diameters the bung diameter =
L=Af=fQ=En or n m, t the length of the cask; h=AE=fn or Qm half the head diameter;
P=0P, the length taken with the plumbline; and =fP, half the middle diameter.
Then 2 L: L : b-a 2 =0n; hence P = n P, and
2 = 2 h + b, the middle diameter sought.
Find the content of a cask, whose bung and head diameters and length are 36, 28, and 44 inches re-
spectively also the length taken with a plumb= 18.12 inches.
P=18.12
2P=1812 X 2= 8624
= (head diameter) = 2800
36- 28 = 400
.2P+ 2h +a=6824
and b = (bung diam.) = 36.00
32:24 = 2 x, the middle diameter.
Then we have the content = 1295697 gallons.
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CASTING AND FOUNDING.
239
Notwithstanding the apparent simplicity of this mode of finding the contents of casks, in practice it
becomes in some degree troublesome, and its accuracy depends much on the manner in which the dis-
tance 0 P is taken.
But if OP be obtained correctly, (at the same time observing that the cask lies level, that is, when
the axis A B is horizontal,) it approaches very near the truth.
If the cask be spheroidal, the content may be obtained by taking the length of a diagonal with a
rule commonly called Branan's, without having the head, bung, or length: apply the rule or rod from
the centre of the bung to where the end meets the stave at the opposite side-as from C to E in the
last figure; then the number on the rule in the centre of the bung will be the content in gallons.
The rule or diagonal rod here spoken of, is constructed for the middle frustum of a spheroid, there-
fore it will not give the true content unless the cask be of that particular form; and here it falls under
the objection that we have too many of the old methods, for we have no criterion whereby to judge
whether a cask is spheroidal or not.
Other diagonal rods can be constructed for casks of other varieties, as solids are to each other as the
cube of their like dimensions but these rods would be subject to the same objection as the one in use.
If the diagonal rod be applied to the head diameter of a cask, twice the diagonal number which
measures that diameter will be the content in gallons.
There are many other rules given in works on gaging besides those here treated of, several of them
depending on the construction of tables, such as the proportions of the bung dividea y the head diam-
eter, &c., but even before the introduction of the Patent SLIDING RULE and tape they were of very little
practical utility; we shall therefore refrain from giving them, and conclude with a general rule that may
be applied to casks promiscuously, without any respect to variety, and in all cases is a near approxi-
mation to the truth. It may be necessary to add, that the PATENT SLIDING RULE and TAPE were in-
vented by the editor, Mr. OLIVER BYRNE.
To 39 times the square of the bung diameter, add 25 times the square of the head diameter, and 26
times the product of the two diameters; then multiply the sum by the length, the product again by
000031473 will give the content in gallons; of 277-274 cubic inches each.
CAST-IRON, its manufacture. See MINERAL KINGDOM. Strength of various mixtures of, strength
of affected by mode of casting. See DETAILS OF ENGINES.
CASTINGS, how to make fine. See DETAILS OF ENGINES, and CASTING AND FOUNDING.
CASTING AND FOUNDING. We are indebted to the fusibility of the metals for the power of
giving them, with great facility and perfection, any required form, by pouring them, whilst in the fluid
state, into moulds of various kinds, of which the castings become, in general, the exact counterparts.
This property is of great value.
Some few objects are cast in open moulds, 80 that the upper surface of the fluid metal assumes the
horizontal position the same as other liquids, as in casting ingots, flat plates, and some few other ob-
jects; but in general the metals are cast in close moulds, 80 that it becomes necessary to provide one
or more apertures or ingates for pouring in the metal, and for allowing the escape of the air which
previously filled the moulds.
When these moulds are made of metal, they must be sufficiently hot not to chill or solidify the
fluid metal before it has time to adapt itself thoroughly to every part of the mould; and when the
moulds are made of earthy matters, although moisture is essential to their formation, little or none
should remain at the time they are filled.
The earthen moulds must be also sufficiently pervious to air, that any vapor or gases which may be
formed, either at the moment of pouring in the metal or during its solidification, may have free vent
to escape; otherwise, if these gases are rapidly formed, there is great danger of the metal being
driven out of the mould with a violent explosion, or when more slowly formed and locked up without
sufficient freedom for escape, the casting will be said to be blown, as some of the bubbles of air will
displace the fluid metal and render it spongy or porous. It not unfrequently happens that castings
which appear externally good and sound, are
full of hidden defects, because the surface
788.
being first cooled, the bubbles of air will at.
c
b
tempt to break their way through the cen-
tral and still soft parts of the casting.
The explanatory diagram, Fig. 788, is in-
tended to elucidate some of the circumstances
concerning the construction of moulds, which
in the greater number of cases are made only
B
in two parts, but in other cases are divided
into several. The figure to be moulded is
supposed to be a rod of elliptical section, the
d
mould for which might be divided into two
parts through the line A B, because no part
F
of the figure projects beyond the lines a b,
D
drawn from the margin of the model at right
angles to the line of division, and in which
direction the half of the mould would be removed or lifted; the model could be afterwards drawn out
from the second half of the mould in a similar manner.
The mould could be also parted upon the line D, because in that direction likewise, no part of the
model extends beyond the lines d, which show the direction in which the mould would be then lifted.
The mould, however complex, could be also parted either upon A B or upon CD, provided no part
of the model outstepped the rectangle formed by the dotted lines b c, or was undercut.
But, considering the figure 788 to be turned bottom upwards, and with the line EF horizontal, the
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CASTING AND FOUNDING.
removal of the entire half of the mould upon the lines e f would be impossible, because in raising the
mould perpendicularly to EF, that portion of the mould situated within the one perpendicular e, would
catch against the overhanging part of the oval towards A. Were the mould of metal, and therefore
rigid, it would be entirely locked fast, or it would not " deliver were the mould of sand, and there-
fore yielding, it would break and leave behind that part between A and E which caused the obstruc-
tion. Consequently, in such a case, the mould would be made with a small loose part between A and
E, so that when the principal portion, from A to F, had been lifted perpendicularly or in the direction
of the line e, the small undercut piece A to E might be withdrawn sidewise, on which account it would
be designated by the iron-founder a drawback, by the brass-founder a false core.
All the patterns in the mould, Fig. 789, could be extracted from each half of the mould, because
none of them encroach beyond the perpendicular line, or that in which the mould is lifted a and b
could be laid in exactly upon the diagonal, or upon one flat side, or partly imbedded; and in like man-
ner fg h might be sunk more or less into the mould, their sides being perpendicular; but the patterns
789.
d
c
b
a
790.
in Fig. 790 being undercut, the division of the mould into two parts only would be impracticable, and
false cores or subdivisions would be required in the manner represented, the construction of which will
be hereafter detailed.
Extending these same views to a more complex object, such as a bust, it will be conceived that
the mould must be divided into 80 many pieces, that none of them will be required to embrace any
795.
796.
792.
791.
t
t
b
b
s
794.
t
793.
c
s
6
overhanging part of the figure. For instance, were it attempted to mould a human head so that
the parting might pass through the central line of the face and down the back ; the two halves could
not be separated if they were made each in a single piece, as the inner angles of the eyes, the spaces
behind the ears, and the curls of the hair would obstruct it, and the head could be only thus moulded
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by making false cores or loose pieces at these particular places, in the manner illustrated by the
former figures. These would require to be accurately adapted to the surrounding parts by pins, or
contrivances to ensure their retaking their true positions. These remarks, however, are only advanced
by way of general illustration, as figure-casting is the most refined part of the art of moulding.
Metal moulds are employed for many works in the easily-fused metals, which are required to be
produced in large quantities, and with great similitude and economy the examination of which moulds
will serve to demonstrate many of the points of construction and proceeding. Thus the common
bullet-mould is made like a pair of pliers, the jaws of which are conjointly pierced with a hole or
passage leading into a spherical cavity; the aperture is equally divided between the two halves of the
mould, so that in fact the division is truly upon the diametrical line both of the sphere and the runner,
or the largest part of each; otherwise the pliers could not be opened to remove the bullet when cast.
Iron shot for great guns are likewise cast in iron moulds, by which they also possess great accuracy
of form and size.
Figs. 791 to 794 represent the moulds for casting pewter inkstands. These moulds are a little more
complex, and are each made in four parts; the black portions represent the sections of the inkstands
to be cast. The moulds each consist of a top-piece or cap t, a bottom or core b, and two sides or cottles
8 & In Fig. 794 the one side is removed, in order to expose the castings, and the top-piece t is supposed
to be sawn through to make the whole more distinct. It will be seen the top and bottom parts have
each a rebate like the lid of a snuffbox, which embrace the external edges of the two side-pieces 3 8,
and the latter divide, as in the bullet-mould, exactly upon the diametrical line of the inkstand, which in
a circular object is, of course, the largest part; the positions of the parts are therefore strictly main-
tained.
When the mould has been put together, laid upon its side, and filled through x the ingate, or as it is
technically called, the tedge, it is allowed to stand about a minute or two, and then the top t is knocked
off by one or two light blows of a pewter mallet; the mould is then held in the hand, and the bottom
part or core is knocked out of the casting by the edge; lastly, the two sides are pulled asunder by
their handles, and the casting is removed from the one in which it happens to stick fast; but it requires
cautious handling not to break it. The face of the mould is slightly coated with red ochre and white
of egg, to prevent the casting adhering to the saine, and to give the works a better face. The first few
castings are generally spoiled, until in fact the mould becomes properly warmed.
799.
798.
797.
P
3
a
800.
Most of the works made in the very useful material, pewter, are cast in gun-metal moulds, which re-
quire much skill in their construction thus, a pewter tankard, with a hinged cover and spout, consists
of six pieces, every one of which requires a different mould. Thus:-
1. The body has a mould in four parts, like that for the inkstand, but it is filled in the erect position
through two ingates, which are made through the top-piece t of the mould.
2. The bottom requires a mould in two parts, and is poured at the edge.
3. The cover is cast in the same manner; and thus far the moulds are all made in the lathe, in which
useful machine these castings are also finished before being soldered together.
4. The spout requires a mould in two parts.
5. The piece, Fig. 796, by which the cover is hinged to the handle, requires a much more complex
mould, which divides in four parts, as shown in Fig. 795, and much resembles, except in external form,
the remaining mould namely,
6. For the handle, which mould, like the last, consists of four pieces, fitted together with various ears
and projections. They are represented in their relative positions in Fig. 798, with the exception of the
piece a, Fig. 799, which is detached and shown bottom upwards. Fig. 797 shows the pewter handle
separately, with the three knuckles for joining on the cover; and on reference to Fig. 798, of the five
parts through which the pin p is thrust, the two external pieces belong respectively to the sides c and d
of the mould the others are parts of the casting, and the two hollows are formed by the two solid
knuckles fixed to the detached piece of the mould a, Fig. 799. At the time of pouring, the pin P serves
31
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CASTING AND FOUNDING.
to connect the three parts a c d together, and also to form the hole in the casting for the pin of the
joint.
Fig. 800 shows the section of the mould upon the dotted line & By this it will be seen the handle
is cast hollow, as almost immediately the mould has been filled through t, all but the thin external
shell is poured out again, and the weight is reduced to less than half. To extract the handle, the pin P
is first twisted out; then the joint-piece a is removed next the back-piece b; and lastly, the two sides
c d are pulled asunder.
Tin or pewter bearings for locomotive carriages have been cast in appropriate metal moulds and
such materials are very useful to the mechanist for many temporary purposes, such as collars, bearings,
screws, and nuts, either for difficult positions, or where no screw-tap is at hand and the resistance is
moderate; in such cases the parts of the machine constitute one portion of the mould, the apertures
being closed with moist loam. The processes are most successful when the parts can be made warm
and the clay is nearly dry.
The most important, exact, and interesting example of casting in metallic moulds is that of type-
founding, the description of which, as well as drawings of the mould, have been repeatedly given; some
of the peculiarities only of this art, will be therefore noticed. Each complete set of types consists of five
alphabets, A, A, a, A, a, besides many other characters, in all about two hundred, and which are re-
quired to be most strictly alike in every respect, except in device and width; the width is the greatest
for the W and M, and the least for the i and !. Every required measure of the types, (represented on
an enlarged scale in Fig. 801,) is determined by the mould alone, and not by any after correction.
TYPE-FOUNDING.
806.
801.
802
a
803.
8
c
a
804.
803.
If the moulds for the rectangular shafts of the types were made as in Figs. 802 or 803, the usual
forms of square moulds, they would not admit of alteration in width, as shifting a, Fig. 802, would pro-
duce no change, and Fig. 803 would thereby produce the form b. The mould which is used, is made in
two L-formed parts, as in Fig. 804; whence it follows that shifting the part a to the right or left, in-
creases or decreases the width of the type without interfering with its thickness, or as it is technically
called, its body, (B, Fig. 801 ;) the width, W, is adjusted by a piece called the register, fixed at the bottom
of the mould.
The device is changed by placing across the bottom of the mould one of the two hundred little pieces
of copper, Fig. 805, called matrices, into which the face of the letter is impressed by very beautifully-
formed punches. The length of the letter is determined by a contraction at the upper part of the
mould, as shown at c, Fig. 806, which represents the type as it leaves the mould the metal is poured
with a jerk, to make a sharp impression of the matrix,-the mould, which is held in the left hand, and
the ladle in the right, being jerked simultaneously upwards, at the moment of filling the mould, and
without which the face of the type would be rounded and quite imperfect. The breaks c, or the run-
ners of the types are first broken off, and after a slight correction of the sides, the hollows or channels
in the feet are planed out of a whole column of them, fixed between bars of wood, without touching the
square shoulders which determine the lengths of the types, and are left as originally cast.
In some types with a large face and much detail, such as the illustrations given above, the
motion of the hand is barely sufficient to give the momentum required to throw the metal into the
matrix, and produce a clean. sharp impression. A machine is then used, which may be compared to a
small forcing-pump, by which the mould is filled with the fluid metal; but from the greater difficulty
of allowing the air to escape, such types are in general considerably more unsound in the shaft or body
80 that an equal bulk of them only weigh about three-fourths as much as types cast in the ordinary
way by hand, and which for general purposes is preferable and more economical.
Some other variations are resorted to in type-founding; sometimes the mould is filled at twice, at
other times the faces of the types are dabbed, (the clichée process;) many of the large types and orna-
ments are stereotyped, and either soldered to metal bodies, or fixed by nails to those of wood. The
music type, and ornamental borders and dashes, display much very curious power of combination.
The clichée process is rather stamping than casting. The melted alloy is placed in a paper tray, and
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stirred with a card until it assumes the pasty condition. The metal die, or mould, is then "dabbed"
upon the soft metal, as in sealing a letter, but with a little more of sluggish force.
Plaster of Paris Moulds, and Sand Moulds.-Other examples of metallic moulds might be given,
but there are far more frequent cases in which one single casting is alone required; or else the number
is so small, or the pieces themselves are so large or peculiar, that the construction of metal moulds
would be found almost or quite impracticable, even without reference to an equally fatal barrier, the
expense.
In making these single copies in the metals of considerable fusibility, plaster of Paris is sometimes
employed: thus, after the printer has arranged the loose types into a page, and the requisite correc-
tions have been made, a stereotype, or solid type, is taken of the whole as a thin sheet of metal, which
serves to be printed from almost as well as the original letters; and its small cost enables the printer
to retain it for future use, after the types themselves have served perhaps for a hundred similar regen-
erations, and are ultimately worn out.
The stereotype-founder takes a copy of the entire mass of type in plaster of Paris; this is dried in
an oven, and placed face downwards within a cast-iron mould, like a covered box, open at the four top-
corners. The mould and plaster-cast are heated to the fusing temperature of the type-metal, and
gradually lowered into a pan or bath of the same by means of a crane; the hot fluid metal runs in at
the corners of the mould. and raises the inverted plaster, which latter would rise entirely to the surface
but for the restraint of the cover of the mould.
Type-metal is about eleven times as heavy as water; and if the mould be immersed four inches be-
low the surface, it is subjected to a pressure equal to that of a column of water forty-four inches high,
or of above two pounds upon every square inch.
The necessity of this arrangement is shown when a few ounces of type-metal are poured from a ladle
on the face of the plaster; the metal looks like a dump, almost without any mark of the letters, where-
as the stereotype-cast is nearly as sharp as the original type. The immersion fulfils the same end as
the jerk of the hand-caster, or of the pump occasionally employed; and the long continuance of the
mould in the fluid metal allows ample time for the air to escape in bubbles to the surface; after which
the mould is raised and cooled in a vessel of water, and the plaster is mostly destroyed in its removal.
Plaster of Paris, although it may be, and frequently is used for the fusible metals, such as lead, tin,
and pewter, cannot be employed alone for iron, copper, brass, and many other metals, the intense
melting heats of which would calcine the material, and cause it to crumble; even the soft metals should
not be very hot, or they will make the plaster of Paris blister off in flakes or dust. We must there-
fore seek a substitute better capable of enduring the heat, and likewise susceptible of receiving definite
forms; for which purpose damp sand, with a small natural or subsequent admixture of clay or loam, is
found to be perfectly adapted.
The moulding-sand cannot, however, be used without external support, and which is given by shal-
low iron frames, without tops or bottoms, called flasks, represented in Figs. 807 and 808. The bottom
part, 4, 5, is supposed to have been rammed full of sand, and to stand upon a flat board, 6. The model
of the plain flat bar which is to be cast, is now laid on the surface of the sand, that of the round bar is
imbedded half way in the same, and the mould is dusted with dry parting sand.
807.
808.
2
3
4
5
6
The top part of the flask 2, 3, is shown still empty, and in the act of being attached to 4, 5 by its
pins, which enter corresponding holes in the latter, easily but without shake: 2, 3 is also rammed full
of sand, and covered with a top board, 1, not represented to avoid confusion. The mould is now
opened, the models are removed, and channels are scooped out from the ends of the cavities left by the
models, to the hollows or pouring-holes at the end of the flask; the parts are all replaced in the order
1 to 6, represented in Fig. 808, and the whole are fixed together by screw-clamp3, 80 as to assume the
condition of Fig. 807.
The flask is now placed almost perpendicularly beside the pouring-trough, and the metal is poured
into it from the crucible; but the flask, if small, is put on the surface of the pouring or spill trough, and
propped up with a short bar.
This brief ketch of the entire process of moulding and casting in sand moulds, will be now followed
by some remarks in greater detail: first, on the patterns of the objects to be cast; secondly, on the
conditions required in the sand; and thirdly, the process of moulding simple and solid bodies. The
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CASTING AND FOUNDING.
section then following will be devoted to moulding cored works and figures, after which a few lines
will be given upon the subject of filling the moulds.
Patterns, Moulds, and moulding simple objects.-The perfection of castings depends much on the
skill of the pattern-maker, who should thoroughly understand the practice of the moulder, or he is
liable to make the patterns in such a manner that they cannot be used, or at any rate be well used.
Straight-grained deal, pine, and mahogany, are the best woods for making patterns, as they stand
the best: screws should be used in preference to nails, as alterations are then more easily made in the
models; and glue joints, such as dovetails, tenons, and dowels, are also good as regards the after use of
the saw and plane for corrections and alterations.
Foundry patterns should be always made a little taper in the parts which enter most deeply into the
sand, in order to assist their removal from the same, when their purposes will not be materially inter-
fered with by such tapering. The pattern-maker, therefore, works most of the thicknesses, and the
sides or edges, both internal and external, a little out of parallel or square-perhaps as much as about
one--ixteenth to one-eighth of an inch in the foot, sometimes much more.
When foundry patterns are exactly parallel, the friction of the sand against their sides is so great when
they penetrate deeply, that it requires considerable force to extract them; and which violence tears down
the sand, unless the patterns are much knocked about in the mould, to enlarge the space around them.
This rough usage frequently injures the patterns, and causes the castings to become irregularly larger
than intended, and also defective in point of shape, from the mischief sustained by the moulds; all
which evils are much lessened when the patterns are made consistently taper and very smooth.
It must be distinctly and constantly borne in mind, that although patterns require all the methods,
care, and skill, of good joinery or cabinet-making, they must not, like such works, be made quite square
and parallel, for the reasons stated. Sharp internal angles should in general be also avoided, as they
leave a sharp edge or arris in the sand, which is liable to be broken down in the removal of the pat-
tern, or to be washed down on the entry of the metal into the mould. Either the angle of the model
should be filled with wood, wax, or putty, or the sharp edges of the sand should be chamfered off with
the knife or trowel. Sharp internal angles are very injudicious in respect also to the strength of cast-
ings, as they seem to denote where they will be likely to break; and more resemble carpentry than
goo metallic construction.
Before the patterns reach the founder's hands, all the glue that may have been used in their con-
struction should be carefully scraped off, or it will adhere to and pull down the sand. The best way is
to paint or varnish wooden patterns, so as to prevent them from absorbing moisture, as they will then
hang to the sand much less, and will retain their forms much better. Whether painted or not, they
deliver more freely from the mould when they are well brushed with black-lead, like a stove.
In patterns made in the lathe, exactly the same conditions are required; the parts which enter
deeply into the sand should be neither exactly cylindrical nor plane surfaces, but either a little coned,
or rounding, as the case may be; and the internal angles should not be turned exactly to their ultimate
form, but rather filled in, or rounded, to save the breaking down of the sharp edges of the mould.
Foundry patterns are also made in metal; these are very excellent, as they are permanent and
when very small are less apt to be blown away by the bellows used for removing the loose sand and
dust from the moulds. To preserve iron patterns from rusting, and to make them deliver more easily,
they should be allowed to get slightly rusty, by lying one night on the damp sand next, they should
be warmed sufficiently to melt bees'-wax, which is then rubbed all over them, and in great part re-
moved. and then polished with a hard brush when cold. Wax is also used by the founder for stopping
up any little holes in the wooden patterns; whitening is likewise employed, as a quicker but less care-
ful expedient; and very rough patterns are seared with a hot iron. The good workman, however,
leaves no necessity for these corrections, and the perfection of the pattern is well repaid by the supe-
rior character of the castings.
Metal patterns frequently require to have holes tapped into them, for receiving screwed wires, by
way of h indles for lifting them out of the sand; and in like manner, large wooden patterns should have
screwed metal plates let into them for the same purpose, or the founder is compelled to drive pointed
wires into them, to serve as handles, which is an injurious practice.
The flasks or casting-boxes for containing the sand, are made of various sizes; each side is about 2 to
3 inches deep. They are poured at the edge when placed nearly vertical but for large brass works the
practice of the iron-founder is generally followed, who mostly pours his work horizontally, through a
hole in the top, as will be explained. The pins of the flask should fit easily but without shake, or the
two halves will -hift about and cause a disagreement or slip in the casting. The tools used in making
the moulds are few and simple; namely, a sieve, shovel, rammer, strike, mallet, a knife, and two or three
loo-ening wires and little trowels, which it is unnecessary to describe.
The principal materials for making foundry-moulds are very fine sand and loam they are found mixed
in various proportions, SO that the respective quantities proper for different uses cannot be well defined
but it is always judicious to employ the least quantity of loam that will suffice.* These materials are
seldom used in their new or recent states for brass castings, although more 80 for :ron; and the moulds
made of fre-h sand are always dried, as will be explained.
The ordinary moulds are made of the old damp sand, and they are generally poured immediately or
whilst they are green sometimes they are more or less dried upon the face. The old working sand is
con-iderably less adhesive than the new, and of a dark-brown color; this arises from the brickdust,
flour, and charcoal-dust, used in moulding, becoming mixed with the general stock, which therefore
requires occasional additions of new sand or loam, 80 that when slightly moist and pressed firmly in
the hand, it may form a moderately hard compact lump.
* The iron and brass founders' sand and loam used in this city are principally obtained from Long Island and are found
in great abundance in almost every state of the Union.
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Red brickdust is generally used to make the partings of the mould, or to prevent the damp sand in
the separate parts of the flask from adhering together.
The face of the mould which receives the metal, is generally dusted with meal-dust, or waste flour;
but in large works, powdered chalk, and also wood or tan ashes, are used, from being cheaper. The
moulds for the finest brass castings are faced either with charcoal, loamstone, rottenstone, or a mixture
of the same the moulds are frequently inverted and dried over a dull fire of cork shavings; or when
dried, they are smoked over pitch or black resin lighted in an iron ladle.*
The cores or loose internal parts of the moulds for forming holes and recesses, are made of various
proportions of new sand, loam, and horse-dung, as will be explained in treating of cored works.
They all require to be thoroughly dried, and those containing horse-dung must be well burned at a red
heat; this consumes the straw, and makes them porous and of a brick-red.
In making the various moulds, it becomes necessary to pursue a medium course between the conditions
best suited to the formation of the mould, and those best suited to filling them with the red-hot metal,
without risk of failure or accident. Thus, within certain limits, the more loam and moisture the sand
contains, and the more closely it is rammed, the better will be the impression of the model; but at the
same time, the moist and impervious condition of the mould would then incur the greater risk of acci-
dent, both from the moisture and from the non-escape of the air; therefore the policy, on the score of
safety, is to use the sand as dry as practicable, so as to avoid the delay of after-drying, and also to keep
the mould porous.
The founder, therefore, compromises the matter by using : little facing sand containing rather more
loam, for the face of the green moulds for general work; and in those cases where much loam is
used, the moulds are thoroughly dried by heat, which is not generally necessary with ordinary sand
moulds.
The power of conducting heat is considerably less in red-hot iron than in copper and brass, and there-
fore the moulds for the latter require to be in a drier condition than those which may be used for iron;
but in either case the presence of superfluous moisture is always attended with some danger to the
individual as well as to the work.t
Another point has also to be considered: as castings contract considerably in cooling, in moulding
large and slight works the face of the mould must not be too strongly rammed, nor too much dried, or
its strength may exceed that of the red-hot metal, whilst in the act of shrinking. The result would
be, that in contracting, the casting would be rent or torn asunder from the restraint of the mould
whereas it should have the preponderance of strength, 80 as to pull down the face of the sand instead
of being itself destroyed. But the exact condition both of the mould and of the melted metal, must
be determined by the nature of the object to be cast; matters which can be only referred to with the
development of the practice of the foundry, and upon which we shall now commence.
The sand having been prepared, and the appropriate flask and boards selected, the moulder first
examines every pattern separately, to determine the most appropriate way of inserting it in the flask,
as explained by Fig. 789; also to see that patterns, such as f and h, therein shown, are smallest at the
parts entering the most deeply into the sand, in order that they may deliver well. It should also be
noticed whether they are perfectly smooth, and that there is no glue hanging about them, which would
cause them to adhere and to pull down the moist sand.
The bottom flask, 4 and 5, Fig. 808, is placed on a board not less than an inch or two longer and wider than
itself, with the face 4 downwards, and it is filled from the side 5. A small portion of the strong facing-
sand is rubbed through a fine sieve; the remainder is thrown in from the trough with the shovel, and
the moulder drives the whole moderately hard into the flask, either with a mallet, the handle of the
spade, or other rammer; or else he jumps up by aid of the rope suspended from the ceiling, and treads
the sand in with his feet. The surface is then struck off level with a straight metal bar or scraper, a
little loose sand is sprinkled on the surface, upon which another board is placed, and rubbed down
close.
The two boards and the flask contained between them, are then all three turned over together; this
requires them to be brought to the front of the moulding-trough, so that the individual may rest his
chest against them, and his fore-arms upon the edges of the top board; he then grasps the three
together at the back part with his outstretched hands, and thus retained in contact, the whole are quickly
turned over upon the front edge of the moulding-trough, and then slid back upon the transverse bearers
or blocks, to the usual position.
The top board is afterwards taken off; the clean surface of moist sand, then exposed, is well dusted
over with red brickdust crushed fine, and contained in a linen bag; the mouth of the bag is held in the
right hand, and the bottom corner in the left, and both hands are shaken up and down together, to scatter
the dry powder uniformly over the flask; a part of the loose powder is removed with the hand-bellows,
and the bottom half of the mould is then ready for receiving the patterns.
The models are next arranged upon the face of the sand at 4, 80 as to leave space enough to prevent
the parts breaking one into the other, and also for the passages by which the metal is to be introduced,
and the air allowed to escape. When there are only two or three pieces to be cast, a separate runner
is often made to each of them from one of the holes in the end of the flask when several small patterns
are to be moulded, they are arranged on both sides a central runner, or ridge, from which small passages
The gold and silver casters frequently use a lighted link for facing their sand-moulds, and some of the type-founders'
metallic moulds are smoked over a lamp: all these modes deposite a fine layer of soot upon the moulds.
t The above is the reason generally assigned for the fact, that the iron-founders may and do use their moulds with safety
when sensibly more moist than is admissible for brass and copper castings. It is confirmatory of the fact, that the more
dense the mould, the drier it must be; as the sand used by iron-founders is also coarser and therefore more porous than
that employed by brass-founders.
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CASTING AND FOUNDING.
lead into every section of the mould. The whole mass when poured has been compared to a great fern-
leaf with its leaflets, and is usually called a spray.
Those patterns which are cylindrical or thick, are partly sunk in the sand, by scraping out hollow
recesses with the bowl of an old copper spoon, and knocking the model into the sand with a mallet;
afterwards the general surface is repaired to agreement with the diametrical line of the model, or its
largest section, as the case may be, by means of a knife or a little piece of sheet steel, something like
the worn-out blade of a dessert-knife bent up a little at the end, or else with very small trowels.
After the sand is made good to the edges of the patterns, the brickdust is again shaken over them,
so that the patterns may receive a slight share as well as the general surface of the sand. The upper
part of the flask 2, 3, is then fitted to the lower, or 4, 5, by the pins, and this half likewise is made up:
first a little strong sand is sifted in; it is then filled up from the trough, rammed down, and struck off
as before, the dry powder serving to prevent the two halves from sticking together.
In order to open the mould for the extraction of the models, a board is placed on the top of flask
2, 3, and struck smartly at different parts with the mallet; the tool is then laid aside, and the upper
part of the flask and its board are lifted up very gently and quite level; after which it is inverted on its
board, and now each of the inner faces of the mould is exposed. Should it happen that any considera-
ble portion of the mould, say a part as large as a cent, is broken down in one piece, the cavity is
moistened with the end of the knife, the mould is again carefully closed, and lightly struck before the
removal of the patterns; it is probable on the second lifting such piece will be picked up.
The breaks are carefully repaired before the extraction of the patterns, to effect which they are driven
slightly sidewise with blows of the mallet, given on a short wire or punch, 80 as to loosen them by
enlarging the space around them; the patterns are then lifted out very carefully with the finger-nails,
or sometimes a pointed wire is driven a little way into the pattern to serve as a handle to lift it by :*
this process requires some delicacy not to tear away the sand, which accident must be carefully re-
paired, sometimes by replacing the loose pieces, at other times with a little new sand picked out of any
unused part of the mould.
Should the flask only contain one or two objects, the ingate or runner is now scooped out of the sand,
80 as to lead from the object to the pouring-hole; and when several objects are contained, a large central
channel, and lesser passages sidewise, are made as before mentioned. The entrance round about the
pouring-hole is smoothed and compressed with the thumb, that it may not break down when the metal
is poured and all the loose sand is carefully blown out of the mould, both parts of which may be placed
edgewise for the more convenient application of the bellows, if necessary.
The succeeding processes are to dust the faces of both halves of the mould with meal-dust or waste
flour, as explained with regard to the brickdust, and to replace the mould and boards: the whole of
them are then carried to the spill-trough, upon the edge of which they are rested whilst the one board
is placed exactly level with the end of the flask; but the board on the side from which the crucible will
be poured, is placed about two inches below, as in Fig. 807, and the hand-screws are fixed on as shown.
The mould is now held mouth downwards, that any sand loosened in the screwing down may be allowed
to fall out, and the flask. according to its size, is supported either on the ground or on the surface of the
trough by aid of a little bar resting against the clamp: it is now quite ready to be filled, the particulars
of which process will be described when the remarks on moulding are concluded.
In works that require the first side, or 3, 4, to be cut away for imbedding the models, it is usual when
the second part, or 2, 3. has been made, to destroy the first or false side, (which is only hastily made,)
and to repeat it in a more careful manner by inverting the lower flask upon 2, 3, proceeding in all other
respects as before, by which means a much more accurate and sound mould is produced.
When many copies of the same patterns are required, an odd side is prepared; that is, a flask is
chosen to which there are two bottom sides, 4, 5. One of these latter is very carefully arranged with
all the patterns, but which are only imbedded barely half way, 80 that when 2, 3 is filled, and both are
turned over, the whole of the patterns are left in the new side; a second side, 4, 5, is moulded to serve
for receiving the metal, as the mould is destroyed every time the metal is poured in. By this plan the
trouble of rearranging the patterns for every separate mould is saved, as they are merely replaced in
the odd side, and the routine of forming the two working sides is repeated.
Moulding Cored Works.-If the objects to be cast require to be 80 moulded that when they leave the
sand they may contain one or several holes, they are said to be cored, and in such cases, a variety of
methods are practised for introducing internal moulds or cores, which shall intercept the flow of the
metal, and prevent it from forming one solid mass at those respective parts. For example, the pins
inserted in the pewterers' moulds, Figs. 795 and 798, for producing the holes in the joints, are essentially
cores. Various other methods are pursued, the three most usual of which are represented in Figs. 809,
810, and 811; the upper figures show the exact sections of the three models or casting patterns; the
lower figure represents the two halves of the mould, which are respectively shaded with perpendicular
and horizontal lines, the cores are shaded obliquely; and the white open spaces show the hollows to be
occupied by the metal when it is poured in.
First. Many works are said to deliver their own cores; of such kind is Fig. 809, in which the cavity
extends through the model, and exactly represents that which is required in the casting; the hole is
either made quite parallel, or a little larger one side than the other, and gradually taper between the
two. In some cases, when the hole is sufficiently taper, it delivers its own core as a continuation of the
general mass of sand filling the one side of the flask; but in many or most cases, the space in the model
is rammed full of strong sand at first, and it is then moulded as if to produce a plain solid casting.
Before the mould is finally closed for pouring, the sand core is pushed carefully out of the pattern, and
A steel ire, pointed and hardened, is convenient as a picker-out ; and when fixed in the pattern and struck sidewise,
it scrves as a loosening bar likewise.
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inserted in the mould; to denote its precise position, one side of the core is scored with one or two deep
marks in the first instance, which cause similar ridges or guides in the mould.
Secondly. When the hole extends only part way through, the hole of the pattern, Fig. 810, is fitted
with a solid plug, sawn and filed out of soft unburnt brick, principally sand, (or the common Flanders
brick; the core is made long enough to project about as much as its own diameter, and the work is
moulded as if to be cast with a solid pin, instead of a hole. The last step is to extract the filed core,
and to insert it into the hollow formed by itself in the flask.
811.
810.
809.
Thirdly. The patterns for iron-work and some others are mostly made with prints instead of holes,
as in Fig. 811; that is, the pattern-maker places square or round pieces on one or both sides of the
pattern, where the square or round holes are respectively required; and the founder has moulds for
forming cores of corresponding diameters or sections, and in lengths of about two to twelve inches,
short pieces of which are cut off as may be required.
For example, some core-boxes are made like Fig. 812, for cylindrical cores; these divide through the
axis, and are kept in position by pins; at the time when they are rammed they are fixed together by
wood or iron staples, embracing three sides of the mould, or else by screw-clamps. For straight cores,
say one inch wide, twelve inches long, and half-inch thick, the pieces of wood, Fig. 813, are also one inch
thick, with an opening between them of twelve inches long and half-inch wide. This core-box is laid
on a flat board; it is also held together with clamps, but without pins in the core-box, as the projection
at the one end gives the position; it is rammed flush with both sides, and the two parts can be then
separated obliquely. If it is preferred to make the cores to the precise lengths instead of cutting them
off, this core-box admits of contraction in length, in the manner of the type-mould, Fig. 804; and by
placing thin slips between the two halves it may be temporarily increased in width, but not in thick-
ness. Fig. 814 is a similar core-box for a casting with circular mortises; this requires either pins or
projections at each end, as it cannot be opened obliquely. Core-boxes are sometimes made of plaster
of Paris; wood is much better, and metal the best of all.
813.
812.
815.
814.
816.
817.
819.
Many works require core-boxes to be made expressly for them; thus the dotted line in Fig. 812
shows an enlargement in the centre for coring a hole of that particular section. Figs. 815 and 816
represent the two halves of a brass or lead core-box suitable to the stop-cock, Fig. 817; and Fig. 819
shows the core itself after its removal from the part 816, in which it is also figured. In 817, the model
from which the object is moulded, the shaded parts represent the projections, or core-prints, which
imprint within the mould the places where the extremities of the core, Fig. 819, are supported when
placed therein.
The various kinds of core-boxes are rammed full of new sand, sometimes with extra loam; the long
cores are strengthened by wires they are carefully removed from the boxes, and thoroughly dried
before use, in the oven prepared for the purpose.
Fig. 820 represents several examples of coring: in this view the works are represented of their ulti-
mate forms, that is, with the holes in them; in Fig. 821, the models are arranged in the flask, with the
runners all prepared, the prints of the cores being in every case shaded for distinction. Thus a is the
. Others prefer sand, horse-dung, and a very little loam, for making cores; these are dried, and then well burned, for
which purpose they are put into an empty crucible within the fire, the last thing at night, and allowed to remain until the
morning. This consumes the small particles of straw. and renders them more porous, in consequence of which the works
become sounder from the free escape of air, the necessity of which was adverted to in the earlier part of this subject, and can-
not be too much insisted upon.
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CASTING AND FOUNDING.
stop-cock, of which explanation has been already given; b has a straight and a circular mortise; this
pattern delivers its own core, in the manner referred to in Fig. 809, as the model is made with mortises
like the finished work: c only requires a perpendicular square core; d a round core parallel with the
face of the flask, and in this manner all tubes and sockets are cast, whether of uniform or irregular bore,
see Fig. 812; e has two rectangular cores crossing each other at right angles; and f is the cap of a
double-acting pump, the core for which is shown in section by the white part of Fig. 822, the shaded
portions being the metal; the great aperture leads to the piston, the two smaller are for valves opening
inwards and outwards; this of course requires a metal core-box capable of division in two parts, and
made exactly to the particular form.
820.
b
822.
€
d
c
821.
In addition to the cores used for making holes and mortises, much ingenious contrivance is displayed
in the cores employed for other works of every-day occurrence, the undercut parts of which WC uld
retain them in the sand but for the employment of these and analogous contrivances. It will now be
readily understood that if, in the Fig. 790, the parts shaded obliquely were separate, there would be no
difficulty in removing first the upper half of the flask, then the false cores, after which the patterns
would be quite free.* By such a method, however, the circular edge of a sheave would require at least
three such pieces; but Fig. 823 shows a different way of accomplishing the same thing, when the pattern
is made in two parts in the manner represented.
The entire model is first knocked into the side A, the sand is cut away to the inner margin of the
pattern which terminates upon the dotted line a, and the side A of the mould is then well dusted; a
layer of sand is now thrown on, and rammed tolerably firm to form an annular core, which is made
exactly level with the inner margin b of the pattern, and the core is well dusted; lastly, the side B is
put on and rammed as usual. To extract the model, the side B is first lifted, the half pattern b, b,
(which is shaded,) is removed, and the ingate is cut in the side B, to the edge of the pulley ; the mould
is well dusted with flour and replaced.
823.
B
8
8
b
a
a
The entire mould is now turned over A is first removed, then the remaining half pattern a, a, which
must be touched very tenderly or it will brenk down the core; and the runner (which divides in two
branches around the core) is also scooped out in the side A, which is dusted with flour and replaced,
ready for pouring. Common patterns not requiring cores, are frequently divided into two parts in the
above manner, so that when the mould is opened the pattern may divide and remain half in each side;
this lessens the risk of breaking down the mould and the attendant trouble of afterwards repairing it.
Reversing and Figure Casting.Supposing that an ornament, represented in section in Fig. 824,
has been modelled in relief, either in clay or wax upon a flat board, from which a thin casting in brass
is wanted without the tablet, the process is called reversing, and is to be accomplished in any of three
ways.
. The term false-core is employed by the brase-founder to express the same thing as the drawback of the iron-founder.
The former calls every loose piece of the mould not intended for holes, a false-core.
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First, an empty flask is placed upon the board, 824, and rammed full of sand; it assumes the
appearance of 825; the second part of the flask is attached to 825, and filled to make the part 826,
which is called the back-mould; some clay is then rolled out
to the intended thickness of the casting, with a cylindrical
roller running on two slips of wood or on two wires, and a
824.
narrow band of this clay is placed on 826, around the figure,
that it may separate 825 and 826, exactly to the required
distance, ready for receiving the metal.
By the second mode, 825 is first made, then 826, and from 825.
the latter 827 is moulded, which is a counterpart of 825. A
thin sheet of clay is then pressed all over 827, into every cavity,
and cut off flush with the plane surface of the mould, by which
it assumes the appearance denoted by the double line in 827.
After this 826 is destroyed, and made over again in 827, but 826.
80 much smaller than before as the thickness of the clay lining;
when the new back-mould 826 is placed in contact with 825,
it leaves the required space for the intended casting. This 827.
mode is only preferable to the first, when many parts of the
work are nearly perpendicular in which case, if the first
mode be adopted, a portion of the back-mould 825, must be pared away at the perpendicular parts,
and if incautiously performed there will be a risk of irregularity of thickness, or even of holes in the
casting.
The third mode, is to take a casting of 824 in plaster of Paris; when this is thoroughly dry it is oiled,
and poured full of a cement of wax, grease, and red ochre, which is poured out again when partially
set, leaving a thin crust behind, (as in the pewter handle.) A second, a third, or more layers of wax
are thus added until the whole is sufficiently thick, when the wax shell is extracted, and then moulded
from in the ordinary manner; the first brass casting is finished and chased to serve as the permanent
pattern. The management of the wax requires practice.
In constructing such moulds additional care is given to every part of the work; for example, the
sand is sifted much finer, the parting is made with fine charcoal dust, and the facing with charcoal and
rottenstone mixed together in about equal parts, the mixture being of a slaty color; sometimes the
loamstone, which is found in the pits where clay for making tiles is dug, is used instead of rottenstone.
The moulds are well dried in an oven, or over the mouth of the furnace, and the faces are afterwards
smoked over a dull fire of cork shavings; this deposites a very fine layer of soot over the face of the
mould, which greatly assists the running of the metal; when this additional care is taken the works are
known as fine-castings.
In casting figures, such as busts, animals, and ornaments consisting of branches and foliage, consider-
ably more skill is required the originals are generally solid, but the moulds necessarily divide into very
many parts. Most persons will have had the opportunity of judging of the complexity of these moulds,
from similar works in plaster of Paris, which are frequently purchased by artists and the virtuosi before
the seams of the mould are removed.
A glance at these plaster-casts, at the complex and undercut form of many of these ornamental works,
and at the explanatory diagram, Fig. 788, will convey some notion of the method to be pursued as well
as of the trouble attending them. It is shown, for example, by the diagram just referred to, that all
figured works approaching to the circular or elliptical section, require that the mould should be divided
into at least three parts, except under most favorable circumstances. In the human figure and quad-
rupeds, the four limbs and the trunk require at least three parts each, and often many more; it will be
easily conceived, therefore, that such moulded works require considerable skill and patience.
Piece after piece of the mould is successively produced, just as in making the core, Fig. 823, every
piece embracing only so much of the figure, as in no part to require any core to overhang the line in
which it is withdrawn. The side of the mould in which the figure is partly imbedded is first dusted
with charcoal, and then the first core is very carefully rammed into the nook, and pared down to the
new line of division; the green or wet sand-core is then dusted, and the second core is made, and after-
wards dusted, when the moulder proceeds with the third core, and so on; every one being carefully
adapted to its neighbor and withdrawn, to see that all is right, before the succeeding core is proceeded
with. The relative positions of the cores amongst themselves are readily recognised and maintained
by the irregularity of their forms, as in a child's dissected map, or by making a notch or two here and
there, which are faithfully copied in the succeeding piece. It is frequently necessary to thrust two or
more broken needles through the green cores into the neighboring parts to connect them together, in
imitation of the pins in the flasks.
All the parts of the mould are dried in the oven, and the facings are smoked over a cork fire as be-
fore explained; the perfection of the casting is augmented by pouring whilst the mould is still slightly
warm, as otherwise on cooling it has an increased affinity for damp; but the mould when hot is more or
less filled with aqueous vapor, which is equally prejudicial.
When a figure, such as a bust, is required to be cast hollow from a solid model, it is first moulded
exactly as above. The core is now produced as follows: At the foot of the bust a large space, nearly
equal in length and bulk to the bust, is cut away in the sand, to serve for fixing the core in the mould,
or for the balance, as it is called, as the core cannot be propped up at both ends. The entire hollow,
that is, for the bust and the balance, is filled with a composition of about one part of plaster of Paris
and two of sand or fine brickdust, mixed with a little water and poured in fluid, a few wires being
placed amidst the same for additional support.
The mould is now taken to pieces to extract the core, which is then dried, thoroughly burned, and
allowed to cool slowly, (which the founder calls annealing, from a similar method being employed in
32
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CASTING AND FOUNDING.
annealing or softening the metals and glass:) the core is then returned to the mould, to see that it has
not become distorted. If needful, the fitting around the balance is made good to suit the reduced
magnitude of the core, which latter is then so far pared away as to leave room for the thickness of
metal; this is frequently regulated by boring holes at many parts of the core with a stop-drill, having
a collar to prevent its penetrating beyond the determined depth; the surface of the core is now pared
down to the bottoms of the holes, as uniformly a3 possible. When the mould has been faced, dried,
and smoked, the whole is put together for pouring, for which purpose the figure is inverted and filled
from the pedestal.
Equestrian and other figures are sometimes cast in two, three, or more pieces, and joined together
by solder, screws, or wires; but in all such works the aim of the founder is to leave little or nothing for
the finisher or chaser to do.
Some objects which are either exceedingly complex in their form, or soft and flexible in their sub-
stance, and which do not therefore admit of being moulded in sand, in the ordinary manner of figure-
casting, may be moulded for a single copy, provided the originals consist of 8. bstances which may be
either readily melted or burned into ashes.
A cavity is made in the sand of the moulding-trough, a little larger and longer than the object, or
else a wooden box of appropriate size is procured, in the midst of which the wax model may be placed
to the end of the model is added a piece to represent the runner, which will be required for introducing
the metal. The composition of one-third plaster of Paris and two-thirds brickdust, mixed with water,
the same as for the core of the bust, is then poured in, entirely to surround the model. The mould is
first slowly dried; it is then inverted and made warm to allow the wax to run out, after which it is an-
nealed, or burned to redness; and lastly, when cooled, it is buried in sand and filled with metal. The
method necessarily throws the chance of success upon a single trial, as the model is destroyed.
Should the face of the casting be required to be particularly smooth, a small quantity of brickdust
is washed, (in the manner practised with emery, and to be explained,) and mixed with very fine plas-
ter a coat of this is brushed over the model, which excludes air-bubbles, the model is quickly placed in
its cavity, and the coarser mixture is poured in as before.
The above method exactly corroborates a mode long since described as being suitable to casting
copies of small animals or insects, parts of vegetables. and similar objects these are to be fixed in the
centre of a small box, by means of a few threads attached to any convenient parts, one or two wires
being added to make air-holes and ingates for the metal. A small quantity of river silt or mud, which
had been carefully washed, was first thrown in and spread around the object by swinging the box about;
and when partly dry, successive but coarser coats were thrown in. 80 as ultimately to fill up the box.
When it had become thoroughly dry, the wires were first removed from the earthy mould; it was then
burned to reduce the object to ashes, and when every particle of the model had been blown out, it was
ready to be filled with metal.
Filling the moulds.-Having traced the formation of various kinds of moulds for brass work, we must
now return to the furnace to see if the metal is in condition to be poured, which is indicated by the
slight wasting of the zinc from its surface with a lambent flame. When this condition is observed, the
large cokes are first removed from the mouth of the pot. and a long pair of crucible tongs are thrust
down beside the same to embrace it securely, after which a coupler is dropped upon the handles of the
tongs; the pot is now lifted out with both hands and carried to the skimming-place, where the loose
dross is skimmed off with an iron rod, and the pot is rested upon the spill-trough, against or upon which
the flasks are arranged.
The temperature at which the metal is poured must be proportioned to the magnitude of the works;
thus large, straggling, and thin castings, require the metal to be very hot, otherwise it will be chilled
from coming in contact with the extended surface of sand before having entirely filled the mould thick
massive castings if filled with such hot metal would be sand-burned, as the long continuance of the heat
would destroy the face of the mould before the metal would be solidified.
The line of policy seems therefore to be, to pour the metals at that period when they shall be suffi-
ciently fluid to fill the moulds perfectly and produce distinct and sharp impressions, but that the metal
shall become externally congealed as soon as possible afterwards.
For slight moulds the carbonaceous facings, whether meal-dust, charcoal, or soot, are good, as these
substances are bad conductors of heat, and rather aid than otherwise by their ignition; it is also proper
to air these moulds for thin works, or slightly warm them before a grate containing a coke fire. But in
massive works these precautions are less required, and the facing of common brickdust, which is in-
combustible and more binding, succeeds better.
The founder therefore fills the moulds having the slightest works first, and gradually proceeds to the
heaviest; if needful, he will wait a little to cool the metal, or will effect the same purpose by stirring
it with one of the ridges or waste runners, which thereby becomes partially melted. He judges of the
temperature of the melted brass principally by the eye. as when out of the furnace and very hot, the
surface emits a brilliant bluish white flame, and gives off clouds of the white oxide of zinc, a consid-
erable portion of which floats in the air like snow; the light decreases with the temperature, and but
little zinc is then fumed away.
Gun-metal and pot-metal, do not flare away in the manner of brass, the tin and lead being far less
volatile than zinc; neither should they be poured so hot or fluid as yellow brass, or they will become
sand-burned in a greater degree, or rather the tin and lead will strike to the surface. Gun-metal
and the much-used alloys of copper, tin, and zinc, are sometimes mixed at the time of pouring the
alloy of lead and copper is never so treated, but always contains old metal and copper is seldom
When the founder is in doubt as to the quality of the metal. from its containing old metal of unknown character, or
that he desires to be very exact, he will either pour a sample from the pot into an ingot mould, or extract a little with a
long rod terminating in a spoon heated to redness. The lump is cooled and tried with the file, saw, hammer, or drill, to
learn its quality.
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cast alone, but a trifling portion of zinc is added to it, otherwise the work becomes nearly full of little
air-bubbles throughout its surface.*
Some persons judge of the heat proper for pouring, by applying the skimmer to the surface of the
metal, which when very hot has a motion like that of boiling water; this dies away and becomes more
languid as the metal cools. Many works are spoiled from being poured too hot, and the management
of the heat is much more difficult when the quantity of metal is small.
The mixture and temperature of the metal being found to be proper, it is poured in the manner
represented in Fig. 788; the tongs are gradually lowered from the shoulder down the left arm, and the
right hand is employed in keeping back the dross from the lip of the melting-pot. A crucible contain-
ing the general quantity of 40 or 50 lbs. of metal, can be very conveniently managed by one individual;
but for larger quantities, sometimes amounting to one hundred weight, an assistant aids in supporting
the crucible, by catching hold of the shoulder of the tongs with a grunter, an iron rod bent like a
hook.
Whilst the mould is being filled, there is a rushing or hissing sound from the flow of the metal and
the escape of the air; the effect is less violent when there are two or more passages, as in heavy pieces,
and then the jet can be kept entirely full, which is desirable. Immediately after the mould is filled,
there are generally small but harmless explosions of the gases, which escape through the seams of the
mould they ignite from the runners, and burn quietly; but when the metal blows, from the after-escape
of any confined air, it makes a gurgling, bubbling noise, like the boiling of water, but much louder, and
it will sometimes throw the fluid metal out of the runner in three or four separate spirts. This effect,
which mostly spoils the castings, is much the most likely to occur with cored works, and with such an
are rammed injudiciously hard, without being, like the moulds for fine castings, subsequently well
dried.
The moulds are generally opened before the castings are cold, and the founder's duty is ended when
be has sawn off the ingates or ridges, and filed away the ragged edges where the metal has entered
the seams of the mould; small works are additionally cleaned in a rumble, or revolving cask, where
they soon scrub each other clean.
Nearly all small brass works are poured vertically, and the runners must be proportioned to the size
of the castings, that they may serve to fill the mould quickly. and supply at the top a mass of still fluid
metal, to serve as a head or pressure for compressing that which is beneath, to increase the density and
soundness of the casting. Most large works in brass, and the greater part of those in iron, are moulded
and poured horizontally, and the process being exactly alike for both metals, we must refer the reader
to the following.
Iron-Founders' Flasks, and Sand-moulds.-The process of moulding works in sand is essentially the
same both for brass and iron castings; but the very great magnitude of many of the latter give rise to
several differences in the methods it will suffice, however, to advert to the more important points in
which the two practices differ, or to those which have not been already noticed I shall therefore com-
mence with a few remarks upon the flasks and the sand.
In the greater number of cases, the iron-founder moulds and casts his works horizontally, with the
flasks lying upon the ground; frequently the top part only is lifted and in the largest works the
lower part of the flask is altogether omitted, such pieces being moulded in the sand constituting the
floor of the foundry; in these cases the position of the upper flask is denoted by driving a few iron
stakes into the earth, in contact with the internal angles of the lugs, or projecting ears of the flasks.
The sand would drop out of such large flasks, if only supported around the margin they are con-
sequently made with cross-bars, or wooden stays, a few inches asunder, which, unless the entire flask
is made of wood, are fixed by little fillets cast in the solid with the sides of the iron flasks. A great
number of hooks in the form of the letter S, but less crooked at the ends, are driven into the bars, and
both the bars and hooks are wetted with thick clay-water, 80 that the sand becomes entangled amidst
them, and is sustained when the flask is lifted. Some flasks require the force of either two or several
men, who raise them up by iron pins or handles projecting from the sides of the flask; they are then
placed upon one edge, and allowed to rest against any convenient support whilst they are repaired, or
they are sustained by a prop.
The very heavy flasks are lifted with the crane, by means of a transverse beam and two long hang-
ers, called clutches, which take hold of two gudgeons in the centres of the ends of the flask; it can be
then turned round in the slings, just the same as a dressing-glass, to enable it to be repaired.
The modern iron-founders' flasks are entirely of iron, and do not require the wooden stays, as
they are made full of cross-ribs nearly as deep as the flask itself, and which divide its entire surface
into compartments four or five inches wide, and one to two feet long. On the sides of every compart-
ment are little fillets, sloping opposite ways, so as to lock in the small bodies of sand very effectually.
When these top flasks are placed upon middle flasks without ribs, as in moulding thick objects, the
two parts are cottered or keyed together. by transverse wedges fixed in the steady pins of the flask;
lifters or gaggers are then placed amidst the sand these are light T-shaped pieces of iron, wetted and
placed head downwards, the tails of which are largest at top, so as to hold themselves in the sand, the
same as the keystone of an arch is supported. The gaggers are placed at various parts to combine
the sand in the two flasks, and they fulfil the same end as the iron hooks and nails driven into the
wooden stays of the old-fashioned flasks.
The bottom flask, or drag, has sometimes plain flat cross-ribs, two inches wide, (like a flat bottom
with square holes,) that it may be turned over without a bottom-board and unless the flasks have
swivels for the crane, they have two cast-iron pins at each end, and one or more large wrought-iron
handles at each side, by which they may be lifted and turned over by a proportionate number of men.
The engraved cylinders for calico-printing are required to be of pure copper, and their unsoundness when cast in the
usual way was found to be so serious an evil, that it gave rise, in 1819, to Holingrake's patent for casting the metals un-
der pressure.
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The sand of the iron-founder is coarser and less adhesive than that used by the brass-founder.
The parting-sand is the burned sand which is scraped off the castings it loses its sharp, crystalline
character from being exposed to the red heat. The facing-sand is sometimes only about equal parts of
coal-dust and charcoal-dust, ground very fine; at other times, either old or new sand is added, and for
large, thick works a little road-drift is introduced. All these substances get largely mixed with the sand
of the floor, and lessen its binding quality, which is compensated for by occasional additions of new
sand, and by using more moisture with the sand, as before extracting the patterns, the iron-founder
wets the edges of the sand with a sponge, which has sometimes a nail tied to it to direct the water
in a fine stream; for heavy works a watering-pot is used.
The green-sand moulds are made as in the brass-foundry, of the ordinary stock of old moist sand
these are often filled as soon as they have been made.
The dry-sand moulds are made in the same manner, but with new sand containing its full proportion
of loam; these moulds are thoroughly dried in a large oven or stove, and then blackwashed or painted,
with thin clay-water containing finely-ground charcoal; this facing is also thoroughly dried before the
moulds are poured.
The loam-moulds, which are much used for iron-castings, and somewhat also for those of brass, are
made of wet loam with a little sand, ground together in a mill to the consistence of mortar the moulds
are made partly after the manner of the bricklayer and plasterer, as will be explained; the loam moulds
also are thoroughly dried, blackwashed, and again dried, as from their greater compactness they allow
less efficient escape for the vapor or air, and therefore they must be put into the condition not to gener-
ate much vapor when they are filled.
Iron moulds are also employed for a small proportional number of works which are then called
chilled castings; and occasionally the methods of sand-casting and chilling are combined, as in some
axletree-boxes. which are moulded from wooden patterns in sand, and are cast upon an iron core. To
form the annular recess for oil, a ring of sand, made in an appropriate core-box, is slipped upon the iron
mandrel, and is left behind when the latter is driven out of the casting.
It would be a useless repetition to enter into the details of moulding ordinary iron-works; but from
the horizontal position of the flasks, it is necessary that the part of the work which is required to be
the soundest, and most free from defects, should be placed downwards, as the metal is more condensed
at the lower part, and free from the scoria or sullage which sometimes renders the upper surface very
rough and full of minute holes. As the flasks almost always lie on the ground, it is also found the
most convenient to retain them in contact by placing heavy weights upon them; the foundry should in
consequence have an abundant supply of these.
The flasks require to be poured through a hole in the upper half, as seen at r, Fig. 837, which hole is
formed by placing a wooden runner-stick in the top part A, whilst it is being rammed and a small
channel is afterwards cut sidewise into the mould. Sometimes two, three, or even half-a-dozen or more
runners are put to one single casting, either when it requires a great weight of metal, or when it is large
but slight, as in trellis-work, in which case the metal might cool before filling the mould, if only intro-
duced at one single runner.
When the runners are required to be lofty, either to supply pressure to the metal, or as a reserve
to fill up the space left by its contraction in cooling, iron rings of six or eight inches diameter are piled
up to the required height, to support the tube of sand contained within them. Small objects that are
poured from one hole, are frequently moulded with two runners, that the metal may flow through
the mould, and that there may be a sufficient supply to meet the shrinkage, and also to supply
head or pressure; another advantage also results, as it assists in carrying off the scoria or sullage.
The iron-founder employs all the methods of coring explained at pages 246 to 248, and also others
of an entirely different kind but little required in brass-works; namely, for lateral holes in the parts
of the castings buried beneath the general surface of the mould, and which are explained by the
Figs. 828 to 831. Thus, 828 represents the finished casting, 829 the model of the same, 830 the ap-
pearance of the bottom flask or drag when the pattern is first removed, and 831 the flask and cores
when closed ready for pouring; the moulds are inverted, and the same letters of reference refer to
similar parts of all these figures.
831.
830.
820.
828.
a
3
a
d
3
a
a
The core-print a would deliver from the sand, and leave the cavity at a, Fig. 830, to be afterwards
filled by the core shown in Fig. 831, the same as formerly explained at Fig. 811. But the core-print
b, Fig. 829, (which has reference to the stud b, Fig. 831,) would tear away the sand above it in with-
drawing the pattern therefore the print b should, like d, Fig. 829, extend to the face of the pattern, or
the parting line, represented by e, Fig. 831. This being the case, the pattern would leave the space
denoted at d, Fig. 830; the core is put down sidewise to the bottom of the recess, and extends entirely
across the same the small open space above is made good with the general surface, as shown by the
shade lines in Fig. 831, and this filling in, at the same time fixes the core precisely where denoted by
the print d, which latter has a mark to show to the moulder where the core is to end. The circular
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hole requires the core-print shown at c, Fig. 829 the cores themselves are made in the core-boxes,
812 and 813, before explained.
Fig. 832 represents the model and core-print, from which the finished casting shown at Fig. 832 might
be made from a solid pattern in a two-part flask; it would be inverted, and the parting would be made
832.
833.
x
a
a
upon the line x. The prints for the four holes a a, would be placed in the top flask, and those for the
great apertures or panels d, would be made in a core-box of the express form, and as thick as the pat-
tern and core-print measured together. The core would be deposited edgewise into the core-print, and
the upper corners of the mould will be made good, as explained in Fig. 831.
By the same method, a mortise-wheel, or one with spaces around its edge, as at m m, Fig. 833, to be
filled with wooden cogs, might be made with a series of core-prints, as at c, brought up flush with the
parting of the mould; if every print were filled with a core such as Fig. 833, made in an appropriate
core-box, the matter would be accomplished with great facility and truth.
The iron-founder makes frequent use of flasks which divide in three or four parts; this is done in
many cases simply to increase the depth of the contained space in which case, when wooden flasks
were employed, they admitted of being temporarily fixed together by dogs, or large iron staples, driven
a little way into the neighboring flasks, but the modern iron flasks are fixed by cotters. The following
examples will show the nature of some other uses to which the flasks with several partings are applied.
835.
c
834.
1
1
B
2
2
A
'
A casting, such as Fig. 834, which represents the top of a sliding-rest for a lathe, might be moulded
in a very deep two-part flask, if the parting were made upon the dotted line a a; but there would be
very great risk of tearing down the mould in drawing out the pattern and from the depth, there would
be scarcely a po-sibility of repairing it, and the metal would probably be strained. It would be also
possible to mould it with the joining upon the line b, provided several cores were employed; but the
mode adopted is more convenient than either of these, when the pattern is made in two parts, and
the flask in three, as in Fig. 835.
A and B are first united and partly filled with sand, the pattern is knocked in as represented, and the
whole well rammed, especially in the groove, the parting being made on the line 11, and dusted. C is
now put on, filled, and struck off level; a board is put above it, and ABC are all turned over together,
A becoming the top.
A is now removed, and the sand is cut away to make the second parting on the line 22, after which
A is replaced, and the runner-stick is inserted to make the runner r. On removing the pattern, the
runner-stick r is first taken out, A, or the top part of the flask, is lifted off, and the white part of the
pattern is drawn out; B. or the middle part, is then lifted, and the last or shaded piece of the pattern
is drawn out of the mould, which is now put together again, and poured through r; 80 that the top-
surface of the pattern, as seen in both views, becomes the face, from being cast downwards, or upon
the lowest piece C, of the flask, called the drag.
The part c, Fig. 834, might be cast with a chamfer in three different ways; although, in small cast-
ings, it is more usual to cast it square and plane it out of the solid. First, the pattern might be moulded
square, and the top A, after removal, might be worked to the angle by aid of the trowel and a cham-
fered slip of wood, used as a gage; or secondly, by the employment of a core, the print of which is
represented by the dotted lines terminating at the angle d, Fig. 834; or thirdly, by having a loose
slip on the pattern sliding on the line c, Fig. 834, so as to be drawn off when the top A had been lifted.
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CASTING AND FOUNDING.
This last method is analogous to that represented in Fig. 836, also intended for a sliding-rest, and which
might be cast in a two-part flask, if the two chamfers cc were fitted loosely upon slides, as shown; but
a three-part flask is more convenient, as explained by Fig. 837, in which the pattern is inverted.
837.
836.
m
m
2
2
B
1
1
c
m
The lowest piece C, or the drag, is parted upon the line 11, but its sand extends upwards between
the two sides of the pattern, as shown by the shade lines. The middle piece B is parted through the
line 22; and lastly A, the top, is filled up level, the runner-stick at r being inserted at the time; A is
first lifted, and all the pattern is then removed, excepting the chamfered bars and their slides, which
are represented black this pattern delivers its own cores for the circular mortises m m, the sand form-
ing them being a part of that in B, or the middle flask; lastly, B is lifted, and the chamfer-slips are
picked off from C. This pattern may consequently be moulded without turning over the flask, and
every part of the mould is quite accessible for repair.
The pedestal of the swage-block, is another good example of moulding in a three-part flask.
The model is made with the upper fillet loose, also with the sides solid, or without the holes, and
the object is moulded as it stands. The top part of the flask opens at the upper moulding, and
which latter is then removed from the pattern; the middle flask divides at the plinth or flange, so
that when this has been lifted, the pattern also may be withdrawn, leaving a square pedestal of sand,
as large as the interior of the model, standing upon the bottom part or drag, as in Fig. 837. The panels
are made by means of a core-box, of the kind Fig. 814: the box is exactly as thick as the metal to be
cast; and the circular cores are then fixed upon the pedestal of sand by means of a few wires or nails,
after which the flask is put together: ready for pouring.
If the casting here referred to, had four fluted columns at the four angles, either with a large cap to
each, or with a square entablature connecting the whole of them, the object might be also cast in one
piece, if moulded in a three-part flask. After removing the top flask, the entablature and capitals
would be first withdrawn, the columns being divided through their smallest diameters the mould
would be then turned over, and upon lifting off the drag, or bottom piece, the remainder of the pattern
could be drawn, either in one single piece, or if the pillars were loose, the five parts could be more
safely extracted the three-part mould would be put together again, and reversed for pouring. In this
general manner, by making either the mould or the pattern, or both, in different pieces, and by the
judicious employment of cores and drawbacks, objects apparently the most untractable are cast with
very great perfection.
The iron-founders are likewise very dexterous in making castings in some respects different from
the patterns from which they are moulded thus, if the pattern be too long, or that it be temporarily
desired to obliterate some few parts, the mould is made of the full size and stopped-off, additional sand
being worked into the mould, by aid of the trowel and some temporary piece of wood, to represent
the imagined termination of the pattern. On the other hand, any simple enlargement or addition is
not always added to the pattern, but it is frequently cut out of the mould with the trowel, in a similar
manner.
Many common works, such as plates. gratings, parts of ordinary stoves, and simple objects, are made
to written measures, and without pattern3, as a few parallel slips of wood to represent the margin of
the casting are arranged for the purpose upon a flat body of sand, which is modelled up almost entirely
by hand but for all accurate purposes and for machinery, good and well-made patterns are indispen-
sable, and to some particulars of which a little attention will be now devoted.
Remarks on Patterns for Iron Castings.-The construction of patterns for iron castings requires not
only the observance of all the particulars conveyed, but in addition, the large size of the models, the
peculiar methods employed in moulding them, and the nearly inflexible nature of the iron castings
when produced, call for some other and important considerations; and which should not be entirely
overlooked. even in works of comparatively small size. or it may lead to failure and disappointment.
Thus, it becomes necessary to make patterns in some degree larger than the intended iron castings,
to allow for their contraction in cooling, which equals from about the ninety-fifth to the ninety-eighth
part of their length, or nearly one per cent. This allowance is very easily and correctly managed by
the employment of a contraction-ru'e, which is made like a surveyor's rod, but one-eighth of an inch
longer in every foot than ordinary standard measure. By the employment of such contraction-rules,
every measurement of the pattern is made proportionally larger without any trouble of calculation.
When a wood pattern is made, from which an iron pattern is to be cast. the latter being intended to
serve as the permanent foundry pattern, as there are two shrinkages to allow for, a double contraction-
rule is employed, or one the length of which is one quarter of an inch in excess in every foot. These
rules are particularly important in setting out alterations in, or additions to, existing machinery the
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latter is measured with the common rule, and the new patterns are set out, to the same nominal
measures, with a single or double contraction-rule as the case may be, the three being made in some re-
spects dissimilar to avoid confusion in their use the entire neglect of contraction-rules incurs ad-
ditional trouble and uncertainty.*
Patterns for iron castings are much more frequently divided into several parts than those for brass;
for instance, the division into two equal parts, after the manner of Fig. 823, (but without reference to
the under-cutting,) is very common, as both the pattern and flask separate when the top part is lifted,
and the halves of the pattern can then be drawn out from the halves of the flask with much less risk
of tearing down the sand.
Fig. 790, if small, would be moulded as represented, with false cores or drawbacks; but if it were
a large fluted column, the iron-founder would employ a solid two-part flask; the shaded parts would
together represent the body of sand in the drag, and the pattern would be made in three parts,
something like a boot-tree. When the top flask had been lifted, the central slice of the pattern, ex-
tending from the two upper to the two lower angles, would be withdrawn vertically, and the two outer
pieces would be released sidewise. The general rule is to divide the circumference of the pattern
into six equal parts, and to let the central slice equal one of them in width.
The figures 835 and 837, representing two parts of a slide-rest, and the pedestal, are some
amongst many of the common examples of the division of the patterns; and with which may be asso-
ciated the numerous subdivisions of the mould instead of the pattern, by the employment of cores,
many applications of which have been also explained. All these matters display much interesting and
ingenious contrivance, resorted to either to render possible the operation of moulding, or to facilitate its
performance.
To lessen the distortion of castings from their unequal contraction in cooling, it is important that
the models should be nearly symmetrical. For example, bars or rods of all the sections in Fig. 789
may be expected to remain straight; perhaps g is the most uncertain, but if the lower fins of 6 and h
were removed, their flat surfaces then exposed to the sand would become rounding or convex in length,
from the contraction of the upper rib being unopposed by that of a similar piece on the under side.
Bars and beams, the sections of which resemble the letter I, are of the most favorable kind for general
permanence, and also for strength, and large panels may be cut out from their central plates to diminish
their weight without materially reducing their stability. They are much used, not only in building,
but also in the framing of machinery, which is in a great measure based upon the same general rules.
It is also of great importance, especially in castings of large size, that the thickness of the metal
should be nearly alike throughout, 80 that it may cool at all parts in about the same time. Should it
happen that one part is set or rigid, whilst another is semi-fluid, or in the act of crystallizing, there is
great risk of the one part being altogether torn from the other and producing fracture. Or should the
disturbing force be insufficient to break the casting, it may strain the metal nearly to its limit of tenacity
or elasticity; so that a force far below that which the casting should properly bear may break it in
pieces.
An example of this is seen in wheels with very light arms and heavy rims or bosses. The arms
sometimes cool so quickly as to tear themselves away from the still hot rim or nave or when the arms
are solidified without fracture, the contraction of the rim may so compress the spokes endwise as to
dish the wheel, (in the manner of an ordinary carriage-wheel,) and thereby strain the casting nearly or
quite to the point of fracture. The arms are sometimes curved like the letter s, instead of being
straight and radial; the contraction then increases their curvature with less risk of accident than to
straight arms.t A more elegant way of avoiding the mischief was invented by Mr. Isaac Dodd, of
the Horsley Iron Works, by placing the spokes as tangents to the central boss, in which case the con-
traction of the rim makes a small angular change of position in the boss for the rim in thrusting the
spokes inwards, causes the boss to twist round a little way with far less risk of fracture.
The destructive irregularity of thick and thin works is partly averted by uncovering the thick parts
of the casting, or even cooling them still more hastily, by throwing on water from watering-pots. In
wheels this has been done by a hose, the axis of which is concentric with the wheel, the arms being all
the time surrounded by the sand to retard their cooling; but it is the most judicious in all patterns, to
make the substance for the metal as nearly uniform throughout as circumstances will admit, so as not
to require these modes of partial treatment, which often compromise the ultimate strength of the
casting.
Another mode sometimes adopted for avoiding the fracture of wheels, from the great dissimilarity
of their proportions, is by inserting wrought-iron arms in the mould, but they do not always unite
indly with the iron of the rim and the nave. The same inconvenience occurs when iron pins are in-
serted in the ends of either iron or brass castings, to serve for their attachment to their respective
places. In iron castings it frequently produces the effect of chill casting, 80 as to render the works
difficult to be turned or filed at the junction, and there is risk of the casting becoming blown or un-
The contraction of brass is nearly three-sixteenths of an inch in every foot, but from the small size of brass castings
the contraction-rule is less required for them, as the differences may be easily allowed for without it.
Iron castings weigh about fourteen times as much as the ordinary deal and fir patterns from which they are made, that
being nearly the ratio of the specific gravities of those materials. All these matters are entered into in the pam-
phiet, A New System of Scales of Equal Parts," and the paper On a Scale of Geometrical Equivalents for Engineer-
Ing and other Purposes," Lond. and Edin. Philos. Mag., July, 1838, wherein are described numerous applications of scales
of equal parts to the purposes of drawing and calculation, and to the comparison and conversion of all kinds of measures,
weights, and other quantities.
t It appears to be often desirable to supersede the straight diagonal braces of iron castings by curved lines, which are
both more ornamental, and better disposed to yield to compression or extension by a slight alteration in their curvature.
1 Mr. Dodd had to contend with the shrinking of the nave, which was the last to cool the accidents therefore occurred
from the tension. instead of the compression of the spokes; this equally fatal effect was completely remedied by placing
the arms as tangents.-Trans. Soc. of Arts, vol. li. p. 66.
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CASTING AND FOUNDING.
sound in either case. When the pins are heated before being placed in the mould, they become nearly
cold before the metal can be poured, and they also endanger the presence of a little steam or vapor,
which is detrimental; therefore they are more generally put in cold, notwithstanding the sudden check
they then give to the fluid metal.
The patterns for iron castings of large size are necessarily very expensive, especially those for hol-
low cylinders and pans, many of which are 80 large that it would be impossible to find solid pieces of
wood from which the patterns could be made; either with sufficient strength for present use, or with
the necessary permanence or form for a subsequent period, as they would be almost sure either to
break, or to become distorted from the effects of unequal shrinking. Such patterns, therefore, require
to be made of a great many thin layers or rings of wood, each consisting of 6, 8, or 12 pieces, like the
felloes of wheels, 80 that in all parts the grain may be nearly in the direction of a tangent.
As they are glued up, every succeeding layer is connected with the former, by glue and wooden pins
or dowels, and the whole is afterwards turned to the tubular or hemispherical form, as the case may
be. As the castings are generally required to be rather thin, such models are not only very expensive,
but also very liable to accident; and besides, it frequently occurs that only one or two castings of a
kind may be required, which makes the proportional cost of the patterns excessive.
It fortunately happens, however, that this case, which is one of the most costly and uncertain by the
employment of ordinary wood or metal patterns, becomes exceedingly manageable by a peculiar and
simple application of the art of turning, (the one great centre of the constructive arts, to which these
pages are intended immediately and collaterally to apply;) and by which process, or one branch of
loam moulding, to be explained in the following section, patterns are not generally required.
Loam Moulding.-Figs. 838, 839, and 840, are intended to illustrate this process as regards a steam
cylinder. Fig. 838 is the entire section of the mould in its first stage; Figs. 839 and 840 are the half
sections of the second and third stages, preparatory to burying the mould in the pit in which it is to be
filled.
The inner part of the loam-mould is called the core when small, but the nowel when large; the outer
is called the case or the cope. Each part is built upon an iron loam-plate, or a ring cast rough on the
face, and with four ears by which it may be lifted. The mould is occasionally erected upon four shal-
low pedestals of bricks for the convenience of making a fire beneath it to dry the loam; at other times
it is made upon a low truck upon which it may be wheeled into the loam-stove, which is heated to
about the temperature of 300 to 400 degrees Fahrenheit.
A vertical axis a, is mounted in any convenient manner, frequently in two holes in the truck itself, or
as shown in Fig. 838, in a pedestal or socket erected upon the truck; at other times the axis is mounted
in a hole in the loam-plate, and in any bearing attached either to the building, or its roof.
840.
839.
838.
a
8
c
a
o
c
b
The first step is to fix upon the spindle the templet b b, at the distance of the radius of the cylinder,
either by one or two clutches, with various binding screws. An inner cylinder of brickwork is then
built up, plastered by the hands with soft loam, (which is represented black in all the figures,) and
scraped into the cylindrical form by the radius board, which is moved round on its axis by a boy.
When the surface is smooth and fair it is thoroughly dried, after which it is brushed over with black-
wash, and again dried. The charcoal-dust in the blackwash serves as a parting, to prevent the sue-
ceeding portions of the loam-mould from adhering to the first.
The templet c c, Fig. 839, cut exactly to the external form of the cylinder, is now attached to the
axis at the distance from the core required for the thickness of the metal some additional loam is
thrown on to form the thickness, which is smoothed in the same careful manner as the centre, after
which the templet and spindle are dismounted, and the thickness, which is represented white in Figs.
839 and 840, is also dried and blackwashed.
The ring for the outer case or cope is now laid down, and its position is denoted either by fixed studs
or by marks; and the outer case represented in Fig. 840, is built up of bricks and loam, with an inner
facing of loam worked very accurately to the turned thickness. The new work or the cope is also
thoroughly dried, and afterwards lifted off very carefully by means of the crane and a cross-beam with
four chains. This process likewise drags off the thickness, which usually breaks in the removal; its
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remains are carefully picked out of the cope, both parts of the mould are repaired, and again black-
washed and dried.
When the cylinder requires ports at the ends, or the short tubes with flanges for attaching the steam
passages, models of the tubes are worked into the cope, and are afterwards withdrawn; the cores are
made in core-boxes, and are partly supported by the outer extremity, and partly upon grains, or two
little plates of sheet-iron connected by a central wire, the whole being equal to the thickness of the
metal at the part. When steam passages are wanted, either along the side, or around the cylinder
they are worked up in clay upon the thickness, and duly covered in by the cope; their cores are sup-
ported, partly by their loose ends, and partly by grains, which become entirely surrounded by, and fixed
in the metal, when it is poured.*
The mould is now put together in a pit sunk in the floor of the foundry, and the two iron plates are
screwed together; the surrounding space being rammed hard to prevent the mould from bursting open,
but the inner part is left much more loose for the escape of the air. The top edges of the mould are
covered over with a loam-cake, (which has been previously made and dried,) or a ring three or four
inches thick, strengthened with iron bars amidst the clay, the joining being made air-tight by a little
cow's hair, and by the pressure of a quantity of iron weights; the loam-cake is generally perforated
with many holes, as shown at d, for the entry of the metal and the escape of the air. But provision
must always be made in casting thin cylinders, boxes, and such like forms, for the breaking up of the
core as soon as the metal is set, to prevent the metal scoring or rending from its contraction upon a
rigid, unyielding centre.4
Large pans, and various other circular works, are moulded precisely in the same way as cylinders,
except that curved templets are used, and that towards the conclusion, the apertures through which the
spindle passed are filled in and worked by hand to the general surface.
Water-pipes are made much in the same mode, but the cores for these are turned upon an iron tube
pierced full of holes, which is laid horizontally across two iron trestles with notches, and is kept in rota-
tion by a winch-handle at the end; there is also a shaper-board or scraper fixed parallel with the axis:
this primitive apparatus is called a founder's lathe.
The perforated tube (serving as the mandrel) is first wound round with haybands, then covered
with loam, and the core is turned, dried, and blackwashed; the thickness is now laid on and also black-
washed, after which the object is moulded in sand. The thickness is next removed from the core,
which latter is inserted in the mould, and supported therein by the two prints at the extremities, and
by grains with long wires, the positions of which may be seen by the little bosses on the pipe, the
metal being there made purposely thicker to avoid any accidental leakage at those parts. When
pipes are cast in large quantities, they are moulded from wooden patterns in halves, so that it only
becomes necessary to turn the core; and this, when made in the above manner, is sufficiently porous for
the escape of the air.
The moulds for crooked pipes and branches are frequently made in halves, upon a flat iron plate.
An iron bar or templet of the curve required is fixed down, and a semicircular piece of wood, called a
strickle, is used for working and smoothing the half core; next a larger strickle is used for laying on
the thickness, the two halves are then fixed together by wires, and moulded from in the sand-flask; the
thickness is now stripped off the core, which is fixed in the mould by its extremities, and if needful, is
supported also upon grains.
By the employment of these means, although the loam-work requires time for the drying, yet with
ordinary care an equality of thickness may be maintained, notwithstanding the complexity of the out-
line, and without the necessity for wooden patterns.
Very many of the large works in brass are also moulded in loam, the management being in most
respects exactly the same as for iron, except that in some ornamental works wax is more or less em-
ployed, and is melted out of the moulds before the entry of the metal; a very slight view of the
methods will serve as a sequel to the subject of brass-founding.
Large bells are turned in almost the same manner as iron cylinders or pans, by means of wooden
templets, edged with metal, and shaped to the inner and outer contour of the core and thickness. The
inscription and ornaments are either impressed within the cope, the clay of which is partially softened
for the purpose, or the ornaments are moulded in wax, and fixed on the clay thickness before making
the cope. Less generally the whole exterior face of the bell, or indeed its entire substance, is modelled
in wax, and melted out before pouring. In any case, the concluding steps in filling up the apertures
where the spindle passed, are to attach a dissected wooden pattern of the central stem and of the six
cannons or ears by which the bell is slung, which parts are moulded in soft loam; and then, the parts
There is always some uncertainty of the sound union of the grains, or other pieces of iron, with the cast-metal. Some
cast them in iron and file them quite bright; others also tin them, apparently to preserve them from rust, as the tin must
be instantly dissipated by the hot metal. Grains should always present clean metallic surfaces, and when used for very
thin castings, to prevent them from dropping out, the wires are nicked with a file that they may be keyed in the metal. It
is, however, better to avoid the use of grains, which may be generally done by giving the core sand bearings, and after-
wards plugging up the holes in the casting.
+ The largest cylinders, such as those of the Cornish pumping-engines, of 80, 90, and 95 inches bore, and 12 or 14 feet in
length, and the blowing cylinders of blast furnaces, sometimes 105 inches bore, are made without the employment of the
thickness. The case or cope is built up in the pit, and turned inside, with a radius bar, and the core is erected on a plate
on the floor, and turned outside to a gage; when dried, it is lowered into the other by the crane. The cylinders are cast one
foot or upwards longer than required, to serve as a head of metal and make the top edge sound, and thus much is cut off
before they are bored.
To enable the mould to resist the great pressure of the lofty column of fluid metal. (equal at the base to near 60 pounds
on every square inch,) the core is strengthened by diametrical iron bars entering slightly into the brickwork: the outer
cylinder is surrounded at a small distance by iron rings piled one on the other, the Interval being rammed with sand; and
stays are placed in all directions from the rings to the sides of the pit. which is either lined with brickwork, or when liable
to be inundated with water, it is made of Iron like a water-tight caisson.
Small cylinders are moulded in sand from wooden models, and only the cores are turned in loam; for cylinders of the
smallest size the cores are made of sand in core-boxes, as already explained.
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CASTING AND FOUNDING.
having been dried and replaced, and the iron ring for the clapper inserted, the whole is ready for the
pouring-pit. The heaviest bells are moulded within the pit the same as huge cylinders.
Brass guns are also moulded in loam, and in a somewhat peculiar manner; a taper rod of wood, much
longer than the gun, is wound round with a peculiar kind of soft rope, upon which the loam is put for
making the rough casting-model of the gun, which is turned to a templet; the work is executed over a
long fire, to dry it as it proceeds, and the model is made about one-third longer than the gun itself.
The model, when dried and blackwashed all over, is covered with a shell of loam, not less than three
inches thick, secured by iron bands; the shell is also carefully dried; after this the taper bar is cau-
tiously driven out from its small end, the coil of rope is pulled out, and so likewise is every piece of the
clay model of the gun.
The parts for the cascable and trunnions, which should have been worked separately upon appropri-
ate wooden models, are then attached to the shell. Should the gun have dolphins, or any other orna-
mental figures, they are modelled in wax and fixed on the clay model before the shell is formed, and are
then melted out to make the required space for the metal.
When all is ready and dried, six, eight, or more of these loam cases, or shells, are sunk perpendicu-
larly in a pit at the mouth of the reverberatory furnace, and the earth is carefully rammed around
them; at the same time a vertical runner is made to every mould, to enter either at the bottom or not
higher than the trunnion: the upper ends of the runners terminate in the bottom of a long trough or
gutter, at the far end of which is a square hole, to receive the excess of metal.
In casting brass guns, tapping the furnace is rather a ceremony, and certainly an imposing sight: the
middle and the end of the trough are each stopped by a shovel or gate held across the same; and the
runners are all stopped by long iron rods, held by as many men. When all is pronounced to be ready,
the stopper of the furnace is driven inwards with a long heavy bar swung horizontally by two or three
men, and the metal quickly fills the trough; on the word of command, number one, draw," the metal
flows into the first mould, and fills it quickly but quietly from the bottom; the mould being open at
the top, no air can be accidentally enclosed. Numbers two, three, and four are successively ordered to
draw. The first shovel is then removed from the great channel, and now the guns, five to eight or ten,
as the case may be, are similarly poured and filled to the level of the trough; after which the last
shovel is withdrawn, and the residue of the metal is allowed to run into the square bed or pit prepared
for it. The flow of metal from the furnace is regulated by the tapping-bar, the end of which is taper,
and is thrust more or less into the mouth of the furnace as required; the trough and runners are thus
kept exactly full, which is an important point in most cases of pouring, as it prevents a current of air
being carried down along with the metal.
Large bells are poured much in the same manner, except that the runners are at the top, and the
metal runs from the great channel, through smaller gutters, to every sunk mould, the stoppers for which
are successively drawn. For quantities of brass intermediate between the charge of an ordinary
crucible, and such as require the reverberatory furnace, the large ladles or shanks of the iron-founder are
used; the contents of four or six crucibles being poured into the shank as quickly as possible, and thence
in one stream into the mould.
The author of the article Founding, in the Encyclopedia Metropolitana, minutely describes three ways
of casting large hollow statues, which are briefly as follows:
First; a rough model of the figure is made in clay, but somewhat smaller than its intended size; it is
covered over with wax, which is modelled to the required form, or the wax is worked up in separate
pieces and afterwards attached various rods or cylinders of wax to make the apertures for the runners
and air-holes, are fixed about the figure and led upwards. The whole is now surrounded with a coating
of loam and similar materials, the inner portion of which is ground very fine and laid on with a brush,
like paint; and the outer part is secured with iron bands. When all has been partially dried, a fire is
lighted beneath the grating on which the figure is built, to cause the wax to run out through one or
more apertures at the base, which are afterwards stopped, and all is thoroughly dried and secured in
the pit, after which the charge of the furnace is let into the cavity left by the wax.
Secondly ; the finished figure is modelled in clay, and stuck full of brass pins just flush with its sur-
face, which surface is now scraped away as much as the thickness required in the metal; the reduced
figure is now covered with wax mixed with pitch or rosin, which is worked to the original size with
all the exactness possible. The other stages are the same as in the foregoing; the metal studs or pins
prevent the mould and core from falling together, and they afterwards melt, becoming a part of the
metal constituting the figure.
Thirdly the finished figure is modelled in plaster, and a piece-mould is made around it, the blocks
of which consist internally of a layer of sand and loam, 11 inch thick, and externally of plaster one foot
thick. The mould when completed is taken to pieces, dried, and rebuilt in the casting pit; it is now
poured full of a composition suitable for the core, the mould is again taken to pieces, the core is dried
and scraped to leave room for the metal, and all is then put together for the last time, secured in the
pit, and the statue is cast.
The first plan is the most wasteful of metal; the third, the least so, although it is the most costly
when the time occupied is also taken into account; but it has the advantage of saving the original work
of the artist.
Melting and Pouring Iron.-Iron is usually melted in a blast-furnace, or, as it is more commonly
called, a cupola; although the cupola or dome leading to the chimney, from which it would appear to
have derived its name, is frequently omitted, the two or three furnaces being often built side by side in
the open foundry.
At the basement there is a pedestal of brickwork about 20 to 30 inches high, upon which stands a
cast-iron cylinder from 30 to 40 inches diameter, and 5 to 8 feet high; this is lined with road-drift, which
contracts its internal diameter to 18 or 24 inches. The furnace is open at the top for the escape of the
flame and gases, and for the admission of the charge, consisting of pig-iron, waste or old metal, coke and
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lime, in due proportion. The lime acts as a flux, and much assists the fusion; chalk is considered to
answer the best, but oyster shells are very commonly used where they are abundant.
At the back of the furnace there are three or four holes one above the other for the blast, which is
urged by bellows or by a revolving fan. No crucible is used, and as the fluid metal collects at the
bottom of the furnace, the blast-pipe is successively removed to a higher hole, and the lower blast-hole
is stopped with sand, which partly fuses and secures the blast-hole very effectually.
The front aperture of the furnace through which the metal is allowed to flow into the ladles or
trough, is usually made sufficiently large for the purpose of clearing or raking out rapidly the fuel and
slag, as the process is most laborious, owing to the excessive heat. This aperture is closed by a guard-
plate, fixed on by staples attached to the iron-case of the furnace, in the centre of which plate the
tapping-hole is made: during the time the metal is fusing, the tap-hole is closed by sand well rammed
in, and this if well done is never found to fail.
Many iron furnaces are made octangular, and in separate parts bound together by hoops, 80 that in
the event of the charge becoming accidentally solidified in the cupola, the latter may be taken to
pieces for its removal, and thus avoid the necessity of destroying the furnace. There is frequently a
light framing or grating above the furnace, upon which the small cores are placed that require to be
dried.
In some foundries the cupolas are built just outside the moulding shop, beneath one or more chimneys
or shafts, which carry off the fumes; in such cases the fronts of the furnaces are accessible through an
aperture in the foundry wall, with which they are nearly flush; when the furnaces are lofty there is a
feeding stage at the back, from which the charge is thrown in.
For heavy iron castings, which sometimes amount to thirty tons and upwards in one piece, rever-
beratory or air furnaces are also commonly used; the ordinary charge for these is four to six tons of
iron, and five or six furnaces are commonly built close together, 80 that they may be simultaneously
tapped in the production of such enormous works.*
For melting iron in the small way, good air-furnaces may be used, and also some of the blacklead
furnaces, which are blown with bellows, but this is one of the processes that is not successful upon a
limited scale.
Considerable judgment is required in proportioning the charge for the iron furnace, which always
consists of at least two, and often of half-a-dozen kinds of new pig-iron mixed together, and to which
new iron, a small proportion of old cast-iron is usually added. The kinds and quantities used are
greatly influenced by local and other circumstances, so that nothing can be said beyond a few general
remarks.
When the principal object is to obtain sound castings with a very smooth face, as for ornamental
works not afterwards wrought, the soft kinds of iron containing most carbon, which are most fusible and
flow easily, are principally used. But such metal would neither possess sufficient hardness, durability,
nor strength, for many of the castings employed in the construction of edifices and machinery.
If the cupola contained a little bard pig-iron, but were in great measure filled with old cast-iron,
which had been repeatedly melted, and had become successively harder from the loss of carbon at every
fusion, such castings would be brittle, and sometimes so hard as scarcely to admit of being cut; these
would be equally unfit for the generality of machinery from the opposite causes.
But the same mixture of iron will be found to differ very much according to the size of the objects in
which it is cast; iron, which in a plate one-fourth of an inch thick, may be quite brittle and hard, will
mostly be of good, soft, and useful quality, in a stout bar or plate of two or three inches thick. Thick
castings are necessarily slow in cooling, and are seldom very hard. unless intentionally made SO.
Between the extremes, (say three parts of pig-iron to one of old, or three parts of old iron to one of
pig-iron.) various qualities may be selected; in castings for machinery the general aim is to obtain a
strong, sound, and tough iron; mixtures of this nature which are used for iron ordnance, are called gun-
metal amongst the gun-founders.
The fireman, or the individual having the management of the furnace, therefore always employs the
scales in mingling the different kinds of iron, according to the magnitude and character of the works to
be cast; and until the sorts in use are familiarly known, it is partly a matter of trial, and requires the
same attention as the making of alloys properly so considered.+
A few of the modern cupolas greatly exceed the air-furnaces in effect, as they are calculated to contain upwards of
twelve tons of melted iron. One of these, at the works of Messrs. Nasmyths, near Manchester, is six feet two inches
diameter externally, and lined with Stourbridge bricks. It has three sheet-iron tuyeres, nine inches diameter at the mouth,
the blasts from which enter the furnace at three points of the circle, and they may be slid like telescope-tubes to either of
the four series of holes, as the furnace becomes gradually filled.
There are three other furnaces progressively smaller, arranged beside the first; all of which may be used separately or in
combination, according to circumstances. The blast, which is under corresponding control, is obtained from two revolving
fans, five feet diameter, making above 1000 revolutions per minute.
Messrs. Acramans, of Bristol, have likewise enormous cupola power; they have a series of four cupolas, in which
collectively from forty to forty-five tons of iron may be melted at one time.
In some cupolas the top is contracted by a cone made of iron plate; in Yates's patent, a brick trunk is built upon the
cupola, with narrow arches crussing the trunk at right angles: this economizes the heat by causing the flame and gaseous
matters to be retarded, from pursuing a serpentine course in their escape.
+ When the management of cast-iron was less efficiently understood, it was occasionally alloyed with five or six per cent.
of shreds of copper, thrown into the Indle full of iron to produce a close, sound, strong metal, suitable to three-throw
cranks for pumping machinery. and other purposes. It is said that ten per cent. of copper renders cast-iron malleable,
and that alloyed with copper or tin it is less disposed to rust: all these alloys may be now viewed as matters of
experiment alone.
It is much to be regretted that no protection has yet been found to prevent the conversion of cast-iron into plumbago, or
the carburet of iron, from long immersion in sea-water, or the water of copper-mines, sewers, and other places. This,
which is a most serious inconvenience in dock-works, sea-walls, and mines, arises, says Dr. Faraday, from the circumstance
that the protoxide of iron, formed beneath salt-water, is soluble, and becomes washed away, thus robbing the original
mass of its iron; whereas the peroxide, or ordinary rust formed by exposure to the air, is insoluble, and serves partly as a
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CASTING AND FOUNDING.
When enough iron is melted, (the common charge being two and a half to four cwt., but sometimes
above twelve tons,) the cupola is tapped in front, at a hole close to the bottom, which allows the
whole contents to run out, either into ladles, or, in very large works, into channels leading directly to the
moulds.*
In pouring iron, the means of conveying the melted metal to the flasks, differ with the quantity. One
man will carry from fifty to seventy pounds in a hand-ladle; three to five men will carry from two to
four cwt. in a double hand-ladle, or a shank; larger quantities, amounting sometimes from three to six
tons, are carried in the crane-ladle. These all possess one feature in common, namely, their handles or
pivots are placed but slightly above the centre of gravity of the ladles; they may therefore be tilted
very readily, as their fluid contents, in obeying the law of gravitation, are almost neutral in the operation
of tilting, which they scarcely assist or retard, unless by mismanagement the ladle is over-filled, and
thus rendered top-heavy.
All these ladles are coated with a thin layer of loam, and every time before use, they are brushed
over with blackwash, and carefully dried. The hand-ladle has a handle three or four feet long, with a
crutch or cross-piece at the end, which is mostly held in the left hand frequently the contents of half
a dozen or more hand-ladles are poured simultaneously into the same flask. The shank has a single
handle on the one side, and one made in two branches at the other, and together they measure six to
eight feet in length; the tilting is completely under the command of the one or two men at the double
handle.
The crane-ladle is carried from the furnace to 'the mould by the swinging and traversing motions of
the crane, which is similar to those used at the iron-forges, &c., and in very large foundries, the plan of
the building is divided into imaginary squares with a crane in the centre of every square, 80 that the
ladle is walked from one to the other, even to the far end of the shop, with great facility and expedition.
The bail, or handle of the crane-ladle, is fixed in its perpendicular position by the guard, a simple
bolt which prevents the ladle from being overset by accident until it has reached its destination. Two
long handles, terminating in forked branches, are now fitted by their square sockets upon the swivels or
pivots of the crane-ladle, and secured by transverse keys, after which the guard is withdrawn; and
then two men at the ladle, two others at the crane, and one to skim the dross from the lip of the
ladle, commonly suffice to manage two or three tons and upwards of fluid iron, with great ease and
dexterity.
The observations offered on page 250, respecting the temperature of the metal suitable to different
brass works, might be here in a great measure repeated namely, that the smallest castings require
very hot metal, and a gradually lower temperature is more suitable to works progressively heavier, to
avoid their becoming sand-burned or rough on the face, from the partial destruction of the mould.
When cast-iron is very hot, the metal scintillates most beautifully. far more vividly than a mass of
wrought-iron raised above the welding heat; as the metal cools, the sparks become intermittent, and at
last the metal remains entirely quiet, excepting a multitude of lines vibrating in all directions, as if the
surface were covered with thousands of wire-worms in great activity; this effect lessens until the metal
solidifies. The softest iron shows most of this play of lines, or is said to break the best.
Iron castings are generally much heavier than those of brass, and the melting heat of the metal
being considerably higher, the quantity of gas generated is very much greater; additional care is
consequently required to provide for its escape, or the explosions are much more violent. The sand is
punctured at many places with a fine wire, before the removal of the patterns; sometimes also more
coarsely as soon as the metal has become solidified. The gases issuing from the filled moulds are often
lighted, either by the red-hot skimmer, or by a torch of straw with which the moulds are flogged this
lessens the accumulation of gas and the consequent risk of accident.
The pouring of very large objects in open moulds, such as plates, beams, and girders, is a very beautiful
and grand sight. The metal is led from the furnace, through a gutter lined with sand, into a large
trough or sow, the end of which is closed with a shuttle; when the SOW is full, the shuttle is raised;
this allows the metal to flow very quickly into the mould, but enables it to be kept back should it be
unnecessarily hot; the castings made in open moulds are generally covered up with sand as soon as
the metal is set.
The above, an ' the casting of smaller objects, such as flat plates in open moulds, may appear amongst
the most certain modes of procuring sound castings; but unless the air be well drawn from the lower
surfaces, they will become honey-combed or full of air-bubbles. This defect is avoided by making the
sand-bed sufficiently porous, and pricking it with many holes just below the surface, to serve as
horizontal air-drains.
defence to the metal beneath. When first raised from the sea-water, the plumbago becomes exceedingly hot from the
action of the atmosphere; it may be cut with a knife like an ordinary pencll.-Minutes of Conversation, Inst. Civ. Engineers,
8th Feb. 1842.
. The furnace is not unfrequently tapped whilst the charge of metal is being melted, and in such cases when the
required quantity has been removed into the ladles, the fireman restops the tap-hole by a conical plug of clay on the
ond of a wooden bar; the process is called botting, and requires a dexterous hand, or the whole contents of the furnace
may escape.
t Mr. Nasmyth has added to the pivot of the large crane-handle, a tangent-screw and worm-wheel, by which it may be
gradually tilted by one man standing directly in front at any convenient distance; and another man skims the metal by a
kind of throttle-valve coated with clay, which sweeps into the lip of the ladle, and keeps back the sullage: the axis of the
skimmer is continued as a long rod, at right angles to the first, and also terminating in a cruss. By these arrangements any
precise quantity of metal can be delivered, and the risk of accident scarcely exists.
# In casting lead, tin, &c. on a flat metallic plate, the formation of air-bubbles is lessened by placing a sheet of dry
paper on the plate; it appears to keep down any little bubbles of air or vapor, and to provide a thin channel for their
escape.
But the most perfect example of a porous mould is that invented by Lord Rosse, to avoid the formation of air-
bubbles in those speculums which are cast in open moulds. The plate, or bed of the mould, consists of a great number
of slips of hoop-iron placed edgewise and in contact; they are screwed tight within a frame, and are then turned in a
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A far greater number of works are cast in close moulds, and in the horizontal position; the propor-
tionate quantity of metal is carried to them in ladles: skimmers are held to the lips of the moulds at
the time of pouring, to keep back all the sullage or dross. The number, position, and height of the
runners, are determined by circumstances generally not less than two apertures are provided, the
first for the entry of the metal, the second for the escape of the air, and to allow the metal to flow
through the mould and carry off the sullage.
Sometimes in heavy castings, in addition to the runners, one or more large heads or feeds are made
at the upper part, to supply fluid iron as the metal shrinks in the act of solidifying; and in some such
cases the feed is pumped, by moving an iron rod up and down in the feed to keep the metal in motion,
so that for a time the metal may freely enter and the air escape, to increase the general soundness of
the mass. The pumping should, however, be discontinued the moment the metal begins to stiffen and
clog the iron rod, or in other words to crystallize, otherwise mischief instead of benefit will accrue.
Works which are required to be particularly sound, as some cylinders, pipes, shafts, and plungers,
are cast vertically; the moulds are sunk in the earth, and well rammed to enable them to withstand the
great pressure of the fluid column, without becoming strained or bursting open. Such objects are
moulded and poured with a head, or an additional portion about one-third the length of the finished
casting, as mentioned in respect to brass guns.
In pouring cylinders of tolerably large size, the metal is conducted from the sow through two sunk
passages with side branches, entering the mould in the direction of tangents about one-third from the
bottom; these keep the metal in circulation, and assist the rise of the sullage. Cylinders are also poured
through holes in the loam-cake, other apertures being always provided in it for the escape of the air.
Beneath the iron plate upon which the mould is built, is placed a central mass of haybands, in order
that the air may have free passage to collect, and then to escape upwards to the surface of the earth,
through one, two, three, or more internal or external tubes, as the case may be. The thick cylinders
for hydrostatic presses are closed at one end, and those cast with the mouth downwards require an
air-tube bent at each end, to lead from the core beneath the casting to the surface of the earth; the
gas drives out in a stream, and is immediately ignited like a great torch: others prefer casting them
with the mouth upwards, in order that less risk may exist of locking up air within the casting.
For the very heaviest works, the three or four furnaces are usually tapped at the same moment; the
stream from every one is conducted through a sand-trough, and they all unite in one great trunk leading
to the mould.
In pouring some of the largest cylinders, the trough is led entirely round the top of the loam-mould;
and from the circular channel, sometimes as many as thirty runners, every one of which is stopped by
a shovel held by a man or a boy, descend to the mould, and as many air-holes are made between the
ingates. When the foreman that all the furnaces are in full run, and that the channels are well
supplied, he gives the word, up shovels;" they rise at the instant, and allow the molten stream to
deposite itself in its temporary resting-place.
At the time the cylinder is poured, all the precautions explained in the note, p. 257, are necessary to
give the mould sufficient strength to resist the pressure of the fluid metal; but as soon as it becomes
set, the conditions are altered, and this resistance must be removed from the inner surface, that the
cylinder may shrink, in cooling, without restraint or fracture. Accordingly, after three or four hours'
time, all the diametrical iron stays are knocked away by a vertical weight or monkey, and men descend
by iron ladders into the cylinder, to break down the brick core. The heat is 80 terrific, that they can
only endure it for a minute or 80 at a time, but still the precaution is imperative: and even in com-
paratively small castings of hollow objects, such as cylinders, pans, and boxes, it is desirable to break
down the cores, to prevent the castings from scoring or breaking.
Although some iron castings employed for bridges, girders, and even for machinery, require the
enormous quantities of iron referred to, on the other hand this useful metal is employed for exceedingly
light and beautiful castings, abundant examples of which may be seen in the Berlin ornaments and
chains.* The links of most of the Berlin chains are connected with wrought-iron wire, but Figs. 841,
842, represent a chain made entirely by the process of casting.
lathe to the required curve by this arrangement interstices exist at nearly every point through which the air may escape
downwards.
Speculum metal is perhaps the most untractable of any of the alloys, and it serves to illustrate in a most striking manner
many of the effects that occur in castings generally. Small speculums are cast in sand; as soon as they are set. the sand-
core is pushed out of the aperture, in such as are intended for Gregorian telescopes, to enable them to contract without
fracture, and the red-hot disk is surrounded by ignited wood-ashes or any very bad conductor, to delay the cooling.
These precautions entirely fail with large speculums, as their margins solidify the first, and from the absence of ductility,
the central parts tear away in the act of contraction, and the mass becomes rent or flawed. Lord Rosse considered
this fracture would be avoided by cooling the speculums in uniform layers from below upwards, or as it were in infinitely
thin laminse, and he therefore first employed iron moulds which were cooled by a stream of water projected against their
under surfaces this partially answered with small speculums, but with those of 18 inches diameter it almost always failed,
as the mould cracked before the metal was congealed. A general source of failure was the non-escape of air; this caused
the lower surface to be full of air-bubbles, which it was tedious to grind out.
The plan ultimately adopted was the porous hoop-iron mould, with a marginal ring of sand; the mould was heated to
about 2120 F.; it was filled very quickly, and the moment the metal was solidified, it was drawn into an annealing oven
previously heated to about the same temperature as the casting; so that for small reflectors of nine inches diameter, the
cooling might be extended over about three days, and for large ones of thirty-six inches diameter, over about fourteen days
with these precautions the process was uniformly successful.-See Trans. Royal Soc., 1840, pp. 510, 11. The whole of the
paper On the Reflecting Telescope," pp. 503 to 527, is quite a study for those interested in the construction of telescopes,
and possesses nearly the same interest for the general mechanist.
* We have seen some of these gems of art in the condition in which they left the moulder's hands, and also a portion
of the and employed: notwithstanding the minute size of the castings, some of them are quite hollow, as if stamped
out of thin steel metal.
Professor Ehrenberg says, that the iron employed for them is made from a bog-iron ore, and that the sand is a kind of
tripoli, also containing iron: both are entirely constituted of various kinds of animalcules, several of which are found,
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262
CENTRE OF GRAVITY.
Its length is 4 feet 10 inches, it consists of about 180 links, and weighs 11 OZ. avoirdupois. It was
thus made: the larger links a a were first cast separately; a solid model of the chain about eight inches
long, with core prints, as in Fig. 842, was then moulded; the links a, previously smoked to prevent the
842.
b
b
841.
c
a
c
a
z
adhesion of the metal, were first laid in the mould, and afterwards the sand-cores bb, and a separate
runner was made to every one of the small links c c, 80 as to unite the whole when poured.
CENTRES, main strength of, to find the distance from main centre to centre of cylinder, when length
of beam is given; to find length of beam when distance between main centre and centre of cylinder is
given: how to find centres in erecting Engines. See DIMENSIONS OF ENGINES; and DETAILS OF EN-
GINES; VARIETIES OF PARTS OF STEAM-ENGINES.
CENTRE OF CUTTING. See Locks OF CANALS.
CENTRE OF GRAVITY. The weights of the parts of a heavy body form a system of parallel
forces, whose resultant is the weight of the whole, and whose centre may be determined from the
formulse. This middle point of a body or system of bodies is called the centre of gravity, and
also the centre of the mass of the body or system of bodies. If a body be turned about its centre of
gravity, this point does not cease to be the central point of gravity; for if the three planes, to
which the points of application of the separate weights are referred, revolve at the same time with the
body, the position of the directions of force to these planes alone changes by this revolution; the dis-
tances of the points of application from these planes remain invariable. The centre of gravity is,
therefore, that point of a body in which its weight acts vertically downwards, and which must,
therefore, be supported and fixed, in order that in every position the body may remain at rest.
Every vertical straight line in which this point lies is called the line of gravity; and every plane
passing through the centre of gravity, a plane of gravity. The centre of gravity is determined by the
intersection of two lines of gravity, or that of a line of gravity and a plane of gravity, or by the inter-
section of the planes of gravity.
Since the point of application may be displaced at will in the direction of force, without changing the
action of the force, so a body is in any position in equilibrium
if a point in the vertical line passing through the centre of
80°
gravity is fixed.
843,
If a body M, Fig. 843, be suspended by a thread C A, in
its prolongation A B we have a line of gravity; and if it be
similarly suspended by a second line, we get a second line
A
of gravity DE. The intersection S of both lines is the cen-
tre of gravity of the body. If the body be suspended upon
D
an axis, or be brought upon a sharp edge (knife-edge) into a
state of equilibrium, we shall obtain in the vertical plane
A
passing through the axis, or through the knife-edge, a plane
of gravity, &c. Experimental determinations of the centre
B
M
of gravity, as just pointed out, are rarely applicable; we
have generally to make use of geometrical rules, which will
El
B
presently be given for the determination of this point with
accuracy.
In many bodies-for example, in rings-the centre of gravity falls without the mass of the body. If
such a body is to be fixed in its centre of gravity, it is necessary to connect a second body with the
first, in such a manner that the centres of gravity of both may coincide.
Determination of the Centre of Gravity.-If x₁, x₂, x₈, Y, Y2, Yrs 21, 2₂, 23, &c., be the distances of the
parts of a heavy body from the three planes xz, yx, xy, and the weights of these parts be Pₗ P₂ P₂
&c we then have the distances of the centre of gravity from these three planes,
P,x,+P,x,+ Px,+
x
P₁+P₁+P,+
y
P,+P,+P,+
P,z,+P,z,+P,x,+
z
P₁+P₁+P,+
both in the fossil and recent states, in the neighborhood of Berlin. Vide Paper read by Prof. Ehreuberg, at the Royal
Academy of Sciences, Borlin, July 7, 1836; and also Scientific Memoirs, Vol. 1,, part 3. (Wilkinson's Engines of War,
p. 219.)
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CENTRE OF GRAVITY.
263
If the volumes of these parts be V₁, V2 Vₙ &c., and their densities y₁, y₂ Y₂, &c, we may put, there
fore,
x = V₁γ₁x₁
If the body be homogeneous, i. e. all parts of the same density γ, then:
x =
or since the common factor γ above and below is cancelled:
1. x = V₁ +
2. y V₁
3.
z
=
V1
V2
We may also, instead of the weights, substitute the volumes of the separate parts, and thereby make
the determination of the centre of gravity a problem of pure geometry.
When bodies are a little extended in one or in two dimensions, as thin plates, fine wires, &c., they may
be regarded as surfaces or lines, and their centres of gravity likewise determined with the help of the
three last formula, if for the volumes V1, V₂, the arms or lengths be substituted.
In regular figures the centre of gravity coincides with the centre of figure, as in dice, cubes, spheres,
equilateral triangles, circles, dc. Symmetric figures have their centre of gravity in the plane or axis
of symmetry. The plane of symmetry A BCD, divides a body A DFE,
D
Fig. 844, into two congruent halves; the portions on both sides of this plane
844.
are equal; the moments also on the one side are equal to those on the
other, and, consequently, the centre of gravity falls within this plane. Be-
A
cause the axis of symmetry EF, cuts the plane surface A BCD, Fig. 845,
into two congruent parts, here the portions on the one side are equal to
those on the other; the moments, also, on both sides, are equal, and the
centre of gravity of the whole lies in this line. Lastly, the axis of sym-
metry KL, of a body ABGH, Fig. 846, is its line of gravity, because it
arises from the intersection of two planes of symmetry, A BCD, and E
FGH. For this reason, the centre of gravity of a cylinder, of a cone, and
C
of a surface of revolution, or of a rotating body formed on the potter's
wheel, lies in the axis of these bodies.
E
B
F
846.
D
H
K
847
C
M
845
G
P
D E C
Q
S
R
D
E
A
B
A
L
B
A
F
B
F
X
X
F
N
C
Centre of Gravity of Lines.-The centre of gravity of a straight line lies in its middle.
The centre of gravity of a circular arc A B = b, Fig. 847, lies in the diameter C M, and passes
through the middle M of the arc, for this diameter is the axis of symmetry of this arc. But in order
to find the distance CS=x of the centre of gravity S from the middle point, or centre of the circle,
the arc must be divided into many elementary parts, and statical moments of these, with reference to
an axis XX, passing through the centre C, and parallel to the chord AB=8, be determined.
If be a part of the arc, and PN be its distance from XX, then the statical moment of this
portion of the aru=PQ.PN. If now the radius PC=MC=r be drawn, and QR parallel to AB,
we obtain the two similar 4" PQR and CPN, for which:
PQ:QR=CP:PN,
from which the statical moment of the elementary arc PQ.PN=QR.CP=QR. is determined.
Now, for the statical moments of all the remaining arcs, the radius r is a common factor, and the
sum of all the projections QR of the elementary arcs is equal to the chord corresponding to the pro-
jection of the whole arc; it follows, therefore, that the moment of the whole arc is also = the chord (s)
times the radius r. If this moment be put equal to the arc (b) times the distance x, and therefore
bx we then obtain:
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264
CENTRE OF GRAVITY.
So that the distance of the centre of gravity, from the middle point is to the radius, in the ratio of
the arc to the chord.
If the angle at the centre A BC of the are b be=ß°, the are corresponding to the diameter 1 is ß =
180° ß° W. We have then b=ßr, and s=2 r sin. 2/2 whence it follows, that x = 2 sin. B
For the semicircle ß=- and sin. therefore, = 0.6366 nearly.
To find the centre of gravity of a polygon, or a connection of lines
Y
BCD, Fig. 848, we must seek the distances of the middle points
848.
H, K, M, of the lines = L₁, = La, = LA, &c, from two
D
axes OX and O Y, viz. y1, H, K,
M
M
C
x2, &c.; the distances of the centre of gravity sought from these axes
K
2
K
are then:
B
S
2
S
,
H
8
H
A
0
M1
SIKI
H:
X
For example, the distance of the centre of gravity S of a wire
bent into the form of a A ABC, Fig. 849, from the base is:
NS=x fah+flh a+b 2' h
a+b+c
a+b+c
if the sides opposite to the angles A, B, C be designated by a, b, c, and the height CG by h.
If the middle points H, K, M, of the sides of the triangle
be connected with each other, and in the triangle 80 ob-
848
tained a circle be described, its centre will coincide with the
C
centre of gravity S, for the distance SD from one side
HKis
=DN-SN
K
D
H
ABC
S
= the distances SE and SF from the other sides.
a+b+c
E
F
Centre of Gravity of Plane Figures.-The centre of gravity B
A
MN
G
of a parallelogram A BCD, Fig. 850, lies in the point of in-
tersection of its diagonals, for all strips, such as KL, which are formed by drawing lines parallel to
one of its diagonals BD, are bisected by the other diagonals AC; each
of the diagonals, therefore, is a line of gravity.
C
850.
D
In a plane A A BC, Fig. 851, every line CD from one angle to the
middle D of the opposite side AB, is a line of gravity, for the same
bisects all the elements KL of the A which are given when lines
S
K
M
parallel to A B are drawn. If from a second angle A a second line
of gravity be drawn to the middle E of the opposite side BC, the point
of intersection of the two will give the centre of gravity of the
B
A
L
whole 4.
Because BD=1 BA and = BC, DE is parallel to AC and = 1 A C, and A D ES similar to
the A CAS, and lastly, CS=2SD. If, further, we add SD, it follows that CS+SD, or CD=
3 DS, and, therefore, inversely, DS=} CD. The centre of gravity S lies at 1 of the line CD from
the middle point D of the base, and at ! of the same from the angle C. If CH and SN be drawn
perpendicular to the base, we have also SN=1 CH; the centre of gravity S is at s of the height
from the base of the A.
852.
C
851.
C
S
B
L
K
D
E
M
A
S)
B
A
X
X
DN H
BI
D1 SI Cl
AI
The distance SS₁ of the centre of gravity of a A ABC, Fig. 852, from an axis x X is = DD+1
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CENTRE OF GRAVITY.
265
(CC₁-DD₁), but consequently, =
AA₁+BB₁+CC₁ 3 , i.e., the arithmetical mean of the distances of the three angular points.
Since the distance of the centre of gravity is determined in the same manner by three equal weights
at the angular points of a 4, so the centre of gravity of a plane triangle coincides with the centre of
gravity of these three equal weights.
853.
The determination of the centre of gravity G
C
N
D
S of a trapezium ABCD,Fig. 853, may be
made in the following manner. The straight
line MN, which connects the middle points
St
of the two bases AB and CD with each
other, is a line of gravity of the trapezium;
8
for lines drawn parallel to the bases decom-
pose the trapezium into elementary parts,
whose middle points or centres of gravity lie
B
EMH
F
A
in MN. Now to determine completely the
centre of gravity S, we have only, therefore, to find its distance E H from a base AB.
Let B represent the one, and b the other of the parallel sides AB and CD of the trapezium, h the
height or the normal distance of these sides. Let D E be now drawn parallel to the side BC, we shall
then obtain a parallelogram BCDE of the area bh, and whose centre of gravity is S1, and distance
from AB=4, and a A of the area 2 and centre of gravity S, and whose distance from
AB=Å
The statical moment of the trapezium, about the line AB, is therefore
but the area of the trapezium is = it follows, therefore, that the normal distance of the
centre of gravity S from the base is
854.
D
=
0
3
To find the centre of gravity by construction, let the two bases be prolong-
SI
ed, the prolongations CG made = B and F=b, and the two extreme
E
points obtained, F and G, connected by a straight line: the point of inter-
M
section S with the middle line MN will be the centre of gravity sought;
F
for, from HS= B+26 B+b . h it follows that = B+26 B+6'8 . MN and NS
Ss
2B+_MN____MS__B+26_JB+6_MA+AF__MF
B
A
= B+b 3 ; and NS = 2B+b = B+Lb
which actually arises from the similarity of the triangles MSF and NSG.
To find the centre of gravity of any other four-sided figure ABCD, Fig. 855, we may decompose it by
the diagonal AC into two triangles, and from the foregoing, determine their centres of gravity S, and S,
and thereby a line of gravity S₁S₂ If now the four-sided figures be decomposed into two other tri-
angles by the diagonal BD, and their centres of gravity determined, we obtain another line of gravity,
whose intersection with the first will give the centre of gravity of the whole figure.
We may effect this more simply if we
bisect the diagonal AC in M. apply the
855.
greater part BE of the second diagonal
Y
to the less, 80 that DF=BE, join FM
and divide it into three equal parts; the
B₂
B
centre of gravity lies in the first point S
from M, as may be proved in the follow-
c
C₂
ing manner. MS,=} MD and MS,=
As
A
}MB, consequently S,S, are parallel to
BD, but SS, times A ACD=SS, times
A or DE=SS, BE; there-
Si
fore, SS,: Now, BE
X
X
=DF and DE=BF, consequently SS,
C1
D1
SIBI
Et
A1
0
SS,=DF:BF. The straight line MF
intersects, therefore, the line of gravity
D2
S,S, in the centre of gravity of the figure.
D
Es
If it be required to find the centre of
E
gravity S of a polygon ABCDE, Fig.
855, we must decompose the polygon into
Y
triangles, and determine their statical mo-
ments with reference to two rectangular axes XX and YY.
If the co-ordinates 0B₁=₂, OB₂=y₂ &c., of the extremities are given, the
34
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266
CENTRE OF GRAVITY.
statical moments of the triangles ABO, BCO, COD, &c., may be determined simply in the following
manner. The area of A ABO, from the remark below, = D₁ of the following A
D, yr), &c., the distance of the centre of gravity of A ABO from YY=m=
x₁+x₂+0 3 = 3 from of the centre of gravity of A = us = xg+x, 2 and
&c. If these distances are multiplied by the areas of the triangles, the moments of these
last are obtained; and if the values so obtained are substituted in the formulae:
= D₁+D₁+...
v= D₁+D₁+...
we have the distances и and v of the centre of gravity from the axes YY and XX.
Example.-A pentagon A BCDE, Fig. 855, is given by the following co-ordinates of its extremities
A, B, C, dc.: to find the co-ordinates of its centre of gravity:
Co-ordinates given.
Triple co-ordinates of
Six times the statical
Twice the area
centre of gravity.
moments.
of triangles.
x
y
3 un
3 V"
6D,u"
BD.v.
24
11
24 21 - 11 =
31
32
13237
13664
7
21
7 15 + 21 16 = 441
- 9
36
- 3969
15876
-16
15
16. 9 + 12 15 = 324
-28
6
9072
1944
12
- 9
12 12 + 18 9 = 306
+6
-21
1836
-6426
18
12
18 11 + 24 12 = 486
42
1
20412
- 486
Sum: 1984
22444
24572
The distance of the centre of gravity from the axis YY is:
22444
1984
and from the axis XX:
Remark.-If CA₂=y₁, and
the co-ordinates of the two angles of a tri-
856.
angle BC, Fig. 856, whose third angle C coincides A2
with the point of application of the system of co-ordi- B₂
B
nates, we have the area of the same:
= trapezium B₁ A1 triangle CBB,-tri-
angle CAA=
C
X
B.
A1
The area of this triangle is the difference of two other triangles, CB, A1 and CA, B1, and the one
co-ordinate of a point is the base of the one, and the other co-ordinate the height of the other triangle,
and inversely.
857.
The centre of gravity of the sector of a circle A C B, Fig. 857, coin-
M
cides with that of a circular arc A, B₁ which has the same angle with
the sector, and whose radius C A, is two-thirds of the radius CA of the
M1
sector; for the sector may be divided by an infinity of radii into very
A
B
small triangles, whose centres of gravity are distant two-thirds of the
S
radius from the centre C, and these form by their continuity the arc
A,
B1
A1 M, B₁. The centre of gravity S of the sector lies in the radius CM,
bisecting the surface, and at the distance = chord 2 -CA=
o
arc
3
4 sin. JB
3
ß r; r representing the radius CA of the sector, and ß the arc which measures the angle
at the centre A C B.
For the semicircle ß = R, sin. = sin. 90° = 1, therefore == 0,4244 r, or about 14
For a quadrant x 4 3 Vⱼ R r = 4√₂ 3 r = 0,6002 r, and for a sixth part x = 4 3 r = 0,6366
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CENTRE OF GRAVITY.
267
The centre of gravity of a segment of a circle A B M, Fig. 858, is given, if we put the moment of the
sector CBM equal to the sum of the moments of the segment and the
moment of the triangle A C B. If r be the radius C A, 8 the chord A B,
858.
and A the area of the segment BM, the moment of the sector = the
M
sector X r 2 arc chord arc 2 3 1 r²; further, the moment of the
S
A
S1
B
triangle = triangle X 8 4 3 2 r2 4 = 3 12' 12
S₂
and from this the moment of the segment: A. CS = A x = 3 1
0
consequently the distance sought is 12
For the semicircle s=2 r and hence x = 8 * 4r as found above.
2
In like manner we may find the centre of gravity S of a portion of
850.
a ring ABDE, Fig. 859, which is the difference of two sectors A CB
M
and DCE If the radii be CA=r and CD=n, and the chords
AB=s and DE=8₁, the statical moments of the sectors are:
B
8 8 and 8 therefore the statical moments of the portion of ring =
A
E
8 , or But the area
0
2 (2), provided that ß represents the arc corresponding to the angle at the centre A CB;
the centre of gravity, therefore, of the portion follows from the distance moment area r³—r₁³
Example.-The radii of the surfaces of a dome are: r=5 ft., r₁ = 31 ft., and the angle at the
centre, = 130°, then is the distance of the centre of gravity of these surfaces from their central
point:
4 sin. 65° 5°-3,5" 4.0,9063 125-42,875 3,6252 X 82,125
==
8 are 130° 5'-3,5' 3.2,2689 25-12,25 6,8067 X 12,75
=3,480 feet.
860.
Centre of Gravity of Curved Surfaces.-The centre of gravity of a curved
surface (envelope) of a cylinder ABCD, Fig. 860, lies in the middle S of
C
N
the axis MN of this body, for all the annular elements of the cylindrical en-
D
velope which are obtained by sections drawn through the body parallel to
the base, are equal, and their centres of gravity lie in the axis; these centres
of gravity form a uniform line of gravity. For the same reason, the centre
S
of gravity of the surfaces of a prism lies in the middle point of the straight
lines connecting the centres of gravity of both the bases.
The centre of gravity of the envelope of a right cone A BC, Fig. 861, lies
B
in th. axis of the cone, and is one-third of this line from the base, or two-
M
thirds from the vertex; for this curved surface may be decomposed into an
infinite number of small triangles by straight lines, which are called the
sides of the cone whose centres of gravity form a circle HK, which is distant two-thirds of the axis
from the vertex, and whose centre of gravity or centre S lies in the axis C M.
861
c
862.
H
D
N
E
K
S
H
S
H
G
M
F
A
B
C
0
M
The centre of gravity of a spherical zone A BDE, Fig. 862, and likewise that of a spherical cup,
lies in the centre S of its height MN; for from the rules of geometry, the zone has the same surface as
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268
CENTRE OF GRAVITY.
a cylindrical envelope FGHK, whose height is equal to that of MN, and whose radius is equal to that
of the radius CO of the spherical zone; and this equality also exists in the annular elements, which
are obtained by carrying an infinite number of planes parallel to the circular bases through the same:
according to this, the centre of gravity of the zone coincides with that of the cylindrical envelope.
Remark.-The centre of gravity of the surface of an oblique come or oblique pyramid lies at about
one-third of the height from the base; but not in the straight line passing from the vertex to the centre
of gravity of the base, because slices parallel to the base decompose the surface into rings, which vary
in breadth at different parts of their surface.
Centre of Gravity of Bodies.-The centre of gravity of a prism A K,
Fig. 863, is the centre S of the straight line which connects the centres of
863.
gravity M and N of both bases AD and GK, for the prism may be de-
L
composed by sections parallel to the base into exactly congruent slices,
K
whose centres of gravity lie in MN, and by their superposition make the
N
G
line MN a uniform line of gravity.
For the same reason, the centre of gravity of a cylinder lies in the middle
of its axis.
S
The centre of gravity of a pyramid DF, Fig. 864, lies in the straight
line M F from the vertex F to the centre of gravity M of the base, for all
slices as NOPQR, have from their similarity with the base, their centres
D
A
of gravity in this line.
c
B
If the pyramid be triangular, as ABCD, Fig. 865, each of the four
angular points may be considered as vertices, and the opposite surfaces as bases; the centre of gravity
S is determined by the intersection of two straight lines drawn from D and A to the centres of gravity
M and N of the opposite surfaces A and BCD.
F
D
865.
864.
N
0
D
N
So
S
c
A
C
M
HGM
E
A
B
B
If the straight lines EA and ED be given, we then have EM=}EA and = 1 ED there-
fore M N is paraller to A D and = AD, and the A MNS similar to A DAS. Again, from this similarity
we have MS=1 DS, or DS=3MS, also MD=SD+ MS = 4 and inversely MS=+MD.
Hence the centre of gravity is found to be one-fourth of the line joining the centre of gravity M of the
base with the vertex D.
Further, if the heights DH and SG be given, and HM be drawn, we then obtain the two similar
4° DHM and M, in which from the foregoing SG=1 We may, therefore, say that the dis-
tance of the centre of gravity S of a triangular pyramid from the base is equal to one-fourth, and that
from the vertex three-fourths of the height of the pyramid.
As every pyramid, and also every cone, is made up of
866.
an infinite number of three-sided pyramids of the saine
height, the centre of gravity of every pyramid and cone
is a fourth of the height from the base and three-fourths
from the vertex. We may, therefore, find the centre of
gravity.of a pyramid or cone, if a plane be drawn paral-
lel to the base at a distance one-fourth from the base, and
S
the centre of gravity of the section or its intersection with
DA
the line joining the vertex and the centre of gravity of the
base be determined.
co
If the distances A A1, BB,, of the four angles of a tri-
angular pyramid A BCD. Fig. 866, from a plane HK be
B
A.
known, the distance of the centre of gravity S from this
plane is found from the mean value
M
H
K
4
The distance of the centre of gravity M of the base ABC
B
from this plane is:
8
and that of the pyramid S is:
SS,=MM+(DD,-MM,),
where DD₁ is the distance of the vertex: hence it fullows by combining the two last equations, that:
4
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CENTRE OF GRAVITY.
269
The distance of the centre of gravity of four equal weights
Z
c
applied to the angles of a triangular pyramid, is equivalent
867.
to the arithmetical mean
AA,+BB,+CC,+DD,
A
,
4
B
consequently the centre of gravity of the pyramid corre-
sponds with that of the system of weights.
Remark.-The determination of the volume of a triangu-
lar pyramid, from the co-ordinates of its angles, is simple.
o
If we draw planes XY, XZ, YZ, through the vextex 0 of
C
Y
such a pyramid A BCO, Fig. 867, and represent the dis-
tances of the angles ABC from these planes by 21, 20 23, Yu
yrs Yrs and x₁, In In the volume of the pyramid will be
X
B
A
which will be given, if the pyramid be considered as an aggregate of four oblique prisms.
The distances of the centre of gravity of these pyramids from the three planes are:
= x₁+x,+x, 4 , y₁+y₃+y₂ 4 , and z = 4
Since every polyhedron, as A BCDO, Fig. 868, may be decomposed into triangular pyramids : BCO,
BCDO, we may also find its centre of gravity
Z
A
S if we calculate the volumes, and the statical
moments of the single pyramids.
868.
If the distances of the angles A, B, C, &c.,
from the co-ordinate planes passing through the
common vertex o of all the pyramids, are x₁, x₂,
0
ats, &c., y1, Y2, Yr, &c., 21, 20 Z₂₀ &c., the volumes of
the single pyramids are:
D
0
and the distances of their centres of gravity:
Y
A
26, = 4 4
s
so, ,
4
4
X
D
B'
statz
From these values the distances of the centre of gravity of the whole body may be finally calculated
by the formulæ:
= V₁+V₁+ v = V₁+V₁+ w = V,+V,+.. V,
Example.-A body bounded by six triangles A DO, Fig. 000, is determined by the following values
for the co-ordinates of angles; whence the co-ordinates of its centre of gravity may be found.
Four times
the co-ordi-
Given co-
nates of
Twenty-four times the statical
ordinates.
Six times the area of the triangular
centre of
moments.
pyramids.
gravity.
4 % s
4 w,
S
x
y
z
4v.
24 V.u.
24V.v. vn
24 Va 20n
20
23
41
20.29.28
20.40.30
6 V₁=
41.45.40
45.35.28
12
6 V₂
&BL
23.28.45
31072
77
92
45
29
30
99
2392544
2858624
3076128
23.30.12
41.12.29
45.40.20
40
29.20.12
29.28.38
17204
95
104
78
1634380
1789216
1341912
38
35
20
30.38.40
30.12.35
Sum: 48276
4026924
4647840
4418040
From the results of this calculation, the distances of the centres of gravity from the three planes YZ,
XZ, and XY follow.
1
4026924
1
4647840
1
4418040
=
=
.
= 20,853,
v
=
24,069,
22,879.
4
48276
4
48276
48.76
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270
CENTRE OF. GRAVITY.
The centre of gravity of a truncated pyramid A DQN, Fig. 000, lies in the line MG, which connects
the centres of gravity of the two parallel bases: in order to determine the distance of this point from
one of the bases, we must determine the volumes and moments of the entire pyramid A DF, and the
supplementary pyramid NQF. If the areas of the bases AD and NQ=G and g, and the normal
distance of both = h, the height of the supplementary pyramid will be given from the formulæ:
g = = and x = as also h+ = hVĞ
The moment of the whole pyramid with reference to the base G is now:
8 4 = 12 1 hᵃ that of the supplementary pyramid = (4) =
3 1 VG-VI h'VI' + 12 1 (G-₉) h²g² ; hence it follows that the moment of the truncated pyramid:
Now the solid contents of the truncated pyramid are:
hence it follows, finally, that the distance of its centre of gravity S from the base is
G+2VGg+3g
The radii of the bases of a truncated cone are R and r, and therefore G=, Rª and K rs; we
have then for this
R'+2Rr+8r
867.
R'+Rr+r
D₁
A
Example.-The centre of gravity of a truncated cone of the height =
:N
20 inches, and radius R=12 and r=8 inches, always lies in the line
C
B1
joining the centres of the two circular bases, and is distant from the great-
er by
20 4 2.12.8 + 3.8' 5.528 304 = 2640 8,684 inches.
D
SIG
4
A pontoon is a body enclosed by two dissimilar rectangular bases and
Fx
E
four trapeziums ACC,A,, Fig. 867, and may be decomposed into a paral-
lelopiped AFC₁A₁, two triangular prisms EHC₁B₁, GKC,D₁, and a
B
quadrangular pyramid HKC,; we may, therefore, with the help of these
C
H
constituents, find the centre of gravity of the body.
It is easy to see that the line from the one base to the other is the line of gravity of this body; there
remains only to determine the distance of the centre of gravity from either base. If we represent the
length BC and breadth A B of one base by 1 and b, and that of A1 B₁ and B₁ C₁ of the other base by
1₁ and b₁, and the height of the body by h, then the volume of the parallelopiped = b₁l₁h, and its
moment b₁ l₁ 2 2 1 b₁ 1₁ h²: further, the volumes of the two triangular prisms ([b-b₁] l₁ + [l-l₁]
h 2' and their moment = ([b-b₁] [L-4] lastly, the volume of the pyramid (b-b₁) (1-1)
h 8' and its moment (b-b₁) (l-l₁) h The volume of the whole body is, therefore:
V = (6b₁ 6 (2bl + 2b, 1, bl, + and its
moment Vy = (6b₁ l₁ + + (3b, l₁ + + bl, + b₁
Hence it follows that the distance of the centre of gravity from the base bl is:
2b1+ 2b,4 +b₁ +,l2
Remark.-This formula is also applicable to bodies with elliptical bases. The axes of the one base
are a and b, and of the other a₁ and b₁; the volume of such a body, therefore, is:
V=nh = 24 ab₁ and the distance of the centre of gravity:
ab+3a,b+ab₁+a;b.h
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CENTRE OF GRAVITY.
271
Example.-A dam, A CC₁ A1, Fig. 868, is of the height 20 feet, 250 feet long at the bottom, and 40
feet wide; at the top 400 feet long and 15 wide: to find the distance of its centre of gravity from the
base. Here 40, = b₁ = 15, l₁ = 400, h=20, therefore the vertical distance sought is:
20
M2.40.250 +2.15.400+40.400+15.2502
-
868.
B
N
C
B1,
A1
M
5
D1
If the sector of a circle A CD, Fig. 869, revolves about its radius CD,
there is generated the spherical sector A CB, whose centre of gravity we
869.
wish to determine. We may represent the body as containing infinitely
D
many and infinitely thin pyramids, whose common vertex is the centre C,
B
M
and whose base forms the spherical surface ADB. The centres of gravity
of all these pyramids are at t of the radius of the sphere from the centre
IN
C; they therefore form a second spherical surface A, D₁ B₁ of the radius
B1
A1
CA=CA. But the centre of gravity S of this curved surface is the
centre of gravity of the spherical sectors; because the weights of the ele-
mentary pyramids are uniformly distributed over this surface, and therefore
it is uniformly heavy.
If we now put the radius CA=CD=r and the height DM of the outer
surface = h, we get for the inner CD₁=1 r, and M1 D₁ = consequently
D₁ = M, D₁ = h, and the distance of the centre of gravity of the
C
sector from the centre:
For the semicircle, for example, h=r, therefore the distance of its centre of gravity 6 from the
centre C is :
870.
D
The centre of gravity S of the segment of a sphere ABD,
Fig. 870, is obtained when its moment is put equal to the
difference of the moments of the sector ADBC and that of
the cone A BC. Again, if we put the radius of the cone CD
B
A
BI
M
=, and the height DM=h, the moment of the sector=
= and that of the cone =
F
moment of the segment of the sphere is therefore
C
E1
E
volume of the
segment * (3r-h); hence, the distance in question is:
If, again, we put h=r, the segment becomes a semicircle, and as above, CS=ir.
This formula holds good for the segment of a spheroid A₁ B₁, which is generated by the revolution
of an elliptical arc DA' about its major semi-axis CD=r; for both segments may be divided into
thin alices by planes parallel to the base AB, 80 that the ratio of any two is constant and MA
CE,' 6' CE2 if b represent the semi-axis minor of the ellipse. The volume, as well as the moment of
the segment of the sphere, must be multiplied in order to give the volume and moment of the
segment of the spheroid, and thereby the quotient volume will remain unchanged.
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272
CENTRE OF GRAVITY.
871.
To find the centre of gravity of an irregular body ABCD, Fig. 871,
C
we must decompose it into thin slices, by planes equidistant from each
N F
D
other, determine the solid contents of each slice, their moments with
reference to the first parallel plane A B serving for the base, and finally
F3
connect them together by Thos. Simpson's rule.
The contents of these slices are F₀, F1, F2, F3, F4, and the whole
F'
height or distance of the outermost parallel plane is=h; the volume
S
of the body, therefore, according to Simpson's rule, (approximately,) is:
E'
B
M
If we multiply in this formula each of these volumes by their distance, we obtain the moment:
lastly, by dividing one expression by the
other, we get the distance required:
F+4,+2,+,+
4
If the number of elementary slices = 6, we have:
6
It is easy to understand how this formula may be altered when the number of slices is different
from the above. This rule requires only that the number of the slices should be even, and, therefore,
that of the surfaces uneven.
In most cases of application, the determination of one distance is enough, because, besides this, a
line of gravity is known. The bodies commonly met with in practice are solids of rotation, generated
in a lathe whose axis of rotation is the line of gravity.
This formula, lastly, is applicable to the determination of the centre of gravity of a surface, in which
case the sections F°, F1, F2, become lines.
Example.-1. For the parabolic conoid A BC, Fig. 872, which is generated by the revolution of a
parabola ABM about its axis A M, we obtain by making the section DNE, the following:
The height AM=h, the radius BM=r, AN=NM=₄, and hence the radius DN=,
1/2
The area of the section through A is F₀=0, of that through = F1 = W
2
and of that through M=F,=.r. Hence the volume of this body is:
v=+++= 5)
on the other hand, the moment is r2 r²) = = 23 = lastly, the distance of
the centre of gravity S from the vertex, is
872.
873.
R
B
M
ro
A
A
"1
M
SN
S
A
T2
rg
E
N
T4
c
D
C
Example 2.-A vessel ABCD, Fig. 873, has its mean half breadths, r₀=1 inch, r₁=1,1 inch,
r₂ = 0,9 inch, r₃=0.7 inch. r₄=0,4 inch, with a height M N = 2,5 inch. The sections are F₀=1.π,
F₁=1,21.π. F₂=0,81.π, F₁=0,49.π, F4=0,16.x; hence, the distance of the centre of gravity from
the horizontal plane A B, is:
1 +4.1,21 x+2.0,81 x +4.0,49 * +0,16*
4
14,60 9,58 2,5 36,50 0,9502 inches.
The capacity, therefore, cubic inches.
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CENTRE OF GRAVITY.
273
An interesting and sometimes very useful application of the laws of the centre of gravity is the
properties of Guldinus, or the barocentric method. According to these, the volume of a body of revo-
lution (or of a surface of revolution) is equal to the product of the generating surface, (or generating
line,) and the space described by its centre of gravity during the generation of the body or surface of
revolution. The correctness of this proposition may be made evident in the following manner.
Guldinus' Properties.-If the plane area ABC, Fig. 874, revolve about an axis XX, each element
F, F1, &c, of the same will describe an annulus; if the distances F₁ G,, F, G, &c., of these elements from the
axis of revolution XX, be rg, &c., and the angle of revolution therefore the are
corresponding to the radius 1=a, the circular paths of the ele-
ments will be r₂ &c. The spaces described by the ele-
874.
ments F1, F₂ &c., may be considered as curved prisms having the
XI
bases F1, F₂ &c., and the heights &c., and the volumes
F1 a, F, &c., and therefore the volume of the whole body
If MS = x be the distance of the centre of gravity S of the genera-
"
M.O
ting surface from the axis of revolution, we have also (F₁+F₁+...)
8,
consequently the volume of the whole
body V =(F,+ F,+...) x But F,+F,+. are the contents
M
-
of the whole surface F, and x a the circular arc 10 S,, described by
875.
the centre of gravity S; consequently, V = Fw, as above enunci-
X
ated. This formula holds good also for the revolution of a line,
because it may be considered as a surface made up of infinitely
small breadths; F is namely =Lw: i. e. the surface of revolution
,A
A
is a product of the generating line (L) and the path (w) of its centre
of gravity.
Example.-1. In a half ring of an elliptical section ABED, Fig.
B
P
-)
10
B
875, let the semi-axis of the section be CA=a and CB=b, and
let the distance CM of the centre C from the axis X =r ; then
x
the elliptical generating surface F = π ab, and the path of the
centre of gravity (C) hence the volume of this half ring V = x2 and that of the whole
ring = If the dimensions be, a=5 inches, b=3 inches, r=6 inches, the volume of one-
fourth of the ring = = = 444,132 cubic inches.
Example.-2. For a ring with a semicircular section A BD, Fig. 876, if CA=CB=q represent
the radius of this section, and MC=r that of the hollow space or neck, the volume is
V (+)
877.
876.
D
X
A'
1B
C
M
S
JD
X
IN
Example.-3. To find the surface and volume of a cupola ADB of a dome, Fig. 877, half
the width MA=MB=a, and the height MD=h, are given. From both dimensions it follows
that the radius CA=CD of the generating circle =r= 2a + and the angle ACD subtended at
the centre by AD=a, if we put the sin. a=, a The centre of gravity S of an arc DAD,=2AD =
is determined by the distance CS=r chord arc A D MD sin. ; further, CM=r cos.a, consequently
a
the distance MS of the centre of gravity S from the axis MD
and the path described by the centre of gravity in the generation of the surface ADB=2xr.
sin.
The generating line DAD₁= 2 r e, and since it only is required to determine
the half ADB, this line = a, and consequently we must put the whole surface 0=ra.2xr
35
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274
CIDER-MILL AND PRESS.
Very commonly a°=60°; therefore, sin. a = JV3, and the cosa=}; hence it follows
that mo= =
For the segment DAD₁ = A = sin. 2 a) the distance of the centre of gravity from the
centre is = sin. hence the distance from the axis MS = CS - CM =
finally, the path of this centre of gravity described in one revolution is:
The volume of the whole body generated by the segment D A D₁, is given if this path be multiplied by
A. and the volume of the dome found by taking the half of this: therefore, V = * sin.
sin. COS. a). For example, and COS. a = hence:
Remark.-Guldinus' properties find their application in those bodies which arise when the generating
surface 80 moves that in every position it remains perpendicular to the path of its centre of gravity,
because we may assume every small part of a curvilinear motion to be circular. From this we may
find the solid contents of the threads of screws, and sometimes also calculate the masses of earth,
heaped up or removed, as in the case of canals, roads, railroads, dc.
CHALK See RAILWAY ENGINEER-
ING.
CHAMBERS OF LOCKS, form to be
given to. See LOCKS OF CANALS.
CHEESE-PRESS. Dick's Anti-
878.
Friction Cheese-Press.-In the annexed
cut is represented the method of apply-
ing Dick's anti-friction power to the
pressing of cheese. By the use of this
press the whey is entirely removed, and
half the labor usually required in the
manufacture of cheese is saved, it being
ready for market or transportation as
it comes from the press, without risk or
loss to the purchaser, and the consequent
vexation 80 frequent in the case of the
method originally pursued. The press-
ing may be carried to any extent deemed
requisite, without danger to the press,
the working portions of the press being
made of iron, and capable of sustaining
the force that may be applied. Attached
to this press is the platform scale; so
that the cheese can be accurately
weighed before it is removed from the
press-a matter of great convenience
and importance to the manufacturer
and vender of these articles, as well as
to the purchaser, who can depend upon
the weight marked upon it as strictly
accurate. In fact, the advantages of
this press, above others, must be at first
view apparent, and the power such that
it will come into general use.
CHIMNEYS, OF LOCOMOTIVES.
See DETAILS OF ENGINES: what to do if
carried away. See MANAGEMENT OF EN-
GINES.
CHISELS. See PLANES AND CHIS-
ELS.
CIDER-MILL AND PRESS. Chapin's Portable Cider-mill and Press-This machine is arranged
in one compact body, upon a set of heavy wagon-wheels; and including these, the whole weighs but
about 2,700 lbs. It may be drawn from one orchard to another by a single pair of horses, and is put
in operation while standing on the wheels. With the power of one horse and the labor of two men
and a boy, it is capable of expressing from twelve to twenty barrels of cider per day. The apples are
ground by four fluted cylinders or nuts, which mesh into each other, and are within the mill, as at E;
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CIRCULAR SAW.
275
these are driven by a horse attached to the sweep C. Below the cylinders is the press crib, made of
perforated plank and grates, and when the falling poinace has formed a sufficient cheese in this, the
follower-planks and block F are introduced upon the upper surface; the sweep C is transferred to the
heads of the screws; and the pressing is performed either by hand or horse power. A channel on the
margin of the platform 0, conducts the cider which issues through the sides of the crib, into the tubs.
When the pressing is finished, the platform is lowered to the ground, the tubs and rear grate B are
removed. and the cheese is drawn out in a mass upon a separate side platform, by a horse, to any con-
venient distance from the mill. The sweep is then placed upon the shaft H of one of the cylinders,
and the grinding is again commenced. A band of iron on each side, shown at D, confines the press-
beam to the platform during the pressure of the screws.
They are manufactured by Nathan Chapin, Syracuse, N. Y.
879.
E
CIRCULAR SAWS. See SAWS.
CIRCULAR SAW for Cutting Veneers. The object of this machine is to cut up logs of fine wood
into slices or leaves for purposes of veneering. From ten to sixteen of these slices may be cut from
an inch of wood; and considering that the logs are from 9 to 36 inches broad, some idea may be formed
of the nicety of the operation, and of the steadiness and rigidity of parts required in the machine for
the efficient discharge of its functions.
The principal feature of the machine is a circular saw, marked bb in the cuts, which is built in seg-
ments upon a strong, rigid, cast-iron frame A, which, it will be observed from the sections and the plan,
consists of a series of arms radiating from a central eye, dished in form, like an ordinary carriage-
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276
CIRCULAR SAW.
wheel, and flanged on the hollow side, to secure rigidity; these arms terminate in a broad, flat ring,
upon which the segments of the saw are fastened by means of short countersunk screws, as exhibited
in Fig. 882. The saw-frame, as it may be termed, is hung upon a strong shaft P, which runs in bear-
ings located on wall-plates, secured to a foundation by holding-down bolts. Upon the same shaft are
hung the driving-pulleys BB, whence the motion of the machine is derived.
While the axis of the saw-frame remains stationary during the operation of the machine. the log of
wood C. which is being cut up, is urged forward against the saw by a gradual progressive motion,
being fixed for the purpose on a sliding carriage D E G, moved by a self-acting apparatus.
First of all, the carriage runs upon two parallel rails T R, bedded on two longitudinal square tim-
880.
c
R
E
B
B
0
M
v
P
K
N
bers, and firmly bolted down to them. The lower part of the carriage G, slides on these rails at three
surfaces of contact on each rail, as may be seen in Fig. 882. The upper part of the carriage E is held
down to the part G by means of dovetail bevel surfaces, where a broad piece of metal is introduced
between the snug cast on the end of the piece G and the bevel edge of the piece E. and bolted down
to G, thereby holding down the piece E to G-admitting also of a transverse sliding motion of the
piece E; (see Fig. 882.) From the piece E, three flanged arms are erected, to which is bolted the
timber frame D, on which is immediately sustained the log C. The frame D consists of two longitudinal
square timbers, the lower one of which, as shown in Fig. 880, rests upon short flanges projecting from
the faces of the arms of the piece E, and is thus prevented from sliding down; these timbers are
connected by a series of spars, checked at both ends into the timbers. The spars are finished flush
on their exterior surface, on which they receive the log C, which adheres to them by means of a film
of glue interposed. The spars are set at an inclination backwards, as they are thus more directly in
the line in which the strain comes upon them.
The self-acting motion for moving the sliding carriage, and thereby feeding the saw, is driven from
the main shaft. A rack H fixed on the under side of the carriage, is driven by a pinion on the end of
the horizontal shaft T, Fig. 880, upon which the triple-grooved pulleys M 0 run loose, ready to be
catched alternately by the sliding-clutch V. The pulleys M are driven by the pulleys K on the end
of the main shaft, the motion being reduced by means of the intermediate pulleys L The pulleys 0
are driven directly by the pulleys N on the main shaft. The pulleys K L M are those which feed the
saw, the band K L crossing itself, and LM being an open band. The pulleys N 0 reverse the motion
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by
Google
circular SAW.
277
of the log-frame, and carry back the log to prepare it for a succeeding cut. Three different speeds are
provided in these pulleys.
The motion for feeding the saw transversely-that is, for shifting the log in the direction of its
breadth, in setting it for another cut-is effected by the screws SS, the bearings of which are fixed
on the sole G, and their screwed parts working in nuts fixed on the piece E. On these screws, worm-
wheels are fixed, driven by worms on a horizontal shaft, which again is driven by hand, by means of a
pair of small meter wheels-all which is represented in the plan, Fig. 881. The lateral motion of the
piece E is directed by the bevel surfaces between which it is confined.
881.
@
00
0
00
M
L
H
0
C
D
E
B
B
C
H
A
@
6
Action of the Machine-The log being fixed to the frame DE, and the end of it adjusted in contact
with the edge of the saw, by means of the longitudinal and transverse sliding-surfaces already described,
the clutch V is geered with the pulleys M, the driving-bands being shifted to the proper speeds. The
driving-belt is then shifted to the driving-pulley B, and the saw is caused to revolve at a high speed,
the self-acting motion at the same time urging forward the log. The veneer, as it separates, glides off
the back of the saw-frame, as shown at F in Fig. 881, and, when cut off, is carried away. The clutch
v is then reversed into geer with the pulleys O: thus the motion of the sliding-carriage is reversed,
and the log is returned to its first position in front of the saw. The clutch is then entirely disengaged,
and the transverse motion is applied to the frame DE, by which the log is shifted in front of the saw,
in readiness for the next cut. The clutch V is now engaged with the pulleys M, and the process is re-
peated as already described.
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278
CIRCULAR SAW.
The speed at which the saw is driven is about 180 revolutions per minute, which with a diameter of
twelve feet, gives a velocity of 6784 feet in that unit of time. The feed-motion for that velocity is
about t inch for every revolution of the saw, making 111 feet per minute of veneer cut. The feed-
motion is, however, modified according to the quality of the log under operation: often it does not
exceed a half of that stated; and in some mills the velocity of the saw is also less.
5
as
H
a
Y
A
X
A
Transverse Section.
X
G
Plan of the Lower Carriage.
A
H
E1
M
M
R
Literal References.-A. the saw-frame, with the saw bb attached to it.
BB, the fast and loose pulleys on the saw-frame shaft.
C, the log which is to be cut into veneers.
D, the timber-frame to which the log is attached.
E, the cast-iron frame to which D is bolted. which slides laterally under dovetail surfaces.
F, the veneer as it comes from the saw, gliding off the saw-frame.
G, the lower part of the sliding-carriage, which slides longitudinally on rails laid on tim
bers.
H, the rack attached to the sliding-carriage, and driven by a pinion on the shaft of the feeding
apparatus.
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CLOTH-SHEARING MACHINE.
279
K, grooved pulleys on the end of the main shaft,
for driving the feed-motion.
a
L, intermediate pulleys, driven by the pulleys
K.
M, pulleys loose on the pinion shaft, driven by
the pulleys L
N, pulleys on the main shaft, for reversing the
motion of the log.
0, pulleys loose on the pinion shaft, driven by
the pulleys N.
P, the saw-frame shaft.
RT, longitudinal slides on which the sliding-
frame is moved.
-
S, screw and wheel motion for shifting the log-
frame laterally.
V, the clutch carried round with the shaft on
which it slides, so that it may be put in geer
S
with the loose pulleys MO, alternately.
A
Saw-mill Rollers for Planks.-Fig. 883 repre-
A
sents an arrangement for steadying the planks
or logs as they are moved forward in saw-mills.
G
R
H
A A, are adjusting-screws, working in nuts
fixed on the frame of the machine, for setting the
roller-frame against the logs.
B B, are adjusting-screws for setting the plank-
frame HS.
C C, pinching-screws, acting by the intervention
of levers upon the rollers.
S
DD, levers jointed to the roller-frame, trans-
883.
mitting the pressure of the screws CC to the
rollers.
E E, spring-levers intermediate between the
S
screws C and the levers D.
F G, F G, the soles of the roller-frames, guided
in their traverse motion by dovetail surfaces upon
R
HH.
H H, the plank-frames, into the ends of which
a
H
are inserted the screws B B.
II, clutch-frames, through which the journals
A
of the rollers pass; they transmit the pressure of
the levers D D to the rollers.
R R, the rollers which press the planks against
the uprights SS, and steady their motion; the
ends of their journals move in grooves in the
framing F G, FG.
SS, uprights rising from the plank-frames
H H, against which the planks are held by the
rollers.
CLOTHING BOILERS AND CYLINDERS,
saving fuel from. See MANAGEMENT OF ENGINES.
CLOTH-SHEARING MACHINE Invented
by Milton D. Whipple, of Lowell, Mass., for
shearing cotton cloth, or preparing it for being
printed.
Fig. 884 denotes a top view of the machine;
B
Fig. 885 is an elevation of one side of it; Fig.
886 is an elevation of the other side of it; Fig. 887 is a central vertical and longitudinal section of it;
Fig. 888 is an elevation of the front end; and Fig. 889 is an elevation of the rear end.
The machine to be described is calculated to remove from the surface of calico or cotton cloth the
furze, nap, knots, or other matters which are usually taken off by the process of picking by hand, and
singeing by hot rolls or plates, or the flame of gas.
Mr. Whipple does not confine his invention to the shearing of cotton cloth alone, as it may often be
used to good advantage on many other thin cloths, such as mouslin de laine, for instance.
In the drawing, A denotes the frame-work of the machine constructed of iron, wood, or any other
suitable material; B is the driving-shaft extending across the frame, and made to run in proper boxes
C is a fast pulley, and D a loose pulley arranged on the shaft, motion being given to said shaft by the
belt, from the driving power being made to operate on the fast pulley EF G H are four series of
revolving helical shearing-cutters applied to, or arranged respectively on horizontal shafts IKLM,
whose journals are supported in boxes N N N, &c. Beneath each of these series of cutters is one of a
series of blades or horizontal knives 000, &c, which is attached to a head-piece or holder P. The ends
of the said head-piece have adjusting-screws Q R, Q R, applied to them in such manner as to admit of
the correct adjustment of the holder P, and blade O, with respect to the rotating helical cutters over and
in advance of them. At some distance in front of each of the blades 00, is a rule or ledge S, whose
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CLOTH-SHEARING MACHINE.
upper edge is placed somewhat above the under surface of the knife or blade 0; the position of said
rule S, and the top of it with respect to the cutters and blades, being as seen in the drawings. Each of
the series of revolving cutters has a pulley T fixed on it. There is a driving-pulley V on the driving-
shaft. A belt V passes arounl the said pulley V, and the two middle pulleys TT, as seen in Fig. 885.
It is by means of the said pulleys and belts, that the several series of helical cutters are put in
revolution.
A cylindrical brush X is placed in advance of the first rule S, and so as to bear against the cloth Y,
884.
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NO
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60
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as it passes from the under surface of a friction-roll on cylinder Z to the top of the first rule S; the said
brush is revolved by a belt, which passes around two pulleys bc, the former of which is fixed on the
driving-shaft, and the latter on the shaft of the brush x. In the rear of each blade O, and between it
and the rule or ledge S, directly in rear of it, is a long transverse horizontal brush z, which rests on the
cloth, and removes any superfluous lint, and lays the nap of the cloth as it passes underneath in the
proper direction to be acted upon by the cutters in rear of it; e and f are a pair of drawing-rollers
arranged at the rear end of the machine, as seen in Fig. 887. The lower one has its journals sustained
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CLOTH-SHEARING MACHINE.
281
in boxes, applied to the ends of two weighted levers g, H, by the action of which it is pressed against
or towards the upper roller.
The upper roller has a geer-wheel i fixed on its shaft; the said geer-wheel is made to engage with a
toothed pmion K fixed on a shaft i; on said shaft i is a pulley m, around which a band n passes to
a pulley 0 fixed on the driving-shaft. By means of the pulley, belt, and geers, the upper drawing-
roller receives the motion.
A stretching-bar P is arranged at the front end of the machine, and directly over the roller z. The
upper edge or surface of the bar has grooves or flutes made diagonally across it, those on the side of the
centre of the bar being caused to run in a direction opposite to those on the other, as seen in the figures,
the object of this bar being to stretch the cloth in lateral directions.
When the cloth first enters the machine, it passes over a cylindrical rocking-bar q, (see Fig. 888,)
which is supported so as to rock or vibrate laterally on a post r, made to rise upwards from a trans-
verse bar S. From the centre part of each end of the bar, one of two rods or journals i u projects, as
seen in Fig. 890, which denotes a vertical and longitudinal section of the bar, and parts connected with
it. On each of the journals one of two pulleys v w is placed, and revolves; each of said pulleys being of
a diameter corresponding to that of the cylindric bar q. The external curved surfaces of the pulleys
are made rough by having sand-paper, or sand or emery glued to them, and each of said pulleys has a
neck or hollow shaft x extending from it, and through a vertical groove y, made in one of two plates or
standards 2 a. A small geer-wheel b is fixed on each hollow shaft x; the said geer-wheel being made
to engage with a vertical toothed rack c, affixed to the standard, as seen in Figs. 885 and 886. The pecu-
liar object of the said rocking-bar and mechanism applied to it, is to cause the cloth, as it rises up from
the pile on the floor, to be delivered centrally upon the front series of helical cutters; or in other words,
80 that one of its selvages shall be at the saine distance from the adjacent end of the series of cutters
as the opposite selvage is from the end thereof adjacent to it.
The length of the rocking-bar is made equal to, or somewhat greater than the width of the piece of
cloth: when the piece is drawn through the machine by the action of the drawing-rollers, it is made to
pass over the rocking-bar. If either selvage or edge of the piece, while 80 in motion, should happen to
project at any time beyond the contiguous end of the rocking-bar, and upon the surface of the adja-
cent pulley v or to, it will cause said pulley to turn on its journal; the consequence of which will be,
that the toothed pinion b will be made to revolve by it; which motion of the pinion will cause it, by its
connection with the rack into which it goes, to rise upwards and tilt the rocking-bar into an inclination
to the horizon, thereby inducing the cloth to move laterally on the rocking-bar, or towards the pulley
at its opposite end. Should it by chance run over the last pulley, a contrary action will occur, and
the rocking-bar will be tilted in an opposite direction, and so as to induce the cloth to slide or move
towards the other pulley. The apparatus is thus self-acting, and operates with all the desired regu-
larity and precision to introduce the cloth centrally into the machine.
Directly over each of the series EFGH of revolving helical cutters is an oiling apparatus, which
consists of a strip of cloth d, affixed to a long bar e, whose ends have journals which are supported
and move in the tops of posts or standards f G. One of the journals of each of the bars e' c¹, &c., has
an arm h extending downwards from it, and passing through one of a series of staples i, &c., driven
into a long slide-bar K.
This slide-bar is sustained by bearings l m, fastened to the side of the frame A, and its rear end rests
against a cam n, fixed on the shaft of the upper driving-roller. The said cam during part of its rota-
tion forces the slide-bar forward, and longitudinally, in such manner as to move all the arms h h simul-
taneously, and thereby cause all the strips of cloth to rise above their respective series of cutters. The
retraction of the bar may be effected by a spring properly applied to it, the said retraction causing all
the stripe of cloth to descend upon the cutters. Each strip being saturated with oil, will, when it
is carried in contact with the knives or cutters, lubricate their edges.
The next portion of the machine to be described is that by which the lint and extraneous matter,
removed from the surface of the cloth by the helical cutters, are taken from the machine. For this
purpose is placed above the frame A, a large pipe or hollow cylinder or vessel n, one end of which
should be stopped up while the other should connect with an air-exhausting apparatus of some proper
kind.
From this pipe others, 0 0, &c., extend downwards, and open respectively in vertical, triangular, or
other proper-shaped vessels PP, each of which is placed respectively just in rear of the cutters
and rotary brush, an! is open at bottom, and shaped and made as seen in the drawings.
Each of the bars to which the blades 00, &c., are attached is curved upwards, as seen at q, 80 as to
direct the lint and the conductors PP. Now when air is drawn out of the pipe 72 by the exhausting
apparatus, an atmospheric current will rush up each of the vessels and pipes extending downwards from
it. In the passages of said currents into the adjutages of the conductors PP, and through the same,
and pipe O, they will carry with them the lint and extraneous matters removed by the cutters and
rotary brush.
In order that the cutters may perform their operation on the cloth in a proper manner, a reciprocating
lateral movement as well as a rotary movement may be given to them: this is effected in the following
manner.
On each cutter-shaft is a grooved pulley r1, into the groove of which the upper end of one of four
vertical plates SS, dc., is inserted, the said plates being secured to a horizontal slide-bar t, which is
arranged and operated by a cam, and a retracting spring, in substantially the same manner as is the
slide-bar K, hereinbefore described. The upper end of each of the plates S is bent out of parallelism
with the side of the frame A, as seen in Fig. 884. Now when a reciprocating rectilinear movement in
a longitudinal direction is imparted to the slide-bar v, and plates SS, the pressure of the plates on the
slides of the grooves of the pulleys rr, &c., will cause the various series of cutters during their revolu-
tions to move back and forward laterally.
36
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887.
886.
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CLOTH-SHEARING MACHINE.
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888.
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890.
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CONDENSING ENGINE.
Two straight bars d' er are arranged at the front end of, and transversely across the machine, and
parallel to one another; one of them, viz. d³, being fixed firmly in position while the other is made
adjustable, or has adjusting-screws or other proper contrivances applied to it for the purpose of regula-
ting its distance from the other bar.
The cloth is passed and moves between these bars, they being adjusted at such a small distance
asunder, as will be just sufficient to allow the cloth to pass between them, while no knot or picker-wires
or other extraneous substances which would be likely to injure the cutters, present themselves in the cloth.
When such matters exist on the cloth, and are carried in contact with the bars, they will either be
removed by the draft on the cloth, or they will stop the motion of the cloth until they can be removed
by an attendant.
The next and last portion of the machine to be described is the folding apparatus, which consists of a
platform V, supported on two rails X X, by four or any other suitable number of wheels W W. The
said platform or carriage should have a reciprocating rectilinear motion imparted to it in a longitudinal
direction by suitable mechanism. That employed is as follows:
The carriage has a long plate of metal W secured transversely to its under side; through the plate
a long slot X is cut, into which one end of a crank J is inserted, the crank being made to project
from the top of a vertical shaft 2. which turns in proper bearings of a post or standard a³, supported on
the floor on which the machine rests. On the shaft is a bevelled geer a³, which engages with a bevelled
pinion b⁸, which is fixed on a horizontal shaft c3, which has a pulley d' secured to its outer end around
this pulley, and a pulley e2 fixed on the shaft of the upper draw.roller to the carriage V, by said pulleys
e², d², belt f2, shaft c², geers b², a3, and crank y and slot x acting together. The constant fore and
back movements of the carriage causes the cloth, as it passes from between the draw-rollers, to be laid
on it in regular folds. The manner in which the cloth is passed through the mechanism is seen in b 3
at Fig. 887.
It has been found from experience that the cloth is much better sheared when subject to the action
of several series of rotating helical cutters, arranged and operating together as above, than it is when
successively subjected to the action of one revolving series of such cutters.
The process of shearing, besides being performed much quicker by two or more series of rotary
cutters and their adjuncts, as above specified, is more easily performed, and with less liability of injury
to the texture or thread of the cloth.
By reference to the drawing, it will be seen that the position of the top edge of each of the ledges S,
with regard to the bottom of the cutters or cutting-blade O, is such that the cloth, after passing over
the top of said ledge, is by the ledge borne up against the under side or edge of the blade O, and so
that the fur or nap which is to be removed is carried against the edge of the plate, and is cut off by
the action of the revolving cutters. Consequently, should there be any knots, motes, or foreign
substances projecting from the upper surface of the cloth, they will be removed by the upper surface
and blade, and without injury to the cloth.
If the cloth passed directly over a ledge or rest placed under the cutters, as in machines for shearing
broadcloths, cassimeres, &c., or thick and long-napped cloths of like character, it would be constantly
liable to be cut into strips or otherwise injured.
By doing away with the rest, the cloth has the opportunity of falling, moving, or springing away from
the blade when any very large knot or extraneous substance is presented to it and the cutters. The
manner in which the cloth is borne against the under surface of each of the blades O, viz. by means of
a ledge or rule S. or any equivalent in rear of each blade, we may dispense with the swing-bar which
is used in the machine of Courlier to bring the cloth up to the blade, it being subject to the same
objections as in the rest.
The machine of Courlier is described at page 8 of Traité Théorique et Pratique de l'impression des
Tissus, par J. Persoz, tome deuxieme, Paris, 1846.
Mr. Whipple claims for his invention the manner of supporting the cloth during the performance of the
cutting operation, viz. by the under side of the blade o of each of the series of cutters in combination
with two ledges SS, or other mechanical equivalents whose upper edges shall be arranged in a plane
with or a little above the said blade; the same enabling him not only to dispense with a rest such as in
common shearing machines, but with the swing-bar used in the machine of Courlier.
He also claims the combination of two or more series of helical cutters E F G H, blades 0, dc
guide-rules SS, &c., and drawing-rollers as arranged, and operating together substantially as above
specified.
Mr. Whipple also claims the apparatus by which the cloth is received at the front end of the
machine, and caused to pass centrally into it or towards the cutters. Said apparatus being a combi-
nation of a rocking-bar, two pulleys, and two great pinions and racks or any mechanical substitute, the
whole being arranged and made to operate together substantially as described.
Mr. Whipple further claims in the machine's combinations with the shearing machinery, the apparatus
arranged over it for the purpose of removing the lint by upward currents of air as described; and the
reciprocating carriage or moving platform for folding the cloth. in combination with the shearing
machinery, the same being arranged and made to operate substantially as above explained; and the set
of parallel bars dᵃ, e$, as combined with and applied to the shearing mechanism in manner and for the
purpose before described.
COCKS, proportions of. See DETAILS OF ENGINES.
CONDENSING ENGINE of thirty-horse power, by Neilson and Mitchell, Glasgow. This form of
beam-engine, in which the frame is composed of six fluted columns, supporting an entablature for
carrying the main centre pedestals, has a very light and handsome appearance, and besides possesses
the maximum capability of resisting severe working strains. It belongs, indeed, to the most economical
class of engines, as respects durability and expense of maintenance for repair.
Fig. 891 is a side elevation of the engine, with a portion of one of the columns at the steam-cylinder
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CONDENSING ENGINE.
285
ERIE
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COINING MACHINE.
end removed to allow the internal arrangements of the cylinder and nozzles to be shown in section.
The section is taken in the plane of the axis of the cylinder, and is continued through the air-pump,
condenser, and hot-water pump.
Fig. 892 is an end elevation taken upon the cylinder end of the engine.
General Description.-The sole-plate A consists of a single casting, with three shoes in each of the
side-pieces, which are bored to receive the turned feet of the columns. The entablature C consists
likewise of a single casting, with corresponding recesses bored to the diameter of the projecting ends of
the columns, which are firmly secured at top and bottom by strong cotters. The main centre pedestals
D D, are bolted to the entablature immediately above the middle columns.
The steam-cylinder consists, as usual, of a separate casting from the valve-casing, which is joined to
the cylinder with red lead cement, both faces being previously planed and fitted; and has two packing-
ports c c, fitted with doors, which can be removed to admit of the packings on the back of the valve
being examined and renewed when necessary. The valve is of the long-D kind, and is worked by a
spindle passing through a tube at the lower end of the casing, and connected to a sliding stuffing-box 20,
which is provided with two projecting pins for connecting it to the links of the rocking-shaft v. This
shaft receives its motion from the eccentric t, upon the crank-shaft U, by means of the rod и.
The cold-water cistern N is placed, as usual, in the masonry of the foundation, and contains the
condenser K and air-pump M. These communicate by the passage L, in which is the foot-valve f,
opening towards the air-pump. The condenser is slightly conical in shape, and the upper and narrower
end is provided with an internal projecting collar, for the purpose of receiving the extremity of the
exhaust-pipe J, which being made tight with hemp packing, thus forms an expansion joint of the
simplest kind, and quite sufficient for the purpose. The lower end of the condenser enters slightly into
the passage L, through a hole cast in the upper surface of the latter, and is supported upon it by a
flange cast round the condenser for that purpose. The air-pump is attached to the foot-valve passage
in a similar manner, but projects downwards considerably more, for the purpose of giving the pump
a better hold of the water. The valve of the air-pump bucket g is of the perpendicular-lift, or pot-lid
kind, as is also the discharging valve h.
Action of the Engine.-To exemplify the action of the engine, let it be supposed that the throttle-
valve is open, and occupies a position parallel with the axis of the steam-pipe I, thereby allowing a
passage for the steam from the boiler to the valve-casing; although the piston is, in the present
instance, at half-stroke, still, on account of the lap of the valve, the steam cannot enter the cylinder to
start the engine, for both of the steam-ports e e are shut, as represented in the section. But the steam
being thus admitted into the valve-casing, if the blow-through-valve b be now open, (as shown,) the
steam will immediately flow into the condenser, and opening the foot-valve f, will expel the air, with
which we may suppose it to be filled, through the air-pump bucket and delivery valves. When the
air is expelled,-which is known to be the case as soon as pure steam is seen to issue from a small
valve, called the snifting-valve,the blow-through-valve is shut, and the injection-cock opened to admit
a shower of cold water from the cistern into the condenser, which, immediately condensing the steam in
the latter, and in the passage L, forms of course a vacuum in them. The rocking-shaft v must now be
moved by a portable lever which fits into a socket on the shaft, (seen in Fig. 892,) until the pin in the
fork of the working-lever comes beneath the gab of the eccentric-rod u; this motion will place the slide-
valve d in the proper position for opening a communication between the valve-casing and the lower
part of the cylinder, and between the upper part and the condenser. The atmospheric pressure being
thus in great measure removed by the expansion of the air above the piston, into the condenser, and the
steam being made to act upon the piston underneath, will cause motion of the piston in an upward
direction, which will be transmitted through the piston-rod o to the beam R, and thence by the con-
necting-rod S to the crank T, upon the fly-wheel shaft U. Motion being thus induced, when the piston
arrives at the end of its stroke, the momentum of the fly-wheel will carry the crank over the lower
centre, by which time the eccentric will have reversed the position of the slide-valve; a communication
will now be opened between the condenser and the lower part of the cylinder, and between the boiler
and the upper end, thereby producing a downward motion of the piston, and consequently continuous
revolution of the fly-wheel shaft. The injection water, together with that resulting from the con-
densation of the steam, meantime flows along the passage L, through the foot-valve f. and is pumped
away by the ai *-pump M, into the hot-well O, from which it flows back to the cold water reservoir.
It is also from the hot-well that the boiler is supplied with water, by means of the hot water or feed-
pump, shown in section in Fig. 891. The plunger of this pump receives its motion from the main beam,
to which it is attached by the rod s.-The inlet valve of the pump is connected by the horizontal pipe j,
with the hot-well, and through this pipe the water is drawn by the ascent of the plunger. which, in its
return stroke, discharges the water which had passed into the pump through the outlet valve at P, into
the supply pipe k. The supply of cold water is maintained in the cistern by the pump Q, which com-
municates with the cistern by the pipe m.
The governor W consists of a vertical spindle revolving in bearings within the column E, and is
driven by a pair of bevel-wheels from the fly-wheel shaft. The upper end of this spindle is hollow,
and, at that part upon which the sliding collar works, is slotted through to allow of a connection
between the collar and the rod, which passes down through it. The divergence or collapse of the balls,
as the engine moves with greater or less velocity, produces a vertical motion in this rod, which, by
means of a system of rods and levers z, is conveyed to the throttle-valve, and thus the speed of the
engine is regulated.
COG-WHEELS. See DETAILS OF ENGINES.
COINING MACHINE. This machine for stamping money was invented by M. Thonnelier, and com
bines economy with perfection of workmanship. durability of the machine, and safety to the operatives.
The moving power applied to a winch, or rather a steam power, turns я fly-wheel which governs it,
and sums up all its powers at the moment the piece is stamped. To the axle of this fly-wheel a spiral
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COINING MACHINE.
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Flz. 893, lateral elevation of the ma-
a lever G, fork-shaped, bearing the two
tremity an instrument to take the coin
chine.
balls H, hold the case against D. The
off, should it be attached to the supe-
A, principal axle turned by a winch
supporter and the lever of the case re-
rior.
or moving power.
volve round an axle in d.
This portion of the machine com-
B, connecting-rod giving to the lever
I, an iron lever receiving from an-
prises several pieces; viz. the side-
C the movement of the winch adapted
other lever concealed by the machine,
plates of the ferrule; the ferrule, &c.
to the axle A.
an impulsion transmitted by the eccen-
L, a tube which receives the metal
C, lever whose centre of movement
tric fixed to the plate o of the fly-
about to be coined.
is at a, in the interior of the cast-iron f
wheel N these two levers are fixed to
M, a passage through which the coin
P: it makes the second cylinder b re-
the axle J, which is the means of pla-
passes to fall into the basket.
volve the are of a circle.
cing the metal, and of drawing it off
N, fly-wheel.
D, a force column of steel. It moves
when stamped.
o, a cast-iron plate attached to the
at its lower part, in the box E. Its up-
i, a lath communicating with the
axle of the fly-wheel.
per portion is joined to the lever by
lever I, and destined to raise the point
P, cast-iron case of the machine.
the intervention of the steel cylin-
c on a level with the side-plate of the
QQ, four cast-iron columns giving
der b.
ferrule.
support to the frame of the machine
E, a sliding-case leaning against c.
e'. inferior stamp.
R, likewise made of cast-iron.
It is maintained by a double beam F;
K, placing hand. It has at its ex-
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COINING MACHINE.
curve is adapted to direct the movements of a connecting-rod, which transmits to the moving parts the
mechanism of placing and taking off the metal between the stamps, and withdrawing it from the ferrule
after the money is stamped.
The power accumulated by the fly-wheel, is transmitted through its axle to a winch, which acts upon
two arms joined to each other by a hinge at their extremities, and forming a very obtuse angle, which
can be opened or closed a little. When this angle is opened, the two other extremities of the arms or
levers become more distant, and as the superior meets a buttress, it is the inferior one which moves; it
is properly a funicular lever or mechanical knee. Thus the lower part of the inferior lever is drawn
towards it resisting plane, when the angle of the two arms widens, but on the contrary it is carried
away from the plane when the angle closes; the movements are produced by the connecting-rod and
the winch fixed to the fly-wheel.
The two stamps are placed, the one at the moveable end of the lever, above the metal to be coined
the other is situated beneath, the two planes being parallel.
The pieces to be coined are piled up in an iron cylindrical vessel, and at every turn of the fly-wheel, the
nether piece is taken away, and pushed under the press, being contained within a ferrule which limits its
circular diameter. When the lever rises, the coin spontaneously leaves the ferrule.
Cylinders.-The principle of this press consists in two cylinders having their axes parallel, and
turning in opposite directions.
These cylinders have on their outer surface engraved matrices, smooth and fluted ferrules, as well as
ferrules with inscriptions.
Fig. 900 presents a transversal section of the machine perpendicular to the axis of the cylinders.
Fig. 901 is a vertical section made through this axis.
The cylinder A receives the movement of the moving power; its axle has length enough out of the
case to have cogs B engaged into the pinion B', on the axle C. This axle has a fly-wheel C', and can
be set to work by any moving power through the pulleys D'.
The second cylinder A' is constructed almost like the first, and of equal diameter, having the same
number of matrices.
Two wheels E E' are connected with one of the extremities of the cylinders in order that they may
receive motion.
In the swollen centre of the second cylinder A', and on its surface, there are excavations to receive
the matrices a, Fig. 902 they are cylindrical metallic disks e support the matrices, whose distance
from the centre, or from the circumference of the cylinder, is thus governed. Buttresses b placed on
each side of the matrices are inserted into the cylinders, to push the matrices outwards. This forces
the iron out; which, when effected, the buttresses are sent back to their original position by the spring d.
At the central part of the outer surface of the cylinder A, grooves are made to receive the ferrule
matrices a', the form of which is hemispherical, Fig. 903, 80 that they can oscillate through the rotary
motion of the cylinders. The plane surface which terminates each matrice, and which is engraved,
passes through the centre of the sphere, but the outer circumference of this surface should be some-
what eccentric, to the surface of the sphere.
Pillows can be placed within the groove under the matrices; they are of steel, and can be regulated
by a screw. The matrices are by this means secured from oscillations.
Steel springs e, Fig. 900, act upon the sloped edges of the ferrule matrices, to forrce back these last
to the place they should occupy, as soon as they are no more opposite the matrices a.
A tube F. containing the pieces about to be coined, furnishes them to the matrices. The circumference
of the second cylinder A is surrounded with steel plates f, which have at their centre a cylindrical hole
of equal diameter with the matrices a; these plates serve to stamp the circumference of the coin.
When the cylinders are placed as represented in Fig. 900, the lowest piece in the tube F is in contact
with the surface of the plate; as soon as the matrice comes to the orifice of the tube, the piece falls
into the vacuum formed by the plate, and comes in contact with the engraved surface of the matrice.
The cylinder continuing its rotation brings the metal within reach of the ferrule matrice, and the coin is
stamped on both sides at once.
It is then pushed out of the matrice by b, assisted by the scraper g, which has a counterpoise.
The turning-pieces of the cylinders are received in pillows which allow them no lengthwise displace-
ment; and in order that the matrices may be retained in the same plane, perpendicular to the axis of the
cylinders, these are exactly clamped between the two cheek-pieces of the cases which contain their
pillows. Wedges pressed by screws h, hold the pillows firmly fixed. The coins, as they fall, receive no
shock, and are received in a box enclosed within J, the frame-work of the machine.
Such a machine coins more than 100 pieces in a minute, or 60,000 pieces in a day of 10 hours' continual
labor. The moving power required is but slight. This press performs its functions without noise, and
is not liable to be put out of order; its construction is simple, and it occupies little room. The work-
man who attends it is perfectly safe during his labor.
Should any accident or obstacle occur, the machine is so arranged that it stops spontaneously; the
fly-wheel C' is maintained on the axle by a species of break, Fig. 901, which allows it to turn back
without turning the axle, when a greater resistance than usual is experienced by the matrices, so that
the attendant is made aware of the accident.
New Method proposed by M. Béguin to stamp Money, Medals, and Jewelry.-This consists in placing
within the matrices a certain number of steel stamps. These matrices being piled one upon the other,
are enclosed in a rectangular box, and made to pass between two cylinders. This pressing is performed
rapidly, and many pieces are worked in a short while.
The stamps are placed within the matrices, and are of a slightly conical shape; in order that they
may be retained at the same level, a strong plate covers the matrices. A thin plate is interposed
between the two matrices, and is pierced with a number of holes equal to that of the stamps; its use
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COINING MACHINE.
289
is to keep the pieces to be stamped in connection with the stamps; this plate is made of steel, having
its surfaces even, and an equal thickness in all its points.
The system is carefully fixed into a rectangular frame, which is of iron, and holds the different
parts 80 firmly fixed, that they are not deranged while between the rolling cylinders.
B
F
A
900.
B
a
H
A
B
J
903.
B
B
901.
H
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902.
A
COLD WATER PUMP, content of. See DIMENSIONS OF ENGINES, and DETAILS OF ENGINES.
COLLECTING VESSELS: applicability of, to Locomotives. See MANAGEMENT OF ENGINES
COLLAR FOR PIPES, in boring. See RAILWAY ENGINEERING.
COMPARATIVE DIMENSIONS, of flue and tubular marine boilers. See BOILERS, VARIETIES OF.
37
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CONWAY TUBULAR BRIDGE.
CONDENSER, usually made of the same capacity as the air-pump, but the larger the better advantage
of high condenser to enable the air-pump to drain it. See DETAILS OF ENGINES. Disadvantage of put-
ting the main centre through the condenser.
CONDENSING AND HIGH-PRESSURE ENGINES, difference between. See VARIETIES OF THE
STEAM-ENGINE.
CONNECTING-CRANK This machinery, or apparatus, for connecting two shafts so as to cause
the same to revolve at different velocities, is illustrated somewhat in the following manner:-
Let a b, Fig. 904, represent the pitch-
906.
line of two wheels, the wheel a being
twice the diameter of the wheel b; then
for every revolution of the wheel a, the
c
wheel b will make two revolutions, and
if a tracing point be attached at b', it
g
d
will describe the straight line a a' upon
the face of the larger wheel, and if an-
I
a
other tracing point be attached at the
opposite side of the small wheel b, such
points will describe straight lines at right
angles to one another during the revolu-
tion of such wheels.
In Fig. 904, is shown an elevation of
the arrangement of levers for connecting
two shafts together, so that they may re-
volve at different velocities. Fig. 905, is
a plan of one of the shafts which is pro-
vided with a crank forming a portion of
904.
the apparatus. In Fig. 906, a is a crank,
905.
fixed upon the end of a shaft b, supported
by suitable bearings; c is the crank-pin
which supports the triangular arm d,
through each end of which there are pins
e e, in the same plane with the aforesaid
shaft these pins support two connecting-
f
a
rods f g, the lower end of the connecting-
rod f being attached to the crank f',
shown in the plan, the lower end of the
k
connecting-rod g being attached to the
crank-pin g' of the plan; b is a pin fixed
into the end of the shaft which carries
one end of the connecting-link i, the oppo-
site end being attached to the centre, or
middle of the connecting-rod e, by the
b
pinj ; k is the axis of the shaft which is
to receive motion from the shaft b, or
vice versa ; consequently, if g be double
the length of the connecting-link i, the
point g' will describe a straight line 11, and if we suppose g to be attached at its lower end to the crank-
pin g'. and also the rod f to the crank-pin f', and that the axes b and k revolve in suitable bearings,
Ic will make two revolutions whilst b makes one revolution.
There are other modifications of the above apparatus shown, for which the inventor claims machinery
described for connecting axes or shafts, to revolve in connection at different velocities.
CONWAY TUBULAR BRIDGE. The great engineering event for 1848 is the raising of the
Conway Tubular Bridge, and which, after so much fear and anxiety, has been effected with great
success. This work derives its importance not so much from its greatness, as from its opening the way
for the adoption of a new system of bridge building, whereby the resources of engineering are very much
extended. To build a bridge greater than those which have been made before, to make a railway
longer than those which have yet been opened, or to construct a more powerful locomotive, is a great
work; but it is of much greater importance to execute something entirely new. The engineer who has
constructed the greatest lighthouse or the greatest dock in his day, may be overcome by some one else,
and then his claim is at an end; whereas, the engineer who extends the resources of his art, has a clear
and unique claim to distinction. Mr. Robert Stephenson has the merit of carrying out this system of
tubular bridge building, and it will be a special event in his career, beyond the many works of con-
structive skill he has already produced. The success of the Conway Bridge is none the less important,
because it settles the practicability of that greater undertaking, the Menai Tubular Bridge. Thus
progress in any one direction leads most certainly to greater exertion; and it is peculiarly necessary to
give every encouragement to all attempts, which open a new career for the engineer, and give him
greater means of exertion.
We have thus given engravings of the tube and the lifting apparatus, and shall lay before our readers
drawings of the ingenious Jacquard machinery, invented by Messrs. Roberts, for punching the plates.
(See Jacquard Punching Machine.)
The construction, when finished, is to consist of two tubular bridges, formed of wrought-iron plates,
each tube being for one line of rails. We shall now confine ourselves to the description of one of the
tubes, which was fixed in its place in March, 1847, and is shown in the accompanying engravings.
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CONWAY TUBULAR BRIDGE.
291
Fig. 907 exhibits a transverse section of one of the tubes and the masonry of the pier, together with
the lifting apparatus. Fig. 908 is a side elevation of 19 feet in length of the tube, resting on the
masonry, and the lifting apparatus. Fig. 909 is a section through 12 feet in length of the tube, and
section of the lifting apparatus. Fig. 910 is a plan of
the top of the tube to the extent of 20 feet in length,
910.
and plan of the hydraulic press. Fig. 911 is a front
view of one end of the suspension girder, and Fig. 912
a side view.
The tube consists of a shell or external casing, a a,
of wrought-iron plates, from 4 to 8 feet long, and 2 feet
wide by half an inch thick in the centre, and five-
eighths of an inch thick towards the end of the tube,
riveted together to T-angle-iron ribs, placed on both
sides of the joints, and angle-gussets at the feet of the
ribs to stiffen them; a ceiling, composed of 8 cellular
tubes b, each 204 inches wide, and 21 high; and a floor
containing 6 cellular tubes c, 271 inches wide, and 21
inches high. The whole length of the tube is 412 feet,
and 22 feet sh inches high at the ends, and 25 feet 6
In
m
inches high in the centre, including the cellular tubes
F
at the top and bottom, running the whole length, and
14 feet wide to the outside of the side-plates. The
upper cells are formed of wrought-iron plates, three-
fourths of an inch thick in the middle, and half an inch
thick towards the ends of the tube, put together with
m
m
angle-iron in each angle of the cells; and over the
upper joints is riveted a slip of half-inch iron, 41
inches wide. The lower cells consist of three-quarter-
inch iron plates for the divisions, and the top and bot-
tom of two thicknesses of plates, each 12 feet long, 2
feet 4 inches broad, and half an inch thick in the centre,
and one-fourth of an inch thick at the ends, and 80
arranged as to break joint; and a covering plate of half-inch iron, 3 feet long, is placed over every joint
on the underside of the tube. The external casing is united to the top and bottom cells by angle-iron,
on both the inside and outside of the tube, as shown in Fig. 912.
The ends of the tube, where it rests on the masonry, are strengthened by cast-iron frames d, to the
extent of 8 feet of the lower cells; 6 cast-iron transverse I-shaped girders e, on the floor; 6 similar
girders f, above; and upright cast-iron stanchions g, on each side of the tube, to which are bolted the
ends of the girders, top and bottom, and also the cross-lifting girders h.
In order to allow of the free expansion and contraction of the tube, the ends rest on 24 pairs of iron
rollers i, connected together by a wrought-iron frame, and placed between two cast-iron plates j k, 12
feet long by 6 feet wide, and 4 inches thick. The lower plate is laid on a flooring of three-inch planks i,
bedded on the stonework; and the tube is also suspended to 6 cast-iron beams m, the ends resting on
longitudinal bearers n, 12 feet long, with a circular groove on the under side, supported by 12 gun-
metal balls o, 6 inches diameter, standing upon an iron bed p, and supported on the ends of the cast-iron
bearers q. The tubes are suspended to the beam m, by wrought-iron bolts r, and spade-pieces riveted
on to the sides of the tube, as shown in Figs. 911 and 912.
The lifting apparatus for raising this enormous weight was intrusted by Mr. Stephenson, to Messrs.
Easton and Amos, engineers of the Grove, Southwark, to whom great credit is due for the very
successful manner the tube was lifted. The machinery consisted of two steam-engines, erected in the
recesses B of the corresponding tube, one on each side of the river; and each engine has a horizontal
cylinder, 17 inches diameter and 16 inches stroke, with piston-rods working through stuffing-boxes at
each end of the cylinder; each piston-rod has a cross-head, and gives motion by side-rods and cranks to
two fly-wheels; and the ends of the two piston-rods work two forcing-pumps with plungers, 111/7 inch
diameter, and 16 inches stroke. These pumps inject the water into the hydraulic press C, shown in the
engraving, through the small tube 3.
The press was erected on a stage constructed above the level of the top of the tube, and consisted of
two cross-girders of cast-iron, each in two heights D, D', the lower one 4 feet high, and the upper one
2 feet 6 inches high; the ends resting upon cast-iron bearers E, imbedded in the masonry of the piers.
Upon the cross-girders was fixed the casing F of the ram, which is 5 feet 2 inches long, by 3 feet 9
inches wide, cast with ribs; and on the top of the cylinder are fixed two vertical guide-rods G, G, 6
inches diameter, passing upwards through the cross-head of the ram, and a cast-iron girder H, nearly at
the top of the tower, and 18 feet above the girders D'.
The press consists of a cylinder, 1, firmly fixed in the casing, 371 inches diameter externally, and
20 inches internally; and the ram 2, 18} inches diameter, with a vacuity nearly seven-eighths of an
inch all round, to receive the water injected from the pumps already described, through the tube 3,
the orifice of which is three-eighths of an inch diameter; this tube is furnished with a lever-valve close
to the cylinder, for safety, in case the pipes should burst. In the event of such a casualty, by an
ingenious contrivance the lever-valve would be instantly closed, and the weight supported by the water
in the cylinder. On the top of the ram is a cross-head 4, of solid castiron, 9 feet 10 inches long, 1 foot
10 inches deep, and 2 feet 4 inches thick, with two apertures, 2 feet 1 inch long, by 1 foot 11 inch wide,
through which the lifting chains pass: and on the top of this cross-head are fixed two clipping vices or
clams, 5, 5, each consisting of & pair of wrought-iron jaws, 3 feet long, 11 inches deep, and 6 inches thick,
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CONWAY TUBULAR BRIDGE.
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COP-SPINNER.
and a winch which turns a small pinion 6, that takes into two cog-wheels 7, 7', fixed upon the heads of
two horizontal screws, (8, 8', left and right handed,) passing through nuts in the two jaws of the clams.
Thus it will be perceived, that as the winch is turned, the jaws are made to open or close, for the
purpose of clipping the heads of the lifting chains; below these clams are two others 9, 9', for clipping
the heads of the lower links.
The two lifting chains consist of wrought-iron flat bars, in lengths of 6 feet from centre of bolt-eye to
entre, and each bar is 7 inches wide and 11, 11,
and 11 inch thick, with heads having shoulders
911.
fitted to the jaws of the clams. Each chain
contained nine links of eight and nine bars
alternately, besides the two lower links, each
consisting of five and four bars. The heads of
the first or upper links passed through the
m
m
m
upper lifting clams, fixed on the top of the cross-
head of the ram, and there secured by the jaws
of the clams being screwed up taut; the second
links passed through the lower clam, the jaws
n
of which were left open, and the heads of the
two lower links were made to abut against the
O
under side of the lifting girders g h. When the
pumps were set to work, the ram was lifted 6
feet, its full range; when it had attained this
elevation the jaws of the lower clams 9, 9' were
screwed up close and clipped the heads of the
912.
T
third links 11, and there held the chain firm;
the jaws of the upper clams were then opened,
and the ram lowered down to its original posi-
tion, when the bars of the top links 10 were
m
removed. When this had been done, the jaws
of the upper clams 5, 5' were again brought
under the heads of the second links, and screwed
up taut, so as firmly to clip the shoulders of the
links, the jaws of the lower vice 9, 9' opened,
and the ram was then set in motion to lift the
tube another six feet, when the second links
were removed as before described, and the
b
operation repeated as above, until the tube had
been lifted the height required, about 22 feet to
24 feet.
The power of the presses may be thus cal-
q
culated: the area of the ram being equal to
337.64 circular inches, and the force acting upon
the plunger equal to 2.14 tons per circular inch,
the two being multiplied together give 7221
tons, which is the force of one of the presses, and
of the two presses 1445 tons. The actual weight
lifted was estimated at 1,300 tons. The quantity
of water used for each press is about 66 gallons.
The tube was constructed on a platform erected on the shore of the river, close to where it was to
cross and when finished, six pontoons, something similar to the large coal-lighters on the river Thames,
were placed under the tube at low water, and which at high water lifted the tube off the piles upon
which the stage was erected. It was then floated to its destination, and placed between the two
towers, part of the masonry being left undone until the tube was put into its proper position, and as it
was raised the masonry was built up under the tube. The time occupied in raising the tube and building
up the masonry occupied four days; the actual space lifted per hour was 13 feet.
COP-SPINNER. George H. Dodye's Improvements in Machinery for Spinning and Winding
Yarn-This is a combination of the self acting mule and throstle, and has many advantages over the
common method of spinning, and is equally applicable for filling and warp yarn. In the room usually
occupied for 1,000 mule spindles, 1,500 may be placed, which will do the work of 3,000 spindles. It
occupies the usual space required for warp spinning, but will spin 50 per cent. more yarn to the spindle
than the best ring-bobbin spinning known to us in use, and with a saving of two-fifths of the power. It
will spin 100 per cent. more yarn than the flyer spindle, and with one-half the power, compared to the
quantity. There is a great saving in expense, by dispensing with bobbins. The spindle is more durable
than the common one in use, being tapered to the top; and there being no bobbins or check-pins used,
it maintains its balance at any speed required. It is not liable to get out of order. It is much more
convenient to piece up the ends when broken, than the bobbin-frame. One cent per spindle is paid for
tending warp-frames. and 1f cent for filling-frames, and twelve dollars extra for doffers, per week. The
proprietors, Messrs. John C. Dodge & Sons, of Dodgeville, Attleborough, Mass., have their entire mill
upon this method of spinning, and from 29 years' practical experience with other spinning, believe it to
be the best in use.
The following table exhibits the comparative product and cost of their old plan of spinning with that
of their present improved cop-spinner:-
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COP-SPINNER.
295
Bobbin throstles and mules, 4,600 spindles.
1847, 19 weeks product
25,775 lbs. warp,
23,831
"
filling,
cost, $1,116 69
u
25,974
"
1848,
"
u
warp,
"
24,523
"
filling,
1,051 78
2)100,103
2)2,168 47
Average,
"
"
"
50,051$
"
"
$1,084 23
Cop-spinner, 2,320 spindles.
1849, 19 weeks product
32,704 lbs. warp,
28,5741
"
filling,
61,278₫ " at a cost of $845 50.
The yarn was No. 30, and the average skeins per spindle daily, was seven, no allowance being made
for stoppage.
The specification of the patent states, that the peculiar object of the improvements which are applied to
a throstle spinning-frame, is to wind the yarn, as fast as twisted, or when properly twisted, upon each
of the spindles in a regular or proper shaped cop, which shall have a binding-thread between each two
adjacent layers of yarn, in order to prevent the cop from falling apart when removed, or while being
removed from the spindle.
Fig. 913 exhibits a front elevation of the improved throstle-frame. Fig. 914 is an end elevation. Fig.
915 is a horizontal section, taken through the axis of the main drum, which drives the spindles and
scroll-shaft; the other parts below the plane of the section being represented in top view. Fig. 916 is a
rear elevation of the frame, with the exception of those parts of the mechanism which are situated
above the tops of the spindles, and which are like those'in common use in throstle-frames. Fig. 917 is
a vertical section of the scroll-shaft and parts connected with it.
In the several figures, A A denote the cast-iron ends of a throstle-frame; B B are the step-rails of
the spindles; C C, the upper bearing rails of the spindles; D D D, &c., are the spindles; E, the main
drum by which they are driven; F, on each side of the frame, is the copping or ring-rail; G G, &c, are the
guides to the threads in their passage from the front pair of drawing-rollers to the spindles; H is a
series of drawing-rollers, such as are in use in other throstle-frames; I is the bobbin-frame or creel; K
is the main driving-shaft, from which the drawing-rollers and other parts receive their motions; L is
termed the scroll-shaft-it is situated beneath the main shaft, and extends transversely across the
machine, and revolves in bearings a a, fastened to the step-rails B B. It is also supported by, and
revolves in, a third box or bearing b, secured to a sustaining bar c, ends of which are respectively
fastened to one end A of the main frame, and a transverse beam d extending from one lower girt e, on
one side of the frame, to the other f.
The scroll-shaft has a reciprocating partial rotary motion imparted to it; it being made to move first
in one direction, viz. forwards, with a slow motion, and next in the other direction or backwards, with
a much faster one.
A dog or clutch wheel g is fixed upon a hollow shaft It, made to run loosely upon the scroll-shaft, in
the position as seen in Figs. 915 and 917. The said shaft h has a worm-geer i fixed upon it, which is
made to engage with an endless screw or worm k, attached to the lower end of a vertical shaft l, sup-
ported by and made to revolve in suitable bearings. On the upper part of the said shaft 1 is a spur-
geer m fixed upon it, which is made to engage with, and is turned by a pinion n, fixed on another
vertical shaft o: see Fig. 914. The said shaft 0 turns in proper bearings and has a spur-geer p fixed
upon it, which geer is made to engage with a spur-geer q fixed upon a third vertical shaft r, put in
motion by two bevelled wheels s t, the former of which is placed upon it, and the latter upon the main
driving-shaft k. Consequently, when the main shaft is put in revolution in the direction denoted by the
arrow u, in Fig. 914, motion will be given to the clutch or dog wheel g, in the direction denoted by the
arrow v.
The clutch-wheel g consists of a circular plate, having a series of projections w w, &c., disposed at
equal distances, as seen in Fig. 918, which is a side elevation of the dog-wheel, as removed from the
scroll-shaft.
The teeth w w, &c., project over the periphery of a circular plate y, which is fixed upon a hollow
tube b', screwed to the scroll-shaft, and has a recess z cut in it, (as seen in Fig. 919, which is a side view
of the plate y,) for the reception of a spring-dog a', the spring of which is secured to the hollow hub b'.
A bent lever c' is made to turn upon a screw-pin d', inserted in the face of the plate y. The said lever
should be so curved as to rest against the spring of the dog a', and when its outer end is elevated, to
press against the spring of the dog, and move it and the dog inwards, or out of one of the spaces x
of the dog-wheel and into its recess 2. A standard e' is fixed to the side of the frame for the lever s'
to rest on.
From the above it will be seen, that while the dog remains in any one of the spaces x x, &c, of the
dog-wheel, the said dog-wheel will be so clutched to the scroll-shaft as to put the shaft in motion when
the dog-wheel is rotated. When thus put in motion the shaft will continue to move until the lever c' is
so borne against the stud e' as to press the spring-dog inwards, and out of the space x, in which it may
happen to be.
The scroll-shaft will be then unclutched from the dog-wheel, and left free to move in an opposite
direction, and will drag the spring-dog around with it until it meets the succeeding notch x, and springs
into it, and by so doing, again clutches the dog-wheel to the scroll-shaft.
On the scroll-shaft is a cam or scroll f', Fig. 920, made to move freely on the shaft. This cam has a
chain g' attached to it, Figs. 920 and 915. The chain is carried horizontally over a guide-pulley h', and
thence downwards, and is connected to an arm i', which projects from a horizontal transverse rocker.
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296
COP-SPINNER.
shaft k'. A similar transverse rocker-shaft l' is arranged parallel to the shaft k'. From each of the
shafts h' l' an arm m' extends upwards, and is jointed to a horizontal connecting-rod n'. Each of these
shafts has also two other arms o' o', or p'p', extending from it, Fig. 915. To each of these last-men-
tioned arms one of four vertical rods q' q'q' q' is jointed. Each ring-rail F is indirectly supported on
two of the rods q' q'; that is to say, small studs r' r', from its vertical guide-rods s' 8', rest upon the
tops of said rods.
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From the above it will be seen, that when the chain g' is drawn forward, or in a direction towards the
right-hand end of the main frame, each ring-rail will be raised upwards. So when the chain is suffered
to move backwards, the ring-rails will be left free to fall down by their own weight. The scroll f is
fixed upon a hollow shaft t', which revolves freely on the scroll-shaft L. A worm-geer 26' is fixed on
the said hollow shaft t', and engages with an endless screw v', fixed on a shaft 20', which revolves in
bearings in the tops of a frame x' which is fastened firmly to the scroll-shaft L. The said shaft 20' has
a ratchet-wheel y fastened upon its forward end.
The shaft 20' extends through one end of a vibrating lever a⁸, which is made to play loosely upon the
shaft. The said lever carries upon its other end an impelling pawl b², which engages with the ratchet-
whecl Over the ratchet-wheel is a retaining pawl c2, which is jointed to an arm d' extending upwards
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COP-SPINNER.
297
from the frame x'. The ratchet-wheel y' has a small crank-handle b' projecting from its side to turn
the whole back and lower the ring-rail when the pawls are thrown up, and when desirable.
Directly under the rear end of the lever a² is a
bent lever e⁹, which turns upon the scroll-shaft as a
fulcrum. Its outer end rests, when in its lowest po-
sition, on the top of a stationary standard f2, affixed
to the lower girt of the cast-iron end of the main
frame. The inner arm of the said lever 2 extends
917.
directly under a horizontal projection g² applied to
a vertical rod h², extending downwards from the
adjacent ring-rail F. The said projection gª should
be so adapted to the rod h² that it may be elevated
or depressed by adjusting-screws and nuts, in order
that its position may be regulated as circumstances
F
may require.
The scroll-shaft has a cam i2 fixed firmly to it.
The said cam is seen in Fig. 921, which represents
a section of it, and the lever beneath it. It also
exhibits the chain g', and various parts adjacent
thereto. The cam i' is made to act upon and depress a lever k², whose fulcrum is at P. The said lever
carries a roll m², applied to the side of its inner end, and resting on the chain g³.
Now in order that the ring-rail may not fall so suddenly as to break the yarns, or not put on the cop
a sufficient quantity of binding-thread, some kind of mechanism becomes necessary to cause it to fall
with the required velocity.
915.
D
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Уг
m
SCALE.-1 foot=1 inch.
A
A
An arm n², fixed to the scroll-shaft L projects downwards from it, and carries a small fly-wheel 02 on
an axle p', extending horizontally from it. Said fly-wheel has a small pinion q2 affixed to it, which engages
with a spur-geer 73 fixed to a tubular shaft 5², which runs loosely upon the scroll-shaft. On the said shaft 82
is a worm-geer t² which engages with an endless screw u², placed on the vertical shaft o, before men-
tioned. The said endless screw u² should 80 revolve the geer-wheel t2 as to turn the shaft 8² and the
geer-wheel nº in the direction of the arrow on said wheel r³.
The wheel 73 will then act on the pinion, and put the fly-wheel 02 in rapid revolution in the direction of
the arrow; this taking place while the ring-rail is being raised, will cause a considerable momentum to
be generated in the fly-wheel, which rises upwards with the arm n³, which will be carried up by the
forward movement of the scroll-shaft. Now when the ring-rail falls, the momeutum so generated in the
fly-whoel will be brought into action in such manner as to cause the pinion q2 to so operate against its
geer 7ˢ, as to counterbalance in a certain degree the tendency of the ring-rail to fall too suddenly. The
ring-rail will thus be eased down, so as not to break the threads, and with the degree of velocity necessary
to insure the laying of a due quantity of binding-thread on the cops.
The ring-rail may be further counterbalanced by an adjustable weight v³, applied to an arm 202 ex-
tending from the rocker-shaft k'.
By means of the scroll f', the length of each successive layer of yarn composing the cop is regulated.
The elevation of the ring-rail is gradually increased by the peculiar shape given to the scroll f', and the
gradually turning said cam on the shaft.
Fig. 922 represents a longitudinal and central section of a cop, placed on a spindle 1. The part a be
def of the cop, is termed the bottom part, and all above, the top part. The first layer of yarn is wound
on the spindle a distance an, equal to about one half of the length b c of the last layer composing the
bottom part of the cop. From the above, it will readily be understood why the scroll or cam f' must
be gradually turned on the scroll-shaft, so as to increase the length of each successive layer of yarn
composing the bottom part of the cop.
It is the purpose of the worm u', endless screw t', shaft 20', frame x', ratchet-wheel y, vibrating lever
38
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COP-SPINNER.
a², impelling pawl bª, lever e2, standard f2, projection g², and rod h², as before described, to produce
the gradual rotation of the cam, both to form the bottom and top part of the cop. When the scroll-
shaft is moved forward, the lever a² will be moved against the lever e2, and thereby cause the impell-
ing pawl b², to turn the ratchet-wheel y' a short distance, 80 as to create a movement of the scroll or
cam f' on the scroll-shaft. The movement of the ratchet-wheel is increased by elevating the outer
end of the lever e², which may be effected by depressing the adjustable projection gª of the rod h².
Owing to the manner in which the scroll f' is made, it becomes necessary to turn it somewhat faster on
the scroll-shaft at first, while forming the lower portion of the bottom part of the cop, than it does as
the winding of the said bottom part continues to progress. In winding the top part of the cop, the
scroll has a regular progressive motion upon its scroll-shaft, and the portion b c d, Fig. 920, of its peri-
phery is then receiving and acting on the chain g'; while the bottom part of the cop is being made, the
portion a b, Fig. 920. is in action upon the chain.
In order to cause the ring-rail to rise upwards with the increased velocity necessary to prevent the yarn
from piling too much in one place, aid thereby destroying the conical form of each layer of yarn, the
cam i², lever k², and roll m², are used, the cam being 80 formed as to properly depress the lever kª,
to the extent required, to cause the roll m² to bear down upon the chain g', so as to produce the gradual
increased rise of the ring-rail
922.
3
919.
h
L
c
I
921.
a
918.
916.
2
D
D
6
D
IS
A
Vª
q
SCALE.-1 foot=1 inch.
As it is very important that but very little yarn should be wound at the nose or upper part of each
layer of the cop, the cam i² has an angular projection x². (see Fig. 921,) which as soon as the cam has
completed its action in the lever h², shall in its turn depress the lever so as to cause a very sudden rise
of the ring-rail sufficient to produce the effect required. A friction-spring 1/2, at the end A of the main
frame, acts as a stop to gradually check the motion of the arm n², when it falls down.
It often happens that the ring of the ring-rail may render it difficult to get hold of the end of the
thread wound on the cop. In order to overcome this difficulty, the spindle, for about one inch and a
half below its upper bearing, is made of the same size or diameter as the part which runs in the bear-
ing, as seen at 2ˢ, in Figs. 913 and 922.
By taking hold of the spindle when so made, it may be readily raised upwards, so as to carry the
broken end of the thread above the ring of the ring-rail, and into such a position as will readily enable
the operative to join the ends of the yarn when broken.
In order to obtain the advantages of a small spindle, and with a diameter at bottom large enough to
start the traveller without danger of rupture of the yarn, the part a³ of the spindle directly below
that on which the cop is formed, is made of a diameter large enough to produce the lateral drag upon
the traveller, required to overcome its inertia when first started, and give to it a velocity that will pre-
vent the thread from breaking; and, before commencing the cop, a few turns of yarn are wound on the
said part of the spindle. That part of the spindle on which the cop is formed, (viz. the part 63 c³,) is
made of as small a size as will be allowable and admit of its possessing the necessary strength.
The spindle 80 constructed is seen in the drawings. By this mode of making it, cops can be doffed
without first being obliged to raise them upwards on the spindles by the hand far enough to allow of a
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299
few turns of yarn to be laid on that part of each spindle on which the cop is first commenced, as is
generally done in mule spinning.
A convenient velocity for the spur-geer rˢ, is one revolution to sixteen of the front drawing-roller;
and for the clutch g, at the rate of sixty-four one-hundredths of a revolution to eighty revolutions of the
front drawing-roller. The patentee mentions these proportions, but does not confine his invention to such.
Mr. Dodge claims the combination of mechanism by which the scroll-shaft has a partial rotary for-
ward motion imparted to it, and is allowed to fall or move backwards, the same consisting of the stand-
ard e¹, or any equivalent, the bent lever c', the spring-dog a¹, the clutch or dog wheel g, or their me-
chanical substitutes; the whole being arranged, applied to the scroll-shaft, and operated and made to
operate together substantially. And in combination with the shaft, and machinery for imparting to it
its rotative motion or motions, he claims the cam, and chain, and machinery connecting the shaft with
the ring-rails. He further claims the combination of mechanism by which he is enabled to regulate the
length of each successive layer of yarn composing the cop; the same consisting of the cam f¹, and made
to rotate on the scroll-shaft; the worm-geer u', endless screw t', shaft w', frame x', ratchet-wheel y',
vibrating lever a², impelling pawl b⁹, lever e³, standard f2, projection g², and rod h², extending down-
wards from the ring-rail, or their mechanical equivalents; the whole being combined and made to operate.
Further, in its application to the scroll-shaft, the combination of mechanism by which the fall of the
ring-rail is regulated in such a manner as to prevent it from descending too suddenly so as to break any
of the yarns; the mechanism consisting of the fly-wheel o², and machinery for turning it, as applied to
the scroll-shaft, and made to operate in connection with it. And for the purpose of causing the ring-rail
to rise upwards with the increased velocity necessary to prevent the yarn from piling too much in any
one place, and thereby destroying the conical form of such layer of yarn composing the cop, Mr. Dodge
claims the cam i², lever k², and roll m², as combined with the scroll-shaft, and the chain g'. And in
combination with the machinery, he claims the projection x3, applied to the cam is, for the purpose of
producing a very quick rise of the ring-rail, in order to finish the nose or upper extremity of each layer
of yarn composing the cop. And he also claims the above-described manner of making each of the
spindles, in order that it may be elevated so as to carry a broken end of yarn above the ring-rail, so that
an attendant may readily seize it to piece up or join it to the thread proceeding from the draw-rollers,
without being obliged to wait for the ring-rail to full downwards.
He further claims the construction of the spindle directly beneath that part of it on which the cop is
formed of a diameter proper to produce the lateral drag on the traveller, sufficient to overcome its in-
ertia, and impart to it a velocity necessary to prevent the yarn from being broken in combination with
making that part of the spindle on which the cop is formed smaller in diameter.
COPPER BOILERS, Faults of. See BOILERS.
CORNISH BOILERS. See BOILERS.
CORNISH ENGINE, Causes of the economy of-See BOILERS. Structure of-See VARIETIES OF THE
STEAM-ENGINE. Particulars of, Performances of-See DETAILS OF ENGINES. Lantern brass to cover
the cylinders of-See DETAILS OF ENGINES.
CORN-MILL By William Fairbairn, Manchester. Among the mechanicians who have contributed
to the improvement of that description of machinery now under consideration, Mr. Fairbairn, of Man-
chester, occupies a most distinguished position, and accordingly, we find that he is most extensively em-
ployed in the erection of corn-mills throughout all parts of the continent of Europe. The exam-
ple which we have chosen for detailed illustration is a small mill of three pairs of stones, erected by
him for His Excellency the Seraskier Halil Pacha, of Constantinople. It is interesting, as exhibiting,
within a small compass, an epitome of all the processes carried on in larger establishments, and thereby
enabling us to show the mechanism by which these processes are effected on a larger scale than we
could otherwise do.
Enumeration of the Figures.-Fig. 923 is a sectional elevation of the mill, the line of section being
taken in a longitudinal direction, and exhibiting the position of the stones, the engine, and driving geer-
ing, and of such portions of the subordinate apparatus as are visible on the side of the mill which is
exposed to view.
Fig. 924 is a sectional plan corresponding to the above, and taken on a horizontal line passing through
the lower story of the mill.
Fig. 925 is a transverse section of the entire mill, in which are shown the garners for undressed and
dressed wheat, the mechanism by which it is cleaned and conveyed from the former into the latter, the
sack-tackle, &c.
Fig. 926 is a sectional plan corresponding with the plan Fig. 924, the line of section being taken
through the second story of the mill.
General Description.-The house in which this mill is contained consists of an assemblage of plates
of sheet-iron, A A A, of a suitable thickness, consolidated and bound together by the cast-iron columns
B BB, and by the strong cast-iron girders CCC, situated at such a height as to oppose and neutralize
the strain of the principal working parts. It is surmounted by an arched roof DD, formed of plates of
corrugated sheet-iron. A wall of masonry EE is erected in the interior, for the purpose of affording a
foundation for the bearings of the heavier geering of the mill. The motive power is supplied by a high-
pressure steam-engine F, of 12-horse power, its principal working parts are wholly inclosed within
a large cast-iron column. By this arrangement great firmness and stability is imparted to the engine,
while the space which it occupies is reduced to the smallest possible dimensions. The boilers GG are
situated in an adjoining part of the house, and their flues H H are formed, in the usual manner, of brick-
work, abutting on the one hand against the wall E, and on the other against the side of the house itself.
Thus the engine and boilers occupy nearly the entire half of the lower story of the mill. The whole
erection is strengtheued and bound together by the cast-iron beams III, which pass transversely
through the interior of the house, and are supported, in the middle of their length, by the columns J J.
On these beams, also, the flooring of the lower and upper flats is disposed.
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CORN-MILL.
The fly-wheel KK of the steam-engine, is formed with teeth on the exterior of the rim, thus serving
at once to regulate the velocity and to transmit the power of the steam-engine to which they are at-
tached. The spur fly-wheel KK, the diameter of which is 9 feet 34 inches, geers with the pinion L of
4 feet 10} inches diameter; consequently, the velocity of the crank-shaft is nearly doubled upon the
horizontal shaft MM, to which the latter is fixed, and which, by means of the bevel wheels and pinions
N NN, gives motion to the stones contained within the stone-cases PPP. The shaft MM has a bear-
ing upon the wall E, close to the back of the pinion L, and one in each of the standards 000, to which
the mechanism necessary for impelling and regulating the action of the stones is attached.
N
a
I
B
923.
a
B
SCALE.-20 feet=3 inches.
The corn to be ground is deposited in the upper floor of the mill in the large garner QQ, from which
it is conducted through the spout R, into the acreening-machine SS, where it is cleansed of the dust
and other extraneous matter which is found more or less combined with it. This machine consists of a
species of cylindrical sieve, formed of wire-cloth, and partitioned inside 80 as to resemble an Archime-
dean screw. It is mounted upon an axis, and revolves with a considerable velocity in the interior of a
close box, in which it is set at an angle with the horizon. The corn enters at its upper extremity, and,
after being thoroughly agitated by its passage through the partitions in the interior of the screen, and
thereby divested of the greater portion of the refuse with which it was mixed, falls into a spout U, at
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301
its lower end, which conducts it to the elevator V; being subjected, in its passage through this spout, to
the action of a blast from the fan T, by which the remaining portion of the sand and dust that escapes
with the grain is carried off by a passage leading to the exterior of the house. The grain, after being.
thus cleansed, is caught up by the elevator V, and raised nearly to the summit of the mill, where it is
delivered, through an inclined spout X, into the creeper-box YY, by which it is distributed into the
feeding-garners ZZZ
924.
SCALE.-20 feet=3 inches.
R
M
K
-
H
The elevator consists of a long endless chain of small buckets formed of tin-plate and mounted, at
regular distances, upon a leather band passing over two pulleys inclosed within the cast-iron frames
VV. The uppermost of these pulleys is driven at a moderate velocity by a belt, and the buckets,
passing in succession the opening by which the grain is delivered from the screen, become each charged
with a small portion of it; this they convey through the wooden pipes or boxes W W, in which they
are inclosed, to the upper extremity of the chain, where they deliver their contents into the spout X.
The contrivance just described is applicable only to the raising of the grain or flour from a lower
level to a higher. For horizontal transport, modern millwrights make use of an apparatus called the
creeper, a long endless screw with a wide pitch and thin threads, inclosed in a wooden box or trough,
of dimensions slightly greater than its own diameter. It is made to revolve upon its axis, by means of
a belt and pulleys, at a velocity corresponding with that of the elevators, and, being restricted from
moving longitudinally, the threads, or rather leaves, of the screw, force the grain introduced at one end
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CORN-MILL.
of the trough to the other. The action of the screw in the case of the creeper is identical in its nature
with that of the endless screw in giving motion to a worm-wheel.
The corn which is supplied to the garners ZZZ, falls through the feeding pipes A' A' A', into the
hoppers, by which the grinding apparatus is surmounted. After being reduced into flour, it falls
through the pipes B' B' B', into the creeper-box Y' Y'Y', by which it is transferred to the elevator V.-
By this elevator it is again raised to the summit of the house, and carried by means of the creeper Y'
to the dressing-machine S'. It may be remarked that, besides the great saving in manual labor effected
by the use of these contrivances for transporting the flour from one part of the mill to another, they
are attended by another very important advantage: by exposing the flour liberally to contact with the
air, the heat evolved during the process of grinding is abstracted, and the moisture evaporated; an
operation which it is of essential importance that it should undergo previous to the process of dressing.
5
925.
as
Q
I
$
A
U
P
C
I
B
If
SCALE.-20 feet=3 inches.
This machine, which is very similar in external appearance to the screening-machine already de-
scribed, consists of a hollow cylinder covered with wire-cloth of different degrees of fineness, the finest
being at the end which is most elevated. Within the cylinder, which is stationary, a circular brush re-
volves, in contact with the wire-cloth of which it is composed. The flour which is fed into the cylinder
is, by the motion of the brush, sifted or rubbed through the wire, the finest through the upper end, the
second through the next division, and so on, till the bran falls through the end of the cylinder, being too
coarse to pass through any of the wires.* The different products thus separated are then stored in
sacks, or otherwise disposed of as may be rhost convenient.
The sack-tackle is very simple, and will be readily understood from the drawing. It consists of a
barrel H, provided with a rope of sufficient length to reach to the lower floor of the mill, and fitted to
. On the processes undergone by the corn both previously and subsequently to the grinding. much of the success of the
whole operation depends. In place of the wheat-screen, an apparatus called a sheeling-mill is employed in some establish-
ments. This consists of a pair of ungrooved millstones working at such a distance apart that the grain is merely rubbed
between them, but not cut or broken. From the stones it is received upon an Inclined sleve, where the heavier parts of the
refuse fall from it. and is then exposed to the blast of a fan which deprives it of the remaining lighter portions. For dress-
ing the flour, bolting-machines are very generally used either in combination with, or in place of, the dressing-machines
described above. These contrivances, however, come more within the province of the miller than of the millwright.
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$
9
926.
M.
SCALE.-20 feet=3 inches.
M
K
E
8
131
Literal References.
ions by which the millstone spin-
as bevel wheel and pinion giving mo-
dies are driven.
tion to
A A A, the sheet-iron sides of the
000, the standards or framework of
CC, the vertical shaft of the mill.
house in which the mill is erected.
the grinding machinery.
b, bevel wheel and pinion giving mo-
BB B, the columns for supporting and
PPP, the millstone cases.
tion to
strengthening the sides of the house.
QQ, the large garner for uncleaned
E' E', transverse horizontal shaft.
CC, horizontal beams passing all round
wheat.
cc, a set of small bevel geering giving
the house at the level of the first
R, spout leading from the garner Q to
motion to
floor.
S, the screening-machine.
F F, the longitudinal horizontal shaft.
DD, the roof formed of corrugated
S, the dressing-machine.
d, pulley on the transverse shaft for
iron.
T, a fan attached to the wheat-screen.
driving the screen.
EE, a wall of mason-work affording a
U, a spout leading from the wheat-
c, pulley on the transverse shaft for
foundation for the bearings of the
screen to
driving the dressing-machine.
driving geering, &c.
V W, the first elevator.
f, pulley on the longitudinal shaft for
F, the steam-engine by which the mill
X, passage conducting the grain from
driving the fan.
is driven.
the first elevator to
8, pulley on the longitudinal shaft for
GG. the boilers.
Y YY, the creeper by which it is dis-
driving the elevators and creepers.
H H, the flues and seat of the boilers.
tributed into
h, pulley on the longitudinal shaft for
III, transverse cast-iron beams for fur-
ZZZ, the garners for feeding the
driving the intermediate shaft.
ther strengthening the house.
stones.
i, pulley on the intermediate shaft for
JJ, columns for supporting the beams
A' A' A', the feeding pipes made of tin
driving the sack-tackle.
III.
plate.
G', the intermediate shaft for convey-
KK, the spur fly-wheel of the engine.
B' B' B', the pipes by which the flour
ing motion to
L, pinion working into the above, and
is withdrawn from the stone-cases
H' H', the sack-tackle.
fast upon
into
I', a lever for starting and stopping the
M M, the main horizontal shaft of the
Y' Y'Y', the second creeper-box, con-
sack-tackle.
mill.
ducting it to
K' K', hatchways by which the sacks
NNN, bevel mortise-wheels and pin-
V' W', the second elevator.
are admitted or withdrawn.
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CORN-MILL.
revolve in bearings attached to the roof; it receives motion, when required, from a belt connecting the
pulley on its axis with a shaft G' worked by the engine. The length of this belt is 80 adjusted that the
sack-tackle may remain at rest, or be set in motion, according as the long lever I', (the action of which
is to tighten or relax the belt as may be required,) is drawn to the right or left.
The geering by which the subordinate machinery of the mill is driven consists, first, of an upright
shaft C'C', set in motion by a pair of bevel wheels a, from the main horizontal shaft MM. This shaft
has its lower bearing in an arched standard embracing the shaft M, and at its upper extremity it is
supported by a plummer-block bolted to a double bracket D', imbedded in the wall E. Its motion is
here transferred by means of another pair of bevel wheels b, to the horizontal shaft E', passing trans-
versely across the mill. On this shaft are fixed the pulleys d and e, which drive the screening and dress-
ing machines; and a set of small bevel wheels c c, serve to transmit the motion to the longitudinal
shafts F' F', by which the elevators, creepers, &c., are propelled; as also the short shaft G', by which
the sack-tackle is driven.
The dimensions of the various wheels, pinions, and pulleys, employed in this mill, and the velocities
imparted by them to the machines driven by them respectively, are given in a tabular form below.
Steam-engine F, 12-Horse Power, makes 40 Revolutions of Crank-shaft per Minute.
Driver.
Driven.
Result.
Description of Geering.
Diameter.
Revolu-
Diameter.
Revolutions per Minute.
Feet. In.
tions.
Feet. In.
Spur Pair K L
9
34
40
4
10}
76 on horizontal shaft M.
Bevel Pairs NNN
3
6
76
1
10
140
on the stones.
Bevel Pair a
3
6
76
1
10
140
on upright shaft C'.
Bevel Pair b
3
0
140
1
9
242 on transverse shaft E'.
Bevel Pairs cc
1
1}
242
1 111
140 on longitudinal shafts F' F'.
Pulley d
1
6
242
1
0
363 on screening-machine S'.
Pulley e
1
6
242
1
0
363 on dressing-machine S'.
Pulley f
2
0
140
0
6
560 on fan T.
Pulley g
0
8
140
2
0
46.6 on elevators and creepers.
Pulley h
1
0
140
2
0
70 on intermediate shaft G'.
Pulley i
1
6
70
2
0
47 on sack-tackle H'.
Details of Corn-Mill.-The figures exhibit the constructive details of the grinding apparatus, and
of some of the subordinate machinery employed by Mr. Fairbairn in all his most recently erected
mills, whatever may be their extent and the number of stones they contain. The height of the stone
floor (or level at which the mill-stones are situated) from the foundation varies slightly in different
mills, and the diameter of the driving-shaft must be increased or diminished in proportion to the num-
ber of pairs of stones to be driven, and to the distance of each individual pair from the prime mover.
The only deviations from the form and dimensions here given, are, in the former case, to alter the
length of that part of the framing called the cone B B, and in the latter to increase or diminish the
diameter of the bearings in the plummer-block G G.
Enumeration of the Plates.Fig. 927 is a front elevation of the grinding machinery, exhibiting the
external appearance of the whole.
Fig. 928 is a general section taken on a vertical plane at right angles to that of the elevation, Fig.
929. In this view the millstones and the whole grinding apparatus are shown in combination.
Fig. 929 represents a plan of the cone, showing the number and disposition of the adjusting screws of
the lower stone.
Fig. 930, an enlarged external view of the feeding tube; Fig. 931, an enlarged elevation, and Fig.
932, a plan of the lever for regulating the supply of grain admitted to the stones.
Fig. 933, a plan of the ring forming the top of the tripod on which the feeding hopper is supported.
Fig. 934, a plan of the ring by which the adjusting wedges of the upper bearing of the mill-spindle
are regulated.
Fig. 935, an enlarged view of the mill-spindle.
Fig. 936, an external elevation; Fig. 937, a vertical section; and Fig. 938, a plan of the Ryne, or
crosshead by which the upper stone is connected to the spindle, and the grain supplied to the stones.
Fig. 939 is a face view, and Fig. 940, a plan of the sockets in which the ryne works.
Fig. 941 is a plan of one of the millstones, showing the disposition and mode of drawing the grooves
on its surface.
Fig. 942 is a plan of the cast-iron socket inserted into the lower stone, and forming the upper bearing
of the mill-spindle Fig. 943, an edge view, and Fig. 944, a front view of the brass bushes fitted into
this socket.
Fig. 945, a face view, and Fig. 946, an edge view of one of the wedges by which the brasses of the
mill-spindle are adjusted.
Fig. 947 is a sectional plan of the principal standard or frame of the mill, showing the mode of ad-
justing the lower end of the mill-spindle. The line of section is taken on the dotted line 1-2 in the
general section, Fig. 928.
Fig. 948 is a sectional plan of the standard taken on the line 3-4, Fig. 928, and exhibiting the mech-
anism for disengaging the driving pinion when necessary.
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CORN-MILL.
805
Fig. 949 is a partial section of the standard and attached mechanism. This section is taken on a
plane corresponding with that of Fig. 927.
Fig. 950 is a side elevation, and Fig. 951, a plan of the plummer-block of the driving-shaft.
Fig. 952 is an external elevation, and Fig. 958, a plan of the driving pinion of the mill.
Fig. 954 is a side view, and Fig. 955, a plan of the lever for adjusting the lever of the upper
stone.
Fig. 956 is an edge view ; Fig. 957, a front view of the screw and nut by which the adjusting lever
is regulated.
Fig. 958 is an edge view ; Fig. 959 a plan of the key used for working the above adjusting ap-
paratus.
b
6
E
928.
D
D
D
E
D
927.
0
0
P
0
C
L
B
B
A
I
I
I
N
M
M
F
H
A
SCALE.-16 feet=7 inches.
The figures 960 to 965 represent the different subordinate parts of the mechanism by which the lower
end of the mill-spindle is supported, and its position adjusted.
Figs. 966 to 970. These figures represent the details of the mechanism employed for raising the dri-
ving pinion out of geer with the wheel.
Fig. 971 is an external elevation; Fig. 972, a vertical section; and Fig. 973, a plan, on an enlarged
вся'е, of the small apparatus used for regulating the feeding of the mills.
Figs. 974 to 977. These figures give a representation, on a large scale, of the various adjusting
39
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CORN-MILL.
screws required in this grinding machinery the first two are for adjusting the lower end of the mill-
spindle the third for centering, and the fourth for levelling the lower or fixed stone.
Figs. 978 to 982. These figures represent general and detailed views of a species of small portable
crane or jack, employed for the purpose of raising and replacing the upper millstones when they re-
quire to be redressed.
Fig. 983 is a side elevation, and 984, an edge view of the lower elevator framing.
Figs. 985 to 990. These figures give minute representations of the construction of the creeper.
Figs. 985 and 986 are a section and external view combined to show the mode of junction of the differ-
ent lengths; Fig. 987 is a transverse section of the creeper-box; Fig. 988, a plan of the plug or con-
necting block; Fig. 989, a view of the stud or journal which terminates the range, and Fig. 990, of
that which commences it, and on which the driving-pulley is keyed.
929.
934.
-0
B
D
0
B
935.
931.
J
945.
f
930.
936.
946.
948.
939.
937.
2-91
J
947.
938.
d;
X
940.
939.
General Description. The Framing.-A strong cast-iron standard or framing A A, securely bolted
to a stone foundation by two holding-down bolts, incloses the principal part of the driving and adjusting
geering for each pair of stones. It is made somewhat in the form of an oblong box, and is traversed by
two horizontal diaphragms or partitions, cast of a piece with it, the upper one for sustaining the lower
bearings of the mill-spindle, and the under, the plummer-block of the driving-shaft. It is surmounted
by a large bell-shaped casting BB, called the Cone, firmly bolted, by a flange at its lower end, to the
standard, while the upper extremity is expanded, and terminates in a cylinder, of a diameter somewhat
greater than that of the millstones, the lower of which rests, and is secured, within it. Two straight
and broad flanges are cast at the opposite sides of the cylindrical part, for the purpose of bolting the
cone to the beams of the mill, or to the same parts of the framing of the contiguous pairs of stones,
while another circular flange passes all round, for sustaining the flooring. Three large openings are left
in the upper part of the cone to give access to the interior, and it is provided with suitable arrange-
ments for the reception of the several adjusting screws required for the setting of the lower stone.
The Stone-Case and Feeding Hopper.-Above the cone, and of the same diameter with the cylindrical
part of it, is placed the stone-case C, which surrounds the upper stone, and serves to confine the flour
which is the result of the grinding. This is simply a cylinder of thin sheet-iron, resting upon the stone
floor, and having affixed to the top of it a ring of wood, on which the tripod for supporting the feeding
apparatus is set. This cover is made open in order to admit the air freely between and around the stones
during the process of grinding. A cast-iron ring D, supported by three malleable-iron legs a a a, forms
a sort of tripod in which is placed the hopper E, which receives the grain from the garners above,
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307
through the feeding pipe b, and supplies it to the stones by means of the feeding apparatus to be here-
after described. A piece of coarse wire gauze is placed in the hopper E to intercept any foreign body
that may descend with the grain.
The Driving Geer.-The driving shaft F is part of the line of horizontal shafting which is common
to the whole range, and which receives its motion from the prime mover, generally through the inter-
vention of a single wheel and pinion. The velocity of this line of shafting is usually from 70 to 80
revolutions per minute, with stones of the diameter of those in our examples. The different lengths of
which it is composed are connected together by couplings of the same description as that described and
represented at Figs. 950 and 951. The shaft F revolves in brass bearings, fitted into a plummer-block
G, bolted to a sole formed, as before noticed, in the standard A. The strain of the shaft being en-
tirely in a downward direction, this plummer-block requires no cover, the journal being simply protected
from injury by a slight brass cap.
A large bevel mortise-wheel H, working into the pinion I, on the mill-spindle, serves to transmit the
motion of the shaft F to the latter. The pinion is not fixed immoveably upon the spindle, but is capa-
ble of sliding vertically upon it by means of a sunk feather.
The Mill-Spindle and its Appendages.-The mill-spindle JJ is made of the best forged-iron, accu-
rately turned over its entire length, and rises perpendicularly through the standard A, the cone B, and
the lower millstone. It is attached to the upper, or running stone by means of a cast-iron piece K,
called the Ryne, which combines this function with that of regulating and delivering the supply of grain
to the stones. It is in the form given to this very important part that Mr. Fairbairn's most recent im-
provement in grinding machinery consists. It will be observed by the drawings, Figs. 936 to 940, that
it forms a species of universal joint; the small steel crosshead c c on the top of the mill-spindle
fitting into corresponding bearings in the ryne, while the projecting tails dd, cast upon it at right
angles to the former, work in similar bearings formed of small cast-iron pieces sunk into the stone. By
this arrangement it will be observed, that the connection between the mill-spindle and the upper stone
is complete, while at the same time it admits of the free and unconstrained action of the latter against
the grinding surface of the lower stone.
The lower, or fixed stone is perforated by a large square hole in its centre, into which the cast-iron
block L, Fig. 942, is firmly fixed by slips of wood and wedges. Into this block are fitted the three
brass bushes e e e, which form the upper bearing of the mill-spindle. These are adjusted by means
of the wedges fff, the screwed tails of which pass downwards through the cast-iron ring g, and are
regulated by thumb-screws on each side of it. The large openings in the cone, before alluded to, afford
access for the working of these screws. Small semicircular chambers are formed in the socket L, be-
tween each bush, and filled with hemp and tallow, for the lubrication of the mill-spindle; and the whole
is carefully protected from dust by slips of sheet-iron screwed over it, Fig. 941.
941.
a
933.
943.
L
L
J
942.
944.
The Millstoner-The diameter of the millstones most in use at the present day is 4 feet, and their
thickness about 12 inches one-half of this thickness is composed of French burr, a very hard, though
porous mineral, of a silicious nature: the other half is made up of plaster of Paris. In consequence
of the difficulty of obtaining sufficiently large masses of the French stone, it is usual to construct the
millstones in segments, which are cemented together, and the whole firmly bound by iron hoops passing
round the circumference. The lower stone is, in the first instance, carefully dressed into a perfectly flat,
plane surface, but the upper one is made slightly hollow for a small distance from the central aperture,
80 as to allow the grain to be freely admitted between the stones. Being thus prepared, grooves are
then cut on the rubbing surfaces of both, in the manner indicated in Fig. 941. The circumference of the
stone is first divided into eleven equal parts; lines are drawn from each division to the centre these
radii determine the limits of the grooves in each compartment. A chord b' c' is then drawn, joining the
bounding radii of any two compartments; this chord is, of course, bisected by the intermediate radius
J a', in d'. Divide the line d' c' into four equal parts in the points e' f' g' and from these points mark
off, on the line d' c', distances equal to the width of the groove to be cut; then draw through all these
. The number of channels formed in the stones, and consequently the number of compartments, or quarters into which
they are primarily divided, are varied by different millers, but the mode of drawing the lines, as here given, is applicable
in all cases.
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CORN-MILL.
Literal References.
A A, the standard or lower framing
of the grinding machinery.
B B, the cone or upper framing.
C, the stone-case, of sheet-iron.
D, a cast-iron ring forming the sup-
949.
port of the feeding hopper, and carried
upon
aaa, three malleable-iron legs, rest-
ing upon the top of the stone-case.
E, the feeding hopper.
b, a pipe made of thin sheet-iron,
supplying grain to the feeding hop-
per from the garners above.
F, the main driving-shaft.
G, the plummer-block in which the
shaft F revolves.
H, the bevel mortise-wheel, com-
municating the motion of the shaft
F, to
m
I, the pinion of the mill-spindle.
J, the mill-spindle.
K, the ryne of cast-iron, by which
m
the mill-spindle is connected with the
upper stone, and the feeding is regu-
lated.
cd, the bearings of the universal joint
formed by the ryne.
H
H
L, the cast-iron socket for the upper
bearings of the mill-spindle.
e f, bushes and wedges for adjusting
#
the upper bearing of the mill-spindle.
J
8, a thin cast-iron plate, by means of
960.
which the wedges ff are tightened and
950.
951.
retained in their places.
hhh, pinching-screws for adjusting
o
a
the level of, and
961.
iiii, pinching-screws for centering
R
the lower mill-stone.
i, a large brass nut, with jam-nut, for
retaining the pinion I constantly in its
962.
proper position with regard to the driv-
ing wheel.
k, the footstep of the mill-spindle, of
963.
brass or gun-metal.
21
952.
1, cast-iron socket for the footstep k.
959.
958.
953.
M m, pinching-screws for adjusting
the socket 1.
m, the saddle or link connecting the
footstep k with
M, the great lever for supporting and
regulating the position of the mill-
spindle.
971.
N, the screwed rod for working the
lever M.
964.
965.
e, cast-iron screw-key for the same.
o, the moveable feeding-pipe of
973.
cast-iron.
P, lever for regulating the position of
the feeding-pipe O.
p, small column forming the centre
972.
of motion of the lever P.
975.
Q 9, apparatus for working the feed-
ing mechanism.
R, a cast-iron ring for raising the
974.
driving pinion out of geer with the
o
956.
wheel.
S, a cast-iron crosshoad, being part
of the same apparatus.
957.
rr, upright rods connecting the cross-
head S, with the ring R.
ss, a hand-wheel for working the
disengaging geer.
?
4 a screw working through the eye
977.
976.
of the hand-wheel 8.
T U V W, the several parts of which
the stone lifting machine is composed.
ur, the centres of motion on which
it rotates.
X, the lower elevator-frame, of cast-
iron.
Y Y, the creeper, of cast-iron.
to =, blocks and stude for connecting
the adjacent lengths of the creeper.
1/2 the brackets in which it revolves.
Z, the creeper-box, of wood.
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CORN-MILL.
309
points of division lines parallel to the radius J a', terminating them in the radius J c'. These are the
outlines of the grooves, which are then to be cut into the stone, perpendicularly on one side and ob-
liquely on the other, so that each furrow shall have a sharp edge. The direction of the grooves being
the same in both upper and lower stones as they lie on their backs in the position proper for being cut,
RD
a
978.
981.
o
W
o
o
V
982.
W
T
979.
b
U
T
T
U
980.
U
E
954.
M
o
M
955.
M
984.
983.
X
X
X
it is obvious that when the former is reversed and set in motion, their sharp edges will meet each other
after the manner of a pair of scissors, (as partially shown by the dotted lines in Fig. 941,) and thus
grind the corn more effectually when it is subjected to the action of the unbroken surfaces between the
channels.
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CORN-MILL.
Adjustment of Lower Stone.-It is of the most essential importance to the proper working of any
pair of stones, that the grinding surface of the lower stone should be perfectly level, and that its centre
should be exactly perpendicular above that of the lower bearing of the mill-spindle. To secure the
former of these conditions, three pinching-screws h h h, are fitted into the cone, (that number being
greatly preferable to four in adjusting the level of any surface;) and, bearing against small slips of
iron sunk into the stone, it can be raised or depressed by them to any required extent. The centering
of the stone is effected by means of four pinching-screws i i ii, acting horizontally upon it. To secure
it against deviating from the truth after having been properly adjusted, all these screws are provided
with jam-nuts.
Adjustment of Mill-Spindle.-The lower bearing or footstep of the spindle J is also made capable
of nice adjustment, both horizontally and vertically. The former is necessary in order to ensure the
accurate working of the driving wheel and pinion, and the latter to regulate the pressure of the upper
upon the lower stone, and to compensate for the changes produced upon both by the frequent dressings
which their grinding surfaces have to undergo.
970.
969.
966.
968.
R
R
R
966.
985.
987.
23
989.
988.
990.
The footstep k, which is of gun-metal, is turned and fitted accurately into a cast-iron socket l, resting
on the upper diaphragm of the standard A; the hole into which it is inserted and the annular recess by
which it is surrounded being made of somewhat greater diameter than the corresponding parts of the
socket itself. Its exact position is determined and secured by the four lateral pinching-screws m m,
passing through the ring and working in nuts fitted into recesses cast upon its interior surface. (See
Figs. 947 and 975.) The footstep k is not fixed immoveably into the socket l, but is capable of sliding
vertically in it. Its proper position, in this direction, is regulated by means of a strong malleable-iron
lever M, having its centre of motion in the back of the standard A, while its opposite end projects
through a slot, and is raised or depressed by means of a screwed rod N, joined to it and passing through
a projecting shelf cast upon the front of the standard. A small link or saddle n, serves to connect the
lever with the footstep k; the saddle being provided with a square tail which is inserted into a similar
recess in the under side of the footstep; by which means the latter is prevented from turning in its
socket. Thus it will be seen that the entire weight of the upper stone and mill-spindle rests upon the
lever M, and that the miller is enabled to vary at pleasure the pressure upon the grain between the
stones, and consequently, the degree of fineness of the flour produced, by simply turning the nut of the
screw N by means of the key O.
The Feeding Apparatus.-The supply of grain admitted between the stones is regulated by means of
a cast-iron pipe O, open at both ends, the lower end being brought into close proximity with the ryne,
while the upper part incloses the pipe in which the feeding hopper E terminates. It is suspended by
means of a cast-iron lever P, which has its fulcrum in the small column p, depending from the tripod D.
A small chain attached to the end of the lever, and passing over a friction-pulley at the bottom of the
stone-case, serves to connect this feeding apparatus with an ingenious little piece of mechanism Q attached
to the standard, by which the miller is enabled to regulate the supply with the greatest nicety.
This contrivance (which is represented on a large scale at Fig. 971) consists of a small hand-wheel q,
working between the cheeks of a double bracket bolted to the standard A. A small screwed pin forms
the axis of this wheel; it passes freely through the cheeks of the bracket, but is screwed into the eye
of the hand-wheel, and is prevented from turning with it by means of a feather inserted into the former
and fitting into a groove cut throughout the entire length of the pin, to the upper end of which the chain
is attached. By this arrangement it is obvious that by turning the hand-wheel q to the right or left
the small pin will be raised or depressed, and, through the intervening mechanism, the size of the open-
ing between the mouth of the feeding-pipe o and the ryne will be increased or diminished.
The form given to the upper surface of the ryne may be looked upon as the highest point of perfection
to which this important part of grinding machinery can be carried. We have been at great pains to give
an accurate representation of it in our various views, (see Figs. 928, 936, 987, 938, 939, and 940.)
The principle by which its form is determined is, that the centrifugal force of the running stone shall
be employed in the most effectual manner to distribute the corn equally over every point of its surface,
while at the same time, the supply admitted shall be susceptible of the nicest possible adjustment.
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The Disengaging Apparatus.-The driving pinion I is fitted upon the mill-spindle 80 as to be capable
of sliding up and down upon a sunk feather. When fully in geer with the wheel H, it rests upon a collar
formed on the upper surface of a large brass nut j, by which the miller is enabled to keep the pinion
invariably in its proper position with regard to the wheel, independently of the position of the spindle,
which, as we have before had occasion to remark, requires to be slightly lowered every time the stones
are dressed. When properly adjusted, the pinion is secured to the spindle by a tapered key.
It is, however, necessary to throw each pair of stones, periodically, out of geer with the general range,
to admit of their being dressed, dc. For this purpose the tapered key is removed and the pinion raised
out of contact with the teeth of its driving-wheel by means of a species of small jack or lifting apparatus
attached to the standard, the component parts of which we shall now briefly enumerate. A cast-iron
ring R, supported upon two upright rods r r, is brought into contact with the under surface of the pinion
by turning the hand-wheel 8, which is screwed upon its axis t, and carries with it in its ascent, the cross-
head S, into the ends of which the lower extremities of the rods r r are inserted. The screw t is fixed
into a socket cast upon the under surface of the lower diaphragm of the standard, and the connecting
rods r r pass through holes formed for their reception in both diaphragms; being set in a diagonal direc-
tion in order to clear the lever M, and other important parts of the machinery.
On turning the hand-wheel in the contrary direction, the weight of the pinion again brings it into its
working position.
The Stone-lifting Machine.-Fig. 978 is a representation of a portable lifting apparatus, for raising
the upper stones from their beds and depositing them on the floor of the mill, when they require to
undergo the process of dressing. It consists of a strong malleable-iron arm TT, bent into a form nearly
approaching to a quadrant; the lower end works in a cast-iron step v, inserted into the stone floor, while
its upper extremity is supported by a strong rod U, fitted to rotate upon a stud 26, fixed into a cast-
iron plate (Fig. 981) bolted to the beams which support the floor above. The fixed centres 26 and v
are so situated that the machine shall command two contiguous pairs of stones, and the end of the
rod U is made of such a form as to admit of its being easily disengaged from the stud; when the
entire machine may be removed. A strong screw V, passing through the arm T, and worked by means
of a nut formed into a double handle, carries at its lower end the two connecting links W W, which are
attached to the stone by two studs temporarily inserted into it at points diametrically opposite. The
links W W are bent so as to admit of the stone being inverted while it is suspended in the lifting
machine. The running stone is retained in its place in the mill simply by its own weight; it is,
therefore, only necessary to raise it out of its bearings when the grinding surfaces require examination
or repair.
The Elevators and Creepers.-Figs. 983 and 984 are a representation of the form given to the
lower elevator-frame; the nature and construction of this machine having been fully noticed in our
previous description, it is not necessary further to advert to them. The creeper, however, Fig. 985, is
an object of greater interest. The material employed is cast-iron; the creeper is made in six feet lengths;
each length being in the form of a tube, 31 inches in diameter, and about 1 of an inch thick, with broad
leaves or threads cast round it in the form of an Archimedean screw. The thickness of the threads does
not exceed 3 of an inch at the outer extremity.
The different lengths of which the entire creeper is composed, are joined together by short malleable
iron studs x x, forming also the journals on which it revolves. These are made with square tails fitted
into similar holes formed in the centre of the small cylindrical blocks w w, which are carefully turned
on their exterior surfaces, and driven into the open ends of the pipes Y Y, previously bored to the
same diameter. This construction at once insures a strictly rectilinear axis for the entire range, what-
ever may be its length. Minor details will be understood by a simple reference to the figures. The
arrow indicates the direction in which a creeper, constructed in the manner shown in the general view,
would propel the grain.
CORN-MILLS of MM. Cartier and Armengaud, Sen. The corn-mills after the American system,
have undergone useful and important alterations since their introduction into France, though but
recently introduced. This system was followed but slowly from the difference in its operation from
that of the French mills. The owners of the old mills were satisfied with the work done, with little
care on their part respecting improvements.
It is only since the importation of the American process that this industry has received a new impulse,
and that a new era has commenced; for this system has driven before it the routine with which the old
system was encumbered. The new system was already well known all over England when it made its
appearance in France, where it received great amelioration.
The old method required a large number of hands, while the new supplies their place, or rather their
work, by the ingenious motions imparted to the different parts of the mills by the machinery.
The construction of the different pieces, as well as their disposition, are not always similar; the mill
of Cartier and Armengaud appears to us the most worthy of notice; there are ten couples of millstones
set in motion by the same hydraulic wheel.
Explanation of the Figures.
Fig. 991, front exterior view of the mechanism of the mill, (first system.)
Fig. 992, a vertical section of the axis on the line 1-2, of the plan, Fig. 997, (second system.)
Fig. 993, a vertical section, perpendicular to the preceding, on the line 3-4, Fig. 996.
Fig. 994, a section through the axis of a stone and of a pillar, on the line 5-6, Fig. 995.
Fig. 995, a horizontal section above the platform, parallel to the line 7-8, of the preceding Fig.
Fig. 996, the general plan of the first system, showing the disposition of the millstones. This plan
exhibits the work at different heights, in order to bring under observation the covers of the stones, the
inferior stones and their flooring, the triangles and frames which contain them.
Fig. 997, the general plan of the second system, with disposition altogether similar to the first. The
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CORN-MILLS.
horizontal sections are here represented at different depths underneath the frame-work of the stones,
exhibiting the pinions of the stones and the horizontal wheel commanding them, the pedestals into
which are inserted the ends of the axles of the stones, the pillars and circular platform which gives
support to the whole.
H
A
U
U
R
992.
a
SCALE.-66 feet=13 inchea.
B
at
A
4
991.
S
T
0
Figs. 998 and 999, a vertical section and plan of the iron axle of a mill-stone.
Figs. 1000 and 1001, a vertical section and plan of the superior portion of one of the cast-iron pedes-
tals.
Fig. 1002, a steel socket on which the iron axle of the mill turns.
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313
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References to Figs. from 991 to 1002.
A, circular stone-work, on which the whole system, com-
m, cast-iron fulcrum, having brass pillows, on which the
posed of six couple of stones rest.
turning pieces of the two shafts N rest; their plates
B, the circular platform of cast-iron placed on the stone
are set in a groove made in the stones supporting them.
frame-work.
o, bevel with wooden coga, and fitted to the shafts N.
C, six iron pillars of equal height, fixed to the platform by
P, cast-iron pinions.
pins which penetrate them their whole length, and also
Q, vertical shafts in cast-iron, turned their whole length,
the stone circle.
bearing the pinions P.
D, the cast-iron rim, made of one solid piece; the pine of
Q, iron shaft, fitted to the summit of the preceding axles,
the pillars also penetrate it, thus fixing them firmly to
and going towards the upper stories to work the clean-
this rim.
ing bolting apparatus.
a, six long pins traversing the rim, the pillars, the platform,
R, a horizontal wheel, with six arms, ending in ears pinned
and all the thickness of the stone-work, thus firmly bind-
to the boxes of the millstones; its centre has three brass
ing the different parts to each other.
flat pillows, which keep the axle in a vertical position
E, six cast-iron cases resting on the cornice, in which the
force-screws press them at will.
lower millstone is contained.
o, keys, which maintain the pinions and the wheels S at the
F, cast-iron triangles, placed at the bottom of the cases, in
height determined for them, to prevent their fall, in case
order to give the position required to the under mill-
the screws which keep them fixed to their axle should
stones.
become loose.
b, screws adapted to the triangles, to govern them.
p, steel extremity of every vertical shaft to which it is
a iron plate fixed to the rim, into which the resting-rods L
adapted, having a conical shape; the contact suffices
are screwed, receiving the pressure exercised by the nuts
to keep them connected.
of the pine a.
R', great chair in cast-iron; the basis of which is solidly
& Fig. 996, square-headed screws binding the cases to the
pinned to the stone R2.
rim.
R2, a large stone placed at the centre of the works, so die-
a round-headed screws holding the immoveable stones.
posed as to bear both systems.
F, immoveable stones, of the diameter of 4-26 feet, iron-
q, rest-rod of the vertical axle; it is made of iron, flanged
bound, and borne upon the triangles F; they are fur-
at its inferior portion, which goes through a nut in
rowed, as indicated in Fig. 996.
iron T.
Fa, running wheel, of the same diameter, revolving above
r, nut, in iron, with square fianges, placed upon the centre
the former. They are also 4.26 feet diameter.
of the base of R'.
G, vertical axles in cast-iron of the running wheels moving
r, brass socket, adapted to a cast-iron muff, and containing
them.
a steel bed, similar to that of the milistone axles: it re-
f, cast-iron bushing of a conical shape, adapted to the
ceives the point of the vertical shaft, and is governed by
axle G.
four screws.
8, cast-iron chuck, having two arms contained within f,
8, a horizontal wheel, having fine wooden teeth, and fitted
attached by their extremities to the moveable stone, and
to the vertical shafts.
held in equilibrio upon steel disks, adapted to the axle of
T, straight pinions, made of cast-iron, adapted to the axles
the stones, and having a spherical part, which serves as
of the stones, and to which the rotatory motion is given
a pivot to the centre of the chuck.
by the horizontal wheel S.
H, cast-iron cylinder fixed to the nether millstones, Figs.
U, wooden box surrounding the millstones it is placed
997 and 998.
upon the flooring of the first story.
4, flat pillow in bronze, contained within H, and bearing
V, brass hopper, distributing the grain to the stones.
against the iron axles of the millstones.
s, zinc pipe, communicating with the hopper, which is
N, braces; they are of cast-iron, placed in the bottom of
placed in the second story. Valves open and close it.
the drums, and fixed to them; they serve to keep the
4 brass tube, fitted into the lower part of the hoppers, and
pillows firmly fixed.
descending as far as a.
42, cast-iron wedges, pressing the pillows against each other.
t, small tube, enclosed within the last, when its opening is
i, steel pins, adapted to the inferior portion of the iron
to be leasened before grinding the corn.
axles connected with the stones.
& cross iron bar, the extremities of which are supported
a Fig. 1002, steel socket, in which the ends of the axle 8"
by screws; their office is to keep the tubes & at the
rest.
desired height.
I, vertical rods of iron, by which the axles and consequently
v, small cast-iron supports, attached to the lids of the mill-
the millstones are raised.
stone box.
J, cast-iron pedestals, mostly round, and pinned by their
X, a great circular shoot, in wood or sheet-iron, in which
base to the circular platform.
the ground corn is received at its exit from the stones;
is cast-iron sockets, placed in the superior part of the pedes-
it rests upon the wheel R.
tals; their shape is seen in Fig. 1000.
Y, spur-wheel, of cast-iron ; it turns upon the vertical shaft,
j, brass socket made to be adapted to the cups j; they
and gives attachment to the moveable branches of the
rest upon the summit of the vertical rods I, to rise and
shoot.
descend with them, and receive the sockets 13.
I, six iron branches, attached with pins to the ears of the
f, a screw to set the sockets in the centre, and consequently
wheel Y, which rotates them very slowly.
the axles of the millstones.
x, wooden plates, fixed to the extremities of the branches I
K, cast-iron balance-beam, connected with the resting-rods.
they turn with them within the shoot, carrying forward
4, iron bolts, serving to rest one end of the beam K a nut
the meal to the box of the endless screw.
maintains each of the bolts fixed to the platform.
y, pinion, commanding the wheel Y.
L, long rod, connected to the beam K, but allowed to re-
y, strait wheel, cast with the preceding pinion, and fixed
volve round its own axis.
with it to an iron gudgeon, adapted to one of the arms
4 a portion of L, of a greater diameter than the rest, and
of R.
tapped at the height of the rim.
re, a similar wheel on the vertical shaft, and transmitting its
r, cast-iron fly-wheel, at the summit of each rod L, in order
movement to y.
to turn them by the hand.
Z, an endless screw, made of wood, having an iron axis
M. large cast-iron cog-wheels, communicating with the
and a wooden screw it is inclosed within a rectangular
moving wheel M', and transmitting their movement to
box of wood, into which the meal from the shoot is re-
the two systems.
ceived.
M', vertical moving wheel in cast-iron, in two pieces, and
z', an oaken box, in which the ground grain falls.
adapted to the axle of a hydraulic wheel.
4 a double pulley, mounted upon the extremity of the end-
m, cast-iron bushing round each axle of the pinions; they
less screw, and free on this axle.
can slide on It laterally.
z', an endless chain, with tin buckets, fixed at intervals, in
m', screw, by which the bushing is made to engage with its
order to raise the meal from the box Z to the room
pinion; it is disengaged at will, when it is to put in or
where it is allowed to cool.
out of geer.
22, a small pulley, commanding the endless screw.
N, two cast-iron shafts, bearing the pinions M, and the bevel
wheels O.
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CORN-MILL.
CORN ELEVATOR, Steam: Pagin's Patent. In the new warehouses attached to the Atlantic
Docks, Brooklyn, there are several of these very useful engines erected. Also one on the river for dis-
charging grain-laden ships in the stream or alongside the piers: the latter is called the floating eleva-
tor. The extremity of the shoot C is inserted in the hold of the vessel about to be discharged, its height
being regulated by the guide-frame and pulleys, Fig. 1003. The machine is put in motion by means of
the prime mover A and band-wheel B, when by means of a series of tin dippers attached to a belt of
gutta percha or leather, tightly stretched over the wheels at B and C, the corn is brought up to a height
1003.
of 76 feet, and discharged by means of the small spout attached to the elevator into the weighing ma-
chine; from thence, by a repetition of the same contrivance, it is taken through the building to a shoot
on the roof, containing an Archimedean screw, by the use of which and the elevator the grain may not
only be placed on any particular floor in the warehouse, but may be transhipped (having been weighed
in its passage) either wholly or partially for Europe, or any other destination.
This apparatus was erected by Barton, of Buffalo, and by means of a small high-pressure engine,
10-horse power, will raise 2600 bushels of grain 76 feet high per hour, and distribute or tranship as
described.
CORN-MILL, Old Union. In order to render our series of Corn-Mill drawings complete, we have
given in Fig. 1004 a representation of the arrangement of the stones, garners, &c., in an extensive estab-
lishment fitted by Mr. Fairbairn with machinery identical, in all important particulars, with that which
we have detailed in the preceding figures and descriptions.
This mill contains seventeen pairs of stones. The whole are disposed in one straight line, close
to the wall of the mill-which arrangement, on account of its undoubted superiority to any other, has
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CORN-MILL.
317
induced us to select this example. The flour produced is, for the most part, consumed by an extensive
baking establishment adjoining the premises, and belonging to the same proprietors.
For our present purposes, we have deemed it necessary to give only a sectional elevation, on a small
scale, and of a somewhat sketchy nature. The line of section must not be supposed to be taken in one
vertical plane, but to vary in order to exhibit most distinctly the different parts.
Description-Two powerful steam-engines are employed to drive the machinery of this mill; one of
these communicates its motion to the line of horizontal shafting, near the end of the range, by means of
a great bevel-wheel A, keyed to the crank-shaft, and working into the bevel mortise-pinion B upon the
mill-shaft; the other, by means of a spur fly-wheel working into the mortise-pinion C, situated towards
the centre of the range. By thus applying the power at two points, the weight of shafting and conse-
quent loss from friction, &cm is materially diminished.
From the driving-shaft DDD, the power is communicated by the bevel pairs a a a, to the mill-spin-
dles, which are provided with suitable bearings and adjusting geer, in all respects identical with that
we have already described. Between the first and second pairs of stones, one of the standards E is
employed for the purpose at once of giving great stability and firmness to the shaft D at the point
where it receives the strain of the first engine, and of affording the means of transmitting its motion to
the upright shaft driving the lighter machinery of the mill. A strong cast-iron bracket b, bolted through
the wall of the mill, abuts against the framing, and the intermediate stays c c bind all three together
laterally.
Each of the feeding hoppers ddd is supported by a light cast-iron framing e, resting upon slender
columns; the tripodal form is, however, preferable to this.
The feeding-pipes HHH are of tinned plate, 80 constructed as to be easily withdrawn from their con-
nection with the wheat-garners when the stones are taken up; and at the top of each is a small valve or
slide h, to shut off the supply of wheat. Above these points the passage of the grain from the cleaned
wheat-garners is effected by means of wooden spouts III, converging to and communicating with them.
The cleaned wheat-garners J JJ are three in number, and are situated on the top floor of the mill,
immediately over the stones. Between, and in front of these, are the garners K K, which receive the
wheat as it is first brought to the mill, and deliver it, by means of numerous spouts or openings in the
floor, to the great uncleaned wheat-garners LL, situated on the machine flat. From these the un-
dressed wheat is conveyed, by means of a creeper and elevator, into the screen M, whence it falls
through the spout P into an elevator on the stone floor, by which it is again raised to the upper story
and distributed, by another creeper, into the cleaned wheat-garners J JJ.
The vertical shaft ii is continued upwards till it terminates near the roof of the machine floor. Then
its motion is transferred by means of a short transverse shaft, (which we have purposely omitted in our
drawing for the sake of simplicity,) and two pairs of bevel wheels, to the long horizontal range of shaft-
ing k k, on which are fixed numerous pulleys for driving the various subordinate machinery of the mill.
The pulley l drives the lower creeper.
The pulley p drives the second elevator.
"
"
m
"
the upper creeper.
"
"
"
q
the fan (belt working over
"
"
n
"
the sack-tackle.
guide pulleys.)
"
"
"
o
the first elevator.
"
"
"
r
the wheat-screen.
The dressing and bolting machines are driven by pulleys on the transverse shaft. The apparatus Q
for raising the stones is shown here in action; it may be remarked that it is found necessary, in this
mill, to keep a couple of stone-dressers in constant employment; each pair of stones being, in success-
sion, thrown out of geer for twenty-four hours, to undergo the process of redressing.
Calculation of Velocities.
1st Steam-engine makes 48 Revolutions of Crank-shaft per Minute.
9d
do.
22
do.
do.
do.
DRIVER.
DRIVEN.
RESULT.
Description of geering.
Revolu-
Revolutions per Minute.
Diameter.
Diameter.
tions.
Ft.
In.
Ft.
In.
Bevel pair A B
6
81
48
4
6
18 21
22
5 7
}
71.57 on horizontal shaft D.
Spur fly-wheel into C
Bevel pairs a a a
8 6
71.57
1 10,1
132 on the millstones and upright i.
1st pair of small bevels
3 0
132
2 11
184 on the transverse shaft.
2d
do.
do
1 6
184
1
10
149 on the longitudinal shaft k.
Diameter of the millstones, 4 feet.
Literal References to Fig. 1004.
A, the great bevel-wheel on the crank-shaft of first engine.
B, the pinion on the mill-shaft working into the above.
C, a spur cog-pinion on the mill-shaft driven by the spur fly-wheel of the second engine.
DDD, the range of mill shafting.
EEE, the standards or lower framing of the mills.
FFF, the cones or upper framing of the mill.
GGG, the stone-cases.
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318
CORN-MILL.
A
-
B
H
E
J
K
H
H
g
-
a
i
26
1004.
a
C
J
+
SCALE.-11 feet==1 inch.
L
K
L
H
d
G
E
D
J
T
il
M
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COAL, ANTHRACITE.
319
aaa, the bevel wheels and pinions for driving the mill-spindles.
b, a strong bracket for strengthening the bearing of the pinion B.
c c, two cast-iron cross-stays for the same purpose.
ddd, the feeding hoppers.
ece, the frames supporting the feeding hoppers.
fff, the cast-iron moveable feeding-pipes.
ggg, the small screw and hand-wheel for working the feeding apparatus.
HHH, sheet-iron feeding-pipes from the machine floor to the hoppers.
hhh, slides for shutting off the supply of wheat when necessary.
III, wooden spouts or square pipes for leading the grain to the feeding-pipes HHH from
JJJ, the cleaned wheat-garners on the top floor of the mill.
KK, the first uncleaned wheat-garners emptying their contents into
LLL, the great uncleaned wheat-garners on the machine floor.
M, the brusher or wheat-screen.
N, the fan attached to the wheat-screen.
0, passage of the blast, carrying the dust, &c., outside of the mill.
P, passage of the cleaned wheat to the second elevator.
ii, the upright shaft for driving the light machinery of the mill.
j, a pair of bevels between the upright shaft and
k, the range of longitudinal shafting down the mill.
lmnopqrs, pulleys for driving the various light machinery.
Q, the stone-lifting machine shown in operation.
ttt, studs affixed to the beams supporting the machine floor, affording fixed centres for the working
of the lifting machine Q.
COAL, ANTHRACITE It is useful to state that the anthracite coal is broken and screened into
three different sizes; viz. egg size, nut size, and pea size.
The dust and pea-coal mixed, that is to say, the screenings from nut-coal, are most commonly in use
for small stationary engines. It costs about one-half the price only of the larger coal and, with proper
care, can be made to generate almost as much steam.
The grate bars are thin and deep: the depth is generally nearly 5 inches in the centre for bars 4 feet
long. By these means a large surface is provided for the radiation of heat from the bars to the cur-
rent of air passing between them; and thus, the space between the bars being necessarily small, a suf-
ficient supply of air is admitted into the furnace.
The fire is usually ignited with a little pine wood kept for that purpose. The fan or blower is.set to
work, and the fire is then fed by the shovel in the ordinary way.
Care must be taken that too much coal be not put on at one time, nor any faster than it is consumed.
It must be equally distributed over the surface; by these means the stoker is enabled to get a body of
fuel on the grate of about 6 inches thick, the fire being all the time brisk and equal, and the combus-
tion perfect; but, if these rules are neglected, the grate becomes clogged, and the necessary current of
air is excluded. It is a common phrase among the firemen that they must keep the surface of the fire
always dancing. The rapid supply of oxygen from the fan is essentially necessary for the proper com-
bustion of the small coal; but by its agency the mere sweepings, the refuse coal, answer all the pur-
poses of large coal, at half the cost; and it is quite extraordinary how small an amount of combustible
matter is permitted to escape.
Analysis of Coals.-Pennsylvania. Coal from Nesquehoning mines, from the tenth feet veins, east
drift, Northampton county. Structure irregularly columnar; fracture irregularly conchoidal; color
grayish black; lustre splendent.-Volatile matter, 6.40; Carbon, 86.60; Ashes, white, 7.00: Total, 100.
Coal from Summit mines of the Lehigh Company, from a vein said to be 14 feet thick, Northampton
county. Structure massive, compact; color black; metallic lustre brilliant.-Volatile matter, 7.50;
Carbon, 88.50; Ashes, dull white, 4.00.
Coal from Summit mines, Lehigh Company, Northampton county, hardest variety. Structure dense,
laminated; fracture smooth, somewhat conchoidal; color metallic, black; lustre splendent.-Volatile
matter, 6.60; Carbon, 87.70; Ashes, white, 5.70.
Coal from Tamaqua mines, on east side of the river, called vein D, east, Schuylkill county. Texture
nearly compact, somewhat slaty; fracture conchoidal; grayish or iron black; lustre splendent; specific
gravity 1.57.-Volatile matter, 5.03; Carbon, 92.07 Ashes, white, 2.90.
Coal from Tamaqua mines, vein E, east, Schuylkill county. Texture compact; fracture conchoidal;
grayish black; lustre splendent; specific gravity 1.60.-Volatile matter, 4.54; Carbon, 89.20; Ashes,
very white, 6.26.
Coal from Tamaqua mines, R vein, in the Sharp Mountain. Texture compact; tendency to lamina-
tion; grayish black; lustre metallic, splendent. Specific gravity, 1.55.-Volatile matter, 7.55; Carbon,
87.45; Ashes, white, 5.10.
Coal from Fuscurora mines, from second drift, south of Jackson's mine, Schuylkill county. Structure
slightly laminated, tolerably compact; irregular conchoidal fracture; color black; lustre splendent.-
Volatile matter, 7.50; Carbon, 88.20; Ashes, pink brown, 4.30.
Coal from the Schenoweth vein, Pottsville, Schuylkill county. Structure compact; irregular fracture;
color black; lustre splendent; specific gravity, 1.50.-Volatile matter, 1.40; Carbon, 94.10; Ashes,
light brown, 4.50.
Coal from Neeley's tunnel, third vein, Schuylkill county. Texture compact; iron black; fracture
conchoidal lustre splendent specific gravity, 1.55.-Volatile matter, 5.40; Carbon, 89.20; Ashes, light
yellow, 5.40.
Coal from Sharp Mountain, Pine Grove. Texture laminated; gray black; fracture splintery lustre
splendent; specific gravity 1.54-Volatile matter, 7.15; Carbon, 80.57 Ashes, 8.28.
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COAL. ANTHRACITE.
Coal from Black Spring Gap, Dauphin county, twenty-five miles east of the river. Massive, friable;
fracture irregular; color iron black; lustre somewhat splendent; specific gravity, 1.44.-Volatile mat-
ter, 9.53; Carbon, 82.47 Ashes, yellow white, 8.00.
Coal from Lea vein, 7 feet thick, near Black Spring Gap, Dauphin county. Structure laminated;
brittle, black, shining; specific gravity, 1.35.-Volatile matter, 8.96; Carbon, 85.84; Ashes, cream
color, 5.20.
Coal from Grey vein, 16.7 feet thick, near Black Spring Gap. Massive; fracture irregular; color
black considerable lustre; specific gravity, 1.44.-Volatile matter, 9.78; Carbon, 81.02; Ashes, light
orange, 9.20.
Coal from Grey vein, near Black Spring Gap; included gray band. Structure somewhat fibrous;
brittle; color gray-black, smutty dull metallic lustre; specific gravity, 1.33.-Volatile matter, 11.40;
Carbon, 81.40; Ashes, pale ochreous, 7.20.
Coal from Peacock vein, Gold Mine Gap, Dauphin Co., 25 miles east of the river. Structure massive,
with a tendency to columnar fracture angular; color black; shining, irised specific gravity, 1.41.-
Volatile matter, 10.95 Carbon, 82.15; Ashes, light orange, 6.90.
Coal from the Heister vein, Gold Mine Gap, Dauphin Co. Structure massive; strive distinct; color
jet black; lustre shining; specific gravity, 1.41.-Volatile matter, 10.43; Carbon, 81.47 Ashes, pale
yellow, 8.10.
Coal from vein supposed to be the Peacock vein, west side of Raush Gap, Dauphin Co., twenty-one
miles east of the river. Structure massive; friable; small columnar; fracture irregular; color black
iridescent; specific gravity, 1.45.-Volatile matter, 10.57 Carbon, 77.23; Ashes, pale orange, 12.30.
Coal from Yellow Spring Gap, Dauphin Co., sixteen miles east of the Susquehanna. Structure slaty,
somewhat brittle; fracture irregular; black; lustre shining specific gravity, 1.41.-Volatile matter,
10.95 Carbon, 79.55; Ashes, pale yellow, 9.50.
Coal from Ruttling vein, Dauphin Co., thirteen miles east of the river. Massive, regular fracture,
tendency to lamination; cross fracture shining black between the laminæ lustre feeble; coke light and
spongy.-Volatile matter, 13.75; Carbon, 74.55; Ashes, 11.70.
Coal from big flats, Dauphin Co., nine miles east of the river from the shaft. Massive; irregularly
laminated; fracture irregular; striæ small and distinct jet black; and considerable lustre; makes good
coke.-Volatile matter, 15.06; Carbon, 76.94; Ashes, orange, 8.00.
Coal from Lyken's Valley, third bed, Dauphin county. Texture laminated, brittle; fracture fibrous;
color jet black, shining.-Volatile matter, 8.85; Carbon, 88.25; Ashes, 2.90.
Coal from Shamohin coal mines, Snyder's mine. Structure massive, compact; fracture laminated
beautifully iridescent.-Volatile matter, 6.10; Carbon, 89.90; Ashes, 4.00.
Coal from Wilkesbarre, Luzerne county, Warden's vein. Texture compact; iron black; lustre splen
dent; fracture conchoidal; specific gravity, 1.403.-Volatile matter, 7.68; Carbon, 88.90; Ashes, 3.49.
Coal from Wilkesbarre coal basin, Carbondale mines, Luzerne county. Texture laminated, laminse
compact; iron black; fracture somewhat irregular; lustre brilliant metallic; specific gravity, 1.404.-
Volatile matter, 7.07 Carbon, 90.23; Ashes, grayish, 2.70.
These analyses will exhibit the average composition of the coal in the different parts of the first or
great southern anthracite basin; the specimens which were selected with this view having been chosen
from various localities, at tolerably regular intervals from near its eastern extremity to within a few
miles of its western termination.
The public are already familiar with the fact of the general increase of softness in the coal of this basin
as we proceed westward. The above results will display a similar augmentation in the quantity of the
volatile materials in the coal, though it does not follow that these two features are in exact proportion
to each other, as a single neighborhood will show beds of coal differing considerably in both these
particulars-the hardness and volatile matter-and when no such dependence of the one upon the other
can be remarked.
From the Lehigh westward, as far as Swatara, we rarely find the volatile matter to amount to more
than about 71 per cent. in the coal; while its average quantity of anthracite generally may be stated
at about 6 per cent. Nearly the whole of this appears to be water. Advancing a few miles west of
Swatara, we enter a section of the basin where the coal acquires a decided increase in the amount of its
volatility.
At Black Spring Gap, twenty-six miles east of the Susquehanna, this is first distinctly manifested
the quantity there being about 10 per cent. A portion of this is probably free gaseous matter, not
bitumen or, if this is present, the quantity is too small to impart to the coal any tendency to melt
or make a coke. But about ten miles westward we meet with coal in the prolongation of the same
veins, having as much as from 10 to 15 per cent. of volatile matter, and a part of this obviously bitu-
minous.
From the Yellow Spring Gap to the western extremity of the basin, the largest proportion of volatile
matter which we have yet noticed in the coal is about 15 per cent. Where it possesses this amount, it
has all the properties of a true bituminous coal, burning with a brilliant though not very enduring blaze;
and yielding, when properly treated, a good spongy coke, well adapted to manufacturing purposes.
Bituminous Coals.-Coal from Hopwell Furnace mines, Broad top mountain, Bedford county.
Massive; strixe distinct, somewhat columnar; shining jet black, in parts iridescent. Ashes in the coal,
4.00. Coke spongy, but hard-Volatile matter, 11.20; Coke, 88.80.
The coal of the broad-top basin exhibits an interesting confirmation of the general law, that as we
advance towards the northwest the coals acquire more and more bitumen. This coalfield occupying a
position intermediate between the range of the anthracite basins on the one hand, and the bituminous
basins beyond the Alleghany Mountain on the other, its coal displays a corresponding or intermediate
proportion of bitumen.
First basin, N. W. of the Alleghany Mountain-Coal from bed of Lick Run, Lycoming Co. Laminated;
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COAL, ANTHRACITE.
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somewhat brittle; shining, black; between laminse, dull black. Ashes in the coal, 13.07 ; grayish pink.
-Volatile matter, 20.72; Coke, 79.28.
Coal from Queen's Run, two miles below Farrand's Ville, Clinton Co. Irregularly columnar; brittle;
color jet black, shining; with thin films of charcoal. Ashes in the coal, 4.60.-Volatile matter, 21.50;
Coke, 78.28.
Coal from Snow Shoe Mine, Centre Co. Massive; brittle; irregular fracture; tendency to columnar
structure; lustre shining, jet black. Ashes in the coal, 2.07. Coke highly intumescent and spongy.-
Volatile matter, 21.20; Coke, 78.80.
Coal from Moshannon Creek, near Philipsburgh, Clearfield Co. Structure small columnar, somewhat
fibrous; striæ distinct; lustre jet black and shining. Ashes in the coal, 6.10.-Volatile matter, 29.50
Coke, 70.50.
Coal from Steed's Mine, sixteen miles from Philipsburgh, Centre county. Friable, irregularly colum-
nar; striæ distinct; jet black, with considerable lustre. Ashes in the coal, 11.20. Coke, compact; ashes,
light cream color.-Volatile matter, 20.40; Coke, 79,60.
Coal from Leech's Mine, 171 miles from Philipsburgh, Centre county. Friable; structure columnar;
jet black, with much lustre. Ashes in the coal, 11.75.-Volatile matter, 20.32 Coke, 79.68.
Second basin, N. W. of the Alleghany Mountain.-Coal from upper part of large bed, Ralston, Ly-
coming county. Columnar; irregular cubical; fracture irregular; color shining; black, in parts dull.
Ashes in the coal, 5.00.-Volatile matter, 20.50; Coke, 79.50.
Coal from Karthaus, upper seam, Clearfield county. Structure columnar; cubical; friable; fracture
irregular; color jet black; lustre considerable. Ashes in the coal, 8.80; brownish yellow.-Volatile
matter, 13.00; Coke, 87.00.
Coal from Karthaus, lower seam; external character similar to the above. Ashes in the coal, 4.70;
brownish yellow.-Volatile matter, 24.80; Coke, 75.20.
Coal from Reed's, six feet vein, Curwinsville, Clearfield county. Columnar; cubical; brittle; fracture
irregular; color jet black, with great lustre. Ashes in the coal, 5.80.-Volatile matter, 27.00; Coke,
78.00.
Third Basin, northwest of the Alleghany range.-Coal from the bed now worked at Bear Creek,
Blossburg, Tioga county. Columnar; somewhat compact; containing occasional thin seams of char-
coal lustre jet black, and very considerable. Ashes in the coal, 5.20.-Volatile matter, 32.00; Coke,
68.00.
Coal from five feet vein, Warner's Caledonia, Clearfield county. Structure laminated; cubical; brit-
tle; fracture irregular; color jet black, and shining. Ashes in the coal, 8.50.-Volatile matter, 37.00;
Coke, 63.00.
Coal from three feet seam, Warner's Caledonia, Clearfield county. Soft columnar; lustre jet black,
and very considerable; fracture irregular. Ashes in the coal, 7.20.-Volatile matter, 38.20; Coke, 61.80.
Coal from Blairsville, large bed, Westmoreland county. Structure laminated; columnar, somewhat
hard and compact; color shining and black. Ashes in the coal, 4.00.-Volatile matter, 31.00; Coke,
69.00.
Fourth or Great Western Basin.-Coal from Sandy Ridge, four miles from Shippensville, Clarion
county. Massive; striæ indistinct; fracture cubical; black; lustre feebly shining. Ashes in the coal,
7.00; light gray.-Volatile matter, 43.20 Coke, 56.80.
Cannel coal from six miles east of Franklin, Venango county. Composed of laminae; breaks with
a uniform clearage; cross fracture conchoidal; surface smooth; dull black; with little lustre. Ashes
in the coal, 17.68.-Volatile matter, 52.78; Coke, 47.22.
Cannel coal from Greensburg, Beaver county. Composed of thick regular laminse; cross fracture
conchoidal; surface smooth; dull black Ashes in the coal, 83.88.-Volatile matter, 36.00 Coke,
64.00.
Coal from Conneant Lake, Crawford county. Slaty; laminated; fracture irregular; somewhat brit-
tle; color jet black, shining. Ashes in the coal, 1.80; reddish brown-Volatile matter, 38.75; Coke,
61.25.
Coal from near Greenville, Mercer county. Laminated; slaty; cross fracture splintery; brittle
shining, jet black. Ashes in the coal, 1.7; brownish yellow.-Volatile matter, 40.50 Coke, 59.50.
Coal from near Orangeville, Mercer county. Structure, laminated; somewhat rusty between laminae;
fracture regular; color black, sometimes shining and iridescent. Ashes in the coal, 2.80; dark brown.
-Volatile, 43.75; Coke. 56.25.
A comparison of the foregoing analysis of the bituminous coals, from the several basins northwest of
the Alleghany Mountain, discloses the highly interesting general fact of the progressive increase in the
quantity of their bitumen, as we advance northwestward. Thus, the first group of coals, selected from
various parts of the basin nearest the Alleghany Mountain, shows an average proportion of bitumen of
about twenty-one per cent.; the second, or next basin to the northwest, A somewhat higher proportion
the third basin, or range of basins, gives as much as thirty-four per cent.; and the fourth, or great
western basin of the Alleghany and Monongahela, nearly forty per cent. This remarkable change in
the composition of the coal, as we proceed from the southeast to the northwest, is not confined only
to the basins of Pennsylvania, but prevails, it is believed, throughout the whole length of the vast
bituminous coal field, which ranges from the state of Pennsylvania to the northern boundary of Ala-
bama.
All the varieties of coal contain more or less sulphur, no doubt in combination with iron, under the
form of iron pirites, disseminated throughout the coal. From numerous chemical examinations, the fol-
lowing results are selected :-
Anthracite coal from Pottsville; average specimen of white ash. Contains in 100 parts, sulphur 0.60.
Anthracite coal from Peach Mountain; average specimen of red ash. Contains in 100 parts sul-
phur 0.48.
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CORN-SHELLER.
'Anthracite coal from Lehigh, (hard coal ;) average specimen of white ash. Contains in 100 parts,
sulphur 0.91.
Bituminous coal from Karthaus ; highly bituminous. Contains in 100 parts, sulphur 2.70.
Bituminous coal from Blairsville, Westmoreland county. Contains in 100 parts, sulphur 2.60.
The limited use of anthracite in England may be attributed to the greater facility of working bitu-
minous coal, and to the fact that the latter is nearer the great markets of its consumption. An un-
founded prejudice existed against it, excited, probably, by the circumstance that it kindles less readily
than the other, and it was thought unadapted to any other purposes than those above-mentioned.
The rapid increase of steam navigation, the high price and growing scarcity of wood in the northern
states, directed attention to the vast beds of coal with which various parts of the United States
abound, and particularly the state of Pennsylvania.
Anthracite being nearest the seaboard was the first to come into the market, and to the people of
Pennsylvania must be attributed whatever of merit belongs to its successful introduction.
In the course of the year 1831, anthracite began to be used in many of the cupolas of the iron-found-
ries of Philadelphia, but only in combination with an equal quantity of charcoal; the prejudice I have
mentioned not being confined to England.
Thus it continued for some years after, during which period it had come into general use for domestic
purposes, by the entire population of the towns and cities on the coast; it had also been adopted for
the generating of steam for stationary, locomotive, and marine engines, for the smelting of copper, the
manufacture of glass, and for all the processes of the iron manufacture, as smelting, puddling, heating
the blooms, lumping, also for the smith's forge.
In all these operations the fuel now in use is anthracite anthracite only.
Its introduction has given a sensible impulse to steam navigation in the northern lakes and rivers.
In respect of economy of space, indeed, it is now determined, that anthracite has an advantage over
bituminous coals; an advantage of great importance in ocean steamers.
One of the most remarkable facts to be noticed in relation to the consumption of anthracite is its
cleanliness; it burns without smoke.
The contrast it makes in this respect with bituminous coal is strikingly apparent to travellers.
1005.
R
M
H
A
S
CORN-SHELLER. This machine is the invention of L M. Whitman, and is now the property of
S.G. Wise, of Weedsport, Cayuga Co., N.Y. It possesses the property of shelling corn with wonderful
rapidity, and cleans the grain by removing all dust, &c., by a blower at one operation.
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323
Fig. 1005 is a perspective view, and Fig. 1006 is a vertical section, that is, as viewed looking down
upon the top of the machine, only the frame P in Fig. 1005 is omitted in Fig. 1006, to show the parts
to better advantage. The same letters in both figures refer to like parts, and the reader must refer to
both in perusing this description.
A is a frame made in the usual form, or of any other more suitable. B is a concave bed made of
cast-iron plates, with projections on their inside surfaces. D is a cast-iron cylinder having projections
cast on its outside surface, and by the ears of corn being fed in between the roller and the concave bed
through M, on the other side of the lid R, and the cylinder set in motion, the ears will be carried round
between the cylinder and concave bed, and all the corn removed from the cob in a most excellent man-
ner; and when it is carried round to the rake-teeth seen above DD, the cob is thrown over the frame P,
and falls over the side of the machine. The concave bed is hung on strong springs EE, which allow it
to spring to the various sizes of the ears of corn-making it flexible for that purpose. The plates C,
which form the concave bed, are placed a small distance apart from one another, so that the corn falls
down between them into an inclined conduit, which carries the corn below H, a revolving set of fans,
where the grain is perfectly cleaned; the dust, &c, being blown out through an opening below S,
and the corn being heavier passes into the granary or receptacle out of the opening T.
1006.
M
E
E
H
L
A
Operation.-The ears of corn are placed in the hopper M, best seen in Fig. 1006, and the master
wheel K is turned, which driving the small cog wheel I, turns the revolving cog-surface cylinder D, and
carries the ears of corn between it (the cylinder) and the concave bed B, when, by the action of the
rough surface of the cylinder and concave bed upon the ear of corn, the grain is effectually removed
from the cob, as the ear is carried from one side to the other of the concave bed. And by the concave
bed being attached to springs, it will be observed, that according as the ears are great or small, and
also as they get smaller in their progress of shelling, the exact relative distance to remove the corn from
the cob will be maintained between the revolving iron cylinder and the concave bed.
This is a very important and valuable part of the invention. It shells the corn rapidly, and its work
is both clean and satisfactory.
COROSOS, or nut ivory. See WOODS, varieties of.
COTTON, quantities of tabulated. See QUANTITIES.
COUNTER See DIMENSIONS OF STEAM-ENGINES.
COUNTER PROPORTIONAL by W.H. Lindsay. The construction and operation of this instru-
ment will, with the aid of the drawing, be readily understood.
Whatever distance or quantity a space from point to point, as from 3 to 4 on the outer circle of the
dial-plate, is intended to represent, is attained by proportioning the arm " 2, and the segment of toothed-
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COUNTER PROPORTIONAL.
wheel v, to the length of the stroke made by the rack r. To facilitate the adjustment with the greatest
accuracy, the radius of the counter-arm 76 2 can be lengthened or shortened by means of the pin W, which
can be shifted up or down in the slot; and when the proper distance is obtained, made fast by a nut on
the back side of the arm. The ratchet-wheel c, and centre pin e, which passes through an eye in the
shoulder of the cross-piece k, on the frame b, give motion to the dial hands. The ratchet-wheel is
moved in proportion to the length of stroke communicated to the counter-arm n 2, by means of four or
five pawls or catches f, each a little longer than the other: for instance, if the space between two teeth
on the ratchet-wheel be divided into four equal parts, and four or five pawls are used, they are each
longer than the other by that distance; by which means, one or more of the set are always in contact
with the tooth nearest their points, thereby obtaining a continuous bearing or hold of the ratchet-wheel,
without the possibility of the least slip or play. The moveable pawls f all work on the same centre or
pin on the arm d, which works on the same centre as the ratchet-wheel The pawls are made of steel;
their points are kept in contact with the tooth nearest to them, by means of the curved elongation of
each pressing against the pin h1 on the off-side of the arm, to prevent the least slip or return of the
ratchet-wheel during the back travel of the arm with the pawls, or whilst the pawls are moving back
over the teeth. Catches g, of the same construction and number as those on the arm, are placed on the
frame b, working on a pin in it, so that their ends are pressed into the space between the two nearest
teeth on the ratchet-wheel, to render the stop-catches more effective. The ends of the spring i, which
is a piece of brass bent or curved, and slit into as many pieces as there are catches for it to act on,
presses against the curved part of the catches. The guard 1 crosses the arm d, keeping the arm and
catches steady when moving. The pin m, in the centre of the arm, passes through the alot in the back
of the counter, to which the counter-arm is made fast by a nut.
1007.
1008.
do
The counter's operation requires but little explanation: the length of stroke of the rack being deter-
mined, say 12 inches, and the pin in the slot adjusted by that length of travel, 50 that the hand on the
outer circle of the dial-plate exactly makes a space, as from 3 to 4. Whatever distance within 12
inches the rack moves forward, say 3, 5, 8, or 10 inches, it will give motion to the ratchet-wheel and
hand only in that proportion, the stop-catches allowing the ratchet-wheel to move round during the
forward motion of the rack; but on the back travel of the rack-arm and catches, they being pressed by
their own as well as the springs i into the space between the teeth nearest their ends, prevents not
only the return of the ratchet-wheel, but also the least slip or return, by which means the face hands
remain where they were carriod to during the forward motion of the rack; from which it will be seen
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CRACKER AND BISCUIT MACHINE.
325
that whatever the index, or from point to point on the outer circle represents, whether distance or quan-
tity, by communicating motion to the rack a given distance, it will, on inspection of the dial-plate at any
time, be found what has been performed.
COUNTERFORTS. See RAILWAY ENGINEERING.
CORROSION OF BOILERS. See BOILERS, and DETAILS OF ENGINES.
COVER ON SLIDE-VALVE, required to produce a given expansion. See PROPORTIONS and PROP-
ERTIES OF THE STEAM-ENGINE
CRACKER AND BISCUIT MACHINE. It is highly important where large quantities of biscuit
are made for sea, either for the commercial or war marine, that there should be some machine for the
speedy preparing of such kind of provisions, so as to preserve the flavor and quality of the flour, which
we well know is not the case with all kinds of bread, as some will not keep fresh longer than two or
three days. The machine represented in the engraving was patented some years ago by W. R.
Nevins; and although there have been a number of machines built for the same purpose, yet good
judges have pronounced it to be the best machine of the kind in existence, and in its present im-
proved condition, without a rival. One of these machines was put up at St. Augustine during the Florida
war, and it was of great benefit to the troops there. It has been examined by commissioners of the
British navy, and has met their entire approbation. The Brazilian government has also requested one
to be sent them, and there are others in use at Norfolk, Va., and Louisville, Ky.
1009.
R
L
Description.-A A A A is the frame. B B are two feeding-rollers, the dough being fed into them on
the board C. DD is an endless band the same width as the feed-rollers. This band is for carrying the
dough from the feed-rollers to the cutters and forward off the cutters on the band-frame Y, to be taken
off after the dough is cut into the desired size and form. The frame Y, on which the band D runs over
the roller C, can slide under the machine when the machine is not in operation, 80 as to occupy as little
room as possible. P is a crank for working the machine, and on the crank-shaft is a cog-wheel O,
meshing into a larger cog-wheel N. The cog-wheel N moves the cutters, not in a rotary motion, but up
and down, cutting the biscuit clean by the reciprocating motion ingeniously combined with the rotary
by two eccentrics on the shaft, which will be observed between N and the larger, or fly-wheel, on the
other side of the frame. While the cutters are moved by N, the shaft of o gives motion to the cog-
wheels on the other side of the frame, and by the accumulation of power on the fly-wheel the whole
apparatus is very easily worked. The cog-wheel G meshes into the cog-wheel R, for the purpose of
giving the feed-rollers a uniform speed, something very necessary, as bakers know, so that there may
not be too much friction by the rollers, in which case crackers and biscuits are afterwards apt to split
open, and in warm latitudes soon spoil. The endless band is made to bring forward the dough by two
cranks, one seen on the opposite side of the frame, inside of the fly-wheel, which works a pendulum
shaft below the handle P, on which is a cord passing over a pulley at the end of the feed-board C; on
the end of this cord is a weight which works by the pendulum the toothed pulley, on which is a clamp
to slip and cut the exact distance the band is wanted to move for every cut of the cutters, for the band D
passes over the roller of the toothed pulley, on which is the cord, and round by C. There is a slot in
the pendulum shaft, 80 that the pin can be moved up or down, for a long or short cut, and by the shifting
or changing the tooth-wheels o and N, the speed of the cutters will be increased while the rest of the
machine keeps a uniform motion. It will be observed that the cutters do not fall or press down upon
the canvas direct from the shaft, there is a plate between the canvas and the cutters, so that a fine
clean cut is made through the dough.
One of these machines with cutters only for three biscuit in the breadth of the frame, has cut as fast
as one in use in the British navy with fifty cutters, thus showing a great superiority. But the best
recommendation comes from those who have them in operation, Mr. Stratton, of Brooklyn, and Mr.
Wilson, of this city. who speak in the highest terms of their qualities. This machine is the invention of
Mr. W. R Nevins, No. 609 Greenwich-street, New York, who manufactures them.
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CRANE, MOVEABLE.
CRANE, MOVEABLE. Arranged and used for laying the voussoirs in the inverted arches of the
United States Dry Dock at Brooklyn, New York, by Wm. J. McAlpine, predecessor to Mr. Stewart, the
present Chief Engineer.
1010.
18 X 76
186
279
$
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13x12
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12x13
1011.
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5.7
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27.9
16ft
12x13
17%
20 ft
SCALE.-8 feet=1 inch.
This crane has been used for hoisting stone weighing from ten to fifteen thousand pounds, at the
extremity of the arm, which describes a circle of fifty feet diameter. It has also been used with an out-
rigger, by which stones from three to five tons weight were hoisted ten feet beyond the extremity of
the arm.
A similar crane was used by the same engineer in the construction of the locks of the enlarged Erie
Canal A moveable sheave traversed along the arm of the crane, which was laid on an inclination
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ORANE, FOUNDRY.
327
towards the mast of twenty degrees. By the use of the "Siamese blocks," the stone is moved towards
or from the mast, and hoisted or lowered with the accuracy requisite for setting fine-cut stone.
CRANE, Foundry. The accompanying engraving exhibits the best description of foundry-crane
yet invented. It is manufactured by W. A. Burke, of the Lowell Machine-Shop, Massachusctts.
Fig. 1012 is a side elevation, and Fig. 1013 an end elevation.
&
1012.
J
H
B
8
K
M
10.
N
H
1013.
C
R
CRANK: theory of,-Supposed loss of power from use of ; strength of malleable-iron cranks,-Ta-
bles of strength of cast-iron cranks,-Rules for strength of malleable-iron cranks,-Rules for strength
of cast-iron cranks. See MECHANICAL POWER OF STEAM.
CROSS-HEAD. See DETAILS OF ENGINES.
CULVERTS. See RAILWAY ENGINEERING.
CURVES. See RAILWAY ENGINEERING.
CURVILINEAR TOOLS: Simple and Complex, for mouldings both external and internal. See
TURNING TOOLS.
CUTTER-BARS. See BORING TOOLS.
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CUTTING AND CARVING MACHINERY.
CUTTING AND CARVING MACHINERY. Machinery and Apparatus for Cutting and Carving
Substances to be applied for Inlaying and other purposes.-This invention consists in certain improved
constructions or arrangements of machinery, having a revolving cutter, by means of which, in conjunc-
tion with a moveable table, tablets of wood and other materials can be cut away, carved, countersunk,
and perforated, in various ornamental forms, with great facility, for the production of inlaid devices,
gothic tracery work, and other kinds of ornaments hitherto usually wrought by hand.
1014.
c
U
s
1015.
1017.
1019.
1021.
1020.
1018.
K
.
1016.
H
II
8
Fig. 1014 represents a side elevation; Fig. 1015, an end elevation; and Fig. 1016, a horizontal view
of the machinery. AA is a bench or table, for supporting the several parts of the machine; BB is a
standard or bracket-frame, firmly fixed to the said bench; which frame is provided with plummer-
blocks and bearings CC, to receive a spindle D. E is a forked frame or swinging arm, firmly fixed
upon the spindle D; and the other end of the arm E is furnished with suitable bearings, which carry,
in a vertical position, a spindle F. The lower end of this spindle F is formed to receive a chuck V, or
other suitable contrivance, for attaching and holding securely the tool, drill, or cutter X, or such other
cutter as may be required; and upon the spindle F, near its upper end, is fixed a conical pulley G,
having grooves of different diameters, for the purpose of determining the velocity with which the spindle
shall be made to revolve. This pulley is designed to receive an endless band or cord H, which passes
round the lower part of a similar pulley I, running loosely upon the spindle D; the upper groove of
the pulley I is made to receive another endless band or cord K, that passes around a wheel or drum L,
supported by a standard or frame N, which is connected by a similar frame M, to the standard B; but
the band K may be driven by any other means. o is a horizontal moveable table, mounted upon a
vertical shaft R, which passes through the bench A; its lower end being supported by, and turning
freely upon a step or bearing S, in the arch Z, fixed to the framing of the bench. The tablet or slab
of wood, or other material intended to be wrought by the cutter X, is to be placed upon the turning-
table as at P, and made fast thereon by screwed clamps. At the left-hand end of the bench A, there
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CUTTING-ENGINE.
329
is a vertical bar J made fast to the wood framing, in which there is a fulcrum-pin for the lever W to
turn upon; one end of this lever W is formed into a concave socket to receive, as a step, the lower end
of the spindle D before mentioned, and the other end of the lever is connected by a joint with a
treadle-rod T. This treadle-rod and lever are for the purpose of raising, when required, the spindle
D, with the forked frame E, carrying the drill. U is an adjustable screw set in the leg of the bench
as a stop to the lever, intended to regulate the descent of the spindle D with the frame E, in order
that the cutter X shall not penetrate deeper into the material or substance P than may be desired.
Fig. 1021, and the part dotted in Fig. 1015, represent another arrangement for raising and lowering
the spindle D with the forked frame and drill, instead of the lever and treadle-rod before described:
this arrangement is used when the carving of variable relief, such as foliage, figures, &c., is required to
be executed.
Upon any convenient part of the standard B is fixed a frame a, with bearings b b to receive and
support the axle of a quadrant c, which has a lever d attached to its centre. From the periphery of
the quadrant c is suspended by a chain e, or other suitable contrivance, the spindle D, carrying the
forked frame E with the drill. To the lever d a weight f is suspended by a rod, or other convenient
means, hung in any of the notches provided in the lever for that purpose; which weighted rod acts as
a counter-balance to the spindle D and the several parts attached thereto, thus enabling the cutter X
to be raised or lowered with the greatest facility and precision; all the other parts of the machine, and
their action, being the same as hereinbefore described.
Fig. 1017 is an elevation, and Fig. 1018 an under-side or end view, of a tool or cutter for cutting or
carving a semi-circular or quarter-round hollow, for mouldings, gothic tracery, dic. Fig. 1019 is an ele-
vation, and Fig. 1020 an under-side or end view, of a tool or cutter for cutting or carving a bed and
fillet, or astragal. These are only two examples of cutters, but of course a great variety may be
employed, and these must depend upon the form of the edge of the recess intended to be cut or formed
as any and every variety of rounds and hollows, ovolos, agees, &c., separately or combined, may be
executed, not only in straight lengths, but to the form of any regular or irregular curve that may be
desired.
The mode of cutting or carving with this machine is as follows:-Upon the revolving table O, the
tablet, slab, or piece of wood, or other material P to be cut or carved, is fixed and on its upper surface,
when desired, is placed a template or pattern Q, (formed of iron, brass, or other approved material,) of
the design required to be cut or carved; and the two are firmly held upon the table o, by cramps or
cramping-bars, as shown. Motion being given by any convenient power to the wheel or drum L, or
communicated by any other means to the band or cord K, the pulley I will be made to turn rapidly
upon the spindle D; by which means the band or cord H passed round the pulley G will cause the
spindle F carrying the cutter X to revolve with great speed, the velocity of the cutter being deter-
mined by the proportions which the diameters of the pulleys G and I bear to each other, and the speed
of the driving power. The cutter X being set to the depth of cut required by adjusting the stop U,
the workman passes down the treadle-rod T with his foot, which causes the lever W to raise the spindle
D with the cutter X, and the several parts attached thereto: thus the forked arm E is raised, and being
moved around the cutter X, may be passed over the tablet P in an arc; at the same time the moveable
table o must be turned, 80 that the cutter may be perpendicularly pendent over the part of the tablet
where the work is to commence. The revolving cutter X is then let down, by removing the pressure
from the treadle-rod T, and it immediately penetrates into the tablet. The form in which the cutter
moves over the tablet is now to be determined by guiding the shaft of the cutter against the edges of
the template or pattern; the table O, with the tablet P upon it, being moved at the same time, in order
to keep the edge of the template always close to the shaft of the cutter. By thus moving the swing-
ing-frame E and the table O, various arcs of circles that are constantly tangental to each other may
be traced upon the tablet under operation; thereby enabling every possible variety of regular and
irregular, curved, and straight forms to be cut or carved in the material acted upon; and this combined
or simultaneous action forms the principal novelty of the invention.
The patentee claims the combination and application of the several parts as herein shown and de-
scribed, and any variation of that combination or application for effecting the principle of his invention
provided the swinging-frame which carries the cutter, and also the table on which the article to be
wrought is placed, have both the means of circular motion.
CUTTING-ENGINE Mr. Joseph Gaume, of Cincinnati, Hamilton County, Ohio, has invented a new
and useful improvement in the Cutting-Engine, or machine for dividing and cutting the teeth of cog-
wheels. In the accompanying engravings, Fig. 1022 is a plan. Fig. 1023 a side elevation, and Fig. 1024
a front view. The same letters indicate like parts in all the figures.
The leading object of this invention is to adapt the common lathe, by the addition of certain parts, to
the cutting of cog-wheels, chiefly for the use of small shops and manufactories where a lathe and cutting-
engine are only required occasionally. And the nature of the first part of his invention consists in add-
ing to a lathe, and in combination with the mandrel thereof, a puppet made in two parts for carrying
the cutter, the lower half to be attached in the usual manner to the bench, and connected with the upper
one by an inclined plane, that the upper part may slide on the lower one at an angle of forty-five or
any other number of degrees, for the purpose of carrying the cutter or curr over the wheel in the oper-
ation of cutting the cogs of bevel-wheels. The second part of his invention consists in combining with
this puppet the cutter-frame, which carries the spindle of the cutter or curr by means of an adjustable
horizontal slide, on which the cutter-frame moves to and fro to carry the cutter over the wheel in
which the cogs are to be cut; the said slide being a plate with dove-tail or other formed edges, em-
braced by or embracing the cutter-frame, and attached at one end by a fixed bolt to the top plate of the
puppet, and at the other by a screw bolt that passes through a curved slot, whereby the cutter-frame
may be made to carry the cutter in its horizontal motion diagonally with the axis of the mandrel for the
cutting of diagonal cogs: the spindle of the cutter or curr having its bearings in an adjustable slide
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CUTTING-ENGINE
that moves at right angles to the mandrel, to bring the cutter over the axis of the mandrel, (the bed of
the slide being connected with a vertical side in the cutter-frame to adapt the cutter to wheels of differ-
ent diameters,) by means of a fixed bolt on one side and a screw-bolt passing through a curved slot on
the other, that the axis of the cutter may be placed at any angle with a vertical line. The third part
of the invention relates to the method of dividing the cogs, and consists in placing the index-wheel on a
slide, that it may be adjusted to a wheel of any desired number of cogs on an arbor that communicates
by a screw or its equivalent to the mandrel which carries the wheel to be cut, 80 that, by merely chang-
ing the wheel on this arbor, a single division index may be used for the cutting of any desired number
of cogs. The fourth part of the invention consists in combining the dividing apparatus with the mandrel
of a lathe, by means of cogs on the pulley of the mandrel or on the mandrel, the dividing apparatus be-
ing 80 arranged that it can be thrown in and out of geer. In the accompanying drawings a represents
the bench of the lathe, and C the mandrel with its set of cone pulleys c, the face of the larger one of
which is a crown cog-wheel d, the cogs of which engage with the threads of an endless screw on arbor e ;
the threads of the screw are shown by dotted lines in the plan, Fig. 1022. One end of the arbor runs
on the point of a pivot-screw f, and the other has a long journal that runs in a box in a standard g
attached to the bench or the puppet head of the mandrel, 80 that when the rear end is liberated from
the pivot-screw, the arbor can be moved far enough in the standard g to carry the ends of the screw
out of the cogs of the crown-wheel, that the mandrel may be used for turning the cog-wheel: in this way
the wheel can be made with great accuracy, for it is turned and cut on the same mandrel, and therefore
there is no danger of not having the wheel properly centered. When the wheel is to be cut, the acour e
is properly mounted, and its outer end is adapted by a collar and nut to receive a spur-wheel j of any
desired number of cogs, which take into the cogs of the wheel K, one face of which is provided with the
division plate or index b, and the other end with a handle m for turning it. This wheel is fitted to and
turns on a stud-pin n, projecting from plate o, that slides on an arm p of the standard g, that it may be
set to the proper pitch line of a wheel of any desired size on the arbor e, and there held by a screw q.
A spring point or catch T is used to catch in the notches of the index or division plate b.
From the foregoing it will be seen that with any given size of wheel on the arbor e, the number of
cogs to be cut may be varied by the motions of the dividing or index wheel, as in the ordinary dividing-
engine, and that, by changing the wheel on the arbor e, any variation can be given to these divisions.
The wheel having been turned and the dividing apparatus put in connection, the centering puppet head
8 of the lathe is thrown back, and the extra puppet t is secured in place on the bench. This puppet is
made in two parts, (tt,) connected together by a dove-tail or other slide и at an angle of 45°, or any
other number of degrees with the plane of the bench. The lower half t is secured to the bench, and
the other (t) can be made to slide on it by means of a handle or lever v that turns on a fulcrum-pin W
attached to the lower half, and connected with the upper half by a pin X that passes through a slotted
hole in a well-known manner. The top plate of the upper half is in a plane parallel with the mandrel,
and has a dove-tail slide y connected with it at the forward end by a fixed bolt z, (see Fig. 1025, which
is a plain view of this part,) and at the other end by a screw bolt (a) that passes through a curved slot
(see the dotted line) in the top plate, so that any horizontal inclination desired may be given to this slide
which is embraced by the bottom plate H of the cutter-frame, (c,) and which can be made to slide thereon
by a handle or lever (d) that turns on a fulcrum-pin attached to the puppet and connected with the cut-
ter-frame by a joint-link, (e,) so that by the motion of this lever the attendant carries the cutter to and
fro horizontally over the edge of the wheel to be cut, for cutting spur cogs in a direction parallel with
the axis of the mandrel, or inclined therewith as the slide may be set, to be indicated by a pointer (f) on
the cutter-frame, and an index (g) on the top plate of the puppet. But when the machine is used for
cutting the cogs on bevel-wheels, then the cutter-frame is carried by sliding the upper part (t) of the
puppet head on the lower part Fig. 1025; the inclination of this slide determining the bevel of the
cogs cut. The forward part of the cutter-frame has a plate, (h,) that alides in it vertically by means of
a screw, (h,) to adapt the cutter to any desired diameter of wheel to be cut; to this is connected another
plate (j) that turns on a bolt, and further secured by a screw-bolt (k) that passes through a curved slot,
(1,) by means of which the plate (j) may be turned on the fixed bolt as a centre to give any desired in-
clination to the axis of the cutter; and this last-named plate is provided with dove-tail ways in which
alides the cutter-carrier (m,) which is a frame in which are the bearings of the spindle (n) of the cutter,
(o,) so that this may be regulated endwise by a set screw (p.) The cutter is rotated by a belt (q) that
passes from any first mover over a pulley (r) on the spindle. From the foregoing it will be seen that
the cutter can be adjusted in any direction relatively to the axis of the mandrel that carries the wheel
to be cut, and that, by means of one of the handles or levers, the cutter-frame can be moved to and
fro to cut the cogs by sliding the cutter-carriage on the puppet in a horizontal plane parallel with the
axis of the mandrel, which, by the adjustment of the ways or slide on the puppet, may be adjusted to
move in a vertical plane projected from the axis of the mandrel or at any inclination therewith to cut
oblique cogs; or, by means of the other handle, that the cutter-frame may be made to move with the
upper part of the puppet on an inclined plane to cut the cogs of bevel cog-wheels. It will be obvious,
from the above, that the plan of the junction of the two halves of the puppet may be made at any in-
clination desired to suit the bevel of the wheel intended to be cut.
What he claims as his invention and has secured by letters patent, is making the puppet which car-
ries the cutter-frame in two parts, separated by an inclined plane, that one may slide on the other for
cutting the cogs of bevel-wheels, in combination with the cutter-frame that slides thereon; and also the
cutter-frame and double puppet combined together in combination with the mandrel of the lathe. He
also claims the method of adapting the index or division plate that has but one set of divisions, to any
division of cogs desired to be cut, by means of shifting the wheel on the arbor that communicates motion
to the mandrel, in combination with the sliding connection of the index or division wheel, whereby nu-
merous divisions on the index plate are avoided. And further, he claims the dividing apparatus in
combination with the mandrel of a lathe by means of the cog-wheel and pulleys put on one end of the
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CUTTING TOOLS.
same mandrel, whereby the wheels to be cut can be turned and cut on the same mandrel without being
removed therefrom to insure good work, and whereby also the turning-lathe may be used for a cutting-
engine.
This machine may be composed either of a single lathe, or of a complicated one, of any desired dimen-
sions, and nothing need be added to it but a side-coupling, to form the division.
First. Its advantages are: turning the wheel on its points; it is thus cut on these same points, with
the axis, the length which may be placed on the lathe; likewise, by turning the wheel on the flat side,
the hole in the centre and the circumference are cut without its being removed.
Second. This machine can cut a wheel on the circumference obliquely, to the right or left, with any
desired inclination; and also the same with regard to the wheel on the side.
Third. The wheel can be cut at an angle of forty-five degrees. This machine can take the place of,
and even offers more advantages than the Great Platform." It can be constructed of any dimension,
always being able to cut the wheel which can be turned on the lathe, even should it be fifteen feet in
diameter. This machine can be adapted to a lathe placed upon a wooden bench, with only one hun-
dred and fifty pounds additional weight of castings. This cutting machine may be obtained, with all
the above-mentioned advantages, from one inch in diameter to two feet. The cast-iron lathe offers more
solidity, and with a little additional expense. The division extends to all numbers with the greatest
precision.
CUTTING AND PUNCHING MACHINE See PUNCHING AND CUTTING MACHINE.
CUTTING TOOLS, general remarks upon. Cutting tools may be included in three groups, namely,
Paring Tools, Scraping Tools, and Shearing Tools.
First. Paring or splitting tools, with thin edges, the angles of which do not exceed sixty degrees; one
plane of the edge being nearly coincident with the plane of the work produced, (or with the tangent, in
circular work.) These tools remove the fibres principally in the direction of their length, or longitudi-
nally; and they produce large coarse chips or shavings, by acting like the common wedge applied as a
mechanical power.
Secondly. Scraping tools with thick edges, that measure from sixty to one hundred and twenty de-
grees. The planes of the edges form nearly equal angles with the surface produced; or else the one
plane is nearly or quite perpendicular to the face of the work, (or becomes as a radius to the circle.)
These tools remove the fibres in all directions with nearly equal facility, and they produce fine dust-like
shavings by acting superficially.
Thirdly. Shearing or separating tools, with edges of from sixty to ninety degrees, generally duplex,
and then applied on opposite sides of the substances; one plane of each tool, or of the single tool,
coincident with the plane produced.
In explanation of these views, the diagram, Fig. 1026, is supposed to represent seven different tools,
the bevels or edges of which are all at the angle of sixty degrees; this may be considered as the medium
angle of the paring, scraping, and shearing tools.
The cutting and scraping tools are supposed to be moving from A to B, which line represents the face
of the work; or the tools may be considered to be at rest, and the work to be moving from B to A.
Or, in turning, the tool may be supposed to remain fixed, and the circle to represent the moving sur-
face of the work; one plane of the tool then becomes a tangent or radius.
The shearing tools, if in pairs, are proceeding towards each other on the line CD, whilst A B still
represents the face of the work. The single tools act on the same principle, but the body of the mate-
rial, or the surface of the bench or support, supplies the resistance otherwise offered by the second tool.
The tools a f are bevelled or chamfered on both sides, the others from one side only; in these lat-
ter, the general face of the tool forms the second side of the angle, and allowing for exaggeration, both
as to excess and deficiency, the diagram may be considered to represent the edges of the following tools.
[a bcd, Splitting and Paring Tools, proceeding from A to B.]
a, The axe, or the cleaver for splitting.
b, The side hatchet, adze, paring and drawing knives, paring chisels and gouges, the razor, penknife,
spokeshave, the engraver's graver, and most of the engineer's cutting, turning, and planing tools for
metal
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1026.
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c, The turning chisel for soft wood, the chipping chisels for iron, stone, &c.
d, The joiner's chisels and carving tools, used with the bevels downwards, the joiner's planes, the
cross-cut chisel for metal, and some other metal tools.
[ef. Scraping Tools, proceeding from A to B.]
e, When single, the scraping tools for turning the hardwoods, ivory, and brass, the hand-plane for
metal: and when multiplied, the various saws and files.
f, When single, a triangular scraper for metal; and when multiplied, the cross-cut saw for wood, and
also polygonal broaches or rimers with any number of sides, for metal
[e Shearing Tools, proceeding from C to D.]
e, When duplex, shears with edges from eighty to ninety degrees, commencing with delicate lace
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scismors for single threads, and ending with the engineer's shears for cutting iron bars and plates up-
wards of one inch thick; also duplex punches with rectangular edges, for punching engines and fly-
presses.
e, When single, the carpenter's firmer and mortise-chisels, the paring-knife moving on a hinge, and
cutting punches for gun-wadding and thin materials.
f, When duplex, common nippers for wire; more generally, however, the blades are inclined 80 that
one bevel of each blade lies in one and the same plane, and which is vertical to A B, as at g g.
f, When single, the smith's cutting-off chisel.
In practice, the tools differ from the constant angle of sixty degrees, assumed in the diagram for the
convenience of explanation, as the angles of all tools are determined by the hardness and the peculiar-
ity of fibre or structure of the several substances upon which they are employed. The woods and soft
fibrous materials require more acute angles than the metals and hard bodies; and the greater or less
degree of violence to which the tools are subjected, greatly influences likewise the angles adopted for
them.
Thus, under the guidance of a little mechanism, the thin edge of a razor, which is sharpened at an
angle of about 15 degrees, is used to cut minute slices or sections of woods, in all directions of the grain,
for the purpose of the microscope. But the carpenter and others require more expeditious practice, and
the first change is to thicken the edges of the tools to range from about 20 to 45 degrees, to meet the
rough usage to which they are then exposed, whether arising from the knots and hard places in the
woods or the violence applied.
In tools for iron and steel from 60 to 70 will be found a very common angle, in those for brass 80 to
90, in hexagonal broaches for metal it increases to 120, and in the octagonal broach sometimes employed
the angle is still greater; in the circular broach required by clock and watch makers, the angle disap-
pears and the tool ceases either to cut or scrape, it resolves itself into an instrument acting by pressure,
or becomes a burnisher.
To a certain extent, every different material may be considered to demand tools of a particular angle,
and again the angle is somewhat modified by the specific mode of employment: these conditions jointly
determine the practical angles suited to every case, or the angles of greatest economy or most pro-
ductive effect.
The diagram shows that, independently of the measure of the angle of the tool, we have to consider
its position as regards the surface of the work, the broad distinction being that, in the paring tools, the
one face of the wedge or tool is applied nearly parallel with the face of the work; and in the scraping
tools, it is applied nearly at right angles, as explained in the foregoing definitions. Indeed the paring
tools, if left to themselves, will in some cases assume the position named; thus, for example, if we place
a penknife at an elevated angle upon a cedar pencil, and attempt to carry it along as a carpenter's
plane, the penknife, if held stiffly, will follow the line of its lower side and dig into the wood; but if it
be held slenderly, it will swing round in the hand until its blade lies flat on the pencil, and it will even
require a little twisting or raising to cause it to penetrate the wood at all. This disposition appears to
be equally true in the thin edges of the penknife or razor, and in the thick edges of the strong paring
tools for metal.
The action of a cutting tool in motion is two-fold. The moving force is first exerted on the point of
the wedge, to sever or divide the substance particle from particle; the cohesion of the mass now directly
opposes the entry of the tool, and keeps it back. But the primary motion impressed on the tool having
severed a shaving, proceeds to bend or curl it out of the way; the shaving ascends the slope of the
wedge, and the elasticity of the shaving confines the tool in the cleft, presses it against the lower side,
disposes it to pursue that line, and therefore to dig into the substance.
The Forms and Motions of Tools, as regards the production of Lines, Superficies, and Solids.-The
principles of action of all cutting tools, and of some others, whether guided by hand or by machinery,
resolve themselves into the simple condition, that the work is the combined copy of the form of the
tool, and of the motion employed. Or in other words, that we exactly put into practice the geometrical
definitions employed to convey to us the primary ideas of lines, superficies, and solids; namely, that the
line results from the motion of a point, the superficies from the motion of a line, and the solid from the
motion of a superficies.
It therefore follows, as will be shown, that when the tool is a point having no measurable magnitude,
that two motions must be impressed upon it, one equivalent to the breadth, and another equivalent to
the length of the superficies. When the tool is wide, so as to represent the one dimension of the super-
ficies, say its breadth, then only one motion is to be impressed, say a motion equivalent to the length of
the superficies; and these two are either rectilinear or curvilinear, accordingly as straight or curved
superficies are to be produced.
To illustrate this in a more familiar way than by the ideal mathematical conceptions-that a point is
without magnitude, a line is without breadth, and a superficies without thickness-we will suppose these
to be materialized, and to become pieces of wood, and that the several results are formed through their
agency on soft clay.
Thus supposing g g to be two boards, the edges of which are parallel and exactly in one plane, and
that the interval between them is filled with clay; by sliding the board p along the edges of gg, the
point in p would produce a line, and if 80 many lines were ploughed that every part of the clay were
acted upon by the point, a level surface would at length result. The line 1, such as a string or wire,
carried along g y, would at one process reduce the clay to the level of the edges of the box.
Either the point or the line might be applied in any direction whatever, and still they would equally
produce the plane, provided that every part of the material were acted upon; and this, because the
section of a plane is everywhere a right line, and which conditions are fulfilled in the elementary
apparatus, as the edges of gg are straight and give in every case the longitudinal guide, and with 1
the second line is formed at once, either with a string, a wire, or a straight board; but in P the point
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CUTTING TOOLS.
requires a second or transverse guide, and which is furnished by the straight parts of the board P rubbing
on the edges of g g, and therefore the point obtains both a longitudinal and a transverse guide, which
were stated to be essential.
The board c, with a circular edge, and m, with a moulding, would respectively produce circular and
moulded pieces, which would be straight in point of length in virtue of gg the line of motion, and curved
in width in virtue of c or m the lines of the tools. But now c and m must always advance parallel with
their starting positions, or the width of the moulding would vary and this is true, whenever curved
guides or curved tools are employed, as the angular relation of the tool must be then constantly main-
tained, which it is supposed to be by the external piece or guide attached to m.
I
1027.
I
9
g
a
Supposing g g each to have circular edges, as represented by the dotted arc a a, or to be curved into
any arbitrary moulding, the same boards p, i, c, m would produce results of the former transverse
sections, but the clay would in each case present, longitudinally, the curved figure of the curved longi-
tudinal boards a a; here also the line of the tool and the line of the motion would obtain in the result.
If, to carry out the supposition, we conceive the board a a to be continued until it produced the entire
circle, we should obtain a cylinder at one single sweep, if the wire 1 were carried round at right angles
to a a. But to produce the same result with the point p, it must be done either by sweeping it round to
make circular furrows very near together, or by traversing the point from side to side, to make a multi-
tude of contiguous lines parallel with the axis of the cylinder. In either case we should apply the point
to every part of the surface of the cylinder, which is the object to be obtained, as we copy the circle
of a a (which is supposed to be complete) and the line l, or the transverse motion of p, which is
equivalent to a line.
But it is obvious that, in every case referred to, there is the choice of moving either the clay or the
tool, without variation in the effect. If in respect to the circular guide a a, we set the clay to rotate
upon its centre, we should produce all the results without the necessity for the guide-boards a a, as the
axis being fixed, and the tool also fixed, the distance from the circumference to the centre would be
everywhere alike, and we should obtain the condition of the circle by motion alone, instead of by the
guide; and such, in effect, is turning.
An every-day example of this identical supposition is seen in the potter's wheel; and the potter also,
instead of always describing the lines of his works with his hands, as in sketching, occasionally resorts
to curved boards or templets, as for making the mouldings for the base of a column, or any other circular
ornament. But here, as also in ordinary turning, we have choice either to employ a figured tool, or to
impress on a pointed tool a path identical with the one section; for example, the sphere is turned either
by a semicircular tool applied parallel with the axis, or else by sweeping a narrow or pointed tool
around the sphere in the same semicircular path.
Having shown that in every case the superficies is a copy of the tool and of the one motion, or of the
point and the two motions, it will be easily conceived that the numerous superficies and solids, emana-
ting from the diagonal, spiral, oval, cycloid, epicycloid, and other acknowledged lines, which are mostly
themselves the compositions of right lines and of circles, may be often mechanically produced in three
different ways.
First, by the employment of tools figured to the various shapes, and used with only one motion or
traverse; secondly, by the use of figured guides, cams, or shaper-plates, by which the motion is con-
strained, just the same as p makes a right or a curved line, in virtue of its straight or curved guide;
and thirdly, by the employment of a point actuated by two motions, by the composition of which most
geometric lines are expressed.
Thus when uniform motions are employed, two rectilinear motions produce a diagonal to themselves;
one circular and one continued right-line motion, give the spiral, the screw, and the cycloid also if, dur-
ing one circular revolution, either the circle or the point make one oscillation in a right line, we obtain
the oval by two circular movements we obtain the epicycloid, by three motions the compound or dou-
ble epicycloid, and 80 on. And when one or both of the rectilinear or circular generating motions are
variable as to velocity, we obtain many different kinds of curves, as the parabola, hyperbola, and others;
an 1 thence the solids, arising from the revolutions of some of these curves upon an axis.
We produce the practical composition of any two lines or movements, whether regular or irregular,
by impressing these movements on the opposite extremities of an inflexible line or rod from which rod
we obtain a compounded line if we trace the motion of a point inserted in any part of the rod, and we
obtain a compounded superficies if we copy the motion of the entire line. This may need explanation.
Supposing that in Fig. 1027, the back guide gg to remain a straight line, the front to become the
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circular arc a a, the board p being now traversed in contact both with the straight and curved edges,
the point p would describe a line if it were close against the line gg, or an arc if close against the arc
a a; midway it would describe an arc of about half the original curvature. On the other hand, the
line b would cut off the clay in a superficies, possessing at the three parts these same conditions, and
merging gradually from the right line to the arc a a.
But a similar composition of the two lines or motions would occur, were the lines g g, a a to be ex-
changed for any others, similar or dissimilar, parallel or oblique, or irregular in two directions; and in
mechanical practice we combine, in like manner, two motions to produce a compound line or a com-
pound superficies. Indeed in many cases there is no alternative but to impart to two edges g a of a
block the marginal outlines of the superficies, and then, generally by hand-labor, to reduce all the inter-
mediate portions under the guidance of a straight edge applied at short intervals upon the two edges,
which thus become compounded or melted together in the superficies. Numbers of irregular surfaces
can be produced by this mode alone.
In fine, in mechanical processes, we translate the mathematical conceptions of the rectilinear, circular,
and mixed motions of points and lines, into the mechanical realities of rectilinear, circular, and mixed
motions of pointed or linear tools.
It is not imperative, however, that the tools should have but one fixed point or edge, as without
change of principle a succession of similar points may be arranged in a circle, to constitute a revolving
cutter, which by its motions will continually present a new point, and multiply the rapidity of the effect.
In most cases, the introduction of a tool with a figured outline, cancels the necessity for the means
otherwise required to generate such figured line by the motion of a point; and a tool with a figured
superficies, cancels also the remaining motion required to produce the superficies, and the tool is .imply
impressed as a stamp or die.
In tracing the method of applying these theoretical views to the explanation of the general employ-
ment of cutting tools, or the practice of the workshop, we may safely abandon all apprehension of com-
plexity, notwithstanding the almost boundless variety of the elements of machinery, and other works of
cutting tools. For although all the regular figures and solids referred to are in reality met with, besides
a still greater number of others of an irregular or arbitrary character, still by far the greater majority
of pieces resolve themselves into very few and simple parts, namely, solids with plane superficies, such
as prisms, pyramids, and wedges, and solids with circular superficies, such as cylinders, cones, and spheres.
These are frequently, as it were, strung together in groups, either in their entire or dissected states; but
as they are only wrought one surface at a time, the whole inquiry may be considered to resolve itself
into the production of superficies.
The guide principle is to be traced in most of our tools. In the joiner's plane it exists in the form of
the stock or sole of the plane, which commonly possesses the same superficies as it is desired to pro-
duce. For instance, the carpenter's plane used for flat surfaces is itself flat, both in length and width,
and therefore furnishes a double guide. The flat file is somewhat under the same circumstances, but
as it cuts at every part of its surface, from thousands of points being grouped together, it is more
treacherous than the plane as regards the surface from which it derives its guidance, and from this and
other reasons it is far more difficult to manage than the carpenter's plane.
In many other cases the cutting instrument and the guide are entirely detached; this is strictly the
case in ordinary turning, in which the circular guide is given by the revolution of the lathe mandrel
which carries the work, the surface of which becomes the copy of the tool, or of the motion impressed
upon the tool, either by the hand of the workman under the guidance of his eye alone, or by appropri-
ate mechanism.
When the lathe is employed under the most advantageous circumstances to produce the various
geometrical solids or figures, the tool is placed under the guidance of a ruler, or rather of a slide, by
which its path is strictly limited to a rectilinear motion. Thus, for a cylinder the slide is placed exactly
parallel with the rotary axis of the mandrel, and for a plain flat surface the tool is moved on a slide at
right angles to the axis. Generally two slides fixed in these positions are attached to the lathe to carry
and guide the tool, the machine being known as the sliding-rest; but mostly the one slide only is used
as a traversing or directional slide for guiding the tool, the other as an adjusting or position slide for
regulating the penetration of the tool into the work.
Sometimes the two slides are moved simultaneously for the production of cones, but more generally
the one slide is placed oblique and used alone. The lathe is employed with great effect in producing
plane surfaces, but the more modern engine, the planing-machine, the offspring of the slide or traversing
lathe recently adverted to, is now also very much employed for all kinds of rectilinear works.
The planing-machine being intended principally for rectilinear solids of all kinds, its movements are
all rectilinear, and these are in general restricted to three, which are in the same relation to each other
as the sides of a cube; namely. two are horizontal and at right angles to each other, and the third is
vertical, and therefore perpendicular to the other two. The general outline of the machine will be con-
ceived by imagining a horizontal railway to take the place of the revolving axis of the lathe, and the
slide-rest of the lathe to be fixed vertically against the face of a bridge stretching over the railway.
In the general structure of this most invaluable machine, the railway is the cutting slide, upon which
the work is slid to and fro. For producing a horizontal surface, the horizontal slide is employed for
traversing the tool across the face of the work, which is thus reduced by ploughing a series of parallel
grooves, not exceeding in distance the width of the pointed tool, so that first the line, and then the sur-
face arise, exactly as in the geometrical suppositions. For vertical planes, the vertical is the traversing
slide, the horizontal, the adjusting and for oblique planes, the vertical slide is swivelled round to the
assigned angle, the imaginary railway being employed in all cases to give the cutting motion.
When we examine into almost any machine employed in cutting, it will be found that the end to be
obtained is always a superficies, either plane or curved, and which superficies reduced to its elementary
condition, presents length and breadth.
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DEAL SAWING-MACHINE.
When therefore we have put on one side the mechanism required for connecting and disconnecting
the engine with the prime mover, whether animal, steam, or other power, it will be found that when
the superficies is produced by a pointed tool, the primary motions resolve themselves into two, which
may be considered representative of length and breadth. The velocity of the one primary motion is
suited to the speed proper for cutting the material with the most productive effect, which for the metals
is sometimes as low as ten or twenty feet per minute, measured at the tool, and for the woods the speed
is above ten or twenty times as great.
The principal limit of velocity in cutting machines, appears to be the greatest speed the tool will
safely endure, without becoming so heated by the friction of separating the fibres as to lose its temper
or proper degree of hardness.
The cohesion of iron being very considerable, a velocity materially exceeding ten to twenty feet per
minute would soften and discolor the tool, whereas in general the tools for iron are left nearly or quite
hard. Brass, having much less cohesion than iron, allows a greater velocity to be used lead and tin
admit of still more speed; and the fibrous cohesion of the soft woods is so small, that when the angles
of the tools are favorable, there is hardly a limit to the velocity which may be used. Water, soap and
water, oil, milk, and other fluids, are in many cases employed, and especially with the more fibrous
metals, for the purpose of lubricating the cutting edges of the tools to keep down the temperature, the
fluids reduce the friction of separating the fibres and cool both the tool and work, thereby allowing an
increase of velocity and at the same time they lessen the deterioration of the instrument, which
when blunted excites far more friction, and is likewise more exposed to being softened, than when keen
and in perfect working order. There are, however, various objections to the constant use of lubricating
fluids with cutting tools.
The velocity of the other prinfary motion is generally very small, and often intermittent; and it be-
comes a mere creep or traverse motion, by which the pointed tool is gradually moved in the second
direction of the superficies under formation.
In producing circular bodies, one of these primary motions becomes circulating or rotary, and in com-
plex or irregular forms an additional movement, making in all three, or sometimes four, are compounded;
and lastly, when linear or figured tools are employed, one of the motions is generally expunged.
CYLINDER See DETAILS OF ENGINES.
CYLINDER COVER. See DETAILS OF ENGINES.
DAGUERREAN TYPE See PHOTOGRAPHY.
DEAL SAWING-MACHINE, by J. Macdowall. This machine differs from the common saw-mill
frame in having the motive power included in it, and consequently also in the arrangement of several
of its working parts.
By this arrangement each sawing-frame is converted into a separate engine, perfectly distinct from
the adjoining sawing-frames, and capable of being worked or stopped at the pleasure of the attendant,
without affecting any other of the frames contiguous to it. This allows also of any frame being driven
faster or slower than the others, as the qualities or natures of the various kinds of timber under opera-
tion may require.
The machinery may also be constructed without the steam cylinder and piston, and driven by an
ordinary stationary steam-engine, there being a fast and loose pulley mounted upon the main shaft, upon
which a belt from the actuating part of the stationary engine may be passed.
Fig. 1028 shows a front elevation of the machine, looking to the face of the saws.
Fig. 1029 is a side elevation, taken at the left of Fig. 1028.
Fig. 1030 is a section, taken vertically through Fig. 1029.
In all the figures the same letters of reference are used to denote the same parts.
A A. the standards or main upright framings of the machine are bolted to the foundation, and
otherwise firmly secured in their places by flanges: they are also bolted to the main beams that sup-
port the flooring B B, thus dividing the machinery between the upper and lower apartments; the one
of which contains the engine or driving power, while the other is occupied by the saw-frame machinery
strictly so called.
The cylinder of the steam-engine, by the agency of which the sawing machinery is driven, is shown
at C: it is supplied with steam in the usual manner, through slide-valves contained in the valve-casing
a, which receives the steam from the boiler through the main steam-pipe D and the induction pipe E.
Having served its purpose in the cylinder, the steam is discharged by the eduction pipe F into the
waste-steam pipe G.
H H, the main driving-shaft is mounted upon bearings fixed upon the top of the standards A A.
This shaft carries two fly-wheels II, two eccentrics J K, and also the two crank plants LL In these
last are fixed the crank-pins b b, which are connected by the rods to the shaft carrying the frame of
saws dd. This frame travels in the parallel slides or guide pieces e e attached to the cheeks of the
framing A A. It will be seen that while the eccentric J is working the slide-valves, which admit and
discharge the steam to and from the cylinder C, that the eccentric K is imparting motion to the spur-
wheels ff, for the purpose of feeding or leading forward the timber by means of the link or rod g and
ratchet or click h, which drives the ratchet-wheel i and pinion these being keyed upon the same
carrying-stud.
These spur-wheels ff, which are of rather a fine pitch, give a slight progressive motion to the timber
under operation, by means of the system of meter-wheels and shafts III; and it will be perceived that
of those wheels the four lower pairs are so mounted as to communicate their motion to the shaft carry-
ing the intended iron feeding-rollers kk, which, by this arrangement of the geering, all receive an equal
progressive motion simultaneously, and thus feed-in the timber shown at TT.
By these means, the timber in its progress through the machine is gradually advanced and
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DEAL SAWING-MACHINE.
337
presented to the teeth of the saws, as they are driven up and down by the reciprocating action of the
piston-rod 1.
It will also be understood that the extent of progressive motion given to the feeding-rollers through
the agency of the system of geering, just described, may be varied and adjusted by the click or ratchet
h being caused in its receding movements to escape over a greater or less number of teeth of the
ratchet-wheel i, and thus produce a quicker or slower advance of the timber according to the nature of
its grain, or the number of saws which are acting upon it.
1028.
1029.
L
K
I
H
3
B
8
A
c
m
F
E
B
B
B
B
c
G
D
M
j
d
I
7
u
и
N
W
W
A
SCALE.-10 feet=3 inches.
The governor, by which the supply of steam to the valve-box is regulated, is placed at the top of
the machine, and is of the ordinary construction; the working parts of the governor being attached to
the circular plate or disk of metal n, which is driven by the friction of the periphery of the revolving
collar o keyed upon the main shaft. This mode of driving the governor simply by friction is preferred,
because it admits of ready adjustment by sliding the collar nearer to, or farther from, the centre of the
plate n, thereby regulating the speed of the governor, as may be desired by the attendant, whenever
it is necessary to vary the speed of the engine to suit the different qualities of the timber to be operated
upon.
48
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338
DEAL SAWING-MACHINE.
Having now described the general construction of the sawing-frame, it remains to show the mode of
putting it into operation. Let it be understood that the engine for communicating the power is upon
the high-pressure principle, and that the engine shown in the drawings is supposed to represent one of
that construction of about seven horse power,
which will be generally found sufficient for
1030.
ordinary timber. Let it also be observed
that this engine is shown in the position of
half-stroke.
The engine being first started in the or-
dinary way, by opening the throttle-valve
which is placed in the induction pipe E, and
thus admitting the steam, its expansive
force will cause the piston 1 to rise, and by
the crosshead m and side links m' m', will
draw up the shaft M, carrying the frame
L
of saws dd, and thus, through the connect-
ing-rods c c, will drive the crank-plates LL
round, and thereby communicate rotary mo-
tion to the main shaft H, which will impart
I
its impetus to the fly-wheels II, and, at the
same time, cause the eccentrics J K to re-
volve; the eccentric J giving a reciprocating
motion to the slide-valves through the rod
p, the links r, and shaft q; and thus, as the
piston works up and down in the cylinder
in the ordinary manner, it will clearly be
5
perceived that the necessary reciprocating
E
a
F
action will be given to the frames containing
the system of saws dd. These saws are of
course adjustable in their respective frames
so that any number may be employed, and
B
B
also set at any required distance apart.
It has been before stated that the engine
being in operation, the other eccentric K
will meanwhile cause the timber to ad-
A
vance to the teeth of the saws as required,
D
G
by the system of geering which works the
four indented feeding-rollers kkkk. It
will also be perceived by reference to
Fig. 1028, that each of the vertical shafts j
has a feather or raised key upon its surface,
in order to carry the two wheels j'j' round
with them, and at the same time to allow
these wheels to slide upon their respective
shafts while in motion, in case of any in-
equalities upon the surface of the timber
k
d
K
causing the upper feeding-rollers k k to
rise or fall. To keep the wheels in geer
the boss of the pair of horizontal wheels is
T
elongated, and has a groove turned upon it
in order to embrace the end of the shaft
*
of the feeding-rollers, as shown in Fig. 1028.
N
@
Ordinary feeding tables with delivering
rollers are placed in front and behind the
sawing-frame, to conduct the deals and
e
timber to be cut on to the plates N N, upon
W
W
which they are supported while under the
A
operation of cutting; and upon this plate,
at the feeding end or front of the machine,
there is placed a central guide-piece, or fence
SCALE.-10 feet=3 inches.
S, against which the deals are to be pressed by the springs tt, having friction-rollers at their ends for
that purpose. These springs are adjusted to the tightness of the pinch required by the small winch and
screw 26. The tables placed behind the machines to receive the timber after it has been cut into boards
are, in other respects, similar to the front tables. It will be seen that there are two weights W W,
suspended from the shafts of the upper pair of feeding-rollers kk by the rods vv, in order to keep them
down upon the top edge of the timber with sufficient pressure to resist the upward lift of the saws when
cutting. These weights are also suspended in the centre by a small chain and pulley from the shaft w,
and at one end of this shaft is a ratchet-wheel x, the boss of which has mortises cut in it for the purpose
of receiving a small crow-bar, in order to lift the weight and ease the top rollers when required.
DENSITY. See FORCE.
DENSITY. See PHORONOMY.
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DERRICK.
339
1031.
V
o
Top lik.
N2
E
a
Boom 67 67.6
caty
PEX
SCALE.- 16 feet=1 inch.
5
Oil
Whole lengthet mast 69 fest.
0
8ft
Guy
162
own
Platfor Bx15ft
DERRICK, Stone Laying. Used at the United States Dry Dock, Brooklyn. Savage's Derrick:
improved by W. J. McAlpine, Engineer.
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340
DERRICK.
1032.
Mast so
SCALE.-6 feet=1 inch.
DERRICK, plan of a small. Used for setting small stone on the United States Dry Dock, Brooklyn.
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DISTILLATION.
341
DISTILLATION. Improved Stills used in the distillation of rum-By pursuing the mode of manu-
facturing sugar recommended, extremely little molasses will accrue; and the same also applies in re-
gard to the skimmings; consequently there will be no more of the latter, than will suffice to give a
desirable tone to the former: hence it is evident that the operations in the distil-house will be reduced
to a very small scale.
This, indeed, is as it should be every thing is converted into sugar that can be; and it is only the
remnant that ought to find its way into the distil-house for conversion into rum.
Cleanliness is particularly required in every department, from the mill-house to the rum-store: it is
of as much importance in the distil-house as in the milling, boiling, and curing departments; and the
planter who aims at perfect success in distillation, must be nice and clean even to a fault. Every vessel
should be constantly washed and scrubbed, and also well limed down to prevent acidity and by these
means the distil-house, and every thing that is in it, should always be perfectly sweet and clean.
1033.
=
de
R
NO
A
The apparatus used in separating the alcohol from the wash, is generally called a still ; bu. well
descriptions of stills have 80 multiplied of late years, that some 300 or 400 patents might be mentioned,
if it were of any utility doing 80.
The first, which is one of the earliest improved stills, is that invented by Corty, and afterwards much
simplified by Messrs. Shears & Sons.
Fig. 1033 is a representation of this still A being the body of the still into which the wash is put;
B is the still-head; CCC are three plates of copper, fitted into the upper part of the boxes D DD,
which are kept at a regulated temperature by water being conducted over their outer surface, by means
of the pipe E and the distributing-pipes G G G. The spirit-vapor then, rising from the body of the still,
meets a check at the lowest plate C, by reason of the coolness occasioned by the water; this condenses
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342
DISTILLATION.
the grosser part of the vapor and throws it back, whilst the lighter proceeds on to the second plate C,
where a further coolness condenses another portion of the vapor, leaving a much purer spirit to encoun-
ter the increased coolness at the third plate C. Here the last separation takes place; the aqueous and
oleaginous particles being unable to sustain the temperature maintained, fall back condensed, and only
a very strong spirit passes over in the gooseneck. By means of the cock F, in the pipe E, the supply
of water to the boxes D can be very exactly regulated; and, as a natural consequence, the temperature
can be very accurately adjusted. If the temperature of the upper box be kept at 174°, for example,
the alcoholic vapor which passes over will be comprised of 90 per cent. of pure alcohol, or 65 over
proof; but with a temperature of 194° Fahr. the vapor will contain only 66 per cent. pure alcohol, or
30 per cent. over proof. a is a screw-cap, through which a jet of steam or water may be sent to clear
away the deposite, which otherwise will more or less accumulate on the upper surfaces of the plates C.
At the lower end of the worm-pipe is affixed, by means of the brass swivel-joint screw H, a gas ap-
paratus. The peculiar form of the pipe I into which the spirit runs from the worm, causes it to be
filled shortly after the still commences working; whilst the other branch pipe K rises to some height,
then returns, and is immersed in the small box L to the extent of about two inches in water. The gas
from the still escapes by this pipe through the water, as the pressure can be but trifling.
It is held, that by means of this gas apparatus the distillation proceeds in a partial vacuum, and that
thereby there is a great economy in fuel. As the spirit enters the worm at 80 much lower a tempera-
ture than in the old stills, that quantity of water is not required to cool the spirit vapor as would be
otherwise.
A still of 400 gallons is said to work off four to five charges in the day of twelve hours; yielding a
spirit on an average of 35 per cent. over proof: which, for rum, is considered the most advantageous
strength to run it at.
Fig. 1034 is another arrangement of the same kind of still; being the addition of the common still A
to the patent still B. In this case the contents of B are drawn down from time to time into A, and that
of A run off as dunder; the spirit from A being conducted into B. One fire heats both stills; and it is
stated that by the general adaptation and arrangement, a very large quantity of fine spirit is produced
by the consumption of a very inconsiderable amount of fuel.
L
1034.
c
M
B
H
b
a
A
I
I
a
I
The stills of Blumenthal, Laugier, and Coffey, though very excellent, and no doubt very efficient, are,
notwithstanding, much better adapted for European distilleries than for sugar estates. I have seen
many of them, as well as modifications of them, working on estates in India and the Straits; but I
never knew them to afford satisfaction to their possessors: probably from not having such careful and
skilful workmen to intrust them with, as are obtainable in Europe. From what I have already said, it
will be seen that I entertain a very good opinion of the stills represented in Figs. 1033 and 1034, and
consider them well adapted to the requirements of a sugar estate. But of all the different arrange-
ments, I have never known any to surpass the common still and double retorts.
As a distilling apparatus peculiarly suited by its simplicity, durability, economy, and efficiency, to
the wants of the planter, I consider that it stands unrivalled.
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DIVING-BELL.
343
Fig. 1085 represents the appara-
tus as it is commonly used; but, if
1035.
provided with a wash-heater, the
pipe from the second retort, instead
of passing directly to the worm-
tank, would first run through the
charger containing the wash, impart
to it a large portion of its heat, and
then enter the worm-tank. A still
of 1,000 gallons, so provided, should
run off 500 gallons of rum, avera-
ging 30 to 40 per cent. over proof,
between five o'clock in the morning
and eight o'clock P.M. In working
the apparatus, the still itself is load-
ed with wash, and the two retorts with a few gallons of low-wines, or even water, sufficient to cover
the bottom of the vapor-pipe : say about 15 or 20 gallons of low-wines in each.
The fire is then applied under the still, and rum of 40 to 45 over proof commences to flow into the
can placed ready to receive it. When the still begins to boil, the loud rumbling of the retorts gives in-
timation of the fact, and warns the attendant distillermen to prepare for the spirit in the can-pit.
I
M
J
1036.
D
D
E
c
M
J
c
E
R
I
R
G
Q
B
B
M
D
N
T.I.
H
0
DIVING-BELL This diving-bell was invented and patented by Dr. J. Rutherford Worster, of Bal-
timore, Maryland. This diving bell need not be made very heavy-it can be lowered perfectly steady
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344
DOCKING SHIPS.
in the most rapid currents-the water does not rise above an inch or two within, when immersed. It
can sit perfectly steady on the most uneven bottom, as it does not depend on that to sustain it. It is
lighted with artificial light, and is abundantly provided with fresh air. The invention consists of a per-
pendicular stationary scaffold, erected on a scow, or between two, and a sliding frame to which the bell
is attached below, which runs in grooves in the side of the scaffold, operated by rack and pinion, to
apply an unlimited power to force the bell steadily downwards into the water, and raise it in the
same manner.
Fig. 1036 is a front elevation; Fig. 1037 is a vertical section of the bell showing its interior and
Fig. 1038 is a top view, looking down upon the frame and scaffold. The same letters indicate like parts.
A A are the floats; BB, transverse beams of the scaffold; and DD are uprights of the moveable frame,
made secure by diagonal braces EE The uprights D D move in guide grooves formed by two or four
upright posts connected by ties. On the edges of DD are racks, indicated in front by F. G are pinions
on the scaffold, which are operated by cranks, and by biting into the racks elevate and lower the bell
and moveable platform. RR are two diagonal braces of the scaffold. II are tubes to "carry off the
smoke from the lamps HH. These lamps have oil reservoirs SS, which regulate the supply by two
1037.
1038.
D
I
M
J
I
IN
a
a
H
H
a
0
P
cocks, and the air to the lamp can be regulated by another cock below. J is the speaking tube with
a mouthpiece L. M is the air-tube; and T, the air-pump. These tubes are made of metal above the
bell, but connected with the flexible tubes K N inside. o is the bell-platform. VV, the water line.
This apparatus is all made in sections, and can be taken to pieces and packed in a very small compass.
DIVISION OF FORCES. See PHORONOMY.
DOCKING SHIPS, Apparatus for. The slip, Figs. 1039 to 1042, consists of three timber-ways, one
central and two lateral, laid down on piles or on the firm beach, and running into deep water. These ways
carry a rail, on which work the trucks or rollers of the carriage or frame DD. This carriage or frame
consists of three strong longitudinal trucks, secured together by six, seven, or more moveable cross-pieces,
the carriage being hauled upon the ways by means of a wheel and pinion, capstan, or other purchase.
On the keel-beam D of the carriage, blocks are laid to such a height that the keel of the vessel may
clear the ends of the cross-pieces, and each block carries four rollers. On the cross-pieces, on each side,
are laid sliding or chock-blocks F F, which are made to suit the rising of the ship's bottom, and are
worked backwards and forwards on the cross-pieces by tackle. They are also secured on the cross-
pieces by a rack and pawl. On the aftermost cross-pieces are also two shores II, which turn upon a
joint, and are prevented from falling outwards, when the vessel is floating on, by means of a small
chain.
A vessel having floated on to the slip, the sliding-blocks are adjusted by the tackle under her keel,
the tackle being taken on board the ship, and hauled tight. By this means the sliding-blocks are
brought into the proper place, and the pawls fall into the racks on the cross-pieces, and wedge the vessel
firmly in. The iron guides at her forefoot and at her stern are also hauled up, so that she is well
secured to the carriage. Of course, the carriage being inclined, the vessel takes first the foremost
blocks, but the others are gradually adjusted, and as the carriage is hauled up the slip, the vessel takes
the remaining slide-blocks in succession. When duly prepared, the vessel and carriage are hauled up
the slip at the rate of from 21 to 5 feet per minute. The power employed is in about the proportion of
six men to every hundred tons.
When hauled up, the vessel is shored from the ground, and the keel-beam being relieved from the
weight can be run back so as to be used again. It should be observed, that during the hauling up the
carriage is prevented from falling back by means of three or more pawls at different parts of the
framing, working on the rack on the midway.
The launching of a vessel from the slip takes place very easily, by putting the cross-pieces and chock-
blocks under her and the keel-beam.
This slip admits of more than one vessel being on the slip at the same time, as the carriage or cradle
is moveable, and the vessel, when ashore, can be shored up in the usual way.
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DOCKING SHIPS.
345
The expense of this slip, exclusive of the cost of preparing the foundation and laying down, expenses
varying of course according to locality, is stated thus :-
For vessels of 100 tons
$2178
"
"
200
"
2904
"
"
800
"
3872
"
"
400
"
4840
"
"
500
"
5324
And for vessels of greater burden in proportion.
In case of voyages of discovery, or expeditions to distant countries, a slip for hauling up the ship
might be carried out in framing as cargo, and erected at any convenient place.
It has been objected to this slip, that the side blocks or wedges being drawn under her bottom upon
the cross timbers can have no other support than those timbers; and should only one, two, or three of
them along midships have taken the weight, and yielded however little, the inclining pressure of the
ship at the same time must be augmented by the leverage of all that part thereof overhanging the side
blocks, which are thus converted into fulcra, and the superincumbent weight to an active force. The
danger that the cross-timbers will break down, or the ship break in, and thus fall over, becomes immi-
nent, and an accident of this nature did actually happen.
1041.
1042.
k
K
X
&
*****
1039.
b
1040.
E
N
E
D.4
0
E
N
ID
B
m
The American Marine Railway, as it is commonly called, or the Railway Dock, as it is styled in the
patent, was brought forward about twenty years ago.
The marine railway laid down at New York is said to have cost between 70,000 and 80,000 dollars;
and to be only capable of taking one ship at a time. The charge for docking is 25 cents per ton.
The plan of proceeding is thus described by Mr. J. L Sullivan, C. E:-
"The process of constructing the railway dock requires, first, the regulation of the bottom, if 80 shoal
as to interfere with the intended slope of the work; or it may be excavated within the shore with the
proper slope, if a channel should prevent its extension.
'The foundation piles are to be driven in four lines; the two inner rows near to each other, in order
to support the keel the two outer rows to come under the shores.
" The distance between the piles will be determined by the size of the timbers which bear the iron
rails.
"The size of the timber will depend on the burden of the largest ship which it is contemplated to
haul up. Four feet apart in the centre line will be generally sufficient; in the side lines eight feet.
44 The piles to be cut off under water must be cut off in the exact inclination of the plane, and level
44
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346
DOCKING SHIPS.
with each other transversely. The necessity of previously marking each pile separately, on every
side, in accordance with the intended inclination of the ways, led to the invention of instruments re-
quisite to the occasion.
" An aerial inclined plane parallel to that intended to be established under water is obtained by first
fixing a true level across the head of the railway, and denoting each station by a target, the staff of
which is so much above the line of plane as will bring the lower end of the aerial plane above water
targets, having each a staff of the same length, being next applied, and nailed to the outer, and some
few to the intermediate piles, will exactly indicate the aerial inclined plane, while the point of the
staff attached to the pile will indicate a point on one side thereof in the intended plane of the
foundation.
The level and bevel is an instrument by which to ascertain every other point on the sides of the pile
which will be in the intended inclined plane. Fig. 1043.
"The diving-bell may now be supposed to be brought over the pile, and as much of this as it will take
in cut off, together with the target staff, still leaving the lower end. This cutting is repeated till the
workmen arrive in the bell to the bottom of the staff, which remains a little below the last rough
cutting. The level and bevel is then set on: this consists of a base-board, with a post arising from its
centre to support a plumb-line playing in a cant piece having a centre notch, to determine whether the
base is level transversely and as this base is at the same angle with its post that the intended plane is
to a perpendicular line, and the base being equally thick, its under side also indicates a parallel plane,
80 that, being secured in its place, the distance is measured by compasses from the ascertained point to
the base-board, and thence to every point in the circumference of the pile that is also in the intended
plane, thus marking it with accuracy for cutting. This operation being the same for each pile, it results
that every one must be truly in the intended inclined plane, ready to receive the frames of the railway,
which are floated over, and sunk down to their places; or a plank is first secured upon the head of the
piles, upon which the frames are successively slid down.
The iron rails will, in point of size, depend upon the weight they are to bear. They must of course
spread a sufficient base to prevent being indented into the wood by a heavy load. The two middle
rails, and the rack piece for the pawls, are generally cast in one; but if the rails are to be of rolled iron,
the rack will be separate. The pawls prevent the ship from accidentally running back.
"The pressure of the load will, in merchant ships, be greater forward and aft than at midships,
because they generally become a little hogged; provision must therefore be made for this contingency,
and it will be safe to suppose cases in which the largest class of ships to be received will bear all their
weight on the first 10 feet forward and the last 10 feet aft.
"The weight of a ship is often erroneously stated to be as many tons as she measures tons. The fact
is, that when laden she displaces a quantity of water that would precisely weigh her whole weight,
cargo included; and, as she generally carries as many tons as her measurement, she cannot, when
light, weigh as many tons as she measures; she weighs only as much as the water she then displaces,
and that will be in accordance with the weight of her materials, oak, pine, or cedar. Wherefore, for
explanation, I shall suppose the positive weight of ships to be one half of their nominal tonnage.
is A ship of war will be received upon a railway carriage with the precautions to be subsequently
explained, and its weight distributed equally over it and the foundation. The tendency of all ships
being to acquire some curvature of keel, it will generally be injudicious to straighten them on the dock,
as they will resume their lines on being again put afloat, opening thereby the upper seams or butts. To
keep the ship, when taken out of the water, in precisely the same shape she has in it, the curve of the
keel must be ascertained, and the keel-blocks be made to conform thereto.
" To measure the curvature of the keel we have devised an instrument, consisting simply of a bar,
suspended at each end by a graduated chain. This bar, being long enough to reach across the ship, is
passed under and across her centre at every five or ten feet, when the graduations on the chains will
show the difference of depth at every point of contact from stem to stern. For merchantmen this
precaution will not generally be necessary.
A ship of 500 tons measurement will exert a pressure of 250 tons, and we have supposed the whole
of this may have to be borne by the two extremities of the carriage, or by 10 feet at each end. The
axles, therefore, are at the extremities, but nearest to each other. But as steamboats will bear heaviest
in the middle, the axles must be near in the centre also, for their support.
The axles will be two feet apart in the first 10 feet. Five axles will have to bear 125 tons, or 25
tons each; the bearings and wheels 12} tons. The axles of the New York Dock are 3 inches diameter,
and the square of the section is 7,071 inches. The bearings are close to the wheels in which the axles
are fixed.
" The strength of the rail is deduced from experiments, from which it resulted that a rail of 1
square inch would be ample; but a rail of 1 inch is too narrow to be favorable to the duration of the
wheels.
The central axles of the New York Dock weigh but about 1 ton, and would together suspend
9,300 tons.
The friction of the axles should be relieved by the intervention of brass bearings, as usual in
machinery.
44 The side axles will sometimes have a proportionate share of the ship's weight to sustain; though she
will ordinarily be prevented from inclining on one side or the other by the adjusting-screw placed at the
angles of the shear-shores; yet it is necessary to guard against the force of high winds, and the weight
which a hogged ship may sometimes throw on the centre shores, before she is eased down at midships
by the screws, if intended to be straightened. (Fig. 1045 i.)
" The carriage is combined in a very strong manner, though it appears to be rather a light structure
for the purpose. In its construction the implement called the dowelling-bit is of great and essential use.
(See Fig. 1048.)
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DOCKING SHIPS.
347
" The dowell is a cylinder of some hard wood, generally lignum-vitæ, which is one half inserted into
one, the other half into the other timber, where a joint is to be made of their surfaces, which the dowell
prevents from moving or sliding on each other. The gouge and the screw, perceived on reference to
Fig. 1055, are also improvements. An auger hole, a little smaller than the screw of the bit, being first
bored, the thread will cause the bit to advance as fast as the chisel and gouge can conveniently cut,
and thus the whole labor is confined to turning it.
" The instrument now makes it easy to dowell the frames of a ship, the knees to the timbers, the
waterways to the beams, the thick stuff of the wales to each other, and generally to bind the ship by a
solid connection of wood.
1043.
A.
1044.
1046.
1045.
c
9
1047.
h
1
b
1048.
a
m
m
d
d
1050.
1049.
coll
1051.
1053.
1058.
3
h
1057.
1052.
I
a
c
1054.
1056.
1055.
1059.
" By means of irons and the dowell, the cross-ties are secured to the sills in such a manner as to make
it impossible that the carriage should spread; and by thus tying the sides to the centre, the cross-tim-
bers convert the oblique force of the shores into vertical pressure; and care is taken in every instance
that a wheel shall stand directly under the base of every shore.
"The shear-shores (Fig. 1045) have a form which gives them great stability in their places, and an-
swers other purposes to be mentioned; they are bases in hollow coin blocks, either of wood or iron,
divided across the middle of the hollow by a partition, which serves to hinge the two legs of contiguous
shears. There is thus a continuity of solid material from the side of the ship to the foundation, from
the moment she ceases to float till she is high and dry.
"The shear-shore screws will sometimes have the important office, when ships are old and tender, of
taking a good share of the weight of the ship's side, and distributing it along the carriage side, taking it
off from the floor timber-heads, futtocks, and beam-ends, where ships are most liable to be weak.
"The bilge levers (Fig. 1045) are levers of the second class. One end is lodged fixedly on the centre
sill of the carriage, while the other end is hove up between the legs of the shear-shores by a windlass
placed within them. The moving end is guided in a slot of the prop, and sustained, when up to contact
with the bilge, by means of an iron pin passing through the cheeks of the prop.
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DOCKING SHIPS.
The cradle thus formed by the bilge levers it is evident will fit every successive vessel equally well,
and may thus be removed singly, and replaced as the work progresses; and as they require to be
hauled up with considerable force, nothing can be desired more convenient than these sheara.
'The common keel-blocks are of course placed between the cross-ties, and are of such height as to
allow ample room for the shipwright to work under the flat of the bottom, standing between and on the
cross-timbers. But the bottoms of the keel will sometimes have to be repaired. To accomplish this
end, the instrument called the lifting-plane has been devised, (Fig. 1046.) In the operation of this ma-
chine, two wedges are forced on by percussion; blows from opposite sides being simultaneously given,
with the combined strength of a considerable number of men, when the resistance renders it requisite.
"The lifting-planes are composed of six pieces of timber, and for the navy may be made of cast-iron,
or of wood faced with iron. To make them, let us suppose a block 4 feet long, and 16 inches square,
halved horizontally, and each face of the cut marked lengthwise, and then shaped into two similar
planes inclined in opposite directions. The two planes are then divided from each other by a bar of
iron, let in edgewise till its edge is flush with the upper ends of the two planes, in order to guide the
wedges. Now let the upper half be placed in its original relation to the under one, (over it,) and there
will be space for two wedges, pointing in opposite directions parallel to each other, separated by the
bar of iron before mentioned. The planes being eight, all at the same angle of inclination, the upper
block, with whatever may be upon it, will be lifted perpendicularly by driving the wedges. These re-
quire heavy blows, and for this purpose battering-rams, swung each between two files of men, are
necessary. (Fig. 1046.)
In practice, one of these machines placed near a keel-block is easily made to take the pressure from
it by the least degree of lifting, and thus several machines may be applied, 80 as even to take away all
the common blocks, and they themselves may be readily withdrawn and shifted in position, 80 as to
allow the bottom of the keel to be got at for coppering, shoeing, or renewing; and when done, the com-
mon blocks are to be replaced. To do this, when'a ship is hove down, her keel must be hove com-
pletely out of water.
'The chain and compound windlass by which the ship is hauled out is an expensive and essential
part of the machine.
The power to draw up a ship of 500 tons, weighing, as before assumed, one half the same number
of tons, is now to be considered. From the experiments made in different places, the weight which
the chain must bear is 40,320 lbs, or 18 tons.
The chain of a marine railway must be, however, exposed to accidental stress beyond this calcula-
tion. It has to ply around a ratchet-wheel, and animal force is often irregular. A steam-engine would
therefore be the best.
"The shape of the chain, in order to give it a degree of strength proportionate to the material, is of
importance, as it has to bear the stress of turning around the ratchet-wheel of the windlass.
" The windlass is also 80 geered as to adapt it to the power of a few horses. When they travel in a
walk the ship moves up the plane about 8 feet a minute, and she is completely up in less than two
hours. Four horses are a sufficient force for a ship of 500 tons. The horses work in the second story
of a small building; they are attached to bars 14 feet in length, proceeding from an upright shaft, on
the lower part of which is a bevel-wheel communicating with the rest of the geer.
The end of the chain is strongly fastened to the centre of the carriage, with branches passing obliquely
to the sides, so that the whole must move equally, and at once.
The reversal of the draught at will is an essential provision, in order to draw the carriage out to the
extremity of the ways, to which its own gravity would not certainly carry it, because to be able to give
the carriage such a position as to afford just water enough for the ship to ground on the upper blocks is
indispensable. To be able to refloat the ship, should she happen by bad management to ground other-
wise than on the centre of the carriage, may, if on a falling tide, be of great consequence; we must
therefore have the readiest means of drawing the carriage down the ways. With this view, the chain,
after passing the haul-up wheel, is led to another ratchet with reversed teeth, and thence down along in
a trunk by the centre timber of the ways till near their extremity; there it turns around a large and
strong shiver, and fastens about 20 feet from the end of the carriage, which the chain follows, when
drawn up, it being supported on rollers. The reversed movement, of course, draws the carriage down
till it touches the stop-block at the outer end of the railway. The chain is thus disposed of without
manual labor. The connection of the second ratchet with the first is by intervening geer, 80 that they
move alike.
The ship in descending requires a controlling power, that she may not acquire momentum, and
injure the carriage by velocity. The friction for this purpose is produced by means of an iron wheel
on the upright shaft, placed just below the floor. An iron band is made to clasp this wheel by the aid
of a powerful lever. This is found to be quite sufficient, and very convenient.
The manner of receiving a ship is this:-she is brought between the wharfs of the dock, head on
the carriage is drawn down under her, and perhaps up a little, till her forefoot grounds on the forward
block, and as ships generally draw more water aft than forward, she is nearly aground aft also; the
head-shores are applied, she is then moored up a few feet, until she is ascertained to touch aft also; the
shores are now all applied and secured, and the bilge levers are hove up to their bearing; she is now
ready to rise into the light and air.
The wheels or sheaves running on the rails are made small, because it is an object to keep the
carriage low, that we may not have to extend the ways further than is necessary to get the desired
depth of water on the carriage.
This structure, it is to be observed, is only accessible for repairs by the diving-bell. In all places
exposed to the worms the timber must be coppered, unless the white gum tree is found to be unassaila-
ble, as some have represented."
At New York there is also a company called the New-York SCREW-DOCK Company, to whom belong
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DOCKING SHIPS.
349
the screw-dock, and the hydro-
static screw-dock, which is an im-
40
proved form of the invention, and
with hydrostatic power brought
to bear as the lifting force.
66
The screw-dock in general
principle and form is the same as
the hydraulic screw-dock. The
vessel in the screw-dock is float-
ed on to a timber platform, which
platform is suspended from strong
mainway pieces of beams on each
side, laid on the quay walls, by
eight suspending screws four and
a half inches in diameter. The
platform is capable of being sunk
about ten feet below the surface
of the water, to receive the ship.
This platform has several shores
on its surface, which were brought
to bear equally on the vessel's
bottom, to prevent her from cant-
ing over on being raised out of
the water. About thirty men
were employed in working this
apparatus, who, by the combined
power of the lever, wheel and
pinion, and screw, succeeded, in
the course of half an hour, in
raising the platform, laden with
a vessel of 200 tons burden, to
the surface of the water, where
she remained high and dry, sus-
pended between the wooden
frames.
In a dock at Baltimore, of this
kind, the platform is suspended
1060.
by forty screws of about five
inches in diameter.
The Hydrostatic Screw-Dock is
a slip abutting on the shore, with
a suspended keel, allowing the
vessel to be raised up vertically,
instead of being drawn up on an
incline, as in the slip and the ma-
rine railway. It consists of two
outer and parallel ranges of piling,
each bearing a way at the top,
from which are suspended chains,
to which are alung transverse
bearers or swing beams, over
which the vessel to be docked
floats; and having arrived over
this moveable platform or grating,
DD
the chains are raised by means of
a hydrostatic press, and the ves-
sel brought to the level of the
permanent way. The means by
which the apparatus is worked
are ingenious, and constitute the
chief merit of the application.
The dimensions of the dock are
about 165 feet long internally,
and 35 feet wide. The distance
from the outside of one mainway
to the outside of the other is 51
feet. The mainways abut on the
land, and run about 38 feet be-
yond the head of the dock on to
the land, resting on a solid quay
of masonry, to which they are
bolted down, and which supports
the machinery.
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350
DOCKING SHIPS.
We shall first describe the construction of the two parallel mainways. These ways (B B, Figs.
1060 to 1069) are placed 35 feet apart, and each consists of a row of double piles A A, with every
pair placed obliquely; thus, A. The piles are of the best Georgia pine, 56 feet long and 20 inches
square, with iron shoes, and with their heads mortised into the mainway pieces, and bolted together
with 14-inch bolts. The divergence of the double piles from the perpendicular is about 3 feet at the
lowest extremity. The piles in the longitudinal direction of the ways are placed 4 feet 8 inches apart.
The depth of water at the site of the dock is 40 feet, needing no excavation; and the piles are driven
into the foundation soil about 84 feet. Some of the piles are further apart than others, depending upon
circumstances and contingencies, but the general distance is about 4 feet 8 inches. The total number of
pairs of piles in each way is about 29, making a total of 116 piles. (Fig. 1060.)
The mainways B B are, as already mentioned, scarfed or mortised on to the top of the double piles,
and secured by iron 14-inch bolts, Figs. 1060, and 1061. Each mainway is 182 feet in length, and is
formed of Georgia pine logs, placed five together A , and bolted together by the same bolts which
secure the heads of the piles. These ways are about 4 feet 10 inches broad and 2 feet 10 inches thick.
Through the mainways, passages are left for the suspending chains. At the end of the mainways are
chocks Z to prevent vessels from slipping off.
On each mainway, again, are mainside straps EE, Fig. 1060, being double, and each composed of
three pieces of Georgia pine, the centre about a foot thick, and the others about 8 inches, making a total
height of 2 feet 4 inches, and a breadth of about a foot. The mainside straps stand about 10 inches
apart, and are secured together by strong bolts and square trenails of locust-wood z The straps are
124 feet in length. The side straps are secured to the cylinder C, by side straps of wrought-iron, 32
feet in length and a foot broad, bolted in, and fastened to the side rods h of the cylinder by a large gib
i, Fig. 1062. On each mainside strap are two ratchet-plates and pawls, hereafter to be described.
At every 6 feet 4 inches in the mainside straps, a wrought-iron cross-bar or distance piece 1 is fixed
in, which is an eye or box u, to receive the head of the suspending chain k. This head consists of a
screw m, secured by a nut, which regulates the height of each swinging beam 80 as to fit the keel of the
vessel. From the screw m a chain k descends, passing between the mainside straps, mainways, and
the spaces between the piles, and terminating in a wrought-iron linkhead and cross-bar o, sustaining
the transverse bearers or swinging beams p. The chains are each about 24 feet long.
Between the two mainways B, Fig. 1061, hangs the platform of swinging beams, suspended by the
chains k, which run over the sheaves n. The mainways are 35 feet apart, and the swinging beams p
44 feet long, consisting each of a double beam about 7 inches apart. The beam is of a flat triangular
form, made up of large logs, fastened together by six iron straps. The pairs of swinging beams are
twenty in number, and each single beam is of oak, about 15 inches broad, 3 feet 3 inches deep in the centre,
and 18 inches at the ends. Each pair of swinging beams is suspended by a chain k at each end. On
the centre of the swinging beam is a keel-block to, 8 feet long, 2 feet broad, and 10 inches deep, to re-
ceive the keel of the vessel. In it are boltheads also to receive blocks-tackle y, for managing the chock-
blocks t. On every second swinging beam is a traverse frame q, raised on six short bearers. On this
traverse frame is a ratchet-plate x, into which a pawl falls from the chock-blocks. On the ratchet-plate
rests the chock-block t, 5 feet 3 inches high, 4 feet 10 inches broad, and 18 inches thick. These chock-
blocks support the sides of the vessel, and are moved backwards and forwards on the swinging beam
by blocks and tackle yz. This tackle it will be seen works both ways, and is also affixed to the pawl x.
On the quay or landside is the engine-house and pump-room, in which is the machinery of a 6-horse
power steam-engine for working the hydrostatic press. In it is a tubular boiler A *, much like a loco-
motive boiler, 15 feet long, 3 feet broad, and 6 feet 3 inches high, with steam-pipe B* communicating
with the horizontal cylinder C and valve-box B*, which lie parallel to the boiler. This piston carries
a connecting rod E*, which sets in motion the mainshaft F at right angles, and in the direction of the
mainways, by which four cranks G* G* are worked, each of which has a pair of pumps attached. Each
pair of pumps has a separate cistern in the tank N*, which, instead of water, is filled with a fluid com-
posed of equal parts of water and alcohol, to prevent freezing in the winter months. These are the
pumps which produce the pressure within the hydrostatic cylinders CC. The diameter of the smaller
pumps is 1 inch, and of the larger pumps 2 inches, and each set of pumps has its respective stop-valves
for letting on and off to the hydrostatic cylinders C C, 80 that one or more may be worked at pleasure.
From the main-shaft power is also obtained for fleeting back the ram, by means of a pinion H set
in geer on the wheel J * by a clutch I*. The wheel J is on a parallel shaft k *, carrying a pinion
K *, from which a bevel-wheel M takes the motion at right angles to another shaft M*, on which are
the two pinions LL, Fig. 1062, which turn the bevel-wheels I of the parallel screws jj of the hydrosta-
tic ram, so that the power is brought to the back of the hydrostatic cylinders.
A hydrostatic cylinder C, Figs. 1060 and 1061, is attached to each mainway, secured, as already
mentioned, by its side rods h through a strong gib i to the mainside rods E. The apparatus consists of
two strong wrought-iron parallel side rods hh, 44 feet long and 6 inches diameter, united by a cross-
head d, 4 feet 8 inches long and 2 feet broad, at the upper end. Within this framing is the cylinder C
and ram D. The cylinder, including the glands, is 18 feet long, 18 inches internal diameter, and 2 feet
3 inches external diameter. On the top of each cylinder, Fig. 1061, are pipes o communicating with
the pump-room. The ram or plunger is 1 foot 2 inches diameter, and made sufficiently long to admit
of a direct motion forward of 15 feet. The outer end is fitted with a collar x into the crosshead d.
The crosshead d, Fig. 1061, travels backwards and forwards by means of rollers e on a cast-iron way f,
laid on the mainways B. At the dock end the mainside rod h is crossed by the fleeting shaft M * from
the engine-room, already mentioned, and the pinions L, on which work the wheels I of screws j, secured
by a box K to each of the side rods h, Fig. 1062. At the extremity the side rod h carries a roller M
and handle N.
We shall now proceed to describe the process of taking a vessel into the dock. The hydrostatic
Digitized by
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1061.
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DOCKING SHIPS.
1064.
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DOCKING SHIPS.
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1066.
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1065.
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352
DOCKING SHIPS.
353
engines are charged with water, and the rams D forced out to the full extent of their stroke. By this
means the mainstraps E are drawn towards the head of the dock, and the cradle of swinging beams
lifted up, 80 as to allow of the adjustment of the keel-blocks w w and chock-blocks t, and of the swinging
beams, by means of the adjusting-screws m, to the suspending chains. The cylinders are then dis-
charged, the rams fleeted back, the pawls loosed, and the cradle of swinging beams sunk again by its
own weight, the mainstraps being checked from running over the mainways by the chocks Z*. It will
be observed that the cradle may be stopped at any required depth by closing the escape-valves, and
by lowering the pawls-bars 8 on the ratchet-frames r.
3
39
1070.
1071.
R
10
*M
The vessel to be repaired is then floated into the dock, brought over the keel-blocks, and the hydro-
static engines and pumps set to work until sufficient pressure is created to raise the swing beams up to
the keel. The motion is then stopped, and the traverse frames q and chock-blocks t hauled in by the
tackle towards the centre of the cradle, so as to take a uniform bearing under the body of the vessel.
When they have done so, the pawls x are let fall on the rack 80 as to fix them in their places, Fig. 1066.
The vessel is now shored up and the engines again started, when by the hydrostatic pressure the rams
are forced in a few minutes out of the cylinders, dragging the mainstraps E, which take the chains
along with them, and the vesscl is raised on the cradle of swing beams, as represented in Fig. 1060,
high and dry above water, so as to allow of the inspection by the shipwrights of every part of her bot-
tom. The cradle is supported on the platform by the pawls and racks 8 r.
45
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354
DOCKING SHIPS.
When the vessel is to be released, pressure is again put upon the cylinders, and then, the escape-
valves being opened, and the pawls and racks sr released, the cradle sinks as the water escapes from
the cylinders; the traverse frames and side chock-blocks are removed, and the vessel allowed to
float out.
The mode of fleeting back the rams, Fig. 1062, is to detach the side rods h, by drawing out the gib ii,
and turning round the roller M, by the handle N, which supports the end of the side rod h. The side
rod having a little play on the crosshead d, allows it to be passed back with ease. The clamps and
boxes KK are then attached to the side rods, and the
screws j turned by means of the bevel-wheel and pinions I
and L, the motion of which is taken from the mainshaft F*
of the pump-room, Fig. 1070, by putting on a clutch I*.
Another dock company at New York, is that called
the Sectional Floating Dock Company. The docks of
this company are the most powerful, being capable of lift-
ing vessels of 2000 tons burden.
This dock is executed at a comparatively small cost,
being chiefly of timber, and being more powerful and
efficient, is esteemed preferable to all the others.
The entire safety of this system is another advantage,
as it is scarcely possible that an accident can arise either
to the vessel raised or to the workmen employed in the
repairs. The dock, also, instead of being fixed, and in one
position, like the marine railway and screw-docks, may
be towed to any vessel within a convenient distance.
Suppose that a ship is sunk, say in 5 fathoms water, it
may be raised to the surface by hogsheads, or slung by
any of the usual modes; and once got up to the surface,
the sectional floating dock can be readily introduced be-
neath it, and the whole towed together to the landing or
shipwright's wharf.
Although this dock has many facilities, it has, however,
some of the inconveniences of dry-docks, as the vessel is
hidden between the towering sides and the machine sheds
on them; and the whole forms a damp structure of
wood.
1072.
The sectional floating-dock derives its name from its
consisting of distinct sections of timber framing in the
form of a floating-dock, into which ships can enter. In the
sections on each side are balance-tanks, raised and lowered
by means of a rack and pinion, and also tanks, which, by
being filled with water, cause the dock to sink, and by
na
,the water being pumped out, enable it to be raised to
any required height out of the water, the ship resting on
the platform within. On the top of the sections is ma-
chinery for working the racks and pinions and pump-
work.
x
B
Such is the general principle of the contrivance. Now
to detail the construction. According to the size of the vessel
to be raised, any number of sections, more or less, may be
used, as convenience suggests. Each section is 92 feet
broad externally, and 64 feet internally, and 23 feet long
the total length of the seven sections being 165 feet. The
section is 38 feet high externally, exclusive of engine-
house, and 28 feet high internally to the top of the stand-
ards. The dock, it will be seen, is neither more nor less
than a large floating timber vessel, and is constructed of
beams strongly bolted together.
Each section may be considered as consisting of three
parts-two lateral scaffoldings or framings of standards
within which the balance-tanks run, and a central plat-
form connecting them. The object of the lateral framing
is to enable the balance-tanks B to be run up and down,
and to prevent the machines from coming in contact with
the water. Each lateral portion consists of two external
standards 36 feet high and 12 inches square, and of four internal standards 37} feet high and 12 inches
square. These standards are at the bottom secured to the outside truss-girders, and on their tops
carry a platform on which the engine apparatus is placed. The standards are bound together by
proper tie-pieces, and are further secured to the outside truss-girders by a 12-inch beam, 44 feet long.
At the bottom of each lateral framing is a flooring on which rests a balance-tank B, 191 feet long, 10
feet broad, and 8 feet deep, being of a capacity of about 1,500 cubic feet. The total capacities of the
fourteen tanks would therefore be 21,000 cubic feet. Besides these are water tanks within the plat-
form in which the pump-rods work.
The platform is about 10 feet deep, and on the upper surface consists of two outside truas-girders
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DOCKING SHIPS.
355
being about 70 feet long and 17 inches across, composed of two beams scarped together. Between these
are a cross-beam, 7 inches square in the centre. secured to the keel-beam; and a cross-beam on each
side 9 inches square, for carrying the chock-blocks, and secured to the keel-beams. These cross-
beams rest on joists or tie-pieces 10 inches square. In the centre across are the two keel-beams,
241 feet long and 12 inches square, and which carry five keel-blocks. This upper platform rests on
the foundation truss-girders, by means of posts and timbers scarfed in. and is further secured by four
stout iron ties. The bottom truss-girder is 93 feet long, and formed in three portions, well scarped,
tied, and bolted together. These bottom truss-girders extend under the lateral framings, knitting to-
gether the whole structure.
The sections are connected together, in case of need, by the double tie-beams, which can be readily
slipped out, by withdrawing the nuts and screws by which they are secured.
On the cross-beams on each side is a rack and pawl, enabling the chock-blocks to be readily
moved, and secured by means of tackle. The chock-blocks are 4 feet high and 3 feet 9 inches wide.
These receive the bottom of the ship; but in order to steady the sides there are side supports on each
side, worked by block and pawl. so as to make the ship firm to the inner standards.
The object of the balance-tanks is to keep the dock steady and in an upright position. They con-
tain no water, and it is only necessary to keep them depressed to the level of the water, either in
sinking or raising the dock, and their resistance keeps the whole dock, with the ship, perfectly steady.
The lateral framings are
furnished with two station-
ary spuds 34 feet high and
7 inches square, provided,
on one side, for 273 feet,
Shut
1073.
with a rack-plate. This
spud is secured into the
framing at top and bottom,
I
and is for the purpose of
working the tank up and
down by machinery. subse.
quently to be explained, and
part of which is seated on
1074.
the top of the tank B. Each
D
lateral framing is also pro-
C
vided with a ladder, and an
J
1
upper stage for the work-
men.
On each side of the centre
section is an engine-house,
which contains the machi-
nery for working the thrust-
Open
1075.
ing and pumping apparatus,
and from which shafts run
along the sections on each
D
side. It should be observed
that the machinery on all
the sections is covered in.
The engine-house contains a tub da. boder like a locomotive boiler, with steam-pipe and exhaust
pipe, cylinder and valve-box. From the piston a crosshead carries a connecting-rod working on the
crank, which drives the main-shaft, on which is the balance-wheel. From the main-shaft a pinion and
bevel-wheel carry the motion to the shaft, which is the longitudinal driving-shaft, continued, as here-
after explained, along the sections for a length of 140 feet. From this longitudinal driving-shaft a
wheel, working by a belt on the wheel, communicates the power to the pumping geer on the shaft,
crank, and pump-rod, running down the water-tanks. This geering can be thrown in and out by means
of the moveable pulley, which by being raised or let fall tightens or loosens the belt. The longitudinal
shaft also works the shaft, by which the thrusting-geer is moved, and which, by means of the wheels
and pinions, put on or off by the clutch, works the tank and pinion either upwards or downwards as
may be required. The shaft is connected at each end by means of the universal joint, and by the
small circular shaft, with the longitudinal shafting on the end sections. By this means the different sec-
tions may be placed at such distance from each other as the length of any ship may render necessary.
It is to be observed, that a necessity constantly occurs for sinking one or more sections lower than the
others. This is also provided for by the slip and universal joints.
The thrusting-geer for raising and lowering the tank takes its motion, as mentioned, from the shaft,
by means of the bevel-wheel, which moves the pinion, the head of the square vertical shaft. On this
shaft is a moveable socket, with a square hole in it, and four friction rollers, so that the vertical shaft
may easily pass through it. Beneath the friction rollers is a pinion working into the bevel-wheel.
This bevel-wheel is on the horizontal shaft, secured into a framing on the top of the platform of
the tank. The horizontal shaft carries a worm, working into the worm-wheel, the shaft of which car-
ries a pinion at each end, working into the spud, which is kept in geer by the friction roller. The
number of spuds is twenty-eight, four on each section, or two for each tank. On the end sections the
machinery consists merely of the longitudinal shaft, the thrusting and pumping geer.
The process of taking a ship into the sectional floating-dock is as flollows:-The dock is sunk to any
required depth by opening the gates or valves with which each water-tank is furnished, and the dock
recessarily sinks. The dock sill being at the required depth, the ship is then introduced between the
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356
DOCKING SHIPS.
vertical side-framing, rests on the keel blocks, and when supported on the sides by the chock-blocks and
side-supports is ready for lifting.
The valves which have previously admitted the water into the water-tanks are now closed, the water
is pumped out, and the air again fills the tanks, and they rise, bringing with them the vessel to the
height necessary for repairs.
The vessel is taken out of dock by a repetition of the process of admitting water into the tanks.
The patent is for the general arrangement in the construction of the side-balance tanks.
Besides these several kinds of dock apparatus in actual working at New York, many plans have been
proposed in the United States, and nearly fifty patents taken out within the last twenty years, for the
invention and improvement of slips,
marine railways, floating, and other
docks.
In 1826, Captain Thomas Cald-
well proposed a system of dock
D
1076.
D
without pumping power. He pro-
posed to construct a dry-dock of
T
T
about twice the usual length; to
be divided into two compartments
T
V
c
I'
by gates situated near the centre of
the structure; an additional pair of
gates being placed at the extremi-
$
s
ty, opening a communication with
the harbor. The vessel was to en-
B
B
k
c
0
ter the first compartment, the ex-
K
ternal gates being closed, and the
A
internal gates being opened. The
bottom of the second compartment
1077.
would be above the level of the
D
D
water in the first or outer compart-
ment, and consequently at this pe-
riod dry. The water was then to
S
be permitted to flow from an ele-
vated reservoir, through a pipe,
A
H
into the dock. When by this
means the surface was sufficiently
a
elevated, the vessel was to be
D
D
hauled into the second compart-
ment, constructed in all respects
similar to a common dry-dock.
The central gates being closed and
secured, the water was to be dis-
B
charged into the adjacent harbor,
Fig. 1073.
In 1826, Commodore Barron, of
the United States Navy, invented
a floating dock in the form of a large scow. (See Fig. 1076.) It will be seen that it is a large flat-
bottomed boat, furnished at one end with a pair of gates, and having on each side two air-tight trunks
TT, to preserve the buoyancy of the dock when filled with water. In the sides are port-holes, like
those of a man-of-war, 80 as to allow of being opened when the dock is above water, and admitting
light and air, and the introduction of materials. In case of being used in salt-water, it was proposed to
copper the outside of the dock as high as the float-line of the dock when it contained no water. As
the dock would not be exposed to much friction, the Commodore was of opinion that very thin sheets
of copper might be used.
When the gates are open the dock fills with water, and sinks to a depth sufficient to allow vessels to
enter therein, and of course to displace their weight of water from the dock, when the gates are closed
and secured. The vessel is then shored, and secured by the shores N and S in the usual way. The
water is next to be removed from the docks by common pumps, the Archimedean screw, or by a pump
forcing the water out through the bottom, which latter plan was preferred.
Letters D DD, Fig. 1077, represent the floating dock containing the vessel S. HA is the surface of
the water in the harbor, which would coincide with the surface of the dock, supposing it to be sunk to
the dotted line, which is its situation when full of water. This depth is also supposed to be 20 feet, or
equal to A B. At the commencement of the operation of pumping the water from the floating dock, it
resembles the common dock, in not requiring any power to exhaust it; but as the pumping proceeds
the dock becomes lighter, and of course the bottom does not remain in the same relative position to the
surface of the water in the harbor, but rises in proportion to its buoyancy.
In the figure the dock is represented as having risen. It is now immersed to the depth of about 5
feet. It is not necessary to remove the water from the space occupied by the ballasting, shaded dark
in the lower part of the figure. As the water is forced out through an aperture in the bottom, the
greatest resistance to be overcome is equal only to the pressure of a column of water equal in height to
the line A B, (5 feet ;) half of this, or A x = 21 feet, will be the average resistance during the whole
operation. Therefore, the power required to remove the water from the floating dock by a forcing-
pump, will be to the power required to remove the water from a common dry-dock on the usual plan,
as, 21 : 10, or as 1 : 4; viz. as A x Fig. 1077 = to 2f feet is to A x dry-dock = 10 feet. If, however,
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DOCKING SHIPS.
357
lifting or forcing pumps be employed to pump the water up, and discharge it over the sides, then, of
course, the same power will be required for Barron's dock as for the fixed dock.
Commodore Barron's dock was proposed to be moored in a slip between two wharves or breakwaters,
to flank and protect it from injury, and with a raft or floating breakwater moored in front of the dock-
gate, to preserve it from storms.
Literal References.
The Patent Slip.
1. The bilge lever.
Fig. 1039. Elevation of the slip.
m. The prop for supporting the bilge lever.
1040. Ground plan of the slip.
Fig. 1046. Side view of the bilge levers and shear-
shores.
1041. Section on sea side.
1042. Section on land side,
Figs. 1047 to 1053. The lifting-planes, shown in
detail.
A. Ground line.
B. Sidewise, laid on piles, C C.
a. The ship's keel.
C. Midway, with rack a and pawl b.
b. The upper block of the lifting-planes.
DDD. Carriage cradle, or frame of timber.
c. The under block of the lifting-planes.
D*. Keel beam.
dd. The wedges.
EE Cross-pieces of timber, with rack and pawl.
e f. The block in different points of view.
The cross-pieces are moveable.
Fig. 1054. The battering-rams.
FF. Sliding or chock-blocks, working on the rack
gg. The battering-rama
of the cross-pieces EE, and provided with a
Fig. 1055. The improved dowelling-bit.
a. The chisel, as in the old implement.
rope m.
G G. Oast-iron rollers, running on a rail on the ways
b. The cutter, as in the old implement.
BBC.
c. The gouge, improved.
h. Block hooking on to carriage DD.
d. The screw, improved.
i. Chain attached to block, and working on
Fig. 1056. The New York chain.
H. Capstan-wheel and pinion, or other purchase,
Figs. 1056 and 1057. The under-water implements
and works.
firmly bedded on a large stone.
aaaa Piles.
IL Shores.
jj. Iron guides turning upon a pivot, and made by
b. Pile standing out of water.
means of the tackle k to fit under the ship's
C C. Piles cut off to the line of the plane.
stern.
d. Pile in the process of cutting off in the diving-
k k. Ropes for hauling up guides or crutches.
bell, Fig. 1058.
11. Iron guides and oblique braces for the forefoot
6. The level and bevel in the diving-bell.
of the vessel
f. The batten and target.
KK. Vessel on the slip.
g g. The aerial plane, parallel to the intended
m m. Ropes of the sliding-blocks, which are taken
plane.
h. The water-line.
on board the ship for the purpose of being
hauled in.
i. Compasses.
k. The ground-line.
1. The intended plane.
The Marine Railway, New York.
Fig. 1059. Tucker's improved chain.
Fig. 1043. Elevation of railway, with vessel on the
slip.
Elevation of Platform of Hydrostatic Dry Dock
A A. Piles.
without the Hydraulic Engines.
a. Windlass loft.
A A. Piles in pairs, 56 feet long and 20 inches
b. Hauling-up geer.
square, of best Georgia pine, shod with iron,
c. Chain attached to the carriage.
placed 4 feet 8 inches apart, supporting the
C. Vessel supported by the shear-shores on the
cradle.
carriage.
BB. Mainway pieces, shown in detail in Fig. 1066.
dd Shear-shores.
C. Cylinder of the hydrostatic engine.
Fig. 1044. End view of railway.
D. Ram or plunger-pole working in C, and attached
AA. Piles.
at the outer ends to
aaa Midway and sidewise.
d. Crossheads, shown in detail in Fig. 1062.
366. Cast-iron sheaves or trucks, flanged, and run-
6. Friction rollers supporting d, and travelling on f.
ning on cast-iron rails.
f. Cast-iron way on which the crossheads d run.
c c. Timber framing or sill of the carriage.
E. Mainstraps of wood constituting the moving or
dd Cross-piece of timber.
draught-frame from which the cradle is suspended,
e e. Bilge levers.
(shown in detail in Fig. 1068.)
ff. Shear-shores.
h. Mainside-rods from the crossheads d to the main-
g g. Scaffold posts.
straps E, (shown in detail, Fig. 1063.)-
Fig. 1045. View of the bilge levers and shear-
ii. The gib securing the mainside-rods h, and main-
shores.
straps E, (shown in detail, Fig. 1068.)
a The ways.
J. Wrought-iron straps bolted along the main-
b. The rail.
straps E.
c c. The cast-iron sheaves or trucks.
k k. The suspending chains.
dd The sill of the framing.
n n. Cast-iron rollers for carrying the suspending-
e. The plank.
chains k to the cradle pp.
f. The cross-tie or piece.
00. Wrought-iron linkheads and crossbars, support-
g g. The hollow coin-blocks or side-blocks.
ing the transverse bearers pp.
h. The shear-shore.
pp. The swinging-beams or transverse bearers of
i. The screw.
the cradle, (shown in detail in Fig. 1069.)
k. The windlass.
r r. Ratchet-plates on the mainstraps E.
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DOCKING SHIPS.
88. Wrought-iron pawl-bars, (shown in detail in Fig.
A A. Piles.
1067.)
BB. Mainway piece.
2*. End chock of timber to prevent the vessel from
EE Mainside straps.
slipping riverwards.
kk. The suspending chain to the transverse bear-
A steamer is shown in the dock.
ers pp.
1. Iron crossbar or distance-piece, in which eyes are
Fig. 1061.-Plan of the Hydrostatic Dry D ock,
formed to receive the adjusting-screw and nut
New York.
m of the suspending-chain k.
BB. Mainway pieces.
m. Wrought-iron adjusting nut and screw.
C C. Cylinders of the hydrostatic engine.
98. Cast-iron sheave for carrying the chain.
D. Ram of ditto.
o. Wrought-iron linkhead and crossbar supporting
d. Crossheads to which the ram D is attached.
the transverse bearers or swinging-beams p
e. Friction rollers supporting d and travelling on f.
pp. Transverse bearers or swinging-beams of the
f. Cast-iron way on which the crossheads d run.
cradle.
EE. Mainstraps of wood from which the cradle is
rr. Ratchet plate on the mainside strap E.
suspended.
88. Wrought-iron pawl-bar.
h. Mainside-rods from d to E.
16. Box in the crosshead, at the back of which is the
ii. Gib securing the mainside-rods h h, and the
nut m.
mainstraps EE
Fig. 1066. Enlarged plan of mainside strap E and
J J. Wrought-iron straps on E.
pawl-bar 8.
k. The suspending chains to the transverse bearers
Fig. 1067. Enlarged section of mainside strap E,
pawl-bar 8, mainway piece B, and piles A.
11. Wrought-iron crossbars or distance-pieces be-
A A. Pair of piles, each 56 feet long and 20 inches
tween the timbers of the mainstraps E, and in
square, of best Georgia pine, with iron shoes,
which eyes are formed to receive the adjusting-
diverging from the perpendicular, at the lowest
screws and nuts m of each suspending-chain k.
extremity, about 3 feet.
m m. Adjusting-screws and nuts of the suspending-
a* a*. 14-inch bolts to secure piles.
chains k k.
B. Mainway pieces of five logs of Georgia pine,
n n. Cast-iron sheaves or rollers for carrying the
182 feet in length by 2 feet 10 inches in thick-
suspending-chains k k.
ness and 4 feet 10 inches in breadth, with piles
pp. The swinging-frames or transverse bearers of
A A mortised in.
the cradle carried by the suspending-chains k k.
E E. Mainside straps, constructed of three pieces
qq. The traverse-frames.
of Georgia pine.
rr. Ratchet-plates on the mainstraps E, on which
r. Ratchet-plate or rack on the mainside strap.
the pawl-bars 8 work.
8. Wrought-iron pawl-bar.
88. Wrought-iron pawl-bara.
x*. Trenails of locust wood.
0*. Pipes communicating with the pump-room.
Fig. 1068. Elevation of swinging-beams or trans
to 10. Keel blocks of timber.
verse bearers pp.
xx. Iron rack and pawl for keeping the chock-blocks
k k. Suspension-chains of iron.
in their places.
pp. Swinging-beam or transverse bearer of oak,
y*. Balks bearing the trasverse-frames q.
strapped together by the wrought-iron straps v.
2*. End chock of timber.
qq. The traverse-beams of timber for supporting
the chock-blocks t.
Hydrostatic Dry Dock.
t t. Chock-blocks of timber for supporting the sides
of the vessel.
Fig. 1062. Enlarged plan of hydrostatic cylinder,
v v. Wrought-iron straps.
with the fleeting apparatus.
w 10. Keel-block of timber.
C. Hydrostatic cylinder 18 feet long.
x x. Iron rack and pawl for keeping the chock
D. Ram secured to the crosshead d by the collar
blocks in their place.
x*.
yy. z 2. Blocks and tackle for working the chock
d. Crosshead.
blocks.
E. Mainstraps.
Fig. 1069. Plan of the swinging-beams p.
h h. Mainside-rods.
i. The gib securing the mainstraps E and mainside
Fig. 1072.-Hydrostatic Dry Dock. Front Eleva
rods h
tion of the Pump-Room.
jj. Screws for fleeting back the ram D.
A*. Tubular boiler.
KK. Clamp and box attached to the side-rods hh
IL Bevel-wheel working on the pinion L
B*. Steam-pipe.
LL Pinion to the wheel I.
C*. Cylinder.
D*. Valve-box.
M*. Shaft from the engine-room turning the pin-
ions L
E*. Connecting-rod from cylinder C* to shaft F*.
MM. Roller moved by the handle N.
F* F*. Mainshaft working the geering.
N. Handle supporting the end of the mainside-
G* G*. Cranks from shaft k* to the pump-rods
rod h.
each crank working two pairs of pumps.
H*. Pinion on shaft F*.
x*. Collar connecting the ram D and crosshead d.
Fig. 1063.-Elevation of the mainside-rod h, with
I*. Clutch for putting pinion H* in geer with
wheel J*.
the roller M, and handle N.
Fig. 1064-Cross section through the cylinder, side-
J*. Wheel on shaft k*, for transferring motion to
rods, and mainways.
the geering for fleeting back the ram.
k*. Shaft bearing the wheel J* and pinion K*.
Hydrostatic Dry Dock.
K*. Pinion on shaft k* working with the wheel
L*.
Fig. 1065. Enlarged longitudinal section of one of
L*. Wheel for transferring the power at right angles
the mainside straps E
to the shaft M*.
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DRAWING MACHINE.
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M*. Shaft turning the pinions LL
F*. Main shaft.
N*. Tank. P*. Balance-wheel.
G*. Crank for working the pump-rods.
p*. Pump-rods.
Hydrostatic Dry Dock.
Fig. 1070. Plan of the pump-room.
Barron's Floating Dock.
A*. Tubular boiler. B*. Steam-pipe.
Fig. 1076. Barron's floating dock. DD. Dock.
C*. Cylinder. D*. Valve-box.
kk. Knees at the angles bolted firmly to the hori-
E*. Connecting-rod. F* F*. Main shaft.
zontal or upright timber DD.
G* G*. Cranks working the pump-rods p* p*
ccc. Horizontal or inclined slips of ceiling, running
H*. Pinion on shaft F*.
fore and aft, into which the timbers DD are in-
I*. Clutch for putting fleeting apparatus in geer.
serted.
J*. Wheel on shaft k* for transferring motion.
TTT. Air-tight trunks. V. Vessel in dock.
k*. Shaft bearing the wheel J* and pinion K*.
SS. Waleshore supporting the ship V.
K*. Pinion. L*. Wheel on shaft M*.
hh. Horizontal shores. BB. Keel-blocks.
M*. Shaft turning the pinions LL
Fig. 1077. Barron's floating dock raised out of the
LL Pinions working in geer with the wheels IL
water.
IL Wheels on the spindles of the screws jj.
ij. Screws for fleeting back the ram D of the hy-
Caldwell's proposed Dry Dock.
drostatic cylinder.
Figs. 1073, 1074, and 1075. The dock, with vessel
N*. Tank. 0*. Chimney-flue.
entering, floating, and lying. A. Reservoir.
P*. Balance-wheel 10 feet diameter.
B. Pipe communicating with the inner-dock C.
0*. Pipes communicating between the tank and
C. Inner-dock. D. Inner-gate. E. Vessel.
the hydrostatic cylinder CC; each set of pumps
F. Outer-gate. G. Outer-dock. H. Ground level.
provided with separate stop-cocks.
I. Level of the water in the harbor.
Fig. 1071. Side elevation of the pumping apparatus.
J. Level of the water in the dock.
DOCK. See FLOATING SECTIONAL
DRAWING MACHINE-Lowell Machine-Shop.
Fig. 1106 is a front elevation, with
c
cans A removed.
Fig. 1107 is an end elevation, show-
1107.
ing geered end of rolls.
x
Fig. 1108 is an end elevation, show-
ing pulley end of rolls.
o
A is the tin cans into which the
slivre is deposited.
3
T
B is cast-iron end, or support for
frame.
C is the plungers or crowders that
press the alivre into the tin cans A A,
after it has passed through the rolls.
I
Des
D is an upright shaft for driving-
cam b¹, and giving a rotary motion to
R
the cans AA.
B
5"
E is a stand attached to r for sup-
port to upright shaft D.
c
a
E' is a pair of calender-rolls, rest-
ing upon the table D₁, by means of
A
stands J, through which the slivre
passes before entering the tin cans.
G is a bushing or bearing-in floor,
to guide lower end of upright shaft to
I
plungers.
G' G' and W are weights for
weighting top rolls.
1.1
D' is a table of iron, sometimes of
wood, to support calender-rolls.
A
ZZZZ are steel rolls fluted there
are three and four, and sometimes five
rolls, which increase in velocity from
the first to last sets, making the
draft.
S' are stands to support rolls ZZ,
dc.
B
B
A' is a stand to support the end of
driving-roll.
XX are stands to hold belt ship-
ping-bar, which is wood, sliding in the
stands.
X', bevel-geers on cam-shaft.
A
b¹, cam for producing up and down
motion on the crowders CC.
o
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DRAWING MACHINE.
1106.
X
Y
A
GI
4
H
F
и
?
D
b/
e
X
K/
d
fl
N
DI
B/
A/
EA
N
H
Y2
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DREDGING, AND DREDGING-MACHINES
361
V
A
c
X
0
W
X
V
1108.
no
3
E
1
z
1010
B
K' is a mangle-wheel, which gives an alternate circular motion to the cams A, which are driven by я
pulley and shaft fl, which has a pinion on the lower end geering into the mangle-wheel. The pulley
fl is driven by a belt from the upright D. i is a friction-roll attached to a lever g, which raises and
falls the crowders ccc. Y, Fig. 1106, represents the edge view of roll-geers. 00, wooden clearers.
which are covered with cloth for clearing top rolls from waste cotton. P are driving-pulleys, tight and
loose. Q, geers on back roll. S is an arm operated by a stop-motion RT, which moves arm W. that
is attached to shipper-bar in stands XX. T is a light tin trumpet, over which the slivre passes in en-
tering the rolls. In case the slivre breaks or runs out, this trumpet falls back, which throws out a ratch,
and lets the slide, by means of a spiral spring, press against arm S, which works arm W, and stops the
machine. The roll-geers are made to vary in size to suit the operator on No. of yarn which may be
required.
DREDGING, AND DREDGING-MACHINES. The dredging-machine, since the application of
steam-power, has sufficiently proved, in many parts of the world, the most efficient expedient towards
the advancement of commerce and commercial interests, not only as the means by which accumulated
obstructions have been removed, but also as the means by which rivers have been enlarged to a suffi-
cient extent for the transit of commodities by navigable means; but to enumerate all of even the most
conspicuous of those places that have thus been benefited, would much exceed our limits, and not
materially, as regards the present purpose, add to any important advantage;-however as reference may
be required by individuals for further information, a few places shall be named at which dredging-ma-
chines have been, and are now, advantageously employed.
In the North River, New York, dredging-machines have been and continue to be extensively em-
ployed, and the merits of the great improvements in that river are entirely due to their successful
operations. At the time when the value of steam, as a moving-power, began to be appreciated by
parties interested in navigation, many rivers could offer but small inducement to enterprising speculators,
on account of their extremely contracted breadths, and the want of sufficient depth of water to admit
vessels with an advantageous cargo.
Dredging forms a very important part of the work of the civil engineer, and is effected in various
ways; either by drags or scoops, or rakes, or machines. There are two sorts of hand-drags, one for
raising mud, the other sand the first consists of an iron box pierced with holes, open in front as well
as at the top to this is attached a slightly flexible handle, of a length proportionate to the depth it is
to work in when this is made use of, the men in a boat make the iron box enter the sand, sustaining
the handle on the shoulder, and when it is filled they raise it, and if there be any large stones they are
disengaged by means of hooks a man will raise in this manner, where the depth is not more than 4 or
5 feet, a cubic yard in the course of a day, and sometimes more.
The Drag for Mud is differently formed it is an iron ring, to which a canvas bag is attached, by
passing a cord through holes made in the ring purposely to receive it that point of the iron rim
which is intended to touch the ground and enter the mud must be sufficiently strong two men in a
boat or punt are required to manœuvre it, and in the course of a day they will raise from 12 to 14
cubic yards, if the depth does not exceed 6 feet when the boat is made use of, it is first moored in
such a manner that it cannot drift such a drag allows the water to flow out of it, and retains only the
solid matter.
The Louchette, a kind of spade, or a collection of them, is used for cutting or extracting turf under
water, without the necessity of first pumping it dry : this consists of a light iron frame, which is armed
all round with a cutting-blade, in length about 3 feet; the part between it and the handle is open,
being formed of four horizontal rods, and two vertical ones these receive the turf after it is cut and
detached, and enable the workmen, by means of a rope and windlass, to pull it up; these cutting instru-
ments have a variety of forms given them to adapt them to the peculiar work they may have to perform.
The Box Shovel consists of an open box fixed at the end of a long handle, usually made of iron; the cutter
traverses in a groove, and is worked by another handle; by this the turf is cut and detached, and each
successive piece falls into the box: as many as four turfs may be thus drawn up at one time.
46
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DREDGING, AND DREDGING-MACHINES.
Dredging-machines have been constructed in various ways, and of iron or wood, according to the
nature of the service. Some machines have been arranged 80 that the system of chain and buckets
should work through a channel in the middle of the vessel; others with one system on each side; and
others with the buckets working over the extremity of the vessel. But, in general, the modern practice
is to place the machinery towards one extremity of the vessel, to allow of the working of the ladder
(which holds the buckets) freely on either side of the vessel. By this arrangement barges can be laid
along both sides of the vessel, and the material raised by the machine be taken away more easily. The
machinery consists of upright and horizontal shafts, on which bevel-wheels, together with the reels or
barrels, are fixed for working the chain and buckets, which latter, by being pointed with steel, dig into
the soil, which is raised to the upper reels, whence it falls down an inclined board or shoot into the
barges. These reels or barrels are made to disconnect by means of friction-clutches, 80 that either or
both sets of buckets may be stopped at pleasure, or in case of any obstacle, such as an anchor or a stone
intervening, the friction-clutch allows the reels to slip, and thus prevents the machine from breaking.
The ladder containing the chains and buckets can be raised or lowered to suit any required depth, and
the feeding of the buckets can be regulated by means of a windlass, which is worked by the engine.
1078
The buckets, which are now made with boiler-plates, hold from five to six cwt. of material.
The dredging-machine has been employed very advantageously in raising mud, sand, gravel, and
even chalk, from different harbors and rivers, both at home and abroad.
A good dredging-machine ought to raise from a depth of 25 feet, from 150 to 200 tons of gravel per
hour when properly worked, or a ten-horse power will raise from 90 to 100 tons per hour about thirty-
four feet in height, or 700 to 800 tons per day, being at the rate of 10 tons of materials per horse power
per hour.
Description of the 25-horse power Engine and Dredging machinery constructed by Bury, Curtis, and
Kennedy, Liverpool, for deepening the Bay of Santander, in Spain-The Figs. 1080 to 1083 represent
an elevation, plan, and sections of the boat and machinery.
The engine A is a side-lever low-pressure condensing marine-engine of 25-horse power, having a cylin-
der 28 inches diameter, and 3 feet stroke, (crank making twenty-eight revolutions per minute:) the
cylinder is fitted with short D-valves of brass.
The air-pump B is 18 inches diameter, lined with brass 5-16ths of an inch thick, with a brass bucket,
brass discharging and foot valves; rod of wrought-iron, cased with brass.
The engine is fixed on a cast-iron bed-plate C, 11, inches thick, secured to the keelsons of vessel by
sixteen 14-inch bolts; the condenser D is cast solid on the bed-plate.
The side-levers EE are 9 feet 34 inches long, 19 inches broad in the middle, and 11 inches thick in
the plate; the main centres are keyed into the condenser on each side.
There are two fly-wheels FF on the crank-shaft, each 13 feet 6 inches diameter, rim 9 inches deep
by 5 inches broad on the edge. The crank-shafts are made of cast-iron, 7 inches diameter in the jour-
nals, and supported at the ends by brackets fixed to the side of the boat.
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DREDGING, AND DREDGING-MACHINES.
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The engine is provided with a governor G, which is driven from the crank-shaft by a belt and pulleys.
The framing H, columns, and crank-pedestals are cast in one piece.
The boiler 1 is 11 feet long, 8 feet wide, and 6 feet high, with steam-chest 5 feet long, 4 feet 6 inches
wide, and 1 foot 8 inches high.
Dredging-machinery.-The spur-wheel J on the fly-wheel shaft, which connects the engine and other
wheels for working the machine, is 4 feet 6 inches diameter to the pitch line, 24 inches pitch, and 8
inches broad on the edge, which wheel works into another wheel K, 9 feet 4 inches diameter, 21 inches
pitch, and 8 inches broad on the edge; and on the shaft of this last-mentioned wheel there is fixed a
wheel L, of 4 feet 5,1 inches diameter, 31, 1-16th inches pitch, and 10 inches broad on the edge, which
works into a wheel M keyed on the bucket-shaft, 8 feet diameter, 31 1-16th inches pitch, and 10 inches
broad on the edge.
1079.
a
SCALE.-1 inch=10 feet.
n
The main or bucket shaft N, on which the 8-feet wheel is keyed, is of cast-iron as far as the coupling-
boxes on each side; the ends of this shaft rest on pins 3 inches diameter, fixed into the tumbler-shafts
00, which are made of wrought-iron, and turned to receive the tumblers PP. The shaft for lower
tumblers QQ is also of wrought-iron, and works in chilled cast-iron bushes.
The upper tumblers PP are square, with hoops of wrought-iron 4 inches by 11 inches, (steeled on
the corners ;) the flange on one end is made loose for the purpose of putting the hoops on. The lower
tumblers QQ are square also; the part under the bucket-link is chilled. There are four steel knives in
each flange for the purpose of cutting the soil before the bucket.
The hangers RRRR for carrying the bucket-frames are of cast-iron, the inner one firmly bolted to
the side-framing; the outer one is fixed on the end of the transverse beam S.
The bucket-frames or ladders TT are 48 feet long between the centre of the upper and centre of the
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DREDGING, AND DREDGING-MACHINES
1080.
-3 SCALE-3 inches=25 feet.
I
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1081.
?
SCALE.-3 inches=95 feet.
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DREDGING, AND DREDGING-MACHINES.
lower tumblers; they are made of the best English oak, each side in two pieces 12 inches by 6 inches,
and bolted to the cast-iron brackets at each end with 11 inch bolts.
The buckets U are made of boiler-plate I inch thick, and welded at the corners. Each bucket has a
steeled mouthpiece riveted to the bucket.
The bucket-links V are of wrought-iron, with a ring of steel 11 inch thick, welded into the eye of each
link; they are 221 inches long between centre and centre. The pins in the joints are also steeled and
case-hardened.
The rollers W on the bucket-frame for carrying the buckets are 9 inches diameter.
The coupling-boxes X on the bucket-shaft are for the purpose of disengaging the tumbling-shaft
when only one row of buckets is required to work. These coupling-boxes are also fitted with a friction-
strap to prevent accidents to the machinery if the buckets should meet with any obstruction.
The mitre-wheel Y on the bucket-shaft, 2 feet 31 inches diameter, works into a mitre-wheel a, keyed
on the end of the upright shaft Z, and on the lower end of this shaft there is another mitre-wheel b,
1082.
S
SCALE.-8 feet=1 inch.
S
R
T
which works into a mitre-wheel c, keyed on the chain-barrel shaft. The barrels for hoisting the end of
bucket-frames are of cast-iron, with a brake-wheel fixed on the end for lowering the frame when the
barrel is disconnected from the intermediate shaft by the coupling-box; the handles of the coupling-box,
and also the brake-handle, are placed on deck.
The lower end of bucket-frame is suspended by a f-inch chain, and two three-sheaved blocks; the
lower block is connected to the bucket-frame by a bow of wrought-iron.
The rope geering for hauling the boat forward receives motion from the upright shaft Z in the follow-
ing manner. A mitre-wheel d, 1 foot 10 inches diameter, is fixed on the upright shaft, working into
another mitre-wheel e on the intermediate shaft; and on this shaft there is a spur pinion f, 111 inches
diameter, which works into a wheel g, 3 feet diameter, on the capstan-head shaft. The capstan heads
h are of cast-iron, fixed on each end of shaft; on the middle of this shaft is fixed a fuzee pulley.
The slack-rope barrels ii are of cast-iron, with a coupling-box and friction-wheel, the handles of which
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are placed on deck: there is a pulley j, 2 feet diameter, on this shaft which is driven by a belt from the
fuzee pulley before mentioned.
The construction of dredging-machines is both necessarily and optionally of various designs.
Necessarily, because machines with two sets of buckets, or buckets on each side of the vessel, are not at
all adapted to narrow rivers, on account of their unavoidable breadth and consequent obstruction and
optionally, because the arrangement of the machinery is at the entire discretionary judgment of the
constructor. Hence, two different modifications of most approved machines are annexed; the one by
Messrs. Summers, Groves, and Day, of Southampton, and the other by Messrs. Girdwood and Co., of Glas-
gow; and although they differ materially in design, are each equally efficient in their proper situations.
a
S
N
N
1083.
SCALE.-8 feet=1 inch.
S
M
R
The best adapted boilers and engines for dredging purposes, are those upon the marine principle, as
in them compactness and stability are combined; and for which reasons, they of that description are
invariably applied; but in practice it is found disadvantageous to the profitable working of the machine,
if the engine be not of a proportionate power to the depth of water, the buckets of a suitable number,
and the bucket-frame of sufficient length to lie at a proper angle. Hence, the following arranged pro-
portions are annexed as the best adapted for working at or about the various specified depths from
which the material is to be raised :-
Nominal Power
Length of
Number of
Depth of Water
of Engine.
Bucket-Frame.
Buckets.
in feet.
20
591
34
18
25
68
36
20
30
781
45
25
The boat requires little or no peculiarity of form, otherwise than that of proper stability ; it must
be strong and well put together, or a constant tremulous motion is created by the action of the
machinery, and the proper effect of the machine in a measure destroyed. It must also be of magnitude
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DREDGING, AND DREDGING-MACHINES.
sufficient for the receiving of the machinery with a proper clearance for the buckets, according to the
depth of water, and different positions in which, on that account, they are 80 frequently required.
That portion of the construction in which is required the greatest degree of attention, is the judicious
selection and application of proper materials ; also, in the proper proportional exactitude of the parts of
which the machinery is composed.
Description of the Machinery in the Dredging Vessel constructed by Summers, Groves, and Day.-
The objects which were chiefly kept in view in arranging the machinery of this dredging-engine, were
simplicity of construction with efficiency and facility in adapting it to the work it would have to
perform: and after some consideration, it appeared to the makers that a marine steam-engine, with side-
beams, was the best kind of engine for this purpose, as it enabled them to convey motion to the
buckets with less wheelwork, shafting, and machinery than is generally required in dredging-engines,
whose works are frequently complex, and require considerable skill in their management.
1085.
,
1084.
P
1086.
SCALE.-3 feet=1 inch.
1087.
P
Figs. 1090 to 1099, show an elevation, plan, and section of the vessel and machinery.-a is the boiler,
constructed with internal fireplaces and flues similar to boilers commonly used for marine-engines.
b, steam-pipe leading from the steam-chest on the boiler to the engine. c is a condensing-engine of 20-
horse power, the cylinder being 27 inches diameter, and the length of stroke of piston 2 feet 9 inches.
The engine is constructed with side-beams on the marine principle, and the motion is communicated to
the fly-wheel shaft d, by a connecting-rod in the usual way. e is the fly-wheel. p is a friction-hoop,
which fits lightly around a drum or sheave keyed fast on to the fly-wheel shaft. The use of this
contrivance being to prevent accidents to the machinery, in case the buckets should get entangled with
any thing during the process of dredging, as when the resistance increases beyond what is necessary for
raising the soil, the drum or sheave slips round inside the hoop, and the buckets cease to work, whilst at
the same time the steam-engine may continue its motion without injuring the machinery. g is a pinion
bored to fit the fly-wheel shaft, (but not keyed fast to it,) having two strong stops or carries cast on one
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DREDGING, AND DREDGING-MACHINES
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side of it, which come in contact with corresponding stops on the wrought-iron ring or hoop. h is a
spur-wheel, which is driven by the pinion g. 2 is a pinion keyed on the intermediate shaft, which drives
the spur wheel j, keyed on the tumbler-shaft. 11 are clutch couplings for the purpose of connecting one
or both sets of buckets to the steam-engine, or disengaging them when required. m m m m are cast-iron
carriages, forming joints or hinges for supporting the bucket-ladders independent of the tumbler-shafts.
n n n n are the tumblers over which the chain and buckets work. 9999, &c., are the buckets, made of
boiler-plate, and bolted securely to the links of the chain in a peculiar way, more clearly described in
Figs. 1094 to 1096, where the buckets and links are shown on an enlarged scale, and in which, on the front
of the buckets, will be observed a kind of spade that is of steel, and attached to the bucket by rivets,
consequently easily renewed at any time when worn away; the bucket-chain runs on cast-iron rollers p p.
1088.
"
1089.
0
0
SOALE.-3 fect=1 inch.
The bucket-ladders are made partly of wood, having wooden sides with cast-iron king-posts and trans
verse trusses; with wooden struts and wrought-iron tie-bolts, with screws at the ends, so that they may
be tightened up when required. These ladders are remarkably strong, with comparatively light
materials.
The spout g is of wood, lined with sheet-iron, and has a joint at r to allow of the punts or barges being
equally loaded on both sides without turning them round. As when the outer end of the spout is raised
by means of the purchase z, the soil will escape at r, near to the side of the barge which is close to the
dredging-machine, on lowering down the outer end of the spout, the soil will be carried over to the
other side of the barge, thus insuring its being equally loaded. The bevel-wheels tttttt and shafts и и и,
Figs. 1091 and 1092, convey the motion from the steam-engine to the apparatus on deck for propelling
the vessel to and fro, raising or lowering the bucket-ladders, &c. The ladders are raised by chains
passing round the barrels v ", and working in the sheaved blocks bb, which are suspended from the
timber framing. The operation of raising the ladders is effected by connecting the barrels to the shafts
by the clutches w 10, which are worked to and fro by levers that pass through the deck of the vessel.
When the ladders require lowering, the clutches are drawn back and the ladders run down of themselves
to any depth which is desired, being regulated by a brake attached to the drums at x x, as shown in
Figs. 1091 and 1093.
The apparatus for propelling the vessel to and fro is fixed on the deck. yy are two curved cast-iron
barrels. By taking two or three turns of a rope or chain round these barrels, one under and the other
over, one of the ropes will draw the vessel ahead, whilst the other pays off the slack, and vice versa :
47
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DREDGING, AND DREDGING-MACHINES.
SCALE.-8 feet=1 inch.
1090.
B
A
>
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DREDGING, AND DREDGING-MACHINES. -
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DREDGING, AND DREDGING-MACHINES.
or by putting both ropes or chains the same way round these barrels, they will both act in pulling the
vessel in the same direction. It should be named that there is a friction-sheave placed between the
propelling machinery and the steam-engine, similar to that which is fixed upon the fly-wheel shaft, to
prevent the chains or ropes being broken in case of any obstructions.
The bucket-ladder, Fig. 1090, is composed partly of timber framing; the main timber M (which runs the
whole length) being eighteen inches deep and eight inches broad, connected by strong cast-iron crosses,
(not shown in the drawing, as it was thought they would only confuse the adjacent parts.) To give it
strength to bear the weight of the buckets with their contents, it is furnished with a cast-iron king-post k,
having two inch tie-bolts 88 connected to its lower extremity by a single and double forked joint,
through which joints and the king-post a pin passes, thus firmly uniting them at this point. The other
ends of the tie-bolts pass through snugs, cast on the top and bottom carriages at ends of ladder, and are
1092.
T
0
I
M
M
SCALE.-8 feet= 1 inch
n
n.
furnished with a screw for the purpose of setting them up, by means of a nut, should they at any time
become slack. There are also two wooden trusses ww, which take the strain of the framing, midway
between its centre and either end. This ladder is found sufficiently strong, and well adapted for
sustaining a heavy weight; at the same time it is extremely light in appearance.
The buckets are made of boiler-plate, the back being half an inch thick. The back plate rises con-
siderably above the other parts of the bucket, and slopes forward at an angle of about 25° towards
the front or lip of bucket, for the purpose of retaining the soil and preventing its being spilled during
its progress, after receiving it from the excavation, until it deposites the same in the barges alongside.
The form of this back plate prevents a grent loss of mud or other material, which would otherwise
be the result, and consequently a loss of time would follow, and the quantity of soil delivered would
not be adequate to the power of the steam-engine. All the other parts of bucket, (exclusive of the
back plate before mentioned,) are three-eighths of an inch thick. The buckets at present dig to a depth
of 24 feet, but greater depths may be obtained by merely lengthening the timber framing of ladder,
and adding a greater number of buckets and links, proportionate to the extended length.
As the bucket-links are given in the same drawing with the bucket, further description is deemed
superfluous; it may, however, be remarked, that the links pass over the tumblers with perfect ease,
and without noise, owing to there being no projections on their lower sides, as the requisite strength
round the pins is carried above the centre of the link, and not on each side, as is frequently the case.
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DREDGING, AND DREDGING-MACHINES.
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The upper or tumbler shaft 8 8 8, Fig. 1092, is in three lengths, having two coupling-boxes 11 fitted to
them, for the purpose of working either one set of buckets or two sets simultaneously; the bearings or
journals of the shafts are four in number, seven inches in diameter and nine inches in length, and
working in plummer-blocks, resting on four timber frames ffff. The intermediate or middle shaft ii
has bearings five inches and three-quarters diameter and eight inches in length, working also in
plummer-blocks, which rest on wooden framing ff; and the lower or fly-wheel shaft d, has bearings
five inches and three-quarters diameter and eight inches in length, one bearing of which rests on the
engine-frame, and the other on the timber framing. These timber frames are severally connected at
their tops by a strong transverse beam TT, 20 inches deep and 18 inches broad, the outer ends of
which support carriages (to be hereafter described) for carrying the ladders, &c. By this arrangement,
and by being securely fastened at their bases, the four upright timber frames are firmly kept in their
perpendicular position. The form of these frames will be clearly understood by reference to the eleva-
tion, Fig. 1090.
It will be seen that the outer or hanging carriages m m, Fig. 1092, are connected to the ends of the trans-
verse beam in rather a novel manner ; the hanging part, or part beneath the beam, being attached to the
1095.
1096.
1094
SCALE.-4 feet=3 inches.
cap or top plate by means of twelve 14-inch bolts, by which method it can be securely fastened to
the before-mentioned beam, and adjusted 80 as to accommodate the tumbler-shaft, by means of pack-
ings being introduced between the cap and top of timber, and which can easily be removed at any
time when required.
Figs. 1097 to 1099 consist of a detailed plan and section of top and bottom tumblers; they being of
essential consequence to the efficient working of the machine, are therefore minutely delineated in an
extended scale, thereby rendering the design more easily understood than by a lengthened description,
which it would otherwise require. It may be observed, however, that they are of cast-iron, and the corners
only being liable to derangement, are separate pieces, consequently easily removed when required.
The engine with its machinery has raised 160 tons of soil per hour, upon an average one set of
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DREDGING, AND DREDGING-MACHINES.
1093.
m
SCALE.-8 feet=1 inch.
B
1099.
1097.
-
1098.
SCALE.-4 feet=3 inches.
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DREDGING, AND DREDGING-MACHINES
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buckets only having been employed in the performance, with a weight of three pounds and a half per
square inch upon the safety-valve of the boiler.
It may be remarked, in conclusion, that the boat is supplied with a bilge-pump for discharging the
bilge-water, and a deck-winch for moving the boat by hand when the engine is not working. The chain
for raising the lower end of the ladder, is five-eighths of an inch in diameter, of the description called
" short link." The draught of water is three feet six inches, with every thing on board, and the bottom
is perfectly flat, and both ends are of the same form.
Specification for a Dredging Vessel of the following dimensions.
Ft. In.
Ft. In.
Length of deck
80 6
Depth in hold
5 4
Breadth, extreme
22 1
Tonnage 16931.
The scantlings as follows:-
in.
In.
Chine, elm, or beech
12 by 14
Floor timbers, elm or birch
91 10
Kelson timbers, elm or birch
12 - 11
Stems, oak, sided 8 inches, moulded 9 inches.
1 deck hook, oak, at each end sided 9 inches.
Aprons,
"
8
"
"
8
"
1 breast hook,
=
"
"
Timbers,
"
6
"
head 6 "
Stancheons,
"
"
5
a
Stemson knee, at each end sided
7
"
Winch-bits
"
"
6 X 71
"
Deck beams, oak, sided 71, moulded 81 u
Propelling gear-bits, oak
9 X 111 "
Deck knees,
"
5
Plank :-
Bottom
34 inch elm.
Deck
24 inch yellow pine.
Outside
21
64
"
Bulwark
11
"
"
Clamps
41 "
"
Roughtree rail
4
X
21
"
oak.
Plank-sheer
21
"
"
Iron work
Butt bolts in bottom and sides
1 inch.
Stemson knees and breast hooks
1 inch.
6 pair of iron knees in the wake of boiler and engine t cwt, each fastened with 1-inch iron.
Deck, 5-inch spikes.
Deck fastenings all of iron.
The vessel to have both ends alike, with a break in the deck both fore and abaft.
The platform of 2-inch yellow pine round the boiler for the stowage of coals, and 14-inch yellow pine
in the engine-room and cabins.
Description and specification of a Dredging-machine, constructed by Messrs. Girdwood and Co., of
Glasgow, for the excavation of the River Clyde. Figs. 1100 to 1103, exhibit an elevation, plan, and
section of the engine and dredging apparatus, the letters of reference corresponding in each figure or
separate view of the design.
The timbers of this vessel are all exactly similar in specified variety and dimensions to that by
Messrs. Summers and Co., as already minutely detailed, but the external dimensions of the vessel are a
little different, viz. entire length on deck 90 feet; extreme breadth 22 feet; height from ceiling to ceil-
ing seven feet; and when all is on board and in complete working condition, the draught of water is
about four feet. Six is the number of men employed on board.
A, Figs. 1100 and 1101, represents the boiler, and B the engine; both of which are of the usual construc-
tion adapted to marine purposes. The cylinder of the engine is 26 inches diameter; length of stroke 21 feet
number of strokes per minute 44; and requires about 2 cwt. of good coal per hour for the generating of a
sufficient supply of steam. In effect, the engine will lift, from a depth of 18 feet, about 110 tons of mud
or clay per hour, or 160 tons of sand or gravel in the same time; but in very hard ground, and inter-
mixed with stones, no proper data can be given. The vessel is moved forward by the power of the
engine, through means of the bevel-wheels, shafting, pitch-chain, &c., as shown in each design, and
which communicates motion (when required) to, and by means of the double-acting winch R, and when
the buckets are working in mud or clay, the vessel is caused to advance at the rate of about four feet
per minute, when in gravel or sand at 21 feet per minute, and the number of buckets delivered is 14
in that space of time.
With regard to the movement of the buckets, motion is given to the wheels C and D by the crank-
shaft S of the engine, and communicated by the line of shafting eec, &c., to the wheels F and G; from
thence to the buckets by the barrel or tumbler T, that being made fast upon the spindle I, which is of
malleable-iron, eight inches diameter, and on which the wheel G is fixed. The small wheel C is three
feet three inches in diameter; the cog-wheel D is seven feet diameter; the shafts ce, &c. are of cast-
iron, 61 inches diameter in the bearings; the bevel-pinion F is two feet three inches diameter, and the
bevel-wheel G is six feet, and makes seven revolutions per minute; the top or upper tumbler T has four
sides, and the bottom tumbler V five; as when they are thus formed, the motion of the buckets is
found in practice to work more steady, and, consequently, the effects rendered more complete.
The bucket-frame H, acting upon I as a centre, is also regulated to a proper depth of water by the
power of the engine; the bevel-wheel K upon the crank-shaft S gives motion by means of the wheels
1 m n, to the barrel r, and round which the chain of the tackle passes, as shown distinctly in the
elevation.
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DREDGING, AND DREDGING-MACHINES.
Feet.
1100.
89
STATE
INSURANCE
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The wheels K and I are each two feet four inches diameter; the pinion m on the bottom of the shaft t
is 10 inches diameter, and the wheel n four feet two inches. On the same shaft with the bevel-wheel
n is fixed a spur-pinion g, of one foot seven inches diameter, which gives motion to the wheel o, of three
feet three inches; the motion is communicated (when required) by means of the clutch c c, and, when
the frame H is raised to a sufficient height, and placed at the requisite depth of water, farther motion
of the barrel is prevented through disengaging the clutch by means of the lever W, and the barrel
rendered stationary by the lever and friction-pulley yy. The clutch is two feet four inches diameter;
the friction-pulley is three feet eight inches diameter, and its breadth of strap 31 inches. The length
of the chain-barrel r is 41 feet, and its diameter two feet. The shaft t is 41 inches diameter, and the
barrel-shaft 51 inches, each being of cast-iron.
The following is the number of teeth that each of the preceding named wheels contains, also the
pitch and breadth upon the face:
Wheel or Pinion.
Number of Teeth.
Pitch.
Breadth.
Spur-pinion on crank-shaft C
49
21 in.
81 in.
Cog-wheel on end of laying-shaft D
112
21
81
Bevel-pinion, marked F
27
31
8
Bevel-wheel
"
G
72
31
8
Mitre-wheels
"
Kand /
44
2
41
Bevel-pinion
"
m
15
21
4,
Bevel-wheel
"
n
75
21
41
Spur-pinion g on shaft with и
35
21
5
Spur-wheel o on chain barrel-shaft
51
5
A
o
o
o
0
o
o
o
00
III
III
B
1102.
1103.
o
C
o
a
go
D
The Bucket-Frame, Buckets, Links, dcc.-The bucket-frame is of the best red pine, strongly trussed,
and strapped with iron, and in form and dimensions similar to the bucket-frame already described in
the preceding machine; in length it is 55 feet 4 inches, and the number of buckets thirty-four, each'
bucket being 261 inches wide, 16 inches broad, 17 inches deep, and formed of the best plate-iron I inch
in thickness; on the back or sole plate p, of each bucket, and immediately beyond its formation, is an
attached piece or continuation of the plate, so as to form a covering to the joints of the links, and so
prevent any injurious effects from the constant liability of contact with the excavated materials; also
48
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DREDGING, AND DREDGING-MACHINES.
on the front of the buckets are fixed
pieces of iron shod or edged with
1101.
steel, for the purpose of increasing
the strength of that portion of the
bucket, and the better adapting of the
same for coming in contact with hard
materials; likewise that of being easi-
ly removed when required for repair.
The links x x x, &c., that connect
the buckets, are of wrought-iron, each
link being 21 inches from centre to
centre of joint; flanges are formed on
the double links, as shown in the de-
sign, 21 by fths of an inch, and to
which the buckets are fixed by fths
of an inch rivets; the diameter of the
joints is 34 inches with & inch project-
ing on each side, to increase the sur-
face of bearing for the pins: all the
joints and pins are cased with steel
and properly hardened.
The rollers rrr, &c., are for the
proper conducting of the buckets
along the frame H, and are of cast-
iron 8 inches in diameter, with axles
or bearings of wrought-iron, 11 inch
diameter, and which revolve in cast-
iron receptacles or bushes. The ends
of the tumblers also revolve in cast-
iron bushes, that metal being found
TO
more durable, for this purpose, than
any hitherto tried.
It may not be out of place here, as
being through the means of the action
of the buckets and bucket-frame, to
remark an idea or system given by a
correspondent in the " Civil Engineer
Feet.
and Architect's Journal," which he
calls radius cutting, in distinction to
that of the common practice called
trench cutting, and which no doubt
in various instances must be of con-
siderable advantage. In the ordinary
method called trench cutting, the
power applied to lead the machine
ahead into the cutting, has also to re-
sist the reaction of the buckets. Now,
in radius cutting. the chain from the
bow of the vessel is not wound up
while it is cutting, but is only shorten-
ed at each return of the machine, and
which causes a swinging motion of the
0
vessel to take place, the machine
0
0
being led laterally to the cutting by
0
the side chains; and which are com-
paratively easy to work. as the reae-
H
tion of the buckets is mostly against
the bow or radius chain.
In respect to any inconvenience at-
tending the use of these lateral chains,
in a harbor or narrow navigation, it is
no more than in the ordinary method,
as corresponding chains are then re-
quired to keep the machine in line,
and these are necessarily used on
both sides at once; whereas, in the
other system. these lateral chains are
only tightened on one side, namely,
that on which the machine may hap-
pen to be traversing; and where it is
required to lower them, to allow ves-
sels to pass, they only again require
to be tightened up sufficiently to let
the buckets fill.
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DREDGING AND RAISING MACHINE.
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It may be contended that, to cut or trench a bank in the proper current, will, by changing the currents
and eddies, remove it by a natural process; but, as this is a point 80 difficult to hit upon, it is generally
allowed that, to get large stones and rocks taken up, and to cut the surface fair, is the surest way of
reducing a bank, and of leaving it in the condition least liable to "slit up."
The difference of construction in the machine is trifling, 80 as to adapt it to the radius principle, being
only the doing away with the flanges on the bottom tumbler, and substituting in their stead "snugs" on
the tumbler between the chains or links, to prevent their getting off. But it must be borne in mind in
the constructing of dredging-machines for whatever kind of cutting, that a proper means be effected for
preserving the chains employed in taking the vessel ahead, when the power of the engine is applied;
and the best method that I am at present aware of is that of "conical friction."
The excavated material from the dredging-machines is carried away by punts, or large rectangular
boxes of plate-iron. In dimensions, they are each 32 feet in length, 14 in breadth, and 3 in depth
through the deck of which is an opening 27 feet 8 inches by 10 feet 4, and around this opening is a
cooming 10 inches in height, as a prevention to the stuff getting over upon the deck; each punt carries
on an average 20 to 22 tons, and a small steam-tug of 70-horse power takes from 18 to 20 loaded punts
at one time.
Literal References-Figs. 1078 and 1079.-Machine for raising mud out of Messrs. Perry & Well's
Dock at Blackwall.
a. Horse-bar.
b. First motion bevel-wheel for transferring the vertical motion given by the horse-bar to the horizontal
one required.
c. Corresponding bevel-wheel on horizontal shaft.
d. Horizontal shaft, on which is fixed
c. A spur-wheel.
fg. Are two spur-wheels, by means of which motion is given to
h. Reel-shaft.
i. The reels are at each end of the ladder round which the buckets pass.
k. The ladder, which can be raised or lowered by the tackle to the required depth
l. The buckets for raising the mud.
m. A shoot for delivering the mud from the buckets into
n. A barge alongside.
o. A trap-door at the bottom of the bridge for discharging the mud.
p. A pinion on horizontal shaft for working the windlass, by means of which, as the dredging pro-
gresses, the machine is hauled ahead.
DREDGING AND RAISING MACHINE, by J. Hart, of Middletown, Connecticut.
Fig. 1104 is a horizontal plan of the mud dredging-machine.
Fig. 1105 is a vertical section.
A is a large flat vessel for receiving the boilers, fuel, engine, and principal parts of the machinery.
B is a small vessel for stores, &c., strongly connected to the larger one with the vibrating ways c for
the buckets, strongly hung between the two vessels in a gallows-frame.
A is a crank, by which the power is to work the whole machinery, fixed on one end of the shaft b,
which is strongly mounted in framing c.
On the shaft b is the fly-wheel e, and between that and opposite bearing is the clutch f, sliding on
the shaft b, into or out of the clutch part of the driving pinion g, which geers into the larger tooth-wheel
h mounted on that end of the bucket-shaft i; on this the chain-wheels k k are fitted, each wheel made
with four shifting-studs to lock into the long links of the bucket-chain. This chain is made so that each
flat link has a curve to fit the wheels kk.
The edge link has a strong iron brace [' put in given lengths.
A connecting link is inserted, made with an open side turned up to receive a doubled-eyed collar.
In this mode of making a chain in sections, and using only four spurs or teeth, a chain can be worn
one inch at each end, and not ride or turn on the teeth or spurs; each end of the links is lined with
steel.
When worn or broken a section can be taken out to be repaired and replaced by another.
The chain-wheel h k is a skeleton cast wheel to receive a shifting sectional stud or spur, with bolts to
hold them in, which takes the strain off the chain, and allows them to be taken out and replaced by
others when worn.
The friction rollers and water chain-wheel run on sleeves.
The raising and lowering of the buckets is effected by the slings and yoke in i, Fig. 1105, and chain
h½, which goes over the sheeve o, mounted on the double davit P. thence under the chain-wheel g to a
sheeve at the head of the gallows-frame, and having at its inner end a counter-weight.
The chain-wheel g, fitted with a groove and studs to match the chain h½, is mounted on a shaft fitted
in bearings, and having the tooth-wheel w on one end, where it geers into the pinion x, which is fitted to
a shaft mounted on bearings, and carrying on it the raising or lowering wheel E; this is made so that
it serves as a hand-wheel by the spokes 41, and as a drum by the flanged rim x¹, and through it the
ways are regulated by the directing workman, who stands on the deck.
Immediately over the fly-wheel e, Fig. 1104, a frame i, Fig. 1105, is laid, to receive the bearing of
the shaft " on one part, forming a winch h1, Fig. 1104.
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DREDGING AND RAISING MACHINE.
1104.
X
X
X
X
SCALE.-25 feet=3 inches.
X
A
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OF
1105.
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DRESSING-MACHINES.
At the other end, the drum sl is mounted, and over this is placed the belt, so that it hangs loosely
around and below the fly-wheel e, and is kept from contact with it by the small rollers q¹ q², mounted
below the drum 8¹, when not required in use in the pit. Formed by the frame which carries the drum
s¹, are the two tightening drums p'p' shown in Fig. 1104, as set over the fly-wheel these are hung
in the swing-frames 0¹ 0ª.
The upper part of each of these frames terminates in arms u³, and at one end of the frame x1 is
the vertical davit and sheeve m²; a rope 11 goes from the arm u² round the sheeve m2 and returns and
fastens to the arm u³, and thence leads to the frame over the deck w¹.
The winch k¹, Fig. 1104, receives one end of rope i¹, the other end of the rope being attached to the
drum x¹ on the wheel E; and the tooth-wheel is fitted with a pawl h1 to retain it in its place as wanted.
This part of the apparatus is to be used as follows: when the buckets are to be lowered, the attending
laborer lifts the pawl h' back and turns the ways-wheel E in the direction of the arrow 1 by the spokes
y'; this lowers the ways, and at the same time is winding the rope il off the windlass k': the belt r
being slack does not hinder the operation of lowering.
When the bucket and ways are to be raised, the attendant laborer leaves the wheel E and simply
hauls on the rope l¹, which pulls the arms u" and u³ outwards, and forces the drums p¹ inwards
against the belt below in contact with the rim of the fly-wheel e, whose motion round drives the rais-
ing-wheel E round in the direction of k¹, raising the ways and buckets easily and rapidly.
Near the machinery in the smaller vessel B, projecting over the end, is a frame forming a slide,
carrying the anchor-post. This is raised by a chain running through sheeves; then by taking a turn
around the end of the bucket-shaft i, the end forms a windlass barrel for that purpose. This anchor-
post holds one end of the machine; the other end is moved the width of the buckets at a time by a
pawl, windlass, and lines.
This machine, working with a ten-horse power engine, will excavate, on an average, 600 yards a day.
It delivers ten buckets of nine cubic feet a minute. The one now at work in the New York slips has
worked four years, and has not lost three days in the year by being out of repair.
DRESSING-MACHINES. The dressing-machines used in this country are made upon an entirely
different construction from those used in England.
Fig. 1109 represents a side view of the dressing-machines used at Lowell and its vicinity.
A A is the centre-frame, supporting the centre-beam a, containing the dressed yarn.
The wheel E, on the centre-beam, is fastened with a set-screw, so as to be easily taken off when a
full beam is to be removed, and put on the empty beam which is to replace it.
BBB to the right and left are the section-frames, all made of wood, containing the section-beams
HHHH.
The ends of the section-beams are of cast-iron, with a square groove for receiving a friction-strap, and
a weight represented at
The sizing-rollers are represented at
The yarn as it leaves the section-beams, passes through a raddle or ravel, made of small pieces of
hard wood, and represented at u u,-from that, through between the sizing-rollers,-again, through
a brass wire reed at o,-through a copperplate supported by b,-through another brass wire reed
at dd-and under the measuring-rollers N N,-at which place the yarn from the four beams on each
section are, for the first time, brought all into one horizontal plane.
From the rollers NN, the two sections of dressed yarn pass up through heddles at k, called the lease-
harness; from that it is wound on to the centre-beam a, at the top.
The lease-harness may be shifted to either side of the frame by means of a screw at k, and only one
section of the dressed yarn goes through heddle-eyes in the lease-harness; 80 that when a full beam is
to be removed, a lease-rod is introduced between the two sections of yarn above the harness; then, by
drawing the harness to one side, another lease is formed, into which a rod is introduced.
The different operations of the machine are effected in the following manner. F are the fast and
loose belt-pulleys, driven by a belt from the room below; n n are two cones, that to the right being
driven from the one to the left, by the cross-belt R. On the axis of the cone to the right hand, there is
a small bevel-wheel working into another on the bottom of the upright shaft rr. On the top of the
upright shaft there is a small bevel-wheel working into the wheel c; and on the axis of the wheel
c, there is a small spur-geer, not seen in the engraving, working into the wheel E, on the centre-beam a.
Motion being thus given to the cone on the left hand, (by the belt-pulley F which is fastened on the
same shaft,) it is next communicated by the belt R to that on the right, and from it to the beam on the
top, containing the dressed yarn; hence the speed of the centre-beam a, on the top of the centre-
frame, may be increased or decreased, by shifting the belt R, on the cones n n.
The brush-motion is next to be considered. DDD are the brush-racks, or brush-fraines; they are not
fastened to the section-beam frames BBB, but are fitted so as to move up and down, short spears z 2
being fixed to the top and bottom of each side of the brush-frames, which slide into the eyes of studs,
and serve to keep them in their proper position, as well as to let them move freely up and down 8 8 8 8
are small blocks of cast-iron, which are fitted to slide freely on the polished steel-rods hhhh; the
dotted lines represent straps or belts passing over small pulleys on each side, and descending down to
the large wooden pulleys G G, to the surface of which the belts are fastened: the blocks 8 8 8 8 are
fastened to the belts by a small nut and screw on the under side, whilst the brushes rest on the blocks
above. The feathers represented on the blocks at 8 8 8, fit into slits in the ends of the brushes. W W
represent two beams of wood, (one at each side of the machine,) about four inches broad, and three
inches thick, called sweeps; these are supported in the centre at f, and at the end towards the left
hand, they are attached to the lever PP, the under point of which supports the whole brush-frame
the other end of the sweeps being attached to the block i, towards the right hand: the block i is a
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projection from a shaft, extending across the machine at each section, the axis of which is seen at x,
and the pulleys G G are fastened on each end of this shaft. By carefully examining the engraving of
the various parts of the machine, the reciprocating motion of the brushes, together with the up and
down motion of the brush-frames, will now be easily understood. The lever J is connected with a
aliding-crank on the axis of the cone n, towards the left hand; consequently, the revolving of the crank
moves the sweeps alternately, from section to section; and the end of the sweeps to the right hand,
being attached to the block i by a strap of belt leather, the alternate motion of the sweeps moves the
shaft x, and with it the pulleys G G, about one-fourth of a revolution each way this reciprocating
motion of the pulleys, draws each end of the straps represented by the dotted lines, and thereby pro-
duces the necessary reciprocating movements of the
brushes upon the yarn; while, at the same time,
the other end of the sweeps towards the left hand,
H
by means of the lever PP, raises the brush-frame,
and with it the brushes, up and down at every alter-
B
nate stroke. Thus, when the brushes are at hhhh,
2
the frame is down, and they are then in a proper
position for moving along the surface of the yarn,
B
B
(which has just been coated with size, in passing
through between the sizing-rollers,) and having
made one full stroke, they are then at the opposite
side of the frame, which is immediately raised by
the lever PP, connected with the sweeps; and in
raising the frame, the brushes are lifted out of the
yarn, until they return to their former position at
hhhh. The whole movements of the machine com-
mence at the cone n towards the left hand. From
it, motion is communicated by the belt R, to the
opposite cone, and from it, to the centre-beam a at
the top; and from it, (the cone n,) motion is also
communicated by the sliding-crank, and the con-
necting-lever J, to the sweeps W W, of which there
are two, and the one end of each moves the brushes
alternately from side to side, whilst the other end
produces the up and down motion of the brush-
frame. The whole machine is extremely simple,
and all its different movements 80 contrived, that
they can easily be adjusted so as to operate with
1109.
A
the most perfect accuracy.
SCALE.-4 feet=1 inch.
LL represent the fanners enclosed in wooden
boxes, open only at the centres for admitting a cur-
rent of air, and at the mouths QQ, for throwing it
out: by this method of confining the air, it rushes
X
out with much greater force, and the mouths Q Q
are made so as to direct it right up amongst the
dressed yarn. The fanners here represented have
four wings each, but some have only two or three
that to the left hand, is driven by a belt from the
room below, and from it, a cross-belt communicates
motion to the one on the right. X is a hot-air pipe,
with a branch extending up to the hot-air box M,
placed between the two rollers NN. The cover of
this box extends till within one half-inch of each side,
which leaves a small opening for the escape of the
e
air, which issues out at each side upon the yarn, and
wing entirely hot air, it has a peculiar effect in ab-
sorbing any remaining moisture upon the yarn, be-
fore it is wound on to the centre-beam a, on the top.
Instead of the hot-air box M, some dressing-frames
have a centre fanner, similar to those used about
H
I
Manchester.
The sizing-rollers yyyy, are generally made of
soapstone, with an iron axis; the under roller only is covered with cloth: one of these rollers, when
finished, costs about eight dollars.
The two sections of these dressing-machines may be extended out as far as may be thought necessary.
In order to diminish the size of the plate, the distance from the centre of the section-beams to the
centre of the frame, is represented as only 91 feet; some, however, extend to 17 or 18 feet. As the
greater the distance from the sizing-rollers to the centre-beam containing the dressed yarn, more time
will be gained for drying; but when the section-beams are stretched out too far, the yarn is more liable
to break with the drag of the centre-beam.
On one end of the axis of the measuring-rollers N N, there is a screw or worm working into geers,
connected with an index which points out the number of yards of dressed yarn on the centre-beam;
every 33 yards is marked with paint, which allows 30 yards of cloth to each piece, the 8 yards (equal
to 10 per cent.) being allowed for shrinkage in the weaving, &c.
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DRESSING MILLSTONES.
The measuring-rollers, in general, are common wooden cylinders, about eight inches in diameter
some are revolving steam-cylinders, which, when properly packed at the journals so as to prevent
the steam from escaping, has the best effect of any thing that has yet been tried for drying the yarn
speedily.
The average produce of these machines is very variable. In some factories, their average produce
will be about 14 pieces per day to suit a 900 reed; yarn, Nos. 14's to 18's. In other factories, on the
same kind of work, these machines will dress 20, in others 80, 40, 50, and 60 pieces per day. Some of
those fitted up with revolving steam-cylinders, are said to produce even 70 pieces on the same kind of
work, viz., coarse 900s, yarn No. 14's. One great cause of this difference in the quantity produced from
the dressing-machines, arises from the different temperatures in the apartments where they are in opera-
tion, as well as from the mode of applying the heat to the dressed yarn. In some factories the dressing-
machines are in the same room with the looms, where the temperature seldom exceeds 75°. Those
mounted with steam-cylinders, in place of wooden measuring-rollers, generally produce the grentest
quantity of work; next to these, are those with the hot-air pipes; and next to the latter, are those with
three fanners, that is, one at each side, and one in the centre. Those with only two fanners, produce
the least quantity of work.
The size used for dressing is generally made of potato starch for all coarse work; and of flour for the
finer goods, or such as are intended for printing. The mode of preparing the starch for size requires
particular attention; and although different places may have different methods, the two following have
been found to suit the purpose remarkably well.
1. Method of making Size from Potato Starch for coarse Goods.-2} gallons of yeast, and 2 quarts
of vinegar, to be well mixed with about 9 gallons of water, which has been previously heated to 120°,
or as hot as the hand will bear to work in it. To these are added 125 lbs. of potato starch. The whole
is then allowed to stand in a warm place about 10 or 12 days, or until it is perfectly fermented; then 81
lbs. of common clean tallow is dissolved in 75 gallons of water, heated to 160°, to which are added
75 lbs. of the fermented starch. The whole is well stirred until all the ingredients are perfectly incorpo-
rated. The size is then to be used immediately before, or after it is perfectly cooled down. To the above
some add about 21 lbs. of the sulphate of copper, to prevent mould.
The above makes a very superior size. It is smooth, clean, and entirely free from any offensive
smell; and although about the same price as flour, it is found to answer the purpose much better for
coarse goods; very little of it adheres to the yarn, yet quite enough to make it weave well.
2. Method of making Size from Flour for the finer Goods.300 lbs. of flour mixed in 45 gallons of
water, and allowed to stand for four or five days at blood-heat, until it is perfectly fermented; this is
called yeast. To the above are added about 140 gallons of water heated to 180°. The whole is then
boiled by steam from 30 to 45 minutes. At first it boils thick, but by continued boiling it becomes thin
in the middle, when it is considered done; after which it should stand over one week, and be reduced
with cold water when used.
The following mode of making Size from Flour is practised in Glasgow for various kinds of Goods :-
One barrel of flour is soaked in water which had been previously heated a little over 120°, and allowed
to stand in this state about a week, or until it ferment thoroughly. It is then mixed with about 110
gallons of water in a copper boiler, with a cast-iron casing; and by introducing steam into the boiler, as
well as into the vacant space between the casing and the boiler, it is gradually heated until it boils;
after which the steam may be admitted at any pressure, and the boiling process continued about an
hour; during which an agitator, driven by the engine, moves round with a slow motion, until all the
concretions or lumps are completely dissolved, when a wooden roller being dipped into it, if the small
portion which adheres to the roller has a thick, smooth, glutinous appearance, it is then ready to be
emptied out into narrow deep vessels to cool, in which it is allowed to stand for three or four days
before using it.
Besides the kind of dressing-frame just described, there is another made at Providence, Rhode
Island, and generally used throughout that part of the country, known by the name of Pitcher and
Gay's dressing-frame. The principal difference between it and the one already described, is, that the
former has four pairs of sizing-rollers on each section, while the latter has only two; that is, the yarn
from the two upper beams passes through between one pair of sizing-rollers, and that from the two
under beams through another pair.
DRESSING MILLSTONES, Machine for. We have had occasion to notice, in our descriptions of
corn-grinding machinery, the frequency with which it is found necessary to renew the grinding surfaces
of the stones, and the great care and accuracy to be observed in thus preparing them for their work.
The operation consists in roughening the surface of the stone, when worn smooth, by cutting delicate
and very regular furrows between each of the radial grooves and parallel to them, and depressing the
latter to a degree corresponding with the amount of the grinding surface removed. Skilful and expe-
rienced workmen are employed for this service, which they accomplish by the help of hammers, pro-
vided with chisel-edges, of well-tempered cast-steel.
Simple as this operation may appear, the attempts bitherto made to perform it entirely by machinery
have proved abortive; and we need not be surprised at this, when we consider the various degrees of
hardness and compactness presented by different parts of the same stone, as well as the differences in
the nature of the grain which is to come under its action. To accommodate itself efficiently to such
circumstances, a machine would almost require of itself to possess intelligence. But although it may
safely be pronounced impossible to dispense with manual labor in this process, it may be accomplished
with much greater dispatch and precision by the use of the simple machine, or more properly instrument,
which we have represented in Figs. 1110 to 1121.
This instrument serves simply to guide the hand of the workman. and to restrict the cutting edge of
the hammer into a perfectly parallel and rectilinear course; the force and number of the blows being
left entirely to the discretion of the workman. By a simple contrivance, it is also made available for
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regulating with the greatest nicety the degree of fineness, or in other words, the distance between the
furrows, of the grinding surface of the stones, according to the nature of the work on which they are to
be employed.
Fig. 1110 is a side elevation; Fig. 1111 an end view ; and Fig. 1112 a plan of the entire machine.
Figs. 1113 and 1114 are views of the hammers and cutting tool detached from the machine.
Figs. 1115 and 1117, a sectional view and corresponding plan of the axis E, and its screw and nut.
Figs. 1116 and 1118, detached views of the saddle or guide for the hammer.
Figs. 1119, 1120, and 1121, represent the various handles used for varying the distance between the
cuts; the first having five, the second six, and the third four rays or points.
1110.
1112
-
0)
SCALE.-1 foot=1 inch.
1119.
1120.
1121.
1113.
1115.
1117.
1111.
1116.
1118.
1114.
The base of this machine, which simply rests, without being fixed, upon the dressed surface of the
millstone A, consists of a narrow cast-iron plate B, also dressed on its under surface. and of sufficient
weight to retain it in the position in which it is set, without at the same time impairing its portable
character. On this sole-plate a carriage C is fitted to traverse longitudinally; being supported at one
side by a smooth cylindrical rod D, bolted to the sole-plate, and passing through the brass-mounted
sockets aa; while, at the other side, it is provided with small friction-rollers bb, resting on the sole-
plate. At right angles to the direction of this motion, an axis E is fitted to slide on bearings cast upon
the carriage C; the outer extremity of this axis is formed into a screw, worked by the nut F; and the
opposite end, which is cranked, carries the saddle G, into which the hammer-handle H is inserted, and
which guides the action of the cutting-tool. The nut F is elongated so as entirely to enclose the screw
and protect it from injury it is also provided with a set of star-handles cc'c", either of which may be
affixed to it according to the degree of fineness which it is required to give to the stone. The first has
49
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DRILLING-MACHINE
six rays, and gives the greatest degree of fineness, the distance between the cuts being only one-sixth of
the pitch of the screw; the others, having fewer rays, give correspondingly increased roughness to the
stone. A species of index d, fixed to the carriage, serves to regulate the exact amount of motion given
to the nut. The cranked form given to the axis E is for the purpose of adapting the machine to the
length of the cutting-tool I. The manner in which this adjustment is accomplished will be obvious
from Inspection of the drawings.
Action of the Machine.-This instrument being laid upon the surface of the stone, with the edge of
its sole-plate exactly parallel to one of the great radial grooves, the carriage C is pushed by the hand
of the workman towards the circumference of the stone, until the cutting-tool I reaches it.
He then begins his strokes, varying the number and intensity of them according to the hardness of
the stone, and the depth he wishes to give to the furrows; and drawing the carriage C slowly with his
left hand towards the centre of the stone, until the whole grinding surface is traversed by the tool.
The hammer is then set into the position for making the next adjacent furrow, by turning the handle c
through another of its divisions; the carriage is again slid towards the circumference, and the operation
continued as before. Thus the requisite straightness, regularity, and parallelism of the grooves is en-
sured and the operation of dressing materially facilitated.
A, the millstone to be re-cut.
B, the base-plate of the machine.
C, the carriage or support of the working parts of the machine.
a a, straps of iron binding the carriage to the cylindrical rod D.
bb, friction-rollers between the carriage and sole-plate.
D D, a cylindrical horizontal rod, turned smooth, for guiding the carriage C into a rectilinear move-
ment.
E, an axis sliding transversely in bearings, and carrying the guide for the hammer.
F, nut by which the position and motions of the axis E are determined.
c c c, star-handles for regulating the fineness of the cut; the first having six, the second five, and the
third four rays.
d, an index for regulating the exact amount of travel given to the nut F.
G, a cast-iron saddle fitting to the cranked end of the axis E, and serving as a guide to the hammer.
H, the wooden handle of the hammer.
I, the chisel or cutting-tool inserted into the head of the hammer.
DRILLING-MACHINE, by Messrs. Joseph Whitworth & Co., Manchester. This machine answers
all the purposes for which tools of this kind are intended, and is made self-acting in all its motions.
Fig. 1122 is a vertical section in the plane of the axis of the driving-cone and work-table.
Fig. 1123 is a front view of the machine, agreeing in its letters of reference with Fig. 1122.
The other figures are drawings of the parts of the machine, which are necessary to a full description
of its construction and motions, and have the same letters of reference.
A A A A indicate the form of the cast-iron framing of the machine, upon which all the working parts
are carried, as also the work-table and its motions. This framing is formed of a single casting, and is
fixed by three strong bolts upon the sole-plate TT, intended to rest solidly, and without any fastening,
upon the floor of the workshop.
On the upper portion of the main frame a strong bracket is cast, which serves to carry the outer ends
of the cone spindle b, and back-speed spindle of the machine. Upon the spindle b is the driving-cone
B of three speeds, the spur-wheel C, and the bevel-pinion D. The speed-cone B is loose upon the shaft,
and only communicates motion to it by means of the spur-wheel C, which is keyed upon the spindle,
and to which the cone can be attached by a stud-pin and nut at c. This wheel geers with the pinion E,
on the same spindle which carries the wheel M; this in turn geers with the pinion N, which is fast upon
the end of the cone B, but runs loose upon the cone-spindle b.
This arrangement is in every respect the same as the ordinary back-speed of a lathe, and serves the
same purpose. Supposing the back-speed removed, the cone being driven by its belt causes the spindle
b to revolve, in consequence of its attachment to the fast-wheel C, and at the same time gives motion
directly to the bevel-pinion D on the end of the spindle. This again geers with the bevel-wheel F, on
the dríll-spindle G G, which is free to slide vertically in the eye of the wheel, while at the same time it
is prevented from revolving in it by a sunk feather. By this means three different degrees of quick
speed may be communicated to the drill. But let the back-speed be in geer, as represented in the
drawing, Fig. 1122, and let the stud-pin c be removed, and the cone thereby loosened from its attach-
ment with the wheel C, the motion being communicated to it will not drive the shaft b, directly as be-
fore, but the pinion N being fast upon it will give motion to the wheel M, upon the same spindle with
the pinion E. This last will therefore make the same number of revolutions as M, but being less in
diameter will convey a proportionally less velocity to the wheel C, with which it geers, and which it
consequently drives with a speed diminished in the ratio of the geering pairs. Now the wheel C
being fast on the shaft b, conveys through it to the bevel-pinion D the same diminished speed, and
this again to the drill-spindle G G. This reduced speed may, of course, be varied as before, by
placing the belt on one pulley or other of the speed cone.
Behind the pinion E there is a recess cast in the framing, to allow it to enter when the back-speed
wheels are to be thrown out of geer; and it may be remarked that this speed-geer is only required to
be in action when the machine is employed in boring holes of upwards of an inch and a half in
diameter.
The wheel F is cast with a long hollow boss, which is turned and fitted into a brass collar in the
lower branch of the carrying-bracket, as seen in Fig. 1122. This collar is kept in its place by a cover
bolted over it, as shown in Fig. 1123.
As already observed, the drill-spindle passes through the wheel F. which thus serves as its lower
guide. The upper end of the spindle is at the same time guided in a collar similarly fitted into the
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DRILLING-MACHINE
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upper branch of the bracket at a, and is thus guided vertically in ascending and descending. (In the
drawings it is shown at the lowest limit of its travel.)
To the top of the drill-spindle is attached the back-weight H by a jointed lever and guide link, which
embraces the top of the spindle and moves upon a vertical guide-rod, kept firm in its place by having
its lower end held by a screw-nut, in a socket cast in the bracket, in the manner of a bolt, a ruff forged
upon the lower end of the rod answering to the head of the bolt.
a
1122.
M
by
J
c
B
N
L
A
1130.
SCALE.-12 fect=7 inches.
The drill-spindle is itself screwed towards the middle of its length; it is there embraced by two
screw-wheels JJ between which it turns, and which serve the purpose of a nut to feed down the spindle
in the operation of drilling, by an arrangement which will presently be described.
K, is the table upon which the article to be bored rests, and to which it can be firmly held down and
adjusted by T-headed bolts and glands in the usual way, when thought necessary. The table, it will
be observed, is recessed and grooved to receive and retain the T-heads of the holding bolts, as fully
shown in the horizontal section, Fig. 1124, and the side view, Fig. 1125. When the article is much
smaller in area than the surface of the table, the fixing bolt-head can be entered at any convenient point
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DRILLING-MACHINE
of the surface by the recesses k h; and slid forward until it passes below the projecting ledges of the
recess, where it is retained.
The common mode of running two sets of inverted dovetail-grooves at right angles to each other,
lengthwise and across the table, seems, however, preferable to this mode of partially recessing the
surface.
The table is itself supported upon the sole of
the large carriage-bracket L, which is strength-
H
ened by two strong ribs cast on its under side.
This bracket is attached to the framing A A by
two pieces YY, which are bolted upon it and
planed true to the angle of the inverted bevel
edges of the broad face-rib of the main frame.
These edges are also planed where they meet
1123.
the oblique faces of the pieces YY. By this
means a joint is formed which allows of a sliding
motion vertically, but does not admit of any de-
viation laterally. When the slides become loose
G
by wearing of their surfaces, the pieces Y Y ad-
mit of being tightened by means of pinching
screws fitted against them through continuous
snugs cast on the bracket. This arrangement is
fully explained by Figs. 1124 and 1125.
This bracket is raised and depressed by means
of a hand-crank applied at u. Upon this spindle
is fixed the spur-pinion U, (shown in combination
by Figs. 1122 and 1123, and separately by Figs.
1132 and 1133.) This pinion geers with the
spur-wheel V, (partially seen in Figs. 1122 and
1123,) on the same spindle with the pinion W,
Fig. 1122, which geers in turn with the rack 10
set into the frame A A of the machine. so as to
form an integral part of it. By turning the hand-
G
crank on 26, it is thus manifest that the motion
will be transmitted to the bracket, which will
either be raised or lowered according as the crank
is turned in one direction or the other.
The table K has a double movement upon the
sole of the carriage-bracket; one movement is
Y
Y
circular and the other is in the direction of the
length of the table. The circular movement is
K
effected by means of the hand-crank P upon the
L
spindle y, carried in bearings formed on the box
R
X, which thus serves as a centre of rotation. On
the spindle y is formed a worm, which, geering
with the worm-wheel P on a stud projecting
downwards from the table K, conveys the motion
of the handle P to the table. This arrangement
is well shown separately by the plan Fig. 1127,
and the elevation Fig. 1126. This last corre-
sponds to the view given in Fig. 1123. Opposite
views of it are also given in Figs. 1122 and 1125,
the last on an enlarged scale.
It will be observed that the stud on which the
worm-wheel P is fixed, is cast hollow, and is
fitted into the table K by a key at o, shown in
Fig. 1124.
The lateral movement of the table is effected
by a different arrangement. A recess in the
1133.
1132.
form of a parallelogram is cast in the sole of the
1131.
carriage-bracket L, with projecting ribs ee on its
under side to serve the double purpose of giving
strength to the sole-plate and of forming guides
against which the cover of the travelling-box X
SCALE.-12 feet=7 inches.
may slide, the surfaces in contact being planed true for that purpose. The motion is communicated by
means of the handle q, (Figs. 1122 and 1123,) upon the spindle which carries the bevel-wheel Q, (seen
in Fig. 1123, and partially in Fig. 1122; also separately in Fig. 1131;) this spindle has its bearings
attached to the bracket L, and its wheel-geers with the equal wheel R upon the end of the screwed
spindle d, which has its bearings r also attached to the sole-plate of the carriage-bracket, and works in
a long nut or internal screw formed in the cover of the travelling-box X, (see Fig. 1123 for the general
arrangement, also Figs. 1125, 1127, and 1130.) By turning the handle q it is thus clear that the piece
which serves the purpose of a nut on the screw d, will be carried along in the direction of the length
of the screw; but the nut being attached to the table K, the whole will be moved simultaneously in
that direction.
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DRILLING-MACHINE.
389
By means of these two motions any point of the table K can be brought under the axis of the drill;
and by means of the vertical motion it can be placed at any convenient height.
The feed of the tool during the operation of boring is obtained, as before stated, by means of the two
screw-wheels J J, by an arrangement of parts which forms the chief novelty of this machine. On the
axes of these wheels are placed two pulleys, the circumferences of which are embraced by the friction
collars SS, (shown in combination in Figs. 1122 and 1123, and separately by Figs. 1128 and 1129.)
The bearings of the axis being at-
tached to the framing A A of the
1128.
machine, it is obvious that the ma-
chine being in motion, if the pulleys
@@@@
be prevented from revolving, the
wheels JJ will likewise remain at
1126.
rest; but the screwed part of the drill-
0
spindle revolving between them, they
P 1127.
S
will act as a stationary nut, and cause
the spindle to descend through a
space equal to one thread of its screw
during every revolution. Again, sup-
pose the pulleys and wheels free, the
screw of the spindle, instead of de-
X
P
scending will simply cause the wheels
JJ to revolve on their axes through
1129.
a space equal to one tooth during
every revolution of the screw. Now,
between these extremes any amount
of feed or downward motion of the
drill-spindle may be obtained by
1125.
K
simply retarding the motion of the
wheels, by means of the friction-col-
lars SS, which embrace the small
pulleys on their axes; for the fric-
tion of the collars being less than to
prevent entirely the motion of the
L
wheels, and, at the same time, greater
X
than to allow a tooth to pass during
a revolution of the spindle, a down-
P
y
ward motion of the spindle must
thus be produced equal to the re-
tardation of the pulleys produced by
1124.
the friction-collars. Thus, any degree
of feed can be produced at pleasure
by the contrivance of the friction-
collars shown separately in Figs.
1128 and 1129. These collars are
formed in two halves S and S, with
Y
L
bosses joining the segments, pair
k
k
and pair; these bosses are reverse
screwed internally, the thread of the
one to the right, and that of the other
A
to the left; and being placed on a rod
o
8 8 correspondingly screwed right and
left, they are made to approach or
recede according as this rod is turned
to the right or left, and to embrace
A
more or less closely the surface of
K
the pulleys upon which they are
Y
L
placed. This screwed rod is pro-
longed, and has a handle placed on
its under end, by which the required
b
k
degree of friction can be adjusted at
pleasure, (see Fig. 1123.) The fric-
tion-collars are lined with copper,
SCALE.-1 foot=1 inch.
-for the purpose of increasing the
friction; for it is manifestly of advantage to obtain as much friction on the pulleys as possible with the
least amount of pressure.
This arrangement has also the advantage of allowing the tool to be speedily withdrawn; for on
slacking the friction-collars the balance-weight H will raise the spindle in ordinary cases; and when the
tool has a hold in the hole which is being bored, the balance-weight can be assisted in its office by the
hand-wheel placed on the axis of one of the wheels J; the wheel and screw will thus for the time be
converted into a pinion and rack.
DRILLING-MACHINES. See BORING-TOOLS.
DRILLING-MAC-INE, Vertical. By W. A. BURKE, Lowell Machine-Shop. From the description
already given of V. nitworth's drilling-machine, it is neodless to enter minutely into a detailed descrip-
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890
DRILLING-MACHINE
tion of this very complete machine. Fig. 1134 is a front view of the machine. Fig. 1135 is a side ele-
vation in the plane of the axis of the driving-cone and work-table.
The frame of this machine is of iron, cast in one piece, having a broad base or sole-plate at the
bottom, by which it can be properly fastened to a stone or other suitable foundation.
Fig. 1185. N is the loose and fast driving-pulleys. D, on the same shaft, is a set of cone-pulleys
which communicate the power by a belt to a corresponding set of cone-pulleys. T, near the top of the
frame rr and hh, are geers for decreasing the motion of the drill, similar to the back geering of turn-
ing-lathes. Upon the shaft which carries the cone-pulleys T is a bevel geer, which drives another
bevel geer made fast on the spindle-tube B. This tube runs loose in gun-metal bearings, and carries
round the steel spindle to which the drilling-tool A is attached, by means of a long splice in the
spindle and a corresponding groove in the tube.
1134.
0
I
h
k
S
b
o
E
F
F
n
n
The machine IS adapted to feed the drill down by hand, or it can be made self-acting. When feeding
the drill by hand, by turning the hand-wheel a, Fig. 1134, motion is communicated through the
geer d to the geer f, which is fastened to a revolving nut which moves the feeding-screw up or down as
wanted. The screw is prevented from turning round by means of a coupling which connects the screw
to the spindle, and slides on a parallel rod lying back of the screw. When the feeding is to be self-
acting, the geer k, which is fastened to the tube B, drives the geer c, fastened on its shaft by a splice
and groove. This shaft admits a motion upward sufficient to raise the geer g on its upper end from
driving c. When the feeding is done by hand, this upward motion is produced by moving the handle b,
which is on the end of a bell-crank lever jointed to the end of the shaft. By means of friction-collars
each side of pinion-geer g, pressure to which is given by a small hand-wheel, the quantity of feed can
be raised 80 as to suit the size of the hole to be drilled. The circular table FF on which the work to be
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DRILLING-MACHINE
391
drilled is laid, is prevented from turning round by means of a stop which alides on a rib cast on the
frame. n n are handles projecting from a nut, which, on being turned, elevates or depresses the table
F as may be required. E, Fig. 1135, is the handle to the shipper.
C
1135.
h
T
B
r
h
b
a
m
E
A
F
F
m
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71.
SCALE.-2 fect=1 inch.
A machine of gigantic dimensions has been constructed by Nasmyth for the Great Western Steam-
Navigation Company.
In this machine, the entablature carrying the upper end of the boring-bar is supported on two
massive pillars of masonry, placed one on each side of the boring-bar. The feed motion of the cutters
18 novel and ingenious in the extreme; it consists, primarily, of an internal screwed collar fixed on the
upper surface of the entablature, and surrounding the boring-bar. A train of geering, terminating in a
pinion working into a rack running down the side of the boring-bar, is attached to the latter and revolves
with it. The first wheel of the train is a species of crown-wheel, its teeth being set at right angles to
its axis of motion; this geers with the internal threads of the screwed collar before-mentioned, 80 that
by this means the train is set in motion by the revolution of the bar, and the cutter-boss, which is
attached to the lower end of the rack, is raised and lowered at pleasure.
Mr. Walton, of Leeds, has introduced a highly effective boring-machine, with columnar framing intended
principally for boring the apertures in the tube-plates of locomotive-engines. The machine is capable
of drilling a series of parallel holes on a surface of five feet square, without refixing the object under
operations, the tool-holder and the table being moveable at right angles to each other. This boring-
machine may be considered as a magnified drill, as the spindle is fed longitudinally, no cutter-boss
being attached. The framing consists of two plain columns, coupled at the top by a suitable entabla-
ture, and carrying two other transverse beams for the support of the drill-spindle and driving-goer.
The self-feeding motion may be worked by hand.
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392
DRY-DOCK.
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DRY-DOCK, U. S., BROOKLYN. History of the Commencement and Progress of the U. S. Dry-Dock
at the Navy Yard, Brooklyn.
New York was originally selected in 1794, as one of the points for the establishment of a naval
depot.
In 1826, COL. LOAMMI BALDWIN, a civil engineer of great skill and science, examined the harbor
of New York, to ascertain the feasibility of constructing a dry-dock of sufficient size to receive a ship-
of-the-line.
Locations for a similar purpose were examined at Boston and Norfolk, which led to the commence-
ment of dry-docks at both of those places in 1832, and their completion in 1836.
In March, 1835, Congress authorized an examination for a site for a dry-dock at New York, and
appropriated $100,000 for commencing it.
In the following June, Col. Baldwin examined the vicinity of the Navy Yard, and reported very
favorably upon the facility for constructing such a work, nearly on the site where the present dock has
been built.
In March, 1841, Congress made an appropriation of $50,000 for commencing a dry-dock at New
York, and in August, EDWARD H. COURTENAY, professor of Civil Engineering at the National Academy
at West Point, was appointed chief engineer of the work.
Mr. Courtenay remained in charge of the work one year, during which time there was expended the
sum of $35,264.75 on the coffer-dam, and erecting workshops, and providing tools, &c., for carrying on
the work.
The succeeding Congress failed to make a further appropriation for the dock, and all operations were
suspended in August, 1842.
At the close of this session Congress appropriated $100,000 for the construction of a floating dry-
dock at New York, if the plan should be approved of by the Secretary of the Navy.
A commission was formed of naval officers and engineers, to investigate the merits of the different
plans of floating-docks, as compared with the walled stone-dock, and also to determine the best plan of
a floating-dock.
They reported in favor of the walled stone-dock as the best, and the balance" as the best of the
floating-docks.
In the naval appropriation bill of 1843, Congress directed an examination of a project for construct-
ing a dry-dock in the city of New York, on the plan of using the Croton water as an elevating power,
and an investigation of the best plan of a floating-dock.
W. P. S. SANGER, the Engineer of the Bureau of Yards and Docks, was directed to examine and re-
port on these subjects, which he did adversely to the project of using the Croton, and the "Sectional"
as the best plan of a floating-dock.
In February, 1844, Hon. HENRY C. MURPHY, a member of Congress from Kings Co., N. Y., took up
the subject with great interest and energy, and presented the matter to Congress in a very able
report.
To his exertions at this time may be mainly attributed a law that was passed in June following,
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DRY-DOCK.
393
directing a resumption of the work on the site and plan previously determined upon, appropriating the
unexpended balance of a former appropriation, amounting to $129,100.
In August, 1844, Gen. WM. GIBBS MONEIL, formerly an officer of the army, and then a distinguished
civil engineer, was appointed chief engineer, and the works were resumed in October following.
Under this gentleman's direction considerable progress was made in the construction of the coffer-
dam, and the removal of the excavation, and in preparing the plans and arrangements for conducting
the work.
In March, 1845, Congress appropriated $150,000 for continuing the work, and it was placed under the
direction of the Engineer of the Bureau, MR. SANGER, until February, 1846, when WM. J. MCALPINE
was appointed engineer in chief.
Congress has made the following appropriations :-
March, 1835
$100,000
Do.
1841
50,000
Do.
1845
150,000
August, 1846
250,000
March, 1847
275,000
July,
1848
350,000
March, 1849
490,000
Total,
$1,665,000
The progress of the work has been much retarded in consequence of the frequency with which its
officers have been changed.
In 1835, Col. Baldwin expended the sum of $5,000. From August, 1841, to August, 1842, Mr. Courtenay
expended $35,264.75 From August, 1844, to March, 1845, Gen. McNeil expended $114,675.83. From
March, 1845, to February, 1846, Mr. Sanger expended $115,951.81 and from February, 1846, to the
present date, (October 1st, 1849,) Mr. McAlpine has expended $1,147,310.39-making the whole
amount of expenditure $1,418,198.78; and contracts have been made amounting to about $250,000
more.
A description of the LOCATION and CONSTRUCTION of the Dry-Dock.-The dry or graving dock is a
walled basin sunk below the level of the sea, to allow vessels to float in and remain while undergoing
repairs. The water is removed from the basin, and the vessel is supported by shores resting on the
bottom and sides.
In many parts of the world the rise and fall of the tide is sufficient to allow the vessels to float in at
high, and become dry at low tide. When the tide is not sufficient for this purpose, it is necessary to
remove the water by pumping.
The tide in the harbor of New York rises four feet seven and a half inches above mean low-water.
The highest tides during the heaviest gales do not exceed eight feet above this mark, and the greatest
range between low and high tide does not exceed ten feet.
The government dock-yard occupies the Wallabout bay, an arm of the East River, between the
cities of Brooklyn and Williamsburg, on Long Island, and directly opposite the private dock-yards in
the city of New York. The bay forms a fine harbor of sufficient capacity and depth of water to
receive a large navy.
The dry-dock which is just being finished, and which it is now proposed to describe, is situated on
the convex side of the channel of the Wallabout, near the northwest corner of the Navy Yard. It has
been chiefly excavated, but the lower end of the dock was built on the edge of the channel.
This part of Long Island is a diluvial formation, composed of a coarse, sharp, red, and yellow sand
and gravel, interspersed with boulders of trap and greenstone rock, some of which are of an enormous
size, and will weigh several thousand tons.
The site selected for the dock is of more recent formation. The superstratum is formed chiefly by
vegetable decomposition; below this, for a depth exceeding one hundred feet below tide, is a quick-
sand formed by the debris of the rocks in the vicinity, brought down and deposited with alluvial matter
by the East River, which at this place is expanded to three times the width it has above and below,
and the velocity of the water correspondingly reduced.
This material is an almost impalpable sand, containing a large proportion of mica. When confined and
undisturbed, and not mixed with water, it is very firm and unyielding, and presents a strong resistance
to penetration. When saturated with water, it becomes a semi-fluid, and is moved by the slightest
current of water passing over or through it.
Borings were made to a depth of sixty feet below the level of the foundation, and the same material
was found to extend to that depth. Small veins of coarse sand were occasionally encountered, through
which flowed springs of fresh water.
It was on this material that the coffer-dam was to be constructed, to exclude the tide-waters, and a
foundation prepared to sustain the enormous weight of the superstructure.
The work will now be described under the following general heads, viz:-
Dimensions of the structure
The gates.
The coffer-dam.
The pumping engines.
The earth-work.
The pump-well, culverts, and engine-house.
The bottom springs.
The machine and tools used ; and
The foundation, apron, and pile-driving.
The cost of the work.
The masonry.
Dimensions of the Structure.-The pit which was excavated covered an area of over two acres at
the top, and over one acre at the bottom. It was sunk about forty-two feet below the surface of the
ground, and thirty-seven feet below mean high-water.
50
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The coffer-dam in front was four hundred and seventy feet long, and from sixty to one hundred feet
wide. The wings were one hundred and seventy-five feet long, and from fifteen to thirty feet wide.
A double row of sheet piling protection-timbers were extended entirely around that part of the pit
which was not protected by the coffer-dam.
The foundation is three hundred and ninety-two feet long, and one hundred and sixteen feet
wide.
The main chamber is two hundred and eighty-six feet long, and thirty feet wide on the bottom, and
three hundred and seven feet long, and ninety-eight feet wide on the top; and by using the floating-gate
instead of the folding-gates, an additional length of fifty-two feet may be obtained. The least width
is at the hollow quoine, where the walls are sixty-six feet apart at mean high-water line. The least
depth of the dock is over the mitre-sills, where there is twenty-six feet of water at mean high-tide.
The whole height of the walls is thirty-six feet.
The Coffer-Dam-Before the excavation could be extended below the surface of the water of the
bay, it was necessary to exclude the tide, and to provide for the removal of the water which would
collect in the pit.
As the excavation was required to be carried to a great depth, (thirty-seven feet below mean high-
tide,) it became necessary to provide a strong and tight barrier to resist the pressure and percolations
of the tide-water.
The original dam was built as follows:-
Three rows of contiguous square piles were driven entirely around the lower end of the proposed
excavation, leaving two intervals of ten and twelve feet between them. These piles were secured at
the top, and at the level of low-water, by horizontal wales and iron tie-bolts.
The dams were filled with the silt which was taken from the excavation.
The piles were of yellow-pine timber, thirty-five to forty feet long, fifteen inches square, and sawed
to parallel sides. A portion were tongued and grooved but on examination it was found that from the
difficulty experienced in driving, the piles swerved aside, and fractured or drew out from the tongues.
The wales were of oak, twelve inches square, bolted once in ten feet, with bolts two inches in
diameter.
On the first trial of this dam, (in February, 1846,) it was forced inwards by a pressure of less than
ten feet head of water, and by the time the excavation was taken down, so as to bring a head of thirty
feet of water against the dam, the water of the bay forced its way through the sand beneath the piles,
and burst into, and filled the pit.
This breach occurred in July, 1846, at the northeast angle of the dam. It was repaired, and in
September following, a similar breach occurred at the northwest angle of the dam.
The first breach occurred without warning, after the workmen had left. The first indication of the
September breach, was an increased flow of water in one of the bottom springs, which was situated
fifty feet from the nearest part of the coffer-dam.
The water flowing from this spring had previously been fresh; it was observed to change alternately
from fresh to salt, several times within a few minutes, and in less than an hour had increased to five times
its former quantity, and soon after brought up volumes of the black mud which overlays the quicksand
in the channel of the bay. The direction of the breach was soon developed by the sinking of the
coffer-dam, some of the piles in which settled down vertically from five to six feet.
After the occurrence of these breaches, it became necessary to reconstruct a dam.
This was done with piles from ten to fifteen feet longer than had been before used. The new dam
which was placed on the outside of the old one, was made from thirty to forty feet wide, so that the
weight of the earth would break down into any passages which the water might form through the
loose soil on which the dam rested.
In the narrow dams it was found that the earth adhered to the timber on the sides, and that the
cavities formed by the filtering of the water, became very large before any of the earth broke down
to fill them.
The new dam was filled with gravel, containing loam, sand, and coarse stone. The gravel was filled
in water thirty feet deep, and to prevent the stone from separating from the other materials in the
descent, it was discharged in large quantities from boats with drop bottoms which contained one
hundred tons. A row of piles was driven on the inside of the original dam, to a depth from twelve
to fifteen feet below the proposed level of the foundation. A heavy bank of coarse gravel was filled
on the inside of the dam, extending up to the lines of the foundation.
The material on which the dam rested, was so unstable, that although the piles penetrated it from
fifteen to twenty-five feet, yet the dam continued to yield to the pressure, and was only sustained by
the closest watchfulness, and the most prompt application of remedies.
As long as the excavation was in progress, there was no opportunity to obtain any support from the
inside, and whenever it could be done, chain cables were attached to the dam, and secured to mooring
blocks on the shore. These cables, made of iron two inches in diameter, were repeatedly broken. On
one occasion six of them broke during one night.
The removal of the excavation adjoining the dam was not effected any faster than it could be fol-
lowed up by the foundation piling, and this was done in trenches, leaving abutments of earth on each
side. Timber shores were extended from the foundation to the dam, before the intermediate sections
of earth were removed.
In like manner the rear work of the masonry on the foundation was at first laid in sections, and
braces extended from it to secure the dam.
The thrust upon these braces at one time was 80 great, that it moved a mass of masonry exceeding
two hundred and fifty tons weight.
The earth in the dam was subject to a continued waste on the side adjoining the bay, by the action
Digitized by
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of the water flowing through the joints of the piling but this waste gradually decreased, until it be-
came of but little importance.
The whole number of piles driven for the coffer-dam is 3,504.
Earth Work.-That part of the excavation of the pit which was above the level of low-water was
taken out before the coffer-dam was constructed. There was also about ten feet of the earth below
the water dredged. The semi-fluid state in which the material was found after the water had been
pumped out of the pit, rendered its removal very difficult and tedious.
When the excavation had been extended to a depth within about six feet of the level proposed for
the foundation, springs of fresh water burst up through the crust, and discharged very copiously.
It was found necessary to use tight vessels in removing the earth, because when the water mixed
with the sand, it became 80 fluid, that it would escape almost wherever water would flow. Boom
derricks were used to some extent in the removal of the excavation from the pit. Dumping tubs were
suspended from the end of the boom, which, when filled, were hoisted to the level of the ground by
steam-power. The chief part of the excavation, however, was taken out in cars, which, when loaded,
were hauled up the inclined planes by steam-power. These cars possess an advantage over the earth-
cars commonly used for this purpose, as they were hung very low, not above thirty inches from the
top of the ground to the top of the box. This saves the labor of shovelling the earth twice to load
the cars. They dumped between the axles and between the rails.
The walls were backed up with gravel, as fast as the masonry was laid.
Puddle walls were extended from the sides of the masonry to cut off the passage of water along
the walls.
The Bottom Springs.-These were met with, as before stated, when the excavation had nearly reached
the level proposed for the foundation, and were the cause of the greatest difficulty which was encountered
in laying down the foundation.
The water which flowed from them was entirely fresh, and evidently came from a source higher
than the tide-water. The temperature was 58° in January, and 55° in August. The temperature of
the water in the bay at the same time was 43° and 46°, and that of the atmosphere was 40° and 90° at
the same dates. The flow was not affected by the rise and fall of the tides.
The strata through which the springs flowed, were evidently at a great depth (not less than thirty
feet) below the foundation, and the veins of water of the different springs, even those contiguous, had
no connection with each other.
The difficulties caused by these springs did not proceed from the mere flowing of the water; but
this, as it came up, brought with it large quantities of sand, so fine and impalpable, that it would in-
sinuate itself through the smallest interstices, and if allowed to flow in this manner, would soon have
endangered the surrounding works. Nor could the water be checked with safety, as the pressure was
sufficient to raise the foundation, however heavily it could be loaded. It became necessary, therefore,
to provide for the flow of the water, and at the same time check the removal of the sand.
After repeated trials, it was found that the level of the outlet of the springs could be raised to a
height which would not disturb the foundation, and would yet be sufficient to check the velocity of the
water so much, that it would not disturb the sand through which it flowed.
The largest spring discharged (in 1848) ten gallons per minute. When the water was allowed to
flow at a level, twenty-six feet below low-water, it discharged thirty-eight gallons per minute, which
contained twenty-seven ounces of fine sand at a level twenty-two feet below it discharged thirty-
three gallons, containing seventeen ounces of sand; at a level nineteen feet below, it discharged twenty-
two gallons, containing four ounces of sand; and at a level seventeen feet below low-water, the water
flowed unmixed with sand.
One of the most troublesome and refractory springs was encountered at, and near the pump-well, at
the northeast corner of the dock.
The first evidence of its effect was the undermining and settling of the piles driven to support the
pumps and engine, and rendered it necessary to change the pump-well; but the spring followed, and
compelled another change of the well. The spring was driven out of the old well by filling it with
piles, but it immediately burst up among the foundation piles of the dock near by. In a single day
it made a cavity in which a pole was run down to the depth of fifteen or twenty feet below the
foundation; one hundred and fifty cubic feet of cobble-stone were thrown into this hole, which settled
ten feet through the night, and fifty cubic feet were thrown in the following day, which drove the
spring to another place, where it undermined and burst up through a body of concrete two feet thick.
This new cavity was repeatedly filled with concrete, leaving a tube for the water to flow through,
but in a few days it burst up in a new place, where it soon undermined the concrete, and even the
foundation piles, so that they settled from one to three inches. These piles were thirty-three feet
long, and had been well driven by an average of seventy-six blows from a bammer weighing two
thousand two hundred pounds, falling thirty-five feet at the last blow, which did not move the pile over
half an inch.
These alarming results rendered paramount the adoption of the most thorough and speedy measures
to prevent any further injury from this source. Accordingly, as many additional piles as could then be
put in the space were driven, and those put in before were then driven from eight to twelve feet
lower, by means of followers. The old concrete was removed to a depth twenty inches below the
top of the piles. An area of about one thousand square feet around the spring was planked a
floor of brick was laid in dry cement; and on that another, also of brick, was set in mortar, made
of Roman cement; the space was next filled with concrete, and the foundation completed over all
in the usual manner, and with the greatest dispatch. Several vent-holes were left through the floors
and foundation. After a few days' interval, when the cement had become well set, the spring was
forced up about ten feet, at which level it ever after ran clear, and without discharging sand, and
gave no further trouble.
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The other bottom springs, some forty in number, have been of a like character, but the successful
result obtained in the treatment of that above described, led to the adoption of the same plan with
each, and with similar results.
Two of the springs were accidentally closed by freezing in 1848, and forced up, in one case eight
hundred, and in the other twelve hundred square feet of the foundation. The rising took place between
the lower timbers and the planking, lifting also the first course of the stone floor, which was from
twelve to fifteen inches thick.
None of the springs were closed until the inverted arches of masonry and side walls had been laid,
and the cement had become well set. The pressure on the bottom of the floor is 80 great that the
water sweated through the joints, but did not disturb the stone.
The arrangement proposed to be accomplished, was to bring up all of the springs through the foun-
dation, and have no pressure upon it, until the masonry was laid, and the cement had become well set;
but there were many minute veins of water that were unnoticed when the foundation was laid, which
exerted a force upon the cement jointe, and rendered its setting very slow and tedious. These joints
will require a twelvemonth or more to become impervious to the water.
The whole amount of water which came into the pit for the last year was from these springs; none
leaked through the dam. The quantity which flowed in was seven hundred cubic feet per hour.
The water was removed from the pit by a steam-engine of twenty-five horse power, driving two
plunger pumps of fifteen inches diameter, and five feet stroke, which discharged six hundred cubic
feet per minute.
Foundation, Apron, and Pile-Driving.-In 1835, Col. Baldwin examined the proposed site of the
dock by borings, which he extended in several places to a depth exceeding eighty feet below tide.
These borings brought up sand and clay, and also fresh water, but touched no rock.
Col. Baldwin remarks, Upon careful examination of these circumstances, I have no doubt a dry-dock
may be safely founded at Wallabout bay. Should piling for the foundation be thought necessary,
which can best be determined in the process of excavating, the piles cannot be driven deep in such soil,
and will have similar or better resisting materials than those hitherto used The construction of a
dock in the yard, however, will be more difficult than either of those built before, (at Charleston and
Norfolk.")
In 1842, Mr. Courtenay commenced driving the piles for the coffer-dam, and remarks, During the
progress of the work we were enabled to form a very satisfactory opinion, as to the character of the
soil upon which the dock was to have been founded, and the frequent examinations then made resulted
in the conviction, not only that the substratum was sufficiently firm to resist, without danger, the pressure
arising from the weight of the contemplated structure, but that the nature of the soil was far better
adapted than had been supposed, to resist the percolation of water through the dam."
A deposite of clay mixed with a large proportion of very fine sand, which covered the northeast
portion of the pit, for several feet in depth, probably led to the favorable conclusions of these gentle-
men.
The soil, as was developed by the excavation, is as has been previously described, and there is but a
very small portion of clay in any part of it.
The borings which were made during the progress of the work extended to a depth forty feet below
the foundation. Specimens have been preserved of the soil taken from various parts of the dock, and
at every change in depth, including that which was brought up by the borings. Sets of these specimens
have been deposited in various public institutions through the country.
A trial-pile was driven in June, 1846, to the depth of forty-five feet below the foundation. It was a
round stick of spruce, twenty inches diameter at one end, and fourteen at the other, and forty-nine
feet long. It was shod with iron, and was driven by a hammer weighing two thousand and twenty-
four pounds, falling from its greatest elevation, thirty-five feet.
For the first hundred blows the hammer fell but a few inches; the next two hundred and sixty blows
drove the pile thirty inches in forty-six minutes; the next two hundred and sixty-five blows occu-
pied an hour, and drove the pile from half an inch to one and a half inches at each blow; the next
one hundred and ten blows in an hour, averaged one and a quarter inches at each blow, the hammer
falling at the last blow thirty-four feet. The pile subsequently received about two hundred blows
through the medium of a follower, which drove it an average of half an inch to each blow.
In June, 1847, a pile was driven forty-three feet by Nasmyth's steam pile-driver and then another pile
fifteen feet long, driven on top of the first, making a total depth driven into the earth of about fifty-
seven feet.
The first pile was driven forty-two feet, by three hundred and seventy-three blows in seven minutes,
as follows: Four blows, four inches each eight blows, three and a half inches each twenty-two blows,
three inches each twenty-five blows, two inches each; forty blows, one and three quarters inches
each; fifty-six blows, one and a half inches each; thirty-two blows, one and a quarter inches each
sixty-four blows, one and an eighth inches each; seventy-three blows, one inch each; the last forty-
nine blows, half an inch each blow.
The second pile was driven fifteen feet by two thousand four hundred blows in forty-three minutes,
as follows: Thirty-three blows, three-eighths of an inch at each blow seventy-three blows, one-fourth
of an inch each; one hundred blows, one-eighth of an inch each eight hundred blows drove it together
eighty-eight inches; three hundred blows, twenty-four inches; three hundred blows, twelve inches;
four hundred and fifty blows, eleven inches, and the last three hundred and forty blows together drove
the pile five and a half inches.
The movements of these piles indicated the continuance of the same material to the depth which
they reached and the uniformly increasing resistance, as the pile penetrated the earth, gives very
favorable evidence of the support which the piles afford, when they are thus driven to the point of
absolute resistance.
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The soil required very hard driving to force the pile into it, and as long as the material was undis-
turbed, the subsidence of the sand around it added greatly to the firmness of the foundation. Yet
the springs were liable to disturb and loosen the soil around the piles, and, as has been previously
stated, destroy their value as supports.
To prevent the wasting effects of the springs, it became necessary to put down the foundation in
small detached pieces, and frequently to drive the piles at a level, sometimes to the extent of six feet
above the proper plane. When one of these pieces was taken in hand, the earth was removed, and
the concrete, timber, &c., put in without a moment's cessation; for the springs would in a few hours
render the earth semi-fluid, which had before been compressed to great firmness by the insertion of the
piles.
It was originally supposed that piles driven at distances of three feet from centre to centre, and
twenty to twenty-five feet long, would afford a sufficient foundation to the superstructure; but from the
fear that changes might take place after the foundation was put down, it was determined to drive as
many piles as could be forced into the earth. The chief part of the piles were driven to the point of
absolute resistance, and whenever a hammer of two thousand pounds weight, falling thirty-five feet,
drove the pile for the last few blows exceeding three inches per blow, another and longer pile was
driven alongside.
Great care was taken in registering the performance of all the piling engines used in constructing
the foundation of the dock the depth driven by every blow that has been given to every pile was
recorded, and from these data the following averages have been made. The average number of blows
received by the piles was seventy-three the average depth driven by the first five blows is eight
inches each; by the middle five blows, six inches each; and by the last five blows, one inch each
blow.
The whole number of bearing-piles in the foundation is 6,539, besides 1,744 sheeting-piles, which
serve also as bearing-piles. The piles are chiefly round spruce timber, from twenty-five to forty-five
feet long, averaging fourteen inches diameter at the head. The average length of the piles as driven,
is thirty-two feet.
The sheeting-piles were yellow-pine planks, five inches thick, and from twelve to twenty-five feet
long. They averaged fifteen and a quarter feet long. They were tongued and grooved, and were driven
entirely around the foundation, and four rows across the pit.
The piles were protected at the head by a band of wrought-iron, three by one inch, made of the
toughest iron that could be procured. One ring would generally drive two piles before it burst, and
by welding it could be used three times. Occasionally the point was shod with iron, but this did not
increase the facility of driving, as the resistance was caused by the friction on the sides of the pile.
The hammers which were used were generally about twenty-two hundred pounds weight. Several
were used from three thousand to four thousand five hundred pounds, with economy and effect. The
larger hammer did not injure the pile as much, and it was driven in less time, and with a less
number of blows, and the same power as was applied to the smaller hammer.
The leaders of the machines were from thirty-five to fifty feet long.
The hammers were hoisted by men working with a crank, and on a treadwheel, and with horses,
but chiefly by steam-power. The expense of these several methods of driving piles are in the order
in which they have been stated above.
A contract was made for the use of one of Nasmyth's steam pile-drivers, and one of his best
machines was imported. Unfortunately, however, the machine was constructed too light to perform the
severe labor to which it was here subjected.
When in order, it produced the most astonishing results-driving the piles in less than one-third the
time or expense of any other known method.
Its principle consisted in very rapid short blows, with a very heavy hammer. The steam cylinder
was inverted over the hammer, to which it was connected directly by the piston-rod; and the hammer,
which weighed two and a half tons, was hoisted by the stroke of the engine at every revolution. Both
the cylinder and the hammer, were supported by the pile itself, to which it was loosely attached by a
deep cap or band. The cylinder moved up and down, alongside a spar, and the steam was conveyed
to it by a flexible tube leading from the boiler on the frame below. The hammer made about sixty
blows per minute.
The concrete masonry which was used in the foundation was made as follows:
A soft mortar was made of one part of hydraulic cement, and two parts of clean sharp sand into
this was thrown five parts of stone, broken, not to exceed one and a half inches in diameter. The
mass was thoroughly mixed, and immediately thrown into the place where it was required for use.
The foundation was put down in the following manner:
The bearing-piles were sawed off at a level thirty-three and a half feet below mean high tide. The
earth was removed to a depth two and a half feet lower, which space was filled with concrete
masoury.
The piles were capped with yellow-pine timber, twelve by fifteen inches scantling, trenailed and
bolted to the piles, and laid transversely to the axis of the dock. The spaces between the timbers
were filled with concrete. Yellow-pine plank three inches thick were jointed, and closely laid on and
spiked to the timbers. On the top of the plank another set of timbers of the same size were laid,
breaking joints with those below. The spaces were filled with concrete, and covered with plank in
the same manner as the first floor.
At the foot of the dock an apron is extended for thirty feet in front, to protect the lower end of the
foundation from undermining.
It is composed of timber and plank, and supported on piles, with concrete masonry between and
below the timbers, in the same manner as the foundation of the dock. It is prevented from floating by
trenailing and bolting to the piles, and by inserting dovetailed stone between the ranges of timbers.
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The tide tables which had been kept for several years at this station, showed that the level of
the foundation should be placed six inches lower than had at first been supposed to be necessary.
It was accordingly assumed at a level which would give twenty-five feet of water on the mitre-sills
at high tide, for two-thirds of the days in the year.
The Masonry.-It is believed that no modern structure in the world surpasses this, in the size of the
stone, in the accuracy of their workmanship, and their durability.
The quantity of masonry which has been laid to form the walls of the dock is 23,375 cubic yards,
and in the draining and discharging culverts, and the engine-house, and other masonry connected with
the dock, there is 5,250 cubic yards.
All of the facing-stone has come from the Sullivan and Frankfort quarries in Maine, and New Lon-
don in Connecticut.
The interior stone was chiefly obtained from the Staten Island and the Highland quarries in New York.
A system of inverted arches occupies the whole extent of the lower part of the structure, and serves
not only to distribute the weight of the walls over the whole surface of the foundation, but to resist
the immense hydraulic pressure from beneath. The floor of the main chamber is first formed of a
tapering course of cut-stone, twenty-seven inches thick at the head, and twelve inches thick at near
the mitre-sill; the second course of stone is uniformly three feet thick, and the arches are extended to
a height nine feet above the floor on each side. The floor of other parts of the dock is made in a
similar manner.
The mitre-sills are immense blocks of granite; the key-stone is estimated to have weighed about
fifty tons before it was cut; its weight is now 43,300 pounds; sixteen similar stones form the mitre-
sills, and the smallest stone weighs 13,300 pounds.
The floor of the chamber is level on the bottom for thirty feet wide, and the sides are carried up in
steps or altars for the convenience of shoreing the vessel and working under her bottom, as represented
in Fig. 1136, where the Ohio, ship-of-the-line, is shown in dock," sustained by the keel-blocks and
shores.
The side walls are laid up with English bond, alternate courses of stretchers and headers the stones
in the alternate courses are of the same length which gives what is termed 'plumb-bond," although
the stones in the same course differ in length, a variety of lengths having been previously determined
upon to facilitate the quarrying of the stone. These lengths have, however, been 80 arranged as that
adjoining stone do not differ to exceed three inches, and increase and diminish gradually from the
shortest to the longest stone. The difference in length is therefore imperceptible.
The courses are chiefly twenty-four inches thick, a few near the bottom being twenty-seven inches
thick. The beds of the stone in the stretcher courses are from three to three and a half feet broad.
and in the header courses are from four to five feet broad. The length of the headers is from three to
four feet, and of the stretchers from six to eight feet. The headers are in all cases one-half of the
length of the stretchers.
The smallest stone in the face exceeds three thousand pounds, and the average is about six thousand
pounds. Many of the coping and other large stones exceed fifteen thousand pounds. The interior
stones are also large, and will average upwards of fifteen hundred pounds.
The facing stones are all laid to a joint not exceeding three-sixteenths of an inch, and the joints are
kept up full to the lines for the full depth of the stone.
The facing stones have been backed up with a course of scabbled stone cut to the same thickness, and
laid to joints not exceeding half an inch.
The interior and rear of the wall has been laid up with coursed rubble, which has been so selected
that either one or two courses made up the thickness of the facing course.
The following extract is taken from the contract for the granite facing:
" All of the stone must be of the most durable description of granite, entirely free from sap, stains,
or seams, and obtained from quarries which may be approved of, by the Engineer in charge of the
work; all of the stone which show in the chamber must be of the same color and general appearance.
" Patterns for quarrying and cutting the stone will be furnished by the government; on all
the arch-stones full corners and edges will be required on the back lines of the stone; all of the stone
will be delivered cut, except such stone as may be directed to be delivered unwrought, in which case
they shall be quarried out without any unnecessary excess of stone, but of sufficient size to fill the
patterns. The cut-stone designed for the facing of the work must be delivered with perfect edges on
the show-lines, and none will be received which are in any way marred or nicked.
The stone must be delivered in the order in which they are required for use, as far as practicable.
" In the courses of the chamber above the inverted arch, and in the other walls where an additional
width of bed is permitted, the minimum size will be given in the bills, but stone of greater width will
be received.
Suitable 'lewis' holes shall be drilled in the bed, or such other surface as may be directed, to receive
a lewis of sufficient size to suspend the stone with safety.
Such cranes, machinery, and assistance as may be required for discharging the stone from the vessels
at the Navy Yard, will be furnished by the government.
" The cutting which is required to be done on the face of the stone which shows, and also on the builds
of the outer stone, shall be as hereinafter described as first-class work; that required on the beds, builds,
and joints, shall be as hereinafter described as second-class work; that required on the rear of the front
and interior stone, shall be as hereinafter described as third-class work. The beds and joints must
be dressed up full to the square, and no slack joints will in any case be permitted. The cutting will be
required to be done in the following manner, to wit:
" First-class work.-The arris must be kept clean and sharp, with fine-cut drafts run around the sur-
faces to be dressed. Within these lines the surfaces must be taken down fair and even with a patent
hammer of eight plates. No holes or depressions of any kind that will show in the face will be per-
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mitted; and the dressing with the hammer must be level and square, 80 as to present a smooth fair
appearance.
44 Second-class work.-A good arris must be kept; clean draft-lines must be run around the surfaces to
be dressed. Within these lines the stone must be dressed down to a fair even level surface, with a
common pean hammer. No depressions of any kind will be allowed within six inches of the face; none
which exceed six inches in diameter, or one inch in depth, or where they shall together exceed one-
fourth of the surface in which they occur.
" Third-class work-Draft-lines shall be run around the surfaces to be dressed. Within these lines,
they shall be pointed down to a fair even surface and finished with a pean hammer, 80 as to make good
close work, of not exceeding half an inch joint. No cavities or depressions will be allowed which exceed
eight inches in diameter, or one and one-half inches in depth, or when they shall together exceed one-
fourth of the surface in which they occur."
The following extract is taken from the contract for the backing-stone.
"They shall be of a sound durable description of granite or gneiss, free from sap or seams, split out
by wedges in blocks, with parallel beds and sides; at least three-fourths of the bed, and one-half of the
build, must have a fair level bearing-surface; the vertical joints must be split down at right angles to
the bearing surface of the stone; the stone must all be drilled on the top bed to receive a lewis of such
size and form as shall be directed. The dimensions of the stone must in no case be less than the fol-
lowing viz., length, two and one-half feet; width, one and one-half feet; thickness, eight inches. and
no stone larger than the following will be received viz, length, eight feet; width, four feet; thickness,
two feet and the stone must average not less than twelve cubic feet."
The whole of the masonry was laid in mortar made of one part of Hydraulic cement and two parts of
clean sharp sand; the cement used was from the celebrated Lawrence and Newark" manufactories,
at Rosendale, New York.
It was required to be fresh ground, very fine and lively, and transported under cover in barrels, con-
taining about three hundred pounds; the barrels to be made of seasoned air-tight staves. and to have
twelve hickory hoops, and each barrel to be well papered. Every tenth cask was subjected to the
following tests: first, mixed up in flat cakes of two inches diameter, the moisture carefully dried from
the surface by means of blotting paper, until it was set enough to bear one-fourth of a pound
weight on a wire of one-twelfth of an inch diameter, and then put in water, where, after the lapse
of not exceeding five minutes, it should bear one pound on a wire of one-twenty-fourth of an inch
diameter.
Second, a similar-sized cake, after the lapse of five days' insertion in water, was required to bear a
wire of one-twenty-fourth of an inch, loaded with fifty pounds.
Third, two bricks united by cement and put in water five days, must resist one hundred pounds before
separating.
No cement was used until after it had stood the above tests. They were made with water at a tem-
perature of 70°. The mean of a large number of these tests is as follows:
The time to dry in air, to bear one-fourth pound on a wire one-twelfth inch diameter, was 8 minutes.
The time to set in water, to bear one pound on a wire one-twenty-fourth inch diameter, was three and
one-fifth minutes.
Force required to thrust a wire one-twenty-fourth inch diameter, through cakes of cement two inches
diameter, and three-fourths of an inch thick, after being immersed in water 24 hours, 65 pounds.
do.
do.
48
"
70
"
do.
do.
72
"
75
"
do.
do.
15 days, 155
"
do.
do.
50
"
390
"
The joints of the whole masonry have been pointed up in the following manner Cement and sand
were put in an iron mortar slightly moist and made nearly into an impalpable powder; this was driven
into the joint to the depth of an inch by an iron caulking tool, and the upper surface rubbed with a steel
tool until it became very hard; in a few days this pointing was nearly as hard as the adjoining stones.
The masonry of the dock was laid up in an unprecedented short time. The first stone was laid
May 12, 1847, but the foundation was not entirely completed until June, 1848. The first coping-stone
was laid July 4, 1849, and the whole work completed during that season. This dispatch was owing
to the systematic arrangements of the vàrious operations, and to the number and capacity of the
machines used in the construction. On the completion of the work it was found that there were no
stone left on hand.
The prices which have been paid for the stone used in this work are as follows:
For the granite coping, hollow quoins, and other expensive stone, sixteen dollars per cubic yard.
For the plain facing-stone, ten dollars; for the second class, nine dollars; and for the rubble stone, five
dollars per cubic yard. For the fine cutting on the hollow quoins, checks, etc., one dollar per super-
ficial foot: on the facing stone, forty cents; for the second class of cutting on the beds and joints of the
facing stone, twenty cents; and for the third class of dressing on the interior stone, twelve cents per
superficial foot.
The weight of a cubic foot of the several kinds of granite, sienite, and gneiss, used on this work is as
follows: Sullivan, Frankfort, and Seal Harbor, 168 pounds; Blue Hill, 165; Quincy, 169; Millstone
Point, 170; Breakneck, 169; Staten Island, 186; and Kips' Bay, 172.
The Gates.-The folding gates are similar to those used in canal locks, though of much greater dimen-
sions. Such gates have usually been built of wood, though a few docks in Great Britain have them
made with cast-iron frames, and covered with oak or sheet-iron.
The low temperature of the atmosphere in this climate renders the use of cast-iron dangerous where
it is subject to violent concussions; to avoid this objection, Mr. McAlpine was induced to arrange a gate
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made of wrought-iron, on an entirely original plan; they are the first iron gates which have been built
in this country. They are made as follows:
Two leaves are to be erected 80 as to turn on the quoin posts, and secured to the masonry of the
dock by steps and straps, and arranged to be worked by capstans in the walls, from which chains are
extended to open and close the gates.
The frame of each leaf is composed of a series of horizontal curved bars of wrought-iron, bolted to the
quoin and mitre posts, and covered on the outer side by a sheathing of boiler-plate, riveted and secured
together by angle-iron.
The outer extremity of each leaf is supported by two rollers traversing on circular tram-plates, laid
on and secured to the floor of the masonry.
The quoin-post is a cylinder of cast-iron. The mitre-post is made of wrought-iron, and a buffer of
oak inserted where the two leaves come in contact. A similar buffer is inserted at the bottom of each
gate where it comes in contact with the mitre-silla.
There are two valves in each leaf for the passage of water to and from the chamber of the dock.
Each leaf is thirty-eight feet three inches long, and thirty-one feet high, curved on a radius of seventy-
six feet seven inches on the outside of the gate. The gate is twenty-six inches wide at the quoin-post,
and twenty-two inches wide at the mitre-post. The quoin-post is turned and planed to fit the quoins
and collar-straps.
The horizontal bars are made of plates of wrought-iron, twenty-two inches wide and three-fourths of
an inch thick, curved to suit the form of the gate, and made up alternately of three and four plates to
each bar, and secured at the joints by splicing-plates.
The sheathing is made of boiler-plates, from ten to fourteen feet long, and two to four feet wide.
The bottom courses are five-eighths of an inch thick, and they gradually decrease in thickness, and are
one-quarter of an inch thick at the top of the gate; they are secured to the horizontal plates by means
of angle-iron riveted to each. The horizontal joints are lapped, and the vertical joints are butted, and
riveted, and chipped, and caulked, so as to be water-tight.
The mitre-post is made up of a plate of iron (welded) thirty-one feet long, twenty-two inches wide
and one inch thick, set upright, with side pieces secured by angle-iron; the whole secured to the hori
sontal bare by shelf pieces of angle-iron.
The valves are made of cast-iron and set in a cast-iron frame, bolted to the bars of the gate. The
valves are opened by screws placed on top of the gate.
The rollers are of cast-iron, eighteen inches in diameter, and set in a frame with a long rod and screw,
by means of which the extremity of the gate may be raised at pleasure. On the top of the gate is
placed a foot-walk, supported by iron bars, and a hand-rail of wrought-iron.
The capstans are geered, and the chain drum is provided with an ingenious arrangement for laying
the chains which are extended to open and shut the gates.
India Rubber is inserted in the buffers.
The whole surface of the gates is painted, to protect it from corrosion.
The horizontal bars were originally designed to be welded in one bar and to be made of iron one inch
thick, and the bars at the bottom of the gate placed twelve inches apart.
Some doubt having been expressed whether such a bar contained the requisite strength, a model bar
of the same form and length proposed was made of four plates of iron, twenty-two inches wide and
three-fourths of an inch thick, with lapping plates over the joints three feet long. This bar was first
tested by loading it, with the ends secured and resting against abutments.
A weight of 92,000 pounds was put on the middle of the bar, which deflected it two inches; the
yielding of the frame prevented any further weight being applied, but it was subsequently tried with-
out abutments, and deflected three inches with 50,000 pounds; six inches with 65,000 pounds; ten
inches with 71,000 pounds, and broke with 75,299 pounds; the fracture being a rent near the middle,
extending up from the lower edge six inches.
The floating gate is a vessel sixty-six feet long, sixteen feet beam, and thirty feet hold. The keel
and stems are made to fit grooves in the masonry, at the lower end of the dock; by admitting water
into the vessel it sinks into these grooves and forms a barrier against the sea. It is removed from its
place by pumping out water sufficient to float the vessel clear of the grooves. Means are provided for
passing water through this vessel also, into or from the chamber of the dock.
This gate or caisson is built as follows:
The frame is made of vertical ribs of iron bent to the form of the vessel and covered with boiler-
plates, and stiffened with cast-iron tubes. The keel and stems are made of plates of iron, two feet wide
and five-eighths of an inch thick, with side plates of similar-sized iron, secured together and to the
sheathing by angle-iron riveted to each.
There are three decks; the beams are made of angle-iron four by two inches, and half an inch thick,
split at the ends to form braces; they are covered with sheets of iron one-fourth of an inch thick.
The stiffening tubes are sixteen inches diameter and one inch thick, and secured to the sides of the
vessel. The centre tier are open at both ends, and provided with valves to pass water through and
into the vessel.
The ribs are made of iron six by one inch, set edgewise, and secured to the sheathing by angle pieces
four by four inches, riveted to each. The upper part of the ribe is formed by welding on bars of angle-
iron three by three inches.
The sheathing is formed of plates, laid horizontally, about ten feet long and two feet wide. The
bottom courses are five-eighths of an inch thick and gradually decrease in thickness, and at the top are
three-sixteenths of an inch thick and four feet wide. Below the water-line the joints are lapped, and
above they are butted.
The bulwarks are carried up in a similar manner to the sides, and are lined.
The kcel is stiffened by the insertion of cast-iron plates longitudinally and transversely, and the keel
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is braced from and suspended to the sides, by a trussing of hollow cast-iron pipes five inches diameter,
through which are passed rods of wrought-iron, two and a half inches diameter.
Two windlasses are provided for warping. Hand-pumps are provided for emptying the vessel.
The joints of the sheathing and stems are chipped and caulked 80 as to be water-tight, and the whole
surface is painted to prevent corrosion.
The gates and the caisson were designed by Mr. McAlpine, and constructed by Mr. H. R. Dunham,
at the Archimedes Works, New York.
The dock is filled by means of culvert passages through the lower ends of the walls, which discharge
into the galleries leading into the main chamber.
The Pumping Engines-The tides are but about five feet, which renders it necessary to provide the
means of pumping out the chamber of the dock. For this purpose there has been constructed a steam-
engine of great power, and pumps of great capacity. The duty required is the removal of 610,000 cubic
feet of water in from two to three hours, as follows:
110,000 cubic feet to be raised an average height of 21 feet.
125,000
"
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"
71
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115,000
"
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"
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121
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The following are the specifications and dimensions of the engine and pumps:
A condensing vertical beam-engine, with a cylinder of fifty inches diameter, and a stroke of piston of
twelve feet. The piston-rod of the cylinder is attached to one end of the beam, and from the opposite
end the connecting-rod is attached and extended to the crank. The beam is of cast-iron, thirty-two feet
long, with suitable bearings provided for attaching the draining and air pumps.
The crank-shaft is of wrought-iron, turned and polished the crank is of wrought-iron, finished up.
The fly-wheel is placed on the crank-shaft and is twenty-four feet diameter, with a cross-section of
eighty square inches. The condenser is fifty-two inches diameter and five feet high. The air-pump is
made of cast-iron and lined with a staving of composition metal; it is forty-four inches diameter and
forty-two inches length of stroke, and is fitted with a floating top. The air-pump, bucket, foot-valve,
seat, and rod are of composition metal. The cylinder has double balance-valves, made of compo-
sition, with valve-stem of cast-steel. The side-pipes are of cast-iron, turned and polished, and provided
with an expansion-piece. The cut-off motion is self-adjusting, 80 as to admit an increased quantity of
steam to the cylinder, as the duty on the engine increases by lifting the water to a greater height. All
of the connections of the engine are of wrought-iron, and those above the bed-plate are finished and
polished. The piston of the steam-cylinder has metallic packings moved by steel springs.
All of the boxes of the journals are of composition and lined with Babbet's metal. Automaton oil-
cups are fitted to the principal journals.
The engine is fitted up with a register, a steam and vacuum gage, and an indicator.
The engine-frame is of cast-iron, with a bed-plate set upon a granite foundation raised eighteen inches
above the floor of the engine-room. Upon the bed-plate are five gothic columns, and two pilasters on
each side. The columns sustain gothic arches of ten feet span and an entablature, all of cast-iron.
The engine-frame is surrounded with an iron railing. All of the work which is not finished or polished
is painted and bronzed. The space for three feet entirely around the engine is covered with a cast-iron
flooring figured in relief.
In the boiler-room are placed three marine boilers, made of the best Pennsylvania piled boiler-plate,
seventy-eight inches diameter and thirty feet long, with six hundred and fifty feet of fire surface
in each. The boilers are so arranged that one or all may be used, as occasion may require. Each has
a steam-drum, and cast-iron doors to the furnace and ash-pit. One of Worthington's feed-pumps is
attached to each boiler. The boilers are warranted safe to be used with a pressure of fifty pounds to
the square inch.
All of the steam, feed, connecting, and injecting pipes are of copper. All the cocks and valves are of
composition metal. All the joints are faced metal and metal.
Steam and water gages, and safety, feed, and blow valves are put on each boiler.
The steam-drums, pipes, and steam-cylinder are covered with hair felting; that on the cylinder is
cased with mahogany staving, reeded and banded with brass bands. The felting on the drums and
pipes is covered with hemp canvas, and painted.
All of the wrought-iron is hammered charcoal-iron, and the cast-iron cold-blast of the best, quality.
There are two draining-pumps, each of sixty-three inches diameter and eight feet length of stroke, 80
placed that one pump is driven by each arm of the beam. Each pump is provided with a suction-pipe
and valve-chamber, and valve, and floating-top. The two suction-pipes are connected, by a pipe, to an
air-vessel which is common to each.
The draining-pumps, air-pump, and condenser are placed on a bed-plate eleven feet below the bed-
plate of the engine. Between the bed-plates is a cast-iron reservoir, with hinge-valves to exclude the
tide-water, but which will open at every stroke of the pumps.
The chamber of the pumps is lined with a staving of composition; the bucket, rod, and valve, and
valve-seats are of composition; the valves are covered with vulcanized india-rubber. All the joints of
the pumps, pipes, and bonnets are faced metal and metal; all the connections which extend above the
bed-plate of the engine are finished and polished.
The engine and pumps were designed by Mr. McAlpine, and constructed by Messrs. Kemble, at the
West Point Foundry.
The Pump-well, Culverts, and Engine-house.-When the dock is to be emptied, the water passes
from the chamber, through the galleries, into vaulted passages in each wall, which unite at the head of
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DRY-DOCK.
the dock, and it is thence carried to the pump-well by a large culvert of cut-stone. The pump-well is
placed under the east end of the engine-house, and is built in an oval form, the two interior diameters
being thirty and twenty feet.
The foundation of this well and culvert being carried to the same depth as the foundation of the dock,
rendered its construction equally tedious, and the same difficulties were encountered, but its limited
area permitted the use of shores and braces, extending across the pit.
The disturbance which was caused to the ground in the vicinity, rendered it necessary to bring up a
stone foundation for the engine-house, from the same depth as the well, by a series of arches.
Leading from the pump-well is a culvert of cut-stone extending from the bay near the entrance of
the dock. for the purpose of carrying off the water which is discharged by the draining-pumps.
The engine-house is of fine-cut granite, three hundred feet long, sixty feet wide, and three stories
high. The part not occupied for the engines and pumps is to be used for a machine-shop for repairs.
The Machines and Tools used-A steam-engine, with a cylinder of fifteen inches diameter, and four
feet stroke, was erected to drive the temporary pumps used for draining the work during its progress.
These pumps were two forcing, of fifteen inches diameter and five feet stroke, capable of discharging
six hundred cubic feet per minute. Duplicate pumps and an engine were provided to prevent delay
and injury to the works by the temporary failure of the main engine.
After the dam had been repaired, the quantity of water which flowed into the pit did not consume
the whole of the power of the engine for its removal, and the surplus was applied in various ways to
facilitate the progress of the work.
Two other steam-engines, one of twelve and the other of five horse power, were used at times during
the construction of the work. These engines were all fitted up with winding-drums, by which power
was conveyed to the several machines.
The mud was hoisted out by tubs suspended from the booms of the derricks and by cars moving on
inclined planes. which were elevated by means of a rope leading to the winding-drums of the engines.
In a like manner the hammers of the piling-machines were elevated, and heavy stone were hoisted and
lowered on the cranes and derricks.
Grindstones, saws, planing and grooving and screw-cutting machines were also driven by the surplus
power of the engine. The edges of the flooring-plank, and the grooving and tonguing of the sheet-piles
were all done by machines driven by steam-power.
The drawings of some of the most useful of these machines will be found under the several heads of
stone-setting machines," lewis," "crane," "derrick," piling-machine," stone-jack," pumping-engine,"
" iron gates and caisson," where a full description of them will also be found.
It remains only to state how these machines were applied. The stone were chiefly transported on
cars; lines of railroad encircled the pit, from which branches led to within reach of each of the laying-
derricks, the piling-derricks, and the discharging-cranes. Of the latter there were seven, placed along the
wharves and coffer-dam, by means of which an equal number of vessels could be discharged daily.
This number was necessary, as in most cases the stone vessels arrived in fleets.
The stone were hoisted out of the vessels with the cranes, worked by steam-power, and loaded on
cars and transported to the stone-cutters' sheds or piling-derricks, where they were assorted and stowed
away. Thence they were taken as required to the laying-derricks placed around the margin of the pit.
The discharging-cranes were cheap machines. The piling-derricks were chiefly the old excavation-derricks
refitted. The limited area of ground assigned by the officers of the yard to the use of the dock ren-
dered it necessary to pile up the stone.
Under the head of lewis" are described a variety of tools used on this work for securing stone for
hoisting. Among them is a side-lewis, the invention of Mr. Lidgerwood, the master of masonry, which
deserves particular notice, as being the first instrument of the kind which has been got up to suspend
cut-stone without marring the upper surface; such as coping, altars, and steps.
The Cost of the Work.-The amount which has been expended to the 1st of October, 1849, is
$1,418,198.78. This sum has been classified under the following heads of expenditures, viz:
Offices
$69,418 17
Culverts and well
32,485 74
Coffer-dam
206,378 36
Temporary drainage and steam-
Earthwork
149,802 58
engine
105,139 07
Foundation
127,250 03
Workshops
104,293 23
Masonry
600,569 84
Miscellaneous
6,566 41
Gates
16,295 35
$1,418,198 78
It is estimated that the sum of $420,000 will be required to finish the work; but in these amounts
are included the value of machines and tools, the cost of constructing a machine-shop, and grading and
levelling the Navy Yard, which are inappropriately charged to the dock, and which, if deducted, would
make the cost $1,750,000. This great cost has arisen from the frequent changes which have been made
in the officers of the work, and by the failure of the original coffer-dam, and by the unfavorable nature
of the soil, and the difficulties experienced in getting down the foundations, and by the great en-
largement of the structure beyond the size originally contemplated.
Description of the Drawings.-Fig. 1137 shows a plan of the masonry. The entrance to the dock is
at SZ; near by is shown the groove into which the caisson or floating-gate is sunk. DDDD represent
the four capstans which open and close the two folding-gates. GB is a drain sunk below the level of
the floor of the chamber.
Fig. 1138 represents an elevation of the walls, and also of the timber and pile foundation. The
entrance to the dock is at f, the groove for the floating-gate. At A is the recess to receive the
wing of the folding-gate when open. B to y represents the chamber in which the vessel is received. At
K is the gallery leading to the exhaust culverts running through the walls, a section of which is shown
at J. PPPP represent the piles which support the structure, on the top of which are shown the
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DYNAMOMETRIC CRANE.
405
timbers and plank. In Fig. 1139 is shown a section of the walls through the point marked A on
the plan and elevation, being the recess to receive the folding-gates when they are open. The culvert
passages which are used to fill the dock are shown at F.
Fig. 1140 is an elevation of the entrance wall, showing the filling culverts at F, and the slides at the
head of the dock for lowering timber by I.
Fig. 1136 represents a section of the dock in the receiving-chamber, with a line-of-battle-ship resting on
the keel-blocks and shores. The exhaust culverts are shown at E. In all of these drawings the most im-
portant dimensions are marked in feet and inches, which obviates the necessity of any further description.
DYNAMOMETRIC CRANE: of Messrs. Lasseron and Le Grand. This machine, for which inven-
tors have taken out a patent for 15 years, dated 13th April, 1843, and for improvement dated 31st
October, 1843, combines the two great qualities-
First, That of indicating the weight of objects raised.
Second, That of retaining its equilibrium of itself, whether placed upon a moveable wagon or railroad.
Its first condition is obtained by means of a horizontal lever having at one end, together with a pulley,
the chain by which the weight is suspended. The other end communicates with a scale to which are
fixed proportional weights. The action is merely that of a steelyard operating in the interior of the crane
at the same time as the crane itself, and is sure of indicating an exact weight whatever may be its extent.
To obtain an equilibrium the crane has two beams, forming in its upper part a horizontal line, upon
which runs an iron-way of which the incline is determined. A counterbalance, sliding upon this iron-
way, represents half the maximum of the weight that the crane is destined to raise. When the crane is
inactive the counterbalance is at the end of the beam which raises the weight: in this state it finds its
own equilibrium; since the opposite beam is charged with a weight exactly equal to its counterbalance.
The equilibrium of the crane will not cease if in the action of raising a given weight-the counter-
weight falls in proportion-thus giving a like amount of weight upon each beam.
The chain for raising the weight passes and presses at the same time upon a lever marked at one of
its extremities. The other extremity, drawn by the movement of the pulley, has a rope or chain which
winds upon a conical cylinder. Upon the axis of the cylinder is fixed a pulley which communicates
with the counterweight in such manner that this pulley revolving as the marked lever, describes a
greater arc; that is to say, as the weight raised is heavier, so will the counterweight retire in such pro-
portion that the equilibrium will not be lost. In the same ratio as the chain distends and the weight
raised is discharged, the counterweight resumes of its own accord its normal position.
By the system of balancing, making all weight rest upon the pivot, the adjustment of the crane is
rendered easy, and the weight suspended to the beam can be placed upon any point between the two
tangent lines, within the circles of rotation of the crane, and parallel with the iron-way. A machine
constructed upon such principles would be of infinite use in the working of railroads, as it can be re-
moved to wherever its service may be required, which is often more economical than to bring the goods
or merchandise before a stationary crane. It might with equal advantage be worked in factories, &c.,
or for the removal of large pieces of foundry-work.
Description in detail of the Crane.-Fig. 1141 is a representation of its longitudinal elevation section-
ally. or supposing one side to be removed in order that its mechanism may be more fully developed.
Fig. 1142 is a side elevation.
Fig. 1143 is a horizontal projection or a section of its upper works complete.
Fig. 1144 is equally a horizontal one, but taken from one side at the line indicated in Figs. 1144,
by 1-2.
The other figures represent more in detail the principal pieces of which this crane is composed.
Body of the Crane.-In order that this machine should maintain a constant equilibrium, it is con-
structed with a double arm, which makes it exactly symmetrical on both sides of its axis. The arms
are each composed of two side-pieces A in cast-iron, parallel and in form of a triangle, of which one side
is vertical, the second horizontal, and the third is a curve. These side pieces are applied on the inside
of the mountings B in cast-iron, to which they are bolted at equal distances, Fig. 1144.
These mountings form a kind of pilaster, and are strengthened by a strong cast-iron square C, and
by many trusses or bolts which maintain them in their position. Upon the horizontal sides of these
side pieces are inserted plates of iron b, which serve as adjusting-screws. They are surmounted with a
rectangular balustrade D in cast-iron, which serves for ornament, and at the same time conceals and
restrains the moving counterweight, which should always balance the weight raised In the centre of
the square plate C, a cavity or kind of cup is hollowed out hemispherically to receive the steel-pivot c,
fixed upon the summit of the conical column E, upon which rests all the machine. This column is cast
with a square platform F, which serves as base to the machine, and upon which the men can stand as
occasions may demand.
To make the crane capable of being removed, four supports G are inserted in cast-iron, which are
screwed on underneath, and in which are adjusted brackets dd, Fig. 1145, for the purpose of receiving
two wrought-iron axes of the wheels H in cast-iron. To make the transport more easy, the wheels are
made to rest upon two iron bands I, arranged in the direction required for use, and upon which they
can roll in the same manner as upon a railway.
In order to have all four wheels bearing on the rails with equal weight, through the upper bed-plate
d are adjusting-screws e, which being screwed into the thickness of the platform, permit the apparatus
to be placed perfectly horizontal. It is also necessary to have the whole mounting perfectly in equili-
brium upon the pivot c. round which it should freely turn, 80 that the equilibrium should not be broken.
The lower sockets d only serve to maintain the axes of the wheels in their position, and can easily be
held in their place by a simple bolt or linchpin.
The handle by which the winch is turned is not directly placed upon its axis, but upon a lower shaft,
with a pinion g in cast-iron, of 5 inch pitch diameter, and which works within an intermediate wheel K.
The diameter of this is 8 feet 6} inches; its axis h works upon pillows. The sides of the check-pieces
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have another pinion of the same diameter as the first, but more strongly dented, and which works within
the large wheel L, mounted upon the axis of the winch. M is a cast-iron cylinder, upon the surface of
which are grooves wormed spirally, so as to receive the thickness of the rings of the chain o which bears
the load. A second similar cylinder N, but smaller than the preceding one, is brought against this upon
the same axis to receive a smaller chain i, which is intended to balance the weight of the former. At the
end of the large chain is a swivel-hook j, to which the weight about to be raised is attached. All this
mechanism is concealed by the two side-pieces of the crane, with the exception of the handle of the
windlass.
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Equilibrium of the Crane-This machine is the more interesting, by reason that its inventors have
made it capable of always finding its own equilibrium without care or inspection, without reference to
the weight it may be about to raise. To arrive at this, at the extremity of one of the arms of the crane
a weight Q of cast-iron is fixed to the two cheeks by bolts or screws. This weight alone would evi-
dently cause the machine to fall over, but it is counterbalanced by another, R, capable of advancing or
retiring, like a wagon, over the entire length of the beam. So long as the crane is inactive, without a
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DYNAMOMETRIC CRANE.
407
weight to raise, the counterweight R remains naturally at the extremity of the right-hand shaft and coun-
terbalances Q. But from the moment they commence to raise a given weight, the counterweight must
displace itself and advance from right to left, to enable the machine to retain its balance. It has for
this purpose four cast-iron wheels C, which allow it a free action, passing upon two iron rails S, and to
which is given from the first a slight incline that can be regulated at pleasure by the adjusting-screws K.
The motion of the counterbalance weight is effected, not by the workman, but by the load this crane is
raising. The counterweight, or moveable wagon R, is attached to an endless chain, which, passing over
the guide-wheel T, of which the axis is at the extremity of the two inclined rails, is attached to a point
of the circumference of the large grooved pulley U. This is cast with two smaller pulleys, Fig. 1147,
on one of which a second chain m is attached, which is fixed at the end of a wrought-iron lever V.
It is evident that if this end of the lever descend, the pulleys turn as indicated by the arrows, and the
chain m is wound upon the greater pulley, and of necessity the counterweight is drawn from right to
left. It is already perceived that to effect a displacement of the counterweight, it is only necessary to
attach the load to the lever V. Having given the levers the form of a fork twice bent, as indicated in
Fig. 1142, it is suspended to the arms of the crane by means of an iron axis n, which traverses them
at their extremity; then at some distance from this axis is placed between the same branches a pulley V,
over which passes the chain which bears the load, Fig. 1141. It is evident from this, that the more the
weight, the more the pulley is pressed; consequently the more the forked lever tends to descend, the more
of necessity the counterweight R advances to the left of the machine. This arrangement, so simple
in itself, could, without difficulty, be applied to any kind of crane, moveable and with double beams, by
the addition of a counterweight in the upper part. And it is entirely independent of the dynamometric
system, neither would it embarrass the same in any manner. It is hardly necessary to remark, that from
the moment the crane is relieved of its load the lever is free; the counterweight passes upon its inclined
plane to recover itself at the extreme left of the machine; and that it may do 80 conveniently, the
extremity of the two rails S are slightly bent.
Dynamometric Mechanism.-The mechanism added by Messrs. Lasseron and Le Grand, to indicate the
weight of the burden raised, is very simple in its arrangement, and the more curious that it does not
interfere with the original construction of the machine. It is merely an addition that can be applied to
any description of crane.
This mechanism consists in a large wrought-iron beam X traversing as a steelyard by a steel axis o,
carefully cut in the form of a knife, that it may act only upon any sudden jerk of the two steel cushions,
which are adjusted upon two iron cross-pieces p, bolted in the interior of the side-pieces of the crane.
This disposition will be more intelligible on reference to Fig. 1148, which represents a vertical section,
following the indicated line 5-6 of Fig. 1141, and by Fig. 1149, which gives in elevation and plan the
details of a cushion or pillow and cross-piece. The beam is divided by the axis o in two different parts
to form two arms of unequal length, of which the shorter should carry the load, and of which the longer
should communicate with the balance-scale. At the extremity of the shortest arm of this lever are
suspended two iron checks q bound between them by a clamp, Fig. 1150, and reunited at their lower
end by a horizontal axis v. They are furnished at their summit with two guard-plates, which hide the
knives, by which they come in contact with the beam. The axis r has at its middle the grooved pul-
ley Y, Fig. 1151, on which passes the principal chain O. The lateral movement of Y is prevented by the
small checks S, (in detail Fig. 1152,) one end attached to the lower end of the checks Q, the other to the
frame at t.
The axis r is extended beyond the two external ends of its knives, to form pivots, which, when the
machine only acts as an ordinary crane, carry the two supports v, bolted on the inside of the side-
pieces, so as not to wear needlessly the knives; but these pivots are quite free when the crane acts
as an indicator of weights. From knife edges at the extremity of the longest arm of the lever, a rod u,
Fig. 1153, is suspended, whose length can be adjusted, and of which the lower end, also forked, affords a
support for the knife edges 2, Figs. 1154 and 1155, of the lower lever x. At the extremity of the longest
arm of the steelyard, is suspended a long bar u; to this effect it forms a fork at its upper part, as well
as its lower, but this is brought opposite, Fig. 1153, to allow you to regulate the exact length of the
bar, according to the distance which should exist between the beam and the lower lever a, which it
serves to unite. This union takes place at both extremities by the introduction of steel knives 2, which
destroy the friction, Fig. 1154, and yet permit all the freedom of action desirable. The lever = is at
one end in the form of a horse-shoe, (see the details, Figs. 1154 and 1155,) 80 as to give it more
firmness upon the axis Y. The other end of the lever is in form of a hook to receive the scale Z,
placed as those of an ordinary balance to receive the weights. It can be understood, that in the con-
struction of a like machine, the lengths of the lever, and of the great beam, can be combined, as is
done upon the steelyards, or in the ordinary scales.
Thus for machines of a small kind, in most cases, it would suffice to allow 1 to 10 lbs, that is to say,
that a given weight of 1 lb. should balance 10 lbs, suspended at the extremity of the chain O. With
cranes of an intermediate or larger size, they might allow 1 upon 20, or 1 upon 30. That is nearly
about the allowance for the machine here represented.
It will be perceived that the knife x, Fig. 1154, is at some distance from the point of rest y, equal to
0.270, and the total length of the lever is 0.880; consequently the proportion is
0-27 : 0.88 :: 1 3-25.
The smallest arm of the steelyard X has for length 0·440, and the longest 3.82, which gives
0.44 3.82 1 : 8.68.
Consequently the product of the two gives
1 : 3.25. X 8.68 = 282.
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DYNAMOMETER.
If the differences of the two pieces be added to enable them to be in equilibrium, it will be seen, that
the ratio between the power and the weight placed upon the platform Z is to the resistance or weight
added to the end of the chain as 1 30. With the lower lever x is forged a vertical branch a', Fig. 1154,
joined at right angles, and terminated in form of a knife acting as indicator, and corresponding with the
point of a similar piece b', fixed against the cast-iron cross-piece C.
When the load is in equilibrium with the weight on the platform, the sharp edges of these knives
ought exactly to coincide, as they do at a' b', Fig. 1141. Therefore, weights must be put into, or taken
from the scale, until this end is obtained.
Equilibrium of the Weight of the Chain-With such disposal of the mechanism as adopted by the
inventors, it was indispensable for the exactitude of the machine to make an allowance for the differ-
ence of the weight of the chain O. To overcome such, Messrs. Lasseron & Le Grand have cast a
second roller N, of much smaller diameter, alongside that which bears the chain, and upon which the
small chain i can wind itself, which, passing as the chain o upon the throat or neck of the pulley V',
passes on still to a guide pulley c', placed in the upper part of the crane, and from there to another
pulley d', carried by the extremity of the steelyard near the point of suspension of the long rod u.
A small counterweight e' is attached to the extremity of the small chain to balance the exposed portion
of the chain O. Or when this winds itself upon the winch, and passes upon the pulleys Y and V',
and besides upon the guide pulley A', which causes it to take the proper direction, the small chain
winds itself equally and in proportion upon its own small windlass N, and so diminishes as much the
load at the end of the steelyard. In like manner, as the thickness of this smal lchain has been calcu-
lated beforehand, 80 that a given length acting upon the steelyard balances, with an equal length
given of the chain o, by reason of the difference of circumference of the two winches, and of the arms
of the steelyard, a conclusion as nearly correct as possible is immediately arrived at.
Equilibrium of the Weight of the Steelyards.-The inventors have also endeavored to balance the
weight of the steelyards; fearing that in the cranes of large dimensions this difference of weight
might be considerable. In a certain point of the larger beam X, they adapt by means of a knife a
double forked piece of iron, detailed, Fig. 1157, which in its lower part rests upon the extremity of a
counteracting lever g', which also moves upon two knives, that carry the steel bolsters dovetailed on
the iron way h'.
This one represented in elevation, Fig. 1158, is fixed between the two side-pieces of the right arm of
the crane, and has two square blades which serve to preserve the bolsters and knives. At the ex-
tremity of the lever f' is a counterweight, either in lead or cast-iron, to overcome the weight of the great
arm of the lever of the steelyard.
DYNAMOMETER, invented by S. Brown, of Lowell : the principle of which consists in measuring
the power used by weighing the strain on an intermediate geer.
1159.
y
B
A
c
E
Description-A is a pulley, Fig. 1159, which receives the power from the driving-pulley, which is trans-
mitted through the geers CD and E to the pulley B, thence to the driving-machine. The pulleys are out-
side of the frame, the geers CE inside of the frame, and supported by it; the intermediate geer D hangs
in a stirrup, supported by the beam F, which is a steelyard, whose fulcrum is f. But it must be remarked,
that the strain on the centre of the intermediate geer (since the pilot line of the geer on one side is the
point of application of the power and on the opposite side is the fulcrum) is double the power transmit-
ted by the machine. G is a cylinder filled with water, in which a piston, fitting loosely, is attached to
the beam F, and is used as a regulator to prevent sudden oscillations in the beam, which invariably oc-
cur in such machines.
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DYNAMOMETER.
409
DYNAMOMETER. Figs. 1160 and 1161 are two views of a dynamometer constructed on the prin-
ciple of what is called the differential-box," and consists of two pair of belt-pulleys A A, BB, mounted
on the shaft CC: one of these pulleys on each side is loose, while the other is fast. The fast pulley
on the side A A, and the bevel-wheel D, are both fastened to the shaft C C. The bevel-wheel F is
fastened on a small tube connected with the pulley B. The wheels EE are connected by G, which is
constructed 80 as to revolve round the shaft C C. To apply this simple machine, a belt from a druni
on the main driving-shaft is brought to the pulleys AA, whilst another belt is carried from the pulleys
BB, to the machine or machinery, the weight of which is to be ascertained. And it is plain, that if the
pulleys A A, and the wheel D, are once put in motion, the wheels EE will also revolve on their axis,
and at the same time the connection-shaft G will revolve round the shaft CC, thus leaving the wheel F
and the pulleys BB, standing still; but, if the wheels EE are kept in their present horizontal position,
and prevented from revolving round the shaft C C, it is equally obvious, that the wheel F and the
pulleys BB will then be moved at the same speed as the wheel D and the pulleys A A; hence the
weight required to keep the wheels EE in their present position, is equal to the weight required to
move the pulleys BB. The weight thus required, is found by means of the lever HJ. The arm H is
attached to the centre of the wheels EE, by the straps aa, Fig. 1160. The arm J is divided upon the
principle of the Roman steelyard. The weight M is merely intended to balance the arm J, and being
1160.
1161.
J
J
16
1%
n
8
8
4
1
N
1
a
E
E
G
H
C
D
F
E
E
a
A
B
P
M
M
H
fastened with a set-screw, can easily be shifted on the arm H, as may be found requisite. Therefore,
when the wheels EE are kept in their present position by means of the lever J H, it is evident that a
weight of 20 lbs. acting upon the pulleys A A at P, will balance another of the same weight at N, of
the pulleys BB. Now the distance from the centre of the shaft CC to the division on the lever J
marked 1, is equal to the radius of the belt-pulleys; hence a weight of 20 lbs. at 1 will counterbalance
the same weight at P,-that is, making no allowance for friction, the amount of which is ascertained by
the additional weight required to balance the given weight at P; and having once ascertained the proper
allowance for friction, the machine is put in motion by shifting both belts on to the fast pulleys, and
moving the balance weight along the lever J from 1 to 4, 8, 12. or to whatever number will balance
the wheels E: and the weight thus indicated on J, is the weight required to move the machine or
machines, from which deduct the allowance for friction. A worm at y on the end of the shaft C C,
works into a wheel with an index and pointer, in order to show the speed at which the machine is
driven, and also to determine the difference of the weight of any machine at different speeds. From
the above description it is presumed that the principle upon which this dynamometer is constructed,
as well as the mode of applying it, will be easily understood.
An improvement has been made on this machine by J. B. Francis, Esq,, of Lowell, by which the
52
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410
DYNAMOMETER.
power is transmitted to and from the dynamometer in the same line; thus, instead of the pulleys B B,
a geer is employed, which works in an equal geer fixed to the end of an extra shaft parallel to CC, on
the opposite end of which, and on a line with A A, is a pulley of the same size as A A, from which
power is transmitted to the machine to be driven. The beam is balanced without the use of a moveable
weight M, and to this end a regulating pump is attached, as in Brown's machine. A clock is driven
by an endless-screw on the extra shaft, which registers the revolutions of the shaft, and a bell strikes
at every 50th revolution. The beam J is 80 graduated, that the power used, or weight raised 1 foot
high per second, is obtained directly, by dividing the weight as shown on the beam, by the number of
seconds occupied by the shaft in making 50 revolutions. The friction of the machine was taken by the
use of Prony's friction break, placed on the extra pulley, and was ascertained exactly by a course of
experiments, on different speeds and weights.
DYNAMOMETER. Regnier's Dynamometer resembles a common graphometer, the principal part
of which instrument is a steel spring bent in the form of an ellipsis; it should be properly tempered,
and well welded, and covered with leather, to prevent injury to the hands when used. This spring is
represented by A A', B', formed by two equal plates united at the ends by rounded half-rings.
The dimensions of this spring vary according to the tension required, or the weight to which it is
applied.
The dynamometer used to ascertain human strength weighs little more than two pounds, and serves to
measure a thousand times that weight; its total length is about 12 or 13 inches, and its greatest breadth,
as measured in the middle of the two arcs, is 2.2 inches, and the least breadth at the extremity of
these arcs is t of an inch. The thickness of the arcs at their centres is nearly 2 inches, and its height,
which decreases from the centre towards its ends, from I's to I'o of an inch; the chords of the two ares
are 6·4 inches. This length, added to that of the two demi-rings, gives for the total length of the
dynamometer 12 or 13 inches. The distance between the parallel chords is about t of an inch, and the
perpendicular of the arcs are each 10 of an inch, giving about 2-2 inches for the total distance between
the centres of the arcs.
1162.
L
I
A'
E
B
D
T
B
o
&
BU
N/
L
d
M
ODPY
H
N
B
There are two methods of stretching the spring, by pressing it in the direction of the perpendicular
of the two arcs which form it, or by drawing it with the two rings at right angles to that perpendicular
these two limits of tension are indicated by two scales drawn on the same limb, called scales of pressure
and tension : the first gives the pressure of weight from zero to 264 pounds avoirdupois. The greatest
pressure brings the centres within 04 of an inch of each other, each perpendicular, which is 07 of an inch
when there is no pressure, is reduced to 0.5 of an inch. The brass limb on which the scales are drawn
is fixed on the centre of the arc A' B' of the spring, and the opposite arc A B carries a counterpoise
a b, 3.1 inches long the extremity b of this counterpoise acts on a small branch b H, 0.3 of an inch of a
bent-lever, b Hc, whose other branch H c is a needle, 2.4 inches long, from the centre H of rotation to
the index c. Below this index is a small cylindrical thread, 01 of an inch, which is fixed to the needle
Hc, and serves as a foot when it turns on the centre H, parallel to the limb. This first needle by
turning communicates a rotatory movement round the centre K to another needle K dd which rolls on
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DYNAMOMETER.
411
the smooth portion of the screw K, and leans on the limb by a foot G furnished with a washer to re-
duce friction. This second needle has two indices d and d, to mark the pressure and traction; it is
moved by the first needle H c; the divisions of the arcs described by the two indices are numbered in
pounds, which indicate the weight brought by the needle to these divisions: as long as the spring is not
stretched, the needle H c preserves its primitive position, and the needle dd' of the scales remains on
the divisions to which it is drawn by the tension of the spring; whence it is seen that the system of
two needles gives us the power of preserving the measure of a tension, when the force which produced
this tension no longer acts. The greatest arc which the needle H c can describe is determined by the
course of the counterpoise a b, which is 039 of an inch. The points b and c of the bent-lever GHc
describe arcs of the same number of degrees: with regard to the positions of the two needles Hc,
Kd d' to the right line HK L of their centres, the angle which the second needle makes with
this right line, is equal to the angle c HL of the first with the same right line, increased by the vertical
angle H c K of the two needles, for in the triangle H c K, whose sides H c and HK are constant, the
angle c K H is the supplement of the angle c KL, and of the sum of the two angles c and H c K.
The distance HK of the centres H and K is about 0·46 of an inch, and it results that the total arc de-
scribed by the needle <dd is nearly one-third of the circumference.
To preserve from injury the system of these three pieces, viz., the counterpiece a b, the bent-lever
bHc, and the needle with two indices dd', the limb is covered by a plate NNN, which rests on the
three pillars, 0.39 of an inch high. If the axis of rotation of the bent-lever were prolonged, it would
meet this plate in the point H', the centre of the arc of a circle m' m" which terminates it, and whose
radius is equal to the length of the needle Hc. The divisions of the arc m' m" are figured, and the
figures indicate the same tensions as those on the scale of traction.
The dynamometer just described indicates on the scale of traction a tension of a ton weight, which is
greater than the most powerful effort of a horse, but nevertheless too small to measure the ordinary
effort of a power applied to a screw.
M. Regnier constructed a dynamometer on the same principles, which measures a traction of 6,600 lbs.
the spring was of the same power and length as the old one, but the two arcs or plates of which it
was composed were longer, thicker, and further apart in their centres; their distance from each
other was 45 inches; by the greatest traction it was only diminished 04 of an inch; these arcs had
in the middle a breadth of 1.8 inches, and a thickness of 02 of an inch; the total weight of the instru-
ment was 53 lbs.
By placing the machine between the two ends of a cord passing over two or more pulleys, the ratio
of the force which separates the extreme pulleys to the tension of the cord will be known, and by this
disposition we can measure a traction much more considerable than that which is indicated by the scale
of the dynamometer. Fig. 1162 shows the arrangement with two pulleys.
Details of the Construction of the Dynamometer.-Two supports DD' of steel, are adjusted solidly
on the two opposite branches of the spring in the direction of the perpendicular of the axis. The first
support D, cut in a fork, carries a screw on which the extremity a of the counterpoise a b rolls; it is
about 14 inches high, and 0.59 wide; it is retained on the centre of the arc A B by a strong screw, whose
head is marked T on the convex part of the arc. The second support D is also retained by a screw, the
extremity of which, t, is seen on the concave part of the arc A' B'; the upper face E E of this support
is about 4 inches long: on the opposite face EF, which is of the same length, is a brass plate I L, fixed
by a single screw g, which is level with EF in the plate, hardened to make a spring, carries at its
extremity a pivot I, which passes through the support and the limb; this pivot, like that of a compass-
needle, serves as a centre to the bent-lever b H the limb is applied to the face EF of the support
D', and is fixed there by two screws e f. The plate IL being a spring, the pivot I yields to a
pressure of the counterpoise, and prevents any rupture of the mechanism which turns the needles of
the scales.
The covering plate OPQ is voided at K' in a small circle of a diameter nearly equal to that of the
head of the screw K, round which the needle K d d works, with a slight friction on the limb: if this
friction be too slight, a turn-screw which passes through the circular opening K' will tighten the pressure.
The lower pivot of the bent-lever b H c rolls on the pin I'; its upper pivot rolls on the side H', which
is riveted to the covering plate OPQ
Spring-Balance and Eprouvette. The spring-balance most used in commerce is formed of two steel
branches A C, CB, bent at an angle of 45°; each of the arcs D pq E, I H G, is fixed to one of the
branches and traverses the other. By drawing the rings EG, which
terminate the ares in opposite directions, we bring the branch AC
1163.
near BC; a circular scale figured from 5 to 40 indicates the respec-
tive positions of these two branches. The branch AC pushes before
it a small cursor k of card or leather, which slides easily on the
C
metalic wire fg, attached to the branch CB of the balance. To
graduate the scale, suspend the balance by a ring E fixed to the
branch A C, and attach weights to the ring G, which is at the ex-
tremity of the scale. The numbers on the scale indicate the tension
of the spring.
Regnier has made an excellent instrument of this spring-balance
for trying the strength of powder. The length of the branches A C
a
and CB is about 48 inches, and their breadth about an inch; a small
L
brass cannon, whose breech H is on the branch CB of the balance,
and whose mouth I is closed by the fuse I L of the obturation DILE
1
fixed on the other branch A C of the balance, contains a given weight
of the powder to be tried; it is primed by a little powder put in the
pan F: the powder within the cannon is fired and drives it away; after the ignition the two branches
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412
DYNAMOMETER.
of the balance approach, and the cursor k indicates on the scale the tension of the spring at the moment
of the explosion. The iron DE, and the brass arc G H on which the scale is drawn, pass through
openings pq, r 8 made in the middle of the plates CB and CA.
A dynamometer for measuring animal force was invented by Mr. Graham, and afterwards improved
by Desaguliers, but it was found to be inconvenient for the purpose, as it was made of wood. Leroy
afterwards formed one in a metal tube 10 or 12 inches in length, with a spring within it placed vertically
on a stand. This, however, was not found so useful as Regnier's, where the sides of the spring are made
to approach each other, and move an index, which marks the degree of approximation on a semicircu-
lar scale: a man can ascertain by it the mean force he exerts with either hand, or with both together
it was with this kind of dynamometer that M. Quetelet, of Brussels, made his experiments upon the
strength of men of different statures and ages.
Another kind of Spring-Balance.-The spring of this balance is bent in a curve CKD, terminated
by two braces, C B, DE, one of which supports the pinion I, and the other a rack D EGH, of which
the toothed portion GH catches the pinion L This pinion and the needle which marks the tension of
the spring turn on the same axis.
The face is a circle whose centre is on
the axis of the pinion I, and is fixed by two
1164.
screws t and t', on the plane T V, which is
soldered to the upper brace AB, which
carries the pinion. To graduate the scale,
suspend the balance by the ring A, and
attach known weights to F by the hook d c.
The rack G H will work the pinion I, and
the needle fixed on the axis of this pinion
&
V
takes up successively the positions figured
V
from 0 to 100; these numbers express the
t'
d
20
force of tension on the spring in pounds.
The index of the needle describes about 1
of the inch as the maximum tension of the
spring, or for the greatest distance between
the extremities C and D of the spring,
a
which is about 11 inch.
M
L
K
The plane of the balance being supposed
5
vertical, as in the projection, on another
H'
vertical plane passing through the axis of
the pinion; the face of the brace A B, per-
3
pendicular to the plane of the limb, is
B
drawn parallel to itself in A'B'; we see
D
on this face in the parallelogram 1 2 3 4,
the projection of an opening made in the
thickness of the brace AB, to make way
for the toothed part GH of the rack; the
breadth, 12 or 34, of this opening is 4
inches; LM is the projection of the axis
E
of the pinion I; the spring CKD is pro-
jected in CD; the plane on which the face
is screwed has for its projection TV. The
spring is 0·11 of an inch thick, and 12 inches
broad. To render this balance more con-
venient, a needle is added, which turns
freely on the face round the axis of the pinion I, and may be employed as the dynamometer; it is even
preferable for measuring the ordinary strength of men.
Of the Dynamometric Machine, and the Measurement of the Tangential Force of an Axletree.-Let
A B, Fig. 1165, be the section of an axle moved by water or any other power; an unknown but con-
stant resistance acts tangentially to this axle, and we require to measure it. To resolve this question,
suppose we fix on the axle A B of a wheel DEFGH, of any number of rays CD, CE, CF, &c.; this wheel
turns with the axle. Another wheel having the same number of spokes, C d, Cc, Cf, turns freely on
the same axle; springs Dd, Ee are attached to the couples of the spokes, D, Cd, CE, Ce of the
two wheels, 80 that the points of attachment D and d of the extremities of the springs are in a plane
perpendicular to the axis of rotation C of the axle A B, and at an equal distance from this axle.
Having disposed the power or mover so that it shall turn the wheel freely in the direction of the
arrow X, it is evident that the extremities de,fg of the springs fixed to this wheel, would swerve from
the points of attachment DEF, &c.; that the equal angles D d, Fce, Ecf, &c., whose sides pass
through the extremity of the springs, considered in their primitive position, would become other equal
angles Ded, Ece, Ecf, &c., and all the other springs would be stretched, if not equally, at least at
the same angle: when the total tension of the springs is equivalent to the resistance applied tangentially
to the axle, the system of the two wheels will turn on the axis A B as one and the same wheel. Now
suppose that the axis turns, and that we can measure one of the angles D d', at which all the springs
are stretched, we shall have in the triangle DCd the angle C, the equal sides CD, Cd, and conse-
quently the perpendicular let fall from the centre C on the side Dd, or the radius of the circle to
which the force which stretches the spring is tangential. We may, besides, observe the number of
turns of an axis in a given time, whence we may deduce the velocity of the point at which the force
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EARTHWORK.
413
that stretches each spring is applied. Multiply this velocity by the sum of the tension of the springs,
the product will be the dynamic effect of an axis in a unity of time, for example 1".
To measure the angle D c d, which moves in a plane perpendicular to the axis of rotation C of the
axis AB, we fix on the lines Cd, CD, the middle of the radii, two small hammers a b, coupled by a
spring Dd, which each moves in a plane perpendicular to the axis of rotation C, and at equal or unequal
distances from this axis, but greater than the radii of the wheels. These hammers strike two bells
placed beyond on circles described through a and b. This being arranged, we can with a seconds watch
measure the time which elapses between the two consecutive sounds resulting from the blow of each
of the hammers on the bells, and knowing besides the time of the entire revolution of the hammers,
these two portions of time will be in the ratio of the arc which measures the angle of the right lines
passing through the extremity of each spring to the entire circumference. This angle being known, we
can easily measure the weight which stretches each spring at a known angle, and the sum of these
weights will be the total tension of the dynamometric machine.
1165.
By this description it will be seen that simple springs without needles or scales, whose force of tension
for the same lengthening may be sensibly unequal, give exactly the measurement of a tangential force
applied to axes: by taking springs capable only of a tension of a ton, we may place eight on a circle
of 3937 inches radius, and eight others on a concentric circle of 8 decimetres, supposing the axle makes
four turns per minute; the dynamometric machine will show, on this hypothesis, that the dynamic effect
produced by a force applied to an axle is nearly equivalent to that obtained from 80 horses.
Another dynamometer deserves to be mentioned: a vessel containing water should have a cylinder,
made of some heavier substance than the water, suspended in it by a rope passing over a pulley: when
the upper surface of the cylinder is on a level with the surface of the water, the weight of the cylinder,
or the force which it exerts upon the rope, will be equal to the absolute weight of the cylinder in air
diminished by the weight of a quantity of water of the same magnitude as the cylinder: a horse or a
man pulling at the rope to raise the cylinder above the fluid surface, the weight of the cylinder will
gradually increase; and if the magnitude and specific gravity of the cylinder are duly adjusted to the
force, there will be a particular position of the cylinder at which its weight will exactly balance that
applied. The forces in equilibrio, or those required to be measured, will be equal to the absolute weight
of the cylinder, diminished by the weight of a quantity of water equal to the magnitude of the immersed
part of the cylinder: a scale attached may be so set out, that it will accurately measure the force ap-
plied, and the cylinder can be increased to any length by diminishing its diameter, so that a very
lengthened division may be adopted.
EARTHWORK, wagons for executing. Figs. 1166 to 1169, a wagon generally employed on railways;
this wagon is tipped at the end.
Figs. 1170 to 1173, a form of wagon much in use; this wagon is tipped at the side.
Figs. 1174 to 1177, wagon tipped at the end.
Figs. 1178 to 1181, wagon tipped at the side.
The flanch of the wheels is about 1 inch deep, slightly bevelled off from the inner side to the outer, so
that when the wheel is running in a straight direction, the edge of the flanch is kept about an inch clear
of the rail, or from coming in direct contact with it: this is effected by making the tire, which is 4 inches
broad, slightly conical, the inclination being about one part in seven or eight. Where the flanches are
not bevelled or are too shallow, the carriages are very apt to run off the rails, and should they come in
contact with a defective joint in a rail the same evil islikely to occur.
Wagons 6 feet in length and 2 feet deep, are found convenient on railways for carrying earth and
ballast, as well as the other materials required whilst the works are in progress. The plans, Figa.
1169, 1173, 1177, 1181, show the under side of the framing, consisting of two stout longitudinal
timbers to receive the iron axles, upon which the wheels turn. The bottom of the wagon is further
strengthened by iron plates, and a three-quarter round iron bar passes from one side of the frame to the
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ELECTRICITY.
other, to hold them together in the middle, and to aesist in supporting the load at the bottom. The
uprights at the sides are mortised into the bearer at bottom as well as the top rail, and at each angle is
an iron bolt that screws the whole together in the direction of its height. The ends are moveable, some-
times sliding in grooves, at others merely pinned in their place.
1167.
1166.
1171.
1168.
1169.
1173.
B
1170.
1175.
1174.
1177.
1172.
1176.
1179.
1178.
1181.
1180.
a
In the construction of all kinds of railway carriages, great attention should be paid to the centre of
gravity of the load, for if too high, their oscillation is considerably increased, which frequently occasions
them to be thrown off the rails, even where the wheels have the proper depth of flanch: the revolving
parts of the machinery in a carriage should be always so balanced that a smooth and equable motion
can always be maintained.
ECCENTRICS. See ENGINES. details of.
ECCENTRICS AND VALVE GEER See LOCOMOTIVE.
ELECTRICITY. All substances are susceptible in a greater or less degree of electrical excitation,
but according to their readiness to evince electric properties by friction, they are classed as electric or
non-electric. Electric substances have not only the property of electrical excitation, but also the power
of confining, or imprisoning, as it were, the communicated electricity upon other bodies, in which it could
not under the same circumstances be 80 excited while on the other hand, the non-electric substances al-
low the electricity to pass off. Non-electric substances, therefore, have been called conductors, and electric
substances, non-conductors or insulators. These expressions are merely relative, yet the difference in
conducting powers in certain bodies is enormous; that of iron, for instance, being estimated at 400,000,000
times greater than that of water.
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ELECTRICITY.
415
The following Table gives in an approximate way the order of precedence in conductive power.
Conductors.
Non-conductors or Insulators.
All known metals.
Ice at 0° of Fahrenheit.
Most perfect.
Well-burned charcoal.
Dried vegetable substances.
Plumbago.
Smoke.
Less perfect.
Dried animal substances, generally.
Burning gaseous matter, as flame.
Parchment, leather, feathers.
Baked wood.
Concentrated acids.
Oils and fatty substances.
Dilute acids.
Silk.
Saline fluids.
Fur and hair.
Less perfect.
Living animals.
Dry gases, including air.
Living vegetables.
Pure steam of high elasticity.
Wood, in its ordinary state.
Glass and all vitrefactions.
Snow, and ice from 32° to 0°.
Water.
Aqueous vapor.
Common earth and stone.
Imperfect.
Most perfect.
Diamond and transparent gems.
Talc.
Amber.
All resins and resinous bodies.
Dry chalk and lime.
Brimstone.
Marble and porcelain.
Shell-lac.
Paper.
Alkaline matter.
The effect of the electrical discharge on metallic bodies is to raise their temperature to a less or
greater degree, according to their conducting power.
The ratios of heat evolved, and of those of conducting power, are shown as follows:
Heat evolved. Conducting power.
Silver
6
120
Copper
6
120
Gold
9
80
Zinc
18
40
Platinum
30
24
Iron
30
24
Tin
36
20
Lead
72
12
Vitreous and Resinous, or Positive and Negative Electricity-There are two opposite electrical or
elementary states of excitation, in which forces are developed attractive of each other. These forces
were, by more early inquirers, supposed to depend on two different kinds of electricity, termed vitreous
and resinous, as being derived the one from excited vitreous bodies, the other from excited resinous
bodies. Subsequent investigations have shown that both these electrical elements may be obtained
from the same substance; bence it has been agreed to designate these opposite states by the common
positive and negative signs of arithmetic and algebra, calling the vitreous excitation, as developed in
the friction of glass by silk, positive or +, and the resinous, developed similarly by the friction of
resinous bodies, negative or - Substances in dissimilar states of electricity, that is, the one + and
the other -, attract each other; those in similar states, that is, both + or both -, repel each other.
If an insulated body A, charged, for example, positively, be placed near another body B, insulated,
but in its natural state, this latter body B, while in this position, will be found in an electrified state; the
portion nearest the charged body A showing a negative electricity, and the portion most remote a
positive; or vice versa, if A be charged negatively. This influence has been termed Electrical Induction,
and the resulting effect Induced Electricity.
The expressions of the most important electric laws are as follows:
The attractive force between two opposed surfaces varies—
If between a charged and a neu-
directly, as the square of the quantity of electricity,
tral free conductor,
inversely, as the square of the distance,
64
"
"
"
surface,
If between an unchangeable posi-
directly, as the square of the quantity of electricity,
tive and negative surface,
inversely, as the distance.
The conducting powers of different rods of the same metal vary therefore in a higher ratio, apparently,
than as the surfaces, though they are not asserted to do so as the squares.
They vary inversely as the length; and directly as the square of the diameter of the solid rod.
The heating effect (referring to solidity) varies directly, as the square of the quantity of electricity
inversely, as the area of the transverse section; inversely as the length of conduction.
Having thus briefly stated the general principles and laws of electrical action, omitting electric-
machines, electroscopes, &c., as being connected rather with scientific investigation and experiment, we
proceed to the practical applications or examples of power which electrical knowledge has supplied.
Lightning-conductor-1 first and most obvious practical result of Franklin's discoveries was the
lightning-conductor for the protection of buildings and ships from the violent effects of the disruptive
discharge. The first lightning-conductors consisted merely of metallic rods or chains proceeding from
the highest point of the building or the ship, in a direct line to the earth or to the sea; but this was not
found in all cases sufficient. Instances have occurred in which the conductors have been fused or
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shattered, and hence arose a prejudice against their use, under the idea that they did more harm than
good, by inviting the destruction they were intended to prevent. An attentive examination, however,
of numerous cases of damage from lightning has shown that the path of discharge from the cloud to the
earth is always in the line of least resistance. This line may not be the shortest lineal distance, but it
is in all cases the shortest electrical distance; that is, the lightning picks out the best conductors in its
transit to the earth, selecting with the nicest discrimination metal cramps and fastenings, and by its
expansive power shattering and destroying inferior conducting substances, such as wood, brick-work,
and stone.
The following diagrams from experiment, illustrate this principle fully:
Figs. 1182 and 1183. The shaded part shows the direct track a a
1183.
1182.
taken by the electric fluid along a line of metallic conduction,
disregarding every thing but its own course. Fig. 1182 may
a
represent the conducting masses in a building. Fig. 1183, the
passage of the fluid across the bight of a wire-rope, or of a chain.
Hence the principal danger in using chain or wire conductors in
the upper masts of shipping, as when these last are lowered they
are apt to leave the chain or wire-rope hanging loosely; and
when handling this as a bight, the seaman's body becomes the
shortest course (a' a', Fig. 1183) for the electric action, on the very
same principle that a metallic rod-conductor of proper dimen-
sions may be passed through a barrel of gunpowder with perfect
safety, though a chain would ignite it at once.
To guard effectually a structure from the stroke of lightning.-
First: The conductor should be of metal, and one of the best con-
ducting metals should be selected. Second: The conductor should
be capacious. Third: The conductor should consist of several
branches with pointed rods projecting freely into the air from
distant summits of the building, and connected by horizontal
branches passing along the ridges, and from these sending off
other branches to the ground.
1.
Copper is the best conductor the rods should not be less than
half an inch diameter, if solid; three-fourths of an inch is preferable, and generally ample. If hollow,
they may be from 1 to 2 inches in diameter, and about one-fifth of an inch thick.
If iron rods be used, they should not be less than three-fourths of an inch diameter when solid it
hollow, not less than 2 inches diameter and three-tenths of an inch thick, and jointed.
The hollow conductor (if sufficiently thick for stability) is better than the solid rod of equal length
and weight, because the metal should display as much surface (in lateral dimensions) as possible con-
sistently with strength, to reduce the intensity of action on surface, and heating effect in transverse
sectional area but unnecessary length should be avoided.
The conductor should involve in its course the principal detached masses of metal in or on the actual
walls and framing of the building or ship: if not allowed this course freely, it will be apt to take it in
a summary and violent manner. Figs. 1188 to 1192.
It should be placed as close as possible to the walls, &c., which are to be defended,-not at a distance
from them and should be carried down at once directly into the ground; and when below the surface,
it should then divide into two or more pointed branches a a a, Fig. 1187, slanting away from the building.
If circumstances permit, the lower end should pass into a well, or a stream, or a drain, or at all events
into earth that can generally be kept moist from any neighboring gutter. It is a useless precaution to
pass condctors through glass linings and holdfasts, as has been recommended, since the lightning will
always take the direct course down the rod until interrupted; on which last account chain conductors
are very inferior to those of rod, being a series of interrupted conductions from which the lightning is
ready to turn aside at any point of contact of the links,-provided that at such point a freer and easier
line of conduction be offered by some neighboring body than what the chain itself affords.
The conductor should be attached to the most prominent points of the building, Fig. 1190: if its
length be very considerable, its transverse dimensions must be increased; and in doing this, the
provision for a sufficient conducting surface insures that for the heating effect.
In ornamental buildings, such as honorary columns, &c., for the sake of appearance, the conductor
may pass down withinside; it must, however, be firmly fixed, and the line of conduction made and kept
complete and undisturbed.
In extensive ranges of buildings, all the most prominent points should have long pointed rods pro-
jecting freely into the air, at least 4 or 5 feet above the building; and the larger the range the higher
they should be. Fig. 1190.
It does not appear that any single conductor hitherto made can insure beyond a horizontal radius of
40 feet hence, in practice, less should be taken; though a wider range may be allowed if the roofs be
of zinc, lead, copper, or any other metal in well-connected sheets or if the ridges and hips only be thus
guarded, and the whole well joined to the conductor, and to iron gutters and pipes, now coinmonly
used, and a free passage be provided to the ground at different places. The points of contact must be
numerous, to reduce the heating effect (or chance of fire) at such points, as the whole electric action will
condense there, having still to pass through them on its way down. There is no reason why lightning
conductors should not be painted or lacquered.
In addition to the diagrams given in Figs. 1184, 1185, and 1186, showing the construction of hollow
conductors for buildings,-those for the protection of shipping, Figs. 1189 to 1192, are likewise noticed,
as probably providing for the most complicated cases that are likely to occur in the most extreme cases
on land.
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Fig. 1184, the mode of joining two lengths of copper tube ab by means of a double screw c with a
shouldered collar d.
Fig. 1185, the staple a, by which the conductor is supported at the joints and fixed to the wall.
Fig. 1186, the head of the conductor.
Fig. 1187, conductor complete, showing the lower termination a a a as buried in the ground. or re-
ceived in water.
Fig. 1188, application of conductors; the points
1184.
1188.
abcde, &c., connected by bands of metal dt
b
k, &c., into one general whole.
1185.
Fig. 1189, ships' conductors, consisting of two
strips of sheet-copper, from 1.5 to 5 inches
n
wide, and from 1-8th to 1-16th inch thick, in
1186.
lengths of 4 feet. They are let double into a
d
groove in the mast, 80 as to insure continuity of
conduction by breaking joint, as shown in the
figure: these strips are kept in thorough con-
tact, and are secured to the mast by copper nails,
6 inches apart, in the drilled and countersunk
1189.
holes a a. The upper surface of the upper piece
1187.
A A is slightly rounded, so as to conform to the
surface of the mast in transverse section.
Fig. 1190, the cap a b and the hole b through
which the moveable mast x slides, are furnished
with similar plates; these are led from the square
1190.
hole at a, by which the cap ab is fixed to the
head of the mast D, into the round hole at b;
1192.
and there is a lining of copper in this part of the
hole next to the conductor at b, by which the
D
metallic line is continued to the next mast D.
Figs. 1191, 1192, the bolts a passing
through the ship, and in which the general line
of conduction terminates, are clenched upon me-
1191.
tallic rings and plates, in connection with the
copper sheathing; and there are additional bands
mn, Fig. 1191, leading from the fore-inast and
mizen-mast directly to the stem or stern under
A
the decks; other bands gh, Fig. 1192, traverse
the beams, and they all terminate in the sea by
bolts clenched on the copper sheathing. Fig.
1192 is a section suited to the beams abaft each
mast.
Voltaic blasting.-The property of the electric current to raise the temperature of the metal through
which it passes, has been turned to account in promoting the efficacy and lessening the danger of blast-
ing on land and under water. Voltaic electricity is transmitted through a complete circuit, either wholly
or in part of metallic wire, and such an arrangement is adopted that a small portion of the circuit may
be rendered red-hot within the powder composing the charge. The object is attained by employing a
voltaic battery of sufficient intensity to heat a short length of fine steel or platinum wire fixed across
the disconnected ends of the conducting wires within the powder. Upon the area of the section of the
conducting wires and the intensity of the battery, depends the power of the electric current to travel
the required distance and produce the proper effect.
The principle of voltaic action may be thus stated let Fig. 1194 be a glass vessel containing a liquid
and a plate of copper C connected with a plate of zinc z, constituting a pair of a voltaic pile.
When the liquid is water alone, there is scarcely any electrical action. When salt is added, the ac-
tion becomes evident; but when sulphuric acid is added, it is very greatly increased a decomposition
of the fluid in this case takes place; the oxygen is taken up by the zinc, which has the greater affinity
for oxygen, and is therefore called the positive metal; the hydrogen is evolved at the negative metal,
copper. A current of electricity is thus generated.
Several positive and negative plates immersed in an acid solution, and connected one with the other
in a series, constitute a voltaic battery, which is more or less intense, according to the number of plates.
Various forms have been given to the voltaic battery, and modifications made from time to time, ac-
cording to the purposes to which it was to be applied.
Description of batteries that may be employed in blasting.-The common copper and zinc plate bat-
tery may be thus described. The pairs or sets of plates composing the series are each composed of a
zinc plate 3-16th inch thick in the centre of a rectangular case of sheet-copper, without top or bottom, a
convenient size for which may be 10 inches long, 1f inch wide, and 8 inches deep. The zinc plates
must be about 4 inch shorter than the copper case, so that the edges of the metals may not be in con-
tact: two slips of wood with grooves in them should be fixed, one down the inside of each end of the
copper case, and nailed by small copper nails: the zinc plates will then slide up and down in these
grooves, which will be found convenient in withdrawing them for cleaning, and will keep them separate
from the copper. The connections may be formed by bands or strips of stout sheet-copper 1 to 4 inch
wide, riveted to the zinc plate, and soldered to the copper case: there should be two connections to
each set of plates, fixed at a few inches from their ends. Binding-screws should be used for connecting
the strips of metal in sequence above the plates thus: let the 1st zinc form the terminal plate or nega-
43
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tive pole of the battery: this must be disconnected from any other the two strips of metal on the 1st
copper case will then be turned over, and connected with the two on the 2d zinc plate, the two on the
2d copper with the two on the 3d zinc, the two on the 3d copper with the two on the 4th zinc, and 80
on up to a series of ten or twelve, which will be found sufficient for any common mining purposes. The
last copper case will then be found to stand free as a terminal plate or positive pole. Two stout cop-
per wires, let into these terminal plates, will form the poles, on connecting which the circuit is complete.
The sets of plates must all be let into a stout frame 2 inches X 11 inch, for the purpose of immersing
the whole simultaneously into the trough or cells containing the acidulated solution, which should con-
sist of dilute sulphuric acid, in the proportion of 1 of acid to 10 or 12 of water. This trough should be
either of oak or elm baked, as it then becomes a very imperfect conductor of electricity. There must
be as many cells as sets of plates, which should be from 11 inch to 2 inches wide, and 9 inches deep.
The partitions separating them should be about f inch thick; the whole made water-tight by being
coated with a cement, for which the following ingredients have been found by trial to answer the best,
viz.:
Spirits of wine
I gal.
Gum Sandarach
2 OZ.
Shell-lac
1 lb.
Vermilion
t lb.
The above quantities and proportions will be found sufficient for covering the inside of the trough of a
battery of 10 cells with 2 coats, containing about 23 superficial feet each.
The partitions to the cells are necessary in a battery of this form, to keep each set of plates separate,
otherwise the fluid acting as a conductor would cause a cross play of electricity between every positive
and negative plate in metallic connection, and much power would be lost.
In lieu of the connections by bands or strips of sheet-copper, a convenient form of uniting the copper
case and zinc plate will be by leaving a tongue or flap projecting from one of the upper edges of the
former, and extending its whole length, sufficiently broad to be turned over at right angles, and again
bent upwards 80 as to come in contact with the adjoining zinc plate the whole of the upper edges of
the two metals will thus be in metallic contact, by which increased contact some additional power will
be gained: in this arrangement the zinc plate must stand higher than the copper case by about the of an
inch, so that the flap of copper may be quite clear of the case next to it: the end or terminal plates
may be finished with triangular flaps, and the wires for forming the poles may be connected to the apex
of each triangle.
This constitutes a common plate battery, which, for mining operations, will be found sufficiently pow-
erful from the very short time required to keep it in action for heating platinum wire. But it has many
defects. The acid speedily becomes saturated with oxide of zinc, by which its conducting power is
reduced. The hydrogen which is set free at the negative copper plate adheres with great tenacity to
its surface, and throws a considerable portion out of action: it reduces the zinc from the solution, and
deposites it on the copper plate, by which a zinc plate is virtually opposed to a zinc, and a counter-
action is thus produced; and in addition to this, the zinc of commerce, being exceedingly impure, con-
tains many particles of foreign matter which unite in consuming the zinc, and in causing what is called
local action this latter evil is however somewhat obviated by the amalgamation of the zinc plates
with mercury.
Daniell's battery.-A single cell of this battery consists of a copper cylinder, an amalgamated zinc
rod, and a porous diaphragm, which may be composed of various materials, such as paper, plaster of
Paris, sail-cloth, porous earth, or animal membrane. In this arrangement two fluids are used, separated
by the diaphragm, containing dilute sulphuric acid in the proportion of 1 of acid to 8 of water, in which
the zinc rod is immersed on the outside of the diaphragm, next the copper cylinder, is a saturated so-
lution of sulphate of copper, containing a little sulphuric acid binding-screws and stout wires are used
to connect the respective metals with each other. The zinc being well amalgamated, and the apparatus
in perfect order, no electrical action will take place until the circuit is completed by the wires, when it
will be indicated by a sharp and clear spark emitted at the poles: this action, however, takes place
without the evolution of hydrogen at the negative metal; in lieu of this, copper will be released from
its sulphate, and deposited on the copper cylinder; the strength of the solution must therefore be kept
up by a supply of the crystals of the sulphate of copper, which should be continually dropped in for
the purpose of being dissolved. The advantages of this arrangement are, that the hydrogen, not being
evolved at the copper cylinder, the formation of the film or coating of this gas is avoided, which has
been shown to be so prejudicial to constancy of action in common plate batteries: on the contrary, a
deposite of pure copper is formed, and the deposition of zinc upon the copper is avoided. The limits of
the duration of the action are, the exhaustion of the copper solution, and the saturation of the acid solu-
tion within the diaphragm, joined to the consumption of zinc. The action may be prolonged for a very
long period, (8 or 10 hours.)
Zinc and iron plate battery.-Within the last few years, iron has been much used as the negative
metal for plate batteries. Its being more economical than copper was probably the principal reason for
its being first adopted, but it is also superior in other respects. When the battery is in action, the
hydrogen of the decomposed fluid does not adhere to the surface of iron as it does to copper, which has
already been shown to cause great loss of power.
The arrangement of a battery of this form would be similar to the common one, viz. a single zinc
between two iron plates: ten or twelve of these sets would be sufficient for a battery for common pur-
poses. The iron plates should be cast as thin as possible, to diminish the weight; 3-16ths of an inch is
a good thickness. The connections of the battery may be formed by strips or bands of sheet copper,
1 to 1 inch wide, riveted to the iron and zinc plates, one on each of the former, and two on the latter,
connected by binding-screws: to observe regularity in forming the connections down the series, and to
avoid confusion, the width of the battery should be divided into five equal parts; then the connections
of the first set of plates may be riveted to them, at the first and third divisions; of the second
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419
the second and fourth divisions; of the third, at the first and third; and so on alternately this will
preserve regularity, and keep all connections clear of each other. This difference in connecting the cop-
per and iron plate batteries is caused by the former being one single case, the latter two separate plates,
each of which has to be connected to its adjacent zinc.
A convenient dimension for the plates will be about 10" X 8"; they should all slide in grooves, cut
out of upright pieces of wood let into the frame: any plate may thus readily be withdrawn, if required.
The plates should be supported by leaving about 1 an inch at the bottom of each groove solid or uncut,
which will form a shoulder for them to rest upon, and they will thus be about 1 an inch clear of the
bottom of the trough.
The acid solution should be of the same strength as for the copper plate battery already mentioned.
The dimensions of the trough for a battery of ten sets of plates will be about 2' 2" X l' 1" X 10",
each cell being 111 inches long, 2 inches broad, and 9 inches deep.
A plate battery should always be raised or suspended above its trough when not in action, to allow
the acid solution to drip from the plates into the trough; and this may be done in various ways, either
by having ends or handles projecting beyond the frame for lifting the battery in and out, or by stand-
ards attached to the ends of the trough, carrying a windlass, with handles for winding the battery up
and down by means of a cord attached to each end of the frame; and which may be rendered still
easier to work, by having weights to counterbalance the battery suspended over small pulleys on the
standards; or, lastly, by having a cog-wheel and rack inserted in each end of the frame, with handles
for turning the wheels.
A plan for constructing the iron and zinc battery has lately been adopted in Scotland, which possesses
some advantages over the one above described, in which the trough is simply a box without partitions:
a battery on this principle becomes very compact, as the plates may be much closer to each other than
in any other arrangement: the action of both sides of the plates is also thus obtained. In this construc-
tion the zinc and iron plates are placed alternately, in lieu of having one of the former between every
two of the latter: supposing the series to commence with iron, let the first and second iron plates be
connected together as a double terminal plate, with a wire attached to form the positive end or pole;
then join the first zinc and third iron, the second zinc and the fourth iron, the third zinc and the fifth
iron, and so on to the end of the series, which may consist of twenty plates of zinc and twenty-one of
iron; then it will be found that the twentieth or last zinc will be disconnected from any other, and a
wire attached to this will form the negative end or pole.
In this construction the plates may be very close to each other, about t of an inch apart; they should
be separated by slips of wood of this thickness, placed between each plate, the whole being kept to-
gether by two pieces of board at the ends, connected by cross-bars at the sides, and with one at the
bottom to prevent the plates from falling out: this arrangement will be found simple and expeditious,
and therefore well calculated for common blasting operations. The partitions in the trough may be dis-
pensed with, because by the method of connection, two plates intervene between every pair in metallic
connection; there is thus no cross play of electricity. The action of both sides of the plates is also thus
obtained. A battery of twenty pairs, or of forty-one single plates, may be readily got into a space of
20 inches in length, or even less.
This last mode of arrangement is recommended for blasting operations in the field, from its compact-
ness and simplicity of construction: the power of a battery of this form would be about on an equality
with one of a similar number of plates on the common principle, and a single battery would be sufficient
-
to fire charges at the distance of 500 feet if more power should be required, then two of them may be
combined.
Grove's battery.-Its peculiarity consists in the use of two acids-concentrated nitric and dilute sul-
phuric or muriatic the former is contained in an inner porous cell in contact with platinum, the nega-
tive metal; the latter in an outer vessel with zinc, the positive metal. As soon as the electric current
is established by completion of the circuit, both acids are decomposed; the hydrogen of the muriatic
unites with the oxygen of the nitric, and the chlorine attacks the zinc. The hydrogen is thus removed
without being evolved at the negative plate.
This battery is remarkable for its power: a series of four cells in good order will give a cubic inch of
mixed gases per minute for every square inch of platinum in each cell, and all the other effects in pro-
portion. It has also the advantage of occupying very little space. It is remarkably constant, and, from
its great intensity, very economical, as a smaller series may be employed than in any of the other com-
binations.
For mining and blasting operations on a large scale, its great intensity would make it valuable, par-
ticularly in firing a number of charges simultaneously; but for common purposes of this kind it would
perhaps not be 80 practically useful as the simpler form of the zinc and iron battery already mentioned,
the porous cells being fragile and delicate, and the nitric acid destructive to clothing.
Smee's battery.-Another battery of great practical utility has also been invented by Mr. Smee, who
has taken advantage of the property which roughened surfaces possess of evolving the hydrogen, by
covering the negative element, either silver or platinum, (generally the former for practical purposes,)
with the finely divided black powder of platinum it is not, however, considered necessary to enter
more fully into the construction of this battery. The relative power of batteries is indicated by the
number of degrees of deflection of the galvanometer.
The principles of several kinds of batteries which may be usefully employed in blasting having been
given, it should be again remarked that the cast-iron and zinc battery will be found the most practically
useful, and the simplest form will be that in which the zinc and iron plates are placed alternately, and
the action of both their sides is obtained; the trough being simply a box, without being divided into
cells.
Of the conducting wire to be used in blasting.-The best conducting wire consists of several fine copper
wires twisted together like a hempen rope: as it is very flexible, less liable to break than a solid wire
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of equal dimensions, and the junctions of the several lengths may be very securely united by splicing,
as in a common rope. The conducting power of wires varies with their thickness, or with the area of
their section this should not be less than one-fifth or one-sixth inch in diameter, and in forming the wire-
rope as many fine wires must be twisted together as will make up this size. During the operations on
the wreck of the Royal George, the wire-rope was prepared in the rope-house at Portsmouth Dockyard,
out of wire 1-10th inch in diameter, or No. 14 gage; three strands or threads being a little more than
equivalent in area to one solid wire one-sixth inch in diameter: 30 lbs. in weight of this size, or 1000
feet in length, made 300 feet of conducting wire when completed.
To insulate the two conducting wires from each other,-which for the sake of convenience and porta-
bility should, in land operations, be laid close together, 80 as to form, as it were, one rope,-they must
be carefully coated with a water-proof composition, and then bound over with layers of tape, twine, &c.,
making them, when thus prepared, about fth inch in thickness. The composition which has been
hitherto generally used for this purpose consists of beeswax, pitch, and tallow, in the proportion of 8
pints of pitch to 1 of each of the other ingredients, laid on while hot.
In forming conducting wires, they have hitherto generally been separated or insulated by being laid
on each side of a 4-inch rope placed between them. This rope may, however, be dispensed with, and
for land operations, the wires having been carefully coated in the manner described, may be laid close
together, side by side, and then bound over or connected by coarse tape or twine. The double conduct-
or thus becomes small and of convenient size.
For subaqueous operations, in using a double wire it will be better that the two wires thus prepared
should be employed separately or singly rather than joined together as one; for, in working under wa-
ter, much inconvenience and loss of power result from the covering becoming gradually worn off by
damp and friction, leaving the wires exposed in one or more places and in contact with the water, and
failures are frequently caused from the wires being brought together at an improper place, causing the
circuit to be completed before arriving at the charge. The two separate single lines may each be con-
nected to one of the priming wires of the charge at one end, and to the poles of the battery at the other,
and a large space left between them intermediately; then all risk of a failure from improper metallic
contact would be obviated.
But in subaqueous operations, a complete metallic circuit is not required a portion of one of the con-
ducting wires may be dispensed with, and the depth of water intervening between the charge at the
bottom and the surface of the sea or other piece of water in which the operations are being carried on,
may be used for completing the circuit. In this case, on account of water being a more imperfect con-
ductor than that portion of the wire for which it is substituted, it becomes necessary to use a larger
surface of metal at each extremity of the water conductor, that is to say, (in the case of submarine oper-
ations,) at the bottom and surface of the sea, to lead the electric fluid through it. At Spithead, in the
summer of 1843, we used zinc plates at the surface, and the case of tin or iron in which the charge was
usually contained served as the metal required at the bottom. At the depth of 18 fathoms it was as-
certained that about 3 square feet of surface of the zinc or positive metal was required, but in respect
to the other, or negative metal, a much smaller surface was apparently sufficient. This surface of zinc
should be divided into three or more plates, connected with each other and suspended from a copper
wire passed through a hole in the top of each plate, and immersed into the water at the surface the
other end of this wire goes to the battery. The long single wire extending from the battery to the
charge is connected to one of the priming or short wires inserted in the bursting tube, and the other
priming wire is turned down on the metallic surface of the case enclosing the charge, and connected
with it. The charge having been taken down by a diver, and placed in its proper position at the bot-
tom, the ends of the long single wire above water, and of the short length attached to the plates, are
led to the voltaic battery on forming contact at which, the intercepted portion of the circuit from the
zinc plates at the top to the metal case at the bottom of the sea is completed by the depth of water
between them the electric current is thus passed through the piece of fine platinum wire fixed across
the priming wires of the bursting charge, which also forms a part of the circuit, and is instantaneously
ignited. This method will serve when the charge is contained in a vessel of tin, iron, &c.; but in the
case of wooden casks it would be necessary to attach a sheet of tin or copper to the surfaces of the cask,
to which the second priming wire would be attached.
Description of the charges usually employed in voltaic blasting.-It has already been stated that igni-
tion is communicated to the charge by having a small portion of the circuit within the powder composed
of fine steel or platinum wire, (about 1 inch in length,) which, being made red-hot during the transmis-
sion of the voltaic current, fires the charge as soon as contact is made at the battery.
From the rapidity with which the fine wire is fuzed, it is necessary that the powder immediately in
contact with it should be of a finer quality and more thoroughly dried than the main body of powder
composing the charge. On this account, and for the sake of convenience in attaching the main or con-
ducting wires, it is usual to have small bursting charges, or cartridges, holding a few ounces of the finest
sporting powder, (their size varying according to that of the mass of powder to be ignited,) which should
be thoroughly dried by being placed and shaken on a plate which has been moderately heated at the
fire. These bursting charges may be contained in cylinders or cases of tin or paper; if in the former,
great care is required to prevent the wires within the case from touching the tin, on account of its being
a conductor. For land operations, it will merely be necessary to close the top and bottom of the burst-
ing charge with bungs of cork; before fixing which, the priming wires (so called to distinguish them
from the main or conducting wires) should be introduced, from a foot to 18 inches long, the ends pro-
jecting 9 or 12 inches from the top of the case, the ends within it passing through grooves cut into the
sides of the upper cork, and clenched against a thin piece of wood near the bottom of the bursting
charge, but not occupying the whole of its interior space. The platinum wire should be fixed across
the copper wires about the centre of the bursting charge, which should then be filled from the bottom
with the finest sporting powder, and closed by the lower bung of cork. The top and bottom of the
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bursting charge should then be sealed with any good cement, which does not crack in cooling, and will
keep out damp.
In firing a mine on land, it will be necessary to place a bursting charge, prepared as above, in the
centre of the mass of powder to be ignited; the ends of the main conducting wires must then be con-
nected with those of its priming wires by placing a few inches of each, side by side, and frapping round
them with fine bell-wire, and then covering them with tape dipped in water-proof composition. The
length of the conducting wire must of course vary according to the nature of the mass to be removed by
the explosion, the splinters from which, if of rock, might endanger the operator at the battery, unless at
a considerable distance from the charge. In mining operations on a moderate scale, a length of from
300 to 500 feet will generally be found sufficient for conducting wires, and for which the battery of ten
sets of plates will possess sufficient energy. Contact may then be made at the battery by hand and
from the rapidity with which electricity travels, the firing of the mine takes place at the instant the cir-
cuit is completed: should it be feared, however, that at this distance splinters might injure the person
firing, a self-acting apparatus may easily be contrived by which he may retire to a place of safety, after
having made the arrangements at the battery to insure the circuit being completed a minute or two
after he has left it.
Such a self-acting apparatus may be formed by means of mercury in a cup or vessel, having one end
of the conducting wire dipped into it while the pole of the battery to which it is to be connected is
suspended above it, and held by a string; (the end of the other conducting wire and pole of the battery
having been previously connected.) If such an arrangement therefore is adopted as to cause this string
to be burned asunder in a given interval after the operator has left the battery, so that the pole of the
battery may drop into the same cup of mercury as that in which the end of the conducting wire to
which it is to be connected is already immersed, the object is gained; for by means of mercury as good
a connection is formed as if the ends of the wires actually touched each other.
Another method by the agency of mercury has been recommended by Professor O'Shaughnessy,
thus. Fig. 1193
c c'. Conducting wires.
P W. Platinum wire.
1193.
pp'. Poles of battery B.
e.
V. Vessel filled with mercury, and with a cock at
bottom for emptying it: the conducting wires c c' pass
through holes in the sides of the vessel.
As long as the vessel is full, the circuit of the conducting wires will be completed by the mercury,
and the electric current will thus be stopped from passing through the piece of platinum wire, P W;
but on opening the cock below, the mercury will descend, and as soon as a sufficient quantity has run
out to leave the conducting wires clear, the current will no longer be stopped, but will pass through the
secondary wire P W and ignite it. Therefore a sufficient quantity of mercury should be left above the
level of wires c' to allow a person time to get out of danger, after having turned the cock and made
the arrangements for firing the charge.
In preparing the blasts for being fired by the voltaic battery, wooden cones may be used immediately
above the charge; the priming wires should be let through a groove cut on each side of the cone, their
ends turned down on the bottom of it, and connected by a piece of fine platinum wire from 1 inch to 11
inch long. If in a dry soil, the powder may then be enclosed in a canvas bag, tied round a projecting
collar on the bottom cone; the come and the charge with its priming wires may thus be let down to the
bottom of the hole, and the tamping of broken stone made over it. The priming wires will, of course,
vary in length according to the depth of hole; they should project about 12 inches above the top of it,
and the conducting wires may then be connected to them, as above described. If in a damp or wet
situation, the bag must be coated and made water-proof, or the charge may be contained in a case of
brown paper or pasteboard, pitched over.
For mines of a moderate size, which do not contain more than from 50 to 200 pounds of powder, the
bursting charges may be small; the cartridge being altogether about 4 inches long and 1 inch in
diameter, and holding about'l ounce of fine powder.
In operations on a larger scale, these secondary charges may be proportionably increased in size, and
even two may be used on each conducting wire, to be fired simultaneously, so as to ignite a large mass
of powder in two places at the same instant: this was successfully adopted in firing the great mines at
the Round Down Cliff, Dover, in January, 1843, where for the three charges (two of 5,500 pounds, and
one of 7,500 pounds) there were two bursting charges on each conducting wire, 9 inches long and 2
inches diameter, which were extended to a distance of about 3 feet apart in the chambers, and buried in
the centre tier of loose powder. In this operation the powder was contained in loose bags, holding
about 50 pounds each, the mouths left open, and uppermost in the. tiers below the centre, while those
above it had the mouths downwards the interstices were filled in with loose powder. This will be
found a convenient mode of charging mines, and will insure the ignition of the whole of the powder
when in large masses.
On the preparation of charges for subaqueous operations.-The preparation of these charges requires
the greatest care, particularly when the operations are carried on at any great depth.
In working against a wreck, the general system will be to employ large charges at first to break it
up into detached masses, which if necessary may again be subdivided by using charges of a smaller
size, until at length very small quantities of powder will be sufficient to break up or detach the pieces
still remaining. Hence the sizes of the charges will vary according to the objects for which they are
required. For containing the larger charges, which are supposed not to exceed 600 or 700 pounds, wine
or spirit casks will be found convenient and economical; and if the depth does not exceed 30 or 40 feet,
they need not be stronger than those commonly used in the navy, excepting that the heads will require
some additional 8 curity, as being the part most liable to be forced in by the pressure of the water.
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Beyond that depth, however, the whole cask should be more strongly made than would be usual for
common purposes.
A convenient size of cask for the larger charges will be the 72-gallon puncheon; for the medium size,
the 18-gallon cask; and for the small ones, tin cans or oil-bottles, of sizes varying from 2 to 5 gallons.
The puncheon for the larger charges, when sunk to depths of from 10 to 12 or 13 fathoms, should be
prepared as shown in Figs. 1228 to 1230; the body or staves to be 11 inch thick, and the heads formed in
two thicknesses of 11 inch each, the lower one placed transversely to the upper, and resting on a circular
groove or shoulder cut out all round the inside of the ends of the staves, equal in depth to about half
their thickness. This lower head should be additionally secured, both at top and bottom, against external
pressure, by the support of four cleats, to be let at equal distances round the circle about 1 inch into
the thickness of the body. The upper head should be fixed close over the lower one, and secured to it
by strong 3-inch screws; it should come flush with the outside of the cask, and a broad iron hoop passed
round outside the top and bottom, screwed to each of the heads, will secure and connect the whole firmly
together. Where these or similar precautions are not adopted, there will be every probability of the
heads being forced in by the pressure of water above, which, on a head 2 feet in diameter, at the depth
of 13 fathoms, would be about 7 tons.
In altering common puncheons for subaqueous explosions, it would be necessary to saw off so much of
the top and bottom as would include the triangular groove or mortise into which the common form of
head is usually let; then the rebate or shoulder for the new head should be commenced from that level.
The most difficult and troublesome part of the operation will be that of making the cask water-proof;
for when sunk to a great depth, the pressure of the water would cause it to penetrate at the most
minute hole or imperfection in the covering. The cask is first to be payed over with a coat of the
composition above mentioned, consisting of beeswax, pitch, and tallow, which will fill up the pores of
the wood, and, with the addition of strips of canvas laid between the hoops, will bring the whole surface
level, and prevent their edges from chafing the coats of canvas to be next laid on, which should consist
of strips (No. 6, good old worn canvas will do) laid on lengthwise, from end to end, having been pre-
viously coated with composition on the under side only; the ends, projecting 5 or 6 inches beyond those
of the cask, should be notched for the purpose of folding or plaiting down upon the circular heads: the
joints of the canvas should not lap over each other, but merely touch; 5-inch slips are to be laid over
each joint previous to the second coating, in which the canvas should be laid in a transverse direction
to the first, encircling the cask with one joint round the centre or bung diameter, and projecting 4 inches
over the ends, which projections should be notched and plaited down on the heads as before. A 5-inch
strip must then be laid over the central meeting-joint, and each head covered with a circular piece equal
to its own diameter.
In both first and second coats, the composition should be laid on the under side of the canvas only,
and drawn through to the upper one by a hot flat iron; by this means the interstices and pores of the
canvas are entirely filled, and made water-proof. A coating of the composition should also be put over
the whole on completion
When in this state, the puncheon should be lowered empty to the depth at which the charge is
intended to be fired, and kept there half an hour, in order to test its strength and water-proof qualities;
and if proper precautions have been taken, the cask will not admit the smallest particle of water. In
lowering, it will be necessary to protect the canvas covering from friction of the slings in which it is
held, by fixing six or eight staves of casks tightly round the outside, lashing them at equal distances by
yarn, for the reception of which grooves should be cut in the staves, about 2 inches wide and I inch
deep, at about 6 inches from each end. The slings may then be passed over the staves, and kept quite
clear of the water-proof covering, and they should also be connected by rope-yarn to keep them from
slipping. After the cask has been drawn up, if found to be water-tight, it will be ready for loading and
for the insertion of the bursting tube, which may be conveniently formed out of lead pipe, with the
bottom closed, and a circular collar or flange formed on the top, projecting about } inch, for the purpose
of nailing on to the cask. The length of the tube should be a little more than half the bung diameter,
so as to enter the cask to about half its depth. For the 72-gallon puncheon a convenient size of tube
will be l' 6" long and 2 inches diameter; and for the 18-gallon cask, 12 inches long and If inch
diameter: a circular hole must be cut out of the cask, at its bung diameter, of sufficient size to receive
the tube which will be inserted, and the projecting collar nailed down on the surface by small clout-
nails. The operation of loading may then be commenced; the loading hole will be cut out of the centre
of one of the heads, tapering from the top to the bottom, where it should be about 2 inches diameter; a
cleat 20 inches long and 4 inches broad having been previously nailed on over the centre of the head,
which will thus make the thickness of wood at the loading hole about 31 inches. The puncheon should
be filled by inverting the small powder-barrels over the loading hole. As each barrelful is poured in,
the puncheon must be continually shaken, in order that the powder may be properly distributed over
the whole surface, and it should at the same time be rammed by a copper rammer. Nearly 10 pounds
of I owder per gallon may thus be got into the puncheon. As soon as it is full, a small wooden plug,
about an inch thick, should be dropped into the bottom of the loading hole, and the water-proof compo-
sition poured in above it, until nearly on a level with the top of the upper surface of the head. The
remainder of the hole within the cleat will then be closed by a dovetailed wooden plug, with a circular
head projecting about 1 inch all round, firmly driven in with composition, and just entering the upper
part of that already poured in; the whole should then be carefully payed over with the same.
The preparation of the bursting charge will be similar in principle to that described for land operations,
though differing somewhat as to its details. It is shown in Figs. 1227, 1228, 1231, 1232, 1233, where
1232 and 1233 represent a collar and plug, turned out of oak, elm, or beach. The collar is for closing
the top of the tube, into which its lower half should enter about half an inch, being made a little smaller
than the diameter of the tube, while the upper half lies on the surface of the cask, consisting of a flanch
or shoulder projecting half an inch all round. A circular hole is left in the centre of the collar, about 11
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inch diameter, through which the two priming wires pass, and their ends are received by the plug
below, which should be of a cylindrical form, varying in size according to that of the bursting charge.
For the 2-inch tube the plug should be about 11 inch diameter and 7 inches long, with two grooves I inch
square, cut in it opposite to each other, in which the wires are laid. The lower part of the plug should
swell out about half an inch for 1 inch in length, to give a projection for attaching the mouth of the
canvas bag containing the bursting powder. The ends of the priming wires are turned up and flattened
against that of the plug, and nailed to it with small copper nails. Two pieces of fine platinum wire are
then to be laid across the ends in small notches previously cut into them with a chisel, which should be
closed and hammered lightly down over the fine wire to retain it in place. This operation requires
great care from the delicacy of the platinum wire, two pieces of which are used as a precaution in the
event of one breaking. By means of the plug the priming wires will be kept firmly in their position,
and not be liable to move, which might cause a fracture in the fine wire connecting their ends. The end
of the plug should have a circular hole left in it, on each side of which the flattened ends of the priming
wires will lie, and being filled with fine powder in contact with the platinum wire, the ignition of the
latter and of the bursting charges will be insured. The canvas bag containing it will be about 7 inches
long, occupying the remaining length of the lead tube, and the vacant spaces round the sides and bottom
should then be filled with the composition, and circular layers of canvas, well coated and payed over
with the same, passed over the collar to cover the joint between it and the surface of the cask, and
carried up a few inches on the priming wires above the collar. The ends of these wires should project
about a foot beyond the top of the tube for connecting with the conducting wires, carefully insulated
with tape, yarn, and composition, as above described. In order to relieve the junction of the priming
and conducting wires from all strain, they should, when connected, be turned down upon the surface of
the cask, and fixed there by a lashing of rope-yarn, passed round it. In working in a tide-way, or in a
heavy sea, the strain would sometimes be considerable, and might be sufficient to cause the separation
or derangement of the wires, unless this precaution were adopted. It may here be stated, that by
having a bursting tube, the risk of the whole of the powder being spoiled in the event of the cask
leaking, is obviated; for as the water, if it penetrated at all, would most probably find its way through
at the joint which must necessarily be left round the collar and tube, and for securing which the greatest
precautions should be taken, the powder contained in the small charge only would, in such a case, be
damaged, the main body of powder still remaining dry and fit for use; the cask would therefore, in the
event of a failure from this cause, have to be drawn up again, and a fresh bursting charge inserted.
In lowering a cask containing a charge of the larger size (650 pounds) to be fired against a wreck, a
small tackle must first be used to raise it from the deck of the vessel in which the operations are
being carried on. After it is in the water it will be so well supported as only to require a line passed
round a bollard, and attached to the slings to lower away upon gently. To the end of this line a buoy
should be attached, to be thrown into the water for marking the position of the charge, so that on
heaving the vessel or vessels out of the way, they may be placed at a proper distance. Previous to the
explosion, in working at a depth of 13 fathoms, a horizontal distance of 80 to 100 feet will be sufficient
for safety in firing the larger charges, and about one-half that distance in firing the medium ones, while
for charges not exceeding 50 or 60 pounds, the vessels need not be moved away at all, but may remain
immediately over them. It should be remembered, however, that the effects will be much greater when
working at less depths, and the distances should be increased accordingly. The 72-gallon puncheon
will, when filled with powder, require a weight of 4 or 5 cwt. to sink it, which may be conveniently
given by attaching canvas bags filled with ballast, weighing about 1 cwt. each.
The description given for the preparation of bursting charges for casks will hold good for any
description or size of charge, the rule being that the bursting charge should be equal in length to half
the diameter of the vessel containing the powder; and the size of the collars, plugs, and canvas bags
will therefore be varied according to that of the main charge. Where the diameter of the plug becomes
small, as in the case of bursting charges for tin cases, its end should be cut obliquely, 80 as to offer n
greater surface for receiving the flattened ends of the priming wires, and to insure a length of 1 inch of
platinum wire, which should be its minimum length. For the tin cans, tubes of the same metal should
be used for the bursting charges, soldered into the cans, at about the centre of their height. It may be
remarked, that in working at such depths as 12 or 13 fathoms, the depth or height of water above the
charge becomes a very efficient tamping, and a considerable effect will be produced where charges are
merely laid on the surface at the bottom, for the purpose of forming a hole or crater below them, which
would be frequently required where the timber or other material to be removed is buried in a mass of
mud or shingle, which there is no other means of dispersing.
On firing a number of charges simultaneously.-This operation will be found of great use on land,
as well as in working under water, and more particularly in blasting rock in quarrying, where it is fre-
quently an object to throw down a long face of stone, and where a much greater effect may be produced
by the judicious disposition of several small charges in line with each other, than if the whole of the
powder were concentrated in one mass. The simplest and most economical mode of firing several small
charges or blasts on land, will be to have a main conductor consisting of the double insulated wire laid
parallel to the blast-holes, but several feet in rear of the face intended to be thrown down, so that the
wires may not be injured by the fragments falling after the explosion. To this main conductor will be
attached at the several intervals branch wires leading to the charges, its end being used for connecting
with the extreme charge. The connections should be very carefully formed by opening the main wires
at each point, and attaching the ends of the branch wires either by means of bell-wire or binding-screws,
(the latter mode will be most expeditious,) and taking care that the wires are well cleaned and
brightened at the several points of connection.
At short intervals of 10 or 12 feet, and with branches, which for small blasts need not exceed 20 feet
in length, a battery of moderate power would be sufficient for firing eight or ten charges simultaneously;
but it will be prudent in the first instance to fire a set of small cartridges in the same positions as those
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ELECTRICITY.
of the intended charges, to ascertain the requisite strength of battery, which may be increased to any
sufficient amount by combining two or three together. It is believed, however, that when the length of
the main conductor does not exceed 400 feet, and of the branches 20 or 30 feet, two batteries of ten sets
of plates each will be sufficient for a number of charges not exceeding ten or twelve. By this mode
of arrangement the charges may all be said to be fired at the same instant. Several interesting experi-
ments have been tried on this subject, which prove that each secondary wire becomes ignited, as it
were, at the same moment of time, and that no part of the effect is dependent upon their being
consecutively broken, as has been supposed; also that in the case of the non-ignition of one of the
secondary wires, (which might happen if the powder in one of the charges were accidentally damp,) yet
all the others would be ignited and their charges fired as usual. Again, if improper metallic contact of
the copper wires exists anywhere, either in the conductor or branches, the electric fluid would be stopped
from passing through any of the charges, but would return to the battery from the point of improper
contact without any effect; hence the greatest care will be required in connecting, to keep all main wires
clear of each other.
The above description applies chiefly to cases of common blasting, where the length of the branches
and their distances apart on the main wire would be small; but in operations on a larger scale, where
it may be necessary from local circumstances to have a great length of wire communicating with each
charge, it would be imprudent to attempt firing several charges simultaneously by a single combination
of batteries. A safer plan will be to have a battery for every two charges, or in some cases it might
even be better to have one for every charge; the circuit being completed either by hand or mechanically
by the mercurial igniter already noticed.
In forming the simultaneous contact of a number of separate wires, the mercurial igniter will be found
very convenient, which should consist of two parts. A stand or stool, about 18 inches high, with a front
frame containing as many cups or receptacles for mercury as there are wires, and an arm or cross-piece
hinged to the back of the stand, with a corresponding number of short pieces of stout copper wire let
into it, and suspended over the frame in such a manner that on being let down each piece of wire will
enter a cup of mercury below it; one pole of each battery, and the end of one side of each conducting
wire, being then connected to each other either by screws or bell-wire. The second pole of the battery
may be let into a mercury cup, and fixed there, while the other end of the conductor to which it is to be
connected will be attached to the piece of copper in the arm immediately above it. The same arrange-
ment being made for all the wires and batteries, it will only remain to let the arm fall down upon the
cups, when, the circuit being completed at the same instant by the upper wires entering the mercury,
the whole of the charges will be simultaneously fired.
Before attaching bursting charges to a conductor, it will be essential to prove that the circuit is
complete, and the platinum wire perfect; for being extremely delicate, this secondary wire is occasionally
liable to be broken in spite of all precaution. The readiest mode of doing so will be by means of the
instrument called the "galvanometer," the principle of which is founded on the well-known influence of
voltaic electricity on the magnetic needle.
Another mode of proving the completeness of a circuit by means of the water-test apparatus," or
the power of the electric circuit to decompose water, may also be used, but it will require a more
powerful battery, and not be 80 quickly performed as by the galvanometer, by which 100 cartridges may
be proved in less than half an hour. In carrying on operations of this kind, it will also be occasionally
useful and interesting to try the relative power of different kinds of batteries and lengths of wire, for
which purpose the voltameter or decomposition apparatus may be employed, which is constructed 80
as to measure off the quantity of gas emitted when water is decomposed, and thus to indicate the
amount of electricity passing in a circuit.
There are various forms of voltameter, but the one most commonly employed, and which would give
the most accurate results, is that in which the water (slightly acidulated) is contained in a glass vessel
of moderate size, closed at the top, into or near the bottom of which are fixed two pieces of platinum
wire about one-quarter of an inch apart. A glass tube, whose interior diameter may be half an inch,
graduated to cubic inches and parts, is supported over these poles, entering the water to some depth.
The tube being also filled by inverting the vessel, the mixed gases will be collected in it on connecting
the ends of the wires or poles of the battery with those of the voltameter, and by keeping a record of
the quantities of gas delivered per minute, or per half minute, using different kinds of batteries and
lengths of conducting wire, we may arrive very nearly at the relative powers of the former, and the
proportional resistances offered by the latter.
Another form of voltameter is that in which two tubes are used over each pole, to collect the gases
which may be evolved, separately or singly.
Zinc and Copper Battery.
Fig. 1194. Diagram of the galvanic principle.
Fig. 1195. Isometrical view of a zinc plate and copper case, with a portion of the copper removed.
Fig. 1196. Three sets of plates connected.
Fig. 1197. Portion of a copper case and zinc plate on an enlarged scale, showing the connecting band
and screw.
Fig. 1198. Isometrical view of a battery of ten sets of plates connected.
Fig. 1199. Trough containing the acidulated solution, in which the battery is immersed. h. Orifice
for discharging the solution.
Fig. 1200. Section of three sets of plates, showing a method of connection by leaving a tongue or flap
projecting on one side of the copper case, to be turned up against the adjoining zinc plate, and connected
with it.
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Fig. 1201. Plan of ditto. ccc, show the projecting flaps.
Fig. 1202. Clamp-screw to be used for this method of connection.
Figs. 1195, 1196, 1198, and 1199, are on a scale 2's full size.
Figs. 1197 and 1202
"
"
1/8
a
Figs. 1200 and 1201
«
"
1
«
T6
1196.
1194.
1195.
1204.
c
2
1198.
1197.
r
1200.
c
P
of
06
1206.
1205.
1202.
1199.
1201.
c
1203.
Cast-iron and zinc battery of 10 cells, represented in Figs. 1203, 1204, 1205, and 1206.
Fig. 1203. Plan of trough.
Fig. 1204. Isometrical view of the battery raised above its trough.
Figs. 1203 and 1204 are on a scale 1½ full size.
1211.
1210.
1207.
the
1209.
1208.
RG
/
Z
z
Fig. 1207. Isometrical view of battery of alternate plates of cast-iron and zinc, the trough without
partitions. The battery is shown supported above the trough, by the wood pins pp, which are to be
removed before lowering it. The plates are supported by a piece of board at the bottom, let into the
ends of the frame, similar to the pieces 8 at the sides. The bottom piece is not seen in this view.
54
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ELECTRICITY.
Fig. 1208. Section showing nine of the plates on an enlarged scale, with the method of connection.
The iron plates are shaded and marked ¿¹ is is, &c.; the zinc plates are marked 2' 23 z³, &c.
Fig. 1210. Transverse section through A, Fig. 1203. c c. Circular orifices, t inch diameter, at the
bottom of each partition, at contrary ends, for passing the fluid through the cells.
Fig. 1211. Transverse section through C or D, Fig. 1204.
1217.
1213.
1218.
1214.
1212.
1215.
1216.
1219.
1222.
1220.
1221.
1923.
Fig. 1212. Section through a 5-gallon tin can, holding about 50 pounds of powder, showing it prepared
as a charge for submarine operations. 1. Loading-hole. b. Bursting charge. The priming wires are
shown lashed to the handle and surface of can, so as to relieve the platinum wire within the bursting
charge from all strain.
Fig. 1213. Section through the bursting charge of Fig. 1212, showing the collar C, plug P, and canvas
bag containing the powder.
Figs. 1214 and 1215. Collar and plug for bursting charge, Fig. 1213, showing the neck of plug for
tying round the canvas bag.
Fig. 1216. Plan or end view of plug, showing the ends of the priming wires turned down against the
surface, and the platinum wire lying across them. The spherical hole is left for being filled with fine
powder in contact with the platinum wire.
Fig. 1217. Pointed charge to be used in clearing away mud or soft ground. When forced down to
about three-fourths of its depth, the effect of the explosion will be very great.
Fig. 1218. A mode of lashing two cans together
G
1224.
to form one large charge, if required, with the
method of connecting the two inside priming wires
of each bursting charge, 80 that the platinum wires
of both charges may be included in the same vol-
taic circuit and fired together. This arrangement
has answered well on several occasions.
Fig. 1219. Section of a blast-hole in rock pre-
pared for firing by the voltaic battery. The tamp-
ing is formed by a cone of hard wood, to the bottom
of which is attached the canvas bag holding the
A
powder, and the hole filled up with small broken
B
stone.
Figs. 1220, 1221, and 1222. Section, plan, and
elevation of a bursting charge or cartridge, to be
used for voltaic operations on land, where the quan-
tity of powder to be fired exceeds 200 or 300
pounds.
A
1225.
Fig. 1223. Small cartridge for experiments, and
which may also be used for firing small mines.
The cases of these may either be formed of tin or
pasteboard; if the former, care must be taken to
keep the wires from touching it.
P
1226.
Figs. 1212, 1217, and 1218, are on a scale 3/5 full size.
Figs. 1213 to 1215, and 1219 to 1223, are on a
P
scale 1 full size.
C
Fig. 1216 is on a scale t full size
Fig. 1224. The copper and zinc plates being im-
mersed in water, and their surfaces connected by
the wire w w, it will be found, on placing a gal-
vanoineter G within the circuit, that a voltaic cur-
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rent of considerable intensity is passing through the water from the zinc to the copper, and returning
by the wire. The distance between the copper and zinc plates may be considerable-a mile or
more.
Fig. 1225. Showing the method of firing submarine charges by a single wire, making the sea or other
depth of water complete the circuit. The ends of wire A and B are led to a voltaic battery. Wire A
goes to the negative or zinc pole. Wire B goes to the positive or iron (or copper) pole. pp'. Priming
wires of bursting charge. C. Point of contact of priming wire p', with surface of charge, attached by a
lashing of rope-yarn. The greatest length or depth of water-conductor known to have been used
hitherto for firing charges in submarine operations does not exceed 100 feet, but it is presumed that the
same principle may be extended to much greater depths.
1230.
1227.
1228.
1229.
s
1233.
&
1231.
1235.
1232.
1234.
2
Fig. 1227. Enlarged section of loading-hole. PP. Wood plugs. C. Composition.
Fig. 1228. Longitudinal section through a 72-gallon puncheon, prepared for a submarine explosion by
the voltaic battery, showing the double thickness of head with the loading-hole l through it, and the
lead tube t for the bursting charge. Size of charge about 720 pounds.
Fig. 1229. End view of head, showing the cleat and plug closing loading-hole, the staves 8 lashed
round the surface to guard it from friction, and ballast bags to weight the charge in lowering it to the
bottom.
Fig. 1230. Side view of cask prepared for lowering, showing the slings, staves, &c. The priming
wires are relieved from strain by being secured by the lashing round the cask at X.
Fig. 1231. Section through bursting tube and charge on an enlarged scale, showing the collar, plug,
canvas bag containing the powder, &c. The vacant spaces are filled with composition. The tube may
be made of lead pipe, with a bottom soldered on and the top beaten out to form flanch for screwing to
the cask.
Fig. 1232. Section through collar on an enlarged scale. The circular orifice is left to pass the priming
wires through.
Fig. 1233, side view, and Fig. 1234, plan of bottom of plug, showing the grooves for the wires, with
the ends flattened and connected by the two pieces of platinum wire.
Fig. 1235 shows an arrangement for firing several small charges or blasts on land simultaneously, by
a powerful battery applied at one end of the main wire.
Figs. 1227 and 1221 are on a scale 110 full size.
Figs. 1228, 1229, and 1230
"
t in. = 1 foot.
Figs. 1232, 1233, and 1234
"
1 full size.
Fig. 1236. Isometrical view of a mercurial apparatus or igniter for forming the simultaneous ignition
of several mines. The upright A is hinged to the inside of the frame, and on being unhooked falls down
upon the front piece containing the six cups C filled with mercury. The pieces of wire, let through the
arm B, numbered from 1 to 6, enter the similarly numbered cups at the same instant, the connections
being completed by the wires 1' 2' 3ª, &c., which enter the bottom of the cups, and are turned up against
the front part of the frame. The two extreme batteries, 1 and 6, are here only shown connected with
their conducting wires and the apparatus. The intermediate batteries would be conducted in the same
manner, but are not shown, to avoid confusion.
Fig. 1237. Section through front of frame, and mercury cup on an enlarged scale, showing the arm
down upon the frame, with the connection complete.
Fig. 1238. Isometrical view of cylinder battery connected.
Fig. 1239. Battery in plan.
Fig. 1240. Box in plan.
Fig. 1241. Section through A BCD, Fig. 1239. c c. Copper cylinder. 88. Sulphuric acid, water, and
sulphate of copper. z 2. Zinc rods, within ox-gullets, containing dilute sulphuric acid only.
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ELECTRICITY.
1236.
1237.
A
1239.
1238.
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B
1941.
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1242.
1244.
X
B
C
A
T
s
1243.
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C
A
P
P
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ELECTRICITY.
429
Figs. 1242 and 1243. Galvanometer. C. Single cell of a Daniell's battery. Copper cylinder 21
inches diameter, and 2f inches high. Z. Zinc rod, } inch diameter. D. Rectangular coil of insulated
wire, one-sixteenth of an inch diameter, surrounding the needle in a vertical direction. One end of the
wire is connected to the cylinder at X; the other end forms the positive pole of the galvanometer. In
testing the completeness of an electric circuit, the two ends of the wire forming that circuit must be
brought in contact with the poles P' of the galvanometer, when the needle will be instantly deflected
if the circuit is perfect.
Fig. 1244. Voltameter. A. Glass vessel closed at top, containing acidulated water. T. Graduated
glass tube entering the liquid in the vessel. pp. Platinum wires, hermetically sealed into the tube.
&. Stopper for closing the second orifice, while the vessel is inverted for filling the tube.
Fig. 1242 is on a scale } in. If 1 foot.
Fig. 1243
"
1
full
size.
Fig. 1244
"
«
"
The following is from the report of Alexander Parris, C. E., conducting the works at the Navy Yard,
Portsmouth, N. H., dated November 9th, 1840. This report was addressed to Col. S. Thayer, Boston.
"Our operations during the past season were confined chiefly to the construction of quay walls and
the foundations of two launching ways, the whole of which are built of stone. The character of the
bottom of the river where the work was laid, rendered blasting or other means necessary, before a pro-
per surface for the foundation could be obtained it was desirable to give it a slight inclination inward,
so that the face of each course of stone should lie somewhat higher than the inside, thus preserving a
proper bottom for the walls and rendering them perfectly secure. This bottom is a hard slate-rock, and,
with the exception of some level portions, extremely uneven, with slopes of almost every grade, gener-
ally in an outward direction from the shore. The depth of water in the line of the walls varies from
fifteen to twenty feet at low water, and from twenty-five to thirty below the high tides. The depth of
water added to a strong and variable current, caused me to anticipate much difficulty and great expense
in all operations below its surface.
'But we were fortunately provided with a fine diving-apparatus, consisting of a cast-iron diving-bell
and a powerful air-pump attached. This apparatus was worked from a vessel of strong construction
and light draught, fitted expressly for the purpose. A system of signals and messengers was established
for communication between the workmen in the bell and those on board the vessel; by these means,
every want was speedily made known and answered. Four workmen, divided in two gangs, were em-
ployed for working in the bell, which made four descents per day, occupying at each time two and a
half hours, the two gangs alternately relieving each other. The bell was amply supplied with a con-
stant stream of fresh air, and but two or three inches of water remained in at its greatest depth, so that
the men worked in a comfortable state, perfectly dry, and with no more difficulty of respiration than on
dry land.
In deciding upon the best means for preparing the bottom for the reception of the foundation of the
walls, I was greatly at a loss which to adopt. It appeared to me that in adopting the method prac-
tised by other engineers, great expense and difficulty would be incurred; and as it did not appear that
their method had been employed in blasting the solid rock at the bottom of a river, in any of their ex-
periments, I was somewhat apprehensive of their utility for operations of this kind, and whether the
cost would justify the trial. In order to satisfy myself with regard to the expense of an experiment
with the galvanic battery, I applied to Mr. Daniel Davis, jr., philosophical instrument maker of Bos-
ton, for the necessary information, when I was convinced that a very trifling expense would procure
such a trial as would satisfactorily decide the merits of the apparatus. Mr. Davis kindly assisted me in
making the experiments, which were tried at the Navy Yard, at Charlestown, and I had the pleasure of
witnessing the most satisfactory results, and without hesitation determined to apply the means to the
work in hand.
"The galvanic battery, which was constructed by Mr. Davis, was one of Doctor Hare's invention, of
Philadelphia. It consists of two vessels or jars, each formed by two concentric cylinders of copper, ad-
mitting of a cylinder of zinc between. Two copper wires, termed the conducting wires, formed the
medium by which the electrical fluid was communicated to the charge from the battery. These wires
were closely wound with thread in order to prevent their coming in contact with each other, and both
covered tightly with tape, and afterwards served round with twine, thus forming a single coil. At each
extremity of the coil, the wires were separated for a few inches like a fork. This form of the galvanic
battery, termed by Doctor Hare the 'Calorimeter,' is the most simple and portable of any that I have
seen its power for blasting gunpowder may be increased to any required degree; either by enlarging
the size of the jars or increasing their number. We had in addition to this apparatus, a simple con-
trivance for proving the charges of powder, which is termed the Electrometer.'
"The charges used in blasting consisted of various quantities of gunpowder, according to the effect
required, from four ounces to a pound. They were enclosed in perfectly air-tight tin canisters, the
smallest being an inch and a quarter in diameter, and the diameter of the largest about two inches
the lengths of the canisters were eight or nine inches. Two copper wires were introduced into the
canister about half way down, with the extremities connected by a fine platinum wire; the other ends
of the wires projected twenty or twenty-five inches beyond the mouth of the canister, which after being
filled with powder, was closed and effectually secured with a water-proof composition. It will be ob-
served in thus preparing the charges that the whole is completely air and water tight, and that no vent
to the powder remains, an advantage of which I shall further speak.
"The operation of blasting is carried on in the following manner: The hole in the rock for the recep-
tion of the charge, is drilled to a proper depth by the workmen in the bell; the canister is then inserted
with the ends of the copper wires extended outside of the hole, which is then filled up or tamped with
coarse sand. The ends of the conducting wires are then connected by means of clamps to the wires
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ELECTRICITY.
leading from the charge; the other end of the coil is then led up, as the bell is hoisted to the surface, to
the battery, which in all our experiments was placed on a floating stage directly over the charge. The
jars forming the battery are brought near each other, and their whole power concentrated by connecting
them together with a short copper wire the end of one of the conducting wires is then brought in con-
tact with one pole of the battery, and the end of the remaining wire similarly disposed with the other
pole, when the explosion instantly follows by the platinum wire in the charge becoming intensely
heated as the electrical current passes through the conducting wires.
" We made during the past season nine blasts, with but one failure, which was caused by the platinum
wire in the charge becoming accidentally broken, so as to render the electrical circle incomplete this
probably occurred in tamping, an operation which must be conducted with care, as this accident is most
liable to be incurred, of all others, owing to the extreme delicacy of the wire. The object of the elec-
trometer is to detect whether this has taken place before the charge is inserted in the rock, and may
always be ascertained by a simple trial.
It must be obvious to every one, at all experienced in blasting rocks, that this method has advan-
tages in many respects over the old methods, both under and out of water. The danger of accidental
I explosion is entirely prevented; these occur for the most part in the old practice by carelessness, while
in this, great care and nicety are required to produce the explosion. There is very little time required
in charging, as the canister is simply inserted in the hole and tamped with sand; the whole time occu-
pied in this operation, and making the connection with the conducting wires, in the present cases rarely
exceeded twenty minutes. There is great expense and trouble saved in the absence of the train or
fuse, which was indispensable in the old methods, especially under water, where was always required
a water-tight hose or tube leading to the surface, which was always destroyed by the explosion. Here
nothing is lost or injured except the canister containing the charge. The explosion of the charge is re-
duced almost to certainty, and should cases of failure occur, it can be approached with safety, without
the suspicion that fire may be near it. The most important advantage in an economical view, is that
the effect of the charges is much greater than in the old way, in consequence of there being no vent-
hole; the whole explosive force of the powder is thus gained, while by the old methods much of it 18
lost. Our smallest charges displaced a much greater quantity of rock than the same amount of powder
by the old means, which we had opportunities of experiencing. With these advantages, this method of
blasting places in our hands the most ample means of clearing harbors and rivers, of rocks, &c., in any
reasonable depth of water.
" In using Dr. Hare's apparatus, it appeared that an important advantage was gained over that of
Daniell's, employed by some operators, inasmuch as a very troublesome arrangement, indispensable in
the latter, was avoided. This consisted in not being obliged to insulate the conducting wires from the
water, as in such a case the connection of the conducting wires with the charge must be made before
the canisters are placed in the rock; every portion then of the wires, where the connection is made, must be
covered with the water-proof composition. By Daniell's apparatus, it appeared that water was a con-
ductor, thus destroying the electrical circle, if any part of the conducting wires came in contact with it."
Electricity applied as a moving power.-The operation of voltaic electricity in magnetizing iron, and
the disappearance of the excited magnetism directly its action is suspended, or nearly so, has furnished
a means of obtaining to a certain extent a considerable moving force applicable to the purposes of ma-
chinery and although in all the attempts hitherto made, engines of great practical value have not been
obtained, yet very considerable advances have been made and are still making in electrical machines.
The general principles resorted to in the construction of electro-magnetic engines are these,-either a
rapid change of polarity in masses of iron surrounded by spiral coils, 80 as to cause them to alternately
attract and repel other electro-magnets brought within their influence, or otherwise a rapid magnetizing
and demagnetizing of masses of iron in a similar way, without any change of polarity by which an
attractive force is brought to act upon other masses of iron, so long as the attraction is operative in pull-
ing them onward, and no longer. In both these cases a rotary motion is obtained by fixing the at-
tracted masses on the circumference of a wheel, and placing the wheel so as to admit of the operation
of the electro-magnets upon the extremities of its radii, as in any other similar case of the application
of a moving force to the circumference.
Mr. Cook, of Saratoga, made an interesting exhibition of an electro-magnetic machine, in the year
1838, in Barclay-street, New York. The whole apparatus was of the most simple construction, con-
sisting of two sets of magnets, one revolving within the other. The external magnets being excited by
the fluid generated by the action of an ordinary galvanic battery, while the polarity of each inagnet was
constantly and regularly changing, a perfectly uniform motion was communicated to the cylinder, which
might be increased indefinitely as additional force is applied. The machine was thirty inches in diame-
ter, and contained seventy-eight magnets, each weighing four pounds. The machine, in full operation,
made eighty revolutions per minute-considerably more than can be obtained by the force of one man.
Mr. Cook states that the power of the machine may be greatly increased by adding to the number of
magnets, without enlarging the battery.
Professor Jacobi, of St. Petersburg, by means of an engine on this principle, succeeded, in the years
1838 and 1839, in propelling a boat upon the Neva at the rate of 4 miles an hour. This boat was 28
feet in length, about 7 feet wide, and drew nearly 3 feet water. It contained ten persons; the engine
was worked by a voltaic battery of sixty-four pairs of platinum plates, excited with nitric and sulphuric
açid, and propelled the vessel through the medium of paddle-wheels.
In 1842, Mr. Davidson constructed an electro-magnetic locomotive engine, which was tried on the
Edinburgh and Glasgow railway, the carriage of which was 16 feet in length and 6 feet wide, weighing
above five tons, including batteries and magnets. It was propelled at the rate of about 4 miles an hour.
A new suggestion in the application of Electricity as a moving power will be found under the head
of ELECTRO-MOTIVE ENGINE: but as yet the only practical machines, that we know of, driven by elec-
tricity, are the electric clocks used on many of the European railways.
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ELECTRIC LIGHT.
481
Amongst other applications of electricity to useful purposes, the application of magneto-electrical
action in arresting the oscillations of the compass-card on board ship is not the least important. Elec-
trical currents are excited in non-magnetic metals, such as copper, zinc, &c., when placed near a magnet
in motion, or when themselves set in motion near a magnet; and these currents 80 tend to arrest the
motion, that if an ordinary magnetic needle be caused to oscillate within a ring of copper, the amplitude
of the oscillations rapidly diminishes, and the needle is speedily reduced to rest. On this principle, the
common compass-card employed at sea is placed within a dense ring of copper,-the poles or extremi-
ties of the magnet being near the interior of the ring; this, with some valuable and judicious improve-
ments in the construction and mounting of the needle, so fetters the vibrations, that even although the
instrument be extremely sensible of the least motion, and of the action of the magnetic force of the earth,
yet the compass-card is found steady in the heaviest sea, and under the violent motion of steamboats
when struggling with a gale.
For further and still more important applications of electricity to the improvement of the arts, and
the conveniences of life, see Electro-Metallurgy, Electro-Magnetic Ore Separator, and Telegraph
ELECTRIC LIGHT. The improvements in the construction of galvanic batteries consist in making
them on what is termed the "perfluent" system of supply and discharge, to contradistinguish it from the
64 percolating" system, which has recently come into extensive use. According to the percolating
system, the liquid employed (usually sulphuric acid) is supplied to and discharged from each of the
cells of the battery, in separate and distinct streams or series of drops; the liquid, as it becomes
exhausted, though not entirely so, dropping out through an oritice in the bottom of the cell, and being
then allowed to run to waste, and the place of the discharged liquid being supplied by fresh drops
descending from above into each cell. But, according to the new system, the liquid is supplied in one
stream only, which passes continuously through the entire series of cells, entering by the first cell of the
series, and passing off through the last. No diminution of electric intensity is observed to take place in
the perfluent battery, from bringing the cells into communication with one another, owing to the
circuitous course which the fluid is made to take between cell and cell. In proportion, of course, as the
duration of the transit through each cell is shortened, the chance must be proportionally lessened of
each portion of the liquid coming into contact with the acting metal or element in that cell; yet, as no
drop of the fresh liquid supplied to the battery can make its way to the final discharge outlet without
going through the whole of the cells, what it misses in the first cell, it is sure to encounter in one or
other of the remaining cells. The cells last in order of a perfluent battery necessarily act less power-
fully than the earlier cells of the series; as, for example, the last six cells of a series as compared with
the first six. The diminution of power, that is to say, the quantity of electricity which the cells are
capable of circulating, does not appear, however, to follow exactly in the ratio of the strength of the
exciting liquids; for the difference in power between the middle and initial cells of a series is propor-
tionally not so great as the difference between the middle and the terminal cells. When it is desirable
to obtain intensity in the electric current rather than great quantity, the terminal cells should be made
about equal to the quantitative power of the others, by uniting the similar conducting wires of several
cells together, and using them as if proceeding from one cell. Thus, as it would be technically expressed,
the last three cells in a fifteen-cell battery (say the 15th, 14th, and 13th) might be connected for quantity,
and the two next preceding pairs (say the 12th and 11th, and 10th and 9th) be connected also for
quantity, and the first eight cells might be worked singly, in the usual manner of a series. But, how-
ever great may be the differences in power between the initial, middle, and terminal cells of a series in
each cell, regarded by itself apart from the others, the degree of exhaustion, and consequently of electric
action, is always very nearly uniform throughout every part of the cell.
The details of a battery constructed on this perfluent principle are represented in Figs. 1245, 1246,
1247, and 1248 of the drawings annexed. Fig. 1245 is a view of the battery, as seen from above; Fig.
1246 is a vertical longitudinal section; Fig. 1247 is a view of the trough from beneath; and Fig. 1248
is a vertical cross-section. A is a wooden trough, the parts of which are firmly bolted together; a a are
slate partitions, the edges of which fit closely into the sides and bottom of the trough, and are about
two and a half inches apart; bb are thicker partitions of wood, which are inserted at short intervals, say
every six cells, and made fast to the sides by screws and nuts ; c¹ are two parallel rows of holes made
in the bottoms of the cells, two in each; dd' are two corresponding rows of wooden covers, which are
made fast to the bottom of the trough, Fig. 1247, one underneath each adjoining pair of holes,
as c c or c' c¹, with the exception of the two end ones, which cover one cell only; e is a groove cut out
in the upper surface of each cover, and made just of width enough to embrace two of the cell holes,
as cc or c1 c¹, and 80 establish a channel of communication between them; f is an aperture made in the
bottom of the end cover of the series of holes; d and f', similar apertures in the bottom of the opposite
end of the same series of holes, into each of which apertures there is inserted a piece of copper tubing,
to which there is attached one end of a flexible hose, g or g¹, (made of vulcanized caoutchouc, gutta
percha, or any other suitable substance or combination of substances,) which terminates at the other end
in a funnel h or h¹; and i i' are eye-bolts affixed to the ends of the trough on the outside, which
respectively sustain in an upright position the funnels h and h¹, there being a slit or opening in the eye
of such bolt, to admit the neck of the funnel. The whole of the inside of the trough is well coated with
marine glue.
The mode of operation with this apparatus is as follows: The liquid is poured in at the funnel h, and
passes into the first cell through the hole o of that cell; from the first cell it goes out through the hole B
into the first of the grooved covers of the series d, whence it flows into the second cell through the
hole c' of that cell; from the second cell it next passes through the hole c of that cell into the second of
the grooved covers of the series d; and 80 on to the end of the series, (as indicated by the arrows in
Fig. 1245,) when it discharges itself through the flexible hose g' and h' into a receiving vessel K.
The arrangement just described is, however, chiefly suitable for those batteries which use but one sort
of exciting liquid, but in batteries where two fluids are used it may be expedient to adopt the modifi-
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ELECTRIC LIGHT.
cation of the perfluent system represented in Figs. 1249 to 1254. The internal cells in this case are
supposed to be made of earthenware or some other porous material. Fig. 1249 is A side view of one of
these cells, and Fig. 1250 a vertical section across the middle. A hole Q is made in the bottom of this
cell, and into this hole a varnished copper tube r, with a collar and washer of vulcanized caoutchouc at
top, is dropped. The tube is pulled tightly down upon the washer, in order to prevent any of the liquid
escaping between the washer and the bottom of the cell. Or, instead of this arrangement, one of the
description represented in Figs. 1251 and 1252 may he substituted. S is a cradle which is cemented on
1259.
N
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1261.
3
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to the under end of the cell by marine glue, and encloses it completely. The tube r is screwed on to
the bottom of this cradle, and through it up to the hole in the cell. In both cases the tube has an oval
aperture w cut transversely through it, and terminates at its under end in a solid screw-point. The
trough for the reception of porous cells of this description is made in the manner represented in Figs.
1253 and 1254; the former being a transverse vertical section of the trough through the centre of one of
the cells, and the latter a longitudinal vertical section. Q is the internal porous cell, and Y the zinc plate
suspended therein. X X are the plates of negative surface, say copper, placed outside of the porous
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ELECTRIC LIGHT.
433
cell. ZZZ are the sides and bottom of the trough, the spaces m m between which and the porous cell
form the external cell, which contains the second fluid, (say sulphate of copper.) A is an open channel
for the discharge of the second fluid, which runs along the outside of one wall of the trough, near to the
top, and communicates by lateral apertures pp in the wall, with the spaces inside m m, appropriated to
that fluid. V is a grooved or channelled under-cover, which extends along the bottom of the trough
from end to end, and comes immediately under the line of holes in the porous cells Q. The lower end
of the tube r, which is attached as aforesaid to the bottom of each porous cell, and enclosed by the
cradle, is passed downwards through an orifice in the bottom of the trough, and also through another
orifice in the bottom of the under-cover V, till the oval aperture w in the tube coincides with the groove l
in the bottom of V; so that when the whole of the cells are fixed in their places, the channel t forms
through the medium of the apertures w w a common channel of communication between all the cells.
U is a nut which takes on to the end of the solid screw-point of the tube r, and by turning which
the parts S, r, V, and Z are all screwed tightly together. For the sake of greater security against
leakage, and against the intermixture of one of the fluids with the other, washers of vulcanized
caoutchouc are inserted between the crade S and the bottom of the trough, and between the bottom of
the grooved channel V and the shoulder of the nut U. E is a second under-cover which runs parallel
to V, (on one or either side of it;) the groove e, in which the second cover communicates by a series of
holes n n with the external cells above, containing the second fluid, serves as a common channel through
which these cells may be supplied from a flexible hose. The second fluid is, after passing through the
external cells, discharged from the end of the channel A.
The perfluent system may be also carried into effect by employing siphons instead of the grooved
under-covers dd', V, and E, before described, to transmit the liquid from cell to cell successively, as
shown in Fig. 1255, which represents two adjacent cells of a battery. The long end A of the siphon
descends to near the bottom of one cell, in order that it may carry over the densest portion of the liquid
therein, and deliver it through the short end B into the next cell. Or, if the liquid employed is of such a
nature that it becomes lighter as it becomes exhausted, (sulphate of copper, for instance,) then the legs
of the siphon are reversed, the liquid entering it by the short end, and being carried over by the
long end.
Part of the invention consists in attaching to all galvanic batteries in which a gradual change of liquid
is required, an equilibrated hydraulic cistern and graduated meter, such as represented in Figs. 1256 and
1257. A is a cask, closed at top, so as to prevent the action of the atmospheric pressure on the surface
of the liquid contained in it; and b is an orifice near to the bottom, which opens into a small outer
cistern c. This arrangement ensures that the liquid flowing through any channel from the little cistern c
will always flow at the same rate, whether the cistern be full or nearly empty. From this little cistern
a loose piece of vulcanized caoutchouc tubing d proceeds, and is connected with the glass tube e, from
which is suspended the meter f, having a small hole at the bottom, 80 that the rate of flow out of this
hole is indicated by the height at which the surface of the liquid stands. The meter is graduated to
units, which shows the amount of flow requisite to supply the chemical action which is going on in the
battery when the electric current is circulating at a rate indicated by corresponding units on the galvan-
ometer described in Fig. 1258, which is included in the circuit. The meter, with its tube d, is suspended
so as to enable the rate of flow to be adjusted by hanging it at an altered level in relation to the cistern,
according as the galvanometer may indicate to be necessary. The parts d e form in fact a siphon, which
only requires to be filled with liquid when the apparatus is first set in action, after the cistern is
charged. The liquid issuing from the meter is received by a funnel h, or otherwise led to the battery.
Also the employment in galvanic batteries, having copper or mercury for the negative element, of a
liquid amalgam of zinc and mercury, enclosed in a bag or case of lawn or horse-hair cloth, or any other
finely reticulated fabric, but not made of metal, which allows of the acid passing freely through its
meshes to act on the bottom and sides of the zinc amalgam, while the bag or case retains the amalgam
itself.
Again, the employment of lead as the positive element in galvanic batteries, (instead of the zinc
which is now commonly used,) combined with a solution of nitric acid or of acetic acid, in some one or
other of the forms best calculated to act on the lead.
The new galvanometer is such that it can be made a permanent adjunct to, or part of the battery, 80
as to be always indicating what amount of electricity is circulating when any sort of duty is being
performed by it, and the weights of materials combining or used per minute at any particular time.
This improved galvanometer consists of a thick piece of insulated copper wire A wound round a wooden
or brass cylindrical centre, fitted with ends C C. One end of this coil is in metallic connection with the
positive or negative pole of the battery, and the other extremity is placed in connection with the part of
the lamp, (or other piece of mechanism for actuating which the battery is used,) which would receive
the conductor from the said pole of the battery. In the hollow cylindrical centre of the coil there is
placed a rod of soft iron d, as shown in the figure, which moves loosely up and down in it, and is pro-
longed by a short brass stem or index e. A graduated scale f is fixed to, and rises from, the upper end
of the coil, 80 as to show the height at which the electric influence causes the index to stand. The
graduations are represented in the figure as marked on a glass tube, within which the index and rod d
slide. These graduations are 80 made as to indicate the number of grains of pure zinc consumed per
minute in each cell of the galvanic series, the current produced by which causes the index to stand at
each such division of the scale. Any galvanometer of this kind can be graduated from a standard one.
The standard can be graduated by ascertaining experimentally the weight of zinc consumed per minute,
but a less tedious process is to graduate it from a Petrie's Galvanometer, which indicates all the required
units of electricity and their fractions, by means of weights; the accuracy of that instrument being first
tested by one such direct experiment on the zinc consumed. This improved galvanometer may be made
of a shorter and thicker wire, making fewer coils, if the iron rod is partially counterpoised by a spring
or weights, or hydrostatically with mercury.
55
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434
ELECTRIC LIGHT.
Figs. 1259 and 1260 are representations of a lamp embodying this improvement. The skeleton of
this lamp is composed of a foundation-plate of wood A, a sole-plate B of brass, firmly connected by
pillars C and a three-legged stand K rising vertically from the sole-plate B, the feet of which are
fastened to B by nuts beneath, but insulated by circular washers of dry hard wood (of the form shown
in section i.) A hole is bored vertically down through the centre of the
top of the stand K, into which hole the upper electrode N is fixed by three
1260.
metal wedges jambed into key-ways or channels, sloping upwards and
outwards, so as to keep the inner faces of the wedges parallel to the
central axis. A glass shade is fixed to the sole-plate B 80 as to cover K.
H G is a shaft which slides vertically into the central axis of the lamp,
through holes in A and B, and has a socket at top which carries the lower
electrode M. The lower part G is cut with teeth which work into a
pinion F, which turns on a spindle in fixed supports. A barrel F' is
attached to the pinion F. and a weight W is suspended by a string which
passes round F' and is fixed to it, 80 as to counterpoise the weight of HG.
On the spindle of the pinion F is fixed a wheel E, having square teeth. A
lever T turns loosely on the same spindle as a fulcrum, and carries a
double pawl U V, which turns on a pin which projects from the side of T,
so that this pawl U V can lock into the teeth of the wheel E in either
direction. A long horizontal lever Q passes over this pawl from a joint or fulcrum a, and this lever
carries a light spring or tongue l close beneath it, the end of which is kept from springing away from
the lever by resting in a step in a little stirrup or fork d, which is attached to the lever Q. and embraces
the wheel E and the end V of the pawl. The pawl and its lever T are kept in a state of slow vibration
from side to side by means of a crank S, which works in a fork at the end of T, the crank S being made
to revolve by an ordinary train of wheel-work, furnished with an escapement or fly-wheel A', and driven
by spring power or weights. When the lever Q is turned a little downwards its tongue I presses V into
the teeth of the wheel E, and the vibratory motion of T causes V to drive the wheel round, notch by
notch. The wheel does not follow the pawl in its back motion at every stroke, for this is better ensured
by having a spring n (Fig. 1260) fixed to A, and pressing against the side of G. This motion of the
wheel causes the pinion to elevate the rack G slowly, 80 as to raise its electrode M towards N. But
when the lever Q is raised or turned upwards, the notch in the stirrup lifts the tongue l off V, and
allows U, the heaviest end of the pawl, to drop into the teeth of the wheel E. This drives it round in a
contrary direction, so as to lower the rack G and draw its electrode M further from N. Whenever the
lever Q is raised, the lower step in the stirrup d catches the sides of V and draws it (V) up out of the teeth
of the wheel, in case v should have become jambed or hitched in the teeth, 80 that the counter-weight
of U might be unable to release it. The means by which the end of the lever Q is raised or lowered
are these: R is a regulator coil, one end of its wire is connected with the binding-screw e, and the other
end, L, is brought up and fixed in contact with K. An iron rod 0 moves freely up and down in the
central hole of the coil, and is prolonged upwards by a stem of wood p, by which it hangs to the end of
the lever Q in the manner shown in Figs. 1259 and 1260. The rod o passes through a hole in the
centre of a cup y, which screws into the bottom of the coil-case. Around o there is a circular weight X
which rests on a small step in 0. when o is raised. When o sinks below its medium position it is left
behind, resting on the edge or rim of y. The object of this arrangement is, that when o is actuated by
a force equal to its own weight, added to half the weight of X, then it will have a tendency to return to
its medium position, with a force of half the weight of X, whether it be raised higher or sunk lower than
that position. The mode of action is as follows: The end of the negative wire from the battery is set
in the binding-screw f, and is conducted thence by a metal connection to the supports of the spindle of
the pinion, and to the spring n. The current passes through these into the rack; thence to the lower
electrode M, from which it passes to the upper one, N, producing the light between them. From N it
proceeds through the stand K to the wire L, of the regulator; thence to the clamp e, which is in con-
nection with the other end of the regulator wire, and into which the positive wire from the battery is
clamped to complete the electric circuit. The current, in passing through the regulator, tends to raise
the iron centre o, which being connected to the lever Q, is counterpoised by the weight W¹, which
screws along an extension of the lever beyond the fulcrum a. To put the lamp into adjustment, the
driving geer being wound up, and the battery being in a state of activity fit for the permanent action
intended to produce the light, and its wires connected with e and f, as described, the lever Q is raised
by hand until the electrodes have separated to the greatest extent compatible with obtaining a perma-
nent light from them. The screwed weight W' is turned backwards or forwards until it keeps o
balanced, just so as not to sink below its medium position, when the electrodes are separated as afore-
said. When in this position, the shoulder of o touches the weight X, which is resting on the rim of y.
The lever Q carries a little projecting piece or catch g, which meets the bent arms attached to the crank-
spindle S, and thus arrests the motion of the crank, when the lever lies so that o is in its medium
position; but whenever it rises above or sinks below that point, the catch g allows h h to pass beneath
or over it accordingly, 80 that the crank can revolve freely and work the ratchet U V.
A front view of a lamp on this plan is given in Fig. 1261, and a side or edge view in Fig. 1262. A'
is the disk, which, as shown in section, Fig. 1262, resembles in its form two cones, placed base to base,
so that there is always one sharp or feather-edge in sight of the negative electrode, which is of the
ordinary single-cone form. B' is the scraper; B2 is a frame which carries the shaft C², to which the
disk electrode A' is attached. Dª and E2 are a bevelled wheel and pinion, which geer into one another,
the latter being fixed to the shaft G2. At the bottom of this shaft there is another wheel H2, to which
the clock-work or other apparatus for giving motion is attached. The shaft G' may be insulated in
various ways, either by the interposition of plates of ivory or wood, J K, screwed together, or by gutta-
percha or india-rubber rings.
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ELECTRIC LIGHT.
435
To increase the temperature of the metallic electrode A¹, the operator sometimes passes the metallic
holders BB through a block of glass DDD, or some other similar bad conductor of heat, as repre-
sented in Fig. 1263, so that the heat and radiant light may be developed with as little loss of the former
as possible by radiation.
An elevation of a small iridium bracket lamp is given in Figs. 1264 and 1265. A' is the electrode
of iridium, which is fused on or otherwise fixed to two pieces of platinum B B, which are fixed into two
copper or other metallic holders C C. These holders are insulated by means of ivory, wood, or vul-
canized india-rubber washers DD, or some other suitable non-conducting substances, 80 as to prevent
contact with the bottom metal plate of the lamp E. To one of the metallic holders a copper wire a¹,
passing through the hollow tube B', is connected with one pole of the battery, and the electric circuit is
completed, and the current made to pass through the brass-work of the lamp to the electrode, by turn-
ing the ivory knob X, which is attached to a screw-shank Z, making a metallic communication with the
other holder. W Y is a ring of brass, which is screwed into the bottom of the lamp. A glass shade,
of any shape or form, may be placed on the plate E.
Fig. 1266 represents a triple electrode suspending-lamp. A A A are three ivory knobs, with metallic
shanks, for making the necessary communication, as before described.
An apparatus embodying the chief of these arrangements is represented in Fig. 1267. The parts in
this apparatus which are similar to those in the permanent light apparatus, Figs. 1259 and 1260, before
described, are indicated by similar letters. A helix coil of insulated copper wire A, is employed for the
purpose of producing the prime-moving force which actuates the sliding shaft which holds the electrode.
This helix is fixed to the bottom of the framework CC'C". A cylinder of soft iron, B, moves freely up
and down in it; to the top of B is fixed the rack E, which slides through the hole at c", and carries the
electrode M, fixed in a socket, 80 that this shaft can move the electrode M to or from the lower end of
the electrode N, which is fixed in the top of the tripod K by wedges or screws. K is fixed and fur-
1267.
1266.
1270.
1271.
K
1269.
b
1268.
a
b
R
1265.
B
1264.
d.
1263.
D
D
B
B
nished in the same manner as that shown in Fig. 1259, and before described. The weight of the shaft
BE is rather overbalanced by the weight Q, which is attached by a string passing over a pulley R to B.
A pinion F works into the rack E, and fits it loosely with a back lash of about a tenth of an inch. The
pinion F is connected with an ordinary train of multiplying wheel-work (concealed behind the brass
plate c"") and terminating by any well-known sort of fly or escapement motion of such kind, that FY
will be prevented from revolving quickly, but will at the same time yield with a slow motion to any
slight force from the rack E. 80 as to prevent the rack E from moving up or down too quickly. The
negative wire from the galvanic battery is connected with one end of the helix coil A, and the other end
of it is soldered to the brass case, 80 that the current passes through the helix wire to its case, and
thence by means of the springs D which are fixed to the case, and are in contact with the iron cylinder
B, up the shaft DE, to the electrode M, whence it flows through N, down K, and returns to the positive
pole of the battery, by means of the wire y. But when the current thus passes the helix, A causes the
shaft B to be drawn downwards, which motion separates the two electrodes MN, and light is evolved
until the electrodes become too far separated, when the current suddenly ceases, the light becomes ex-
tinguished, and the helix ceases to draw B downwards, when the weight Q begins to draw it upwards
again, until the electrodes touch one another, whereby the electric current is re-established, and the light
is repeated as before.
The apparatus which has been described, Fig. 1267, may be modified in manner following: Fix a
regulating coil with a properly weighted iron centre, &c., just like that described in Fig. 1259, (at R, o,
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436
ELECTRIC LIGHT.
?, x, y.) This coil is fixed to c, Fig. 1267, and its wire is permanently included in the electric current
and 0, instead of P, moving a ratchet VV; when it drops, it presses a spring or lever in connection
with the negative wire from the battery in contact with the shaft B, so that most of the electric current
passes from the negative wire through the lever to B direct, and B is no longer drawn down by the
action of A, but begins to rise by the force of the weight Q, which in this modification of the apparatus
is made to overbalance the shaft as it does in Fig. 1267.
The apparatus employed, Fig. 1267, in any of the preceding modifications may be made to act by
substituting the arrangement shown in Fig. 1268, for the parts A and B, which gives a greater moving
power, and allows the electrode shaft to move through a long space not limited by the length of the
coil A. A', Fig. 1268, is a helix coil, similar in construction to A, but differing in form, as is indicated
in the sectional view, Fig. 1268. A short hollow cylinder B' is substituted for B; a brass rod B" (or a
bar feather edged," for the sake of lightness) passes freely through B', and ratchet teeth are cut in it
as shown, by which a spring ratchet g suspends B', in the position shown in the engraving. An end H,
which screws on to the top of the central tube of the coil A, carries the conducting springs D D, and
guides the shaft B"; when the shaft B" rises (carrying B' with it) it brings the projecting end of the
ratchet g against the slanting side of H, the pressure of which pushes the ratchet out of the teeth and
lets B' descend for the space of one notch or tooth, 80 that B' is always ready when the current in A'
acts to draw the shaft B' a fraction of an inch lower, and yet does not prevent the shaft from gradually
moving upwards to any extent to supply the waste of the electrode, while B' never follows the shaft
higher than H.
The helix coil last described, Fig. 1268, may have its action on B' augmented by making certain
parts of the case in which the coil is wound, to be of soft iron in place of brass, as shown by the section
of the case in Fig. 1269, the parts marked a being iron, and those b brass.
An electro-magnet may be used in place of the helix coil surrounding the moving piece of iron B';
the poles of the electro-magnet being presented obliquely or directly beneath B¹, the form being altered
so as to be the better suited to be attracted by both poles of the electro-magnet.
Reflectors may be adapted to electric lighthouse lamps as well as to electric lamps of all surts.
The intensity of the electric current (whatever may be the nature of the lamp or apparatus used for
producing the light) is effected by including in the electric circuit a long coil of insulated copper ribbon
wound in an iron case, as shown in section, Fig. 1270, and part side view with cover removed at Fig.
1271. The coil may be made in pieces separately wound on, and their ends joined in succession, the
two extreme ends A e of the first and last coils being made to pass through the holes Pq in the case.
A hollow cylinder of iron, or a number of bits of flat iron bar gh, are placed around the coil like the
staves of a cask, and are held together by elastic bands of vulcanized caoutchouc. A good proportion
for the substance of the coil is one-hundredth of a square inch of copper in section to every 40 yards ot
length. The ends of each coil are held from slipping back or unwinding, while the next coil is being
wound, by being bent round and backwards over a pin K K'. screwed into the side of the iron case.
The numbers annexed to the arrows indicate the succession of the different portions of the coil on which
they are placed. The letters ABCDE indicate the commencement of each of the coils, and a bcde
their several terminations.
The solid electrodes employed in electric lamps in supporting tubes, are represented in Figs. 1272,
1273, and 1274. A tube e, serves to guard the electrodes, to hold them steady, and to conduct the
electricity freely up to the top part of the electrode,
the current being passed into the tube through the sole-
1272.
plate c", which is put in metallic connection with the
negative wire. D"D" (Figa. 1272, 1273, and 1274) are
spring conductors (they may be of iron) fixed on the
1274.
1273.
#
tube e, the tips of which embrace the electrode near the
point where the light is developed. The electricity has
by this means a free passage from the tube into the
electrode. The tube may be fixed mechanically to the
B
framework c c", and yet insulated electrically from it,
as shown in Fig. 1273, by means of collars of dry hard
wood 22, on the same principle as the legs of the up-
c
per electrode-stand K, are insulated from the sole-
plate c".
The electrode may be composed of many pieces
slightly joined together, end to end, and placed in a
tube, Fig. 1274, of any required length. To obviate
the necessity of joining the parts firmly, the following
arrangement, Fig. 1274, has been contrived, wherein
the electrodes need never be drawn backwards in the
tube: c" is a piece of the supporting framework of the
lamp, made for the purpose of holding the tube steady.
The tube has a free sliding motion for a short space, that is, upwards, until the nut f touches the under
side of z³, and downwards, until the collar f1 touches the upper side of z³, or rather until it touches the
part q which rests on 2³. The weight of the tube is nearly counterpoised by the elasticity of the spring
q', which is attached to an arm projecting from the tube, as shown, and has an arm q fixed to its other
end, the further end q being forked 80 as to embrace the tube, and to rest the pressure of the spring
upon the top of z³. The weight of the tube being thus supported, it rises with the electrode, when it is
pushed upwards by E', until f touches 23, and after that the electrode rises by passing through the tube.
The parts of the fixed supports c and c", through which the tube passes, may be insulated from the
rest of the framework by collars of wood, as represented by 22 and z³.
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ELECTRIC LIGHT.
437
The following are improved modes of preparing the materials for electrodes: take the powder of
various carbonaceous matters, which make electrodes of different qualities as to illuminating power and
resistance to abrasion by the electric current. The materials preferred are; first, plumbago powder,
having its iron, &c., extracted by washing and warming in acids; second, lamp-black; third, charcoal
powder of sundry kinds of wood; fourth, the powder of the carbonaceous concrete which becomes de-
posited in gas retorts; or, fifth, grains of this latter substance sifted so as to obtain a somewhat uniform
size of grain: any one of these materials mixed with a quantity of brown sugar, in such proportions
as are requisite to form a free paste with the powder when the mixture is melted by heat, a much
larger proportion being sometimes employed for making the product cohere better. This mixture is
melted and boiled (without water) until it becomes stiff; it is then pressed (while hot) into iron moulds
of suitable shapes, the inside being lined with paper, or chalk, or plaster of Paris, to prevent the mixture
from adhering to the mould, and to form a porous envelope through which the gases, &c., can slowly
escape. The moulds have numerous small crevices or holes for the purpose of letting the gases and
steam escape from the material when baked. The moulds when charged and closed tightly are heated
very gradually, so as to allow sufficient time for drying and dispelling the gases without their destroy-
ing the compactness of the material. When a red heat is thus obtained, it is after a time allowed to
subside, when the contents of the moulds are
carefully taken out and placed upright in a
1275.
crucible, which is filled with sand luted down
and gradually raised to a white heat. At
this high temperature they may be kept for
some time, to give them greater mechanical
hardness and strength; they are then covered
up and allowed to cool gently, and being
cleaned if they retain a coating of any other
substance, they are put into close-fitting tin
cases for use.
ELECTRIC LIGHT Apparatus-Straités
patent. Figs. 1275 and 1276. A, copper coil. B,
soft iron bar for raising or depressing" the bal-
ance-lever. C, regulating balance-lever. D,
ratchet-wheel for raising or depressing rack. E,
rack carrying the lower electrode. F, eccentric-
wheel moved by clock-work, for giving motion,
by means of the lever G, to the ratchet-wheel D.
H, end of coil, communicating with the upper
electrode. II, Carbon electrodes. K, clock-
work movement.
The light was produced from a galvanic
battery of moderate size, embracing in its
construction and elements several improve-
ments, so as to render the battery constant,
continuous, and regular in its action, and eco-
nomical in cost. By means of solid copper
wires the electric fluid is conveyed to the
lamp, which may be placed on a table or sus-
pended from the ceiling. In this lamp are
two sticks of carbon or carbonaceous material,
between which the light is developed; and
these sticks are moved by a clock-work ar-
rangement, in proportion as they are con-
sumed, at a speed which is regulated by the
current. To render the light continuous, it is
necessary that these two pieces of carbon
should first be brought into actual contact,
that the current may pass, and then be sep-
arated to a short distance apart. This is ac-
complished by means of the current itself,
without manual aid. As the carbon grad-
ually wears away, (about half an inch an
hour,) the same regulated distance between
the two electrodes is ensured by like means.
The apparatus to effect this self-regulation is
an electro-magnetic instrument, placed im-
mediately under the plate of the lamp, and
through which the current of electricity is
made to pass. The principle of this instrument is extremely ingenious, and in some degree resombles
a galvanometer: the galvanic current passing through a coil of wire, magnetizes a bar of soft iron
which is passed through the coil; and, in proportion as the current is strong or feeble, the magnetized
bar rises or falls. When the current is in excess, it actuates an escapement, and the two electrodes are
drawn to the required distance apart; and when the current passing is less than the regulated quan-
tity, the motion is reversed, and the electrodes are drawn closer together. By these means, not only is
the light rendered steady and constant, but only 80 much of the generated fluid is allowed to pass as is
developed in light-effecting an economy of the battery power never before approached.
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438
ELECTRIC CLOCK.
The light equalled between 800 and 900 standard wax candles and when it was thrown by means
of a glass lens on some pictures, the most delicate tints of color, the grays, greens, and blues, were as
clearly defined as by daylight. The prismatic rays were as vivid and bright as those from a sunbeam,
and perfectly identical in color, showing the light to be, in purity, equal to the sun.
The light was also exhibited immersed in a bowl of water;
and as an illustration of the fact that the light, strictly speak-
ing, was not the result of combustion, (in the ordinary sense of
the term,) but was a pure incandescent light, not dependent
upon oxygen for its support. When in action in a room, it nei-
1276.
ther takes from nor adds to the surrounding air any property
whatever-an important fact in large and crowded assemblies.
The inventor is preparing modifications of his lamps, with a
view to show the applicability of the discovery to every pur-
pose of illumination, from a single candle power upwards.
The cost of the light he stated to be about one-twelfth that of
gas; that it was perfectly safe and harmless and easily man-
aged, and that accidents from explosion or from fire were im-
possible.
1277.
B
ELECTRIC CLOCK. Fig. 1277 is a view
of the electric clock in the telegraph office of
the Eastern Counties Railway, Eng. CZ are
plates of copper and zinc buried in the earth
(with a quantity of coke) a depth of nine feet
this is termed an earth battery It is compu-
ted that the electricity derived from the earth
with the two plates is sufficient to work thirty
clocks, and will last a number of years with-
out being disturbed; EE the pendulum, made
of wood, to the lower end of which is fastened
a coil of wire enclosed in a brass case F; A A
are two permanent magnets; B the balance
weight for regulating the pendulum; M M a
stand supporting N a steel spring by which
the pendulum is suspended; K a spring to
which the wire coming from z is attached
V a piece of wood for insulating the wire
from the stand ; hh two small pieces of
wood; tt two metal pins passing through
the wood hh. one of the pins t is joined to a
brass plate, the other pin has a small gold
head, brought level with a piece of agate S;
n the break for making and breaking the con-
tact; R two arms projecting from the pendu-
lum; pr brackets supporting hh; suppose
the pendulum is set in motion by moving it
to the left, one of the arms R would be
brought in contact with the break, pushing
the point which did rest on the agate S on to
the metal t, the other end of the break would
still rest on the brass plate; the current of
electricity would then pass from 2 up the
wire (as indicated by the arrows) to the
C
spring K, (down one of the wires at the back
Z
F.
o
of the pendulum shown dotted,) through the
coil in box F up the other wire to spring N,
then down the wire to pin t along the break
to the other pin, and terminating at C, the
circuit would then be complete; when in the
EARTH
position described, the coil F would become
a magnet, and be attracted back by the mag-
net A, the other arm would then push the
break on the agate, the pendulum would then
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ELECTRO-METALLURGY.
439
fall back again, making the contact, thus a constant motion of the pendulum is kept up. To complete
the clock, a few wheels are necessary for the proper working of the hour, minute, and second hands.
ELECTRO-METALLURGY. Electro-metallurgy, depending essentially on galvanic agency, is sub-
ject to the operation of the same principles, and governed by the same laws laid down in the books
which treat of galvanism and galvanic batteries; the successful reduction, therefore, of the metals,
must depend entirely upon a thorough knowledge of galvanism, and galvanic apparatus.
Independently, however, of these general galvanic properties, there are certain particular ones apper-
taining either to the different metals, or to the different qualites of the same metals, which have to be
considered in detail, as well as the apparatus to be employed for precipitations.
The substance best adapted for the complete separation of the solutions, in a single-cell apparatus, is
animal membrane. Of this there are various kinds; bladders of different textures, the lining membrane
of the intestine of the ox, fine gold-beaters' skin, or bladders of various animals may be used. Animal
membrane separates solutions better than any other diaphragm, but, for most purposes, it affords too
much resistance to the passage of the current. Brown paper, and cartridge-paper, are frequently of
value for the electro-metallurgist, and they last for a considerable period without renewal. Of late,
earthenware tubes have been very extensively employed.
The following is the order in which different substances stand with regard to their capabilities of
admitting the passage of electricity:
Brown paper,
Bladders of various thickness.
Thin plaster of Paris,
Thick plaster of Paris,
Porous earthenware,
Capillary tube.
Gold-beaters' skin,
Of the various forms of apparatus, which may be used for the precipitation of the metals, the most
simple is that having a porous earthenware tube, to contain the acid and zinc, whilst the negative metal,
which is usually a mould, is placed externally to this, and connected by a piece of wire to the zinc. Thus,
for instance, take a pound pot, Fig. 1278, and half fill it with a solution of sulphate of
1278.
copper, S; in this, place the earthen vessel P, with the dilute acid A and zinc Z, and this
constitutes the whole of the present form of apparatus; for, when we desire to make an
electro-medallion, it is only necessary to place one or more casts in the outer vessel m m
connected by a wire with the zinc, and then action will immediately commence. Any
number of moulds may be placed in the outer vessel, provided they can radiate to the
zinc. Saturation of the liquid may be preserved by suspending some of the salt in a
linen bag over the mould. This form is objectionable, because the salt of zinc speedily
passes through to the outer vessel; but it has the advantage of allowing the mould to be
placed vertically, in which position it is much less liable to have particles of dust settling
upon it. There is no limit to the size of this outer vessel; for a water-butt, a tank, or
even a lake naturally impregnated with sulphate of copper, would answer.
There is another form, where bladder takes the place of the earthen vessel, and where
the position of the cast is horizontal. Here, the outer vessel, Fig. 1279, which is square, is
made of wood, coated internally with cement; on one part of the edge of which, a piece
of brass b is fixed in which are two holes, one for connection with the wire of the cast m, the other with
that of the zinc. In the interior of the trough, a moveable shelf of mahogany is placed, on which is
supported a glass containing a zinc plate Z and crystals of sul-
phate of copper to be dissolved. The glass has a piece of blad-
1279.
der tied over the rim, and this forms an outer vessel similar to
the porous tube in the former apparatus. It, in like manner,
contains the acid and zinc; the latter being connected by a
screw to a wire, in such a way that it can be readily removed.
In every single-cell apparatus, the solution of metallic salt
should be maintained in the required degree of concentration,
by keeping some crystals of the salt undissolved in the solu-
tion. If these crystals are allowed to sink to the bottom of the
vessel, they will not answer the intended purpose of maintain-
ing a saturated solution; for the portions of the fluid which
have been deprived of their metallic salt rise to the surface, whilst the saturated parts remain in con-
tact with the crystals at the bottom, thus preventing their solution. This difficulty may, however, be
readily overcome, by placing the crystals to be dissolved in a little bag, on a shelf at the top of the
liquid, by which means the saturation of the fluid will be ensured.
The only circumstance to be observed is, that the zinc be equidistant at every place from the metal
on which the reduction of the new metal is to be effected, 80 that the deposite may be everywhere
equally thick.
There are other metals besides zinc and iron that might be used to generate electricity thus, lead
will reduce copper, silver, gold, and various other metals. When it is employed for electro-metallur-
gical experiments we must form a soluble salt, of which the acetate and nitrate are most conspicuous.
If we use nitrate of potash in the outer side with the lead, and a solution of metallic salt, say of copper,
in the inner side, with the negative plate, the reduction will take place. It is vain to attempt to reduce
a sulphate by this salt, for the sulphate of lead is absolutely insoluble. Its equivalent number is very
high, one hundred and four of lead being equal to thirty-two of zinc, which is one serious objection to
its use.
Tin may be used to generate electricity, it being soluble in muriatic, sulphuric, acetic, oxalic acids,
&c. It has a feeble force, requires a large plate, and thin porous tube. It is best used with dilute sul-
phuric acid on one side, and the metallic salt, which should be a sulphate, on the other. It reduces
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several metals, but, unfortunately, has a high combining number, requiring fifty-eight grains to generate
as much power as thirty-two grains of zinc.
A solution of a salt of copper is to be placed in a convenient vessel, Fig. 1280, and the object N, on
which the precipitation is to take place, is to be connected with the zinc of the battery Z, whilst a piece
of sheet copper is connected with the silver S. As soon as action commences, water is decomposed,
oxygen passes to the copper pole and oxydizes it, and the hydrogen passes to the negative plate. Whilst
the decomposition is taking place, oxide of copper is passing to the negative pole, and the acid to the
positive pole; the hydrogen reduces the oxide of copper at the negative plate, whilst the acid combines
with oxide of copper at the positive end, and thus the saturation is continued.
1280.
1281.
S
N
S
Z
S
S
A series of precipitating troughs, arranged like a compound battery, may be employed occasionally
with only one battery. In this case, we should have one generating cell in the battery, and six, eight,
or ten decomposition cells; therefore, by the fundamental laws to which the action of the galvanic fluid
is obedient, we should have six, eight, or ten equivalents of metal reduced for one equivalent of zinc.
Theoretically, this apparatus, Fig. 1281, exceeds every other in economy-practically, it has not been so
much employed as it ought to be, particularly in the reduction of plain copper plates. The galvanic su-
ries is made by alternating the metal C to be dissolved with the object m to receive the precipitate, the
last mould being joined to the zinc Z of the battery, and the last copper with the silver S; the positive
plates should be large, and the liquid rendered as conducting as possible to lessen resistance. It is im-
portant in this apparatus that every positive and negative plate should possess nearly the same surface,
and the solution the same strength, in order that the metal of the same quality should be reduced in
each cell.
Description of Fig. 1282.-A, the battery cell,
M
extending downwards 2 feet under the floor, and
terminating in a point, in which a stop-cock is
fixed, to draw off the saturated solution of sul-
phate of zinc, which is formed there. The bot-
h
tom is reached by a trap-door and steps.
1282.
B, the decomposing trough, resting on a keel,
D
which, for the purpose of agitating the solution,
enables a rocking motion to be given to the
S
g
trough, by means of a coupling shaft a connected
with the truck b on which the trough is moved
to any part of the room, for cleaning or changing
the plate.
K
CC, conductors from the battery plates, each
formed of five lengths of copper wire 1-10th of an
inch in diameter, twisted together, and covered
with water-proof tape, the one leading to the pos-
h
itive or dissolving plate c, the other to the nega-
tive or receiving plate d, the latter being placed
C
on a board, with small feet or wedges, to keep it
A
at the proper distance from, and parallel to, the
positive plate.
D, a water-tight box containing a solution of
sulphuric acid in the proportion of 1 to 4 water,
by which the battery cell (having been originally
charged with solution of the requisite strength,
1 to 30) is constantly supplied with renewed acid,
through a lead pipe e which extends downwards
into the cell about 2 feet, and is turned horizon-
b
tally 80 as to cause a circulating movement in the
solution. The box is provided with a float f to
indicate the height of the acid solution in it, and
the quantity which has passed into the battery.
In Fig. 1282 the acid box is placed near the
battery cell for the sake of bringing it within the
margin lines. It is nearly close to the ceiling, in
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reality, so as to afford by its height a considerable force to the solution issuing from the pipe, that it
may circulate freely around the battery plates.
For want of height in this Figure, it has also been necessary to omit a beam which passes along the
side of the room nearly close to the ceiling, on which a small carriage and pulley travel, for the purpose
of raising the plates and moving them to any part of the battery range.
E, a gasometer, or gas collector, formed of thin copper, suspended by the wires g and the cord 12, which
passes over the pulleys i i, and terminates in a counterpoise k, intended to balance in part the collector.
which is placed immediately over the plates in the battery, and dips into the solution. It is furnished
with a stop-cock I, through which the gas passes by the flexible tube m and copper pipe n to a gas meter o.
F G, levers-the former, F, being attached to the plug of the stop-cock, having at one end a weight
p and at the other a chain q fastened to the battery cell; the latter, G, turning in the same centre, and
brought by a screw r at one end into contact with the under part of the former, F, and kept in con-
tact with it by the pressing of the weight p. To its other end a small block of wood s is attached, dip
ping into a waste-box t, and acting as a weight when the box t is empty, and as a float when the box
is filled by overflow from the battery cell.
H I, levers, drawn downwards by the weight of the collector, with which they are connected by the
cord и. The former, H, turns on a pivot at the end of the latter, having at its other end a cord carrying
a weight v which acts in the same manner as 8; the latter, I, carrying, as before mentioned, the lever H
at one end, and having at the other end a spring w screwed to it, from which a wire, passing through
the lever, deseends to the valve x for the purpose of raising the valve suddenly, being first closed upon
the lever, until the adhesion of the valve to its seat is overcome, when the spring returns to its former
position with a jerk, carrying up the valve, and opening the aperture at once to its greatest extent.
K, a lever fixed to the bottom of the box D, having at one end a small hole through which the cord /
passes, until checked by a knob y, when the other end rises and lifts a valve 2 in the bottom of the box t.
Working of the apparatus.-The operation proceeds in the following manner. The aperture of the
stop-cock 1 must be 80 adjusted by the screw r as to allow the gas evolved from the plates of the bat-
tery to escape at the same rate as that at which it is generated, allowing a slight excess to resist the
uncounterpoised portion of the weight of the collector, or its tendency to sink down. Then, when the
quantity evolved is greater than can pass through the aperture, the collector will ascend till the lever
F is restrained by the chain q, when the aperture will be enlarged till equivalent to the quantity
evolved. On the contrary, when the quantity evolved is less than that for which the adjustment has
been made, the collector will descend and pull down the levers H and I; the weight v will resist the
end of the lever H, and the end of the lever I carrying the spring w will rise, and with it the valve x of
the acid cistern, with a jerk; a quantity of the strong acid solution will then rush into the battery cell
by the pipe e, with sufficient force to circulate round the plates, displacing a portion of the lighter or
less acid solution, which will run off by the overflow pipe o into the box t, which thus becomes a meas-
ure of the quantity of acid thrown into the cell. When the lever H then becomes released from the
weight of the float v, the acid valve x preponderates, falls into its seat, and stops the supply. At the
same time, the lever G of the collector is also released by the floating of the weight 2, and the aperture
of the stop-cock completely closed by the weight p. The gas collector in this condition rises rapidly,
till the knob y comes into contact with the lever K, when the valve 2 opens, and the solution in the
waste-box t runs into a vessel placed for its reception, where its deficiency of acid is supplied, and it
again returned to the cistern D. The waste-box t being emptied, the floats 8 and v again descend to
the bottom of the box 8, carrying down the lever G, by which the aperture of the stop-cock is opened,
and the apparatus is again in a position to throw in a greater supply of acid, if the energy of the bat-
tery is not sufficient to evolve the quantity of hydrogen for which the aperture has been adjusted. Thus
the power of the battery depends on the stop-cock, whose normal position is adjusted in the first instance
to the required openness by the screw r; and the state of its working is ascertained by the quantities
of gas which pass through the meter in equal times.
The voltaic deposite of metal may take place upon any conducting substance, which is capable of
acting the part of the negative metal, in the arrangement. The laws which relate to this, are the same
which regulate, in a similar manner, the plates of the battery. The deposite may be effected upon most
metals, except the earthy and alkaline, and upon any alloy or compound of them. It may, likewise,
take place upon charcoal and plumbago.
The following is a short list of substances which may be used to receive the deposite of metal
Carbon
In all metallic solutions, acid,
Lead
In all alkaline, in all but the
neutral, or alkaline.
preceding, saline and acid.
Platinum
do.
do.
do.
Bismuth
do.
do.
do.
Gold
do.
do.
do
Antimony
do.
do.
do.
Palladium
do.
do.
do.
Tin
do.
do.
do.
Silver
In all alkaline, in all but the
Iron
do.
do.
do.
preceding, saline and acid.
Zinc
In some alkaline
do.
Copper
do.
do.
do.
Non-metallic substances.
Sealing-wax
In all saline or acid solutions; not in alkaline.
White wax
do.
do.
do.
Beeswax and rosin
do.
do.
do.
Stearine
do.
do.
do.
Spermaceti
do.
do.
do.
Plaster of Paris, prepared
do.
do.
do.
Some animal substances
do.
do.
do.
Most vegetable substances
do.
do.
do.
56
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ELECTRO-METALLURGY.
Now by the preceding table we perceive that some substances may be immersed in one solution
with impunity, while others would be destroyed by its action on them. It is, therefore, important to
know, when we have a substance which is acted upon by any metallic solution, how to make a reverse
from it that shall not be injured. For convenience a table is appended, showing at one view the modes
of preparing moulds of different substances. The perpendicular row is a list of the objects to be copied,
the horizontal the means of multiplying them. Suppose the operator had a valuable silver medal, of
which he was desirous of making a fac-simile, he would look in the table against silver, and would there
find that he could make a mould, or reverse, in copper, by electro-metallurgy; but to this he would
doubtless object. He would then see by what other methods he could also make a mould, and he would
find that he could succeed with each of the processes given, and perhaps he would prefer plaster of
Paris, as least likely to be injurious to his medal. Having made the mould in plaster, he would see
from the former table, that when prepared it might be placed in any saline or acid solution of copper,
to form the fac-simile.
LIST OF THE PRINCIPAL MODES OF MAKING MOULDS OR REVERSES OF VARIOUS OBJECTS.
STEARINE,
SEALING-
SPERMACETI,
PLASTER OF
METALS.
COPPER.
LEAD.
ALLOYS OF LEAD.
SULPHUR.
WAX.
WAX AND
PARIS.
COMPOUNDS.
Copper
by Electro-
by percussion,
Metallurgy.
rolling.
by clichee.
by fusion.
by fusion.
by fusion.
by mixture
with water.
Silver
do.
do.
do.
do.
do.
do.
do.
Gold
do.
do.
do.
do.
do.
do.
do.
Platinum
do.
do.
do.
do.
do.
do.
do.
Lead
do.
do.
do.
do.
do.
Alloys of
do.
by clichée.
do.
do.
do.
Tin
do.
do.
do.
do.
Iron
do. by Per-
by percussion,
cussion.
rolling.
by clichée.
do.
do.
by fusion.
do.
Other Metals
by Electro-
do.
do.
do.
Metallurgy.
Sealing-Wax
do.
by percussion.
do.
do.
Beeswax and Com-
do.
do.
pounds
Stearine
do.
do.
Spermaceti
do.
do.
Sulphur
by clichée.
by fusion.
by fusion.
do.
Bread-crumbs
by fusion.
do.
Plaster of Paris
by Electro-
Metallurgy.
by clichee.
by fusion.
by fusion.
do.
Glue and whitening
not.
do.
do.
do.
Animal subs
by Electro-
Metallurgy.
some by clichée.
{ some by
do.
fusion.
by fusion.
do.
Vegetable sub
do.
do.
do.
do.
do.
do.
Gum
do.
Isinglass
do.
Siliceous bodies,
by Electro-
as Glass
Metallurgy.
by clichée.
by fusion.
by fusion.
by fusion.
do.
Aluminous do
do.
do.
do.
do.
do.
do.
Carbon, from its cheapness, from its indestructible nature, and from its being unaltered in all metallic
solutions, is invaluable for electro-metallurgy. One variety of it, graphite, or plumbago, usually called
black-lead, has a most extensive application, which we shall hereafter have occasion more especially to
describe.
Platinum, from its being unaltered by any solution, holds an important place for the reception of
every metal its great price, however, must always be an impediment to its general use.
Gold is equally valuable with platinum, but is still more expensive; yet when extended to that state
in which it exists as gold-leaf, it may be applied over the surface of any soft substance, and thus a me-
tallic surface is presented. This plan may be employed with other metals, such as silver or tin; but
we have other methods which render all these modes unnecessary.
Silver only reduces gold, platinum, palladium, and two or three more metals from these acid solu-
tions, and therefore may be employed as a negative one for the reduction of metals. Silver-leaf of a
thickness of about one square foot to the ounce, and made of pure metal, is much used by the forgers.
The process they adopt is, to place the coin to be copied on a piece of wood, and upon the coin they
place a piece of this thin silver. They beat it gently with a wooden mallet, till a perfect impression is
taken on the metal, a result soon obtained. They then copy the opposite side of the coin in the same
way. The two impressions are then soldered together, and the manufacturer sallies forth and risks his
neck for the illicit shilling which has cost him this labor. The reader will doubtless have no inclination
to practice this fraud, and, therefore, it is unnecessary to enter further into the process; but it should be
borne in mind, that the same means may be employed with a better intention by the electro-metallur-
gist, to obtain a mould.
We have now to treat of the alloys of lead, tin, bismuth, antimony, and zinc, which demand especial
attention, because there are means of casting these alloys, and of making reverses, moulds, and medals,
by more ready methods than we possess for any other metals. It has been remarked that these alloys
have melting properties, not only below the mean of the melting points of the respective metals which
compose them, but even some of them considerably below the fusing point of the most fusible metal
that enters into their composition. To some of these alloys we owe the manufacture of type, to others
the process of stereotyping, to others that of polytyping or clichée. The composition of the type-metal
is stated to be 1 part of lead to 16 of antimony, and sometimes a portion of copper is added this pro-
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443
portion probably varies at each foundry as they generally consider that part of the business a secret
Other compositions are given, as 6 to 2, 4 to 5, or 4 to 1 of antimony to lead. In the foundry there are
a number of crucibles, each heated by a charcoal fire, one being allowed to each workman. To make
a type, the operator takes a little of the melted alloy in a small ladle each time, and pours it into the
mould which has the counterpart of the letter he wishes to make. The moment it is in the mould, he
carries it suddenly upwards with a jerk, above his head, by which means the metal is forced into all the
fine parts of the work, and a good impression is insured. Now we might expect that those who day by
day work at this occupation, would attain to certainty in their proceedings; but this is by no means
found to be the case, for they form a very large number of imperfect types which are obliged to be re-
melted. I give this process to show that with those about to be detailed a strong analogy to coining is
presented. In the first case, it is with a fluid, or semi-fluid, metal; in the last with a solid mass. The
alloys which may be used for these purposes are very various, according to the object from which we
desire to obtain a reverse, for as a great latitude is allowed in the fusing point, 80 at one time we prefer
the more fusible, at another that which melts at a higher temperature.
The following is a list of alloys which are employed by various authors, to which should be added all
the compositions of type-metal last described, and as antimony possesses the property of expanding in
the act of cooling, its alloys are well adapted for casting.
Tin.
Lead. Bismuth. Zinc.
Tin.
Lead.
Bismuth.
Zinc.
1
4
1
0
0
5
3
5
8
0 fuses about 212° Fah.
2
5
10
1
0
6
1
1
2
0 said to fuse at Fah. 200.
8
0
1
1
0
7
1
2
8
0
do.
200.
4
1
1
o
0
8
1
0
1
1
do.
200.
All these compounds are used at a point between the fluid and the solid state, for at that heat they
assume a pasty appearance, which is probably caused by the alloy consisting of two parts, one more
fusible than the other. In fact, if we examine the mass very attentively, it appears to be composed of
a quantity of perfectly solid metal in a fine state of division suspended in another portion of alloy per-
fectly fluid. Having obtained our alloy in this state, it is ready for the process of making our reverse,
and this process is termed the clichée. The alloy marked 1, 2, 3, 4, as well as the compositions for
type-metal, will answer for iron, brass, copper, or other hard substances; perhaps No. 2 and No. 3 will
be found, after type-metal, entitled to the preference. When we desire to clichée from wood, sulphur,
or from another clichée, we must employ those alloys which fuse more readily, and Nos. 5, 6, 7, and 8
come into use. If hard metals are used from which to clichée, we should take care to clean them tho-
roughly before using, and always employ them in a cool state. In using one clichée for making a
second, we must take care to employ a less fusible alloy for the first than for the second; thus the type-
metal and Nos. 1, 2, 3, 4, answer as a primary mould to make casts in 5, 6, 7, 8. To clichée from plas-
ter of Paris, the material must be prepared either by linseed oil, gum, or gelatine, which processes will
be described when treating of those substances, and sulphur moulds must be employed within a few
hours of their manufacture.
The simplest mode of making a clichée is to pour a little
of the fused alloy on any flat surface, then to skim it clear
with the edge of a card that the surface may be most per-
1283.
fectly bright, after which we should wait till it is nearly at
the point of cooling, when with a considerable jerk the ma-
trix is to be brought down upon the alloy, by which opera-
tion the fluid part will be forced out in all directions, and a
reverse, equal in polish, sharpness, and beauty to the original,
will be instantly obtained. If the alloy is used too hot, the
surface is apt to present a crystalline appearance; it is there-
fore very important that the object should be cool enough to
make the alloy perfectly hard, as soon as the blow has driven
the metal into all the finest lines. When taking a clichée
from an intaglio the air has not always time to get away, in
which case little holes or bubbles are very apt to be caused.
The surplus metal round the edges of the mould so formed
is then trimmed off in a lathe; but this operation is generally
unnecessary for electro-inetallurgy.
The Italians have a method of taking very perfect moulds
with these alloys. They take a portion of the melted mass,
and place it on a piece of paper; upon this they lay the
medal, and under both a piece of carpet; upon the medal
they place a log of wood, and then a sharp blow on the wood
will ensure the sharpness of the cast. The worth of a cast
thus made, is from sixpence to half-a-crown. I have before
mentioned that clichée is nothing but a process of coining, and
sometimes a sort of coining-press is used for these purposes;
the medal or other object is fixed either by mastic or by
screws on a piece of metal A, Fig. 1283, which descends with
force on the semi-fluid alloy. Previously to the operation of striking, the object is suspended by a cord
passing through a ring, and attached to the rod of iron connected with the piece of metal A. When
every thing is ready, the doors are shut and the cord let loose, which allows the object to fall with great
force on the metal.
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An impression may be given to a perfectly clean bright surface of sheet-lead, by placing upon it the
object to be copied, and then with a steady hand dealing a heavy blow. By this mode even a sealing-
wax impression may be copied, although this, at first sight, would appear hardly credible. By pres-
sure alone, it would be difficult to obtain the result which can be given by the blow. Rolled lead, first
scraped, in order to remove any oxide from the surface, and then flattened by running it through a press
upon a polished iron plate, will readily take the impression of the most delicate work or engraving.
The object to be copied is simply to be placed upon the lead, and then the two are to be sent once, and
once only, through the printing-press, as in the ordinary operation for taking a print. The pressure in
rolling is far greater than can be given by direct pressure, though there are instruments used by em-
bossers capable of exerting great power. The disadvantage of forming moulds by rolling is a liability
of distortion of the image from imperfect stretching of the metal.
Non-conducting substances are of three kinds: substances having no affinity either for the metal or
the solution; substances acted upon by the solution; and, lastly, substances capable of combining with
the metal thrown down. Those of the first class are by far the most valuable, but are not very numer-
ous. The best of these is sealing-wax-a composition of shell-lac, Venice turpentine, and coloring mat-
ter. Dr. Ure gives, as the proportion in which these are used, four, one, and three. The manufacturers
have several varieties, the most expensive of which is the best for making seals. Some of them are
extremely hard, as for example, a black wax which is used for filling up the letters in the engraved
plates of shop windows; but I do not know how a difference of composition can affect the properties of
the wax in this important manner. The use of sealing-wax is attended with considerable expense, as
good wax cannot be purchased under three and sixpence or four shillings a pound, but it takes impres-
sions of objects of the greatest delicacy with the utmost accuracy. Every one uses this substance, and
sealing is one of those operations in which every one thinks that he excels his neighbor in the manner
in which he performs it; but, however well satisfied he may be with his skill in the small way, yet the
management of large seals is attended with great difficulty and uncer-
tainty. Proof-seals are made by engravers, by holding a piece of card
over a flame, and rubbing, gradually, a stick of wax, previously softened
by heat, upon the heated card, till a sufficiency is obtained, when the coin
1284.
is to be pressed upon it. Very large seals are made by taking a good-
sized stick of wax, and holding it in a flame, not only till the point, but
even three or four inches of its length are lighted. It is then to be held
over a piece of paper or card, when large drops of melted wax will keep
falling, and in a short period a considerable quantity will be melted. The
flame of the stick is to be blown out, and the fluid mass well stirred
round and round, till all the air-bubbles are dispersed, and a clear sur-
face of semi-fluid wax is exposed. It is now ready to receive the impres-
sion of the object of which we are desirous of obtaining a copy. This is
to be laid upon the wax, and pressed with considerable force, and lastly
plunged into cold water, 80 as to cool it suddenly. Much less difficulty
attends the use of a metallic die, for that abstracts the heat, and does not
adhere. The accuracy with which sealing-wax takes impressions with care, is shown by its copying the
lines on mother-of-pearl, and analogous substances which naturally possess the property of decomposing
the rays of light; and the same colors which exist in the original are also to be observed in the copy.
When we are desirous to obtain an impression in wax from wood or similar substances, they should
be previously brushed over with a little salad oil. In these cases, by plunging the wax into cold wa-
ter, its surface is apt to sink in places, and thus becomes uneven. Very large seals have been made of
sealing-wax, by means of placing the mould on the semi-fluid composition, and subjecting it to hydro-
static pressure.
White wax may be used for taking casts, and can be procured with least expense by buying the
waste ends of wax candles, which may be readily melted over a lamp. The object to be copied is to
be very lightly oiled with a hog's-bristle brush previously dipped in that fluid. A moment's exposure
of the medal to a current of steam, or even to the breath, will answer the same purpose, because a film
of water, for which wax has no affinity, covers the medal, and therefore causes a separation between
the wax and the metal.
Electro-gilding, Plating, dc.-The infilming of one metal by another is a subject of much interest, and
the process has received different names according to the metal employed for that purpose. Thus,
when gold is used, it is termed gilding; when copper, coppering; silver, silvering, or plating, &c. In
every one of these cases we have to be careful that the two metals adhere, and for this purpose we take
means to prevent any film of air, oxide, or any non-conducting substance, from remaining on the first
plate, as that would cause a separation between the metals. We apply heat, we scour the plate, or
where it is possible, we slightly act upon the surface of the metal to receive the new deposite, taking care
thoroughly to wash the metal after this operation.
Electro-gilding is, in most cases, remarkably easy, for if care be taken to follow the laws which
have been already detailed, it will be attended with very little trouble. The metal to receive the gold
may be either platinum, palladium, silver, copper, carbon, gold itself, or indeed almost any other metal,
when the auro-cyanide of gold is employed. The surface should be chemically clean, and freed from
adherent air, either by plunging it into nitric acid or a solution of potash, or by heating it and then
quenching it in acid. The smoother the surface the more favorably the deposite will take place upon it,
for a very rough surface is not quite 80 well adapted for these operations, the hydrogen having a greater
tendency to be evolved from it. When the metal to be gilt does not decompose the solution of gold,
the solution may be stronger. When, on the contrary, the metal acts upon the solution, it must be
weaker. The electrical current must be suited to these varying circumstances, and in general but a
feeble current is required.
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For all cases of electro-gilding the auro-cyanide of potassium makes by far the best solution. It is
scarcely decomposed by any metal. It may be prepared by digesting oxide of gold in a strong solution
of cyanide of potassium. For our present purpose, a strong solution of the
1285.
salt is to be preferred, and, from the corrosive nature of the cyanide of po-
S
2
tassium, it should always be placed in a glass vessel. For gilding, the single-
battery process will answer every purpose where time is not an object, and
is indeed as a general rule to be much preferred; but if great speed is
required the compound-battery, made of two, three, or four batteries, must be
employed, or more cyanide of potassium must be added to the solution of
gold. The size of the battery need never exceed the size of the object to be
9
gilded, though if it be larger it will not be of any material consequence, as a
strong obstacle to the passage of the current is situated at the positive gold
pole. The positive pole, as a general rule, should consist of a piece of pure
gold flattened, and the part exposed to the solution should not exceed the size of the object to receive
the deposite.
Every portion of the object on which we are desirous to have no layer of gold, must be coated with
tallow, wax, or any other non-conducting substance, the presence of which will prevent any deposite
from taking place on those parts. In this way an object may be coated to any desired limit, or upon
any circumscribed parts of its surface, as, for example, drawing or writing thereon. The rapidity of the
process may be regulated to the greatest nicety by placing more or less of the positive plate of gold in
the solution, by which means, as in other cases, the quantity of electricity passing may be regulated
with the utmost precision.
The time occupied for the process must vary according to the amount of electricity passing, and the
quantity of gold required to be deposited; but the thickness of the deposite can at any time be learned,
either by ascertaining the additional weight it has received, or by the reduction which the positive gold
pole has suffered.
To conduct this elegant process with the greatest economy of time, the quantity of electricity should
be so regulated to the strength of the metallic solution, that the hydrogen is kept below its point of
evolution from the negative plate; for we must always bear in mind that the evolution of hydrogen is
attended with evil, as the precipitate will then be in one of the finely-divided states, or even as a black
powder.
During the process, particularly if the object have a rough surface, it is a good plan to remove it from
the solution before the completion of the process, and rub it with a hard brush and a small quantity of
whiting or rottenstone and well wash it; by these means any finely-divided metal will be removed, and
the gold will be precipitated in a very even manner. This cleansing is not required when the deposition
takes place very slowly from the auro-oyanide of potassium. The color of the gold, if the precipitated
layer be very thin, will be a greenish yellow, but when thicker it will be the natural color of the pure
metal
The state of the surface of the reduced gold varies with the rapidity of the process, in relation to the
strength of the metallic solution. If reduced very slowly, it will assume the beautiful frosted appear
ance of dead gold. If deposited more rapidly, the surface will have a brighter appearance. If still
more rapidly, the surface will again begin to be brown, and quicker than this the operator must not
conduct his process; for then the spongy deposite begins, which the electro-gilder should shun as the
very bane of his art.
All objects of silver may be readily gilt in this way, and objects of copper with as great facility as
those of silver. Some suppose, and, perhaps, with good truth, that copper articles require less gold than
silver ones; the silver, when heated, having the property of taking into itself a certain portion of gold.
However, copper is more difficult to bring into a thoroughly clean state than silver, especially in deep
crevices. For those cases it is better to plunge the copper article into some acid solution of a metal
which it can spontaneously reduce for instance, into dilute sulphuric acid, containing a trace of either
nitrate of silver, chloride of platinum, palladium, or gold, the object of which immersion is not in any
way to leave a deposite of the new metal upon it, but thoroughly to cleanse the surface. After this
immersion the object may be washed, and as much of the reduced metal as possible rubbed off by
means of a hard brush, when it will be found to possess a surface admirably adapted for the reception
of the gold.
If we have a number of small articles to gild, we may suspend them in the solution of gold opposite
to the positive pole; and especial care must be taken that each part of the object is exposed for the
same length of time opposite to, and at the same distance from, the positive pole; for any variation in
this respect would cause a different thickness of gold to be deposited. The workman may be well
assured, that if any article has an unequal coating of gold, it is owing either to some of the above
causes, or that a different relative amount of the positive plate of gold radiated to the various parts of
the object.
An imperfect layer of gold betokens imperfection in the cleansing of the object before immersion.
Electro-gilding is applicable from the finest platinum wire to any object however large, and no doubt
the dome of the Capitol could be gilt as readily as a silver thimble if any person could place it in a
proper apparatus.
Whatever be the object to be gilt, it is highly important that every part should be entirely
immersed in the liquid, or else that part at the junction of the air and water might be liable to be
rapidly dissolved.
The extent to which gold is applied to silver and copper articles is very great, and no variation is
required in the process, except in those cases where the object itself may form a decomposition-trough-
as silver vases, the bowls of large ladles or spoons, where it is only necessary to fill them with the
solution of the auro-cyanide, which in this case should contain no free cyanide of potassium; connecting
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them by means of a wire with the zinc of a battery, and inserting a plate of gold in connection with the
silver of the battery in the interior of the solution, taking care not to allow the gold and vessel to form
a metallic contact; but even in these cases it is far better to immerse them entirely in the liquid, for
reasons before stated. All these cases of gilding appear to be rather for appearance and beauty than
utility; but sometimes metals are coated for the protection which the coat of gold affords: thus the
hair-springs of chronometers have lately been gilt by this process, and patents have been taken out for
its application-a circumstance to be more fully considered when treating of the history of electro-
metallurgy. The gilding of iron and steel only differs from gilding silver and copper in the necessity to
be careful to overcome the difficulty which occurs in most thoroughly cleansing the iron. It should be
plunged into dilute sulphuric acid, and allowed to remain for a short time in that fluid before being
immersed in the auro-cyanide; and if we wish most thoroughly to protect the metal from the action of
extraneous causes, a tolerably thick layer of gold should be used. I am informed that the application
of heat to the auro-cyanide favors the adhesion of the metals.
Sometimes the operator is desirous of having his object bright, either entirely or partially, so
1286.
that the bright and dead parts may form a contrast with each other. In this case the object is
b
dipped into a solution of soft-soap, to which a little prussic acid is added, thoroughly to cleanse
it, when an instrument called a burnisher, b, Fig. 1286, which is nothing but a bright piece
of steel, the shape of which is suitable to the object to be burnished, is rubbed over it two or
three times; and finally the process is completed by a blood-stone 8 fixed upon a handle.
The operation of burnishing is generally performed by women; and it is indeed remarkable
that they should have learned the use of prussic acid for cleansing gold, which has been
employed for many years, especially when we consider that the fact was not known to
chemists at the time. It is worthy of remark, that the solution of soft-soap and prussic acid
is admirably adapted for cleansing trinkets and all articles of gold when they have become
dirty.
The process of gilding by galvanic precipitation from a solution of gold, is very different
in its effects from the method formerly patented by Elkington, termed water-gilding; by the
latter process the metal which is to be gilt is dissolved in an equivalent proportion to the
gold deposited, and therefore as soon as a mere surface of gold is obtained, it has been sup-
posed that no further deposition can take place; but when the gilding is effected by the galvanic
battery, any amount of gold may be applied upon the object; a consideration of no small importance,
as upon the thickness of the coat must depend the durability of the gilding.
It is not the solution of nitro-muriate of gold which is used for water-gilding, but a solution of the
oxide of that metal in potash. The solution may be prepared by adding caustic, potash, or its car-
bonate, to the ordinary solution of gold, in such proportion that the precipitate first formed is redissolved
when it is fit for use. To gild any article, it is plunged, after being first thoroughly cleansed, into the
hot solution, and allowed to remain in the solution till a thin coating is obtained, at the expense of a
small quantity of silver.
Platinating metals by the galvanic current is a new feature in science. The process is similar in all
respects to gilding, but is more difficult. The best solution to be employed is the nitro-muriate of
platinum, to which sufficient soda is added to render it neutral. The object to be coated should be
smooth, and thoroughly cleansed by potash before the process is commenced. Having proceeded thus
far, and the solution of platinum being ready, a fine platinum wire, in connection with the silver of a
compound battery, must be placed so as to dip into the solution, but must not be immersed beyond a
very short distance. The object to be platinated is now ready for connection with the zinc of the
battery after this is effected it is to be dipped in the solution, Fig. 1287. Immediately oxygen gas
will be given off from the platinum wire, in connection with the silver. From the copper or other metal
to be platinated, no gas will be evolved, provided too much electricity be not generated. In a few
minutes the object will be coated with platinum.
This process must not be confounded with that by which negative metals are prepared for my
battery for in this case the platinum is precipitated of the color and appearance of platinum, but in
the latter case it is thrown down as a black powder. The first process I propose to name platinating,
in contradistinction to platinizing. To platinize metals we use a strong current to throw down the metal
in the black powder; to platinate we may employ solutions of any strength, but we must use more
moderate currents, so that the electricity is insufficient for the production of hydrogen.
There is no process at the present time more readily conducted than electro-plating. The best
solution which can be used is without doubt the argento-cyanide of potassium. It is generally made by
boiling the oxide of silver in a strong solution of cyanuret of potassium. The process which is most
favorable is the single battery. The solution should be placed in a glass vessel, and used with a silver
positive pole, about the same size as the object to be silvered. The same precautions should be taken
and the same measures observed with regard to plating as gilding. The object
should be clean, in order that a most perfect adhesion may be effected between
the object to be silvered and the reduced metal The silver will be thrown
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down in somewhat different states, according to circumstances. If thrown down
very slowly, it will assume a beautiful dead appearance; if still more rapidly, it
will be brighter. It is, perhaps, as well to use the solution as strong as possible,
and take care to stir the liquid occasionally, in order that a proper diffusion of
the metallic salt may take place. As a precipitating-trough either the vertical
or horizontal may be employed, according to circumstances; the latter is to be
preferred for large surfaces, as waiters, and similar objects; in which case a
corresponding large plate of silver should be used as the positive pole and
placed over the object to be silvered. Sometimes a large circular silver posi-
tive pole may be made to surround the object, as in the adjoining wood-cut. The
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silver pole is to be connected with the silver plate of a battery, exposing nearly as much surface as the
object to be plated, while the object to be plated is to be connected with the zinc. A little free cyanuret
of potassium, added to the argento-cyanide of potassium, hastens the process by increasing the solu-
bility of the positive pole. The quantity of metal reduced can be readily ascertained, either by fiuding
the additional weight of the object receiving the deposited silver, or by ascertaining the deficiency of
the positive pole.
Plated articles may be either partially or entirely burnished in the same way as gilt objects, according
to the fancy of the operator; and the contrast of dead silver with the bright polished metal much
increases the beauty of the object. Copper and its alloy are most readily silvered by this process.
Non-conducting substances can be silvered by first black-leading them, then attaching a wire in such
a way as to come in contact with the plumbago. In this case we should be careful to use rather a
larger plate of silver than the object, as that favors the growth of the metal, but as a general rule it
would be preferable to coat the object first with copper and then silver it.
Electro-plating is of considerable advantage to the operator, for articles may be made entirely of
copper, and even finished with laborious minuteness, and then silvered. The probability is, however,
that electro-plated articles will not wear quite so well, in proportion to the thickness of the metal, as
ordinary plating, for all metals reduced by electricity are found not to resist attrition so well as rolled
metals. Electro-plating is a cheap process, independently of the intrinsic value of the silver used.
A pretty application of the art of coppering is suitable to horticulturists, as by its means fruits, vege-
tables, leaves, seeds, and various other specimens may be coated with copper, either for ornament or
for the purpose of illustrating the size, form, and other peculiarities of the object. Apples and pears may
be very readily coppered; they are to be brushed over with black-lead, and then
1288.
a small pin is to be thrust in at the stalk; to this a wire should be attached, which
s
is connected with the zinc of the battery. It may then be placed in the solution,
and the whole arrangement completed by the insertion of a piece of copper, which
is to be connected with the silver of the battery. In a similar manner cucumbers,
gourds, potatoes, carrots, and a hundred other vegetables, seeds, and roots can be
covered. Fig. 1288 exhibits a bunch of grapes submitted to the action of the fluid
to be electro-coppered. The form, after the process, is characteristic, and marks
so strongly the individual character of each variety, that the horticulturist is at no
loss to distinguish the specimens at once.
A beautiful effect of metallic surfaces may be obtained by the deposition of
crystallized metal on baskets. The wicker-work must be black-leaded, and con-
nected by means of a wire to the zinc of a galvanic battery; when on being immersed in the metallic
solution, and the circuit completed, it will be covered with the most beautiful crystals of copper,
sparkling in the light from the facets of thousands of little crystals. It is well to pass a very fine
copper wire round several parts of the basket, 80 that it may touch the black-lead in several places, for
this will ensure the coating being more rapidly complete.
In fact there is nothing organic or inorganic which will remain in a solution of salt of copper a few
hours, that may not be coated with the metals.
The foregoing electro-coppered objects are trifling compared to the purposes to which electro-cop-
pering has been tried; for actually, experiments have been made to cover the bottoms of ships with
that metal.
To procure an electrotype copy from a page of type, we have to take an intaglio impression from the
type, which is most conveniently effected by making a plaster cast, and afterwards rendering it non-
absorbent, or we may take it in white wax; the intaglio impression must be black-leaded and placed in
the solution to receive the deposite of copper. The horizontal apparatus is much to be preferred in this
case, and great care must be taken to disperse air-bubbles. A moderately thin layer of copper would
suffice, if it were backed with solder, type, or some such analogous alloy. This process is only likely to
be useful for works that have a large circulation; and, probably, might be found to wear longer and
print better than the usual stereotype metal; but at present we have no experience on that matter;
though there is but little doubt that for these purposes electro-metallurgy will eventually be preferred.
The application of the electrotype to the various departments of engraving, is of the greatest
importance, and the new field opened in this branch alone, is very extensive. Engravings generally are
made upon copper plates, which have undergone a tedious preparation. The copper which is to be
employed for this purpose should be as pure as possible; it has first to be rolled to a certain thickness,
after which it passes into the hands of the copper-plate maker. He carefully examines the plate, and
picks out any little piece of foreign metal he may chance to perceive, and then fills up the gap by dex-
terously hammering around it, 80 that he draws the neighboring copper over the hollow. The plate is
then well hammered, and receives a rough polish by charcoal
This copper-plate is by no means pure, as it generally contains tin and other metals, which render the
engraving sometimes difficult, and the etching very uncertain. To obviate these faults we make an
electrotype plate on one of the prepared copper-plates, and as the metal of this is absolutely pure, it is
found to be far better adapted for the purposes of the engraver. This duplicate plate possesses a
similar surface to the original, and may therefore be at once used; but it is found better to hammer the
duplicate, and prepare it with charcoal, as that greatly improves it by making it more elastic; and it is
the opinion of one of the first plate-makers in this city that the hammered plate will work as well
as steel.
On one of these electrotype plates, hammered and prepared as plates ordinarily are for engraving, a
distinguished artist had various specimens of art executed. First, the plate-maker's opinion was taken of
it, and he decided that it was vastly superior to the common copper. Here we may remark, that many
persons have doubted whether the electrotype copper would bear hammering; now this plate was thus
prepared. The plate was then sent to a letter-writer, to receive a specimen of this species of engraving,
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as well as to have his opinion of it; he stated that the quality of the copper was such that much less
labor was required for the process which it had to undergo. It was then sent to an etcher, and he
found it greatly superior to ordinary copper-plates; for the nitric acid bit with the utmost uniformity, on
account of the purity of the copper. A specimen of machine-ruling, rose-engine turning, and medal-
ruling was then executed, and the opinion of all the artists concerned in the work was similar; for the
superiority of using pure copper over the ordinary copper, which is usually contaminated with other
metals and charcoal, was apparent to all.
The exact process by which these electrotype plates may be prepared, is very simple. The plain plate
on which the deposite is to take place is to have a flat band soldered on its back, in order that efficient
connection may be made with the zinc of the battery. The heat necessary to effect this drives off the
air which infilms the metal, so that if it were placed at once in the solution of sulphate of copper the
two plates would stand a very fair chance of adhering to each other. To prevent this serious evil, the
plate which has been soldered ought to be placed in a cold place for twenty-four or more hours, which
will enable it to regain a second time its film of air. Those who are not skilful in soldering metals may
simply place a wire or piece of metal in contact with the back of the plate, as that connection will
be amply sufficient. Every part of the plate which is not intended to receive the deposite, must be
covered with tallow, wax, or any other non-conducting substance.
Having thus prepared the plate, a platinized silver battery, which exposes about twice the surface of
negative metal, is to be charged with dilute sulphuric acid, consisting of about one pint of strong
sulphuric acid in two gallons of water. By using the acid thus diluted, the risk of much local action is
materially lessened, and for the same reason the acid should never be poured into the battery till it is
quite cold.
Copying engraved copper-plates-Engraved copper-plates are not more difficult to copy than plain
ones. A plate possessing the most elaborate design, the most brilliant conception, the finest execution,
the most delicate workmanship, in fact every thing calculated to render a plate valuable, can be copied
with the same readiness, the same fidelity, the same ease, as the plate without any workmanship at
all; because the deposite of new metal takes place in such a way that an exact cast is made in both
instances.
The design of all engraved copper-plates is in intaglio, or depressed below the surface, and the problem
is, to obtain a duplicate in a similar state. To effect this, a reverse of the plate must first be taken in
relief. This may be done in various ways. In the first place a relievo may be obtained in copper,
precisely in the same way as a duplicate plain plate. This is the most perfect process, and should
always be adopted for very delicate designs.
The multiplication of steel plates.-Steel plates can only be copied in a peculiar manner. They must
not be placed either in the sulphate, nitrate, or muriate of copper, as certain destruction would ensue.
I have heard of steel plates being thus destroyed, and therefore I particularly dwell on the fact to pre-
vent its repetition. The crystallized acetate of copper is not decomposed by steel, though after the
galvanic current has been passing for some time free acid is left, which is apt to attack the steel. A
steel plate, however, undergoes no change in an alkaline ammoniuret of copper, ammonio-sulphate,
or ammonio-nitrate of copper. From these salts, therefore, the copper may be thrown down upon the
steel, but I am afraid that no advantage can be taken of the fact, as the reduction of copper by these
means is attended with considerable difficulty. Under these circumstances we must have recourse to
other methods of making a relievo duplicate from a primary plate of steel. This may be done in either
lead, wax, plaster, or any other substance on which we can obtain a perfect cast, and from this a
copper-plate can be again made in the same way.
Besides these modes of making a relievo from a steel engraved plate, I have yet another plan to
propose, which is even far superior to any yet detailed, and which, on that account, must supersede
every other mode. This process of multiplication, which is so excellent, consists in first making a
reverse in silver, and lastly, a second reverse in copper, which is used at once for printing. To effect
this object the steel plate must be carefully cleaned from any adherent grease, and allowed to remain
in a cold place twenty-four hours before using it. A strong solution of argento-cyanide of potassium
must then be procured and placed in a stoneware or glass vessel. A piece of silver connected with the
platinized silver of a battery should be next placed in the solution, and the size should be about the
same as that of the steel plate. The last operation is to immerse the steel plate itself, which must not
be effected before it is connected with the zinc of the battery. The process should be continued till the
silver is sufficiently thick for removal, which operation must be performed in the usual manner. There
are, perhaps, no processes in the whole range of electro-metallurgy more easy than this; for the silver
may be obtained of excellent quality, and not the slightest adhesion will be found to exist between the
original and duplicate; even the absolute polish of a highly-burnished surface will not suffer any injury
from such a proceeding.
It is hardly necessary to mention that this process is applicable to steel dies, punches, and every
other kind of article, as no greater difficulty would ensue in conducting the operation.
The only detriment to the formation of a silver relievo, is the expense of the metal, which in large
plates would be considerable perhaps, in some cases, that might be diminished by giving a layer of
copper; otherwise we must be careful, as soon as we have formed a second reverse of copper, to remelt
our silver, and take especial care to suffer as little waste of metal as possible. The process, except in
the great value of the silver, is profitable from the equivalent of silver being high.
The multiplication of cood-cuts.-Civilized nations ought to regard the first application of wood-cuts
with peculiar veneration, as they seem to have suggested the idea of printing. At the present time,
however, wood-cuts demand especial notice, on account of the beauty of their execution; for they have
now been brought to such perfection, that in minuteness and sharpness of drawing, I have seen speci-
mens which fairly rival steel engravings. They might appear not often to require multiplication,
because it is almost impossible to wear them out; 10,000, 20,000, 50,000, nay, even 100,000 impressions
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have been taken from one wood block. Still, however, a duplicate in copper is frequently required for
various purposes. Wood-cuts are somewhat the reverse of copper-plates; for in the latter the print is
obtained from the ink left in the hollows of the plate, but in the former the design is the most elevated
part, and the impression is printed from the ridges.
For the multiplication of wood-cuts and other analogous designs for printing surface-blocks, electro-
metallurgy is useful in a variety of ways. Cuts that are used for a variety of purposes, where many
persons design a separate block to print, the type-founder usually has the design cut in wood. This is
coated at the back and edges with wax or grease, black-leaded, and immersed in the solution of
copper in the usual way, so that an intaglio copper mould is produced. This mould may be used to
make copper reverses, which are at once ready for the printer; or it may be used as a die to form
clichée casts.
In no application of electro-metallurgy is the value of the science more conspicuously shown than
in a mode of producing surfaces for printing lately patented and called Glyphography. This branch
of art forms an important feature in the general illustration of printed works, and on that account de-
mands particular consideration. The term Glyphography has been given to this invention to signify
that the original drawing itself is at once engraved, requiring no copying, and in fact scarcely any
instruments, except those with which the artist makes his design. The mode in which so extraordinary
an end is accomplished, appears very simple when it is detailed. The most essential part of the process
is to make all the surfaces for printing as flat as possible, and for this purpose a plate of copper as used
for engraving is first procured. This is blackened with the sulphuret of potassium, in order that the
draftsman may be enabled to judge of the effect which his drawing would produce, as he proceeds with
his work. This blackened plate is warmed, and then coated with a compound of burgundy-pitch, white
wax, resin, spermaceti, and sulphate of lead, previously fused together. This composition, which is
nearly white, must be uniformly spread over the plate, and the thickness should be about the one-
thirtieth of an inch. The plate is now ready for the artist, who cuts through the white composition
completely down to the blackened copper, and in fact with the exception of that precaution makes his
drawing in the usual manner. In the selection of tools the artist should be guided by the manner in
which they can completely and clearly cut out the composition; for it is important to make a clear
indentation, and not to turn aside the coating and leave a burr. A simple hook fixed in a wooden
handle, a hook filed away on one side, which most effectually cuts away the composition, or a piece of
wood tapering to a fine point, are the forms particularly recommended.
When the artist has finished his drawing, the parts of the composition which are removed leave black
lines, which have precisely the same relation to the white ground as the black lines in the subsequent
print have to the white paper.
The plate upon which the design is drawn, in the manner already sufficiently detailed, is then sent
back to the patentee to be treated differently, according as the artist desires an electro-glyphographic
cast, or a stereo-glyphographic cast from which to print. If an electro-glyphographic cast is desired,
and this is always to be preferred for very delicate and highly-finished drawings, the high lights are
built up with any non-conducting substance, in order that they may not print. Where, however, the work
is much thicker this process is not required, as the interval between the lines not being so great, the
depression between the lines need not be so deep. The plate is then placed in the metallic solution,
and an electro-cast is taken in the same way as in duplicate copper-plates, dc. As soon as this is
finished, the back is soldered and mounted upon a block of wood or to a piece of metal. The block is
at once ready for printing, and with the moderen improved system of overlaying now adopted by
wood-cut printers, the print is an exact copy of the original drawing.
All our previous operations have been conducted at the negative pole of the battery; but at the pos-
itive pole certain effects take place which may be taken advantage of in the arts. Let us call to
mind the fact, that gold, silver, and all metals with a greater affinity for oxygen, are dissolved when
made the positive pole of a cell charged with a solution of the same metal. Now the relative distance
which is maintained between the positive and negative poles affects the degree of solution which takes
place. This property may be easily shown by attaching a wire by one of its ends to the silver of the
battery, and placing the other in a solution of sulphate of copper, in the bottom of which a piece of cop-
per connected with the zinc of the battery is immersed. After a short time, the wire will begin visibly
to be dissolved, and the part nearest the negative metal will be affected; this will go on till the wire is
dissolved, in such a manner that the part nearest the negative metal will diminish to the sharpest point.
and the different amount of action will produce a perfect taper.
Although this property is of no value in its application, yet I have introduced it to show the facility
with which the copper in every place is dissolved exactly in proportion to the electricity passing and
this is likely to be extremely valuable for engravers in their etchings. The term etching, is given to
those engravings where the lines are not cut by any instrument, but are dissolved out by an acid. In
order to make an etching, a copper-plate is first to be prepared by covering it with a substance which
protects it from the action of the acid in which it has to be immersed. The substance used for this
purpose is composed of asphalte and wax in equal proportions, combined with a fourth part of both
black pitch and burgundy-pitch. This mixture is placed in a piece of silk, and rubbed over the copper-
plate, which is kept at a moderate heat, by holding it over a lamp or chafing-dish. This operation is
technically called laying a ground; this at first is colorless, but it is afterwards blackened by holding it
over the flame of a candle, and depressing it till a copious supply of smoke covers the surface.
The engraver, with an instrument like a needle, called an etching-point, executes his drawing, and in
so doing removes the ground, and exposes a clean surface of metallic copper. The plate is then placed
in a dish, and dilute nitric acid poured upon it, till the copper is dissolved out from the exposed lines to
a sufficient depth. The plate is not allowed to remain in the acid a sufficient length of time to bite
deeply, as this would cause the engraving to be of one degree of blackness; but after it has been in the
acid a short time, those parts which are required to be of a light shade are stopped out, that is, they
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are covered with brunswick-black, or a coat of varnish capable of resisting the action of the acid. The
plate is then replaced in the dilute acid after a time it is again removed, and a further portion is stopped
out and these operations are repeated as many times as there are differences of shade required in the
engraving. The degree of perfection that the professed engraver obtains by practice is truly extraor-
dinary, considering the uncertainty which must attend the operation; for the action of nitric acid is not
subject to any regular laws, and moreover is never alike over all parts of the same plate. This is ow-
ing to the copper-plate itself being never pure; but always containing tin, dispersed here and there
throughout its texture, which resists the action of the acid. After a splendid plate is bitten in, some
portions are sometimes left which cannot be acted upon by the nitric acid, but absolutely require the
graver to bring up the fine lines.
No engraver that I have conversed with, can explain the cause of these faults in their work, but to
the chemist they are perfectly intelligible the nitric acid attacks the copper, forming a soluble nitrate
of that metal which is dissolved in the fluid; but the action of nitric acid on tin is altogether different,
for it converts the metal into a peroxide, which, being insoluble, protects the copper from the acid. The
engravers have always noticed this white powder, (the peroxide of tin,) so fatal to the success of their
operations.
Etching by galvanism is a far more certain operation than the foregoing, because it can be reduced
to known principles. In this case, the plate to be bitten in has the device first drawn upon the same
ground that is used in the ordinary process; the back and edges of the plate are then coated with wax,
and it is to be connected by means of a wire with the silver plate of one or two of my batteries.
The piece of copper to form the negative pole should then be connected to the zinc, when both the
copper-plate and the piece of copper are to be placed in a solution of sulphate of copper. Immediately
copper will be reduced from the solution on the negative plate, and copper from the etching-plate will
be dissolved to keep up the strength of the solution.
Whatever is favorable to the increase of electricity, causes the copper to be more quickly acted upon,
and whatever diminishes the galvanic current, retards the solution of the metal; the nearer the etching
plate forming the positive pole, and the piece of copper forming the negative are approximated, the
more rapid will be the action. In the same way, the intensity of the battery also affects the rate at
which the plate is bitten in. The negative plate of copper, however, should not exceed in size the cop-
per-plate on which the etching is executed, or else there is a risk of some of the lines being more deeply
bitten in; and in like manner, if any considerable part of the plate has a great deficiency of lines com-
pared with other parts, that part must be stopped out rather before the other, to ensure a uniformity of
depth, or else the negative copper opposite this part must be bent in such a way as to increase the dis-
tance.
The advantages of galvanism for etching, are, the absence of poisonous nitrous fumes, which are
evolved in the ordinary process; the greater uniformity of action which takes place than when acids
-are used; and the rapidity of biting, which may be regulated to the greatest nicety. The lines may be
made of any depth, and are sharper and cleaner than when acid is used; and lastly, no bubbles are
evolved, which the engraver well knows are apt to tear up the ground, or to cause unequal action.
The exact quantity of copper dissolved from the plate, can be ascertained by weighing the metal
reduced on the sheet of copper which forms the negative pole, or by measuring the quantity of hydro-
gen evolved from the silver plate of one of the platinized silver batteries for thirty-two grains of cop-
per will be dissolved for every forty-eight cubic inches of gas evolved.
Etching by getbvanism can be executed with any desired degree of rapidity, according to the series of
batteries to which the plate is connected; but I believe that the practical man will find that the action
should neither!b too slow nor too quick, and perhaps two or three batteries, arranged as a series, will
be found best adapted, though a single cell would suffice.
Galvanism-would be valuable to the engraver for executing gradations of shade, such as, for instance,
the effect of a strong light illuminating a whole room. The most simple manner in which this can be
shown, is to take a copper-plate and draw a number of lines on the ground with a ruling-machine.
The plate, after having its back and edges coated with any non-conducting substance, should be then
connected with the silver of the battery, and copper wire. These two should be then arranged in the
solution of sulphate of copper, that at one end they nearly touch, while at the other they are widely
apart. By this position, the greatest quantity of electricity would pass at that part of the plate where
it is nearly in contact with the negative pole, whilst the least would pass at the opposite extremity.
The action on the etched plate being exactly in proportion to the quantity of electricity passing, is un-
equal over the whole length of the plate, being greater where the metals are nearest, and gradually
diminishing to the other end. This is the most perfect mode by which it is possible to obtain a grada-
tion of shade. Many variations in the arrangements might be made by using, as a negative plate, a
wire or a rod of copper, placed over the centre of a prepared plate; for then a perfect gradation would
be obtained, extending in all directions from the dark centre. In the same way, two or more radiating
shades may be obtained, by using two or more negative wires. An insensible gradation might be made
from the darkest shade at the external edge of the plate, to the lightest point at its centre, by cutting
out a hole in the negative piece of copper, opposite to the part where the transition into light is re-
quired.
The professed engraver who once practically masters the galvanic method of etching by the theoreti-
cal principles which I have here detailed, is sure to obtain great results. He could execute with ease
the most extraordinary transition of light into darkness with fidelity, and with the utmost certainty.
However, I trust that the value of electric etching will not be confined to the artist; for, by removing
the disagrecable consequences attending the use of nitric acid in the present mode of etching, more per-
sons may be induced to enter into it, and, by this means, numbers studying the sciences will be enabled
to exccute an etching of those objects which are curious and rare, to send to their brethren who are
stu lying the same subject. Those travelling in foreign countries, or in picturesque situations, might
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transmit to their distant friends an idea of the sublimity and grandeur of the scenery which they are
enjoying, or of the appearance of the towns and villages through which they are passing. In fact there
is not a person who might not be benefited by receiving etchings from others, and who might not, in
return, circulate engravings of those objects which he may see. Pictorial representations are avowedly
better than any verbal descriptions, 80 that there is ample scope for any one to exercise his talents use-
fully; and certainly many cannot be aware that etchings are not more difficult to execute than common
pencil drawings. The process is as suitable for ladies to practise in their drawing-rooms, as are any of
their usual amusements; the operation being attended with as little trouble. It is necessary at first to
have the plate prepared, or have a ground laid, (which might be done by a workman,) and at the con-
clusion of the drawing it has to be bitten in. The objection to this, hitherto, has been the disagreenble
properties of the acid, as it is likely to spoil clothes or injure furniture; but now that these objections
are removed, I trust that numbers will enter into this amusing and useful branch of art.
Galvanic etching has lately extended to the etching of Daguerreotype plates. The silver plate is
arranged as the positive pole in a trough, by connecting it to the negative plate of a battery. The sil-
ver plate is about the same size as the Daguerreotype; but I believe that we should be able to bite
much deeper by following the improvements in galvanic etching. It is stated that these etchings when
printed showed extraordinary minuteness of detail.
There are purposes besides electro-metallurgy for which the galvanic force is applicable to the wants
of mankind, and of the most conspicuous of these is the mode of blasting in mines and under water now
adopted.
The barrel, Fig. 1289, in which the pow-
1989.
der is placed has a hole bored in it, so that
it may admit a copper tube t. This cop-
per tube has a plate soldered to it at the
upper part by which it may be fastened
by copper nails to the cask a plug H is
fixed in the tube, through which two cop-
per wires are inserted, and round the end
H
of the wires is wound a fine piece of
TT
platinum wire p, so that but a single fila-
ment extends from wire to wire; the rest
of the tube is filled with fine powder,
and a piece of cork c is placed on the
other end. This copper tube is then
carefully secured water-tight by smearing
pitch round the copper. For securing the
tube and wires in their place, the ends of the two copper wires are bent and nailed to the tub. The
next thing is to fill the tub with blasting-powder by another hole, and then secure the aperture wa-
ter-tight with a wooden plug, which is afterwards smeared over with pitch. The cask is then
lowered to the bottom of the vessel, and placed in the situation where it is destined to act. A rope,
previously made by procuring two wires first covered with cotton and varnished, and twisting them
with the texture of which the rope is made, is then lowered to the bottom of the sea, and the ends of
the two wires communicating with the tube are tightly lashed to the two wires in the rope. All these
things being ready, the ends of two wires at the other extremity of the rope are connected with the
two extremities of a small compound platinized silver battery, when, immediately on contact being
made, the explosion takes place.
ELECTRO-MOTIVE ENGINE Description of the Electro-Motive Engine-constructed on the
supposed principle of muscular power. At a meeting of the Medico-Chirurgical Society of Aberdeen,
July 6, 1848, W. Fraser, Esq., read a paper on the subject of the Electro-Motive power, of which we
give the following extracts:
" Having several years ago had an opportunity of seeing a number of electro-motive machines of
various constructions, I was much struck by observing the extreme weakness of the power rendered
available for practical purposes by the different mechanical arrangements employed, compared with the
tremendous force actually exerted, under certain circumstances, by the moving power made use of. An
electro-magnet, which would, within its proper sphere of power, attract to itself, and retain suspended,
a weight of many tons, could not be made to perform the twentieth part of the labor of one horse.
" I shall not occupy your time by describing those arrangements, but come at once to the description
of one upon an entirely new principle, which 1 have carried into effect with the happiest result, and of
which the idea was suggested by the mode in which the muscular force appears to be exerted in our
own body.
" It has for some time been a current belief in physiology, that the contraction of muscles is produced
by the mutual attraction of minute cells, arranged in parallel lines, of which the ultimate fibrils of the
muscular tissue consist. The stimulus that excites this attraction, is the vital electricity, transmitted by
the nerves, and brought to bear upon the muscular globules by means of the ultimate nervous filaments,
which interlace among them, and form a network, 80 as to complete the circle or current of nervous in-
fluence of which the prime motor is the brain. The aggregate of these minute movements gives the
extent of contraction of the entire muscle; the combined force of these molecular attractions, its full
power or strength.
The following extracts and figures, from Dr. Carpenter's Manual of Physiology,' will place the sub-
ject more clearly before us:-
When the fibrillæ are separately examined under a high magnifying power, they are seen to pre-
sent a cylindrical or slightly beaded form, and to be made up of a linear aggregation of distinct cells.
We observe the same alternation of light and dark spaces as when the fibrillæ are united into fibres or
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ELECTRO-MOTIVE ENGINE.
into small bundles: but it may be distinctly seen, that each light space is divided by a transverse line,
and that there is a pellucid border at the sides of the dark spaces, as well as between their contiguous
extremities.
This pellucid border seems to be the cell-wall; the dark space enclosed by it, (which is usually
bright in the centre,) being the cavity of the cell, which is usually filled with a highly refracting sub-
stance. When the fibril is in a state of relaxation as seen at a, Fig. 1297, the diameter of the cells is
greatest in the longitudinal direction ; but when it is contracted, the fibril increases in diameter AS it
diminishes in length, 80 that the transverse diameter of each cell becomes equal to the longitudinal
diameter, as seen at b, Fig. 1297, or even exceeds it.
1292.
1291.
1290.
1293.
The diameter of the ultimate fibrillæ will, of course, be subject to variations in accordance with the
contracted or relaxed condition; but it seems to be otherwise tolerably uniform in different animals,
being, for the most part, about 1-10000th of an inch. The average distance of the striæ, too, is nearly
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uniform-about 1-10000th of an inch in different animals, though considerable variations present them-
selves in every individual, and in different parts of the same muscle.'
" On the subject of the arrangement of the nerves and tendons in connection with muscles, the same
authority says, The muscles of animal life are, of all animal tissues except the skin, the most copiously
supplied with nerves. These, like the blood-vessels, lie on the outside of the myolemma of each fibre,
and their influence must, consequently, be exerted through it. The arrangement of these nerves is
shown in Fig. 1296. Their ultimate fibres or tubes cannot be
said to terminate anywhere in the muscular substance; for,
1296.
after issuing from the trunks, they form a series of loops, which
either return to the same trunk or join an adjacent one. The
occasional appearance of the termination of a nervous fibril, is
caused by its dipping down between the muscular fibres, to
pass between another stratum.
Every muscular fibre, of the striated kind at least, is at-
tached at its extremities to fibrous tissue, through the medium
of which it exerts its contractile power on the bone or other
substance which it is destined to move. Thus the whole mus-
cle is penetrated by minute fasciculi of tendinous fibres, and
these collect at its extremities into a tendon.'
" Of the anatomical arrangement now described, the electro-
motive machine here presented is as close an imitation as
possible: it consists of a number of electro-magnets opposed
endwise to one another, arranged in parallel lines, and con-
nected together by fastenings in such a way that, when made to act simultaneously, their united force
can be brought to bear upon one point."
The annexed figures will give an idea of the apparatus, both in a state of repose and of action.
Fig. 1290 represents a series of eight rectangular prisms of soft iron, one and one-eighth of an inch
long, by a quarter of an inch square, placed endwise, at the distance of one-twelfth of an inch from one
another. Fig. 1291 shows the same in close contact. Figs. 1292 and 1293 represent the prisms in the
same relative position, but armed with a continuous covered copper wire, and connected together in
such a manner as to admit of free motion within a limited extent. Each prism has covered wire, about
one-twentieth of an inch thick, wrapped around it closely and regularly, in three layers, and, before
being carried to the next prism or magnet, the wire is extended out for about an inch and a half at
right angles to the prism, and bent back again at an acute angle, by which means the resistance it offers
to the motion of the magnets is almost entirely overcome.
The prisms or magnets, with their opposite poles to each other, are connected together by ligaments
of catgut, the length of which can be 80 graduated, by twisting them by means of a small pin, (which
can be fixed by having its end inserted among the wire,) that any distance that may be necessary can
be assigned as the limit of motion to the magnets. It is proper to mention that the prisms are all
bound together by two bands of vulcanized india-rubber, in close contact with their opposite sides, and
sufficiently on the stretch to overcome entirely the weight with which, when hanging perpendicularly,
one part of the apparatus would bear upon the other.
1295.
1294.
The advantage of the arrangement now described is, that as the same current of galvanısm is equally
efficient in rendering many prisms magnetic as one, and the motions produced by the magnetic influence
are, by the way in which the prisms in the apparatus are connected together, communicated from the
one to the other, and all accumulated or brought to bear at the end of the series, the amount of power
gained is just the attractive power of one prism multiplied by the number in the series, deducting, of
course, the resistance to be overcome by removing the additional number of magnets.* *
# The apparatus above described, which weighs five and a half ounces, with the aid of a moderate battery lifts a pound
and a half a distance of nearly half an inch. Its action is almost instantaneous; and the shock with which it becomes rigid
or relaxed, as the stimulus is applied or withdrawn, reminds one very forcibly of the spasmodic action of a muscle.
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ELECTRO-MAGNETIC ORE-SEPARATOR.
Supposing one electro-magnet to be capable of raising three pounds one-twelfth of an inch by com-
bining 96 of them into one chain or series, in the way shown in the model, there would be attained a
power of raising three pounds a distance of 96-12 of an inch, or 8 inches; but allowing the additional
magnets and their appendages to weigh one pound and to be provided with no counterbalancing arrange-
ment, then it is evident that the actual power attained would be only that of raising two pounds a
height of 8 inches. But by combining 100 such columns, each containing 96 magnets, there would be
attained a power of raising 200 pounds 8 inches, or 100 pounds 16 inches, or 50 pounds 32 inches, &c.,
according to the manner in which the combination was made.
Figs. 1294 and 1295 show how the chains of magnets might be combined into a compound machine;
one end of them being attached to the fixed beam a, near which the battery is placed, their other
extremities being fixed to the moveable beam b, from which any motion required could be easily taken.
In Fig. 1294 the magnets are in a relaxed state, their connection with the battery being broken; while
in Fig. 1295 they are in a state of contraction, the circuit of wire which connects them with the battery
being complete.
By combining a number of such frames together, all connected by the same wire, and by 1297
augmenting the strength of the battery, any degree of power might be obtained, and, as in
a
the steam-engine, the apparatus might be easily made self-governing in its action, by having
a small cup of mercury with which one of the wires was connected, placed, say at c, Fig. 1294;
the other end of the wire could be made alternately to dip into it and emerge from it by
means of a pendulum, so as to break and restore the connection, and thus keep the machine
going with any degree of frequency that might be required.
Upon the whole, it is evident that the power of such an apparatus would depend upon the
perfection of its mechanism. And as the force of the attraction of electro-magnets increases
prodigiously as their distance diminishes, (see Robert Murphy's Elementary Principles of the
Theory of Electricity,) it follows that the smaller and more numerous the component magnets
of the machine could be made, the greater would be the power attained. But in this respect,
it is not to be expected that human ingenuity could ever be able to reach, by many hundred,
we might say thousand, degrees, the minuteness of the muscular tissue. Yet even if the motive
power attained were only a five-hundredth part of that which muscle can be made to exert, in
proportion to the weight of the apparatus, this would be a very great advance upon the
results that have hitherto been arrived at in this department.
Though, undoubtedly, it will be long before electricity be brought even to compete with
steam as a source of mechanical power, yet such a result need not be looked upon as
chimerical
Another necessary step towards this consummation, besides the perfecting of the mechan-
ical arrangement, would be the discovery of a cheap source of galvanism one whose price
would not exceed that of the fuel employed in the production of steam. But that the very
same source from which steam is obtained may be made available for the generation of elec-
tricity, is proved by recent experiments; though whether in a form suitable as a source of electro-motive
power, yet remains to be ascertained.
ELECTRO-MAGNETIC ORE-SEPARATOR: Cook's. The machine represented in Figs. 1298,
1299, and 1300, was invented by Ransom Cook, Esq., of Clinton county, N. Y, and employed for the
separation of the magnetic ore. The principle of this invention consists in charging successively, by a
battery, different rows of magnets on a revolving cylinder, 80 that the magnets shall lift magnetic ore
1298.
N
from an endless web as it passes under the cylinder; and SO also that when the ore is lifted up a short
distance the electric connection shall be broken with the magnets, and the ore then drop from them into
the trough, and be discharged into a proper receptacle.
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Fig. 1299 is a side elevation of the machine ; Fig. 1298, a top plan; and Fig. 1300, a sectional view.
A A is the frame. B is a pulley by which the cam-shaft C is revolved. This shaft, by the cam C,
shakes the hopper F so as to spread the ore evenly across the endless web or carrying apron H. This
is done by having a hook-rod K that catches the upper edge of C, and is made, from the shape of the
cam, to traverse across the web, and spread the ore equally on the web. D is the revolving magnet
cylinder, driven by band and pulleys ONP. L is the trough into which the ore is discharged from the
cylinder. X X are mercury troughs, the one charged positively and the other negatively from the
battery, by the wires MM. The magnets are fixed on the revolving cylinder, and wound round with
copper wire, the one positive and the other negative. These wires are carried from one magnet to
another across the row, and brought out at the axle of the cylinder, forming a circular fan E, 80 that as
the cylinder revolves, and the wires dip into and rise from the charged mercury troughs, the rows of
magnets are charged and broken alternately, to lift the ore from the dross and deposite it in the receiving
troughs.
D
1299.
M
L
H
B
H
The magnetic cylinder revolves to meet the ore as it comes forward on the web, and in the same
direction. TT are the magnets. M represents the wires from the battery. The large cylinder is
revolved by a band from the other side, passing over a pulley on the shaft of D, the magnetic cylinder.
The cylinder is made of wood, a non-conductor; and to insulate the wires perfectly, the axle of the
cylinder is boxed with wood, and wires turned up on the outside of it.
1200.
E
E
D
Ln
TI
T
Fig. 1300 shows the manner in which the magnets are arranged on the cylinder. D is the cylinder;
TT the magnets; E the current wires; and X the trough of quicksilver. The cylinder is about 30
inches in diameter, and the magnets are about I of an inch thick, with four polar points. There is a
space of about 1 of an inch between each of the magnets, and a large cylinder has had thirty rows of
ten magnets each. It will be observed that the wires are alternately wound in the direction of the
polar currents. One wire is now represented as dipping in the mercury; but one-fourth of all the
magnets are charged at the same time, as that number touch the mercury on the under side of the
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ELEVATORS.
cylinder; but the magnets are charged and discharged successively in rows. The ore is carried forward
on the endless apron; and the magnet cylinder, by revolving in the same direction as the apron, lifts
the ore, while the dross is discharged from the apron while passing over the roller.
This machine has been in operation at Plattsburgh for some time, where it is stated to have exceeded
the most sanguine expectations. When ore is associated with hornblende no other process of separation
can, it appears, compare with this.
1301.
a
1302.
R
a
O
1303.
1306.
0
SCALE.-8 feet=1 inch.
&
1304.
I
&
1305.
CL
ELEVATORS. The general term Elevator includes gins, windlasses, cranes, &c.; but since these
are described under their separate heads, in this article are comprehended only those smaller machines
employed to raise materials in mines, furnaces, factories, and corn mills.
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Figs. 1301 to 1303, a vertical elevator, moved by hand.
Figs. 1304 to 1306, a similar one, driven by steam or water-power.
Figs. 1307 to 1316, a single elevator working on an incline with an endless chain.
Figs. 1317 to 1321, a similar one, with a rope.
Figs. 1322 to 1325, a similar one, but double.
01
a
R
1307.
B
1309.
SCALE.-9 feet=1 inch.
1315.
1316.
A
A
1314.
1308.
Hh
DO
0
DO
9
0
00
1310.
1311.
DO
A
1312.
1313.
Figs. 1326 to 1328, an elevator moved by condensed air or a pneumatic engine.
Figs 1329 to 1333, elevators for corn-mills.
Figs. 1334 to 1337, elevators for factories.
Figs. 1338 and 1339, elevators for general purposes.
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ELEVATORS.
A vertical Elevator, moved by hand.-Fig. 1301 is a side elevation; Fig. 1302, a front elevation; Fig
1303 a section on the line a b. The weight to be raised is placed on the platform a of the frame a e.
which, moving between the posts c 6, is retained in position by grooves in a and e, as shown clearly in
the section, Fig. 1303. The platform is raised by the winding of the chains or ropes attached to the
frame at f, on the barrel h, which, if the weight is trifling, is turned by a winch on its own shaft, but
more commonly an extra shaft i, geer l, and pinion k, are employed with the winch m ; two ratchet-
wheels q r and catches 8 and t hold the platform in any desired position. A counterpoise P is attached
by the rope o, passing over the pulley n to the barrel h.
A vertical Elevator, driven by steam or water power, used in the iron-works of Belgium.-Fig. 1304 is
a front elevation; Fig. 1305, a side elevation; Fig. 1306, a plan of the lower part. The parts are as
follows: The standards c and d support a lower shaft a and upper b, to each end of which are fixed the
iron wheels e e, of about 71 feet diameter and 7 inches wide, cast with projections ff, adapted to the links
of the endless chains gg; at distances of about 5 feet the two chains are connected by iron rods h h h,
from which depend the platforms k, on which are placed the loads to be raised or lowered. These
weights can be put on or taken off while the machine is in motion, and if from neglect the load is not
removed, the only result is that it continues to ascend and descend with the revolutions of the
wheels c e. Motion is communicated through the shaft p, the pinion m, and the geer z, fixed to the
shaft a: q is a slide coupling; 00, standards of the shafts p and n: and и a pit or span necessary
below a, for the passage of the platforms.
An Elevator working on an incline, with an endless chain, used at some of the blast-furnaces of
Belgium.-Fig. 1307 is the side elevation; Fig. 1308, the rear elevation; Fig. 1309, the plan. A A is
the bottom, and BB the top platform; CC the railway, inclined at an angle of about 30°, and supported
by the frame DD. The wagons are drawn up by the endless chain a a a, resting loosely in the wheels
bbcc, to which last motion is communicated through the geers e and f, and the pulley h, over which
passes a band i from the prime mover. Figs. 1310 and 1311, represent two views of a portion of the
wheel cc; Figs. 1312 and 1313, of the wheel bb; Fig. 1314, of the chain. It will be seen that there
is but one row of projections kk on the rim of the wheel c, fitting the openings m of the links of the
chain, while on b the row is double, and is adapted to the spaces n n of the chain.
The loaded wagon being brought to the bottom of the incline, the hind axle is caught by one of the
hooks g, (which are about 9 feet apart,) and is drawn up. At the top the wagon is received on a small
descending railway, inclined at an angle of about 5°, and whose summit is sufficiently above the plat-
form BB, that gravity alone will carry the wagon to its place of unloading. The emptied wagons are
placed on a side track $ s, and are lowered by means of a rope attached to the windlass tt, Figs
1308 and 1309.
Along the railway 00, and at a distance of from 5 to 6 feet, are placed the moveable catches or bell-
levers и, which, in case of the breakage of the chain, will catch the hind axle and stop the descent of
the wagon.
The wagons used in Belgium are composed of cast and wrought iron, and the materials for supplying
the furnace are first put in plate-iron vessels, (holding from 30 to 40 pounds, and of the form repre-
sented in Figs. 1315 and 1316,) and then placed in the wagons, which contain from 12 to 18 of them.
An Elevator working on an incline with a pulley-rope.-In blast-furnaces, where only charcoal is used,
the elevator, represented in Figs. 1317 to 1321, is frequently employed. Fig. 1317 is a side view Fig.
1318, a plan; Fig. 1319, a section on the line B; and Figs. 1320 and 1321 are details.
The principal axis k1, Fig. 1320, is at k, where the drum I is cylindrical, and at k, squared. On this
part is placed the moveable wheel m, with the knobs n n, which are inserted into corresponding holes
of the drum 1, whenever this latter is to follow the movement of the axis k k1. In the periphery of the
wheel is carved a groove, into which fits the quadrant o, Figs. 1317 and 1320, wound like the worm of
a screw, and fixed to the shaft p. To this shaft is also fixed the disk q, Figs. 1317, 1320, and 1321, on
whose periphery is placed the bar rr, which is joined to it by the counter-chains 8 and t, Fig. 1321, in
such manner that the wheel, together with the shaft p and quadrant o, is alternately turned to the left and
to the right, according as the bar is pushed backwards or forwards. By this the wheel m is either moved
on or off the drum 1, and consequently the latter is brought in or out of connection with the axis k k₁.
A double Elevator working on an incline with pulley-ropes.-At blast-furnaces, where the smelting of
the ore is effected by means of coke, and large quantities of iron, stone, fuel, and other supplies are to
be conveyed up to heights of 30 or 50 feet, several of these elevators are applied. On the inclined
plane, forming an angle of 30 or 40°, are two railways, parallel to each other; the one serving for the
ascent of the charged wagon, and the other for the descent of the empty one. An elevator of this kind
is represented in Figs. 1322, 1323, 1324. and 1325. Fig. 1322 is a side elevation; Fig. 1323, a plan;
Fig. 1324, a front elevation; and Fig. 1325 represents the principal axis with its two drums and levers
for moving out and in the clutches.
An Elevator moved by condensed air or pneumatic engine.-At the iron-works of Chatlinot, near
Charleroi, in Belgium, an elevator of this description, and about 50 feet in height, was constructed in
1839, for three blast-furnaces, where the smelting of the ore is effected by means of coke. The con-
densed air, required as motive power, was derived from the great wind-reservoir of the blast apparatus,
the air here being condensed at the rate of 4 pounds pressure on the square inch. This elevator is
represented on page 460, where Fig. 1326 is a side elevation; Fig. 1327, a front elevation; and Fig.
1328, a horizontal section of a part immediately above the cylinder.
The frame a a, Figs. 1326 and 1327, is composed of upright standards and cross-bars, whose joints are,
for the sake of durability, covered with iron bands. The nine vertical beams bbb form in the plan four
equal squares, Fig. 1328. They rest on cast-iron pedestals cc, Fig. 1326 and 1327, and into whose holes
they are firmly fixed by means of wooden wedges. In two of the squares, by the side of each other, the
iron ore and other materials are drawn up in vessels or tubs A A, one of which is represented in Fig.
1328 The vessels are provided with two cast-iron crosses d and e, joined by the wrought iron bars
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ELEVATORS.
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ff. The cross-arms form diagonals of the squares, and are at their ends provided with rollers gggg,
grooved at their periphery, to fit the rectangular rails hhhh, on which they run up and down from the
bottom to the top of the elevator. The vessels containing the ore, etc., are placed on the iron plate ii
a
8
1319.
1318.
TN
8
0CK
II
n
Or
1321.
P
B
1317.
1320.
B
-
#
b
z
1325.
F
1324.
SCALE.-9 feet=1 inch.
1323.
:
1322.
6 701
w
IZ
NSE
resting on the lower cross. The equare marked kk, Fig. 1328, signifies the upper face of a pedestal. To
each of the frames is fixed the chains il, II. The other ends of the chains pass round the cast-iron wheel
m m and are fastened. The wheels are fixed on the shaft nn, to the middle of which a third wheel o
is attached. of far smaller diameter than that of the other ones, and to whose periphery is fixed the
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460
ELEVATORS.
chain pp, fastened at its lower end to the joint-head q of the piston-rod r. The piston P moves up and
down in the air-cylinder 88, which is about 10 feet high, 2 feet in the diameter, and open below. The
piston-rod is packed as in a steam-engine. At the side of the cylinder is the valve-box и, Fig. 1827,
which receives the condensed air from the reservoir of the blast apparatus through the pipe vv, and
from which again it can be let into the cylinder $8, by means of the valve w, Fig. 1327. The valve w
m
1326.
A
1327.
&
I
my
1328.
D
m
SCALE.-9 feet=1 inch.
0
@
1332
OR
I
Y
1329.
to
1331.
D
1330.
Y
F
a
*
B
a
1333.
&
is hollow, to permit the escape of the condensed air (after it has pressed down the piston to the ex-
tremity of the cylinder) through the aperture x. As soon as the valve w is moved out of its position,
as shown in Fig. 1327. downwards, (which is effected by the combined contrivance of the bar a, the
shaft B. end the lever y,) the condensed air acts on the piston t and presses it down. The effect of this
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ELEVATORS.
461
is, that the vessels A A are drawn up simultaneously with a velocity surpassing the movement of the
piston in proportion to the difference in diameter between the wheels m m and the wheel o.
As soon as the vessels are lowered again, the slide w is drawn upward; and as the condensed air
filling the cylinder, escapes through the aperture x, the vessels A A sink down by their own weight,
which surpasses that of the counterbalance P. The piston t is at the same time drawn up to the upper
part of the cylinder.
Elevators in corn-mills, etc.-Elevators of this kind are very frequently used in corn-mills and grana-
ries for the purpose of raising corn or flour from one loft to another. Elevators for corn are in general
of larger size than those used for raising flour, although both are constructed and arranged on the same
system.
An elevator of this kind is represented on page 460, where Fig. 1329 is a side elevation, Fig. 1330
a front elevation, and Fig. 1331 a section of its lower part, (from the line A B, in Fig. 1329, downwards.)
Around the wheels a a is strained the band bbbb, to which are fastened or riveted the vessels c c, of
tinned sheet-iron. Motion-is generally communicated to the upper wheel by bands from some driving-
shaft. Each of the two wheels is enclosed by a wooden case, the lower one by the case dd, and the
upper disk by the case e. The interstices or channels ff and gg are so arranged, that in the former
the band with its vessels has but little play, while in the latter more space is given to prevent any
collision with the vessels cc, which otherwise might happen on account of the inclined position of the
elevator.
1335.
OC
@
P
a
MN
NM
1334.
9
N
DD
in
k
The corn or flour pours into the lower case by the channel h, and the influx can be regulated, or, if
required, entirely stopped, by the shutter or slide i. In the rear of the same case is the shutter k, for
the clearing of the case and removal of obstructions.
At the bottom of the upper case is the aperture l, into which is thrown the grain or flour from the
vessels cc, as they overturn on the upper wheel. From I the corn or flour is distributed by the trough m,
turning on the bolt n, or is in some other way removed to its place of destination. See CORN ELEVATOR.
Elevators in factories for removing manufuctured and other goods from one room to another.-An
elevator of this kind is represented above, where Fig. 1334 is a plan, Fig. 1335 a side elevation of a
section towards the middle, Fig. 1336 a transverse section, and Fig. 1337 a side elevation, showing the
mechanism of the prime movers.
In a square space passing through all the stories of the factory, the frame a a, Figs. 1334 and 1335,
moves up and down, of about 5 feet square between two beams bb placed alongside of each other. It
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ELEVATORS.
is driven by the same power that drives the factory. The frame is fastened to two ropes or bands c
and c₁, passing over the cast-iron wheel dd. To the other end of the rope c₁ is fastened a counterpoise
of the frame, or of the charge to be raised. On the shaft of the wheel d d is fastened the spur-wheel
e e, into which the spring-wheel f plays, Fig. 1334, on the opposite end of whose shaft is the diagonal
wheel g. Into this latter geer, simultaneously, the two smaller diagonal wheels h and i of the axis k k,
to which the wheel h is firmly fixed, while the wheel i is moveable on it. On the latter wheel is
screwed the cast-iron roller l, by the side of which are two other ones of the same size, m and n, the
former being moveable and the latter fixed on the common shaft kk. The band 00, Fig. 1336, con-
nected with the motive power, passes round one of these three .wheels. Suppose it be the wheel n, the
shaft k k; together with the wheel h, is revolving in the same direction as the band moves round. Con-
sequently the shaft of the wheels g and f, and at the same time the wheel dd rotating by the action
of the wheel h, the frame a a is raised, while the wheel i is by the wheel g turned round, and rotates
freely on the axis h k, in a direction the reverse of that of the band. If, on the other hand, the band 00
is removed from the disk n to l, by which the wheel i takes into the wheel g, while the wheel h is now
kept out of action, the frame a a is moving downwards. Finally, if the band be placed round the
moveable wheel m, the elevator is in the state of rest; this wheel then revolves on the axis kk, without
exercising any action.
1336.
1337.
1.
s
a
1338.
1339.
B
b
I
e
For the purpose of removing the band from one of the three wheels to another, and to regulate the
different movements in the described manner, the following arrangement is made. The beam pp sup-
ports the bearings of the shaft q, (parallel to that worked with gf,) on which is fixed the wheel r. An
endless rope st, Fig. 1337, stretching from the top to the bottom of the building, passes round this
wheel, and can everywhere easily be seized by the workmen. Now, according as the part 8 or the
part t of the rope is pulled, the disk r and the axis q are turning either to the right or to the left, and by
this and the handle v the sliding-bar и is pushed either onwards or backwards. This bar being fastened
to the band 00, by means of a fork or handle, the band is removed to one of the three disks 1, m, and n.
The distances between the two guides 20 w of the sliding-bar и, are exactly adjusted to these shiftings of
the band 00.
For stopping the movement of the frame a a whenever required, a contrivance is made, consisting of
the wheel x, Figs. 1335 and 1337, on whose periphery is laid the band y of strong sheet-iron. This band
is fixed at z, and with the other end fastened at a, to the lever ß, resting on the heart-shaped wheel γ,
which is fastened on the axis q. Now, as soon as the band 00 is placed round the wheel l or n, the
band y is lifted, and together with it the lever ß. But as soon as the band o o is removed to the wheel
m, the lever lowers again, resting with its roller in the concavity of the disk γ, Fig. 1335.
Elevators for general purposes.-In factories, for the purpose of winding or letting down heavy loads,
an elevator is frequently made use of, as represented in Figs. 1338 and 1339.
The frame a a is fixed to the timber-work of the mill, and supports a shaft with the drum bb, and the
cast-iron geer cc, into which plays the endless screw d, whose shaft ff is at both ends provided with
a winch e e. To the drum is fastened and coiled round the rope g, by means of which the load is raised
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ELEVATOR.
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up. As soon as the drum is put in motion by means of the winches, the load is either wound up or
lowered. The ring h pressing against the socket i, serves to keep the screw or worm d in geer with the
tooth-wheel c c. When the load has arrived at its place of destination, the shaft ff is pushed onwards
until the ring k presses against the socket 1. The rope g can then easily be wound off from the drum.
ELEVATOR, for raising bricks, mor-
tar, and any other materials employed in
building, and adapted to the unloading
1340.
of ships and warehousing of goods. In-
vented by M. Spurgiu. Fig. 1340.
Description of machine.-The main
B
part of the machine A, consisting of the
geering to set the machine in motion,
rests upon the ground. The second part
is a trestle, which may be placed upon
the scaffolding of the bricklayers, as at
F
F; in the upper part of this trestle is an
indented wheel B, which corresponds
perpendicularly with a similar wheel,
attached to the principal body of the
machine, resting on the ground. Pass-
ing round these two wheels is an end-
less iron chain, which is put in motion
by one or several men, who turn the
G
handle of the machine A, consisting of a
pinion-wheel working into a large toothed
wheel, on the axis of which is an in-
dented wheel, round which an endless
chain passes, and also round a corres-
ponding wheel at the side of the one at
M
the foot of the vertical chain; the latter
is set in motion when the wheel A re-
volves, together with the endless chain
just described, over the indented wheels
at C and E, by which the chain oper-
ates its rotation. On the side of the
N
chain ascending, the workmen attach
their hods full of materials, by means of
a hook fixed in the hod, as at B, and
others detach them, as at F, to carry
them to the bricklayers on the scaffold-
I
ing. The empty hods are attached to
the chain on the opposite side, as at G,
and descend to the ground, where they
are detached, as at H.
The chain may be lengthened and
K
shortened as necessary. When a story
is added to the scaffolding, the trestle is
placed upon the new story, and the chain
lengthened as required. At the top is
a screw for tightening or relaxing the
chain, as occasion may require.
L
The figures I K L are accessories used
for hoisting the materials, viz: I, for bro-
H
ken bricks; K, for water; and L, for
pieces of stone for windows, chimneys,
&c. M is an enlarged view of the in-
dented wheel, and N the chain.
C
The advantages of this machine are,
that it relieves the workman from the
D
most toilsome part of his labor, by doing
away with the practice of ascending the
E
ladder; and it prevents, as far as possi-
ble, the accidents arising from this prac-
tice, to which he so often falls a victim.
A
It also enables building operations to be
carried on with much greater expedition
than heretofore; and at the same time it diminishes the cost of such works.
DYNAMICAL TABLE of the strength of a man, showing the number of bricks that can be carried up a
ladder by an ordinary laborer.
Ft. in height. per min.
per hour.
in 10 hours.
Ft. in height. per min.
per hour.
in 10 hours.
10
90
5400
54,000
40
22
1350
13,500
20
45
2700
27,000
50
18
1080
10,800
30
30
1800
18,000
60
15
900
9,000
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ELLIPTOGRAPH.
ELLIPTOGRAPH. Fig. 1341 is a side elevation of the machine, showing the pencil adjusted for
describing an ellipse, and Fig. 1342 is a plan agreeing to the above. Fig. 1343 is a section of the slide
of the ball o which forms a universal joint for E the pencil-holder. Fig. 1344 is the arm C drawn dou-
ble size. Fig. 1345 is a section of the same arm, with its rocking slide-bar g. Fig. 1346 is the arm D,
drawn double size, with its rocking slide-bar f. Fig. 1347 is an end view of the bar f. Fig. 1348 shows
the bar f suspended from its top centre. Fig. 1349 represents the bar f generally used for ellipses of
ordinary proportions. A is the top frame of the instrument which carries the revolving or generating
circle B. C is the moveable centre arm which determines the major axis of the ellipse. D is the bottom
moveable arm which determines the minor axis. E is the pencil-holder, being a light brass tube, turned
exactly parallel; its use is to hold the describing pencil, which is fitted into its lower extremity, the
point being in a direct line with the axis of the holder. F is the bottom plate, into which the upright
pillar G is fixed, by means of the adjusting-screw H. The method of application of the instrument is
as follows :-Take a straight-edge T or T square, having previously drawn two lines at right angles
across each other, for the major and minor axes of the required figure; place the bottom frame, with the
centre marks a a on the line for the major axis, and the marks b b on the line for the minor axis, which
marks are inside of the frame F; then bring the straight-edge T against the side of the frame F and
1348.
1341.
"A
D
1347.
1343.
f
1349.
X
G
£
c
D.
D
1346.
E
F
H
D
1342.
1344.
F
1345.
9
J
C
C
B
F
T
fix it. If the ellipsis required is the largest of the set, let the slide with the ball o be pushed out 80
far as to bring the point of the pencil to the length of the major axis II, the generating circle having
been turned round until the sliding-groove, with the ball 0 is parallel with the major axis, that is, when
the arm C is about half height, the position shown, (this should never be higher but in extreme cases,
for the lower the cross-arms C and D are kept, the steadier will be the point of the pencil but if by
sliding out the ball 0, it is not enough for the ellipsis required, the arm C must be raised until the
point reaches the desired distance. When this is done, turn round the generating circle BB, until the
sliding-groove of the ball o is parallel with the minor axis J J, which will be at right angles to its former
position. Then slide the arm D up or down until the point of the pencil rests on the point of the minor
axis. and if by turning round the generating circle B B, the pencil point touches all the four points
[IJJ, the instrument is correct for that proportion of the ellipsis. With this single arrangement it will
now draw any number of sizes, from a more point up to the full capacity of the instrument, by simply
sliding the ball 0 out or in, until the point of the pencil reaches the point of either the major or minor
axis required. the generating circles having been turned round to suit either of them, as before. It is
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EMBOSSING MACHINE.
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immaterial to which of the axes it is set, as the instrument will always produce the same proportions of
ellipsis 80 long as the arms C and D are not altered. But if the major axis is required to be lengthened
or shortened without changing the minor axis, the arm C must be drawn up or down 80 as to bring the
pencil to the desired point; or if the minor axis is to be altered, the major axis remaining, the arm D
must be moved up or down until the pencil again rests on the point required; the generating circle in
either case having been turned round until the sliding-groove of the ball 0 is parallel with the axis of
the ellipsis to be altered, or, which is the same, with the sliding-groove of the opposite arm. To pro-
duce the figure, nothing more is necessary than to turn round the generating circle by the finger and
thumb acting on the studs SS, when the pencil point will trace the figure on the paper below; the
slide of the ball o should be so tight as not to alter with the action of the pencil. The particular use
of the straight-edge T, is to enable the operator to change the plane of the ellipsis and return again to
the same plane; all that is required being simply to bring the points a a to the line of the axis required,
such as I to I, &c. The closer the arms C and D are brought, the nearer will the ellipsis be to the cir-
cle, and if the rocking-bar f of the arm D, Figs. 1346, 1347, 1348, and 1349, is shifted to hang by the
top centre, as in Fig. 1348, the two arms C and D can then be brought quite close, and the centres of
suspension of both rocking-bars g and f in the arms C and D will be in the same plane, and yet both at
perfect liberty to vibrate with the pencil-holder which passes through both these bars as well as through
the ball O. In this case perfect circles will be produced, and if the arm D be lowered below that point
in the slightest degree, the ellipsis will vary in that proportion, and so on until the arm D reaches the
bottom. But if still further elongation is required, this arm D must be inverted, and the bar f again
suspended as in Fig. 1348, when a straight line will be produced if required, by bringing the surface
acted upon in the same plane with the centre of suspension of the bar f; and by raising the arm D in
the slightest degree, an ellipsis of that proportion will be produced, and 80 on as the arm D is raised.
EMBOSSING MACHINE, and Bookbinders' Arming or Stamping Press. With this machine the
pressure is applied by means of a treadle, thereby allowing the operator the use of both hands to feed
and fly with; also enabling him to apply an immense pressure with but little exertion. The form being
stationary, it may be heated by steam if required.
1350.
This machine is manufactured by R. Hoe & Co., New York. The embossing machines of Mr. D. Dick,
and of Mr. Austin, are also favorite machines with bookbinders.
EMBANKMENTS, Moveable Machine for executing. First employed on the St. Germain's Railway,
by M. CLASSEYRON, Engineer-in-Chief.
It consists of two trussed beams, which are laid with rails. It is placed at the head of the embank-
ment during the course of execution, the earth wagons being run upon it after being tipped. Suppose
59
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466
EMBANKMENTS.
the formation of an embankment proceeding from one end of a cutting, the baleine is placed as shown
in Figs. 1351 to 1356, with one end resting upon the embankment and the other laid in the same line of
direction, and supported on a wheel-carriage. The carriage stands on a small auxiliary railway pro-
ceeding from the lower level of the head of the embankment, the rails being taken up at one end as
the other progresses.
Upon a wagon being tipped, (at the battery head,) and the contents discharged between the rails, it
is then pushed to the further end of the baleine. This course is followed with a second wagon, which is
also discharged and run on the baleine, next the first, and it is continued until the baleine cannot
accommodate any more, when the whole of the wagons are carried back together to the places of filling,
by a horse or a locomotive engine.
.
a
1355.
H
O
A
B
c
1351.
1352.
a
1353.
SCALE.-17 feet=1 inch.
1354.
1356.
n
The workmen move the baleines forward upon the wheels of the carriage supporting it, by crow-bars
and other tools. They also raise it by ropes and pulleys to whatever height may be required at the
head of the embankment.
ENAMELLING. See GLASS and PORCELAIN.
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ENGINES, DETAILS OF.
467
ENGINES, DETAILS OF. Pumping-Engine.-In a pamphlet printed by Messrs. Boulton and
Watt, for the use of their workmen, some time between 1782 and 1785, we have some excellent practical
directions respecting the construction and management of pumping engines, the greater part of which
are applicable to the circumstances of the present time.
Directions for putting the engine together.-' Having put the working-beam together, and fastened
the gudgeon to it, rest it on the plummer-blocks; but do not fasten these blocks until the cylinder
is fixed.
Level the top of the stone platform, and lay the outer bottom of the cylinder down in its place,
truly level, and corresponding to the holding-down screw-boxes.
"Apply the inner bottom upon the outer one, and set its upper joint level, by wedging betwixt it and
the outer bottom, if it requires it; then cut out segments of pasteboard, such as is used for the boards of
books, (not such as is composed of paper pasted together let these segments be of such thicknesses as
the different parts of the joint may require, (if it be more open in some places than in others.) Soak
these pasteboard segments in warm water until they become quite soft, then lay them upon boards to
dry, and when quite dry put them into a flat pan with a quantity of drying linseed-oil; warm the oil
until the pasteboard ceases to emit bubbles of air, but take care not to heat the oil much hotter than
boiling water, otherwise it will harden or burn the pasteboard. Anoint the segments on both sides with
thin putty made with fine whiting and some of the linseed-oil; let the whiting be very dry, otherwise
it will be difficult to mix with the oil-and N. B,, that white lead will not answer in place of it.
" You must, as much as you can, avoid using more than one thickness of pasteboard, and the segments
should be a little broader than the flanch, with all the holes cut out by a chisel, but not quite so large
as the holes in the iron. The segments should also be thinned at the ends where they overlap each
other, so that they may form a circle of pasteboard of a uniform thickness.
To pack the piston, take sixty common-sized white or untarred ropeyarns, and with them plait a
gasket or flat rope, as close and firm as possible, tapering for 18 inches at each end, and long enough to
go round the piston and overlap for that length; coil this rope the thin way as hard as you can, lay it
on an iron plate, and beat it with a sledge-hammer until its breadth answers its place; put it in and
beat it down with a wooden driver and a hand-mallet; pour some melted tallow all round; then pack
in a layer of white oakum half an inch thick, then another rope, then more oakum, so that the whole
packing may have the depth of about four inches, or only three inches if the engine be a small one.
Cast segments of a circle of lead, about 12 inches long, 3 inches deep, and 11 inch thick, fitted to the
circle of the piston, and cut down square at both ends; lay them round upon the packing as close as
they can lie to one another without jamming, and screw down the piston-springs upon them; the piston-
springs should be bent downwards at the end next the piston-rod, and a little mortise should be cut in
the cast-iron there, for the bent-down point of each of them to lodge in, which will prevent their coming
forwards to touch the cylinder. Previous to the piston being put into the cylinder the hollows among
the crosses should be quite filled up with solid pieces of deal wood, put in radius fashion. The packing
of the piston should be beat solid, but not too hard, otherwise it will create so great a friction as to
hinder the easy going of the engine. Abundance of tallow should be allowed it, especially at first; the
quantity required will be less as the cylinder grows smooth.
The joints being all made, the regulator valves in their places, and the covers screwed on, but no
water in the condenser cistern, admit steam, and when the cylinder and steam-case are thoroughly
warmed, screw up the nuts of all your screws, and caulk the pasteboard or oakum of such joints as may
require it, with a caulking-chisel, until you find that every thing about the cylinder is perfectly stanch;
then pour three or four feet deep of water into the hot-water pump; stake down the injection and blow-
ing-valves, and also those on the air-pump lid; then let the steam into the condenser, which will show
the defects or leaks, if there be any.
'Screw on the steam-gage to the steam-case near the nozzle, and behind the engine-man's place;
pour as much mercury into it as will half fill the open leg; put a float on it, broad at bottom, but very
slender in the stem; cut the float or index off close to the end of the open tube, and fix a scale to it,
reckoning every half-inch the float rises equal to an augmentation of the elasticity of the steam, corres-
ponding to the supporting of a column of mercury an inch high, because the surface has sunk as much
in the one leg as it has risen in the other. Solder a small copper fosset-pipe, to fit the copper commu-
nicating tube of the barometer, into the eduction-pipe, 12 inches under the fosset of the blowing-valve,
and on the opposite side of the eduction-pipe; place the barometer in the door-way to the condenser on
the further side from the plug-tree, 80 that the engine-man may see it when at his station; join the
copper tube to it by pouring melted sealing-wax into the copper cup at top; fill the short leg of the
barometer with mercury, within four or five inches of its top, and put a light float in it, long enough to
reach to the top of its frame.
do Fill the condenser cistern, shut the lower regulator, and there being no steam in the cylinder, or its
communication with the boiler being cut off, take off the bonnet or cover of the exhaustion regulator,
shut that regulator, and work the air-pump by means of the brake. If then you find that air enters by
the regulator, pour some water on it, and continue pumping until you have raised the barometer, i. e.
sunk its float, to 27 or 28 inches; leave off pumping, and observe if the vacuum continues good, or is a
long time in being destroyed. If it loses fast, seek for the leaks, which must be somewhere in the
eduction-pipe, and will make a noise if touched with a wet hand, (observe if the condenser moves by
the pumping, and secure it.) And having cured these leaks, you may try the tightness of the cylinder
by staking the working-beam, so that the piston cannot descend; then taking the cover off the cylinder,
open the exhaustion regulator, and shut the steam regulator; on beginning to pump, you will perceive if
the piston be tight; if it is not it may be beat a little, and some water being thrown upon it, and on the
steam regulator, whatever air enters must be by leaks, which must be sought for and cured by screwing
or caulking in oakum.
N. B. A critical tightness in the piston cannot be obtained until the engine has gone a few days.
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ENGINES, DETAILS OF.
without beating it too hard, to permit the engine to move easily. When you can detect no more leaks
in this way, the steam must be admitted, and the same examination made as before.
" After the engine has been set agoing, and has gone a few hours, the holding-down screws should be
screwed tight, and so from time to time as they become slack; and in like manner all the other screws
about the cylinder or nozzles should be screwed up as they slacken, and the joints caulked and puttied
where they require it.
" Directions for working the engine.-To set the engine agoing, raise the steam until the index of the
steam-gage comes to three inches on the scale; when the outer cylinder is fully warmed, and steam
issues freely on opening the small valve at the bottom of the siphon or waste-pipe, which discharges
the condensed water from the outer bottom, open all the regulators; the steam will then forcibly blow
out the air or water contained in the eduction-pipe, by the blowing-valve, but cannot immediately take
place if the air is in the cylinder itself; to get quit of it, after you have blown the engine a few
minutes, shut the steam regulator. The cold water of the condenser cistern will condense some of the
steam contained in the eduction-pipe, and its place will be supplied by some of the air from the cylinder;
open the steam regulator and blow out that air; and repeat the operation until you judge the cylinder
to be cleared of air; when that is the case shut all the regulators, and observe if the barometer shows
that there is any vacuum in the eduction-pipe. When the barometer gage has sunk three inches, open
the injection a very little, and shut it again immediately; if this produces any considerable degree of
vacuum, open the exhaustion regulator a very little way, and the injection at the same time. If the
engine does not commence its motion it must be blown again, and the same operation repeated until it
moves. If the engine be very lightly loaded, or if there is no water in the pumps, you must be very
nimble and shut the exhaustion and top regulators so soon as it begins to move quickly, otherwise it
will make its stroke with great violence, and perhaps do some mischief. To prevent which, open the
top and exhaustion regulators only a little way and put pegs in the plug-tree, so that they may be sure
to shut these regulators long before the piston comes to the bottom.
If there is much unbalanced weight on the pump-end, you must also take care to put a peg in the
ladder which guards the steam regulator lever, so as to allow that regulator to open only a little way,
and so to lessen the passage for the steam when it enters to fill the cylinder, otherwise the rods, &c., at
the pump-end may descend too fast and be prejudicial; if you find, after a few strokes, that the engine
goes out too slow, the steam-regulator may be opened wider. In order to regulate the opening of the
exhaustion regulator you should have pieces of board, of various thicknesses, to put under the weight
which pulls it open, by means of which it may be made to open more or less at pleasure, and the top
regulator may be managed in the same manner.
'Should the engine work with too great violence, on account of its being underloaded, you may
correct it by giving the top regulator a lesser opening, and shutting it at such a part of the stroke as
will just give the piston sufficient force to come to the bottom. Whenever the top regulator is used the
exhaustion regulator should be thrown fully open every stroke, in order to give a free exit to the steam,
on which a great part of the good effects of the top-regulator depends.
The engine should always be made to work full stroke, that is, until the catch-pins come within half
an inch of the springs on each end, which is easily managed by an attention to the pegs. Care must be
taken that the piston rise high enough in the cylinder, when the engine is at rest, to spill over into the
perpendicular steam-pipe any water which may be condensed above it; for if any water remain there,
or in any other part of the cylinder while it is working, it will very much increase the consumption of
steam. When the engine is to be stopped shut the injection and secure it; put a peg in the plug-tree
to prevent the exhaustion regulator from opening, and take out the peg on the other side so as to allow
the steam regulator to open and to remain open: otherwise you may have a partial vacuum in the
cylinder, and it may be filled with water from the injection or leakages, which is a troublesome accident.
The top regulator should also be open while the engine stands.
" When an engine is in tolerably good order it will bear to stand ten minutes, and go to work again
without blowing afresh; and though it has stood two or three hours, if there has been any steam issuing
from the boiler, and no air has been admitted into the cylinder, it will generally go off with once blowing
for about a minute.
If you find, after following the above directions, that the engine does not go to work, shut the
exhaustion regulator and give some injection; if it then makes no vacuum, it is likely there are air-leaks
about the eduction-pipe; if it does make a vacuum which remains but a short time, it may be owing
either to air or water leaks; these may be distinguished by blowing as before, and shutting the lower
regulator for about a minute without giving any injection. If, upon opening it again, it throws out a
good deal of water at the blowing-pipe before it blows steam, it is certain that it either has some leak
in the condenser under water, or that the injection or blowing valve does not shut close; if they are
found to shut close, every joint should be examined, and also the valve at the foot of the eduction-pipe.
If, after blowing as before, you find that immediately on opening the exhaustion regulator a quantity
of air is thrown out at the blowing-valve, the leak is in the eduction-pipe, somewhere between the
surface of the water in the cistern and the nozzle. The particular place of these leaks may be found
by emptying the cistern of water, putting three or four feet deep of water into the hot-water pump, and
staking down the blowing and injection valves with those on the air-pump lid; then, if steam be
admitted into the eduction-pipe it will come out at the leaks and point them out. If not found out in
this way, apply the brake to the air-pump, taking care first to put some water on its bucket, and then
by working that pump by hand, you will probably, on an attentive examination, observe where air goes
in, which may be known more distinctly by wetting the place suspected.
If upon shutting the lower regulator and making a vacuum in the exhaustion-pipe by pumping, or
by injection, you find the vacuum continues good for a considerable time, then the fault does not lie in
the eduction-pipe, but in the nozzle or joint of the cylinder bottom, where it must be sought for.
In these examinations by pumping it is proper to take off the bonnet or cover of the exhaustion
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469
regulator, and to examine if air enters at that regulator; if it does, and only in small quantity, throw
some water on the regulator while you are examining the eduction-pipe; and when the leak is suspected
to be in the bottom joint of the cylinder, or in the lower nozzle, you must throw some water on the
steam regulator and also on the piston, then, by pumping and strict examination, you will soon find
where the air enters. When you are examining the tightness of the piston by pumping, you must stake
the beam, 80 that the piston may not descend.
44 If in course of working you do not find the vacuum keep good, and the engine goes sluggishly, or
stops and requires to be blown frequently, you must examine whether an uncommon quantity of air or
water issues at the hot-water pump, or if any comes out at the valves on the air-pump lid; if the
quantity of air is great, the engine has some air leak; and if the quantity of water be great, and is cooler
than usual, it proceeds from a water leak in the condenser; if the quantity of water be great, and at the
same time very hot, it proceeds from a bad piston, or from the steam regulator not shutting close.
The engine will also go badly if the air-pump or water-pump buckets or clacks strip the water, that
is, let it pass by them. You will know if this be the case with the water-pump bucket by observing
whether the water follows down after it at the return of the stroke, and leaves a part of the pump
empty; if it does not, either the bucket strips the water or the engine receives water in some way which
it ought not.
" ttention ought to be given to feeding the boiler in a regular manner, that it may not be spoiled,
nor steam wanted. When there is too much water in the boiler the engine will not work regular, and
if there is too little the sides of the boiler will be burnt by the flame in the flues. If by accident it
should at any time run a little too low, the feed should be augmented 80 as to fill it gradually; for if
you run in too much at once, you will check the steam, and stop the engine; but if it be run very low,
stop the engine, open the puppet clack, and fill the boiler from the pool or reservoir, if you have one;
otherwise fill it by working the air-pump, having first staked down the valves on its cover and opened
the injection-valve. In working the engine the steam ought to be strong enough to make the index of
the steam gage stand half an inch high at least, otherwise air will enter at the joints of the boiler, &c,
and spoil the vacuum, 80 as to cause a good deal of trouble to get quit of it again. Therefore if you
perceive the steam-gage to be lower, stop the engine until it rises again. By a little attention you will
find the proper opening of the feeding-cock for any rate of working.
Let all the coals employed to feed the fire be thoroughly watered just before they are thrown on, as
that will prevent their being swept into the flues by the draught of the chimney.
The fire should be kept of an equal thickness and free from open places or holes, which are
extremely prejudicial, and should be filled up as soon as they appear; if the fire grows foul and wants
air, by clinkers collecting on the bars, they must be got out with a poker, but the fire should be as
little disturbed in that operation as possible, and the greatest care taken not to make any coals or coke
fall through which are not thoroughly consumed; it is very common for a fourth of the whole coals to
be wasted in this manner by mere carelessness. When the fire is newly made the damper should be
raised a little, 80 as to let off the smoke freely, but should be let down to its proper place so soon as the
smoke is gone off. The air door in the chimney should be always open more or less; it prevents the
flame from being sucked up the chimney, and very considerably increases the effect of the coals. Once
a month the boiler and flues ought to be cleaned, or oftener if the water be very subject to incrust the
boiler. Every morning the ashes ought to be taken out, the engine-house swept clean, and a view taken
of every part of the engine, to see that nothing be working out of its place or want oiling. Particular
attention ought be paid to the bolts and cutters of the great chains and piston-rod, so that none of them
get loose.
64 An engine, when in good order, ought to be capable of going so slow as one stroke in ten minutes,
and so fast as ten strokes in one minute; and if it does not fulfil these conditions, somewhat is amiss that
can be remedied.
'The hot water should issue of the heat of 96° of Fahrenheit's thermometer, that is, blood warm, when
the engine is in excellent order, and should never exceed the heat of 110°, unless when the injection or
cold water is hotter than 70°, and in that case the vacuum will not be good.
To make putty for making or repairing the joints.-Take whiting, or chalk finely powdered, dry it
on an iron plate or in a ladle until all the moisture be exhaled: then mix it with raw linseed-oil, and
beat or grind it well, adding more oil or whiting until it be of the consistence of thick paint, and per-
fectly free from lumps or inequalities.
For some purposes, where the putty is wanted to dry and to be very sticky, use painters' drying oil,
which is made by boiling the oil with a small quantity of litharge or red-lead.
" Where the putty is wanted to continue always soft, mix about two ounces of butter or common
salad-oil with each pound or pint of the linseed-oil This soft putty is principally useful in the caulked
joints of the eduction-pipe above water. N. B. White-lead will not answer in place of the whiting.
" No wet cloths should be suffered to be laid on the cylinder, boiler, or steam-pipes, and every part
containing steam should be guarded as much as possible from the influence of cold air or water.
The proper grease for the piston and cylinder stuffing-box is melted tallow, and for the chains,
gudgeons, dc., common Spanish olive-oil, which, for some uses, may be thickened by dissolving some
tallow or butter in it by means of heat. Linseed-oil should never be used as grease, as it dries and
creates more friction than would have been without it. Hogs' lard, or train-oil, if applied anywhere
about the cylinder, or where it is hot, will thicken like linseed-oil When the oil or grease about the
great chains, or any of the working parts, grows clotted or very thick, it should be scraped off before
new grease is added.
An improvement has lately been made in the covering of boiler tops. The setting being built up to
nine inches above the flues as usual, a course of horse or cow dung, three inches thick and well beat, is
applied to the boiler top; on the outside of that is laid some good lime mortar, about an inch in thick-
ness, to which is applied a course of bricks flatwise, with their ends upwards; on the outside of that
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another course of bricks (also laid in good mortar) in the same position, but 80 as to break joint with the
first course; in which manner the covering is carried on until the whole top is covered, taking care to
leave an opening for the man-hole; every flanch may be thus covered, and when well done it effectually
makes the top steam-tight, and also defends it from cold and rain, 80 that a boiler-bouse is not necessary.
The mortar employed must be such as stands water.
" Additional observations.-Instead of using painters' drying-oil to make the joints with, take good
raw or unboiled linseed-oil, put it in an iron pot, place it over a gentle fire, (out of doors, but protected
from rain,) let it be watched as it heats, as it is very liable to boil over; when it boils make the fire
more moderate, but continue to heat the oil, until upon dropping soine of it upon a cold stone or piece of
iron, you find it is, when cold, of the thickness of thick tar or treacle. The pasteboards for the joints are
to be soaked in this oil warm, or painted over with it, and laid in a hot place to suck it up; and it is
also to be used to make the putty with.
The oakum with which the joints are caulked should be well smeared with the strong or thick boiled
oil mentioned in these additional directions. If the under side of the pipe of the inner bottom does not
fit close to the lower edge of the opening made for it in the outer bottom, that is to say, if the space left
there for pasteboard or caulking be wider than one quarter of an inch, a piece of hammered iron an inch
and a half broad must be forged of such thickness as to fill up the space, 80 as to make it tight by the
help of a thickness of pasteboard above it, and another below it. Lead ought not to be used in these
cases, as its expansion and contraction by heat and cold are too great. Instead of putting a prop from
the nozzle to the ground, it is found better to put a balance beam off sideways under the floor with a
short upright having a flat end to take a broad bearing under the nozzle. The weight of the balance
should not support more than two-thirds of the weight of the nozzle.
Some people use a plaited rope to make the joint of the cylinder lid, which is a bad practice for
though a plaited rope may make a joint apparently steam-tight, yet it has been found by experience,
that such joints are not air-tight; but when, by the working of the top regulator, a partial vacuum is
produced in the upper part of the cylinder, they permit some air to enter imperceptibly, and without
noise, which, of course, passes to the condenser, and by persons that are not aware of this circumstance,
may be thought to enter at some air leak in another place. We therefore recommend that this joint be
always made with pasteboard and putty; and that a strict attention be paid to the tightness of the
stuffing-box, wherever the top regulator is used."
In the Cornish engines great diminution in the consumption of fuel has taken place, chiefly by the
larger application of the principle of expansion. An 85-inch cylinder engine, erected at the United
Mines in 1840, reached in 1842 an average duty of 107 millions of pounds raised 1 foot high with a
bushel of coals. In this engine the pressure of the steam is 40 lbs, and it is cut off at one-tenth or one-
twelfth of the stroke. To diminish the risk of fracture in engines using such high steam, the double
cylinder engine is employed. The small cylinder here stands on top of the large one, and the same
piston-rod passes through both. The same number of valves too that is used in common pumping-
engines, suffices in this modification of the double cylinder plan.
The Cornish engines are provided with a steam-jacket, but through this jacket the steam does not pass
in its way to the cylinder. The steam jacket is kept filled with steam by a branch from the steam-pipe,
which is about 4 inches in diameter in large engines. The clothing applied to the cylinder is very
various a common plan is to enclose the cylinder in a brick wall, leaving a space between them; to
plaster the wall, and coat it with timber. The cylinder cover and cylinder bottom are usually made
hollow, and filled with steam they are then carefully coated with non-conducting materials.
The main beam of the engine usually consists of two cast-iron plates, bolted together, and armed with
projecting horns to catch the spring beams, should the piston be disposed to strike the bottom of the
cylinder. From the beam hangs the plug-rod, by which the valves are moved by means of some such
arrangement as that shown in Fig. 1358, which differs in some respects from the Cornish form. The
valves of the Cornish engine erected
1357.
by Mr. Hosking are shown on a large
scale in Figs. 1357, 1359, and 1360.
c
These valves are of the equilibrium
description. Figs. 1357 and 1359,
the valve to the-left is the governor-
valve, by the adjustment of which
the flow of steam to the cylinder is
regulated; the centre valve is the
o
o
o
steam-valve; and the valve to the
right is the equilibrium-valve. Fig.
c
1360 represents the eduction-valve,
which, it will be remarked, is larger
SCALE.-4 feet=3 in.
than the others, so as to afford a free
exit for the steam into the condenser. Three-quarters of a square inch per horse power is a common size
for the steam-valve in rotative engines, furnished with spindle-valves; and a square inch and a quarter
per horse power is a common size for the exhaustion-valve.
The plunger-pump is the pump universally used in the Cornish mines, and it is much preferable to
the lifting-pump, as it can be packed afresh, or the packing may be tightened, with much greater facility
than can be done in the case of a lifting-pump, while the friction is at the same time less. The shaft is
divided into a succession of lifts, in which the water of the lowest lift is delivered to the pump next
above it, and 80 on in succession until the water reaches the surface. The plunger-pump is used in all
these lifts except the lowest, where the lifting-pump is used, with the view of obviating inconvenience,
should the water from derangement in the machinery, or otherwise, rise so high in the mine as would
make the valves and barrel of a forcing-pump inaccessible, and also on account of the facilities afforded
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1358.
ENGINES, DETAILS OF.
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ENGINES, DETAILS OF.
by the lifting-pump in the drainage of the water as the mine is sunk deeper. The plunger-pump ob-
viates the necessity for as large a counterweight as would otherwise be necessary; for the force of the
engine is expended in lifting the pump-rods, and the water is forced out by the weight of the pump-rods
in their descent. The pump-rods of some of the engines, however, are too heavy for the engine to lift,
and part of the weight has to be taken off by one lever or more, provided with counterbalance weights,
placed either at the surface or in some convenient side excavation. The main pump-rod of Davy's engine
at the Consolidated Mines, is one-third of a mile in length, and weighs 95 tons. The other rods weigh
40 tons, making a total weight of 135 tons, of which 39 only are wanted to balance the water in the
1359.
1360.
SCALE.- inch=1 foot.
pump, and the greater part of the remaining 96 is balanced by weighted levers. The main pump-rod
is usually composed of balks of Memel timber, and at intervals down the sides of the shaft projecting
pieces are bolted on, which catch upon suitable timbers let into the sides of the shaft, to prevent the rod
from descending too far in the event of fracture above. The rod is guided at intervals by appropriate
frames. There is something rather primitive in these expedients, and it is not improbable that the
whole of this cumbrous apparatus will hereafter be superseded by machinery operating by atmospheric
pressure, whereby the pump-rods will be rendered superfluous, or else by the centrifugal pump; and a
small engine, working at a quick speed, will suffice for working such an apparatus.
TABLE OF OBSERVATIONS UPON TEN CORNISH ENGINES.
CONSOLIDATED MINES.
UNITED MINES.
Taylor's
engine.
Davy's
engine.
Job's
engine.
Woolf's
engine.
Bawden's
engine.
Pearce's
engine.
Cardozo's
engine.
Eldon's
engine.
Loam's
engine.
Hosking's
engine.
Diameter of cylinder-in inches
85
80
65
90
90
65
90
30
85
85
Dimensions
of engine.
Stroke of piston-in feet
10
111
9
10
10
9
9
9
10
10
Diameter of steam-valve-in inches
12
13
9
8
8
7
10
5
10
12
"
equilibrium-valve-in in.
16
18
12
16
16
12
13
7
16
16
"
exhaustion-valve-in in.
20
24
14
19
19
14
15
10
19
19
Number of boilers
4
3
2
4
3
3
3
1
3
3
Length of boilers-in feet
3-36
....
-
37
(31)
1·40
(32)
35
36
36
36
-
1-32
36
2-38
44
Dimensions of
Diameter of boilers
6f
7
6f
61
64
61
61
6f
6f
6f
boilers.
64
tubes
-
3.34
14
41
34
31
32
3
34
4
4
4
Length of fire-bare
4
4
4
4
4
4
4
4
4
4
Total area of fire-bars
63
52
30
60
45
45
48
16
48
48
Heating surface exposed to flues
3781
3151
1598
3481
2694
2694
2694
941
2952
3451
Water space-in cubic feet
2467
2025
1033
2140
1650
1650
1650
579
1706
2085
Steam space-
"
735
580
315
608
468
468
468
178
528
645
Open air-Fahrenheit
570
570
-
57°
57°
51°
55°
56°
51°
55°
Engine-house-Fah.
-
-
-
-
-
67°
-
55°
63°
66°
Temperatures
Ashes over boller-Fah.
80°
80°
81°
98°
98°
97°
990
79°
82°
observed.
88°
Cylinder cover-Fah.
111°
90°
1020
126°
96°
109°
94°
98°
90°
84°
Middle of cylinder clothing-Fah.
W 77°
W 76°
95°
102°
B 140°
I
B790
W 600
W67°
W 68°
Clothing of steam-pipe-Fah.
79°
-
-
130°
95°
-
140°
970
80°
Rgo
Condensing-water-Fah.
640
840
58°
115°
110°
57°
60°
61°
63°
60°
Hot well-Fah.
980
100°
91°
140°
140°
970
1040
94°
102°
96°
Height of condenser barometer-in in.
274
27f
-
251
-
-
-
-
-
27f
Number of plunger-pumps
9
12
2
7
8
9
8
1
5
5
bucket-pumps
2
2
-
1
2
2
2
-
4
3
Water load per sq. inch cf piston in lb.
11.46
13.12
8.78
11.56
83
16-8
11.5
17.96
11:95
13.58
Proport'n of stroke where steam cut off
1-5th
1-5th
-
$
1
t
t
Strokes per minute
8f
7j
10
81
I
2-11ths
-
-
on
8
7
Proportion of duration of in-door to
out-door stroke
}
4:7
5:8
4:7
5:7
5:7
5:6
4:0f
4:7
1:8
4:71
Grease used per day-in lbs.
12
12
10
12
12
10
12
6
12
12
Oil used per day-in pints
1
1
1
1
1
1
1
Men employed
4
4
3
was
1
1
4
4
3
4
3
4
4
Boys employed
3
3
3
4
4
3
3
-
3
3
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ENGINES, DETAILS. OF.
473
1363.
1302.
+
10
,
K
c
D
Working-beam.-SCALE.-$ - inch=1 feot.
60
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ENGINES, DETAILS OF.
A bushel of Welsh coal now used in Cornwall weighs 94 pounds.
Rotative engines.-A rotative engine of Messrs. Caird's, is represented in Fig. 1361, which is a general
elevation.
1361.
1364.
1365.
SCALE.- inch=1 foot.
1366.
Figs. 1362 and 1363 are en-
larged views of the working-
beam, which is of cast-iron;
and Figs. 1364 and 1365 are
sections of the same. The
sizes of this beam agree, with
tolerable nearness, with those
given in our tables of dimen-
sions. The depth of beam at
1367.
1368.
the centre is usually about
equal to the diameter of the
1,3
cylinder, and the depth at the
ends is generally made about
one-third of the depth of the
beam at the centre. The
length of the beam is gener-
ally about three times the
length of the stroke, and the
1369.
1370.
thickness 1-108th of the length.
2t
By the thickness is meant the
mean thickness: the edge-bead
1.4
is usually 11 time the thickness of the web.
SCALE
inch=1 foot.
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Fig. 1366 is the cast-iron main centre of the working-beam; Fig. 1367 is the cast-iron stud for the
main links; Fig. 1368 is the connecting-rod stud, of cast-iron; Fig. 1369 is the wrought-iron stud for the
air-pumps; Fig. 1370 is the wrought-iron stud for the hot and cold water pumps.
The diameter of the end studs of the beam is generally made about 1-9th of the diameter of the cylinder
when the studs are of cast-iron, and 1-10th of the diameter of the cylinder when they are of wrought-
iron; but the larger proportion is preferable, as the wear of the brasses is then less rapid. It is a com-
mon fault to make bearings too small, from their proportionment being viewed with reference only to
strength, whereas it should also be viewed with reference to wear.
Figs. 1371 and 1372 are views of the piston-rod clutch or cross-head. The piston-rod passes into the
round hole in the centre of the clutch, and the main links encircle the projecting bearings, and join the
clutch with the main beam. Fig. 1373 represents the cross-head gibs and cutter.
1371.
1374.
1375.
1372.
1376.
SCALE.-11 inch=1 foot.
1373.
SCALE.-11 inch=1 foot.
1377.
1378.
1379.
SCALE.-11 inch=1 foot.
SCALE.-11 inch=1 foot.
Figs. 1374 and 1375 represent the main links: Fig. 1376, the pillar of the main link,
which is interposed between the upper and under brasses; and Figa. 1377, 1378, and
1379 the upper brass and pillar-plate of the link. Fig. 1380 represents the gibs and
cutter of the main links. The sectional area of the main links is usually made about
1-113th of the area of the piston, that of the piston-rod being 1-100th. To find the proper
sectional area of the main links, a common rule is to divide the square of the diameter of
the cylinder by 144. The length of the main links is usually about the same as the length
of the crank, which is half the stroke. The main beam is always somewhat longer than
the distance between the cylinder and crank centres, and at the cylinder end the perpen-
11 inch=1 foot. dicular centre line divides the versed sine equally. The angular motion of the beam is
about 38° during the whole stroke. The length of stroke is the chord of the arc the centre
of the end pin describes, and the versed sine represents the amount of deviation from the perpendicular,
which is called the vibration of the beam. The beam being three times the length of the stroke, the dis
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476
ENGINES, DETAILS OF.
tance from the main centre to the end stud is one and a half times the length of the stroke, and with these
proportions the end stud will deviate from the perpendicular one inch for every foot of stroke. To find
the amount of vibration of the end stud from the square of the radius in inches described by the stud,
subtract the square of the length of the crank in inches; extract the square root of the remainder, which
deduct from the radius in inches. To find the proper distance between the main centre and the centre
of the cylinder: add the above-mentioned square root to the radius of the lever in inches; half their
sum will be the horizontal distance in inches.
The main centre of a land-engine beam is usually fixed in with
1380.
keys; the other centres are sometimes fixed with keys, and at
other times they are ground in, which appears to be the preferable
practice. The beam is set upon its edge on two blocks of wood; a
straight-edge is applied to ascertain if it is nearly straight, and if
bent or twisted it is brought straight by being hammered with the
face of the hammer, though this practice weakens the beam if
carried far. A cross-piece of wood is put into each main-centre
SCALE.-11 inch=1 foot.
hole, upon which the central point is marked; the beam is plumbed,
the end centres are put through, staked with wedges, and levelled by means of a short level with two
legs passing down from the edge of the beam. The lengths from the main centre are next ascertained
to be right, and the main centre is then put in, using the end centres as points to measure from.
Finally, the keys are fitted. This is the mode of procedure when the holes for the centres are not bored
out. It is expedient to put a centre line on the edge of the beam to fix the position of the studs
laterally, and this is generally
1385.
done. The force acting at each
end of an engine-beam may be
taken at 14 pounds per circular
inch of the piston, or, if the
beam be supposed to be sup-
ported at both ends, it may be
taken at 28 pounds per circular
inch acting at the centre. The
depth of the beam at the ends
i.,10⁻s
being one third of the depth
SCALE.-11 inch=1 foot.
at the middle, to find the di-
mensions at the middle, divide
1386.
the weight in pounds acting at
the centre by 250, and multiply
the quotient by the distance in
feet between the supports. To
find the depth, the breadth
being given, divide this product
by the breadth in inches, and
extract the square root of the
quotient, which is the depth. It
is expedient, however, to make
main beams stronger than is in-
SCALE.-11 inch=1 foot.
dicated by any of these rules, as
a higher pressure of steam is now used almost universally than was employed by Mr. Watt. In our
rules for the dimensions of beams at the centre, the resulting figures represent the web of the beam, or
the dimensions within the beads, if the pressure of the steam be above that of the atmosphere.
1387.
K
1388.
SCALE.-11 inch=1 foot.
The parallel motion.-Figs. 1381 and 1382 represent the radius bars, and Figs. 1383 and 1384 the
parallel bars. The screws at the end of the parallel bars enter holes in the cross-bar shown in Figs.
1385 and 1386, and to the exterior bearings of the same cross-bar the radius-bars are attached, the other
ends of those bars being attached to studs fixed to the spring beams in the line of the piston-rod.
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SCALE.-11 inch=1 foot.
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1390.
1389.
1391.
1393.
1392.
it
SCALE.-11 inch=1 foot.
Figs. 1387 and 1388 represent the
1395.
back links, the upper brass of which en-
circles the air-pump stud in the beam
1396.
the middle brass receives the cross-head
on the top of the air-pump rod, and the
lowest brass connects with the cross-bar
of back links, Fig. 1386, through the oval
hole in which the air-pump rod passes.
The sectional area of the back links is
made the same as that of the air-pump
rod, which is one tenth of the diameter
of the air-pump, or one twentieth of the
diameter of the cylinder. The sectional
area therefore of the two back links taken
together is equal to the area of a circle
one-twentieth of the diameter of the
cylinder; but in practice they are gen-
erally made of somewhat stronger pro-
portions.
The best proportionment of the par-
allel motions of land engines, and that
now followed universally, consists in
making the radius and parallel rods of
exactly the same length, and this length
equal to half the radius of the great
beam. The stud from which the back
links are hung is in this case situated
midway between the main centre and
the end stud of the beam, and the studs
in the spring beams round which the
radius bars move, are in the same verti-
cal line as the centre of the cylinder.
To find, therefore, the right position for
those studs, measure down perpendicu-
larly from the centre of the end stud,
when the beam is level, to a distance
equal to the length of the main or
back links, and at this distance draw a
horizontal line on the inner sides of the
spring beams. Then set off from the
main centre on this line the distance
between the main centre and centre of
the cylinder; the point of intersection is
the right position of the studs in the
spring beams to which the radius or
bridle rods are attached.
The back links and the main links are
always of the
1397.
same length, and
,,77
are now gener-
ally made half
the length of the
stroke, or the
length of the
crank, as we have
already stated.
The air-pump
cross-head is in-
SCALE.-1t inch=1 foot.
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ENGINES, DETAILS OF.
serted in the back links at the middle of their length. This point in the back links moves, it is
obvious, in the vertical line, for as the top of the links follows the motion of the main beam, and the
bottom that of the radius bars, which have the same radius and the same length of motion as the stud
in the beam from which the links are suspended, the central point of the links will have motion in a
curve equally removed from that of each end, which will be a straight line very nearly. The line traced
1402.
1404.
1408.
1409.
1
1403.
2
4
00
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1
4
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1407.
1405.
1
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by the parallel motion is not precisely a straight line, but a species of S
1406.
curve; it approaches to a straight line, however, with sufficient nearness for
every practical purpose. Notwithstanding the elegance of the parallel motion,
Brass Stude.
as an expedient for maintaining the perpendicular position of the piston-rod,
it is questionable whether guides are not to be preferred. In this country
they are very generally used, even with very long strokes and very short
beams; and in some of the steam vessels in England they have been substi-
X
do
2
tuted with advantage. The adjustment of parallel motions is a difficult task
and unless the parallel motion be very true it will be difficult to keep good
packing in the stuffing-box, and the cylinder will speedily be worn oval.
Figs. 1389 and 1390 represent the air-pump cross-head, which fits into the
central brasses of the back links. Fig. 1391 is the pillar which fits between
the brasses; and Figs. 1392, 1393, and 1394, are different views of the brasses, &c., of the air-pump
cross-head. The parts appertaining to the air-pump are made of the size that would be requisite for a
cylinder of the same diameter.
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ENGINES, DETAILS OF.
481
Figs. 1395 and 1396 are views of the connecting-rod, which is of cast-iron. Malleable iron connecting-
rods are now coming into use for land engines, and they are in every way preferable. When the con-
necting-rod is of cast-iron, of the form represented in the figure, the breadth across the arms of the cross
is made about 1-20th of the length of the rod; the sectional area at centre of rod 1-28th of the area of
the cylinder, and the sectional area at ends of rod 1-35th of the area of the cylinder. Fig. 1397 shows
the form of sectional area at centre. The length of the connecting-rod is generally made about three
times the length of the stroke. The diameter of the crank-pin is about one-sixth of the diameter of the
cylinder, and is generally made of cast-iron in land engines. The gudgeons of water-wheels are
generally loaded with about 500 pounds for every circular inch of their transverse section, which is
nearly the proportion which obtains in the end studs of engine-beams, but the main centre is usually
loaded beyond this proportion. To find the proper size of a cast-iron gudgeon adapted to sustain a
given weight, multiply the weight in pounds by the intended length of bearing expressed in terms of
the diameter, divide the product by 500, and extract the square root of the quotient, which is the
diameter in inches. For malleable iron the operation is the same, but the divisor may be made 1,000
instead of 500. These strengths are not intended to resist torsion, but are those proper for gudgeons.
Experiments upon the force requisite to twist off cast-iron necks show, that if the cube of the diameter
of the neck in inches be multiplied by 880, the product will be the force of torsion in pounds which will
twist them off when acting at 6 inches radius. The strength for cast-iron crank-shafts may be determined
by multiplying the square of the diameter of the cylinder in inches by the length of the stroke in feet,
multiplying by the decimal -15, and extracting the cube root of the product, which is the proper
diameter of the shaft-neck in inches. This rule has reference not merely to torsion, but also to the
strength as a gudgeon necessary to sustain the fly-wheel.
Messrs. Fenton and Murray use the following rule for determining the weight of the fly-wheel:-
Multiply the number of horse power of the engine by 2,000, and divide the product by the square of
the velocity of the circumference of the fly-wheel in feet per second; the quotient is the proper weight
of the fly-wheel in hundred-weights. To find the weight of the rim of a fly-wheel in pounds, multiply
the mean diameter of the rim in feet by the area of its transverse section in square inches, and multiply
the product by 9817 pounds. This gives the weight of the rim in pounds when the sectional area is
determined. Mr. Farey gives the following rule for determining the proper quantity of cast-iron in a
fly-wheel in cubic feet :-Multiply the mean diameter of the rim by the number of its revolutions per
minute, and square the product for a divisor; divide the number of horse power exerted by the engine
by the number of strokes the piston makes per minute; multiply the quotient by the constant number
2,760,000, and divide the product by the divisor found as above. The quotient is the requisite quantity
of cast-iron in cubic feet to form the fly-wheel rim.
In large engines each arm is cast separate, and after having been fitted to the central boss, the rim of
the wheel is fitted to the arms in segments. In small engines, an arm and a segment are generally
cast together. In mill engines it appears expedient to work with a short stroke and rapid piston,
whereby the fly-wheel is de more effectual, or a smaller one will suffice.
We do not approve of the plan of putting cast-iron cranks on hot, as the cye is liable to be cracked
in the process: it is preferable, we conceive, to grind them upon the shaft, and then to fix them by
means of a strong square key, such as that shown in Fig. 1399. In cranks which are put on hot it is
expedient to recess the crank-eye a little, 80 as to enable the collar upon the shaft to enter it, as the
crank contracts sideways in the act of cooling; and unless the collar be recessed a space will be left
between it and the crank-eye, which will be a disfigurement. The crank-pin is made slightly taper, and
is fixed in by means of a key.
Figs. 1400 and 1401 are representations of the eccentric-rod, and Figs. 1402 to 1409 are views of the
several parts of the governor. We have given rules for determining the proportions of governors, and
the arrangement of the parts here figured will be apprehended by a reference to Fig. 1402. The
upright revolving spindle on which the collar shown in section, Figs. 1405 and 1406, slides, and the curved
guide, Figs. 1408 and 1409, is fixed. From the top of the spindle, the arms, Fig. 1402, are suspended,
with the balls at the end, the arms moving in the slit in the curved guides, Figs. 1408 and 1409. The
divergence or collapse of the balls causes the collar to
slide up or down on the spindle; and through a slit
shown in the spindle, (which is hollow,) this movement
is communicated to a rod sliding within it, which, by a
suitable attachment, moves the throttle-valve.
Horse power.
Diameter of
cylinder.
Length of
The speed given by Mr. Farey, in a table, from
stroke in feet.
Number of
strokes per
minute.
Speed in feet
per minute.
Effective pres-
sure per square
inch in lbs.
which the annexed is an extract.
In this table the pressure is taken to vary slightly
4
12
3
29
174
6.8
with the size of the engine; but Messrs. Boulton and
8
16
4
24
192
6.84
Watt now adopt a uniform pressure of 7 pounds on
12
19
4
25
200
6.88
the square inch, as a preferable element of computa-
16
211
41
23
207
6.91
tion. The speed of the piston in feet per minute is
20
about 128 times the cube-root of the stroke; and the
234
5
211
215
6.92
30
281
6
19
228
6.92
nominal horse power of an engine may be found by
40
311
7
17}
245
6.92
multiplying the square of the diameter of the cylinder
50
35g
7
17}
245
6.94
in inches by the cube-root of the stroke in feet, and
60
381
7
17}
245
6.94
dividing by 47. To find how many millions of pounds
70
401
8
16
256
6.94
are raised 1 foot high by the consumption of a bushel
80
431
8
16
256
6.94
or 84 pounds of coal :-Divide 16632 by the number
90
46g
8
16
256
6.94
of pounds of coal consumed per hour by each horse
100
48%
8
16
256
6.94
power; the quotient is the number of millions of
61
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ENGINES, DETAILS OF.
pounds raised 1 foot high by the consumption of 84 pounds of coal A bushel of Newcastle coal will
weigh about 84 pounds, but the Welsh coal is heavier.
If a cubic inch of water be supposed to produce a cubic foot of steam, and the latent heat of steam
at 212° be taken, with Mr. Watt, at 960°, or, in other words, the cubic foot of steam be supposed to
contain as much heat in the latent form as would raise the temperature of the cubic inch of water, if it
could be prevented from expanding, 960°, then the sum of the latent and sensible heats will be repre-
sented by 1172°. The temperature of the water discharged by the air-pump is about 100°, which,
taken from 1172°, leaves 1072°, which must be taken up by such a quantity of cold water that its
temperature will not rise above 100°. If the temperature of the injection water be 50°, then the
difference between that and 100°, viz. 50°, is available for the absorption of the heat; and 1072 divided
by 50 = 21:44, which is the number of times the quantity of injection water must exceed the quantity
of water in the steam. To condense a cubic inch of water, therefore, in the shape of steam, 21.44 cubic
inches of injection water are necessary; but inasmuch as the water may not always be as cold as 50°,
Mr. Watt's practice was to allow a wine pint, or 28.9 cubic inches of injection water for every cubic
inch of water converted into steam. The capacity of the cold-water pump is usually made from one
thirty-sixth to one forty-eighth of the capacity of the cylinder. The injection orifice should have an area
of about one fifteenth of a square inch per horse power. The capacity of the hot-water pump should be
about one 240th of that of the cylinder, supposing that the engine is double-acting, and the pump
single-acting. The air-pump is usually made half the diameter of the cylinder, and half the stroke, or
one eighth of the capacity. The power requisite to work the air-pump is from one thirtieth to one
fortieth of the power of the engine. The openings through the foot and delivery valves are made of
about one fourth of the area of the pump. The internal diameter of the steam-pipe may be found by
dividing the horse power by 08, and extracting the square root of the quotient. We shall reserve what
we have to say on the subject of bolts until we come to speak of the holding-down bolts of marine
engines.
1410.
There are many other kinds of parallel motion besides those which we have mentioned, but there are
none of them of sufficient importance to justify a lengthened description. Fig. 1410 represents a spe-
cies of parallel motion invented by Mr. James White, and published in his New Century of Inven-
tions," in 1801. It depends on the principle that an encloidal curve, formed by one circle rolling within
another, becomes a straight line when the diameter of the outer circle is just twice that of the inner
one. A large wheel, with teeth on its inner circumference, is fixed on a frame concentric with the axis
and circle of the crank. A wheel with external teeth is fixed freely on the crank-pin and the point of
attachment of the piston-rod. By this arrangement the small wheel is compelled, by the pressure of
the piston-rod upwards, to roll round the great circle, ascending on the one side, and descending on the
other, so that the distance of the end of the piston-rod from the point of contact of the circles is always
equal to the distance of the circle from the diameter. The fault of this species of parallel motion is, that
the socket in the centre of the revolving wheel is exposed to a strain equal to twice that on the piston,
and which it cannot conveniently be made long enough to resist, 80 that it is liable to break or speedily
shake loose. In the plate of direct-action engines, various modifications of the parallel motion will be
observed. In the Gorgon engine, by Messrs. Seaward, the parallel motion is formed by the application
of a radius-bar to the air-pump lever, whereby one radius is made to counteract the other,-the centre
of the lever resting upon a jointed pillar, in order to enable the cylinder end of the lever to move up
and down in a vertical line. This species of parallel motion is sometimes made with a horizontal slide
for the centre to move in, instead of a vibrating pillar or link; but a slide works slack sideways, and is
not satisfactory in practice. The combination might be improved by causing the sliding ends of the
rods, which in some cases are used instead of a lever, to work into stuffing-box tubes hung on a centre,
so as to enable them to swivel. The rods, so soon as any wear took place, could be tightened afresh by
screwing up the packing.
Marine engines: Cylinder.-In the marine engine the cylinder-bottom is more frequently cast in,
than in land engines, and a plug of metal is fitted into a hole in the centre of the bottom, which is left
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ENGINES, DETAILS OF.
483
to allow the boring-bar to pass through. It is necessary that the cylinder should be bolted very firmly
to the sole-plate, as in engines which exhaust at the under side of the valve-casing, an air-tight joint has
to be made between the sole-plate and the part of the cylinder-bottom next to the valve. A cylinder
of about 6 feet diameter is usually made about 11 inch thick, and the metal should be hard as well as
solid. Messrs. Maudslay's practice in side-lever engines is to cast the cylinder-bottom in, up to 60 inches
diameter, and above that size they prefer casting the cylinder open at the bottom, and making the bot-
tom out of the sole-plate. A projection is cast on the sole- plate, to go a certain distance into the cylin-
der, with a space hollowed out for the cylinder-port. The bottom joint should not be of rust, but metal
to metal-the bottom flange of the cylinder and the place on which it stands on the sole-plate being
both faced in the boring-mill. The cylinder cover should fit SO nicely as to be tight, by interposing a
piece of lead or a ring of wire gauze, smeared with white or red lead. In oscillating engines the cylin-
der bottom is generally cast in, whatever be the size of the cylinder.
The valve-casing should be attached to the cylinder by means of a metallic joint, or, in other words,
by fitting the surfaces SO accurately that a little red-lead interposed will make them tight. The valve-
casing can thus be easily removed at any time to repair the valve faces; whereas, if the joint of the
casing be of rust, the removal of the casing is an operation of much difficulty. The attachments of the
cylinder to the diagonal stay are very generally made too small; that is, the surface is too small, and
the flange too thick. A very thick flange cast on any particular part of a cylinder endangers the sound-
ness of the cylinder by inducing an unequal contraction. It is much the best way to make the flange
for the framing thin, and the surface large. The bolts, too, should be turned bolts, and nicely fitted.
Some persons make them with a nut at both ends, the body of the bolt being made with a little taper;
and the nut which answers to the head is screwed up after the conical part of the bolt has been drawn
into the hole by the nut at the point. The object of this plan is to facilitate the fitting; but if the fitting
be well done, it is unimportant whether it is done in this way or any other.
Cylinders are not now usually made with steam-casings, yet experiment has satisfactorily proved
that there is a loss of power consequent on their relinquishment. It is not very easy to discern the
cause of this loss, as there is more radiating surface in the casing than in the cylinder; yet the existence
of the loss is very certain. Mr. Watt, in some of his early trials, discontinued the steam-jacket; and he
found the consumption of fuel to be materially increased. He therefore again resumed it, but it has
been again discarded in most of the modern engines, except those of the Cornish construction. Escape-
valves, for letting out any water that may enter with the steam, are now usually employed in marine
engines: they may in most cases be applied conveniently to the ports of the cylinder, as shown in the
details of engines of the West India packets, and may be kept shut by a spring, in the same manner as
the safety-valve of a locomotive. Escape-valves should be placed on that side of the cylinder which is
nearest the side of the ship; so that the attendants may not be scalded by the issuing water if the en-
gine primes. The escape-valve is shown beneath the Plan of Cylinder" in the West India mail engine
details; and to those details the remarks which follow are to be understood to refer, except where
specified to the contrary. In boring cylinders of 74 inches diameter, the boring-bar must make one
revolution in about 41 minutes, so that the cutters will move at the rate of about 5 feet per minute. In
boring brass, the speed must be slower: the common rate at which the tool moves in boring brass air-
pumps is about 3 feet per minute. If this speed be exceeded the tool will be spoiled, and the pump
made taper. The speed proper for boring a cylinder will answer for boring the brass air-pump of the
same engine. A brass air-pump of 36} inches diameter requires the bar to make one turn in about 8
minutes, which is also the speed proper for a cylinder 60 inches in diameter. To bore a brass air-pump
36} inches in diameter requires a week, an iron one requires 48 hours, and a copper one 24 hours. In
turning a malleable iron shaft, 124 inches in diameter, the shaft should make about five turns per minute,
which is equivalent to a speed in the tool of about 16 feet per minute. A boring-mill, of which the
speed may be varied from one turn in six minutes to twenty-five turns in one minute, will be suitable
for all ordinary wants that can occur in practice.
Piston.-The proportion of taper given to the piston-rod where it fits into the piston, in the West
India mail engines is a good one; if the taper be too small, the rod is drawn through the hole, and the
piston is split. Small grooves are turned out of this piston-rod above and below the cutter-hole, and
hemp is introduced, in order to make the piston-eye tight. Most piston-rods are fixed to the piston by
means of a gib and cutter, as shown in the figures of details, but in some cases the upper portion of the
rod within the eye is screwed, and it is fixed into the piston by means of an indented nut. This nut is
in some cases hexagonal, and in other cases the exterior forms a portion of a cone, which completely
fills a corresponding recess in the piston. But nuts made in this way become rusted into their seat
after some time, and cannot be started without much difficulty. Messrs. Miller, Ravenhill and Co, fix
in their piston-rods by means of an indented hexagonal nut, which may be started by means of an open
box key. The thread of the screw is made flat upon the one side, and much slanted on the other,
whereby a greater strength is secured, without any disposition to split the nut. When pistons are made
of a single ring, or of a succession of single rings, the strength of each ring is tested previously to its
introduction into the piston, by means of a lever loaded by a heavy weight. The old practice was to
depend chiefly upon grinding, as the means of making the rings tight upon the piston or upon one
another; but scraping is now chiefly relied on. A slight grinding, however, with powdered Turkey
stone appears to be expedient, which may be most conveniently accomplished by setting the piston on a
revclving table, and holding the ring stationary by a cross-piece of wood while the table turns round.
-Pieces of wood may be interposed between the ring and the body of the piston, to keep the ring nearly
in its right position; but these pieces of wood should be fitted 80 loosely as to give some side-play, else
the ring will wear itself into a groove on the piston. Messrs. Penn grind their cylinders after they are
bcred, by laying them on their side, and rubbing a heavy piece of lead, made to the curve of the cylin-
der, and smeared with emery and oil, backwards and forwards by hand, the cylinder being gradually
turned round, 90 as to subject every part successively to the operation. The pistons are also ground
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ENGINES, DETAILS OF.
into the cylinders with great care, 80 that they are perfectly tight from the commencement. Messrs.
Penn's piston for oscillating-engines has a single packing ring, with a tongue-piece, as in Messrs. Mauds-
lay's and Messrs. Miller's arrangements. The ring is packed behind with hemp-packing, and
the piece which covers the joint is made of sheet-copper, and is indented into the iron of the
1411.
ring, so as to offer no obstruction to the application of the hemp. The ring is ground to the
piston only on the under edge the top edge is rounded from the inside to a point, and the
junk-ring does not bear upon it, but the junk-ring squeezes down the hemp-packing between
the packing-ring and the body of the piston. The metallic packing of the piston consists of
a double tier of rings, cut into numerous segments. We approve of the plan of adding a nut
to the top of the piston-rod, in addition to the cutter, for securing the piston-rod to the cross-
head, as shown in Fig. 1411, where the piston-rod is 7 inches in diameter, and the screw 5
inches: the part of the rod which fits into the cross-head eye, is 1 foot 51, inches long, and tapers
from 61 to 6 13-16th inches diameter. The proportion of taper is a good one: if the taper be
less, or if a portion of the piston-rod within the cross-head eye be left untapered, as is some-
times the case, it is very difficult to detach the parts from one another.
Cylinder cover.-The cylinder cover in plate of details is cast close, and a few holes are left for taking
out the core by, which holes are afterwards plugged up. An annular recess is left in the under side of
the cover, for the accommodation of the heads of the piston-bolts. The gland of the stuffing-box is
shown on a larger scale on the same plate. Fig. 1412 repre-
sents the stuffing-box of the Don Juan steamer, cylinder 68
inches diameter. This appears to us better than that of the
West India packets: there is a great advantage in a deep
1412.
stuffing-box, especially in the case of vessels intended to
perform long voyages. Fig. 1413 represents the cylinder
cover of a Cornish engine. The stuffing-box is provided
with a lantern brass, into which steam is admitted by a small
pipe. There is packing both above and below the lantern
84
brass, to prevent any leakage of air by the stuffing-box;
for even if the packing be defective, it will be steam that
14/-
leaks in, which is condensable; and such a leak, though it
will increase the consumption of fuel, will not diminish the
K
10+
power of the engine. It is the usual practice to interpose
between the cylinder cover and the cylinder flange a gasket-
186
ring as a joint; but a joint of this kind leaks air impercep-
tibly, and it is better to make the surfaces very true, and
: to interpose either a ring of sheet-lead or a little red-lead
putty. It appears expedient to us that all marine engines
should be furnished with steam-jackets, and should also be
furnished with spaces in the cover and cylinder-bottom for
the admission of steam. Large engines, too, we conceive
should be fitted with the lantern brass stuffing-boxes.
Fig. 1414 represents the stuffing-box of the Trident, the engines of which are of the oscillating kind
by Messrs. Boulton and Watt. The extra depth of this stuffing-box is necessary to counteract the ten-
dency to wear oval. This tendency has not been found to occasion much inconvenience in oscillating
engines. In engines with the ordinary parallel motion the stuffing-box has a tendency to wear oval,
which may be perceived if attention be paid to the setting of the parallel motion. If the piston be
moved through a stroke, the gland will be found to move easily upon the piston-rod at some points, and
be jammed up tight in the stuffing-box at other points of the stroke; inequalities which clearly show
1414.
1413.
SCALE t inch=1 foot.
the existence of a very sensible deviation from a perfectly vertical motion. The brass dome attached
to the gland and embracing the rod, is an excellent addition; it keeps the grease employed to lubricate
the rod, from being split, and prevents grit and dust from getting into the gland, whereby in common
engines the rod is frequently much scratched and injured. Metallic packing in the stuffing-box has been
used in some engines, consisting in most instances of one or more rings, cut, sprung out, and slipped upon
the piston-rod, before the cross-head is put on, and packed with hemp behind. This species of packing
answers very well when the parallel motion is true, and the piston-rod free from scratches, and it ac-
complishes a material saving of tallow. In some cases a piece of sheet-brass, packed behind with hemp,
has been introduced with good effect, a flange, notched to permit the bending, being turned over on the
under edge of the brass, to prevent it from slipping up or down with the motion of the rod.
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Slide-valve.-The slide-valve represented in the plate of details is that known as the long D. The
valve-rod is attached to a cross-bridge in the plane of the under face, and the spring upon the rod is
sufficient to allow the valve to be tightened up as the face wears. In short D valves, where the valve-
rod is very short, the eye which attaches the valve to the rod has to be made oblong, Fig. 1415, or else
the holes of the casing-cover have to be made oval, so as to enable the valve-cover to be advanced
nearer to the cylinder, as the valve face wears. The valve-packings are introduced by doors at the
back of the valve-casing. and are pressed by blocks, of which one is shown in the same plate as the
valve. This block, it will be remarked, is in three pieces, which are tongued to one another; it is
pressed forward by means of screws, which pass through a cross-bar extending across the packing-port,
Fig. 1416, the ends of which rest in two angular lugs cast therein. The purpose of this bar is to pre-
vent the strain requisite for tightening the packing from being thrown upon the packing-door, which
would spring it out, and might cause the joint of the door to leak. In some cases the screws by which
the packing is pressed, pass through the door, and are made tight by a jam-nut, with a recess. into
which a turned part of the nut enters, as shown in Fig. 1417 a hemp washer being interposed at the
point of contact. In the plate, however, a different plan is shown, which is again represented in Fig.
1417. The packing-screws do not pass through the doors, but are kept short; and opposite to each
screw a plug is situated in the packing-door, which has to be withdrawn when the packing is to be
tightened. In each of these plugs a small recess is turned out, for the reception of a ring of hemp.
This recess is better half-round than square.
1416.
1415.
1417.
Some packing-blocks are tightened sideways, by screws which are inserted in the sides of the pack-
ing ports; but in the plate the block is tightened by its own wedge-shape point, which presses against
another wedge-formed piece, cast on the valve-casing, as will be understood by a reference to Fig. 1418.
In some cases the end of the packing abuts upon the cylinder face, but generally it overlaps two or
three inches in large engines, and a piece, a, Fig. 1419, is cast on each side of the cylinder port, in con-
tinuation of the circle of the valve, to furnish a surface upon which the packing may press. By this
expedient the chance of leakage at the corner of the valve is diminished, and the length of the packing
need not be adjusted with such critical exactitude as is necessary by the other arrangement. In some
engines the packing of the valve is put in like that of a piston, and is pressed down by means of a junk-
ring, but that plan is now little resorted to. Metallic packing has been tried in D valves, but only with
very moderate success. The kind that has answered best is a piece of sheet-brass, thinned at the ends,
bent to the shape of the valve, and packed behind with hemp.
1419.
1418.
1490.
There is a good deal of trouble with every modification of valve faces; but cast-iron working upon
cast-iron is perhaps the best combination yet introduced. The usual practice is to pin brass faces on
the cylinder, allowing the valve to retain its cast-iron face. Some makers employ brass valves, and
others pin brass on the valves, leaving the cylinder with a cast-iron face. Speculum metal and steel
have been tried for the cylinder faces, but only with moderate success. In some cases the brass gets
into ruts; but the most prevalent affection is a degradation of the iron, owing to the action of the steam,
and the face assuming a granular appearance, something like loaf sugar. This action shows itself only
at particular spots, and chiefly about the angles of the port, or valve face. At first the action is slow;
but, once the steam has worked a passage for itself, the cutting away becomes very rapid, and in a
short time it will be impossible to prevent the engine from heating when stopped, owing to the leakage
of steam through the valve into the condenser. However truly the D valve may be formed at first, the
face will become slightly hollow by the application of heat, as the circular will expand more than the
straight part, and the packing resists the enlargement of the circle. The cross-section will therefore
assume something of the form shown in Fig. 1420, where the dotted line represents the original position
of the face; and on examining a valve newly put in action, it will generally be found that it presses
hardest on the tails. The face therefore should be made slightly rounded in the manufacture; and if
the engine is a large one, the cylinder must not be faced when lying on its back, unless it has been
wedged up to the form it assumes when standing on end, else the partial collapse of the cylinder will
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ENGINES, DETAILS OF.
cause the face to become untrue. Copper steam-pipes seem to have some galvanic action on valve
faces, and malleable iron pipes have sometimes been substituted; but they are speedily worn out by
oxydation, and the scales of rust which are carried on by the steam, scratch the valves and cylinders, 80
that the use of copper pipes is the least evil. The valve-rod in that part opposite to the steam-port is
often much wasted by the steam; it therefore appears expedient to surround it by a copper pipe where
an injurious action is to be apprehended. The valve-casing shown in the plates is made close at the
bottom, the exhaustion being accomplished by the upper eduction-pipe. In cases in which exhaustion
is performed from below, it is expedient to cast two projections on the sole-plate, to prevent the valve
from falling down inconveniently far when the valve links are taken off. There is no expansion joint
introduced in the valve-casing of these engines, which is a serious defect, as the steam gains admission
to the valve-casing before it can enter the cylinder, and the joints are damaged, and in some cases the
cylinder is cracked, by the inequality of expansion of the cylinder and valve-casing.
In facing a valve recourse is had to the use of a face plate, to ensure the accuracy of the work. To
ascertain whether the face plate bears equally, smear it over with a little red ochre and oil, and move
the face plate slightly, which will fix the color upon the prominent points. This operation is to be re-
peated frequently, and as the work advances, the quantity of coloring matter is to be diminished, until
finally it is spread over the face plate in a thin film, which only dims the brightness of the plate. The
surface at this stage must be rubbed firmly together to make the points of contact visible, and the higher
points will become slightly clouded, while the other parts are left more or less in shade. If too small a
quantity of coloring matter be used at first, it will be difficult to form a just conception of the general
state of the surface, as the prominent points will alone be indicated, whereas the use of a large quantity
of coloring matter in the latter stages would destroy the delicacy of the test the face plate affords. The
scraping tool should be of the best steel, and should be carefully sharpened at short intervals on a Tur-
key stone, so as to maintain a fine edge. A flat file bent, and sharpened at the end, makes an eligible
scraper for the first stages; and a three-cornered file, sharpened at all the corners, is the best instru-
ment for finishing the operation. The number of bearing points desirable on the surface of the work
depends on the use to which it is to be applied, but in any case the bearing points should be distributed
equally over the surface. Great care must be taken in fitting valve faces that the valve be not made
conical: unless the back be exactly parallel with the face, it will be impossible to keep the packing
from being rapidly cut away. When the valve is laid upon the face-plate, the back must be made quite
fair along the whole length, by draw-filing, according to the indications of a straight edge; and the dis-
tance from the face to the extreme height of the back must be made identical at each extremity.
Should a hole occur either in the valve, in the cylinder, or any other part where the surface requires to
be smooth, it may be plugged up with a piece of cast-iron as nearly as possible of the same texture.
Bore out the faulty part, and afterwards widen the hole with an eccentric drill, 80 that it will be of the
least diameter at the mouth. The hole may go more than half through the iron: fit then a plug of cast-
iron roughly by filing, and hammer it into the hole, whereby the plug will become riveted in, and its
surface may then be filed smooth. Square pieces may be let in after the same fashion, the hole being
made dovetailed, and the pieces thus fitted will never come out.
Brass faces are put upon valves or cylinders by means of small brass screws, tapped into the iron
with conical necks for the retention of the brass: they are screwed in by means of a square head, which,
when the screw is in its place, is cut off and filed smooth. In some cases the face is made of extra
thickness, and a rim not 80 thick runs round it, forming a step or recess for the reception of brass rivets,
the heads of which are clear of the face.
Air-pump.-The air-pump is attached to the sole-plate by a rust faucet joint, which is preferable to a
rust flange joint, as the salt water eats away the heads of the bolts, unless they are copper; and if they
are copper, they waste the iron. The oil and grease which fall from the crank-pin upon the sole-plate,
deoxidize the rust of a flange joint, whereas with a faucet joint, suitably made, they cannot remain in
the same intimate contact. Short steel keys should be driven into the faucet in several places before
the joint is made, but they should not rise to the top of the faucet 80 as to divide the joint into segments.
The air-pump bucket is made with a junk-ring, whereby the packing of the bucket may be easily
screwed down. The valve is of the spindle or pot-lid kind. The foot and delivery are of the flap or
hanging kind. These valves all make a considerable noise in working, and are objectionable in many
ways. Valves of the same construction as those known as Harvey and West's, which are similar to
those shown in Fig. 1360, have been employed with advantage by Messrs. Rennie; and valves on
Belidor's construction, which is in effect that of a throttle-valve hung off the centre, were some years
ago proposed by us for the delivery and foot-valves. Some delivery-valve seats are bolted into the
mouth of the air-pump, apparently in the conviction that the pump-bucket never requires to be looked
at. If delivery-valves be put in the mouth of the air-pump at all, the best mode of fixing them appears
to be that adopted by Messrs. Maudslay. The top of the pump-barrel is made quite fair across, and
upon this flat surface a plate containing the delivery-valve is set, there being a small ledge all round to
keep it steady. Between the bottom of the stuffing-box of the pump-cover and the eye of the valve-
seat, a short pipe extends, encircling the pump-rod, its lower end checked into the eye of the valve-seat,
and its upper end widening out to form the bottom of the stuffing-box of the pump-cover. Upon the
top of this pipe some screws press, which are accessible from the top of the stuffing-box gland, and the
packing also aids in keeping down the pipe, the function of which is to retain the valve-seat in its place.
When the pump-bucket has to be examined, the valve-seat may be slung with the cover so as to come
up with the same purchase. For the bucket-valves Messrs. Maudslay employ two or more concentric
ring-valves, with a small lift. These valves have given a good deal of trouble, in consequence of the
frequent fracture of the bolts which guide and confine the rings; but their principle appears superior to
that of any of the other air-pump valves at present in common use, with the exception of the equili-
brated-valve, in which it is preferable that the face should fall in a groove filled with end-wood. It
would not be difficult to make this groove SO that the water would have to be forced out of it during
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487
the descent of the valve, whereby the shock would be still further diminished. It would be preferable,
however, if all these valves could be discarded in favor of a slide-valve, which might be applied to the
air-pump with much advantage.
The air-pump bucket and valves are all of brass, and the chamber of the pump is lined with copper.
It is now a common practice to make the chamber of the air-pump wholly of brass, whereby a single
boring suffices. When a copper lining is used, the pump is first bored out, and a bent sheet of copper
is introduced, which, is made accurately to fill the place, by hammering the copper on the inside.
Muntz's metal is sometimes used instead of copper, and Muntz's metal air-pump rods are now as gen-
erally used as copper rods or iron rods covered with brass. Iron rods covered with brass are not to be
commended; they generally are wasted away where the bottom cone fits into the bucket-eye, and if the
casing be at all porous, the water will sometimes insinuate itself between the casing and the rod, and
eat away the iron. If iron rods covered with brass be used, the brass casing should come some distance
into the bucket-eye; the cutter should be of brass, and a brass washer should cover the under side of
the eye, so as to defend the end of the rod from the salt water. Rods of Muntz's metal are, probably.
on the whole to be preferred; and it is a good practice to put a nut on the top of the rod to secure it
more firmly in the cross-head eye. The part which fits into the cross-head eye should have more taper
when made of copper or brass than when made of iron; as if the taper be small, the rod may get staved
into the eye, whereby it will be 80 firmly fixed as to make its detachment a difficult operation. Me-
tallic packing has in some instances been employed in air-pump buckets, but its success has not been
such as to lead to its further adoption.
Sole-plate and condenser.-Every marine engine, of the side-lever kind, should be constructed with a
sole-plate; and we think it the best way that the condenser be cast upon the sole-plate. Engines un-
furnished with sole-plates, and with joints between the valve-casing and condenser below the level
of the keelsons, are extremely objectionable. Those joints, either from the working of the ship-the
movement of the cylinder or condenser-the deoxidizing effect of the oil spilt about the machinery-or
the combination of all these causes-will be sure, sooner or later, to become leaky; and it is almost im-
possible to remake or effectually stanch them. Messrs. Maudslay and Co., in their West India mail
packet engines, bolted the condenser to the under-side of the sole-plate; by which expedient the rust-
joints are preserved, in a great measure, from the action of the grease, and from any strain or vibration
consequent upon the yielding of the condenser or cylinder. Messrs. Miller and Co. adopted the same
arrangement of condenser, but cast the condenser upon the sole-plate.
There are very few of the engines made in Scotland in which the condenser is not cast upon the sole-
plate; and in almost all of them the greater part of the condenser is situated above the sole-plate, and
the main-centre passes through it. The height of the condenser, in this arrangement, has the advantage
of enabling the air-pump to drain it of water very effectually but the same object is accomplishable by
the use of a very large eduction-pipe immediately behind the valve-casing into which the injection wa-
ter is admitted, and which thus becomes, in effect, a tall condenser. This latter is the arrangement of
Messrs. Maudslay and Messrs. Miller. It has the advantage of leaving the space usually occupied above
the sole-plate by the condenser, free and unperplexed by any species of machinery except the main-
centre, which is supported by pillow-blocks resting or cast on the sole-plate.
The practice of passing the main-centre through the condenser, either with or without a pipe, is ob-
jectionable. A pipe is calculated to make the sides of the condenser crack by unequal contraction, and
the absence of a pipe endangers a leakage of air round the main-centre joint. The keys employed to
fix the main-centre will sometimes occasion trouble, from becoming loose; and, in some instances, we
have known a main-centre boss to be split, from the keys being driven too hard. In all cases the thick-
ness of metal requisite in the condenser sides for resisting the strain of the main-centre, will make the
sides more liable to crack, in consequence of being suddenly cooled. Upon the whole, the practice of
securing the main-centres by plummer-blocks appears greatly preferable: when the main-centre is
made to pass through the condenser, the hole should be bored out, and the main-centre ground in with
a little taper. It is the usual practice in engines which have the main-centre passing through the con-
denser, to set the hot well on the top of the condenser, and this is the arrangement in the engines of
which we have given the details. A part of the hot well is divided off, to serve as an eduction-passage
for the conveyance of the steam from the superior part of the valve-casing. By this arrangement there
is no danger of water running from the condenser back into the cylinder. Projections are cast in the
foot-valve passage for the reception of the foot-valve seat, by means of which it is keyed into its place;
and similar projections are cast in the mouth of the air-pump for the reception of the delivery-valve.
There does not appear to be any man-hole door to the condenser in this engine, which is a defect. It
would have been easy to make a man-hole in the curved nozzle leading from the air-pump to the hot
well: a door in that situation would have been easy of access from the hot well man-hole, and it would
have always been covered with water when the engine was at work, 80 that a leakage of air could not
have taken place. The injection nose-pipe runs across the condenser, near the mouth of the eduction-
pipe. A cock, by which water may be injected from the bilge, should the vessel spring a leak, is uni-
versally employed in marine engines, and is shown in the sectional drawing of the engines, dotted in.
This cock should never be furnished with a rose within the condenser, and should never be joined on to
the injection-pipe proceeding from the sea. We have known various cases in which a vessel has been
nearly lost from the internal roses of the bilge injection becoming choked up with refuse drawn out of
the bilge, and which, but for those roses, would have passed into the condenser and been delivered by
the air-pump without creating any obstruction.
Framing.-Cast-iron framing is now given up in marine engines, and malleable iron framing alone is
employed. It is a bad plan to attach the diagonal stay to the hot well, as is sometimes done, as the
working of the stay breaks the hot-well joint. It is a bad plan, too, to attach the framing to the sides
of the ship, as the working of the ship in a sea will strain and may break it. In iron steamers a plan
now prevails of running the deep beams before and abaft the crank-hatch (which are also made of iron)
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through the ship's side, joining the extremities of those beams by curved cross-beams, on which the shaft
plummer-blocks are made to rest. The paddle-wheel, by this plan, is overhung, and the whole of the
arms radiate from a triple centre. A very substantial framing may be made by adopting this arrange-
ment, and it is one which is applicable in the case of direct-action engines as well as in
those on the side-lever plan. The brasses of the paddle-shaft plummer-blocks should not
1421.
be made with fitting strips on the backs, but the whole of their exterior should be planed,
and the interior of the plummer-blocks should also be planed for their reception. Brasses
fitted with fitting strips soon wear slack sideways. Octagonal bottom brasses are not so
good as those which are square, as they cannot be lined up so conveniently if the shaft
gets out of truth. Square-bottom brasses, with flanges, as shown in Fig. 1421, we have
found preferable to any other variety.
Side-lever.-The drawing we have given of the side-lever will sufficiently explain its general form and
dimensions. In some of the more recent side-lever engines, the side-levers are made of malleable iron,
each lever being composed of two plates, set on edge, the length of the bearings apart from each other.
The studs in the side-lever should be steeled, and should be of larger dimensions than is necessary for
strength; as if they wear oval, they are likely to burst the side-rod or cross-tail straps, when the brasses
are tightened up. Unless the main-centre journals be made spheroidal, there should always be large
collars on the main-centre, against which the side-levers may press, so as to prevent lateral play; and
the washers on the main-centre ends should be capable of being tightened up against the brasses of the
side-lever eye. Without this precaution, the engines will jerk most disagreeably sideways in a sea-way
when the brasses come to be at all worn.
Cross-heads and tails, side and connecting-rods.-The parallel motion, it will be remarked in the
drawings of details, is attached to the cross-head; but parallel motions are now falling into disfavor, and
guides are taking their place. The side-rod eye is fitted with a conical bush, with a spiral cut in it, so
that it may be tightened upon the cross-head journal by means of a washer drawn in by a screw. In
some cases the side-rod eye is fitted with an octagonal brass, tightened by a cutter beneath the under
portion; and in other cases the brass is round, and the upper portion is pressed down by means of a
screw, which is made hollow, and serves also as an oil-cup. The upper piece is such as would require
to be cut out of the brass, in order to permit the journal to come out without being shifted on end and
the sliding joints of the bush are rebated, to prevent end-play. In the manufacture of brasses of this
kind the pieces are first fitted and soldered together; they are then bored and turned; and finally the
soldering is loosened by the application of heat. The cross-tail butts are generally ground on to their
places, and the end of the cross-tail riveted over on them, a round steel pin being afterwards intro-
duced, half into the cross-tail and half into the butt. In some cases, however, they are put on hot, as
practised in the case of cranks; and in the specimen before us a washer is substituted for the riveting
of the end. In all cases in which an eye is put on hot against a collar, the eye should be recessed for
the reception of a small portion of the collar, as the eye in contracting sideways will leave a space
between the collar and the eye, which, by this means, will not be discernible. The connecting-rod is
made with a strap to embrace the crank-pin, as is the usual practice. Connecting-ro made in this way
should always have a malleable iron cap above the upper brass, instead of having the cap and upper
brass made in a piece. If the crank-pin heats, the brass cap will probably be cracked, and cases might
be mentioned in which vessels have been nearly lost from such an occurrence.
Cranks, eccentrics, shafts, and paddles.-The cranks and shafts of marine engines are now always
made of wrought-iron. The crank is shrunk on the shaft hot, and a strong square key is then driven in
at the part nearest the web, so as to obviate the weakening of the eye. The crank-pin is fixed in the
intermediate crank, and is loose in the eye of the paddle-crank, which is fitted with a bush, upon which
the rounded end of the crank-pin bears. The end of the crank-pin, fitting into the eye of the inter-
mediate crank. is made conical, and is drawn into its place by a cutter passing through both pin and
eye. The rounded end of the pin enables the paddle-shaft to fall at the outer end, as it always does,
without breaking the pin. In some cases a drag-link is used instead of the rounded pin, but drag-links
are not now much in fashion. A very good method of fixing the crank-pin into the eye consists in the
application of a strong washer over the crank-eye, with a hole in the centre, through which a stout bolt
passes tapped into the pin. The washer is indented a little into the crank-eye, 80 as to obviate any
tendency to move laterally. This plan is unattended with any more trouble than if the pin were riveted
in, and it admits of the pin being taken out by merely unscrewing the bolt of the washer. The end of
the pin inserted in the loose eye is of course made spheroidal, 80 as to permit the outer end of the shaft
to drop a little, without breaking the pin. The pin is steeled on both sides of this spheroidal part, and
bears against two dovetailed steel plates. The plate situate on the backing side was, in the case of the
Don Juan, tightened by means of a screw passing through the crank-eye. The web of the crank was
made thicker and narrower than usual, the intention of the makers being that the web should be capable
of resisting the twist occasioned by the overhang of the crank-pin more effectually than is done in the
case of cranks whose shape is regulated by the supposition that the crank-pin does not overhang at all.
There is more plausibility than soundness in this reasoning; the fact being, that the strength given for
the single purpose of overcoming the leverage, is more than sufficient to withstand the twist. The
crank-pin must be fitted very accurately into the crank-eye, else it will be very liable to be broken.
The crank-pin should always be larger in diameter than is necessary for strength, for the purpose of
keeping the journal from heating. The dimensions given in our tables will be found to answer very well,
and they are slightly in excess of the common proportions.
We may here set down a few remarks about paddle-wheels, which cannot well be severed from the
subject of the engine. The best plan of making the centres is with square eyes, and each centre should
be secured in its place by means of eight thick keys. The shaft should be burred up against the heads
of these keys with a chisel, so as to prevent the keys from coming back of their own accord. If the keys
are wanted to be driven back this burr must be cut off, and the keys, if made thick and of the right
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taper, may then be started without difficulty. The shaft must of course be forged with square pro-
jections on it, 80 as to be suitable for the application of centres with square eyes. Messra. Maudslay
& Co. bore out their paddle-centres and turn a seat for them on the shaft, afterwards fixing them on the
shaft with a single key. The plan is objectionable for two reasons-it is insecure when new, and when
old is irremoveable. One of the West India mail vessels, by Messrs. Maudslay, was almost disabled
from this cause on the first voyage, the key on the shaft having slackened, and the centre having conse-
quently turned round; and in some of the older vessels by the same makers, lately under repair at
Woolwich, the centres had to be broken off, for they could not be got off in any other way. With this
plan of centre we have often known the centres to shift: in one case the wheel on the weather side was
forced against the side of the ship, and the floats, in their revolution, cut deeply into the outside plank-
ing. The plan of making round bosses on the shaft, and fixing the centres with four keys, as shown in
our plates of details, is also objectionable on the ground of insecurity.
The general practice among the London engineers, is to fix the paddle-arms at the centre to a plate
by means of bolts, Fig. 1422, a projection being placed upon the plates on each side of the arm, to pre-
vent lateral motion. We have found this method to be inferior in durability to that adopted in the
Clyde, Fig. 1423, in which each arm is fitted into a socket by means of a cutter, a small hole being left
opposite to the end of each arm, whereby the arm may be forced back by a drift. A preferable way
would be to form the paddle-centre out of the arms themselves, by widening them at the head until
they touch one another, Fig. 1424, and then applying a boiler-plate upon one side, and riveting the
arms firmly to it. If this plan be adopted, it will be expedient to swell the tops of the uncovered side
at the part nearest the centre, 80 as to increase the length of bearing for the keys which secure the
centre to the shaft. In the manufacture of this centre the heads of the arms would first be forged, then
planed on the edges and fitted together on the plate. The holes would then be bored for the rivets,
temporary bolts fitted into them, and the key-seats cut and the ends of the arms pared in the slotting-
machine. Finally, the arms would be welded on to the heads, and the various parts of the wheel riveted
together.
1424.
1423.
1422.
Most of the London engineers join the paddle-arms to the outer ring, by means of bolts, but those
bolts, after a time, generally become slack sideways, and a constant working of the parts of the wheel
goes on in consequence. Some engineers form the part of the outer ring opposite the arm into a mortise,
Fig. 1425, and they wedge the arms tight in the hole by wedges driven in on each side. But the plan
is an expensive one, and not satisfactory, as the wedges work loose even though riveted over at the
point. The best mode is the plan for the most part practised in the Clyde, Fig. 1426, of making the arm
with a long T-head, and riveting the cross-piece to the outer ring with a number of rivets, not of the
largest size, which would weaken the outer ring too much. The best way of securing the inner rings to
arms is by means of lugs, Fig. 1427, welded on the arms, and to which the rings are riveted.
1425.
1420.
1427.
Paddle-floats are usually made either of elm or of pine; if of the former, the common thickness for
large sea-going vessels is about 21 inches; if of the latter, 3 inches. They should have plates on both
sides, else the paddle-arms will be very liable to cut into the wood, and the iron of the arms will be
rapidly wasted. When the floats have been fresh put on, they must be screwed up several times before
they come to a bearing. If this be not done, the bolts will be sure to get slack at sea, and all the floats
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ENGINES, DETAILS OF.
on the weather side may be washed off, as once occurred to the British Queen, on the next voyage after
the floats had been removed to allow the vessel to go into dock. It is a good plan to give the threads
of the paddle-blocks a nick with a chisel after the nut has been screwed up, which will prevent the nut
from turning back. The floats should not be notched out, to allow of their projection beyond the outer
ring; as, if the sides of the notch be in contact with the outer ring, the ring is soon eaten away in that
part, and the projecting part of the float, being unsupported, is liable to be broken off. It is usual to
put a steel plate at each end of the paddle-shaft, tightened with a key, to prevent end-play when the
vessel rolls, but the arrangement is precarious and insufficient. Messrs. Maudslay make their paddle-
shaft bearings with very large fillets in the corner, with the view of diminishing the evil; and Mr. R.
Napier causes the crank-eyes of both paddle and intermediate cranks to bear sideways against the
brasses of the plummer-blocks. It would be preferable to make the bearings of the crank-shafts
spheroidal, and, indeed, it would be an improvement if most of the bearings about the engine were
to be made in the same fashion. The spheroidal form would not only prevent end-play, but would
keep the oil from running out at the ends of the bearings. The loose end of the crank-pin should be
made not spheroidal, but consisting of a portion of a sphere, and a brass bush might then be fitted into
the crank-eye, that would completely encase the ball of the pin, and yet permit the outer end of the
paddle-shaft to fall without straining the pin, the bush being at the same time susceptible of a slight
end-motion. This arrangement is far preferable to that of making the pin bear upon a single point, as
is the common practice. There is an inconvenient amount of wear on the pin, which involves a back-
lash in the eye, and the point of contact sometimes heats and screeches, unless the eye be kept well
supplied with tallow.
Disengaging paddle-wheels.-Many plans have been contrived for disengaging the paddle-wheels of
steamers, so as to enable one paddle to be worked without the other, or both paddles to be thrown out
of geer, so as to revolve loosely when the vessel is under sail. The best of these expedients is that
represented in Figs. 1428 and 1429, where A is the paddle-shaft; B, a cast-iron disk keyed thereon; C,
1428.
1429.
c
B
B
a wrought-iron strap surrounding the disk, lined with brass; D, a brass cushion with a tightening key
for producing friction, by bringing the cushion in contact with the disk; F, the brass lining of the
wrought-iron strap, excepting that portion occupied by the cushion; fff, screws by which the brass
lining is held to the strap. A few blows of a hammer on the key D will connect or disconnect the
paddle-shaft, even when the engines are at full speed.
Messra. Maudslay's method of disconnecting is to shift the
1431.
shaft on end by suitable geer, until the crank-pin leaves the
crank-eye. Messrs. Miller's method is to put a clutch on the
shaft, which catches into the paddle-centre-the whole of the
a
three centres being combined into one diverging one, which
runs loose on the shaft. A method contrived by Mr. Grantham
1432.
is represented in Figs. 1430, 1431, and 1432, where A is a
moveable bush in the paddle-crank eye; B, the crank; C, a
di
screw for moving in or out the bush; D, crank-pin; E, slot in
b
b
the crank-eye to permit the pin to pass in the revolution of the
crank, except when the pin-bush is moved out to engage it
B
F, square head of screw C; G, H, the bush engaged with the
B
1430.
$
crank-pin. It is obvious that by screwing the bush out or in,
3
3
the crank-pin is either engaged with or disengaged from the
paddle. In Messrs. Seaward's engines a method of disen-
1
gaging almost identical with this is sometimes employed.
Eccentrics-The eccentrics of marine engines are always
put on in two pieces; they are almost always loose on the
:
shaft, and are always capable of backing. The manner in
which that shown in our plates of details is made, is a common one. The eccentric is loose upon the
shaft, and is furnished with a back balance and catches, and the halves are put together with rebated
joints, to keep them from separating laterally; and they are prevented from sliding out by round steel
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pins, each ground into both halves. Square keys would be preferable to round pins in this arrange-
ment, as the pins tend to wedge the jaws of the eccentric asunder. In some cases the halves of the
eccentric are bolted together by means of flanges. The eccentric-rod shown in the plates of details is
not a particularly neat one. The eccentric-rod of the Don Juan is represented in Fig. 1433, and that
1433.
form is now widely adopted It is expedient to cast an oil-cup on the eccentric-hoop, and where it is
practicable, a pan should be placed beneath the eccentric, for the reception of the oil-droppings. The
notch of the eccentric-rod, for the reception of the pin of the valve-shaft, is usually steeled, to prevent
inconvenient wear; for when the sides of the notch wear, the valve movement is not only disturbed, but
it is very difficult to throw the eccentric-rod out of geer. It is found to be preferable, however, to fit
this notch with a brass bush, Fig. 1434, for the wear is then less rapid, and it is an easy thing to replace
this bush with another when it becomes worn. The eccentric catches shown in the plates are the kind
usually employed, but catches of this kind sometimes break off at the first bolt-hole, and it is preferable
either to have a bolt in advance of the catch-face, as in Fig. 1435, or to have a hoop encircling the
shaft, with the catches welded on it, the hoop itself being fixed by bolts or a key. This hoop may
either be put on before the cranks in one piece, or afterwards in two pieces, as shown in Fig. 1436. The
1436.
1435.
1434.
expansion-cam is figured in the plate; it is put on the shaft in two pieces, which are fastened to each
other by means of four bolts passing through lugs, and is fixed to the shaft by keys. A roller at one
end of a bell-crank, which is connected with the expansion-valve, presses against the cam, so that the
motion of the lever will work the valve. The roller is kept against the cam by a weight on a lever
attached to the same shaft. If the cam were concentric with the shaft, the lever which presses upon it
would remain stationary, and also the expansion-valve; but by the projection upon the cam, the end of
the lever receives a reciprocating motion, which is communicated to the valve. The position of this
projection determines the point in relation to the stroke at which the valve is opened, and the extent of
the projection determines the duration of opening. The time at which the valve should begin to open is
the same under almost all circumstances; but the duration of its opening varies with the amount of
expansion desired. In order to obtain this variable expansion, there are several projections made upon
the cam, each of which gives a different degree or grade, as it is usually called, of expansion. These
grades begin at the same point on the cam, but are of different lengths, so that they would begin to
move the lever at the same time, but would differ in the time of returning it to its original position. The
change of expansion is effected by moving the roller on to the desired grade. There are seven different
grades in the West India steamers. The expansion-valve is of the kind used in the Cornish engines,
and known as the equilibrium valve. Of the valve-shafts and links, parallel-motion rods, and other
similar details, it is needless here to speak, as there is nothing of difficulty connected with those parts,
and the plates make their arrangement sufficiently intelligible.
Starting-geer.-The best starting geer is Stephenson's link motion, which will be described in our
remarks respecting details of locomotives. This combination obviates the necessity of throwing the
engines out of geer at all; and full speed ahead may be changed instantaneously into full speed astern,
and without stopping the engines. Messrs. Rennie have introduced this species of starting-geer into
the Samson and some other steam vessels with the most satisfactory results; and it appears likely to
become general, at least in valves where there is little lap. In our plates of details the valve is moved
by means of a lever, and the eccentric-rod is thrown out of geer by means of a pulley on the end of a
lever, which, when raised, forces the pulley against the under side of the rod and lifts it out of the
notch. The act of raising this pulley depresses another pulley on a lever fixed upon the same shaft, and
enables another rod in connection with the starting-handle to fall into geer, the intention being, that
when the eccentric-rod is in geer, the starting-handle shall be without motion, as its swinging would be
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inconvenient and dangerous if worked by the engine. This plan of preventing the starting-handle and
the eccentric-rod from being in geer at the same time has now come into general use. The method
adopted by Napier in the Precursor is a very elegant one: it consists in the use of an eccentric-stud for
supporting the lever which carries the roller; and the act of moving this lever, 80 as to enable the
eccentric-rod to fall into geer, draws back the pinion of the starting-shaft out of the sector, with which it
is engaged. Instead of a lever, the starting-shaft in this case is moved by a wheel similar to a steering
wheel of a ship.
Brine-pumps.-Pumps for changing the water in marine engine boilers, so as to prevent the salt
water from reaching an inconvenient degree of saturation, were first applied by Messrs. Boulton and
Watt to the City of Edinburgh steamer, and their use is now very general. In the engines of the Centaur,
represented in the plate of direct-action engines, the brine-pumps are set on each side of the feed-pump,
and are wrought with it off the air-pump cross-head. In some cases the feed water is sent into a vessel
called a refrigerator, through which the super-salted water proceeding from the boiler to the brine-pump
is conducted in a multitude of small pipes,-the intention of the arrangement being to economize heat
by communicating the heat of the super-salted water to the feed. But the amount of heat thus saved
is exceedingly unimportant, and the refrigerators are not only expensive to construct, but are very
liable to be choked up by deposite. They thus become a source of danger, as the engineer is led to
confide in an expedient which may deceive him, while he believes it to be in effective operation. The
valves of brine-pumps require to be loaded sufficiently to counteract the pressure of the steam, and of
the head of water in the boiler. If brine-pumps be used, it appears preferable to use them without the
refrigerator; they then become equivalent to a continuous blowing off, but the pipes are less liable to
choke, and there is no blowing off while the engines are at rest.
Sea-water contains about 1-33 its weight of salt, and its specific gravity is increased by boiling until
it contains 12-33 of salt, which is the point of saturation, and the water will not then hold more salt in
solution. As the water is more concentrated, it requires a higher temperature to make it boil. The
boiling point of sea-water which has 1-33 of salt, is 2132°; with 2-33, 214'4°; with 3-33, 215-5; with
4-33, 216-7°; with 5-33, 217.9°; with 6-33, 219°; with 7-33, 220.2°; with 8-33, 221.4°; with 9-38,
222.5°; with 10-33, 223.7°; with 11-83, 224'9° and saturated water 226°. These are the boiling
points in the open air in a steam boiler, where the pressure of steam is always above the pressure of
the atmosphere, the boiling points will be correspondingly higher, but with any uniform pressure of
steam in the boiler it is possible to make the thermometer an index of the saltness of the water. If
the water be maintained at a concentration of 4-33, or if about one-fourth of the water be with-
drawn from the boiler by the brine-pumps that is forced in by the feed-pumps, very little deposite will
collect within the boiler. The quantity of fuel wasted by blowing off this quantity of water, cannot,
it is clear, be considerable, and there should not be less blown
off. Of every 4 cubic feet of water entering the boiler from the
1437.
hot-well, 3 passes off in steam and 1 in brine. The temperature
of the hot-well being 100°, the heat imparted to the water to
raise it into steam, may be represented by 1112° X 3 = 3336,
while the heat contained in the brine is 112°, or rather less, the
specific heat of brine being less than that of fresh water, and
3336 ÷ 112 = so that about 1-29th of the heat passes out of
the super-salted water when large blowing off is practised. A
much larger quantity of heat than this goes to waste if there be
any material accumulation of scale upon the flues, and engineers
will therefore see that there is no economy in penurious blow-
ing off.
Pumps, cocks, and pipes.-In the plates of details the feed-
pump plunger is shown with a screw at the bottom, for the
extraction of the core, but it appears preferable to extract the
O
core out of a hole in the top, which may be adapted for the
reception of the pump-rod. There should be a considerable
clearance between the bottom of the plunger and the bottom of
the pump-chamber, as otherwise the bottom of the chamber may
be knocked out, should coal-dust or any other foreign substance
gain admission, as it probably would do, if there were any in-
jecting from the bilge. Messrs. Maudslay make the feed and
bilge pump plungers serve as guides to the air-pump cross-head,
the pump-rods being continued upwards and working through
eyes in the framing. We do not see any objection to this
arrangement, if the stuffing-boxes be made deep when separate
guide-rods are used with eyes in the cross-head, those eyes should
be fitted with stuffing-boxes, to diminish the wear, and the
guides should be made very strong, for the same reason. The
valves of the feed-pump are most conveniently arranged in a
chest, which may be attached in any accessible position to the
side of the hot-well. An arrangement of this kind is shown
in Fig. 1437. Of the two side nozzles, the lower one leads to
the pump and the upper one to the boiler. The pipe leading
to the pump is a suction-pipe when the plunger ascends, and a
forcing-pipe when the plunger descends. The plunger, in ascend-
ing, draws the water out of the hot-well through the lowest of the valves, and in descending, forces
it through the centre valve into the space above, which communicates with the feed-pipe. Should the
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feed-cock be shut, 80 as to prevent any feed-water from passing through it, the water will raise the top-
most valve, which is loaded to pressure considerably above the pressure of the steam, and escape into the
hot-well. This arrangement is neater and less expensive than that of having a separate loaded valve on
the feed-pipe, with an overflow through the ship's side, as is the more usual practice. Figs. 1438 and 1439
1439.
1438.
8
E
for
L
H
10
E
3.0
represent a double-acting deck feed-pump of a very complete and efficient construction. It is of the
plunger kind, which is preferable to that which operates by a piston. The air-vessel is furnished with
an escape-valve, to prevent the pump from being split should it be put in connection with the engine
when the cocks in the pipe leading to the boiler are closed, an accident which not unfrequently happens.
Fig. 1440 represents a four-way cock, the application of which enables the pump to
draw from the sea, from the boiler, or from the bilge, and the pump can deliver
1440.
either into the boiler or upon deck. This pump can be worked either by the engine
,
or by hand it is employed to feed the boilers when the engines are stationary, or to
pump the boilers out, after they are blown off as far as can be accomplished by the
steam. At other times it is useful for raising the water to wash the decks, to act as
a fire-engine in case of fire, and to pump out the ship if she springs a leak.
In most of the new vessels fitted with tubular boilers, small engines have been
introduced, to pump water into the boiler when the vessel stops under steam. Most
of these engines are furnished with a crank and fly-wheel, but that introduced by Messrs. Penn has no
fly-wheel, and is a very compact and elegant arrangement. The pump-piston and the steam-piston are
at different ends of the same rod, and, instead of the ordinary pump-valves, a slide-valve is introduced,
which is situated at the opposite end of the steam slide-rod. The slide-valves are pipe-valves, and are
moved by means of a tappet on the piston-rod. On another part of the same plate some views are
given of a self-acting feed apparatus, which consists of a small chest, placed upon the front of the boiler
at the level of the water-line, with ports, closed by a sliding-plate, communicating with the water in
the boiler and the steam above it. When these ports are opened the water rises to the same height in
the chest as in the boiler, and the ports are opened and shut by the small engine at every stroke of the
pump. While the pump is making its stroke the ports leading from the chest to the boiler are closed,
and if the chest be chiefly filled with steam, it will be compressed by the entering water, and the chest
will receive a charge of water, which, on the ports being opened, will flow into the boiler. But if there
be but little steam in the chest when the pump is making its stroke, or the chest be filled with water
from the rise of the water-level, the water discharged by the pump cannot gain admission, and it must
therefore escape overboard through the loaded valve. Thus, as the water-level rises, the chest takes
less water from the pump, and it takes more when the level falls, the effect of which in practice is to
maintain a uniform water-level in the boiler, however great the variations in the demand for steam. In
some steam vessels floats have been introduced to regulate the feed, but their action cannot be depended
on in agitated water, if applied after the common fashion. Floats would probably answer if placed in
a cylinder which communicated with the water in the boiler by means of small holes; and a disk of
metal might be attached to the end of a rod extending beneath the water-level, 80 as to resist irregular
movements from the motion of the ship, which would otherwise prevent the satisfactory action of the
apparatus.
This disk would be placed within the cylinder, and a short distance above it a fixed diaphragm might
extend across the cylinder, between which and the moveable disk or piston on the rod the water would
be compressed, in the event of any sudden disposition of the float to rise, such as might be created by
the sudden motions of the ship; whereas by the slow and gradual subsidence of the water-level from
evaporation, the water in the cylinder would be able to subside by gradually passing through the small
holes in the cylinder and disk. One objection to this plan is, that the small holes would be liable to be
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ENGINES, DETAILS OF.
closed up by deposite; and the preferable arrangement, probably, would be to place the float within
the boiler, guided, but without any cylinder, and to apply я small oil cylinder, such as is used for the
cataract of some pumping engines, to the end of the float-rod where it protrudes through the top of the
boiler. Such an arrangement would enable the float to resist suddenly acting forces, while any force
that was gradual and steadily operative would still produce its due effect.
The admission of the feed-water into the boiler is sometimes regulated by cocks, and sometimes by
spindle-valves, raised and lowered by a screw. Cocks are less liable to accident or derangement than
screw-valves, and in modern steam vessels are generally employed. The feed-water is usually con-
ducted from the feed-cock to a point near the bottom of the boiler, by means of an internal pipe,-the
object of the arrangement being to prevent the rising steam from being condensed by the entering
water. By being introduced near the bottom of the boiler, it comes into contact in the first place with
the bottoms of the furnaces and flues, and extracts heat from them, which could not be extracted by
water of a higher temperature, whereby a saving of fuel is accomplished. In some cases the feed-water
is introduced into a casing around the chimney, from whence it descends into the boiler. This plan
appears to be an expedient one when the boiler is short of heating surface, and more than a usual
quantity of heat ascends the chimney; but in well-proportioned boilers a water casing round the
chimney is superfluous. When a water casing is used, the boiler is usually fed by a head of water, the
feed-water being forced up into a small tank, from whence it descends into the boiler by the force of
gravity, while the surplus runs to waste, as in the feeding apparatus of land engines, represented in
Fig. 1439.
Blow-off cocks are generally placed some distance from the boiler, but they should always be placed
quite close to it, as there are no means of shutting off the water from the pipe between the blow-off
cock and the boiler, should fracture or leakage there arise. Every boiler must be furnished with a
blow-off cock of its own, independently of the main blow-off cock on the ship's sides, so that the boilers
may be blown off separately, and may be shut off from one another. The preferable arrangement
appears to be, to cast upon each blow-off cock a bend for attaching the cock to the bottom of the boiler,
and the plug should stand about an inch in advance of the front of the boiler, 80 that it may be removed
or reground with facility. The floor-plate covering the blow-off cock should have a cooming, a few
inches high, cast round a hole of sufficient diameter to admit a box-key to turn the plug, and to each
plug a box-key should be fitted with a collar, at the level of the top of the cooming, of sufficient
diameter to cover the hole and thickness of metal around it, and with the top of the key-spindle
supported by an eye attached to the boiler. These box-keys would not be shifted from one plug to
another, as at present, but each would remain in its place, and the engineer would only have to turn
them when he wanted to blow off the boilers. The present method of using the blow-off cocks is very
inconvenient. A small plate has to be removed to enable the box-key to be applied; coal sometimes is
lying upon the plate, which has to be removed, and coal-dust gets into the bilge in these continual
removals, which chokes the roses of the bilge-pumps. In dark nights and rough weather, the engineer
requires to feel the nick in the top of the plug, which is often filled with coal-dust and grease, before he
can assure himself whether the cock is open or shut, and the operation of turning the cocks is more
difficult when the spindle of the key is without support. These evils may be remedied by the arrange-
ment suggested. The spindle will require to be made with a hole or eye to admit a handle wherewith
to turn it round, and it would be an easy thing to make the stud supporting the top of the spindle of
such a form that the handle for turning the spindle could not be withdrawn when the cock was open.
The cock, therefore, could not be left open without the handle being left in its place, where it would
stand out from the boiler, incommode the firemen, and duly notify the neglect.
The general arrangement of the blow-off pipes is to put a main blow-off pipe beneath the floor-plates
across the ship at the end of the engines, and into this pipe lead a separate pipe, furnished with a cock,
from each boiler. The main blow-off cock, where it penetrates the ship's side, is furnished with a cock
and in modern steam vessels Kingston's valves are also used, which consist of a spindle or plate-valve
fitted to the exterior of the ship, 80 that if the internal pipe or cock breaks, the external valve will still
be operative. Some expedient of this kind is almost necessary, as the blow-off cocks require occasional
regrinding, and the sea cocks cannot be reground without putting the vessel into dock, except by the
use of Mr. Kingston's valves or some equivalent expedient. When old vessels are getting new sea
cocks applied, it may answer to make the old cocks serve the purpose of Kingston's valves, the new
cocks being applied between the old cocks and the blow-off pipes.
All the cocks about an engine should be provided with bottoms and stuffing-boxes, and reliance
should never be placed upon a single bolt passing through a bottom washer for keeping the plug in, in
the case of any cock communicating with the boiler, for a great pressure is thrown upon that bolt if the
pressure of the steam be high and the plug be made with much taper; and should the bolt break or
the threads strip, the plug will fly out, and persons standing near may be scalded to death,-an acci-
dent which has sometimes happened. In large cocks it appears the preferable plan to cast the bottoms
in; and the metal of which all the cocks about a marine engine are made should be of the same quality
as that used in the composition of the brasses, and should be without lead or other deteriorating mate-
rial. In some cases the bottoms of cocks are burnt in with hard solder, but this method cannot be de-
pended upon, as the solder is softened and wasted away by the hot salt-water, and in time the bottom
leaks or is forced out. The stuffing-boxes of cocks should be made of adequate depth, and the gland
should be secured by means of four strong copper bolts. The taper of blow-off cocks is an important
element in their construction; as if the taper be too great, the plugs will have a continual tendency to
rise, which, if the packing be slack, will enable grit to get between the faces; while, if the taper be too
little, the plug will be liable to jam, and a few times grinding will sink it so far through the shell, that
the water-ways will no longer correspond. One-eighth of an inch deviation from the perpendicular for
every inch in height is a common angle for the side of the cock, which corresponds with one quarter of
an inch difference of diameter in an inch of height; but one-third of an inch difference of diameter for
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every inch of height, is a preferable proportion. The bottom of the plug must be always kept a small
distance above the bottom of the shell, and an adequate surface must be left above and below the
water-way, to prevent leakage. Cocks formed according to these directions will be found to operate
satisfactorily in practice.
Gage-cocks are rarely made with stuffing-boxes, and are for the most part adorned with stalactites
of salt after a short period of service, in consequence of leakage. The water discharged from them, too,
disfigures the front of the boiler, and adds to the corrosion in the ash-pits. It would be preferable to
combine the gage cocks appertaining to each boiler into a single upright tube, connected suitably with
the boiler, and the water flowing from them could be directed downwards into a funnel tube communi-
cating with the bilge. The gage-cocks and also the glass tube-cocks should be furnished with stuffing-
boxes, and with bottoms, unless the water enters through the bottom of the plug. The glass gage-
tubes should always be fitted with a cock at each neck, communicating with the boiler, so that both the
water and steam may be shut off if the tube breaks. The gage-cocks frequently have pipes running up
within the boiler, to the end that a high-water level may be made consistent with an easily accessible
position of the gage-cocks themselves. With the glass tubes, however, this species of arrangement is
not possible, and the glass tubes must always be placed in the position of the water level, whether it
be high or low.
The sea injection-cocks are usually made in the same fashion as the sea blow-off cocks, and of about
the same size. The injection water is generally admitted to the condenser by means of a slide-valve,
but a cock is more easily opened, and has not any disposition to shut of its own accord. The sea injec-
tion-pipes should be put through the ship's side in advance of the paddles, so that the water drawn in
may not be injuriously charged with air. In some cases the suction-pipe of the deck-pump leads into
the injection-pipe; but it is preferable to put a pipe through the ship's side for the exclusive use of the
deck-pump, as is the general practice. The waste-water pipe, passing from the hot-well through the
vessel's side, is provided with a stop-valve, called the discharge-valve, which is usually made of the
spindle kind, so as to open when the water coming from the air-pump presses against it. In some cases
this valve is a sluice-valve, but the hot-well is then almost sure to be split if the engine be set on with-
out the valve having been opened. The opening of the waste-water pipe should always be above the
load water line, as it will otherwise be difficult to prevent leakage through the engine into the ship,
when the vessel is lying in harbor.
Boilers are now generally supplied with stop-valves, whereby one boiler may be thrown out of use
without impairing the efficacy of the remainder. These stop-valves are usually spindle valves of large
size, and they are for the most part set in a pipe which runs across the steam-chests connecting the
several boilers together. The spindles of these valves should project through stuffing-boxes in the
covers of the valve-chests, and they should be balanced by a weighted lever and kept in continual ac-
tion by the steam. If the valves be lifted up and be suffered to remain up, as is the usual practice, they
will become fixed by corrosion in that position, and it will be impossible after some time to shut them
on any emergency. These valves should always be easily accessible from the engine-room, and it ought
not to be necessary for the coal boxes to be empty to gain access to them. The safety-valves should
not be set on the common pipe connecting the boilers, but each boiler should have a safety-valve of its
own set direct upon the steam-chest, for if the stop-valve should jam, and the safety-valve be exterior
to it, the safety-valve cannot contribute any thing to save the boiler from explosion. Each boiler also
should have a distinct steam-gage and a distinct atmospheric valve, if atmospheric valves be applied at
all, but they scarcely appear to be necessary in the case of tubular boilers, which are capable of with-
standing the atmospheric pressure with impunity.
The pipes of marine engines should always be made of copper. Cast-iron blow-off pipes have in
some cases been employed, but they are liable to fracture, and are dangerous. Every pipe passing
through the ship's sides, and every pipe fixed at both ends and liable to be heated and cooled, should
be furnished with a faucet or expansion joint, and in the case of cast-iron pipes, the part of the pipe fit-
ting into the faucet should be turned. In the distribution of the faucets of the pipes exposed to pres-
sure, care must be taken that they be so placed that the parts of the pipe cannot be forced asunder by
the strain, as serious accidents have occurred from the neglect of this precaution. A faucet is usually
placed where the main steam-pipe joins the branch steam-pipes proceeding to the cylinders, and if those
branch steam-pipes are attached to the cylinders or valve-casings by means of faucets, the whole of the
branch steam-pipes may swivel round on these faucets and leave the main steam-pipe, which will then
discharge its full volume of steam into the engine room, an accident which could hardly fail to be at-
tended with the most disastrous consequences.
Where the pipes pierce the ship's side, they should be made tight, as follows:-The hole being cut, a
short piece of lead pipe with a broad flange at one end should be fitted into it, the place having been
previously smeared with white-lead, and the pipe should then be beaten on the inside until it comes
into close contact all round with the wood. A loose flange should then be slipped over the projecting
end of the lead pipe, to which it should be soldered, and the flanges should both be nailed to the timber
with scupper nails, white-lead having been previously spread underneath. This method of procedure
prevents the possibility of leakage down through the timbers, and all therefore that has to be guarded
against after this precaution, is to prevent leakage into the ship. To accomplish this object, let the
pipe which it is desired to attach be put through the leaden hawse, and let the space between the pipe
and the lead be packed with gasket and white-lead. The pipe must have a flange upon it to close the
hole in the ship's side; the packing must then be driven in from the outside and be kept down by
means of a gland secured with bolts passing through the ship's side. If the pipe is below the water-
line the gland must be of brass, but for the waste-water pipe a cast-iron gland will answer. In the
case of iron vessels, it appears to be the best practice to attach a short iron nozzle, projecting inwards,
to the skin, for the attachment of every pipe below the water-line, as the copper or brass would waste
the iron of the skin if the attachment were made in the isual way.
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Parts of oscillating engines.-The most important parts of oscillating engines are the piston, the
piston-rod stuffing-box, the trunnions, and the attachment for the valve. The two former parts we have
already described; we shall here give the chief details of the two latter.
Fig. 1441 represents the valve attachment to the steam vessel the Trident, constructed by Messrs.
Boulton and Watt, cylinder 70% inches diameter, and 5 feet stroke, and reckoned at 350-horse power.
The eccentric rod is attached to the stud a, which is fixed to the centre of a plate forming part of a
frame which is guided vertically by means of the guide-rod b, and by the columns of the engine at c c.
d is the end of the valve lever which is moved up and down by the frame, whatever position in the arc
the end of the lever may occupy in consequence of the oscillation of the cylinder. e is a rack whereby
the frame may be moved up or down by means of a shaft at A B, when the eccentric rod is not in geer,
and at the end of the shaft a wheel is situated for starting the engine. The curved groove in which the
end of the valve lever moves is part of a circle, but it is not swept from the centre of the trunnion when
the valve is at half-stroke, but with a radius equal to the distance of the centre of the valve-shaft from
the centre of the trunnion, when the cylinder is perpendicular. Messrs. Penn do not form the curve in
this way, but sweep it from the centre of the trunnion when the valve is at half-stroke; and although
the same motion of the valve is not thus obtained as when there is no oscillation, the difference is very
slight, and is moreover considered to be a better motion than if no disturbance had taken place. It
appears to us that the use of a curve might be dispensed with altogether by observing a suitable ad-
justment of the eccentric; the effect would probably be to increase slightly the side pressure on the
piston-rod, but the increase would be altogether inappreciable in the case of equilibrated valves which
may be wrought with an inconsiderable exercise of force.
b
1441.
1442.
SCALE.-1 inch=1 foot.
Fig. 1442 represents one of the trunnions of the Trident, which, instead of being cast upon the cylin-
der, as is the usual practice, are bolted on with twelve 11-inch bolts, and are strengthened by twelve
brackets, 1 inch thick, cast on the flanges of attachment. There is a projecting ring, it will be observed,
left upon the part which is to be bolted on, which is accurately fitted into the hole in the belt in order
to obviate slackness sideways. A rib 11 inch thick runs back from the hole on each side in the middle
of the belt, to tie the belt more effectually to the cylinder, and above and below the belt a feather runs
vertically 11 inch thick, and tapering in depth from the belt till it runs off to nothing on the cylinder
side.
The bearing part of the trunnion is 22 inches diameter, 7 inches long, and the metal is 21 inches
thick; the steam-pipe entering the trunnion is 1 inch thick, and the packing space between the pipe and
trunnion 11 inch wide. The gland for compressing the packing is usually put on in two pieces. The
pipe requires to be so made that it can be pushed in against the cylinder in order to accommodate its
outer attachment. It is not necessary to make provision at the outer end of the trunnion-pipe for the
falling of the trunnion by wear, as the wear is so small as to be of no practical moment. The thickness
of metal of the cylinder is 11 inch; the thickness of the top and bottom of the belt is 21 inches in the
wake of the trunnion, and 2 inches in other places. The diameter of the hole in the belt is 18 inches;
the internal diameter of the steam-pipe is 13 inches; and the diameter over the flange for the attach-
ment of the trunnion is 301 inches. The interior of the beit in the wake of the trunnion measures 29
inches deep and 41 inches wide. The crank-shaft bearings are 12 inches in diameter and 13 inches
long. The paddle-wheels are overhung, and the outer journal of the shaft is 14 inches diameter, and 14
inches long; the part on which the centre is fixed, from whence the arms diverge, being 16 inches diam-
eter, and 24 inches long. When the paddle is overhung, the shaft increases in size at the outer end, in-
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stead of diminishing as in other cases. The diameter of the wheels is 22 feet; the floats are 2 feet
broad and 9 feet long, and have a dip of 4 feet 7 inches from the load water-line, at which point the
vessel draws 11 feet of water. The crank-pin is 9 inches in diameter, and has a length of bearing for
the connecting rod of 14 inches. The diameter of the Trident's piston-rod is 71 inches; we think the
introduction of larger piston-rods than have yet been introduced in oscillating engines would be an im-
provement, and would add to the durability of the engines. Each cylinder measures 8 feet 1 inch
across from centre to centre of trunnion, and 11 feet 6 inches from the level of the trunnion to the level
of the shaft.
The position of the trunnion should be a little above the centre of gravity of the cylinder, 80 that it
will have no tendency to tilt over when the piston-rod is disengaged from the crank-pin, and very little
tendency at the same time when pushed over to resume the perpendicular. The plan of attaching a
weight to one side of the cylinder to balance the valve-casing is now discontinued in the best engines,
and two valves are employed which balance one another. These valves are placed one on each side of
the trunnion, so that they may both be wrought by the-same eccentric. If the curved eccentric frame
were discarded, the eccentric rod might be attached immediately to a cross-head, from the ends of which
the two valve-rods descended, and the intermediate geer at present used might thus be dispensed with.
Engines applied direct to the screw.-It requires but little penetration to foresee that the present spe-
cies of marine engine must be given up if the screw propeller gains a general introduction, for the
engines will in that case be coupled immediately to the screw-shaft, which, as it requires to revolve
much more quickly than a paddle-shaft, involves a greatly increased speed of piston. Small engines,
with the pistons moving at a quick speed, will exert the same power as large engines moving with a
slow speed; and small engines, by being applied to the screw-shaft direct, may be made to do the
work of large ones. This is a manifest advantage to steam navigation, as a vessel may be constructed
with very large power without being inconveniently burdened with the weight of the engines; and it is
also an advantage to the makers of engines, who will thus be enabled to produce a given power at a
less cost. The only impediment to the general introduction of this system lies in the difficulty of driving
the air-pump at a high speed without causing the valves to strike 80 hard as to wear themselves out
very quickly. The difficulty may be met by making the air-pump piston without valves, and opening
and shutting the foot valve passage by means of a slide-valve, the motion for working which is derived
from the eccentric-rod. The delivery valve must still be opened by the pressure of water in the
pump; but it may be made to consist of a piston valve with skewed ports of the usual form, and it
may be closed, or the piston be brought opposite to the ports by means of a pendulum weight at
the end of a lever moving outside. Most of the engines at present in course of construction for direct
application to the screw, are made with four cylinders lying horizontally with two cranks upon the screw
shaft, to which the connecting rods are attached, the connecting rods being joined to the top of the pis-
ton-rods, as in the Gorgon, or locomotive construction. Oscillating engines, laid at an angle of 45°, and
joined to a single crank on the shaft, have in some cases been employed; and we think this arrange-
ment is upon the whole the preferable one. The air-pump may be made double-acting, and may be
worked from the same crank-pin to which the piston-rods are attached; the pin, however, being made
eccentric in the part to which the air-pump rod is attached, in order to give the pump a shorter stroke
than the piston. The crank and crank-pin will, if this arrangement be adopted, be stronger if made in
the same piece, and the neck of the shaft from which the crank overhangs must be made stronger than
usual. If the air-pump be made double-acting, as appears to be the preferable practice, its diameter
may be very small, but the foot and delivery valve passages must be larger than usual in proportion to
the size of the pump. If a piston valve be adopted for the delivery valve, it will be expedient to
balance the valve by means of a counterweight, as is done in case of the steam-valve, adding then a
pendulum, or a short crank pulled into the vertical position by a rod loaded with a weight, the end of
the rod being suitably guided by a swivelling eye, in order to bring back the valve, or retain the piston
opposite the ports until the pressure comes on. It is clear that, if this arrangement be adopted, the
thrust of the shaft forwards, which in the case of the Rattler screw steamer is equivalent to a weight of
four tons, cannot be sustained by the end of the shaft and the best arrangement appears to be, to re-
ceive the thrust upon a collar on the shaft, which works within an oil cylinder,-oil being forced con-
tinually by a small pump worked by the engine between the end of the oil cy 'inder and the collar, until
the collar is forced back with a pressure equal to that of the forward thrust. It is not expedient, how-
ever, to trust to the oil alone; and, therefore, between the collar and the bottom of the oil cylinder, and
also between the collar and the top of the oil cylinder-so as to give security for backing-rollers car-
ried by rings, as in the case of the rollers of a swivel bridge, or railway turn-table, should be interposed.
These rollers should be as numerous as can be conveniently applied; they should each touch only in one
point; should be made narrow, and several of these narrow rollers should be set upon the same spindle,
so as to increase the quantity of the bearing surface. The collar and ends of the oil cylinder should
consist of plates of hardened steel, and the rollers should also be of hardened steel, and be all made of
exactly the same diameter. The oil cylinder would have to be supplied with a safety-valve on each
side of the collar, so that any surplus oil sent in by the pump would be able to escape into a small tank,
out of which the pump would draw. By these expedients, the thrust of the screw may be effectually
and satisfactorily counteracted. It appears expedient to tooth out the eye of the collar, and to make it
of sufficient length to serve as a coupling-box, the end of the shaft proceeding from the screw to the collar
being similarly toothed, and fixed fast into the collar; while the end of the shaft proceeding from the
collar to the engine is toothed in the same fashion, but so fitted as to slide endways in the collar. By
this arrangement, should the oil cylinder yield slightly, or the rollers wear, the engine framing will still
be preserved from the forward strain; the only effect of such accidents being to make the engine shaft
slip somewhat further into the collar. The edge of the collar would be furnished with cupped leathers
upon each side, of the same description as those used for the rams of hydraulic presses.
Centres and lengths of rods.-In fixing the positions of the centres, it appears to be the most conve-
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nient way to begin with the main centre. The height of the centre of the cross-head at half-stroke
above the plane of the main centre, is fixed by the drawing of the engine, which gives the distance from
the centre of cross-head centre at half-stroke, to the flange of the cylinder; and from thence it is easy to
find the perpendicular distance from the cylinder-flange to the plane of the main centre, merely by putting
a straight-edge along level, from the position of the main centre to the cylinder, and measuring from
the cylinder-flange down to it, raising or lowering the straight-edge until it rests at the proper measure-
ment. The main centre is in that plane, and the fore and aft position is to be found by plumbing up
from the centre line on the sole-plate. To find the paddle-shaft centre, plumb up from the centre line
marked on the edge of the sole-plate, and on this line lay off from the plane of the main centre the
length of the connecting rod, if that length be already fixed; or otherwise the height fixed in the draw-
ing of the paddle-shaft above the main centre. To fix the centre for the parallel-motion shaft, when the
parallel bars are connected with the cross-head, lay off on the plane of main centre the length of the
parallel bar from the centre of the cylinder, deduct the length of the radius crank, and plumb up for
the central line of motion shaft; lay off on this line, measuring from the plane of main centre, the length
of the side-rod; this gives the centre of parallel-motion shaft, when the radius-bars join the cross-head,
as is the preferable practice where parallel-motions are used. The length of the connecting rod is the
distance from the centre of the beam when level, or the plane of the main centre, to the centre of the
paddle-shaft. The length of the side-rods is the distance from the centre line of the beam when level,
to the centre of the cross-head when the piston is at half-stroke. The length of the radius-rods of the
parallel motion is the distance from the point of attachment on the cross-head or side-rod, when the pis-
ton is at half-stroke, to the extremity of the radius-crank, when the crank is horizontal; or, in engines
with the parallel motion attached to the cross-head, it is the distance from the centre of the pin of the
radius-crank, when horizontal to the centre of the cylinder.
How to set the parallel motion.-In marine engines, having fixed the centre of the parallel-motion
shaft in the manner just described, it only remains to put the parts together when the motion is attached
to the cross-head; but when the motion is attached to the side-rod, the end of the parallel bar must not
move in a perpendicular line, but in an arc, the versed sine of which bears the same ratio to that of the
side-lever that the distance from the top of the side-rod to the point of attachment bears to the total
length of the side-rod.
The parallel motion when put in its place should be tested by raising and lowering the piston by
means of the crane: first set the beams level, and shift in or out the motion-shaft, plummer-blocks, or
bearings, until the piston-rod is upright. Then move the piston to the two extremes of its motion: if at
both ends the cross-head is thrown too much out, the stud in the beam to which the motion side-rod is
attached is too far out, and must be shifted nearer to the main centre: if at the extremities the cross-
head is thrown too far in, the stud in the beam is not out far enough. If the cross-head be thrown in
at the one end and out equally at the other, the fault is in the motion side-rod, which must be length-
ened or shortened to remedy the defect.
How to set the slide-valves.-The first thing is to ascertain whether the eccentric-rod is of the right
length. To determine this, put the valve in the middle of its stroke, 80 that both ports are covered
equally, and fix it in that position. Next, turn round the eccentric on the shaft until the eccentric-rod
has reached the furthest point of its travel from the shaft, and square up from the side of the eccentric-
pin a line upon the rod. Turn round the eccentric again until the eccentric-rod reaches the end of its
travel towards the shaft, and square up another line on the rod from the other side of the pin. If the
eccentric notch be equally distant from the lines thus marked upon the eccentric-rod, the rod is of the
right length; but if the notch be too far down upon it, the rod requires to be shortened; and if too far
up, to be lengthened-in each case to an extent equal to the deviation of the notch from the central
line. Thus, if on trial, the notch be found to be half an inch nearer to the lower than to the upper line,
the notch will require to be shifted up a quarter of an inch, to place it midway between the lines; and
to do this, the rod must be shortened a quarter of an inch; whereas, if the notch be half an inch nearer
the upper than the under line, the rod will require to be lengthened a quarter of an inch, and so on in all
other proportions.
The right length for the eccentric-rod having been thus obtained, and the rod having been adjusted
thereto, the next step is to set the crank perpendicular. In a workshop this is easily done by a plumb-
line, but in a steam-vessel recourse must be had to another method. Find on the sole-plate, or cylin-
der-mouth if a direct action engine, the transverse centre line answering to the centre of the shaft. De-
scribe on the large eye of the crank a circle of the size of the crank-pin, and lay off in a fore and aft
direction from the transverse centre line on cylinder-mouth or sole-plate, a distance equal to the radius
or half diameter of the crank-pin. Stretch a line from the point thus marked off to the edge of the
circle described on the large eye of the crank, and turn round the paddle-wheels until the crank-pin just
touches the stretched line-the crank will then be perpendicular, and may be set by this method either
on top or bottom centre.
The crank having been set in a perpendicular position while the valve is set and fixed with the
amount of lead it is intended to give, the eccentric has only to be turned round upon the shaft until the
notch comes opposite to the pin and the rod falls into geer, to determine the right position of the eccen-
tric on the shaft. The situation of the eccentric may then be marked upon the shaft, and the catches
fitted on in the usual way. The valve may first be set for going ahead, and may then be set for going
astern,-shifting round the eccentric to the opposite side of the shaft until the rod again falls into geer.
The position answerable to going ahead in some engines will be that answerable to going astern in
others, depending on the way in which the engines are placed, the arrangement of the levers, and the
kind of valve employed. It is necessary to recollect that it is the catches which drive the eccentric,
and not the eccentric the catches, mistakes having sometimes arisen from forgetfulness of this condition.
It is impossible to give any general rule for finding the length of the valve levers or the throw of the
valve. In most engines, however, the travel of the valve is twice the depth of the port, and the throw
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of the eccentric is equal to the travel of the valve, so that motion is neither gained nor lost by the levers.
In engines which do not operate expansively, the depth of the valve face is equal to the depth of the
port; but all modern engines have a certain amount of lap or cover on the steam side; and some on
the eduction side also. In the Thames and Medway steamers by Messrs. Maudslay, the travel of the
valve is 16 inches, and the length of valve lever 81 inches; depth of port 6 inches; length of port 26
inches; distance from upper edge of upper port to under edge of under port, 8 feet 91 inches; and dis-
tance between extreme edges of valve faces, 8 feet 91 inches; so that instead of there being cover upon
the eduction side, the valve is one-eighth of an inch short at each end, and will not cover the ports in
any position. In some engines the upper face is made narrower than the under face. In Messrs.
Maudslay's 50-horse power engines, the breadth of the port is 3 inches, and its length 15 inches; the
breadth of the lower valve face is 5 inches, and of the upper one, 43 inches. In the 48-inch cylinders
of the same makers, the size of port is 34 inches by 18 inches; in the 54-inch cylinders the size of port
is 20 inches by 4 inches; the valve faces, 8 inches, and 71 inches broad; and the length of the travel 11
inches. Other makers adopt different modes of setting the valves-we believe with little difference in
the efficiency of the engine. We must refer the reader to the investigations and rules we have already
given respecting alide-valves, as the best guide we can furnish for fixing the lap, lead, and other ele-
ments, in the absence of a uniformity of practice.
How to put the engines into a steamship.-First, measure across from the inside of paddle-bearers to
the centre of the ship, to make sure that the central line, running in a fore and aft direction on the deck
or beams, usually drawn by the carpenter, is really in the centre; and if it is not, make a fore and aft
line or mark that is in the centre. Stretch a line across between the paddle-bearers in the direction of
the shaft: to this line in the centre of the ship where the fore and aft mark has been made, apply a
square with arms six or eight feet long, and bring a line, stretched perpendicularly from the deck to the
keelson, accurately to the edge of the square; the lower point of the line where it touches the keelson
will then be immediately beneath the mark made on the deck. If this point does not come in the
centre of the keelson, it will be better to shift it a little, so as to bring it to the centre, altering the mark
on the deck correspondingly, provided either paddle-shaft will admit of this being done-one of the
paddle-brackets being packed behind with wood, to give it an additional projection from the side of the
paddle-bearer. Continue the line fore and aft upon the keelson as nearly as can be judged in the centre
of the ship; stretch another line fore and aft through the mark upon the deck, and look it out of winding
with the line upon the keelson. Fix upon any two points equally distant from the centre, in the line
stretched transversely in the direction of the shaft; and from those points as centres, and with any con-
venient radius, sweep across the fore and aft line to see that the two are at right angles; and if not,
shift the transverse line a little to make them 80. From the transverse line next let fall a line upon
each outside keelson, bringing the edge of the square to the line, the other edge resting on the keelson.
A point will thus be got on each outside keelson perpendicularly beneath the transverse line running in
the direction of the shaft, and a line drawn between those two points will be directly below the shaft.
To this line the line of the shaft marked on the sole-plate has to be brought, care being taken at the
same time, that the right distance is preserved between the fore and aft line upon the sole-plate, and
the fore and aft line on the central keelson. Before any part of the machinery is put in, the keelsons
should be dubbed fair and straight, and be looked out of winding by means of two straight-edges. The
art of placing engines in a ship is more a piece of plain common sense than any other feat in engineer-
ing; and every man of intelligence may easily settle a method of procedure for himself. Plumb-lines
and spirit-levels, it is obvious, cannot be employed on board a vessel; and the problem consists in so
placing the sole-plates, without these aids, that the paddle-shaft will not stand awry across the vessel,
nor be carried forward beyond its place by the framing shouldering up more than was expected. As a
plumb-line cannot be used, recourse must be had to a square; and it will signify nothing at what angle
with the deck the keelsons run, so long as the line of the shaft across the keelsons is squared down from
the shaft centre. The sole-plates being fixed, there is no difficulty in setting the other parts of the
engine in their proper places upon them. The paddle-wheels must be hung from the top of the paddle-
box, to enable the shaft to be rove through them: and the cross-stays between the engines should be
fixed in when the vessel is afloat. To try whether the shafts are in a line, turn the paddle-wheels,
and try if the distance between the cranks is the same at the upper and under, and the two horizontal
centres; if not, move the end of the paddle-shaft up or down, or backwards or forwards, until the distance
between the cranks at all the four centres is the same.
Miscellaneous remarks respecting marine-engines.-The cylinders should be felted, and then cased
with wood that has been baked until it will shrink no longer. The steam-pipes should be cased in the
same way, and the boilers should be felted, and then covered with sheet-lead, soldered at every joint.
The whole of the screws about the engine should be made according to a uniform system of threads, and
the nuts of the same sized bolts should also be of the same size, so that a single spanner will serve for
those nuts. The spanners intended for polished nuts should be close and single-ended, and they should
be themselves polished and case-hardened. and ranged in regular order on one of the engine-room bulk-
heads. A pair of brase-sheaved blocks for raising the cylinder cover, and another smaller pair for
raising the air-pump cover, should be provided; and a strong screw, with a large eye at the end, for
raising the paddle-wheel. Strong spanners should also be provided for the holding-down bolts, with
eyes at the end, to which a tackle may be applied; and a box-key for tightening down the bolts of the
paddle-shaft plummer-blocks through the crank-hatch. Tallow kettles are little needed if the pistons
and cylinder stuffing-boxes have metallic packings. Oil-cans and lamps should be ranged on a shelf in
separate stands, so that they cannot fall off when the vessel rolls. For every article of engine-room
furniture there should be a convenient and conspicuous place; and if there be any articles of spare
geer, they should be all kept in sight. Unless this be done, they are almost sure to be eaten up with
rust, as neglect generally follows their stowage in an unfrequented or inaccessible place.
In most steam-vessels a good deal of trouble is caused by the holding-down bolts, which are generally
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made of iron. Sometimes they go through the bottom of the ship, and at other times they merely go
through the keelson, a recess being made in the floor or timbers to admit of the introduction of a nut.
The iron, however, wears rapidly away in both cases, even though the bolts are tinned; and it has been
found the preferable method to make such of the bolts as pass through the bottom, or enter the bilge,
of Muntz's metal, or of copper. In side-lever engines four Muntz's metal bolts may be put through the
bottom at the crank end of the framing of each engine, four more at the main centre, and four more at
the cylinder, making twelve through bolts to each engine; and it is more convenient to make these
bolts with a nut at each end, as in that case the bolts may be dropped down from the inside; and the
necessity is obviated of putting the vessel on very high blocks in the dock, in order to give room to put
the bolts up from the bottom. The remainder of the holding-down bolts may be of iron; and may, by
means of a square nut, be screwed into the timber of the keelsons as wood screws, the upper part being
furnished with a nut, which may be screwed down upon the sole-plate, 80 soon as the wood screw
portion is in its place. If the cylinder be a fixed one, it should be bolted down to the sole-plate by as
many bolts as are employed to attach the cylinder-cover, and they should be of copper or brass, in any
situation that is not easily accessible. In well-formed bolts the spiral groove penetrates about one-
twelfth of the diameter of the cylinder, so that the diameter of the solid cylinder which remains is five-
sixths of the diameter over the thread. The strain to which iron may be safely subjected in machinery,
is one-fifteenth of its utmost strength, or 4000 pounds on the square inch, 80 that 2180 pounds may be
sustained by a screw an inch in diameter at the outside of the threads. The strength of the holding-
down bolts, therefore, may easily be computed, when the elevating force of the piston or main centre is
known, but it is expedient very much to exceed this strength in practice, on account of the elasticity of
the keelsons, the liability to corrosion, and other reasons.
A very useful species of oil-cup is now employed in a number of steam-vessels; and which, it is said,
accomplishes a considerable saving of oil, at the same time that it more effectually lubricates the
bearings. A ratchet-wheel is fixed upon a little shaft which passes through the side of the oil-cup, and
is put into slow revolution by a pendulum attached to it outside; and in revolving it lifts up little
buckets of oil and empties them down a funnel upon the centre of the bearing. Instead of buckets, a
few short pieces of wire are sometimes hung on the internal revolving wheel, the drops of oil which
adhere to them on rising from the liquid being deposited upon a high side set upon the funnel, and
which in their revolution the hanging wires touch. By this plan, however, the oil is not well supplied
at slow speeds, as the drops fall before the wires are in the proper position for feeding the journal.
Another lubricator consists of a cock or plug inserted in the neck of the oil-cup, and set in revolution by
a pendulum and ratchet-wheel, or any other means. There is a small cavity in one side of the plug,
which is filled with oil when that side is uppermost, and delivers the oil through the bottom-pipe when
it comes opposite to it. In some cases bearings heat from making a cruciform groove in the top brass
for the distribution of the oil, the effect of which is to leave the top of the bearings dry. In the case of
revolving journals, the plan of cutting a cruciform channel for the distribution of the oil does not do
much damage; but in other cases, as in beam-journals for instance, it is most injurious, and the brasses
cannot wear well wherever the plan IS pursued. The right way is to make a horizontal groove along
the brass where it meets the upper surface of the bearing, so that the oil may be all deposited on the
highest point of the journal, leaving the force of gravity to send it downwards. This channel should of
course stop short a small distance from each flange of the brass, otherwise the oil would run out at the
ends.
The paddle-shaft, where it passes through the vessel's side, is usually surrounded with a lead stuffing-
box, which will yield if the end of the shaft falls. This stuffing-box prevents leakage into the ship
from the paddle-wheels, but it is expedient as a further precaution to have a small tank on the ship's
side immediately beneath the stuffing-box, with a pipe leading down to the bilge to catch and conduct
away any water that may enter. The bearing at the outer end of the paddle-shaft is sometimes
supplied with tallow forced into a hole in the plummer-block cover, as in the case of water-wheels; but
for vessels intended to perform long voyages, it is preferable to have a pipe leading down to an oil-cup
above the journal, from the top of the paddle-box, through which pipe oil may at any time be supplied.
The eccentrics should be fitted with pans beneath them to catch the oil which falls. In vessels fitted
with Hall's condensers, the pistons and stuffing-boxes must be supplied with oil instead of tallow, as the
tallow congeals in the pipes of the condensers and chokes them up. The bolts for holding on the
paddle-floats should be made extra strong on account of the corrosion to which they are subject, and
the nuts should be made large and should be square, so that they may be effectually tightened up even
though the corners are worn away by corrosion. Paddle-floats, when consisting of more than one board,
should be bolted together edgewise by means of bolts running across their whole breadth; they should
not overhang the ring much at the outside of the wheel, else they will be very liable to be broken off
when the wheel strikes the water heavily. The aftermost paddle-beam should come as close as possible
to the wheel to prevent the spray from being carried up. The angular pieces or wales running from
the extremities of the paddle-beams to the back of the deck-houses, are best when fitted with iron
gratings, as wooden gratings are liable from their greater opposing surface to be carried away. The
brackets supporting the paddle-box steps should consist of circular pieces running round the paddle-box
from step to step, as when put on with isolated brackets the steps are liable to be carried away by the
sea. The funnel shrouds should consist of rope of the same dimensions as the shrouds of the mainmast,
but a few feet at the top should consist of chain, as rope close to the funnel would be burned.
It is very difficult to fix engines effectually which have once begun to work in the ship, for in time
even the surface of the keelsons on which the engines bear becomes worn uneven, and the engines
necessarily rock upon it. As a general rule, the bolts attaching the engine to the keelsons are too few
and of too large a diameter; it would be greatly preferable to have smaller bolts and more of them.
Twelve very strong brass or copper holding-down bolts going through the vessel's bottom are sufficient
for a side-lever engine, and supposing the vessel to be a wooden one; but there should be a large
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number of wood screws securing the sole-plate to the keelson, and a large number of bolts securing the
various parts of the engine to the sole-plate. In iron vessels, holding-down bolts passing through the
bottom are not expedient, and then the engine has merely to be secured to the iron plate of the keel-
sons, which are made hollow and admit of the most effectual attachment of the engine. Where the
framing is of cast-iron, it is very expedient to have one piece running across the end of the engines clear
of the connecting-rod, so as to bind the whole of the frames together, and a cross should extend horizon-
tally between the intermediate frames immediately beneath the paddle-shaft, so as to counteract the
disturbing action of the connecting-rods. At the cylinder jaw, if the frame works, the best expedient
appears to be the introduction of a number of steel tapered bolts, the holes having been previously
bored out; and if the flanges be thick enough, square keys may also be introduced, half into the one
flange and half into the other, 80 as to receive the strain. If the jaw cracks or breaks away, a malleable
iron hoop may be applied round the cylinder, and that will in all cases be the preferable expedient,
where from peculiarities of structure it can be as easily done as introducing bolts and keys. If the
engines rock very much in the vessel, and are defective in other respects, it will be the preferable plan
to take them out and thoroughly repair them, preparatory to their re-introduction; and the keelsons
will then have to be dubbed afresh, and the sole-plates fitted carefully to them. A common practice is
to let the sole-plates rest on the bolt-heads, and then to fit in wedges all round until the vacuity is
filled; but it is preferable to fit the plates down solid upon the wood, and such is the practice of the
best engineers.
Rust joints are not now much used in marine-engines, yet it is necessary that we should state how
they are made. One ounce of sal-ammoniac in powder is added to 18 ounces or a pound of borings of
cast-iron, and a sufficiency of water is added to wet the mixture thoroughly, which should be done some
hours before it is wanted for use. Some persons add about half an ounce of flowers of brimstone to the
above proportions, and a little sludge from the grindstone trough. This cement is caulked into the joints
with a caulking-iron, about three-quarters of an inch wide, and one-quarter of an inch thick; and after
the caulking is finished, the bolts of the joint may be tried to see if they cannot be further tightened.
The skin of the iron must in all cases be broken where a rust joint is made, and if the place be greasy,
the surface must be well rubbed over with nitric acid, and then washed with water until no grease
remains. The oil about engines has a tendency to damage rust joints by recovering the oxide. Cop-
persmiths stanch the edges of plates and the rivets by means of a cement formed of pounded quick-
lime and serum of blood, or white of egg. and in copper boilers such a substance may be useful in
stopping the impalpable leaks which sometimes occur, though Roman cement appears to be nearly as
effectual. It would be worth trying, however, whether the mixture would not prevent the internal
corrosion of boilers, if laid on as a paint. Wire gauze smeared with white or red lead and interposed
between surfaces made quite true, appears to be the best description of joint yet introduced, and has
now become identified with the practice of the best engineers.
Metals used in the construction of engines.-The general ambition in making cylinders is to make
them sound and hard; but it is expedient also to endeavor to make them tough, so as to approach as
nearly as possible to malleable iron. This may best be done by mixing in the furnace as many different
kinds of iron as possible; and it may be set down as a general rule in iron-founding, that the greater
the number of the kinds of iron entering into the composition of any casting, the denser and tougher it
will be. The constituent atoms of different kinds of iron appear to be of different sizes, and the mixture
of different kinds maintains the toughness which adds to the density and cohesion. Hot-blast iron was
at one time generally believed to be weaker than cold-blast, but it is now found to be the stronger of
the two. The cohesive strength of unmixed iron is not in proportion to its specific gravity; and its
elasticity and power to resist shocks appear to become greater as the specific gravity becomes less.
We give here the average results of a number of experiments made in Scotland upon the strength of
iron. The bars experimented on were one inch square and three feet long. Coltness iron (No. 1) bore
a weight of 636 pounds, and the same iron (No. 3) bore 649 pounds; Gartsherrie (No. 1) bore 633
pounds; Shott's, (No. 1,) 594 pounds; Wilsontown, (No. 1,) 706 pounds, and (No. 2, 718 pounds;
Pintwyn, (No. 1,) 681 pounds; Calder, (No. 3,) 765 pounds; Govan, (No. 3,) 645 pounds; Bumbow,
(No. 2,) 734 pounds. Mixed irons are found to be stronger. Coltness and Gartsherrie (No. 1) bore 842
pounds; Coltness, Castlehill, Shott's, and Gartsherrie, (No. 1,) 639 pounds; Coltness, (No. 1,) and Bum-
bow, (No. 2,) 677 pounds. A mixture consisting of 2 tons Pintwyn, (No. 1,) 4 tons Pintwyn, (No. 2,) 5
tons of Wilsontown, (No. 2,) 2 tons of Wilsontown, (No. 3,) 5 tons of Calder, (No. 2,) and 4 tons of
Calder, (No. 3,) bore 1,008 pounds; and a miscellaneous lot of old cast-iron of the cold-blast manufacture,
from Wilsontown, bore 1,500 pounds. Numbers 3 and 4 are the strongest irons in most cases: iron
remelted in a cupola is not 80 strong as when remelted in an air-furnace; and when run into green sand
it is not reckoned so strong as when run into dry sand or loam. The quality of the fuel, and even the
state of the weather, exerts an influence upon the quality of the iron. Smelting furnaces on the cold-
blast principle have long been known to yield better iron in winter than in summer, probably from the
existence of less moisture in the air; and it would probably be found to be an improvement in iron-
founding if the blast were to pass through a vessel containing muriate of lime, by which the moisture in
the air would be extracted. The secret of making fine-skinned castings lies in using plenty of black-
ening. In loam and dry sand castings the charcoal should be mixed with thick clay water, and applied
until it is an eighth of an inch thick, or more; the surface should then be very carefully smoothed or
sleeked, and if the metal has been judiciously mixed, and the mould thoroughly dried, the casting is
sure to be a fine one. Dry sand and loam castings should be as much as possible made in boxes; the
moulds may thereby be more rapidly and more effectually dried, and better castings will be got, with a
less expense.
In the malleable iron work of engines scrap-iron has long been used, and considered preferable to
other kinds; but if the parts are to be case-hardened, as is now the usual practice, the use of scrap-iron
is to be reprehended, as it is almost sure to make the parts twist in the case-hardening process. In
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case-hardening, iron absorbs carbon, which causes it to swell: some kinds of iron have a greater capacity
for carbon than other kinds, and in case-hardening they will swell more; and any such unequal enlarge
ment in the constituent portions of a piece of iron will cause it to change its figure. In some instances
case-hardening has caused such a twisting of the parts of an engine, that they could not afterwards be
fitted together. It is preferable, therefore, to make such parts as are to be case-hardened to any
considerable depth of Lowmoor iron, which, being homogeneous, will absorb carbon equally, and will
not twist.
Piston-rods are now very generally made of steel, and are obtained of the requisite size and quality
from the rolling-mill. Steel is made almost exclusively from Dannemora iron: the bars are arranged
in a furnace about 14 feet long; a layer of charcoal is spread over the bottom, then a layer of bars, and
S0 on until about 10 tons of iron have been introduced. The top is covered with charcoal, over which is
a layer of sand, and above that a layer of slush from the grindstone trough, applied wet; the object of
which is entirely to exclude the air. The fire is then lighted, and in about a week the iron will have
increased in weight a one hundred and fiftieth part, and be found converted into blistered steel. These
bars may then be fagoted and tilted, so as to form steel articles of any size. In the operation of case-
hardening the same process is carried on as in converting iron into steel, but it is only continued for such
a time as to enable the charcoal to penetrate to a moderate depth. In our judgment all the malleable
iron parts of a marine steam-engine should be case-hardened, as they cannot then be 80 easily defaced,
by hammer marks or otherwise, and will be much less liable to rust. The more unwieldy portions may
be case-hardened by prussiate of potash, a salt made from animal substances, composed of two atoms of
carbon and one of nitrogen, and which operates on the same principle as in the case of case-hardening
by means of charcoal. The iron is heated in the fire to a dull-red heat, and the salt is either sprinkled
upon it or rubbed on in the lump, or the iron is rolled in the salt in powder; the iron is then returned to
the fire for a few minutes, and immersed in water. By some persons the salt is supposed to act
unequally, as if there were greasy spots upon the iron which the salt refused to touch, and the effect
under any circumstances is exceedingly superficial; nevertheless, upon all parts not exposed to wear, a
sufficient coating of steel may be obtained by this process. The most common plan of case-hardening
consists in inserting the articles among horn or leather cuttings, bone-dust, or animal charcoal, in an iron
box provided with a tight lid, which is then put into a furnace, and kept hot for a period answerable to
the depth of steel required. In some cases the plan pursued by the gunsmiths may be employed with
convenience. The article is inserted in a sheet-iron case, amid bone-dust, often not burned; the lid of
the box is tied on with wire, and the joint luted with clay, and the box is heated to redness as quickly
as possible, and kept half an hour at a uniform heat. Its contents are then suddenly immersed in cold
water. The carbonaceous lining in the inside of old retorts is sometimes used in case-hardening with
good effect.
Steel is hardened by heating and cooling it suddenly, and softened by heating and cooling it slowly.
A thin blade of steel, if heated, and placed between the cold hammer and anvil, will become extremely
hard; whereas a thick piece of steel would not be made hard by such a mode of treatment. Mercury
has been proposed, instead of water, for hardening steel, but its use is not attended with sensible
advantage. Salt and water is also used, but the articles immersed in it are liable to rust, unless after-
wards steeped in lime-water. Water which has been long used for tempering is supposed to be
preferable to fresh water, and if the steel is harsh the chill is taken off the water. In the case of thin
edge-tools the water is sometimes covered with a film of oil, but it is a question whether plain water is
not preferable. The file-makers medicate the water they use for tempering, and the method of doing
so forms one of the secrets of the trade; but it appears probable that a little white arsenic is the chief
addition they make. A common practice with some steel articles is to make them in the first instance
as hard as possible, and then to soften them somewhat, or let them down, as it is called, by heating
them to a certain temperature, which is indicated by the color they assume. A pale straw-color, which
is indicative of a temperature of from 430° to 450°, is the color proper to tools for metal; a dark straw-
color, 470° to 490°, is that suitable for tools for wood and for screw-taps; a brown-yellow, verging to a
light purple, 500° to 530°, is the color suitable for hatchets and saws; and a dark blue, 550° to 600°,
is the color for springs. Steel dies may be tempered by heating them to the color of sealing-wax,
plunging them into naphtha heated to 200°, and so soon as ebullition ceases, plunging them into cold
water. It appears to be the prevailing opinion among experienced machinists, that for the great
majority of articles requiring to be tempered, plain cold water is the best agent, but that for small
elastic works oil is preferable. For letting down large tools, a red-hot muffle is a convenient instrument,
and is used in the Bank of England. Steel articles may be most effectually softened by exposing them
to a high heat, imbedded in a mixture of charcoal and chalk. Steel that has been spoiled by over-
heating may be recovered by heating and quenching in water four or five times, carrying each to a
somewhat less degree than the first excess, and finally the steel must be well hammered at a red heat,
continuing the hammering until the steel is nearly cold.
Copper and zinc seem to mix in all proportions, and every addition of zinc increases the fusibility.
The red color of copper slides into that of yellow brass at about 4 or 5 ounces to the pound, and
remains little altered to about 8 or 10 ounces; after this it becomes whiter, and when 32 ounces of zinc
are added to 16 of copper, the mixture has the brilliant silvery color of speculum metal, but with a
bluish tint. The alloys with zinc retain their malleability and ductility well, to about 8 or 10 ounces to
the pound; after this, the crystalline character begins to prevail. The alloy of 2 zinc and 1 copper
may be crumbled in a mortar when cold. The ordinary range of good yellow brass, that files and turns
well, is from about 41 to 9 ounces to the pound. Brazing solders may be stated in the order of their hard-
ness-3 parts copper and 1 part zinc, (very hard;) 8 parts brass and 1 part zinc, (hard; 6 parts brass,
1 part tin, and 1 part zinc, (soft.) A very common solder for iron, copper, and brass consists of nearly
equal parts of copper and zinc. Muntz's metal consists of 40 parts of zinc and 60 of copper. Any
proportions between the extremes of 50 zinc and 50 copper, and 37 zinc and 63 copper, will roll and
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work at the red heat, but 40 zinc to 60 copper are the proportions preferred. Bell-metal for large bells
consists of 41 ounces to 5 ounces of tin to the pound of copper. Tough brass for engine-work, 1} pound
tin, 11 pound zinc, and 10 pounds copper. Brass for heavy bearings, 21 ounces tin, } ounce zinc, and 1
pound copper. There is a great difference in the length of time brasses wear, as made by different
manufacturers, but the difference arises as much from a different quantity of surface as from a varying
composition of the metal. Brasses should always be made strong and thick, as when thin they collapse
upon the shaft, and increase the friction and the wear.
A lining metal for bushes has latterly been introduced in the bushes of locomotive axles, and
other machinery, composed of 1 pound of copper, 5 pounds regulus of antimony, and 50 pounds of
tin, or other similar proportions, the presence of the tin being the only material condition. The copper
is first melted, and the antimony is added, with a small portion of the tin, charcoal being strewed
over the metal in the crucible, to prevent oxidation. The bush or article to be lined having been cast
with a recess for the soft metal, is to be fitted to an iron, formed of the shape and size of the bearing or
journal, allowing a little in size for the shrinkage; drill a hole for the reception of the soft metal, say from 1
to t of an inch diameter; wash the parts not to be tinned with a clay wash, to prevent the adhesion of
the tin; wet the part to be turned with alcohol, and sprinkle fine sal ammoniac upon it; heat the article
till a fume arises from the ammonia, and immerse it in a kettle of Banca tin, care being taken to prevent
oxidation. When sufficiently tinned the bush should be soaked in water, to take off any particles of
ammonia that may remain upon it, as the ammonia would cause the metal to blow. Wash with fine
pipe-clay and dry, then heat the bush to the melting point of tin, wipe it clean, and pour in the metal,
giving it sufficient head as it cools; the bush should then be scoured with fine sand, to take off any dirt
that may remain upon it, and it is then fit for use. This metal wears for a longer time than ordinary
gun-metal, and its use is attended with very little friction. If the bearing heats, however, from the
stopping of the oil-hole, or otherwise, the metal will be melted out.
Proportion of Boulton and Watt's Wagon Boilers of various powers.
HORSES' POWER
2
3
4
6
8
10
12
14
16
18
20
30
45
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
ft. in.
Length
4 6
5 3
6 0
7 0
8 0
90
10 0
10 0
11 9
12 8
13 6
16 0
19 0
Breadth at water-line
3 2
34
3 6
3 9
4 0
43
46
4 9
5 0
5 2
5 4
5 6
6 0
Height
4 1
44
4 71
5 If
56
5 9f
60
6 2f
6 6
6 8
6 10
Height of water
2 6
2 8
2 10
3 3
36
38
39
3 10
4 0
4 1
4 2
4 9
5 6
Radius of crown
1 7
18
19
1 10f
2 0
2
23
2 41
26
2 7
28
2 9
3 0
Heating surface
30
0
38
0
46
0
64
0
83 0
100 0
118 0
138 0
156
0
176
0
201
0
297 0
438 0
Height of flue round
boiler
1 9
1 10
111
2 4
2 9
31
32
3 5
3 7
3 9
3 11
4 0
4 9
Width of flue round
boiler
0 9
0 9
0 10
0 10
1 0
0
1
1 1
1 2
1 2
1 2
1 4
1 3
Heating surface per
horse power
15
0
13 0
11 0
107
10-2
10 0
98
98
97
98
10 0
98
96
Capacity of steam
room in cuble feet
174
too
231
341
50
64
72
80
97
106
114.7
190
268
Contents of water in
cubic feet
37
40
56
76
103
134
102
205
238
270
299
282
342
The 30 and 45-horse power boilers contain internal flues.
A pound of coal raises about 9 pounds of water into steam, in the majority of good land-boilers; but
in some of the Cornish boilers, a pound of coal raises 12 pounds of water into steam, or a cwt. of coal
evaporates about 20 cubic feet of water. The weight of fuel burned on each square foot of grate-bars
varies very much in different boilers; in wagon boilers it is about 12 or 13 pounds, in Cornish boilers
from 31 to 4 pounds, and in locomotive boilers about 80 pounds. The number of square feet of heating
surface for each square foot of fire-grate, is in wagon boilers from 14 to 15 square feet; in Cornish
boilers, about 40 square feet; and in locomotive boilers, upwards of 70 square feet. Reckoning an
engine of 73 inches diameter of cylinder, and 7 feet length of stroke at 217-horse power, the area of fire-
grate in the most judiciously constructed marine flue-boilers, such as that of the Great Western, is .46
of a square foot,-the engine working expansively from one-third to one-fourth of the stroke. The
heating surface in this boiler is 88 square feet per horse power, if the horse power be reckoned by our
rule, so that the heating surface is 19 times the area of the grate surface; and if the consumption of
fuel be taken at 6 pounds per horse power per hour, as it was very nearly, there will be about 13
pounds of coal consumed per hour on each square foot of fire-grate. In the tubular boilers latterly
introduced into steam vessels, the proportions are somewhat different. The boilers of the Braganza,
reckoning the power of the engines at 289-horse power, have only 39 square feet of fire-grate per horse
power, while the heating surface is 11-98 square feet per horse power; but the grate surface, in this
case, admits of a ready increase by lengthening the bars. This is at the rate of 8071 square feet of
heating surface for one square foot of fire-grate; and if the consumption be taken at 6 pounds per horse
power per hour, there will be 15:38 pounds of coal consumed per hour on each square foot of fire-grate.
The grate surface per horse power in the tubular boilers of the Tagus is .38 square feet, and the heating
surface is 7.73 square feet, which is at the rate of 2039 square feet of heating surface per square foot
of grate. In the tubular boilers of the Sydenbam, the proportion is 21.64 square feet of heating surface
per foot of grate, but the proportion of grate per horse power is larger than in the Tagus. In the
tubular boilers of the Ocean steamer (232-horse power) the grate surface per horse power is 59 square
feet, the heating surface 13.48 square feet per horse power, which gives 22.84 square feet of heating
surface per square foot of grate. The consumption of coal per horse power per hour is 8.08 pounds,
which is at the rate of 14'71 pounds per square foot of fire-grate per hour; but if, for the sake of com-
paring it with the previous examples, the consumption be taken at 6 pounds per horse power per hour,
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as would be the case if the engine were worked more expansively, then the consumption of coal per
hour on each square foot of fire-grate would be 10-17 pounds. These particulars may be tabulated
thus :-
Heating surface
Vessels.
per nominal
Grate surface per
Heating surface
horse power.
per square foot
horse power.
of grate surface.
Great Western
Flue
boilers
88
.46
19
Braganza
Tubular
1198
39
3071
Tagus
Tubular
7.73
38
2039
Ocean
Tubular
13.48
59
22.84
Sydenham
Tubular
2164
Phoenix
Tubular
91
.44
20
The boilers of the Phoenix, by Messrs. Penn, are represented in one of our plates.
The amount of steam room in boilers varies very much. Wagon boilers of 2-horse power, it will be
observed, have about 8 cubic feet of steam room per horse power, and the proportion diminishes as the
size of the boiler is increased, until at 45-horse power the steam room is about 5 cubic feet per horse
power. In the tubular boilers of marine engines the proportion is less than this. The tubular boilers
of the Braganza have about 3.44 cubic feet of steam room per horse power those of the Ocean, 2.58
cubic feet, while some have as little as 1.79 cubic feet; but these last are addicted to priming. The
proportions of half a square foot of grate surface, 10} to 111 square feet of heating surface, and 3 cubic
feet of steam room per horse power, seem to answer very well for tubular boilers when the engines
work expansively through one-third or one-fourth of the stroke. In these estimations, the whole of the
tube surface is reckoned as effective surface.
The proper arrangement of heating surface in a boiler, 80 as to prevent the overheating of the plates,
is very important. Surfaces exposed to a high temperature should always be so made that the steam
may disengage itself easily from the metal; for if it be retained in contact with it for any considerable
time, the access of the water will be prevented, and the plate will become overheated in consequence.
The vertical sides of high furnaces are often greatly damaged from this cause the steam is retained
among the landings of the plates and other irregularities of surface, and the sides of the surface become
buckled and drawn, from the iron becoming overheated. It is very expedient, therefore, to make all
furnaces of marine or locomotive boilers wider at the bottom than at the top. The landings of the
plates should also be made so as to prevent the possibility of steam being retained in them. The after-
most tube-plate should be set at a slight angle to facilitate the liberation of the steam; and as the tubes
will thus be somewhat off the horizontal, any water which may escape by leakage will run into the
furnace, instead of incommoding the firemen by running out of the smoke-box doors.
Construction of boilers.-The whole of the shells of boilers intended to withstand any considerable
pressure, should be double riveted, with rivets 21 inches from centre to centre, the weakening effect of
double riveting being much less than that of single riveting. The furnaces above the line of the bars
should be of the best Lowmoor or Staffordshire scrap plates, three-eighths thick, and each furnace
above the bars should consist of three plates, one for the top and one for each side, the underseam of the
side-plates being beneath the level of the furnace-bars. The tube-plates of tubular boilers should be of
the best Lowmoor iron, seven-eighths to one inch thick; the shells should be of the best Thornycroft
S crown iron, or of Staffordshire iron, of good quality, and seven-sixteenths thick at the least. Angle
iron should not be used in any part of a boiler, as in the manufacture it becomes reedy, like wire, and
is apt to split in the direction of its length. It is a much safer dependence to bend the plates, if it be
carefully done, and without any more sharp turns than can be helped, but it is convenient to use a little
angle iron about the furnace mouths, which should be of the very first quality. The whole of the plates
of boilers should be punched with a double punch, one nipple of which enters the hole last punched,
while the other punches the hole: and it is very convenient to have the punching-press provided with a
travelling table, whereby the operation of punching and paring the edges of the plates is made a self-
acting one. The use of drifts and screw-jacks in putting the parts of boilers together, should not be
permitted. The rivets should be of the best Lowmoor iron, eleven-sixteenths in diameter. The whole
of the work should be caulked both inside and cutside, so far as it is accessible; the parts may then be
washed over with a solution of sal ammoniac, and the rivets and landings above water painted over
with a mixture of whiting and linseed-oil. It is very desirable that the space between the furnaces and
tubes of tubular boilers should be sufficiently large to enable a man or boy to get in. The bend joining
the top of the furnace at the after end with the bottom of the tube-plate, is very liable to get burnt
away and its repair will be most difficult, unless made accessible from the inside to hold on the rivets.
It appears expedient to shield this and another such exposed part, where the heat acts injuriously upon the
iron, by means of fire-blocks moulded to the place, and secured by nuts sunk into dovetailed recesses in
the substance of the block, which recesses are finally filled up with fire-clay. In new boilers even, such
an application is most expedient in situations in which injury to the iron, from the impact of flame, is
experienced or apprehended. The plate on the furnace side of the water-space at the end of the boiler
should be inclined considerably towards the tubes to facilitate the ascent of the steam and it appears
to be the preferable way to round off the top of the chamber leading from the furnace to the tubes. It
appears preferable, too, to zig-zag the tubes sideways, as a greater strength of iron is thus got between
the holes in the end-plates, without diminishing the facility of scaling the tubes, or introducing any
instrument down between them to keep the spaces clear.
Tubing and staying of boilers.-The tubes of boilers are most generally secured at the ends by means
of ferules driven tight into them, the holes in the end-plates being usually countersunk, and a corre-
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sponding projection being made on the ferules. The ferules next the furnace are best made of steel,
while, for the other ends, malleable iron ferules answer as well. The tool in which the ferules are made
consists of three pieces; one piece is set in the anvil, and consists of a flat plate with a nipple on it,
rising to half the depth of the ferule, and rounded at the corners; the next piece consists of a ring
furnished with a handle, and with its lower edge recessed slightly into the flat plate 80 as to steady it,
and this ring is larger in its internal diameter than the nipple by twice the thickness of the ferule; the
last piece consists of another nipple made like the first, but formed with a head like a punch. A small
hoop is formed by welding a piece of steel or iron, and is dropped into the space between the interior
of the ring and the lower nipple; the upper nipple is then forced down by striking the punch head with
a forge hammer, whereby the ferule is moulded to the right form: the parts are finally taken asunder,
whereby the ferule is liberated.
In brass tubes the use of ferules appears to be indispensable, but in the case of stout iron tubes, such
as Russell's patent boiler tube, they are unnecessary; and the best plan, when iron tubes are used,
appears to be to widen one end of the tube slightly, and to drive the tube in from the front of the boiler
into both tube-plates, the holes in the front plate being made one-sixteenth wider than those in the back
plate, and the tube being widened correspondingly. Before the tubes are driven in, the holes in the
tube-plates must be slightly countersunk, and the tubes must finally be carefully riveted in. It will
be expedient to screw a few of the tubes into the tube-plates instead of riveting them, 80 as to
serve as stays, and also as abutments to rivet the rest of the tubes against. The screwed tubes should
be left a little longer than the others; and thin nuts made of boiler-plate should be screwed upon the
projecting ends to prevent leakage, and add to the security of the staying. In fitting in the tubes in
this way, great care is necessary to make them perfectly tight; and it will be expedient to turn the
ends slightly in the lathe to give them a trifling taper, and make them all precisely of the same size.
In driving them in, each tube should not be driven home at once, as that will spring out the iron
between the holes, but they should be all fitted in first with the common chipping-hammer, and when
thus all equally fitted, they should be driven home by a heavy hammer or ram. The countersink in
the holes must be but slight, and must be filled rather by riveting up endways than by riveting over.
In some cases boilers are made with collars riveted on the tubes immediately behind the tube-plates,
but this plan is attended with the objection that a tube cannot be renewed without taking the boiler
asunder and with the still greater defect, that the ends of the tubes will be liable to get burned away
in consequence of the internal collar preventing the access of the water. Boilers formed on this plan,
therefore, will be found to become leaky at the ends of the tubes; and unless stayed, independently of
the tubes, the tube-plates will be forced asunder by the pressure of the steam.
To illustrate our views upon the staying of boilers by taking a particular case: suppose that it was
required to stay the boilers of the Phoenix in such a way as to be safe under a very high pressure. To
do this, it would be necessary to stay the sides of the furnaces to one another by three stays in the
direction of their height, and five or six stays in the direction of their length. The highest row of stays
would run along where the crown of the furnace joins the side, and the lowest where the bottom of the
furnace joins the side, the third being situated in an intermediate position, 80 as to be shielded as much
as possible by the furnace bars from the action of the heat. The bottom of each furnace should be
stayed to the bottom of the shell by two rows of stays, and the tops of the furnaces should be secured
by means of arched malleable iron bars, to which the plate would be stayed as in locomotive boilers.
These arches should touch the plates only at the points at which the stays go through, and their lower
edges should be sharpened away in order to facilitate the disengagement of the steam; they may be
joined together athwartships, or made in the same piece, and from the part opposite each water-space a
row of stays should run to the top of the boiler. To enable these stays to pass, a perpendicular row of
tubes must be left out opposite each water space, which will have the further advantage of enabling the
water to circulate with greater facility. The steam-chest should be stayed both fore and aft and across,
with stays pitched 18 inches or 2 feet apart; a row of athwartship stays should run horizontally across
immediately under, and another immediately above the tubes, and from the ends of the stays of the
superior, to the ends of those of the inferior row, vertical bars should ascend between the tubes and the
shell, to which the shell may be stayed while the sides of the water-space between the end of the
furnaces and the end of the boiler are stayed with stays of the same dimensions and pitch as those of
the furnaces. These stays may consist of 14-inch bolts of the best scrap-iron tapped through both
plates, and in the furnaces they should have thin nuts of boiler-plate on their ends; but where stay
bolts penetrate the boiler shell, they may have heads on the outside of the boiler. The whole of the
long stay bars should be fixed in their places, not with cutters, as is the common fashion, but with
rivets; they should be as it were built into the boiler, so that the safety of the boiler cannot be
endangered by the decay or accidental detachment of a cutter or pin. Where stays join on to the root
of the funnel, they must be continued through it by placing short stays in the inside; and wherever a
large perforation in the shell of a boiler occurs, from the application of a steam-chest or otherwise, a
sufficient number of stays should be put across the opening to make the strength as great as if there
were no perforation.
Respecting the strength of boilers, it is expedient to keep within a load of 8000 pounds upon the
square inch of iron in boilers in actual use. The breaking strain of good iron is about 60,000 pounds on
the square inch, but the best malleable iron will not bear a greater load than about 18,000 pounds on
the square inch, without permanent derangement of structure, or 17,800 pounds. Tredgold gives a rule
for determining the strength of cylinders, cylindrical boilers, and other such vessels, which gives propor-
tions not far from those which are advisable. It is this :-Multiply 2.54 times the internal diameter of
the cylinder by the greatest force of steam on a circular inch; divide by the tensile force the metal will
bear without permanent derangement of structure; the result is the thickness in inches. 'In practice,
the iron of boilers has sometimes to sustain a greater strain than what is indicated in this rule. The
utmost strain to which iron can be safely subjected in machinery, is 4000 pounds on the square inch, and
64
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this strain is approached in locomotive engines. A cylinder 12 inches diameter, with a piston-rod 11
inch diameter, and with steam of 80 pounds on the square inch, bears a tensile strain of 3766 pounds on
the square inch. Upon the iron of the boiler the strain is still greater, being about 5000 pounds on the
square inch. If the plate be five-sixteenths thick, it will require 32 inches in length of the boiler to make
a square inch of sectional area, and if the diameter be 39 inches, the separating force will be 39X32X
80=9984 pounds. But this strain is borne by a square inch of sectional area on each side of the boiler,
wherefore the strain on a single square inch of sectional area is half of this, or about 5000 pounds. This
takes no account of the support derived from the boiler ends, but in long boilers the support derived
from the ends is but small, and is not equivalent to the weakness caused by the rivet holes. A strain
at all approaching that upon locomotive boilers would be most unsafe in the case of marine boilers, on
account of the corrosion to which they are subject. All boilers should be proved with water when new,
to three or four times the pressure they are intended to carry, and they should be proved occasionally
by the hand-pump, when in use, to detect any weaknesses that corrosion may have created. In con-
nection with the strength of boilers, we may state that the Administration des Ponts et Chaussées," in
France, has fixed the following formula for the dimensions of safety-valves for stationary engines. d=
diameter in centimètres; c=the total heating surface in square mètres; n=the effective pressure in the
boiler in atmospheres;
d=2-6
n-0412
A mètre is 3.28 feet, and a centimètre is the hundredth part of a mètre, or 0328 of a foot. Every
marine boiler should be provided with a safety-valve, the action of which is independent of that of the
stop-valve, 80 that though the stop-valve becomes deranged, the safety-valve of that boiler will never-
theless act.
It is very desirable that a marine boiler should be fired from the one end only, a material saving of
room being thereby effected in the ship. In that case, too, there is no inducement to use more than one
funnel. Funnel plates are usually nine feet long and three-sixteenths thick, and if there be a platform
for coal over the boilers, it will be the best economy to make it of the same thickness, but the other
parts of the bunkers may be made of sheet-iron weighing 8 pounds to the square foot. The dampers
should not be the funnel, but in the top of the uptake, 80 that they may be closed if the funnel is
carried away. It is expedient to put two hoops upon the funnel for the attachment of the funnel
shrouds, 80 that the funnel will not be carried overboard should the bolts joining the lugs of one hoop
break, or should the funnel break across at the top hoop, as has sometimes happened from the corrosive
action of the steam escaping from the waste steam-pipe. A high angle-iron cooming should surround
the funnel, on the deck, outside of which should rise a sheet-iron casing, and this sheet-iron casing should
be riveted to the cooming or made quite tight thereto, so as to prevent the possibility of water leaking
down on top of the boiler. Over the casing, another short piece of casing riveted to the funnel should
descend for about a foot, so as to prevent the spray from entering between the casing and the funnel, and
thus getting down upon the boiler. The usual height of the funnel of sea-going steamers is from 40 to
50 feet.
Miscellaneous remarks about boilers.-All the rough nuts about a steam-vessel which require to be
screwed and unscrewed frequently, such as the bolts of the man-hole and mud-hole doors of the boiler,
should have large square nuts, and the bolts should be strong and have coarse threads. Hexagonal
nuts speedily become round in the hands of the firemen, by whom the mud-hole and man-hole doors are
generally taken off, and fine threads soon get stripped and overrun. It is much the safest way to put
on both mud-hole and man-hole doors from the inside, with cross-bars on the outside to keep them
closed. The plan sometimes followed, of putting on mud-hole doors from the outside, and securing them
by one or two bolts, is a practice we have already reprehended as full of danger, as, if the thread strips
or the bolt breaks, the door will fly off, and the boiling water rush out, scalding every one in the
vicinity. Mud-hole doors of this kind, even if they leak, cannot be screwed up to tighten them when
the steam is up, as there is a perpetual risk, in tightening the doors, of stripping the thread or breaking
the bolt.
Upon the corrosion of boilers.-The tops and steam-chests of boilers, and the bottoms of the ash-pits,
are the first parts to give way. The steam-chest wears chiefly from internal action; in some cases the
iron exfoliates in the form of a black oxide, which separates in flakes like the leaves of a book; while in
other cases the iron is, as it were, gouged away, and the heads of the rivets are worn off, as if by an
acid. It is most important that a remedy should be found for this evil, and it appears probable that by
painting the interior of the boiler with successive coats of Roman cement, or of some of the calcareous
cements which resist the action of water, the internal corrosion of the boiler might be prevented. Can-
vas soaked in liquid cement has been proposed, but it is questionable whether the canvas might not
on some occasion come off, and if it got into the mouth of the safety-valve orifice, it might cause the
boiler to burst. The ash-pits are worn away chiefly by the wetting of the ashes in the stoke-hole, and
it is expedient to apply shield-plates to those places when the boilers are made, which plates only will
be exposed to wear, and may be easily renewed, leaving the ash-pits untouched. The best method of
setting boilers appears to be to set them on a platform, and care must be taken that no projecting
copper bolts touch the boilers in any part, as they will be very likely to corrode the points of contact
into holes. The platform may consist of 3-inch planking, laid across the keelsons, nailed with iron nails,
and caulked and puttied like a deck. The surface may then be painted over with thin putty, and fore
and aft boards of about half the thickness may then be laid down-the heads of the nails being well
punched down. This platform must next be covered with mastic cement, and the cement must be
caulked beneath the boiler by means of wooden caulking tools, so as completely to fill every vacuity.
Coomings of wood must next be laid round the boiler, to confine the cement; and the space between the
coomings and the boiler must be caulked full of cement, and be smoothed off with a slope on the top so
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as to throw off any water that may chance to fall upon it. Many cements suitable for the setting of
boilers are sold ready made. The following is one of the compounds sometimes used :-To any given
weight of sand, or pulverized earthenware, add two-thirds of such given weight of Portland, Bath, or
any other similar stone, pulverized. To every five hundred and sixty pounds weight of these earths,
80 prepared, add forty pounds weight of litharge, and, with the last-mentioned given weights, com-
bine two pounds weight of pulverized glass or flint-stone. Then join to this mixture one pound
weight of minium and two pounds weight of gray oxide of lead. The composition being thus mixed,
pass the same through a wire sieve, or dressing-machine, of such a fineness as may be requisite for the
purpose intended, preferring a fine sieve, when the composition is to be used for works that require a
fine, smooth, or even surface. It is now a fine and dry powder, and may be kept open in bulk or in
casks for any length of time, without deterioration. When this composition is intended to be made into
cement, it is spread upon a board or platform, or mixed in a trough; and to every six hundred and five
pounds weight of the composition are added five gallons of vegetable oil, as linseed-oil, walnut-oil, or
pink-oil. The composition is then mixed in a similar way to mortar; it is afterwards subjected to a
gentle pressure by treading upon it, and this operation is continued until it acquires the appearance of
moistened sand. The cement should be used the same day the oil is added, otherwise it will fix or set
into a solid mass.
The large rivets sometimes used as stays for the shells of boilers, are objectionable, as the heads very
often come off; and if the fracture be between the boilers in a position not accessible from the outside, it
will be necessary to empty the faulty boiler of its water, in order to repair the defect. The sides of
furnaces should always be made to incline to each other in the manner already mentioned, 80 that the
crown is not 80 wide as the fire-bars, and it is a good arrangement to place the bars adjoining the sides
close against the sides throughout their length, so as to leave no air space in that situation. By this
arrangement the intensity of the heat acting immediately against the plates of the sides is diminished.
A crack in a plate is most conveniently closed, by boring several holes along its length and closing them
with rivets having large heads which cover over the defect. If a patch be applied to the top of a
furnace or flue, it is better to apply it from the inside of the boiler rather than from the flue, as in the
latter case a recess is left into which deposite falls, and a hole is likely then to be burnt again in the
same place. If the furnace mouth be contracted by bending in the sides of the furnaces, as is the
general practice, it is necessary to be very careful that scale does not accumulate in these corners, else
they will be very liable to be burnt into holes. The waste steam-pipe should be set into a faucet at
the bottom, instead of being constructed with a flange, as the neck of a flange will be broken by the
movement of the funnel when the vessel rolls. The waste steam-pipe should be as high as the funnel,
as, if lower, the waste steam continually striking against the funnel wears it out in that part very
rapidly. The pipe for conducting away the waste water from the top of the safety-valve, should lead
overboard, and not into the bilge, as the steam which passes through it when the steam is blowing off
is inconvenient if directed into the ship. Respecting fire bridges, the preferable practice, on the whole,
appears to be to construct them of brick rather than to make them water bridges, as with water bridges
there is often trouble from the cracking of the plates. If water bridges, however, be used, they should
be made with a great inclination in the breadth of the furnace, to facilitate the escape of the steam.
Flame bridges have been introduced into the furnace flues of steam-vessels on some occasions, consisting
of a pile of fire-brick, between which and the sides of the flue only a space of about three inches is left
for the flame and smoke to pass through, and the flame is spread in a sheet over the interior of the flue.
Where the flue is very large, the use of a flame bridge appears to be expedient; and in land boilers with
large internal tubes, its use has been attended with beneficial results, but in the majority of marine
boilers we believe that it will prove of but little service. Hanging bridges, consisting either of brick or
sheet-iron, descending from the top of the flue, are very beneficial in the majority of flue boilers, but are
inapplicable in the case of tubular boilers. A Venetian damper, however, or a perforated plate applied
at the end of the tubes, would probably produce the same effect, as it might be made to retain the heat
in the upper portion of the tubes by only opening it partially.
Locomotive engines.-General features of the boiler.-The boiler is the most important part of a loco-
motive-engine, and the useful effect of the machine depends in a great degree on the boiler being capable
of generating the requisite quantity of pure steam, without requiring the draught of air and flame
through the fire and tubes to be accelerated or forced excessively. The fire-box is that part of the
boiler in which the heat is generated and partially absorbed, the remaining absorption taking place in
the flue tubes, which convey the products of combustion from the fire, through the water, to the smoke-
box, whence they are dissipated in the atmosphere. Of course, the more nearly these products of com-
bustion, at their entrance into the chimney, are found to have been cooled down to the temperature of
the water in the boiler, the more economical in fuel the boiler will, cateris paribus, be. To obtain the
utmost economy in this way, the superficial surface of the tubes has been increased to the utmost extent,
by enlarging the diameter and increasing the number and size of the tubes. The boiler of Bury's
14-inch* engine contains 92 tubes of 21 inches external diameter, and 10 feet 6 inches long; the boiler
of Stephenson's 15-inch engine contains 150 tubes of 11 inch external diameter, and 13 feet 6 inches
long. It will therefore be seen that the superficial surface in Bury's tubes is, comparatively, rather
small, but yet the production of steam is found to be sufficiently copious, with a blast-pipe of rather
more than the average diameter on the other hand, notwithstanding its great surface, Stephenson's
boiler is found to require a smaller blast-pipe than usual It seems highly probable that the extra
intensity of blast requisite in the latter case consumes 80 much power to produce it, as completely to
countervail the economy of fuel consequent on the very complete abstraction of the heat, by the great
length of tubes in proportion to their diameter.
In an experiment tried by Mr. Stephenson, the heating surface of the fire-box, where the heat is re-
This dimension is the diameter of cylinder, by which dimension locomotivos are distinguished.
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ceived by radiation, was found to be more effectual than the tube surface, where the heat is received
by conduction, in the ratio of 1 to 3, and hence the heating surface of a locomotive is sometimes esti-
mated as the surface of the furnace plus one-third that of the tubes.
The shell, which is cylindrical, is attached to the smoke-box and fire-box by angle-iron; the end of
the shell next the smoke-box is closed entirely by the tube-plate, but at the smoke-box end the water
has free access quite round the internal fire-box, one side of which forms the tube-plate. The shell, ex-
ternal fire-box, and the smoke-box are always of iron, the thickness of plate being 5-16th in. in ordinary
boilers of 3 feet to 3 feet 4 in. in diameter, though in some cases it is 1 in.; the pitch of rivets is 1f in.,
and the diameter of rivets 11-16th in. The shell is sometimes made with flush joints, a band of iron
covering the joint attached by two rows of rivets. The boiler plates should have their fibres running
round the boiler instead of in the direction of its length, as the plate is somewhat stronger in that direc-
tion. The boiler is secured endwise by longitudinal stays, which are fastened by cutters to jaws at-
tached to the end plates.
The blast-pipe is the eduction-pipe diminished in area at the mouth to such a degree as to cause the
steam to issue with a great velocity, whereby a powerful draught through the fire is maintained by the
steam rushing up the chimney. The area of the mouth of the blast-pipe varies in different engines, but
an area of 1-22d of the area of the cylinder is a common proportion. A variable blast-pipe, the orifice
of which may be increased or diminished in area, is now much used. One arrangement for this purpose
consists of the application of a regulator plate at the top of the blast-pipe, with a hole through the centre
of the plate, through which the nozzle of the blast-pipe passes. When this regulator plate is closed, the
whole of the steam has to ascend through the central nozzle; but when the regulator is open, or partly
open, a part of the steam escapes through the holes in it. Another plan consists in the application of a
moveable plug within the blast-pipe, which may narrow the escape orifice to an annular space of small
area, the plug being raised or lowered by a lever and rod. Stephenson's method of contracting the
blast consists in making the nozzle of the pipe conical, and forming it to slide within the upright pipe,
whereby an annular space is left for the escape of the steam around the nozzle when the nozzle is
lowered.
The man-hole, or entrance into the boiler, consists of a circular or oval aperture of about 15 in. diam-
eter, placed by Bury at the summit of his dome, and by Stephenson in the front part, a few inches
above the cylindrical part of the boiler. The cover that closes this aperture in Bury's engine also con-
tains the safety-valve seats, thus simplifying the construction by preventing the necessity of an inde-
pendent aperture and cover for the safety-valves, as in Stephenson's engine, where the safety-valves'are
placed independently on the top of the dome. The steam-tight joint of the man-hole cover is made in
Bury's engine by a single thickness of canvas, smeared with red-lead; and the joint is not liable to be-
come defective or leaky, because the surfaces are turned true and smooth, both on the cover and its
seat. When these surfaces have not been made true in this manner, it becomes requisite to use a num-
ber of thicknesses of canvas, or other material, to form the joint; and the action of the steam soon
rotting away the soft substance, a leakage is caused through the joint, which makes repair indispensa-
ble. The small domes are of the same form as those used on the Grand Junction Railway, which are
cylindrical vessels of about 20 in. diameter, and 2 feet in height, with a semi-globular top, are gener-
ally made of plate-iron, about 1 in. thick, welded at the seam, and with the flange at the bottom turned
out of the same piece. In some cases, domes of this form have been constructed of cast-iron, about 1 in.
thick, but they have been found objectionable from their top weight, and they cannot be considered as
altogether safe from explosion.
The steam-whistle is generally placed upon the fire-box dome within conve-
1443.
nient reach of the engineer. It consists of a cock, Fig. 1443, opening by four side
holes into an annular chamber, whence the steam escapes through an annular
aperture about 1-64th in. in width, striking in its exit the edge of a bell, fixed by
a stem to the cock, whereby the sound is produced. The edge of this bell should
be about 1-32d of an inch thick, and should be exactly over the opening, so that
the issuing steam may impinge directly upon it. The metal should be of similar
composition to that of clock bells. The whistle is sometimes jointed by running
melted lead between its flange and the dome-plate; but it is better to fit the sur-
faces so truly together as to be steam-tight merely with the assistance of one
thickness of fine canvas coated with red-lead or cement, for lead will always
be found to decay by contact with high-pressure steam, making continual renova-
tion necessary. This remark equally applies to the other joints connected to the
shell of the boiler, such as the gage-tube, blow-off cocks, and feed-pipes.
To save the steam which is formed when the engine is stationary, a pipe is fitted
to the boiler which conveys the steam at such times to the tender, where it heats
the water and is itself condensed. This method of disposing of the steam is bene-
ficial in descending inclined planes, when more steam is formed than is required
for the use of the engine. A cock for emptying the boiler is usually fixed to the
bottom of the fire-box; this cock should not be placed at the front end of the fire-
box, as the foul water blown out of the boiler is thrown over the geering, which is
injured by the sand getting into the bearings.
Fire-box.-Iron fire-boxes have been extensively tried by Bury and others, and in cases where the
plate-iron of which they were formed has been of a peculiarly perfect texture, and not liable to laminate
or crack under the action of the heat, they have been found to answer exceedingly well, and not only to
be much cheaper than copper, but also to last at least twice as long before requiring renewal. If the
materials be very carefully selected, the use of iron fire-boxes will be found productive of economy, if
only used in situations where pure water is obtainable. The duration of ordinary copper fire-boxes de-
pends in a great measure upon the original texture of the copper, which ought to be rather coarse-grained
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than rich and soft, and also particularly free from irregularity of structure and lamination. Considera-
ble advantages have been found to arise from increasing the capacity of the fire-box, more especially its
depth, which ought to be such as to allow of the requisite quantity of coke being placed within it with-
out reaching above the mouths of the lower tubes, a fault which would cause the smaller pieces of coke
to enter and block up the tubes, to the manifest deterioration of the draught, and diminution of the
efficacy of the engine. The heating surface in the fire-box being of an extremely valuable and efficient
nature, and the extensive area of fire-bar surface being very conducive to freedom of draught, we are
induced to question whether the large square fire-box is not pro tanto preferable to the round one, which
must necessarily be very small, except on the 7-feet gage, in which case the round fire-box offers de-
cided advantages. The square fire-box is generally made of iron, i in. to I in. thick in every part ex-
cept the tube-plate, which has been from t in. to t in.; but experience has shown considerable advan-
tage in making the tube-plate i in. thick, as this great strength prevents the spaces between the tubes
from being compressed, and the tube holes rendered oval, in the processes of drifting and feruling the
tubes however, this evil will be found to exist, even with a i in. tube-plate, if the tube holes be placed
in too close contiguity, as has been found the case in several of Stephenson's engines; and, from practi-
cal observation, we find that t in. should be the minimum distance between any two tubes. The sides,
back, and front below the tubes, of the square fire-box, are stayed at intervals of 41 in. to 5 in. with
either copper or iron stays, screwed through the outer case into the fire-box, and securely riveted; but,
as the riveting within the fire-box is found to decay rapidly, from the action of the heat, Mr. Dewrance,
of the Liverpool and Manchester Railway, has adopted, with good results, stays formed with a large
square head, and screwed from within the fire-box outwards, the square head projecting 2 in. into the
flame. Iron stay-bolts for the fire-box are found to last nearly as long as copper, and, from their supe-
rior tenacity, are often considered preferable. Until lately, it had been supposed that round fire-boxes
possessed such advantages in point of strength over square ones, owing to their arched form, that they
were capable of resisting the pressure of the steam without the use of stays; but experience has shown
that, whatever be the shape, a fire-box must be stayed more or less to render it safe, for the shell of the
fire-box is liable to be wasted so much by the heat, that it is not safe to depend altogether upon the
strength its form confers, especially as the form will be changed if the boiler be suffered to become short
of water. In round fire-boxes, the sides near the crown part generally suffer most from waste: these
portions are now provided with stays by Messrs. Bury, Curtis, and Kennedy, who are the main sup-
porters of round fire-boxes ; and with this provision the round fire-boxes are necessarily the stronger.
The roofs of all fire-boxes require to be stayed by cross-bars; but the bars are required to be both
stronger and more numerous for the square fire-boxes, and should always be carefully made of wrought-
iron, and very carefully fitted before being bolted on. Stay-bars of cast-iron have been employed, on
account of their cheapness; but, having led several times to accidents from explosion, they are now dis-
carded. These bars are only in contact with the fire-box at the part around the rivets, and in all the
other parts they permit the access of the water below them. It is advisable to bring these bars to an
edge on the under side, 80 as to facilitate the escape of the steam. In Sharp and Robert's engines, the
fire-box is made of three plates; the tube-plate and front plate have their edges bent over, and to these
are attached a single plate which forms the crown, and two sides of the furnace. The interior fire-box
is joined at foot to the exterior by a Z-shaped iron, which forms the bottom of the water-space, and is
preferred, inasmuch as it leaves a wide water-space, and is easily cleaned. The outer and inner fire-
boxes are joined round the furnace door, which is double, to prevent inconvenient radiation. The
external fire-box has sometimes a semi-cylindrical top, joined by turning over the sides like an arch, and
sometimes a dome-shaped top.
The fire-bars have always been a source of much expense in the locomotive-engine, as they burn out
very rapidly, and have to be often renewed; from the rapid combustion going on over their upper
surfaces, they become heated intensely throughout, causing them to throw off scale, and to bend under
the weight of the fuel. The best remedy has been found to consist in making the bars very thin and
deep, so as to keep their lower edges exposed to a cooling draught of air, and to diminish the area of
metal conducting heat downwards from their heated upper edges. Thin fire-bars admit of being placed
nearer together than thick ones, thus offering no increased impediment to free draught, while preventing
the loss of small pieces of unburnt coke, which might otherwise drop through into the ash-box, and be
wasted. Fire-bars have given much satisfaction when made 4 inches deep, (parallel), and full I inch
thick on the upper edge and I inch on the lower edge. The frame carrying the fire-bars has often been
made capable of being dropped on the instant, with its fire-bars and fire, into the ash-box, or upon the
road, by means of catches drawn back by levers; but though the fire-bar frame is thus left unsupported,
very often it will not drop, and even cannot be forced down out of its place, owing to the clinkers and
tarry products of combustion forming an adhesive binding between its edge and the fire-box; it has ac-
cordingly been found best to support the fire-box frame permanently, and when any cause requires the
sudden withdrawal of the fire, to lift the fire-bars singly out of place, by means of the ordinary dart.
It is necessary to place the fire-bars with their upper surface about 3 inches higher than the bottom of
the water-spaces, which, by this means, will be allowed to contain quiescent water, ready to retain with-
out injury any deposite that subsides from the water, and the water-spaces should be periodically
cleansed, by means of the mud-holes placed opposite the edge of each water-space in the lower part of
the outer fire-box shell. These mud-holes are made water-tight by means of either a brass plug simply
screwed in and with a slight taper, or by a door applied with a soft packing on its face, and screwed up
with a bridge-piece and bolt, making the joint on the internal surface of the outer shell, the hole and
door being made sufficiently oval to enable the door to be introduced into the water-space. The latter
plan often gives rise to inconvenience, from the joint being found leaky when the steam is raised, ren-
dering it necessary to drop the fire, and empty the boiler, before it can be renewed. In some very large
square fire-boxes, such as those used on the Great Western Railway, a diaphragm, or divisional 4-inch
water-space ,has been placed across the middle of the fire-box, with the view of obtaining increased
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heating surface. This diaphragm has its lower edge (in which deposite takes place) made straight, and
about 2 inches below the general surface of the fire-bars, but its upper edge is of the form of an inverted
arch, in order to promote the free delivery of the steam generated within it into the steam-dome. The
sides of the fire-box, where the diaphragm is attached, are not cut away to form passages for the water
and steam, but are pierced with a series of circular holes, 3 inches in diameter, to permit a due circula-
tion without uselessly weakening the fire-box; but the uppermost hole of the series must be placed at
the highest point of the diaphragm, otherwise an accumulation of steam, and consequent injury at that
point, will ensue. The use of a diaphragm is found to be beneficial in the case of a very powerful en-
gine, provided its upper edge be made sufficiently low to admit of the tubes being conveniently drifted
over it, and to allow the dart to be used with facility, in dropping the front set of fire-bars.
The ash-box consists of a plate-iron tray, placed below the fire-box, to receive the burning ashes that
drop from betwixt the fire-bars. In the earlier locomotives, no ash-boxes being used, the red-hot ashes
were dispersed to a considerable distance by coming in contact with the wheels, and conflagrations were
often thereby originated. The ash-box should be as large as convenient, and not less than 10 inches
deep, otherwise it will materially impede the draught but if of ample dimensions, and closed at the
sides and back, it will increase the draught, particularly when running against a head wind, at which
time a strong draught is required. A hanging shutter to open or close the front of the ash-box forms a
good damper. The bottom of the ash-box is placed about 9 inches above the level of the rails, and
should on no account be nearer than 6 inches, otherwise the engine cannot pass safely over stones or
similar objects lying accidentally between the rails.
Tubes.-The tubes are generally formed of brass; the ferules by which they are secured are for the
most part made of steel at the furnace end, and of malleable iron at the smoke-box end, and the holes
in the tube-plates are tapered, 80 that the tubes bind them together. Great care should be taken in
securing the tubes, as any neglect will be productive of much inconvenience. The ferules are found to
be very injurious to freedom of draught, particularly in very small tubes; and to overcome this objec-
tion, the methods we have mentioned, and many others, have been tried for fastening the tubes in by
riveting over or screwing into the tube-plates; but hitherto no method, except that of internal tube-
rings, has been found to answer in the case of brass tubes; but we think it likely that, with wrought-
iron tubes, internal tube-rings will be ultimately abandoned. Stephenson has frequently adopted iron
tubes of late, in preference to brass, on the score of their greater cheapness and durability; and in some
cases, where unusual attention has been paid to them, and pure water used, they have been found to
answer very well. A common internal diameter of tubes is 18 in. If made very small, the tubes are
liable to be choked by pieces of coke, and the sectional area will be inconveniently contracted, while, if
made much larger, the heating surface will be unduly diminished. The number of tubes varies con-
siderably in different boilers in one species of locomotive in extensive use the number is 134, and the
pitch 21 in. Sufficient space is left below the tubes for deposite, that it may not be in contact with the
tubes and cause them to be burned: the extreme tube of the widest row is about the diameter of a
tube from the boiler shell. In the long-boiler engines of Stephenson, from the volume of water con-
tained in them, considerable time is required to get up the steam, even 80 much as three and a half
hours where the ordinary engines take two hours, and they require great care in firing and feeding to
prevent the steam running low.
Smoke-box and chimney.-The smoke-box door of many engines is hinged at the bottom, and is kept
shut by means of handles and catches; but the position of the door when open is in that case inconve-
nient, as it prevents ready access to the tubes. In some of Stephenson's engines, the smoke-box door
is in two leaves, which open like the doors of a house, overlapping at the centre, where they are closed
by a bar, and at top and bottom by handles and catches. This door admits of the easy examination of
the cylinders and valves. A small door is usually left near the bottom of the smoke-box, by which the
accumulated cinders may be removed. The bottom of the smoke-box should not be below the ash-pan,
or be much nearer the level of the rails than 18 inches, else the waste-water cocks of the cylinder
projecting through it, would be liable to injury from objects lying on the line. The smoke-box is lower
in freight engines than in passenger engines, on account of the driving wheels being smaller and, being
coupled with the other wheels, the cylinder has frequently to be inclined to let the moving parts work
clear of the front axle.
The chimney must not stand more than 14 feet high above the rails. The sectional area of the chim-
ney is about 1-10th of the area of fire-grate. The chimney is usually provided with a damper, similar
to the disk throttle-valve of an ordinary engine this is generally hung off the centre, and a hole is made
in it for the top of the blast-pipe, which projects through it when it is closed. Another damper has been
applied by Messrs. Rennie at the smoke-box end of the tubes, consisting of a sliding-plate perforated
with holes, which when opposite the ends of the tubes will give a free current. and may be made to
close them completely if required. Another kind of damper consists of an arrangement of thin bars
similarly disposed to the laths of a Venetian blind; the plates being so hinged, that when placed with
their edges to the tube-plate, they leave the flow of air through the tubes unimpeded, and when hanging
down they close up the tubes, or they partially close the tubes in any intermediate position. By either
of these arrangements, the hot air is retained for a longer period in contact with the tubes than if a simple
damper were used, as each tube is virtually furnished with a hanging bridge which keeps in the hottest
air and lets only the coldest flow out. An inconvenient degree of heat in the smoke-box is also pre-
vented. The smoke-box is usually made of t plate; the chimney of fth plate; the blast-pipe of fth
copper, and the steam-pipe of 3-16th copper.
Framing.-In some engines the side-frames consist of oak, with iron plates riveted on each side.
The guard-plates are in these cases of equal length, the frames being curved upwards to pass over the
driving-axle. Hard cast-iron blocks are riveted between the guard-plates, to serve as guides for the axle-
bushes. The side-frames are connected across at the ends, and cross-stays are introduced beneath the
boiler to stiffen the frames sidewise, and prevent the ends of the connecting or eccentric rods from fall-
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ing down, if they should be broken. The springs are of the ordinary carriage kind with plates, con-
nected at the centre, and allowed to slide on each other at their ends. The upper plate terminates in
two eyes, through each of which passes a pin, which also passes through the jaws of a bridle, con-
nected by a double-threaded screw to another bridle, which is jointed to the framing: the centre of
the spring rests on the axle-box. Sometimes the springs are placed between the guard-plates and be-
low the framing, which rests upon their extremities. One species of spring which has gained a con-
siderable introduction consists of a number of flat steel plates, with a piece of metal or other substance
interposed between them at the centre, leaving the ends standing apart.
A common mode of connecting the engine and tender, is by means of a rigid bar with an eye at
each end, through which pins are passed. Between the engine and tender, however, buffers should
always be interposed, as their presence contributes greatly to prevent oscillation and other irregular
motions of the engine. A bar is strongly attached to the front of the carriage on each side, and pro-
jects perpendicularly downwards to within a short distance of the rail, to clear away stones or other
obstructions that might occasion accidents if the engine ran over them. The axles bear only against
the tops of the axle boxes, which are generally of brass; but a plate extends beneath the bearing to
prevent sand from being thrown upon it. The upper part of the box in most engines has a reservoir of
oil, which is supplied to the journal by two tubes and siphon wicks. Stephenson uses cast-iron axle
boxes with brasses, and grease instead of oil, which is fed by the heat of the bearing melting the grease,
and causing it to flow down through a hole in the brass. All the engines with outside bearings have
inside bearings also; they are supported by longitudinal bars, which serve also in some cases to support
the piston guides: these bearings are sometimes made so as not to touch the shaft, unless in the event
of its breaking.
Steam-dome pipes and regulator.-The steam-dome, or separator, from the upper part of which the
supply of steam is obtained, is now generally placed over the fire-box; and in Bury's and Stephenson's
engines it forms a part of the external shell of the fire-box; whilst in the engines used on the Grand
Junction Railway, it consists of an independent cylindrical vessel, attached to the low roof of the fire-
box. Either plan, this latter or Bury's, is perfectly safe and strong, without the addition of stay-rods;
but Stephenson's dome presents a large extent of flat surface, from the roof of the internal fire-box up to
the arched roof of the external fire-box; and this flat surface requires to be powerfully stayed by angle-
irons and tension-rods. We remember an instance in which the accidental omission of one of the nu-
merous tension-rods led to the forcing out and partial explosion of the side of the fire-box, showing how
much depends on the circumstances of these rods, with their joints and pins, remaining sound and unin-
jured from corrosion or other source of injury or decay. In this respect the round fire-box, with its
dome, has the advantage of superior strength and safety. A large steam-dome is found to be the most
efficacious mode yet tried for preventing the evil of priming or damp steam; but no height of dome will
entirely prevent it if there be not space enough left above the tubes in the cylindrical part of the boiler
to allow the free passage of the steam along to the fire-box and dome, while an excessive height of dome
is also found to produce an unsteady motion of the engine, by causing the machine to be top-heavy. A
height of about 2 feet 6 inches above the cylindrical part of the boiler is found to give satisfactory re-
sults in practice, and to lead to the production of as pure steam as any greate. altitude could secure.
In some engines the steam is withdrawn from a dome placed at the smoke-box end of the boiler, into
which the steam-pipe rises. It is thought that the ebullition being less violent at this point, the steam
will thus be more effectually dried. The steam-pipes are made either of iron or copper; and of these,
iron best withstands the high temperature of the smoke-box and the impact of the cinders, but it is liable
to internal corrosion. The steam-pipe, after entering the smoke-box, divides into two branches, one
passing down each side of the smoke-box so as to leave a free space for cleaning the tubes, and also to
avoid as much as possible the impact of the hot air and cinders; but in some engines the steam-pipe
descends vertically, which is somewhat inconvenient in practice. The area of the steam-pipe is one-
sixth to one-eighth of the area of cylinder, and the branch steam-pipes are each about one-teuth of the
area of cylinder.
The admission of the steam from the boiler to the cylinders is regulated by a valve or regulator,
which is generally placed immediately above the internal fire-box, and is connected with two copper
pipes, one conducting steam from the highest point of the dome down to it, and the other conducting
the steam that has passed through it along the boiler to the upper part of the smoke-box. Regulators
may be divided into two sorts, viz., those with sliding-valves and steam-ports, and those with conical
valves and seats, of which the latter kind are the best. The former kind have for the most part hitherto
consisted of a circular valve and face, with radial apertures, the valve resembling the outstretched
wings of a butterfly, and being made to revolve on its central pivot, by connecting-links between its
outer edges or by a central spindle. In some of Stephenson's engines with variable expansion geer,
the regulator consists of a slide-valve covering a port on the top of the valve-chests. A rod passes
from this valve through the smoke-box below the boiler, and by means of a lever parallel to the start-
ing lever, is brought up to the engineer's reach. Cocks were at first used as regulators, but were given
up, as they were found liable to stick fast. A gridiron slide-valve has been used by Stephenson, which
consists of a perforated square plate moving upon a face with an equal number of holes. This plan
of a valve with a small movement gives a large area of opening. In Bury's engines a sort of coni-
cal plug is used, which is withdrawn by turning the handle in front of the fire-box; a spiral groove of
very large pitch is made in the valve-spindle, in which fits a pin fixed to the boiler, and by turning
the spindle an end motion is given to it which either shuts or opens the steam passage according
to the direction in which it is turned. The best regulator would probably be a valve of the equilibrium
description, such as is used in the Cornish engines.
Safety-valves and fusible plugs.-The safety-valves are placed upon the dome, in Bury's and Stephen-
son's engines; but it has been found much better to place them on the cylindrical part of the boiler, be-
cause when an engine commences to prime, the water projected from the blast-pipe generally causes an
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unusual generation of steam, which escapes at the safety-valve, and in its passage of course accumulates
and lifts the surface-water and foam at whatever point of the boiler the safety-valves are situated; thus
the farther they are placed from the steam-dome the better, as they will then diminish the evil of prim-
ing, which, if placed upon the steam-dome, they would only aggravate. Indeed, if the safety-valves
are properly situated, an engineman has the great advantage of being able to check or stop the priming
of the boiler on the instant, by causing his safety-valves to blow off strongly. It is requisite to place
the safety-valves upon a tubular pillar, of such altitude as to prevent the escaping cloud of steam from
obscuring the look-out of the engineman. Bury's 14-inch engine contains a pair of safety-valves of 21
inches diameter, exclusive of the mitre and Stephenson's 15-inch engine contains a pair of 4-inch diam-
eter. The latter dimension is preferable, as large safety-valves are much less liable to adhere to their
seats than small ones. Safety-valves require to be tested occasionally; and the best method consists
in attaching the valve joint-pin to one end of an ordinary pair of scales, when the overbalancing weight
at the reverse end will indicate the real pressure upon the valve, which exceeds the nominal pressure
by the weight and friction of the lever, with its joints and spring balance, and the adhesion of the valve
to its seat. To bring this adhesion to a minimum, it is a good plan to make the lip of the valve-seat
somewhat flatter than a mitre, that is, at a less angle than 45° with the horizon: 30° answers very
well.
The safety-valve is pressed down by means of a lever, and a screw at its extremity is attached to a
spiral spring balance. To find the pressure per square inch, multiply the weight indicated on the scale,
by the ratio of the two arms of the lever, and divide the product by the number of square inches in the
area of the valve; but to save the trouble of calculation, the
1444.
ratio of the arms of the lever is made so as to be expressed
by the number which represents the area of the valve, 80
that the weight marked on the balance is the pressure per
square inch upon the valve. Some allowance must be
made for the weight of the valve itself, and part of that of
the lever. It is expedient to put a stop upon the screw by
which the lever is screwed down or the tension of the spring
increased, so as to prevent the pressure from exceeding a
safe amount. Lock-up valves, which were intended as a
precaution against the recklessness or neglect of the en-
gineer, have fallen into disfavor, as from such valves being
inaccessible and seldom being required to act, they became
fixed in their seats; but it is an easy thing to make a valve
which can be raised, but cannot be forced down by the en-
gineer, and such valves are in general use in steam vessels.
In the engines of Cave, Hick, and Jackson, one of the valves
is permanently loaded a little above the usual pressure, and
enclosed in a chest it is usually made with bent, flat, steel
springs, pressing against one another, and guided by stand-
ards screwed to the valve-seat. One of these valves is
shown by Fig. 1444.
A plug of lead is usually fixed in the furnace crown, which melts if the boiler becomes short of wa-
ter, and gives notice of the danger. In some engines a cock is attached to the top of the steam-dome,
against which a small disk of fusible metal is retained by a ring of brass bolted to the cock, and which
is intended as an antidote to explosions. When the cock is opened, the steam has access to the under
side of the fusible plate, which when melted is forced through the small hole in the retaining plate; and
the engineer being thus warned of the undue pressure, can shut the cock and take measures to reduce
the pressure. This, however, is altogether a futile expedient, for the steam would be too much cooled
in passing through this cock and small pipe to melt the metal: and even if that defect were remedied,
the objections still remain, as applying to all fusible plugs, and the danger is increased by leading the
engineer to trust to a measure of safety that is inoperative in the hour of danger. Steam gages have
not been applied hitherto to locomotives, on account of the inconvenient height of the column of mer-
cury requisite to balance the steam. But it would be an easy thing to make a steam gage of moderate
dimensions, by making the tube, whether straight or siphon, of glass, closed at the top, so that the
mercury in its ascent would have to compress the air above it; and the graduations would be equal, or
nearly so, if the tube were made taper.
Cylinders and valves.-The cylinders are made of cast-iron, about three-quarters of an inch thick, and
should be of hard metal, 80 as to have but little tendency to wear oval from the weight and friction of
the piston. The ends of the cylinder are made about one inch thick, and both ends are very generally
made removable. At each end of the cylinder there is generally about half an inch of clearance. The
valve is invariably of the three-ported description it is made of brass, and is not pressed upon by the
valve-casing, as it is necessary in the absence of cylinder escape-valves that the steam-valve should
be capable of leaving the face to enable the steam or air shut within the cylinder to escape when the
train is carried on by its momentum, and also to afford an escape for the water carried over by the
steam when priming takes place. The operation of priming upon the cylinders and valves is very in-
jurious, as the grit and sediment then carried over with the steam wears the pistons, cylinders, and
valve faces very rapidly; so that if the water be sandy and the engine addicted to priming, the pistons
and valves may be worn out and the cylinders require re-boring in the course of a few months.
The valve-casing is sometimes cast on the cylinder: the face of the cylinder on which the valve works
is raised a little, so that any foreign matters deposited upon it may be pushed off to the less elevated
parts by the valve. The area of the steam-ports is in some cases one-ninth, and in others one-twelfth
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or one-thirteenth of the area of the cylinder; and the eduction one-sixth to one-eighth of the area of the
oylinder,-proportions which allow at mean speeds of twenty-five to thirty miles per hour, a pressure
little different from that of the steam in the steam pipes: for higher speeds the ports should be larger
in proportion. The valve casing is covered with a door, which can be removed to inspect the valves or
the cylinder face. Some valve casings have covers upon their front end as well as their top, which ad-
mits of the valve and valve bridle being more readily removed.
A cock is placed at each end of the cylinder to allow the water to be discharged which accumulates
there from priming and condensation. The four cocks of the two cylinders are connected, so that by
working a handle the whole are opened or shut at the same time. In Stephenson's engines with varia-
ble expansion, there is but one cock, which is on the bottom of the valve chest.
The valve lever is usually longer than the eccentric lever, to increase the travel of the valve. The
pins of the eccentric lever wear quickly. Stephenson puts a ferule of brass on these pins, which being
loose and acting as a roller, facilitates the throwing in and out of geer, and when worn can easily be
replaced; so that there need be no material derangement of the motion of the valve from play in this
situation. The starting lever travels between two iron segments, and can be fixed at the dead point or
for the forward or backward motions. This is done by a small catch or bell crank jointed to the bottom
of the handle at the end of the lever, and coming up by the side of the handle, but pressed out from it
by a spring. The smaller arm of this bell crank is jointed to a bolt which shoots into notches made in
one of the segments between which the lever moves. By pressing the bell crank against the handle of
the lever, the bolt is withdrawn, and the lever may be shifted to any other point; when the spring be-
ing released, the bolt flies into the nearest notch.
The pistons which consist of a single ring and tongue piece, or of two single rings set one above the
other so as to break joint, are preferable to those which consist of many pieces. In Stephenson's pistons
the screws are liable to work slack and the springs to break. The piston-rods are made of steel, the
diameter being from one-seventh to one-eighth of the diameter of the cylinder. They are tapered into
the piston, and secured there with a cutter. The top of the piston-rod is secured by a cutter into a
socket with jaws, through the holes of which a cross-head passes, which is embraced between the jaws
by the small end of the connecting rod, while the ends of the cross-head move in guides. Between the
piston-rod clutch and the guide blocks, the feed-pump rod joins the cross-head in some engines. The
guides are formed of steel plates attached to the framing, between which work the guide blocks, fixed
on the ends of the cross-head, and which have flanges bearing against the inner edges of the guides.
Steel or brass guides are better than iron ones. Stephenson and Hawthorn attach their guides at one
end to a cross-stay,-at the other to lugs upon the cylinder cover; and they are made stronger in the
middle than at the ends. Stout guide-rods of steel encircled by stuffing-boxes on the ends of the cross-
head would probably be found superior to any other arrangement. The stuffing-boxes might contain
conical bushes cut spirally, in addition to the packing; and a ring cut spirally might be sprung upon
the rod and fixed in advance of the stuffing-box with lateral play, to wipe the rod before entering the
stuffing-box, and prevent it from being scratched by the adhesion of dust.
Feed apparatus-The feed-pumps are made of brass, but the plungers are sometimes made of iron,
and are generally attached to the piston-rod cross-head, though in Stephenson's engines they are worked
by rods attached to eyes on the eccentric hoops. There is a ball valve be-
tween the pump and the tender, and two usually in the pipe leading from the
1445.
pump to the boiler, besides a cock close to the boiler, by which the pump may
be shut off from the boiler in the case of accident to the valves. The ball valves
are guided by four branches which rise vertically and join at top in a hemispher-
ical form, as shown in Fig. 1445. The shocks of the ball against this have in
some cases broken it after a week's work, from the top of the cage having been
made flat, and the branches not having had their junction at top properly filleted.
These valve guards are attached in different ways to the pipes; when one occurs
at the junction of two pieces of pipe it has a flange, which, along with the flanges
of the pipes and that of the valve seat, are held together by a union joint. It is
sometimes formed with a thread at the under end, and screwed into the pipe.
The balls are cast hollow, to lessen the shock as well as to save metal: in some
cases, where the feed-pump plunger has been attached to the crose-head, the
piston-rod has been bent by the strain; and that must in all cases occur if the
communication between the pump and boiler be closed when the engine is started,
and there be no escape valve for the water. Spindle valves have in some cases been used instead of
ball valves, but they are more subject to derangement. Slide valves might easily be applied, and
would probably be found preferable to either of the other expedients. The pipes connecting the ten-
der with the pumps should allow access to the valves and free motion to the engine and tender.
The feed-pipe of many engines enters the boiler near the bottom, and about the middle of its length.
In Stephenson's the water is let in at the smoke-box end of the boiler, a little below the water level.
By this means the heat is more effectually extracted from the escaping smoke but the arrangement is
of questionable applicability to engines of which the steam-dome and steam-pipe are at the smoke-box
end, as in that case the entering cold water would condense the steam.
To ascertain the height of water in the boiler, gage-cocks and glass tubes are provided, as in the case
of marine boilers. One of these glass gages is represented in Fig. 1446. The upward turn of pipe pro-
ceeding from the top of the tube in the interior of the boiler, is calculated to prevent the water from
boiling down through the tube, as it sometimes will do if the boiler be too full. The downward turn
of the tube at the lower end does not appear calculated to be of service. A small screw plug is placed
on each socket opposite the cock to enable a wire to be introduced, to clear the cock, should it become
choked. There are generally three gage-cocks attached to the boiler,-besides the glass tube,-the
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lowest of which should always run water, and the highest should always blow steam. If the water 08.
cillates inconveniently in the glass tube, the evil may be checked by partially closing the cocks.
Wheels.-The driving wheels are made large to increase the speed;
the bearing wheels also are easier on the road when large. In freight
1446.
engines the driving wheels are smaller than in passenger engines, and
are generally coupled together. Wheels are made in various ways;
they are frequently made with cast-iron naves, and with the spokes
and rim of wrought-iron. The spokes are forged out of flat bars with
T formed heads; these are arranged radially in the founder's mould,
whilst the cast-iron centre is poured around them; the ends of the T
heads are then welded together to constitute the periphery of the
wheel or inner tire, and little wedge-form pieces are inserted where
there is any deficiency of iron. In some cases the arms are hollow
though of wrought-iron, the tire of wrought-iron, and the nave of cast-
iron; and the spokes are turned where they are fitted into the nave,
and are secured in their sockets by means of cutters. Hawthorn
makes his wheels with cast-iron naves, and wrought-iron rims and
arms, but instead of welding the arms together, he makes palms on
their outer end, which are attached by rivets to the rim. These rivets,
however, unless very carefully formed, are apt to work loose; and we
think it would be an improvement if the palms were to be slightly
indented into the rim, in cases in which the palms do not meet one
another at the ends. When the rim is turned, it is ready for the tire,
which is now often made of steel. The materials for wheel tires are
first swaged separately, and then welded together under the heavy
hammer at the steel works, after which they are bent to the circle,
welded, and turned to certain gages. The tire is now heated to red-
ness in a circular furnace; during the time it is getting hot, the iron
wheel, previously turned to the right diameter, is bolted down upon a
face-plate or surface; the tire expands with the heat, and when at a
cherry-red, it is dropped over the wheel, for which it was previously
too small, and it is also hastily bolted down to the surface plate; the
whole load is quickly immersed by a swing crane into a tank of water
about five feet deep, and hauled up and down until nearly cold; the
tires are not afterwards tempered. It is not indispensable that the
whole tire should be of steel, but a dovetail groove turned out of the
tire at the place where it bears most on the rail, and fitted with a
band of steel, which may be put in in pieces, is sometimes adopted,
though at the risk of being thrown off in working. The steel, after
being introduced, is well hammered, which expands it sideways, until
it fills the dovetail groove, but it has sometimes come out. The tire
is attached to the rim by rivets with countersunk heads, and the
wheel is then fixed on its axle. The tire is turned somewhat conical,
to facilitate the passage of the engine round curves-the diameter of
the outer wheel being virtually-increased by the centrifugal force, and that of the inner wheel corre-
spondingly diminished, whereby the curve is passed without the resistance which would otherwise arise
from the inequality of the spaces passed over by wheels of the same diameter fixed upon the same axle
The rails, moreover, are not set quite upright, but are slightly inclined inwards, in consequence of which
the wheels must either be conical or slightly dished, to bear fairly upon them. One benefit of inclining
the rails in this way and coning the tires is, that the flange of the wheel is less liable to bear against the
side of the rail, and with the same view the flanges of all the wheels are made with large fillets in the
corners. Wheels have been tried loose upon the axle, but they have less stability, and are not now
much used.
In all locomotives, there is a very material loss of power from the contraction of blast-pipe necessary
to maintain the blast; at high speeds one half of the power of the engine is lost by the inadequate area
of the steam passages, of which the greatest loss is that arising from the contraction of the blast-pipe.
Tenders are now made larger to obviate the necessity of so many fuel and water stations. Tenders
can be put on any number of wheels, so that inconvenience is not likely to arise from their size and
weight.
Cranked axle.-The cranked axle is made of wrought-iron, with two cranks forged upon it, towards the
middle of its length, at a distance from each other answerable to the distance between the cylinders;
bosses are made on the axle for the wheels to be keyed upon, and there are bearings for the support of
the framing. The axle is usually forged in two pieces, which are then welded together. Sometimes
the pieces for the cranks are put on separately, but those 80 made are liable to give way. In engines
with outside cylinders the axles are straight, the crank-pins being inserted in the naves of the wheels.
The bearings to which the connecting-rods are attached are made with very large fillets in the corners,
so as to strengthen the axle in that part, and to obviate side play in the connecting-rod. In engines
which have been in use for some time, however, there is generally a good deal of end play in the bear-
ings of the axles themselves, and this slackness contributes to make the oscillation of the engine more
violent.
Connectiny-rods.-It is very desirable that the length of the connecting-rod should remain invariable,
in spite of the wear of the brasses, for there is a danger of the piston striking against the cover of the
cylinder, if it be shortened, as the clearance is left as small as possible, in order to economize steam. In
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some engines the strap encircling the crank-pin is fixed immovably to the connecting-rod by dovetailed
keys, as shown in Fig. 1448, and a bolt passes through the keys, rod, and strap, to prevent the dovetail
keys from working out. The brass is tightened by a gib and cutter, which is kept from working loose
by three pinching screws, and a cross-pin or cutter through the 1448.
1447.
point. The effect of this arrangement is to lengthen the rod, but
at the cross-head end of the rod the elongation is neutralized, by
making the strap loose, 80 that in tightening the brass the rod is
shortened by an amount equal to its elongation at the crank-pin
end. The tightening here is also effected by a gib and cutter,
which is kept from working loose by two pinching screws press-
ing on the side of the cutter. Both journals of the connecting-rod
g
are furnished with oil-cups, having a small tube in the centre,
with siphon wicks. The connecting-rod, represented in Figs.
1448, 1447, is a thick flat bar, with its edges rounded. Stephen-
son's connecting-rod is made at the crank end; a strap of round
iron passes over both brasses, and is attached to the T end of the
connecting-rod by means of nuts upon the ends of the bent iron,
which is made thickest in the middle, to resist the strain. This
plan has the defect of shortening the connecting-rod when the
brasses are screwed up, and the brasses require to be very strong
and heavy. Hawthorn's connecting-rod has a strap at each end,
tightened by a gib and cutter; but, to obviate the tendency to
shorten the rod, the piston-rod end is furnished with a cutter for
tightening the brass outwards. The point of the cutter is screwed,
and goes through a lug attached to the gib, and is tightened by
a nut. It would be preferable to attach the lug to the cutter and
the screw to the gib, as the projection of the screw, when the cut-
ter is far in, would not then be so great. In the engines on the
Rouen Railway the piston-rod end of the connecting-rod has nei-
ther strap nor brass, but simply embraces the cross-head, while
the crank end is hollowed out to admit brasses, which are tight-
ened by a gib and cutter. The length of the connecting-rod va-
ries from four times the length of the crank to seven times. The
long connecting-rod has the advantage of diminishing the friction upon the slides.
Eccentrics and eccentric-rod.-The eccentrics are made of cast-iron; and when set on the axle between
the cranks, they are put on in two pieces held together by bolts, as shown in Figs. 1449, 1450: but in
straight-axle engines they are cast in a piece, and are secured on the shaft by means of a key. The
eccentric, when in two pieces, is retained at its proper angle on the shaft by a pinching screw, which is
provided with a jam-nut to prevent it from working loose. A piece is left out of the eccentric in cast-
ing it, to allow of the screw being inserted, and the void is afterwards filled by inserting a dovetailed
piece of metal. Stephenson and Hawthorn leave holes in their eccentrics on each side of the central
arm, and they apply pinching screws in each of these holes. The screws sometimes slacken and allow
the eccentric to shift, unless they are provided with jam-nuts. In the Rouen engines with straight axles,
the four eccentrics are cast in one piece.
Eccentric straps are best made of wrought-iron, as inconveni-
1450.
1449.
ence arises from the frequent breakage of brass ones. When
made of malleable iron, one-half of the strap is forged with the
rod, the other half being secured to it by bolts, nuts, and jain-
nuts. Pieces of brass are in some cases pinned within the mal-
leable iron hoop, but it appears to be preferable to put brasses
within the strap to encircle the eccentric, as in the case of any
other bearing. When brass straps are used, the lugs have gen-
erally nuts on both sides, so that the length of the eccentric-rod
may be adjusted; but it is better for the lugs of the hoops to abut
against the necks of the screws, and if any adjustment is neces-
sary from the wear of the straps, washers can be interposed. In
some engines the adjustment is effected by screwing the valve-
rod, and the cross-head through which it passes has a nut on either side of it by which its position upon
the valve-rod is determined. The forks of the eccentric-rod are steel. The length of the eccentric-rod
is the distance between the centre of the crank axle and the centre of the valve-shaft.
Valve motions.-In locomotives the eccentrics are now always fixed upon the axle, and two are used,
one for the forward, the other for the backward motion: the loose pulleys have been given up on ac-
count of their liability to get out of order from the shocks to which they were subjected by sudden
change of direction when worked at a quick speed. The arrangement whereby the motion of the ec-
centric is transmitted to the valve, is either direct or indirect. In cases of indirect attachment the
motion is given through the intervention of levers, and there is some variety in the arrangements by
which the reversing is accomplished. Alcard and Buddicome use a pair of eccentrics at the end of the
axle, which is straight; the reversing shaft is placed below the level of the piston-rod, and to a lever
keyed upon it are attached links of unequal length, connected at their upper extremities with the ends
of the eccentric-rods, one of which is above and one below the studs on the lever of the valve-shaft, 80
that the upper eccentric-rod, being in geer, gives the forward motion, and the lower gives the backward
motion. In other engines, forks are situated above and below the stud of the eccentric levers; the for-
ward eccentric-rod is lifted up out of geer by a link depending from the lever on the reversing shaft,
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and by the same movement the backing eccentric is lifted into geer by a longer link connecting it to a
lever, not upon the reversing shaft, but upon a shaft below it. Stephenson and Hawthorn have both
used a similar arrangement, but admitting of the eccentric-rods being both under the studs of the lever
on the valve-shaft, so that there is no danger, in the event of a disengaged rod falling down, or of any
part of the geering being bent or twisted by both rods being in geer at the same time. The motion of
the eccentrics is now frequently transmitted directly to the valves. In Pauwel's arrangement of valve
geering, the valve works on the side of the cylinder, and the valve-rod is prolonged in the form of a
deep flat blade of a lozenge section, on each side of which a stud is fixed,-one being intended for the
notch of the forward eccentric-rod, and the other for that of the reversing eccentric. Above them is
fixed the reversing shaft, from a lever on which depend two links of unequal length, which are jointed
to the ends of the eccentric-roda. By working this lever up or down, the eccentric-rods will be alter-
nately engaged and disengaged, and will communicate their respective motions to the valve; or if the
lever be kept in its mid position, both eccentrics will be out of geer, and the valve of course will remain
stationary. Pauwel's engines are difficult to work, and are subject to shocks from going suddenly into
geer: this arises from the whole weight of levers and rods being on the front of the reversing shaft, but
the evil might be remedied by attaching a counterbalance to the shaft. Valves situated upon the sides
of the cylinders are in many cases more easily connected with the eccentric, but they require springs to
keep them up to the face, so that it appears preferable to make the faces of the two cylinders inclined
to one another rather than upright, if valves on the sides of the cylinders are preferred. Stephenson's
link motion is the most elegant, and one of the most eligible modes of connecting the valve with the
eccentric yet introduced. The nature of this arrangement will be made plain by a reference to Fig.
1451, where c is the valve-rod which is attached by a pin to an open curved link connected at the one
1451.
end with the driving eccentric-rod d, and at the other with the backing eccentric-rod d'. The link with
the eccentric rods is capable of being moved up or down by the rod f and bell crank f", situated on
the shaft g, while the valve-rod remains in the same horizontal plane. It is very clear that each end of
the link must acquire the motion of the eccentric-rod in connection with it, whatever course the central
part of the link may pursue, and the valve-rod will partake most of the motion of the eccentric-rod that
is nearest to it. When the link is lowered down, the valve-rod will acquire the motion of the upper
eccentric-rod, which is that proper for going ahead; when raised up, the valve-rod will acquire the
motion of the reversing eccentric, while in the central position the valve-rod will have no motion, or
almost none. The link motion therefore obviates the necessity of throwing the eccentric-rod out of
geer; it also enables the engine to be worked to a certain extent expansively, though as a contrivance
for working expansively, we cannot hold it as deserving of much commendation. The dead point of the
link motion is where the line of the valve-rod bisects the angle formed by the eccentric rods. The
maximum forward motion is when the rods are as figured, and the maximum backward motion when
the rods d and d' are in the position h" and h'. The best forms of the link motions have side studs, to
which the ecrentric-rods are connected, and these are placed so that at the greatest throw, whether
1452.
backward or forward, the valve-rod and eccentric-rod are in the same straight line, and the valve re-
ceives the full throw of the occentric. A counter-weight is also attached to the shaft to balance the
weight of the link and rods. The second eccentric and eccentric-rod of the link motion might, it appears
to us, be beneficially dispensed with by placing the shaft g in the plane of the valve-rod, and attaching
a pin to the centre of the link, which would work in the eye of the horizontal arm of the lever f. This
lever would in such case require to be made much stronger than at present, as it would have to with-
stand the thrust of the eccentric, and the link would then virtually be a double-ended lever with a
movable centre. Where more convenient, the pin in the centre of the link might be moved in vertical
or curved guides, instead of being attached to the lever f. The act of raising the link, and with it the
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eccentric-rod, would in effect alter the position of the eccentric on the shaft, and if the eccentric-rod
were properly proportioned in length, would make the lead right on the reversing side.
The movement for working the valves is in some cases derived from the connecting-rod, as iL the
arrangement known as Melling's motion, represented in Fig. 1452, where the valve-rod is attached by
suitable connections to a pin in the connecting-rod.
A somewhat similar mode of working the valve has been employed by Hawthorn, of Newcastle,
which admits of expansive action, and which is represented in Fig. 1452a. The pin in the connecting-rod
works in a link, to which arms are attached at right angles. The extremity of the lower of these arms
is connected by a link and lever to a shaft, which is worked by the reversing handle, while the upper
arm is attached to a lever upon the valve-shaft. Upon this shaft there is a double-ended lever, with
either end of which a rod, in communication with the valve, geers, according as a forward or reverse
motion is wanted. This valve-link is connected by a link with the starting-shaft. The central slot in
he link permits the free end movement of the pin on the connecting-rod, while the lateral movement is
communicated to the link, and made available for working the valve ievers. To reverse the engine, the
inclination of the link must be altered, and the fork in geer must be changed to the other end of the
lever, which is done by the same handle: the lead is regulated by the degree of inclination of the par-
allelogram, which might be changed by lengthening the lever on the reversing-shaft connected with the
lower arm of the link, or by shifting it round on the shaft 80 as to throw the lower arm towards the
cylinder. There is much complication in this arrangement; the parts, too, require to be large, and the
plan has not been received with much favor, although good results have been obtained.
1452a.
If
PT
Variable expansive action has recently been extensively introduced in locomotives, and the whole of
the various expedients for its accomplishment operate either by altering the travel of the valve, or by
the introduction of superposed valves. The first mode is that adopted by Stephenson and Cabrey, and
the second is principally used by Mayer and Gonzenbach. In the first the effect is to uncover the steam
ports less, and re-shut them sooner; to hurry the eduction, and to compress the steam shut within the
cylinder: from the early closing of the eduction, the advantages due to expansion are partly sacrificed,
for the steam escapes before it has done all its work, and power is lost in the compression of vapor.
The second class of expansion contrivances is not chargeable with these defects. It admits of the steam
being cut off at any part of the stroke, without any derangement of the valve motion, but there is greater
complication in the apparatus. In the class with variable throw, the cutting off is the result of a vir-
tual contraction of the ports, which wire-draws the steam, increasing the speed of the entering steam,
and making the pressure in the cylinder less than in the passages. In Cabrey's expansion geer, the
fault is, that for certain degrees of travel, and when there is much cover on the valve, it may happen
that instead of opening the port before the end of the stroke, the valve may not have uncovered the
steam port when the piston is about to begin the return stroke. This evil results from the invariable
position of the eccentrics on the shaft, and the immobility of the centre of the valve lever. Stephenson
gets rid of the defects of Cabrey's system in regard to changing the lead of the eccentric, by rendering
movable the centre of oscillation of the valve lever, as the link may be considered, whereby he vir-
tually turns round the eccentric on the axle. Mayer's geer has given very good results, and is free from
the defects of Cabrey's and Stephenson's. Whatever be the degree of expansion, it presents the same
area of steam port; the eduction is not unduly hurried, the linear lead is unvarying, and the compres-
sion of the steam before the piston is but small, and is not liable to increase. The wheel and chain
geering, however, used in working it, are very troublesome, and liable to get out of order, and the valves
have a great deal of friction. Gonzenbach's has less friction than Mayer's, and gives equally good
results.
How to set the valves of locomotives.-When the cylinder is horizontal the crank is horizontal at the
ends of the stroke; but it is not vertical when the piston is at the middle of its stroke, owing to the
deviation from parallelism introduced from the connecting-rod being compelled to move at one of its
extremities in a straight line. When the piston is at the end of the bottom stroke, and is gradually
advanced towards the middle of the stroke, the end of the connecting-rod is carried round by the crank
in a curve opposed to that which it would naturally describe round the cross-head as centre; but when
the piston has approached the end of the top stroke, the curvature of the path in which the end of the
connecting-rod is moved by the crank is in the same direction as that of the circle which it would de-
scribe round the cross-head, and these curves would coincide if the connecting-rod were equal in length
to the crank: it will be easily seen, therefore, that at the top stroke the piston-rod requires but a small
movement to enable the end of the connecting-rod to traverse a large portion of the circle of the crank,
while at the bottom stroke the piston has to travel farther to allow of an equal are being described by
the crank. From these considerations it follows, that the motion of the crank being nearly uniform,
there must be considerable inequalities in the speed of the piston; and more than a half circle will be
described by the crank during the top half of the stroke, and less than a half circle in the bottom half
of the stroke. The length of the connecting-rod is the distance from the cross-head at half stroke to the
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centre of the shaft; and it is clear, therefore, that at mid-stroke the crank cannot be vertical. The mo-
tion of the valve partakes of the same species of irregularity; but as the eccentric-rod is much longer
in proportion to the radius of the eccentric than the connecting-rod, that inequality only may be noted
which arises from the relation between the circumference of a circle and its diameter. The irregularity
arising from the angle of the connecting-rod also affects the valve, but not to an injurious extent in ordi-
nary cases. In Fig. 1453 we have shown the direct connection, as used in some of Stephenson's loco-
motives, A EBF representing the crank circle, and the inner circle that of the eccentric. Supposing.
now, that the total length of the valve face were equal to the distance between the extreme edges of
the steam ports, the valve would be without lap and leaving the question of lead out of consideration
for the present, that is, supposing that the steam were admitted exactly at the ends of the stroke, the
eccentric would be fastened upon the shaft at right angles to the crank; in other words, the small crank
which constitutes the eccentric would be at right angles to the large crank, which is attached to the
piston-rod. In this way the valve would be in the middle of its stroke when the piston was at either
end of its stroke, so as to close both the steam and eduction passages, and to be ready with the slightest
possible advance, to open both for the return stroke of the piston. It has been found advantageous,
however, to make the valve face longer than the distance between the extreme edges of the steam ports,
so that when it is in the middle of its stroke, it projects or overlaps the ports at both ends; and hence
it requires to move through a space equal to the overlap before it is in a condition to open the steam
port for the return stroke of the piston. To effect this, it is only necessary to move the eccentric for-
ward in its path, until, at the end of the stroke of the piston, the valve is on the edge of the steam port,
ready, as before, upon the slightest farther advance, to admit the steam to the cylinder. Now, as the
valve is thus required to move through a part of its travel or throw equal to the overlap at each end,
and as the throw is equal to the diameter of the circle which the eccentric describes, it follows that, to
give the requisite advance, that distance must be measured upon the diameter of the circle, and the cor-
responding position of the centre of the eccentric is that of which we are in search.
E
1453.
M
A
H
K
B
N
F
On the remote side of the centre of the crank-shaft, and on the line of centres, mark off DC, the
amount of overlap at each end of the valve, and draw a line parallel to EF, the vertical centre line of
the crank-shaft; the arc of the eccentric circle intercepted between these parallel lines is that through
which the eccentric must move, in order to draw the valve through a portion of its stroke equal to the
overlap DC; and the point in which the line intersects the circle of the eccentric is, therefore, the posi-
tion which the centre of the eccentric should occupy when the piston is at the end of its down-stroke,
and on the very point of beginning its up-stroke. In practice, however, the valve is not so set as to
open simultaneously with the commencement of the stroke of the piston, but is set so that the steam
commences to flow into the cylinder a very little before the beginning of the stroke; and hence, when
the piston actually commences its stroke, the valve has already partially opened the port. To make
this adjustment, an additional advance must be given to the valve, and of course in the same direction;
and the amount of lead, or opening, which the port has at the commencement of the stroke of the piston,
must be added to the lap, their sum from C to D being treated the same in every respect as if the
whole were lap and so, for the sake of brevity, we may treat it.
Let us suppose now that it was required to find the length that the eccentric-rod should be:-Place
the crank horizontal, so that it may have the piston at the bottom of its stroke; bring round the eccen-
tric to the corresponding position which we find it should occupy, and measure the distance from that
point to the centre of the joint by which the eccentric-rod is to be attached to the valve-rod; this will
be the length of the eccentric-rod. When the length of the eccentric-rod is known, either the valve or
eccentric may be put in its proper place, if one of them be already set: thus, if the valve be set, as in
the drawing, and the eccentric-rod connected also with the eccentric, it will bring the latter into its
place, where it may be fixed; but if the valve could not be conveniently set, it would then be necessary
to take the following method, which requires the knowledge of the amount of lap, and the length of the
eccentric-rod. Find, as before, the position of the eccentric, attach the rod, and the valve must come
into connection in the proper position. In practice, the most convenient method of finding the position
of the eccentric with a given lap is to draw a circle, such as HK, representing the crank-shaft, upon a
board or a piece of sheet-iron, and another equal to the circle of the eccentric, and draw two diameters
perpendicular to each other mark off from the centre of the crank-shaft, and upon one diameter, the
amount of lap CD; through this point draw a line parallel to EF, the other diameter; the points in
which this line cuts the circle of the eccentric are the positions of the forward and backward eccentrics.
Through these points, and from the centre of the crank-shaft, draw lines CM, CN, which will intersect
the circumference of the crank-shaft; upon this circumference measure with a pair of compasses the
chord of the arc intercepted between either point of intersection and that of the vertical diameter EF;
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and the lines of diameters being first drawn upon the shaft itself, then, by transferring with the com-
passes the distance found upon the diagram, the proper position of the eccentric at the end of the stroke
of the piston is at once determined; and this being marked upon the shaft, the eccentric can at any
time be set, by bringing it round to that mark. Before leaving this figure we may remark, that as the
valve in Stephenson's locomotives of this kind is on the side of the cylinder, the cylinder face should be
towards us in the drawing. As this arrangement, however, would have afforded a less easy explana-
tion, we have adopted the present one. It will also be observed that the crank-shaft and cylinder are
too close, and are not in a line with each other; but this, while it could not be easily avoided, is at the
same time of no importance in considering the respective motions of the piston and valve, crank and
eccentric, which are shown in their true relative positions. The crank is upon the centre, and the piston.
consequently, at the end of the bottom stroke; the eccentric and valve being put in advance of the
piston by the lap, have shut off the steam before the end of the stroke, and have also opened the educ-
tion in readiness for the up-stroke; whereas, without lap, the valve would shut off the steam at one end.
and open the eduction at the other, simultaneously with the termination of the stroke of the piston.
1454.
In Fig. 1454 we have a different kind of valve geering, there being levers, which reverse the direction
of the motion; that is, while the eccentric-rod and lever are moving in one direction, the valve-rod and
lever, being on the opposite side of the weigh-bar shaft, are moving in the opposite direction. In the
former case there were no levers, and therefore no reversal of the motion. Hence, in order to give the
valve the same motion as before, in relation to the crank, it is necessary to throw the eccentric to the
opposite side of the crank-shaft, so that its motion may be in the reverse direction, to compensate for
the reversing action of the levers. For whereas, when upon one side of the shaft they caused the valve
to move in the same direction as themselves by means of the eccentric-rods, now that the levers are
introduced, the eccentrics must themselves move in an opposite direction, to give the valves the same
motion as heretofore. And this can only be done by putting the eccentrics on the opposite side of the
crank centre, round which they move, and, of course, in an opposite direction.
1455.
Fig. 1455 is intended to illustrate the valve connection of the common locomotive, in which the mo-
tion of the eccentric is communicated through levers to the valve, and generally with an increase of
throw. In this figure we have the cylinder face, with the valve upon it, at one end of its travel.
Measure off the length of the valve throw, from the end of the valve face, in the direction of its travel.
The throw of the valve may best be found by adding the lap to the breadth of the steam-port, and dou-
bling their sum. If there were no levers intervening between the valve and eccentric, the line thus
measured, which is the throw of the valve, would be the diameter also of the circle described by the
centre of the eccentric pulley; but the use of levers interferes with this proportion unless the levers be
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made of equal length. The effect of levers of unequal length, in making a proportional inequality be-
tween the throw of the valve and of the eccentric, will be readily seen by reference to a diagram. From
the centre A of the diameter, representing the throw of the valve, draw a line perpendicular to the
valve face; and from the same point measure off, upon that line, the length of the lever A B, which is
to be attached to the valve-rod, and which, for distinction, we shall call the valve lever. From the
point B thus found as a centre with the radius B A, describe a portion of a circle intersecting perpendic-
ulars drawn from C and D, the extremities of the line which represents the throw of the valve; from
those points in the circumference of the circle produce lines through the centre B. On either side of the
centre line A E, and at a distance from it equal to the radius of the eccentric, draw a parallel line.
From B as a centre, with the distance from the centre B to the points HK,-in which the parallels in-
tersect the produced lines of the lever, as radius,-describe an arc of a circle; the radius of this circle is
the length which the eccentric lever must be, in order to give the requisite throw to the valve. It will
be evident from the inspection of this diagram, that if it be desired to give a smaller throw to the valve
than that of the eccentric, it is necessary to make the valve lever shorter than the eccentric lever; and
if it were desired to make the valve throw greater than the eccentric throw, it is indispensable that the
valve lever should be made proportionally longer than the eccentric lever. If, for example, the throw
of the valve is to be made twice the throw of the eccentric, then this can only be accomplished by mak-
ing the valve lever twice the length of the eccentric lever. Hence the relations between these quan-
tities are expressed by simple proportion; and any three being given, we can readily find the remain-
ing one. For the sake of clearness, we shall state the various forms which the proportion will assume.
First-Given the throw of the valve, the throw of the eccentric, and the length of the lever attached
to the valve-rod, to find the length of the eccentric lever; we have then the proportion:-
Rule-As the throw of the valve is to the throw of the eccentric, 80 is the length of the valve lever
to the length of the eccentric lever.
If we represent the throw of the valve by T, that of the eccentric by t, the valve lever by L, and the
eccentric lever by l, we will have the proportion in a condensed algebraic form, thus,-T t: l; or
taking the actual dimensions in inches of the engine before us, 45:3::9:6.
Secondly.-Given the throw of the valve, the throw of the eccentric, and the length of the eccentric
lever, to find the length of the valve lever. Then,
Rule.-As the throw of the eccentric is to the throw of the valve, so is the length of the eccentric
lever to the length of the valve lever;
Or, algebraically, t:T::1: L; or, as before, in actual dimensions, 8:45::6:9.
Thirdly.-Given the throw of the valve and the lengths of the levers, to find the throw of the ec-
centric.
Rule.-As the valve lever is to the eccentric lever, so is the valve throw to the eccentric throw;
Or thus, L l T or, 9: 3.
Fourthly.-Given the eccentric lever, the valve lever, and the eccentric throw, to find the valve throw.
Rule-As the eccentric lever is to the valve lever, so is the eccentric throw to the valve throw;
Or, 1: L T; or,6:9::3:45.
We formerly explained how the reversing action of the levers rendered it necessary to set the eccentric
on that side of the crank-shaft centre nearest to the cylinder; whereas, in the case of the direct valve
connection, it was set on the side remote from the cylinder. Having now found the means of ascertain-
ing the lengths of the levers to be employed with a given throw of valve and eccentric, the next step
necessary is to determine the true position of the eccentric upon the shaft, in reference to the crank.
Place the crank-pin in the dead point nearest the cylinder; that is, place the centres of the crank-
shaft and crank-pin in a line with the centre line of the piston-rod. Upon this line of centres A G, raise
a perpendicular M, through the point F. From F draw a circle, the diameter of which is equal to the
throw of the eccentric, and another equal to the cranked axle. If the levers are equal, mark off from
F, upon the line of centres and on the cylinder side, the amount of lap, and draw a line parallel to L M,
cutting the eccentric circle in the points NO. From F draw lines through N and o to the circumference
of the cranked axle. The points N and o are the positions of the centres of the eccentric pulleys for
the forward and backward geer, only one of which is necessary for going one way. In practice it is
convenient to make marks at PR, as the points N and o are inaccessible. If there were no lap upon
the valve, there would be nothing to set off from the centre line LM, and therefore that line would give
the positions of the eccentrics.
The intersections of the perpendicular A G would give the positions of the eccentrics on the shaft if
the connecting-rod were infinitely long; but inasmuch as the shortness of the connecting-rod introduces
irregularity, the true position of the crank at the middle of the stroke of the piston must be taken.
If the lengths of the levers be unequal, the throws of the eccentric and valve will also be unequal;
and if the valve lever be the longer, as in the case we have taken, the eccentric throw is less than the
valve throw in the same proportion as the eccentric lever is less than the valve lever; and therefore,
since the eccentric throw is thus less than the valve throw, by reason of the levers, it follows that the
lap, which we set off from F, and which is part of the valve throw, must also be diminished in the same
proportion as the whole throw, in order to set off the proper quantity from F. The simplest way of
accomplishing this is, by marking off the lap from the line of centres, Fig. 1455, at the point A, at the
same end as we formerly marked off half the valve throw. This distance will be from A to the edge
of the port, that being the overlap; then from the edge of the port draw a parallel to A G; and from
the point in which this parallel cuts the are of the longer lever, draw a line through the centre B, and
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521
produce it till it cuts the arc K H; the perpendicular from this point to the line E A is the reduced
amount of lap, which is to be set off from the point F.
Another useful problem is the method of finding the length of the eccentric-rod, the positions of the
crank-shaft, and the weigh-bar shaft, and the length of the eccentric lever being given. From the centre
of the weigh-bar shaft, with the length of the eccentric lever as radius, describe an arc; draw a tangent
from this to the centre of the crank-shaft; from the centre of the weigh-bar shaft drop a perpendicular
to the tangential line; the distance from the point of intersection to the centre of the crank-shaft is the
length of the eccentric-rod, and the perpendicular is the line of the eccentric lever, when the valve lever
is perpendicular to the line of the valve-rod: this gives, therefore, the positions in which these levers
must be keyed upon the weigh-bar shaft.
In Fig. 1455 the mid-line of the eccentric-rod was the same as the line of the piston-rod; but in Fig.
1454 it is thrown down below that of the piston-rod, forming an angle with it, the vertex of which is the
centre of the crank-shaft. In this case the centres of the eccentric pulleys must, consequently, be moved
downwards as many degrees as the central line. In order to facilitate this adjustment, we may briefly
explain, that every circle is supposed to have its circumference divided into 360 equal parts, called
degrees; and if two diameters be drawn in it at right angles to each other, they will divide the circum-
ference into four equal parts, each of which contains 90 degrees. This, therefore, is the means by which
the angle is measured; nor will it matter, although the circle be of any size whatever, for it is still
equally divided by the two diameters. Hence, if the number of degrees contained in the angle which
the mid-line of the eccentric-rod makes with the line of the piston-rod, be measured upon any circle
described from the centre of the crank-shaft, and the angle be laid down upon a board, and if from the
vertex of the angle a circle be described equal to the diameter of the crank-shaft, the chord of the are
of this circle intercepted between the lines containing the angle, is the distance to be transferred upon
the crank-shaft, and through which the eccentric pulley must be moved round, in order to compensate
for the obliquity of the eccentric-rod. In the example, Fig. 1454, the mid-line of the eccentric-rod, when
in geer, lies at an angle of five degrees with the line of the piston-rod; and in all such cases this line is
to be taken when reference is made to the valve motion; and the piston-rod line is to be taken when
reference is made to the motion of the piston. In the case of Fig. 1455, these lines were made to coin-
cide, for the sake of simplicity.
Miscellaneous remarks respecting locomotives.-The tractive force requisite for drawing carriages over
well-formed and level common roads is about 1-36 of the load, at low speeds. On railways, the tractive
force has generally been rated at about 1-300 of the load, or 73 pounds per ton, at low speeds; but in
well-formed railways the tractive force is probably less than this, to keep the train moving slowly. The
resistance of railway trains, however, increases rapidly with the speed, on account of the resistance of
the atmosphere; and the resistance occasioned by the atmosphere may be taken at 15 pounds per ton,
with an ordinary passenger train moving at the rate of 30 miles an hour. The friction of the engine
and the resistance of the rails vary simply as the velocity, if the power of the engine remains the same;
but the resistance of the atmosphere varies as the square of the velocity, and the power requisite for
overcoming that resistance as the cube of the velocity: so that by doubling the speed of a train, by dimin-
ishing the load without increasing the power, the friction is doubled, the atmospheric resistance is made
four times greater than before, and the power requisite to overcome that resistance eight times greater.
This shows the extravagance of high speeds, even if the power were as economically produced at high
speeds, which is by no means the case. In moderately light trains upwards of 50 per cent. of the power
is expended in overcoming atmospheric resistance, in speeds of about 35 miles per hour; and the loss
will be greater if the trains be very light, and present a large frontage.
We have already stated that in low-pressure condensing engines the evaporation of one cubic foot of
water from the boiler may be taken to represent a horse power. In high pressure engines, working
without expansion, the mechanical efficacy of a cubic foot of water raised into steam will be somewhat
less, on account of the resistance to the motion of the piston, occasioned by the pressure of the atmos-
phere; but in locomotive-engines, where the working pressure is very high, the resistance due to the
pressure of the atmosphere becomes relatively nearly as small as the resistance due to the rare vapor
within the condenser of a condensing-engine; and it will not, therefore, be a material deviation from the
truth if, in locomotive-engines, working without priming, we reckon a cubic foot of water evaporated
per hour as equivalent to a horse power. An engine evaporating 200 cubic feet of water per hour, and
therefore exerting about 200-horse power, draws about 110 tons at thirty miles an hour; but if there
were no loss from the resistance of the atmosphere, or of the blast-pipe, and no increased friction upon
the engine from the increased power requisite for high speeds, the tractive force, if taken at 8 pounds
per ton, would only require to. be 70:4-horse power for 110 X 8 X 2640, the number of feet travelled
per minute at 30 miles an hour, ÷ 33000 = 704-horse power. The friction of the train, however, at
80 miles an hour, including that of an engine of 200-horse power, cannot be taken at much less than 10
pounds per ton; for the friction of an engine increases with the power exerted, which determines the
pressure upon its moving parts; and the friction of the carriages is also increased at high speeds, in
consequence of the draw-bars being attached below the centre of effort of the frontage exposed to the
wind, whereby the carriages are pressed down more firmly on the rails. If the traction be taken at 10
pounds per ton, then the power requisite for propulsion of a train, setting aside the resistance of the
atmosphere, will be about 90-horse power, and the remaining 110-horse power is absorbed in overcoming
the resistance of the atmosphere and of the blast-pipe. If the speed be increased from 30 to 60 miles
an hour, about 200-horse power will be required for overcoming the friction of the train, and 880-horse
power will be required to overcome the atmospheric resistance; making 1,080-horse power, which will
be necessary to propel a train of 110 tons at 60 miles an hour. The evaporation of a locomotive boiler
is greatest when the speed is at its maximum, as the blast-pipe then produces its greatest effect; and
the power of the engine varies nearly as the rate of evaporation, provided the blast-pipe be not unduly
contracted. At ordinary railway speeds the power of the boiler is seven or eight times greater than it
66
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would be without the blast, though, indeed, such a comparison hardly holds, as without the blast the
fire of a locomotive boiler would not draw at all. At a speed of 20 miles an hour, a locomotive boiler
boils off from 10 pounds to 14 pounds of water per square foot of beating-surface, and the rate of evap-
oration varies nearly as the of the speed.
The adhesion of the wheels upon the rails is about one-fifth of the weight when the rails are clean,
and either perfectly wet or perfectly dry; but when the rails are half wet or greasy, the adhesion is
not more than one-tenth or one-twelfth of the weight. The weight of locomotive engines varies from
15 to 20 tens. A powerful locomotive engine and tender, such as is suitable for high speeds, will weigh
about 25 tons. The consumption of power by the locomotive itself is very great at high speeds, chiefly
in consequence of the resistance occasioned by the blast-pipe to the free escape of the steam. Mr. Ste-
phenson considers that, at ordinary railway speeds, a locomotive engine will absorb as much power as
15 loaded carriages, weighing 60 tons; so that in a train of 15 carriages, half the power is consumed by
the engine. These determinations, however, are all very indefinite, and experiments are yet wanting to
show the power produced and consumed by locomotives under different circumstances. Locomotive
engines in England cost from $9,000 to $11,000 each. They run, on an average, about 130 miles a day,
at a cost for repairs of about 5 cents per mile; and the cost of locomotive power, including repairs, wages,
oil, and tallow, and coke, may be taken at 12 cents per mile, on economically managed railways. This
does not include a sinking fund for the renewal of engines which may be worn out, and which may be
taken at 10 per cent. on the original cost of the locomotives. On second class railways the expense of
locomotives, and workshops, and tools for repairing them, may be set down at $10,000 per mile.
Economy of fuel in locomotives is materially promoted by working expansively; but all attempts at
economizing fuel in locomotives should begin with an increase in the area of the fire-grate, 80 that the
power of the engine may not suffer so large a diminution by the creation of the necessary draft.
Every locomotive engine should be furnished with efficient expansion apparatus, of some kind or
other as, setting aside the economy of fuel accomplishable by expansion, it is clear that expansion acts
beneficially by diminishing the weight of the boiler, which may be made smaller at every increase of
the efficiency of the steam. When the draft is strong, a great loss of effect is caused by opening the
furnace door, from the refrigeration due to the large volume of air admitted; and it would be a material
improvement if the furnace could be fed by some such mechanism as the revolving grate. The use of
sediment-collectors in locomotive boilers also appears expedient, as, if judiciously applied, they will
effectually prevent the formation of scale upon the tubes, and will also operate as an antidote to
priming in many cases. The form of collector best adapted for a locomotive boiler, will depend in a
great measure upon the peculiar structure of the boiler; but generally any form will answer which
communicates with the water level, and contains water within it in a tranquil state. The V-shaped
cuts for establishing the communication between the exterior and interior of the vessel, have been found
preferable to holes of any other form; for a subsiding particle, so soon as it falls in a slight degree, gets
behind the case of the collecting vessel, and cannot afterwards escape.
Details of the engines of steam-frigate Dragon.-Fig. 1456 represents the paddle and intermediate
shafts from the centre line of the vessel to the outer bearing. In this figure are introduced a section of
one of the cranks and of the cam for working the expansion valve.
Fig. 1457 is a sectional view (taken through the centre of the valve face) of the cylinder and piston,
with the piston-rod and cross-head.
Fig. 1458 shows a plan and sections of the elastic packing-ring at the middle and ends.
Fig. 1459 is a sectional view of the steam-pipe, showing the expansion and throttle valves.
Fig. 1460 represents a vertical section of the expansion-valve detached.
Fig. 1461 is a transverse section of the air-pump and feed-pump with their appendages. In this
figure are also introduced external views of the air-pump rod and cross-head, and of the plunger-rod of
the feed-pump.
Figs. 1462 and 1463 show the air-pump link.
Figs. 1464 and 1465 the connecting-rod.
Figs. 1466 and 1467 the long parallel-motion beams which work the air-pump.
Fig. 1468 the radius-rod for the parallel motion.
Literal references.-A, the sole-plate, of cast-iron, 2 inches thick, laid on a solid bed of African oak
16 inches thick, and cast 80 as to form the bottom of the cylinder. It is made of larger dimensions than
are absolutely required for the attachment of the fixed parts of the engines, being extended to some
distance on each side, in order to cover a larger space and to increase the strength of the keelsons and
lower timbers of the ship. The sole-plate does not, however, on that account, occupy additional room,
being 80 constructed as to form the flooring on every side, and at the same time to distribute the weight
and action of the engines over a more extended surface of the flooring.
E, the steam-cylinder, 14 inch thick, cast open at each end, the sole-plate forming the cylinder
bottom. Its internal diameter is 88 inches, and the stroke 5 feet 9 inches. Besides being strengthened
by the flanges at the top and bottom, it is encircled by three belts, each 3 inches deep, in order to give
rigidity to the cylinder when laid horizontal during the process of boring. It is now usual to bore
cylinders of large diameter in a vertical position, to avoid all chance of ellipticity arising from this
cause. The cylinder is fitted with escape-valves for priming or condensed water both above and
below the piston, the valve being loaded to somewhat above the highest tension of the steam in the
cylinder.
dd, the steam-ports, 3 feet 8 inches long, by 77 inches wide.
e, a separate casting for the cylinder face, planed and scraped to a true surface.
i, the throttle-valve, of gun-metal, worked by one of the three handles at v' through a series of rods
and levers.
H, the steam-piston, 81 inches deep at the circumference, and 114 inches at the centre, formed of cast-
iron 1} inch thick, stiffened by radiating feathers.
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j, the external packing-rings, of cast-iron, 21 inches deep, on Goodfellow's patent construction. These
rings are turned concentric, and each, being cut across diagonally, to prevent grooving the cylinder, is
free to accommodate itself to the interior of the cylinder as it wears by the friction of the piston, but
possesses no elasticity in itself.
1459.
A
1460.
i
i
M
G
1456.
1458.
M
1457.
I
I
d
"
H
K
R
k and 1 represent the thick and thin ends of the inner eccentric V-shaped ring, of cast-iron, which, by
its elasticity, presses the two external rings against the cylinder, thus forming a steam-tight joint. The
requisite elasticity is given to this ring by forming in it a series of cuts or grooves increasing regularly
in depth from k, where the ring is entire, to l, where the grooves are deepest; and also by causing the
projections at the back of the rings shown at k to vanish at 1. The ring is 44 inches deep, its thickness
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ENGINES, DETAILS OF.
being 5g inches at the thickest part, and 1 inch at the thinnest. The grooves (86 in number) are, at the
point l, 21 inches deep, and 7-16 inches wide, and they are pitched at 21 inches centre to centre.
m, the junk-ring, of cast-iron, 11 inch thick.
n, a brass nut for fixing the piston-rod.
I, the steam-cylinder cover, cast hollow, with radiating feathers, and with a thin polished plate of cast-
iron for the upper part.
o, the stuffing-box gland, made 80 as to allow the strap of the connecting-rod to clear it on each side.
It is formed of cast-iron, with a brass lining, and packed with hemp.
J, the piston-rod. It is fastened into the piston by a cone and screw n, and further secured by a
cotter.
p, the piston cross-head, of forged iron, secured to the rod by a long cone and cotter. The bearings
for the connecting-rod and the first parallel-motion beams are forged in one piece with it.
M, the connecting-rod, formed with a fork at the lower extremity, which is attached by straps, gibs,
and cotters to the great bearings on each side of the piston cross-head p.
N, the crank, of wrought-iron.
1462.
1463.
1461.
0
r
q
Y
V
v
w, the crank-pin. That portion of it which passes through the crank on the intermediate shaft P is
firmly fixed to it by being driven into a slightly tapered eye, and is further secured by a cotter but at
the opposite extremity it passes loosely through the crank on the paddle-shaft, to allow for the deviation
from the true vertical and horizontal lines of the shafts, occasioned by the unavoidable tendency of the
outer bearing of the paddle-shaft to droop and to wear forwards.
o, the paddle-shaft, of wrought-iron.
x x x, bosses on the paddle-shaft for fixing the paddle-centres.
P, the intermediate shaft, which connects the two engines. The diameter at the centre is 181 inches,
and the bearings are 17 inches diameter, by 18 inches long.
y, the position of the eccentric. In this, as in most other marine engines, the eccentric is not fixed
firmly to the shaft, but revolves between the bearings shown at y, to admit of its turning the valves 80
as to give the engine motion either backwards or forwards. By placing the eccentric loose upon the
shaft, only with a projecting catch on one side which is carried round by a corresponding projection on
the shaft, it is left free, except when this check comes into contact with the other, at either end of the
stroke. To effect this it is necessary to open the valves by hand during at least one-half stroke. The
eccentric, of cast-iron, revolves within a ring of gun-metal The throw of the eccentric is 20 inches; the
diameter of the bearing surface is 3 feet 5/8 inches; the thickness of the gun-metal ring is 11 inch, and
the breadth 4 inches.
o, the air-pump links. Thickness of strap, 11 inch the columr 21 inches, tapered to 1f inch
diameter.
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p, the air-pump cross-head. The diameter over the boes is 11} inches; diameter of hollow cone,
5 7-16 inches, tapered to 5f inches; thickness of blade, 3 inchea.
q, the air-pump rod, formed of wrought-iron, cased with gun-metal, 1 inch thick when finished, cast
round the rod and the cone, to prevent galvanic action.
r, the air-pump bucket, of gun-metal, packed with
hemp.
38, the bucket-valves, of gun-metal, of the descrip-
tion commonly called butterfly-valves. They work on
M
a curved hinge encircling the pump-rod.
tt, discharge valves, also of gun-metal, and of the
same construction as the bucket-valves.
U, the condenser, of cast-iron, 11 inch thick. It is
M
cast in one piece for both engines, with a partition
through the middle to keep the condenser of each dis-
tinct from the other. There is a passage-way through
the lower part of the condenser to the valve-jackets,
1464.
1465.
in order to gain access to the valve-ports for packing
them.
V, the air-pump, of solid gun-metal, t inch thick
when finished, 48 inches diameter, and 34} inches
stroke.
W, the feed-pump, with brass plunger, 91 inches
external diameter, and 841 inches stroke.
Y, the discharge-pipe, of cast-iron, forming the top
of the air-pump. From the air-pump to the sluice-
valve through the ship's side, it becomes a circular
copper pipe, 21} inches bore.
M
Z, the supplementary engine for feeding the boilers
previous to starting the large engines.
vvv, a combination of levers and rods for working.
so, the injection-valve.
M
x, the blow-through or snifting-valve, and i, the
throttle-valve. The connections for each valve are
distinctly shown in the elevation.
y, a graduated cam on the intermediate shaft for
working the expansion geer.
222, a brass roller, levers, and rods for conveying the motion from the cam to the expansion-valve.
The roller is adjusted to each cam by a screw, according to the amount of expansion required.
1468.
1466.
L
%
1467.
L
to
ENGINES, for further details of, See MARINE, LOCOMOTIVE, STATIONABY, PUMPING, HIGH-PRESSURE,
NON-CONDENSING, &c., dc.
ENGINES, rules for calculating the parts of. Rules and tables for facilitating the construction of
boilers, &c., by determining the lengths of plate or angle-iron requisite for the formation of hoops of
different diameters. For plate or flat bar :-
Rule.-Add the thickness of the bar to the required diameter, and the corresponding circumference
in the table of circumferences of circles is the length of the bar.
If the iron be bent edgewise the breadth of the bar must be added to the diameter; for it is the
thickness of the bar measured radially that is to be taken into consideration.
In such pieces of work as the tires of railway wheels, which have a flange on one edge, it is necessary
to add, not only the thickness of the tire, but also two-thirds of the thickness of the flange. Generally,
however, the tire bars are sent from the iron works 80 curved that the plain edge of the tire is concave,
and the flange edge convex; while the side which is afterwards to be bent into contact with the cylin-
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ENGINES, RULES FOR CALCULATING THE PARTS OF.
drical surface of the wheel is a plane. By this means the addition to the diameter of two-thirds the
thickness of the flange is unnecessary; for the curving of the flange edge has the effect of increasing the
real length when only the chord of the arc is measured for the circumference. The radius of the curve
in which the tires are first bent may be safely taken as four times the circumference of the hoop or
wheel. In the form of rules, these results will be, first: when the tire is straight-
Rule.-Add the thickness of the hoop, and two-thirds the thickness of the flange to the diameter, and
find the corresponding circumference.
And when the tire is curved it will be:-
Add the thickness of the hoop to the diameter, and find the circumference.
TABLE OF DIMENSIONS OF THE PARTS OF LOCOMOTIVE ENGINES.
RAILWAYS.
Northern
Bordeaux and
North Mid-
Great
Belgium.
and East-
La Teste.
land Cos.
Western.
Hartlepool.
ern Cos.
ft.
in.
ft.
in.
ft.
in.
ft.
in.
?
in.
ft.
in.
Width of railway between rails
4
81
4
81
4
81
5 0
7 0
4 81
Diameter of boller (inside)
3 41
3
If
3 7t
3 7t
3 111
3 51
Length of ditto
8
2
8
9
8 6
8 0
8 6
8 6
Thickness of plates
0
of
0
0.5
0
of
0
of
0
8
of
0 of
Length of outside fire-box
3
84
3
41
4 0
4 04
4 6
3 7
Breadth of ditto
4 0
3
91
4 0
4 of
4 8
4 1
Depth below boiler
2 0
1
8
2 2
2 2
2 3
2 of
Height above ditto
0
41
not ascertained
2 7
2 7
2 1
0 41
Thickness of plates
0
of
0
of
0
01
0 04
0
of
0 04
Length of inside fire-box
3 of
2
8
3
31
3 34
3 8+
2 104
Breadth of ditto
3
4f
3
2
3 44
3
41
3 10+
3
5±
Thickness of copper plates
0
of
0
of
0
01
0
of
0
of
0 01
Extra thickness of ditto for insertion of tubes
0
of
0
of
0
of
0
of
0
of
0 01
From bottom of fire-box to top of fire-bare
0 8
0 9
0 9
0 8
From top of fire-bars to crown of fire-box
3
41
3
71
3 5
Area of fire-grate in superficial feet
10
21
11
2
11 3
12 10
9 104
Length of smoke-box (inside)
1 111
1
111
2 1
2 1
2
21
2 1
Breadth of ditto (outside)
3 111
4
1
4 2
4
21
5 21
4 2
Thickness of tube-plate
0
of
0
of
0 01
0 of
0 of
0 01
Thickness of side-plates
0 04
0
of
0
04
0 01
0 of
0 01
Diameter of chimney (inside)
1
04
1
0
1 2
1 2
1 4
1 2
Height of top of ditto from rails
13
0
14
0
13 6
14 10
13 6
Number of brass tubes
86
94
123
121
131
105
-
115 at 2
Exterior of diameter of ditto
0
21
0
%
0
8 at 14
2
-
127 at 2
0 2
& at
Thickness of tubes.-Wire gage
No. 14
No. 14
No. 14
No. 14
No. 12
No. 14
Distance from centre to centre of tubes
0 3
0
24
0 21
0 24
0 21
0 of
Diameter of steam-dome (inside)
1
5
1 7
Height of ditto
2 71
2 74
Diameter of safety-valves
2j&3
34 & 34
4&4
4&4
31&34
4&3
Diameter of inside copper steam-pipe
0
5
0
5
0 61
0 61
0 61
0 61
Thickness of ditto.-Wire gage
No. 10
No. 10
No. 10
No. 10
Diameter of branch steam-pipe (inside)
0
3f
0
31
0
4}
0 4f
0
41
0 41
Diameter of top of blast-pipe (inside)
0
21
0
21
0
3
0 3
0
3f
0 3
Diameter of cylinders
1
of
1
0
1 2
1 2
1 3
1 2
Length of stroke
1 6
1
6
1 6
1 6
1 6
1 6
Distance of centres of cylinders
2 5
2
5
2 5
2 5
3 0
2 5
Size of steam-ports
11 x 1
of
x
1
11
11 If
11 11
11 11
Size of eduction-ports
11 x 2
91
X
8
11 21
11 st
11
11
Breadth of bridge between ports
0 01
0
04
0 01
0 of
0 of
0 of
Lead of slide-valves
0
0,10
0
of
0 0.3
0 03
0 0,3 16
Cover of ditto
0
0,2
0
of
0 of
0 of
0 01
0 0,8 16
Distance from centre of cylinder to centre of
steam-chest
0 11
1 of
1 04
1 2
1 04
Thickness of piston
3f
3f
4
4.
4
#
Diameter of piston-rod
2
2
2
2
21
2
Diameter of valve-spindle
of
1
1
1
If
1
Diameter of pump-ram
1f
2
2
2
2t
2
Length of pump-lever
61
None
64
67
None
6
Diameter of bali-valves
2
2
27
277
2f
2
10
Diameter of union and section pipes (inside)
11
11
11
14
21
11
Diameter of driving-wheels
5 6
6
0
5 0
6 0
7 0
4 6
Tyres of ditto in centre of tread
6 x 11
7x11
7X11
51X2
51x11
Diameter of leading-wheels
3 9
4
0
5 0
4 of
4 0
4 6
Tires of ditto
5f x 11
6x11
6X0
51X2
5+X11
Diameter of trailing-wheels
3 9
4
0
3 6
4 0
4 0
None
Tires of ditto
5f
x
11
6x11
6x11
54X2
Diameter of plain part of cranked axle
41
5
5f
51
6f
5'
Diameter of inside bearings
5
5
52
51
of
5f
Length of ditto
3j&3
3
31&3
3j&3
4
3
Radius of ditto
9
3 &2f
21
51
Diameter of crank-pins
5
5
54
51
61
5
Length of ditto
3
3
3
3
4
3
Radius of ditto
21
21
29
2
51
6
Diameter of outside bearings
34
34
34
34
4
31
Length of ditto
51
5f
51
5¥
64
51
Diameter of bosses on axles for eccentrics
6J&4
5 & 5
7&51
7X51
7}&6f
7X51
Diameter of bosses for driving-wheels
64
64
64
61
71
64
Length of bosses for ditto
7.
7j
8f
77
71
Diameter of axle for leading-wheels
34
4
5
4f
6j&44
41
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ENGINES, RULES FOR CALCULATING THE PARTS OF.
527'
TABLE OF DIMENSIONS OF THE PARTS OF LOCOMOTIVE ENGINES-(Continued.)
RAILWAYS.
Bordeaux and
North Mid-
Northern
Great
Belgium.
La Teste.
land Cos.
and East-
Western.
Hartlepool.
ern Cos.
ft.
in.
?
in.
?
in.
ft.
in.
ft.
in.
ft.
in.
Dismeter of bearings for leading-wheels
3t
31
34
34
31
31
Length of bearings for ditto
51
5
51
51
61
5f
Diameter of boes for wheels
41
5
6f
5)
52
5f
Length of boss for ditto
64
7
81
71
8
Diameter of axle for trailing-wheels
34
4
44
41
61X41
Diameter of bearings
3+
34
34
31
3f
Length of bearings
5f
51
5f
51
64
Diameter of boss for wheels
41
5
5
51
54
Length of boes
64
7
8
71
8
Diameter of boes on axle for outside cranks
None
None
41
None
41
Length of ditto
31
34
Length of outside cranks from centre to centre
None
None
1
11
None
1
It
Diameter of plain pin on ditto
14
14
Length of plain pin
2
None
2
Diameter of ball pin
211
21
Outside frame (extreme breadth)
6
4
6
4
6
5
6 81
8
91
6
31
Length of ditto
18
3
18
21
18
3
18
21
20
4
18
3
Depth of frame sides
7
7
7t
7t
8
7t
Thickness of ditto
4
4
4
4
41
4
Thickness of side-plates
of
of
of
of
01
01
Thickness of horn-plates
of
of
of
of
of
of
Length of driving-wheel springs
2
8
2 9
2
9
2 6
Breadth of ditto
3f
3f
31
31
Number of plates
-
2at0f
1 at
1 at of
2at of
12at 04
12
at
14 at
10 at 0-3
Length of leading-wheel springs
Ellip.22
2 9
Ellip20
2 3
Breadth of ditto
3
4
3
34
{ 281015
1 at of
1 at of
2 at of
Number of plates
11at04
at 015
11 &t 0 5
10 at 0.5g
Length of trailing-wheel springs
Ellip.22
Ellip20
Ellip20
2 3
Breadth of ditto
3
3
3
34
-
2at015
1 at of
1 at
2 at of
Number of plates
8at04
6at015
6at5-50
8 at 0,5
Diameter of eccentrics
10f & 12f
10f
1 1
1 1
1 11
124X111
Throw of ditto
11
If
113
113
11
19
Breadth of ditto (brass hoops)
14
11
21
21
Iron 11
14
Diameter of valve-geer shafts
21
21
21
2t
21
21
Diameter of journals to ditto
11
11
11
14
2
11
Length of journal
21
2f
If
21
21
21
Length of side-levers
5
5
6
6
6f
6
Length of fork-end levers
6f
5
&
4116
6
6
54
6
Diameter of ferules
If
If
1f
If
11
2
Length of lifting levers
10
1
0
1 0
1 0
1 3
1 0
Length of reversing levers
12 & 10
1
0
12&10
12&10
1 3
1 0
Distance between motion bars
81
77
7
74
1 of
Diameter of ball on cross-head spindle
3
3
34
3t
3f
34
Diameter of connecting-rods in middle
21
24
at
21
21
Inside horn-bars
4 x 1
34 x
If
3fX14
31X11
4jX1j
31X11
Distance from centre of crank-axle to fire-box
1 6
1
6
1 6
1 6
1 5f
1 3
Distance from centre of crank-axle to centre of
leading-axle
5 6
6
%
5 6
5 7
6 7
5 10f
Distance from centre of crank-axle to centre of
trailing-axle
5 6
5
34
5 9
5 91
6 7
None
In the construction of the boilers for these engines, the cylindrical parts of each are fixed to the
smoke and fire-boxes, by 21 inch angle-irons round the upper, and 8 inch angle-irons round the lower
half of the boiler, firmly riveted with t of an inch rivets. The tops of the outside fire-boxes of the en-
gines for the North Midland, Northern and Eastern Counties, and the Great Western Railways, are
worked into a dome-shaped figure, by which means the advantage is obtained of placing the regulator,
with its appendages, immediately over the inside fire-box. The man-hole, being also placed in this
dome, admits of a free access to the interior of the boiler.
The outside fire-boxes for the engines of the Belgium railways, having low semicircular tops, the
steam domes are fixed on the cylindrical part of the boiler, and the regulators fixed to the tube-plate
of the smoke-box. The inside fire-boxes are formed of copper plates of the dimension shown; that por-
tion of the tube-plate, necessary for the insertion of the tubes, being increased in thickness in order to
increase its stability, as well as to assist in the more perfect securing of the tubes. The opening, in the
front plate for the smoke-box doors, is, in all respects, sufficiently large to admit of free working-room,
for the removal and reinstatement of the copper tubes of the boiler, as occasion may require.
In the inside fire-boxes of the engines for the Great Western Railway, there are low hollow parti-
tions, forming a clear water-space of four inches across the box; in the sides of this box, to which the
partition is riveted, apertures, eight by four inches, are cut 80 as to allow of the free escape of steam
from this division. The cylinders in the whole of the engines here enumerated are fixed in the lower
part of the cavity of the smoke-box, and firmly bolted to the front and back plates, these plates being
cut to receive the same. The pipes from the eduction ports (excepting in the engines for the Great
Digitized by Google
528
ENGINES, RULES FOR CALCULATING THE PARTS OF.
Western Railway) are cast on the body of the cylinders, and extending across towards the middle, and
uniting with its corresponding pipe, is strongly bolted thereto; on the upper surfaces of these pipes,
flanches are cast with a horizontal plane, upon which the blast-pipes are fixed. The blast-pipe of cop-
per, of a conical or pyramidal shape, formed with flanches at the bottom, is placed immediately over
the junction of the pipes from the eduction ports, and firmly bolted thereto.
The pumps are fixed either directly or indirectly to the outer bars of the inside framework, as the
shape and position of the parts may require; the rams of the engines for the Great Western Railway
are worked immediately from the spindle of the cross-head; those of the North Midland and the Bel-
gium engines, by an arm or lever attached to the piston-rod. The whole of the valve-geer, as well as
the carriages for the cross-head guide-bars are supported in their position by strong iron framework,
technically called horn-bars. These bars extend from: the back plate of the smoke-box to the front
plate of the outside fire-box, and are bolted to lugs fixed thereon to receive the ends of the bars. These
bars also serve the purpose of staying the crank axle by means of horns, which are worked on the bars,
and in which the bearings are fixed. The inner horn-bars of the engines for the North Midland, the
Belgium, and the North Eastern Railways, extend in a parallel direction, from the smoke-box to the
extreme length of the guide-bars; and from thence obliquely in a Y-shaped form, uniting with each
other, and forming, with the two outside horn-bars, a third stay to the crank axle.
The construction of the valve-geer of the engine for the Bordeaux and La Teste Railway, differs widely
in its details from the rest of the engines here noted. The eccentric bosses are placed close to each
other, in the middle of the driving-wheel axle, the end of each eccentric-rod being furnished with a pin
on which the ferules are placed, instead of forked ends, as have been hitherto generally adopted. On
the shaft which gives motion to the valve lever is fixed a double lever, with forked ends; in the hollow
of each fork a socket is formed for the reception of the pin and ferule on the end of the eccentric-rod;
and of such depth as to allow the lever to have a throw, variable from 4110 to 5 inches. Each of these
fork-ended levers are placed in a vertical position with each other, but acting in opposite directions upon
the inner end of the valve-shaft. The eccentric-rod ends are connected with a lever on the reversing
shaft, by lifting and lowering links, which not only admit of the eccentrics being thrown in or out of
geer, but also allow of a greater or less degree of travel to the side valve, by increasing or diminishing
the throw of the fork-ended lever. The peculiar advantage of the plan thus adopted is obvious from
the economy in the saving of steam, the travel of the slide being regulated 80 as to admit of no more
steam into the cylinder than what is necessary to propel the engine at the velocity required. The link
motion has, to a great extent, superseded the fork-ended levers, and it is a greatly preferable arrange-
ment.
RULES FOR THE CALCULATION OF THE PARTS OF MARINE ENGINES.
Rule 1.-To find the breadth of crank at paddle centre.-Multiply the square of the length of the
crank in inches by 1.561, and then multiply the square of the diameter of cylinder in inches by -1235
multiply the square root of the sum of these products by the square of the diameter of the cylinder in
inches; divide the product by 45; finally, extract the cube root of the quotient. The result is the
breadth of the web of crank at paddle centre.
EXAMPLE.
48 = length of crank in inches.
48
2304
1.561 = constant multiplier.
3596.5
5058
4102'3
64 = diameter of cylinder.
64
4096
1235 = constant multiplier.
5058
and 4102·3 = 64.05 nearly.
4096 = square of the diameter of the cylinder.
45) 2623485
5829.97
and 5829.97 = 18 nearly.
Rule 2.-To find the thickness of large eye of crank.-Multiply the square of the length of the crank
in inches by 1.561, and then multiply the square of the diameter of the cylinder in inches by 1235;
multiply the sum of these products by the square of the diameter of the cylinder in inches; afterwards,
divide the product by 182828; divide this quotient by the length of the crank in inches; finally, extract
the cube mot of the ouotient. The result is the proper thickness of the large eye of crank in inches.
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ENGINES, RULES FOR CALCULATING THE PARTS OF.
529
EXAMPLE.
48 = length of crank in inches.
48
2304
1.561 = constant multiplier.
85965
5058
41023
64 = diameter of cylinder in inches.
64
4096
1235 = constant multiplier.
5058
4102'3
4096 = square of diameter.
48) 16803020-8
182828) 350062.94
19147
and 2/191.47 = 577 nearly.
Rule 3.-To find the thickness of the web of crank at paddle-shaft contre.-Multiply the square of
the length of crank in inches by 1.561, and then multiply the square of the diameter in inches by 1235
multiply the square root of the sum of these products by the square of the diameter of the cylinder in
inches; divide this quotient by 360; finally, extract the cube root of the quotient. The result is the
thickness of the web of crank at paddle-shaft centre in inches.
Thus to apply the rule to the particular example which we have selected, we have
48 = length of crank in inches.
48
2304
1561 = constant multiplier.
3596.5
5058
4102'3
64 = diameter of cylinder.
64
4096
-1235 = constant multiplier.
5058
And V4102 8 = 6405 nearly
4096 = square of diameter.
360)2628485
72875
And 472875 = 9 nearly.
Rule 4.-To find the diameter of the paddle-shaft journal.-Multiply the square of the diameter of
cylinder in inches by the length of the crank in inches; extract the cube root of the product; finally,
multiply the result by -242. The final product is the diameter of the paddle-shaft journal in inches.
Rule 5.-To find the length of the paddle-shaft journal.-Multiply the square of the diameter of the
cylinder in inches by the length of the crank in inches; extract the cube root of the quotient; multiply
the result by 303. The product is the length of the paddle-shaft journal in inches. (The length of the
paddle-shaft journal is 11 times the diameter.)
Rule 6.-To find the diameter of crank-pin journal.-Multiply the diameter of the cylinder in inches
by 142. The result is the diameter of crank-pin journal in inches.
Rule 7.-To find the length of crank-pin journal.-Multiply the diameter of the cylinder in inches
by -16. The product is the length of the crank-pin journal in inches.
Rule 8.-7b find the breadth of the eye of cross-head-Multiply the diameter of the cylinder in inches
by 041. The product is the breadth of the eye in inches.
Rule 9.-To find the depth of the eye of cross-head-Multiply the diameter of the cylinder in inches
by 286. The product is the depth of the eye of cross-head in inches.
Rule 10.-To find the diameter of the journal of cross-head-Multiply the diameter of the cylinder in
inches by 086. The product is the diameter of the journal in inches.
Rule 11.-To find the length of the journal of cross-head-Multiply the diameter of the cylinder in
inches by 097. The product is the length of the journal in inches.
67
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530
ENGINES, RULES FOR CALCULATING THE PARTS OF.
Rule 12.-To find the thickness of the web of cross-head at middle.-Multiply the diameter of the
cylinder in inches by .072. The product is the thickness of the web of cross-head at middle in
inches.
Rule 13.-To find the breadth of web of cross-head at middle.-Multiply the diameter of the cylinder
in inches by 268. The product is the breadth of the web of cross-head at middle in inches.
Rule 14.-7o find the thickness of the web of cross-head at journal.-Multiply the diameter of the
cylinder in inches by 061. The product is the thickness of the web of cross-head at journal in inches.
Rule 15.-7o find the breadth of web of cross-head at journal.-Multiply the diameter of the cylinder
in inches by 101. The product is the breadth of the web of cross-head at journal in inches.
Rule 16.-7b find the diameter of the piston-rod-Divide the diameter of the cylinder in inches by
10. The quotient is the diameter of the piston-rod in inches.
Rule 17.-To find the length of the part of the piston-rod in the piston-Divide the diameter of the
cylinder in inches by 5. The quotient is the length of the part of the piston-rod in the piston in inches.
Rale 18.-To find the major diameter of the part of piston-rod in cross-head-Multiply the diameter
of the cylinder in inches by 095. The product is the major diameter of the part of piston-rod in cross-
head in inches.
'Rule 19.-To find the minor diameter of the part of piston-rod in cross-head-Multiply the diameter
of the cylinder in inches by 09. The product is the minor diameter of the part of piston-rod in cross-
head in inches.
Rule 20.-To find the major diameter of the part of piston-rod in piston-Multiply the diameter of
the cylinder in inches by 14. The product is the major diameter of the part of the piston-rod in piston
in inches.
Rule 21.-To find the minor diameter of the part of piston-rod in piston.-Multiply the diameter of
the cylinder in inches by 115. The product is the minor diameter of the part of piston-rod in piston.
Rule 22.-To find the depth of gibs and cutter through cross-head-Multiply the diameter of the
cylinder in inches by 105. The product is the depth of the gibs and cutter through cross-head.
Rule 23.-Tb find the thickness of the gibs and cutter through cross-head-Multiply the diameter of
the cylinder in inches by 021. The product is the thickness of the gibs and cutter through cross-head.
Rule 24.-To find the depth of cutter through piston.-Multiply the diameter of the cylinder in inches
by 085. The product is the depth of the cutter through piston in inches.
Rule 25.-To find the thickness of cutter through piston.-Multiply the diameter of the cylinder in
inches by 035. The product is the thickness of cutter through piston in inches.
Rule 26.-To find the diameter of connecting-rod at ends.-Multiply the diameter of the cylinder in
inches by 095. The product is the diameter of the connecting-rod at ends in inches,
Rule 27.-To find the major diameter of the part of connecting-rod in cross-tail.-Multiply the diam-
eter of the cylinder in inches by 098. The product is the major diameter of the part of connecting-rod
in cross-tail.
Rule 28.-To find the minor diameter of the part of connecting-rod in cross-tail.-Multiply the diam-
eter of the cylinder in inches by 09. The product is the minor diameter of the part of connecting-rod
in cress-tail in inches.
Rule 29.-Tp find the breadth of the butt.-Multiply the diameter of the cylinder in inches by .156
The product is the breadth of the butt in inches.
Rule 30.-To find the thickness of the butt.-Divide the diameter of the cylinder in inches by 8. The
quotient is the thickness of the butt in inches.
Rule 31.-To find the mean thickness of the strap at cutter.Multiply the diameter of the cylinder
in inches by 043. The product is the mean thickness of the strap at cutter.
Rule 32.-To find the mean thickness of the strap above cutter.-Multiply the diameter of the cylin-
der in inches by 032. The product is the mean thickness of the strap above cutter.
Rule 33.-To find the distance of cutter from end of strap.-Multiply the diameter of the cylinder in
inches by 048. The product is the distance of cutter from end of strap in inches.
Rule 34.-Tb find the breadth of the gibs and cutter through cross-tail.-Multiply the diameter of the
cylinder in inches by 105. The product is the breadth of the gibe and cutter through cross-tail.
Rule 35.-To find the breadth of the gibs and cutter through butt-Multiply the diameter of the cyl-
inder in inches by 11. The product is the breadth of the gibs and cutter through butt in inches.
Rule 36.-To find the thickness of the gibs and cutter through butt-Multiply the diameter of the
cylinder in inches by 029. The product is the thickness of the gibs and cutter through butt in inches.
Rule 37.-To find the breadth of the small eye of crank.-Multiply the diameter of the cylinder in
inches by 063. .The product is the proper breadth of the small eye of crank in inches.
Rade 38.-Tb find the length of the small eye of crank.-Multiply the diameter of the cylinder in
inches by 187. The product is the proper length of the small eye of crank.in inches.
Rule 39.-To find the thickness of the web of crank at pin centre.-Multiply the diameter of the cyl-
inder in inches. by 11. The product is the proper thickness of the web of crank at pin centre in inches.
Rule 40.-To find the breadth of the web of crank at pin centra-Multiply the diameter of the cylin-
der in inches by 16. The product is the proper breadth of crank at pin centre in inches.
Rule 41.-To find the diaméter of cylinder side-rods at ends.-Multiply the diameter of the cylinder
in inches by 065. The product is the diameter of the cylinder side-rods at ends in inches.
Digitized
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ENGINES, RULES FOR CALCULATING THE PARTS OF.
531
Rule 42.-To find the breadth of butt in inchea-Multiply the diameter of the cylinder in inches by
077. The product is the breadth of the butt in inches.
Rule 43.-7b find the thickness of the butt-Multiply the diameter of the cylinder in inches by .061.
The product is the thickness of the butt in inches.
Rule 44.-To find the mean thickness of strap at cutter. Multiply the diameter of the cylinder in
inches by 032. The product is the mean thickness of the strap at cutter.
Rule 45.-To find the mean thickness of strap below cutter.-Multiply the diameter of the cylinder in
inches by 023. The product is the mean thickness of strap below cutter in inches.
Rule 46.-To find the depth of gibs and cutter.-Multiply the diameter of the cylinder in inches by
08. The product is the depth of gibe and cutter in inches.
Rule 47.-7b find the thickness of gibs and cutter. Multiply the diameter of the cylinder in inches
by 016. The product is the thickness of the gibe and cutter in inches.
Rule 48.-To find the diameter of the main centre journal.-Multiply the diameter of the cylinder in
inches by 188. The product is the diameter of the main centre journal in inches.
Rule 49.-To find the length of the main centre journal.-Multiply the diameter of the cylinder in
inches by 275. The product is the diameter of the cylinder in inches.
Rule 50.-To find the depth of eye round end studs of lever.-Multiply the diameter of the cylinder in
inches by 074. The product is the depth of the eye round end studs of lever in inches.
Rule 51.-7b find the thickness of eye round end studs of lever-Multiply the diameter of the cylin-
der in inches by 052. The product is the thickness of eye round end studs of lever in inches.
Rule 52-To find the diamster of the end studs of laver.-Multiply the diameter of the cylinder in
inches by 07. The product is the diameter of the end studs of lever in inches.
Rule 58.-To find the length of the end studs of lever.-Multiply the diameter of the cylinder in inches
by 076. The product is the length of the end stude of lever in inches.
Rule 54.-To find the diameter of the air-pump studs.-Multiply the diameter of the cylinder in inches
by 045. The product is the diameter of the air-pump studs in inches.
Rule 55.-To find the length of the air-pump studs.-Multiply the diameter of the cylinder in inches
by 049. The product is the length of the air-pump studs in inches.
Rule 56.-To find the depth across the centre of the side lever.-Multiply the length of the side lever
in feet by 7423; extract the cube root of the product, and reserve the result for a multiplier. Then
square the diameter of the cylinder in inches; extract the cube root of the result. The product of the
final result and the reserved multiplier is the depth of the side lever in inches across the centre.
Rule 57.-To find the diameter of the air-pump.-Multiply the diameter of the cylinder in inches
by 6. The product is the diameter of the air-pump in inches.
Rule 58.-7b find the thickness of the eye of air-pump cross-head-Multiply the diameter of the cyl-
inder in inches by 025. The product is the thickness of the eye of air-pump cross-head in inches.
Rule 59.-7b find the depth of eye of air-pump cross-head-Multiply the diameter of the cylinder in
inches by 171. The product is the depth of the eye of air-pump cross-head in inches.
Rule 60.-To find the diameter of the journals of air-pump cross-head-Multiply the diameter of the
cylinder in inches by 051. The product is the diameter of the end journals.
Rule 61.-To find the length of the end journals for air-pump cross-head-Multiply the diameter of
the cylinder in inches by 058. The product is the length of the air-pump cross-head journals in inches.
Rule 62.-To find the thickness of the web of air-pump cross-head at middle.-Multiply the diameter
of the cylinder in inches by 048. The product is the thickness at middle of the web of air-pump cross-
head in inches.
Rule 63.-To find the depth at middle of the web of air-pump cross-head-Multiply the diameter of
the cylinder in inches by 161. The product is the depth at middle of air-pump cross-head in inches.
Rule 64.-7b find the thickness of the web of air-pump cross-head at journala.-Multiply the diame-
ter of the cylinder in inches by 087. The product is the thickness of the web of air-pump cross-head
at journals in inches.
Rule 65.-To find the depth of the air-pump cross-head web at journals.-Multiply the diameter of
the cylinder in inches by 061. The product is the depth at journals of the web of air-pump cross-head.
Rule 66.-To find the diameter of the air-pump piston-rod when of copper.-Multiply the diameter
of the cylinder in inches by 067. The product is the diameter of the air-pump piston-rod, when of cop-
per, in inchea.
Rule 67.-7b find the depth of gibs and cutter through air-pump cross-head-Multiply the diameter
of the cylinder in inches by 063. The product is the depth of the gibe and cutter through air-pump
cross-head in inches.
Rule 68.-7b find the thickness of the gibs and cutter through air-pump crose-head-Multiply the
diameter of the cylinder in inches by 013. The product is the thickness of the gibs and cutter in inches.
Rule 69.-7o find the depth of cutter through piston.-Multiply the diameter of the cylinder in
inches by 051. The product is the depth of the cutter through piston in inches.
Rule 70.-To find the thickness of cutter through air-pump piston-Multiply the diameter of the
cylinder in inches by 021. The product is the thickness of the cutter through air-pump piston.
Rule 71.-To find the diameter of air-pump side-rod at ends-Multiply the diameter of the cylinder
in inches by 039. The product is the diameter of the air-pump side-rod at ends in inches.
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Rule 72.-To find the breadth of butt for air-pump.-Multiply the diameter of the cylinder in inches
by 046. The product is the breadth of butt in inches.
Rule 73.-To find the thickness of butt for air-pump.-Multiply the diameter of the cylinder in
inches by 037. The product is the thickness of butt for air-pump in inches.
Rule 74.-To find the mean thickness of strap at cutter.-Multiply the diameter of the cylinder in
inches by -019. The product is the mean thickness of strap at cutter for air-pump in inches.
Rule 75.-To find the mean thickness of strap below cutter.-Multiply the diameter of the cylinder
in inches by 014. The product is the mean thickness of strap below cutter in inches.
Rule 76.-To find the depth of gibs and cutter for air-pump.-Multiply the diameter of the cylinder
in inches by 048. The product is the depth of gibe and cutter for air-pump in inches.
Rule 77.-To find the thickness of gibs and cutter for air-pump.-Divide the diameter of the cylin-
der in inches by 100. The quotient is the proper thickness of the gibs and cutter for air-pump in inches.
With regard to the following rule we may remark, that the area of the steam port ought to depend
principally upon the cubical content of the cylinder, which again depends entirely upon the product of
the square of the diameter of the cylinder and the length of the stroke of the engine. It is well known,
however, that the quantity of steam admitted by a small hole does not bear 80 great a proportion to
the quantity admitted by a larger one, as the area of the one does to the area of the other; and a cer-
tain allowance ought to be made for this. In the absence of correct theoretical information on this
point, we have attempted to make a proper allowance by supplying a constant; but of course this plan
ought only to be regarded as an approximation.
Rule 78.-To find the area of each steam port.-Multiply the square of the diameter of the cylinder
in inches by the length of the stroke in feet; multiply this product by 11 divide the last product by
1800; and, finally, to the quotient add 8. The result is the area of each steam port in square inches.
To show the use of this rule, we shall apply it to a particular example. We shall apply it to an
engine whose stroke is 6 feet, and diameter of cylinder 30 inches. Then, according to the rule, we have
30 = diameter of the cylinder in inches.
80
900 = square of diameter
6 = length of stroke in feet.
5400
11
59400 ÷ 1800 = 33
8 = constant to be added.
41 = area of steain port in square inches.
Rule 79.-To find the diameter of branch steam-pipe.-Multiply together the square of the diameter
of the cylinder in inches, the length of the stroke in feet, and 00498; to the product add 10-2, and ex-
tract the square root of the sum. The result is the diameter of the steam-pipe in inches.
Rule 80.-To find the diameter of waste-water pipe.-Multiply the square root of the nominal horse
power of the engine by 1.2. The product is the diameter of the waste-water pipe in inches.
Rule 81.-To find the area of foot-valve passage.-Multiply the nominal horse power of the engine
by 9; divide the product by 5; add 8 to the quotient. The sum is the area of foot-valve passage in
square inches.
Rule 82.-To find the area of injection-pipe.-Multiply the nominal horse power of the engine by
069 to the product add 2.81. The sum is the area of the injection-pipe in square inches.
Rule 83.-To find the diameter of feed-pipe.-Multiply the nominal horse power of the engine by 04;
to the product add 3; extract the square root of the sum. The result is the diameter of the feed-pipe
in inches.
Rule 84.-To find the diameter of waste-steam pipe.-Multiply the collective nominal horse power of
the engines by 375; to the product add 16875; extract the square root of the sum. The final result
is the diameter of the waste-steam pipe in inches.
Rule 85.-To find the diameter of the safety-valve when only one is used-To one-half the collective
nominal horse power of the engines add 225; extract the square root of the sum. The result is the
diameter of the safety-valve when only one is used.
Rule 86.-7b find the diameter of the safety-valve when two are used-Multiply the collective nominal
horse power of the engines by 25; to the product add 11-25; extract the square root of the sum. The
result is the diameter of the safety-valve when two are used.
Rule 87.-To find the diameter of the safety-valve when three are used-To one-sixth of the collective
nominal horse power of the engines add 7.5; extract the square root of the sum. The result is the
diameter of the safety-valve where three are used.
Rule 88.-To find the diameter of the safety-valve when four are used-Multiply the collective nomi-
nal horse power of the engines by 125; to the product add 5-625; extract the square root of the sum.
The result is the diameter of the safety-valve when four are used.
Another rule for safety-valves, and a preferable one for low pressures, is to allow 8 of a circular inch
of area per nominal horse power.
Rule 89.-To find the depth of the web at the centre of the main beam of a land engine.-Multiply
together the square of the diameter of the cylinder in inches, half the length of the main beam in feet,
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and the number 8; extract the cube root of the product. The result is the proper depth of the web of
the main beam across the centre in inches, when the main beam is constructed of cast-iron.
Rule 90.-7b find the depth of main beam at ends-Multiply together the square of the diameter of
the cylinder in inches, half the length of the main beam in feet, and the number 192; extract the cube
root of the product. The result is the depth in inches of the main beam at ends, when of cast-iron.
Rule 91.-To find the content of the feed-pump.-Multiply the square of the diameter of the cylinder
in inches by the length of the stroke in feet; divide the product by 30. The quotient is the content of
the feed-pump in cubic inches.
Rule 92.-To find the content of the cold-water pump.-Multiply the square of the diameter of the
cylinder in inches by the length of the stroke in feet; divide the product by 4400. The quotient is the
content of the cold-water pump in cubic feet.
Rule 93.-To find the thickness of the large eye of crank for fly-wheel shaft when of cast-iron.-
Multiply the square of the length of the crank in inches by 1.561, and then multiply the square of the
diameter of the cylinder in inches by 1235; multiply the sum of these products by the square of the
diameter of cylinder in inches; divide this product by 666-283; divide this quotient by the length of
the crank in inches; finally, extract the cube root of the quotient. The result is the proper thickness of
the large eye of crank for fly-wheel shaft in inches, when of cast-iron.
Rule 94.-To find the breadth of the web of crank at Ay-wheel shaft, when of cast-iron.-Multiply the
square of the length of the crank in inches by 1.561, and then multiply the square of the diameter of
the cylinder in inches by 1235; multiply the square root of the sum of these products by the square
of the diameter of the cylinder in inches; divide the product by 2304, and finally extract the cube root
of the quotient. The final result is the breadth of the crank at the centre of the fly-wheel shaft, when
the crank is of cast-iron.
As this rule is rather complicated, we shall illustrate it by showing its application to the particular
example of an engine whose stroke is 8 feet, and diameter of cylinder 64 inches. For this engine, fol-
lowing the directions of the rule, we have in succession,
64 = diameter of cylinder in inches.
64
4096 = square of the diameter of cylinder.
1235 = constant multiplier.
5058
48 = length of crank in inches
48
2304 = square of the length of crank.
1.561 = constant multiplier.
3596.5
5058
41028 = sum of products.
41028 = 64-05 nearly.
4096 = square of the diameter of cylinder.
constant divisor = 28-04)262348
11386.66 nearly.
and ¥11386.66 = 22:49.
Rule 95.-To find the thickness of the web of crank at centre of fly-wheel shaft, when of cast-iron.-
Multiply the square of the length of the crank in inches by 1.561, and then multiply the square of the
diameter of the cylinder in inches by 1235; multiply the square root of the sum of these products by
the square of the diameter of the cylinder in inches; divide this product by 184-32; finally, extract the
cube root of the quotient. The result is the thickness of the web of crank at the centre of the fly-wheel
shaft when of cast-iron, in inches.
As this rule is rather complicated, we shall illustrate it by applying it to the particular engine which
we have already selected. For this engine we have in succession,
48 = length of crank in inches.
48
2304 = square of the length of crank.
1561 = constant multiplier.
35965
64 = diameter of cylinder in inches.
64
4096 = square of the diameter of cylinder.
-1235 = constant multiplier.
5058
3596.5
4102'3 = sum of products.
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and 41023 = 64.05 nearly
4096 = square of diameter.
Constant divisor = 184-32)262348-5
1423'33
and V142833 = 11'25.
Rule 96.-To find the diameter of the fly-wheel shaft at smallest part, when it is of cast-iron-Multi-
ply the square of the diameter of the cylinder in inches by the length of the crank in inches; extract
the cube root of the product; finally multiply the result by 3025. The result is the diameter of the
fly-wheel shaft at smallest part in inches.
Rule 97.-7b find the sectional area of the rim of the fly-wheel, when of cast-iron.-Multiply together
the square of the diameter of the cylinder in inches, the square of the length of the stroke in feet, the
cube root of the length of the stroke in feet, and 6-125; divide the final product by the cube of the
diameter of the fly-wheel in feet. The quotient is the sectional area of the rim of fly-wheel in square
inches, provided it is of cast-iron.
As this rule is rather complicated, we shall endeavor to illustrate it by showing its application to a
particular engine. We shall apply the rule to determine the sectional area of the rim of fly-wheel for
an engine whose stroke is 8 feet, diameter of cylinder 50 inches; the diameter of the fly-wheel being 20
feet. For this engine we have as follows:
2500 = square of the diameter of cylinder.
64 = square of the length of stroke.
160000
2 = cube root of the length of stroke.
320000
6.125 = constant multiplier.
1960000
therefore sectional area in square inches = 1960000 ÷ 20' = 1960000 ÷ 8000 = 1960 ÷ 8 = 245.
In the following formula we denote the diameter of the cylinder in inches by D, the length of the
crank in inches by R, the length of the stroke in feet, and the nominal horse power of the engine by H.P.
Marine engines-Dimensions of several of the parts of the side-lever.
Depth of eye round end studs of lever = 074 X D.
Thickness of eye round end studs of lever = 052 X D.
Diameter of end studs, in inches = 07 X D.
Length of end studs, in inches = 076 X D.
Diameter of air-pump studs, in inches = 045 X D.
Length of air-pump studs, in inches = 049 X D.
Depth of cast-iron side-lever across centre, in inches = Di X (7423 X length of lever in feet)³.
Marine engine.-Dimensions of several parts of air-pump cross-head.
Diameter of air-pump, in inches = 6 X D.
Thickness of eye for air-pump rod, in inches = 025 X D.
Depth of eye for air-pump rod, in inches = 171 X D.
Diameter of end journals, in inches = 051 X D.
Length of end journals, in inches = 058 X D.
Thickness of web at middle, in inches = 043 X D
Depth of web at middle, in inches = 161 X D.
Thickness of web at journal = 037 X D.
Depth of web at journal = 061 X D.
Marine engine-Dimensions of the parts of air-pump piston-rod.
Diameter of air-pump piston-rod when of copper, in inches = 067 X D.
Depth of gibs and cutter through cross-head, in inches = 063 X D.
Thickness of gibs and cutter through cross-head, in inches = 013 X D.
Depth of cutter through piston, in inches = 051 X D.
Thickness of cutter through piston, in inches = 021 X D.
Marine engine.-Dimensions of the remaining parts of the air-pump machinery.
Diameter of air-pump side-rods at ends, in inches = 039 X D.
Breadth of butt, in inches = 046 X D.
Thickness of butt, in inches = 037 X D.
Mean thickness of strap at cutter, in inches = 019 X D.
Mean thickness of strap below cutter, in inches = 014 X D.
Depth of gibe and cutter, in inches = 048 X D.
Thickness of gibe and cutter, in inches = D ÷ 100.
Marine and land engines.-Area of steam ports.
Area of each steam port, in square inches = 11 X 1 X D' ÷ 1800 + 8.
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Marine and land engines-Dimensions of branch steam-pipes,
Diameter of each branch steam-pipe = 00498 X I X Dª + 10.2.
Marine engine.-Dimensions of several of the pipes connected with the engine.
Diameter of waste water-pipe, in inches = 1-2 X VH.P.
Area of foot-valve passage, in square inches = 1.8 X H.P.+ 8.
Area of injection-pipe, in square inches = 069 X H.P. + 281.
Diameter of feed-pipe, in inches
Diameter of waste steam-pipe, in inches = 375 X H. P. +
Marine and land enginea-Dimensions of safety-yalves.
Diameter of safety-valve, when one only is used = V5XH.P.225.
Diameter of safety-valve, when two are used = 25 X H. P. + 11-25.
Diameter of safety-valve, when three are used = X H. P. + 75.
Diameter of safety-valve, when four are used = X H. P. + 5-625.
Land engine.-Dimensions of main beam.
Depth of web of main beam across centre = V3 X D' X half length of main beam, in feet.
Depth of main beam at ends = 192 X Dª X half length of main beam, in feet.
Land and Marine-engines-Content of feed-pump.
Content of feed-pump, in cubic inches = Dª X l
Land engines.-Content of cold-water pump.
Content of cold-water pump, in cubic feet =
Land engines-Dimensions of crank.
Thickness of large eye of crank, in inches = VD' X (1-561 X R* 1235 D') ÷ (R 666-283.)
Breadth of web of crank at fly-wheel shaft centre, in inches =
X 1235 X D')÷
Thickness of web of crank at fly-wheel shaft centre, in inches =
(1.561 X R² 1235 D')
Land engines-Dimensions of fly-wheel shaft.
Diameter of fly-wheel shaft, when of cast-iron, = 3025 X VR X Dª.
DIMENSIONS OF PA : # OF LOCOMOTIVES.
Diameter of cylinder.-In locomotive engines the diameter of the cylinder varies less than in either
the land or the marine engine. In few of the locomotive engines at present in use is the diameter of
the cylinder greater than 18 inches, or less than 12 inches. The length of the stroke of nearly all the
locomotive engines at present in use is 18 inches, and there are always two cylinders, which are-gener-
ally connected to cranks upon the axle, standing at right angles with one another. Outside, cylinders,
operating upon pins in the driving-wheels, have latterly been largely introduced.
Area of induction ports.
Rule-To find the size of the steam ports for the locomotive engine.-Multiply the square of the
diameter of the cylinder by 068. The product is the proper size of the steam ports in square inches.
Example.-Required the proper size of the steam ports of a locomotive engine whose diameter is 15
inches. Here, according to the rule, size of steam ports = 068 X 15 X 15 = 068 X 225 = 153 square
inches, or between 151 and 15} square inches.
After having determined the area of the ports, we may easily find the depth when the length is
given, or, conversely, the length when the depth is given. Thus, suppose we know the length was 8
inches, then we find that the depth should be 158÷819125 inches, or nearly 2 inches; or suppose
we knew the depth was 2 inches, then we would find that the length was 153 ÷ 2 = 785 inches, or
nearly 74 inches.
Area of eduction ports.-The proper area for the eduction ports may be found from the following
rule.
Rule.-To find the area of the eduction ports-Multiply the square of the diameter of the cylinder in
inches by -128. The product is the area of the eduction ports in square inches.
Example.-Required the area of the eduction ports of a locomotive engine, when the diameter of the
cylinders is 18 inches. In this example we have, according to the rule, area of eduction part = 128 X
13" = 128 X 169 = 21632 inches, or between 211 and 211 square inches.
Breadth of bridge between ports.-The breadth of the bridges between the eduction port and the in-
duction ports is usually between t inch and 1 inch.
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Diameter of boiler.
Rule.-To find the inside diameter of the boiler-Multiply the diameter of the cylinder in inches by
8·11. The product is the inside diameter of the boiler in inches.
Example.-Required the inside diameter of the boiler for a locomotive engine, the diameter of the
cylinders being 15 inches.
In this example we have, according to the rule, inside diameter of boiler = 15 X 8'11 = 46-65 inches,
or about 3 feet 10g inches.
Length of boiler.-In the Northern and Eastern Counties Railway the length of the boiler is 8 feet;
while in the North Midland Counties Railway, in the Great Western Railway, and in the Hartlepool
Railway, the length of the boiler is 81 feet. In the Belgian railways the length of the boiler is 8 feet
2 inches. And in the Bordeaux and La Teste railway the length of the boiler is 8 feet 9 inches. In
Stephenson's locomotive engines, the length of the boiler is between 11 and 12 feet. In this country
the length is from 10 to 14 feet.
Diameter of steam dome inside.-It is obvious that the diameter of the steam dome may be varied
considerably, according to circumstances; but the first indication is to make it large enough. It is
usual, however, in practice, to proportion the diameter of the steam dome to the diameter of the cylin-
der; and there appears to be no great objection to this. The following rule will be found to give the
diameter of the dome usually adopted in practice.
Rule-To find the diameter of the steam dome-Multiply the diameter of the cylinder in inches by
148. The product is the diameter of the dome in inches.
Height of steam dome-The height of the steam dome may vary. Judging from practice, it appears
that a uniform height of 21 feet would answer very well
Diameter of safety-valve.-In practice the diameter of the safety-valve varies considerably. The fol-
lowing rule gives the diameter of the safety-valve usually adopted in practice.
Rule-To find the diameter of the safety-valve.-Divide the diameter of the cylinder in inches by 4.
The quotient is the diameter of the safety-valve in inches.
Example.-Required the diameter of the safety-valves for the boiler of a locomotive engine, the
diameter of the cylinder being 18 inches. Here, according to the rule, diameter of safety-valve = 13 ÷
4 = 34 inches. A larger size, however, is preferable, as being less likely to stick.
Diameter of valve spindle.-The following rule will be found to give the correct diameter of the valve
spindle. It is entirely founded on practice.
Rule-To find the diameter of the valve spindle.-Multiply the diameter of the cylinder in inches by
076. The product is the proper diameter of the valve spindle.
Example-Required the diameter of the valve spindle for a locomotive engine whose cylinders'
diameters are 18 inches.
In this example we have, according to the rule, diameter of valve spindle = 13 X 076 = 988 inches,
or very nearly 1 inch.
Diameter of chimney.-It is usual in practice to make the diameter of the chimney equal to the
diameter of the cylinder. Thus, a locomotive engine whose cylinders' diameters are 15 inches would
have the inside diameter of the chimney also 15 inches, or thereabouts. This rule has, at least, the
merit of simplicity.
Area of fire-grate.-The following rule determines the area of the fire-grate usually given in practice.
We may remark, that the area of the fire-grate in practice follows a more certain rule than any other part
of the engine appears to do; but it is in all cases much too small, and occasions a great loss of power
by the urging of the blast it renders necessary, and a rapid deterioration of the furnace plates from ex-
cessive heat. There is no good reason why the furnace should not be nearly as long as the boiler it
would then resemble the furnace of a marine boiler, and be as manageable.
Rule.-To find the area of fire-grate.-Multiply the diameter of the cylinder in inches by 77. The
product is the area of the fire-grate in superficial feet.
Example-Required the area of the fire-grate of a locomotive engine, the diameters of the cylinders
being 15 inches.
In this example we have, according to the rule, area of fire-grate = 77 X 15 = 11.55 square feet,
or about 11} square feet. Though this rule, however, represents the usual practice, the area of fire-
grate should not be contingent upon the size of the cylinder, but upon the quantity of steam to be
generated.
Area of heating surface.-In the construction of a locomotive engine, one great object is to obtain a
boiler which will produce a sufficient quantity of steam with as little bulk and weight as possible. This
object is admirably accomplished in the construction of the boiler of the locomotive engine. This little
barrel of tubes generates more steam in an hour than was formerly raised from a boiler and fire occu-
pying a considerable house. This favorable result is obtained simply by exposing the water to a greater
amount of heating surface.
In the usual construction of the locomotive boiler, it is obvious that we can only consider four of the
six faces of the inside fire-box as effective heating surface; viz., the crown of the box, and the three per-
pendicular sides. The circumferences of the tubes are also effective heating surface; 80 that the whole
effective heating surface of a locomotive boiler may be considered to be the four faces of the inside fire-
box, plus the sum of the surfaces of the tubes. Understanding this to be the effective heating surface,
the following rule determines the average amount of heating surface usually given in practice.
Rule-To find the effective heating surface.-Multiply the square of the diameter of the cylinder in
inches by 5; divide the product by 2. The quotient is the area of the effective heating surface in square ft.
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Example.-Required the effective heating surface of the boiler of a locomotive engine, the diameters
of the cylinders being 15 inches.
In this example we have, according to the rule, effective heating surface = 15' X 5 ÷ 2 = 225 X 5
÷ 2 = 1125 ÷ 2 = 5621 square feet.
According to the rule which we have given for the fire-grate, the area of the fire-grate for this boiler
would be about 11} square feet. We may suppose, therefore, the area of the crown of the box to be
12 square feet. The area of the three perpendicular sides of the inside fire-box is usually three times
the area of the crown; 80 that the effective heating surface of the fire-box is 48 square feet. Hence
the heating surface of the tubes = 526.5 48 = 4785 square feet. The inside diameters of the tubes
are generally about 11 inches; and therefore the circumference of a section of these tubes is 5.4978
inches. Hence, supposing the tube to be 81 feet long, the surface of one = 5.4978 X 81 ÷ 12 =
-45815 X 81 = 3.8943 square feet. And, therefore, the number of tubes = 4785 ÷ 3.8943 = 123
nearly.
Area of water-level.-This of course varies with the different circumstances of the boiler. The aver-
age area may be found from the following rule.
Rule-To find the area of the water-level.-Multiply the diameter of the cylinder in inches by 208.
The product is the area of the water-level in square feet.
Example-Required the area of the water-level for a locomotive engine, whose cylinders' diameters
are 14 inches.
In this case we have, according to the rule, area of water-level = 14 X 2-08 = 29-12 square feet.
Cubical content of water in boiler.-This of course varies not only in different boilers, but also in the
same boiler at different times. The following rule is supposed to give the average quantity of water
in the boiler.
Rule.-To find the cubical content of the water in the boiler.-Multiply the square of the diameter of
the cylinder in inches by 9; divide the product by 40. The quotient is the cubical content of the water
in the boiler in cubic feet.
Example.-Required the average cubical content of the water in the boiler of a locomotive engine,
the diameters of the cylinders being 14 inches.
In this example we have, according to the rule, cubical content of water = 9 X 14" ÷ 40 = 44.1
cubic feet.
Content of feed-pump.-In the locomotive engine, the feed-pump is generally attached to the cross-
head, and consequently it has the same stroke as the piston. As we have mentioned before, the stroke
of the locomotive engine is generally in practice 18 inches. Hence, assuming the stroke of the feed-
pump to be constantly 18 inches, it only remains for us to determine the diameter of the ram. It may
be found from the following rule.
Rule.-To find the diameter of the feed-pump ram-Multiply the square of the diameter of the cylin-
der in inches by -011. The product is the diameter of the ram in inches.
Example-Required the diameter of the ram for the feed-pump for a locomotive engine whose diam-
eter of cylinder is 14 inches.
In this example we have, according to the rule, diameter of ram = -011 X 14" = -011 X 196 = 2-156
inches, or between 2 and 21 inches.
Cubical content of steam room-The quantity of steam in the boiler varies not only for different
boilers, but even for the same boiler in different circumstances. But when the locomotive is in motion,
there is usually a certain proportion of the boiler filled with the steam. Including the dome and the
steam-pipe, the content of the steam room will be found usually to be somewhat less than the cubical
content of the water. But as it is desirable that it should be increased, we give the following rule.
Rule-To find the cubical content of the steam room.-Multiply the square of the diameter of the
cylinder in inches by 9; divide the product by 40. The quotient is the cubical content of the steam
room in cubic feet.
Example.-Required the cubical content of the steam room in a locomotive boiler, the diameters of
the cylinders being 12 inches.
In this example we have, according to the rule, cubical content of steam room = 9 X 12* ÷ 40 =
9 X 144 ÷ 40 = 32.4 cubic feet.
Cubical content of inside fire-box above fire-bars.-The following rule determines the cubical content
of fire-box usually given in practice.
Rule-To find the cubical content of inside fire-box above fire-bare-Divide the square of the diam-
eter of the cylinder in inches by 4. The quotient is the content of the inside fire-box above fire-bars in
cubic feet.
Example.-Required the content of inside fire-box above fire-bars in a locomotive engine, when the
diameters of the cylinders are each 15 inches.
In this example we have, according to the rule, content of inside fire-box above fire-bars = 15" ÷ 4 =
225 ÷ 4 = 561 cubic feet.
Thickness of the plates of boiler.-In general the thickness of the plates of the locomotive boiler is
9-32 inch, or No. 3 wire gage.
Inside diameter of steam-pipe.-The diameter usually given to the steam-pipe of the locomotive en-
gine may be found from the following rule.
Rule-To find the diameter of the steam-pipe of the locomotive engine.-Multiply the square of the
diameter of the cylinder in inches by 03. The product is the diameter of the steam-pipe in inches.
Example-Required the diameter of the steam-pipe of a locomotive engine, the diameter of the
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cylinder being 13 inches. Here, according to the rule, diameter of steam-pipe = 03 X 18" 03 X 169
=5.07 inches; or a very little more than 5 inches. The steam-pipe is usually made too small in en-
gines intended for high speeds.
Diameter of branch steam-pipes.-The following rule gives the usual diameter of the branch steam-
pipe for locomotive engines.
Rule-To find the diameter of the branch steam-pipe for the locomotive engine.-Multiply the square
of the diameter of the cylinder in inches by 021. The product is the diameter of the branch steam-
pipe for the locomotive engine in inches.
Example.-Required the diameter of the branch steam-pipes for a locomotive engine, when the cylin-
ders' diameter is 15 inches. Here, according to the rule, diameter of branch pipe = 021 X 152 = 021
X 225 = 4725 inches, or about 41 inches.
Diameter of top of blast-pipe-The diameter of the top of the blast-pipe may be found from the fol-
lowing rule.
Rule.-To find the diameter of the top of the blast-pipe.-Multiply the square of the diameter of the
cylinder in inches by 017. The product is the diameter of the top of the blast-pipe in inches.
Example.-The diameter of a locomotive engine is 13 inches; required the diameter of the blast-pipe
at top. Here, according to the rule, diameter of blast-pipe at top= .017 X 13 = 017 X 169 = 2.878
inches, or between 21 and 3 inches; but the variable exhaust is now generally used.
Diameter of feed-pipes-There appear to be no theoretical considerations which would lead us to de-
termine exactly the proper size of the feed-pipes. Judging from practice, however, the following rule
will be found to give the proper dimensions.
Rule-To find the diameter of the foed-pipes-Multiply the diameter of the cylinder in inches by
-141. The product is the proper diameter of the feed-pipes.
Example-Required the diameter of the feed-pipes for a locomotive engine, the diameter of the
cylinder being 15 inches.
In this example we have, according to the rule, diameter of feed-pipe = 15 X 141 = 2-115 inches,
or between 2 and 21 inches.
Diameter of piston-rod-The diameter of the piston-rod for the locomotive engine is usually about
one-seventh the diameter of the cylinder. Therefore,
Rule-To find the diameter of the piston-rod for the locomotive engine.-Divide the diameter of the
cylinder in inches by 7. The quotient is the diameter of the piston-rod in inches.
Example.-The diameter of the cylinder of a locomotive engine is 15 inches, required the diameter of
the piston-rod. Here, according to the rule, diameter of piston-rod = 15 ÷ 7 = 21 inches.
Thickness of piston-The thickness of the piston in locomotive engines is usually about two-sevenths
of the diameter of the cylinder. Therefore,
Rule-To find the thickness of the piston in the locomotive engine.-Multiply the diameter of the
cylinder in inches by 2; divide the product by 7. The quotient is the thickness of the piston in
inches.
Example.-The diameter of the cylinder of a locomotive engine is 14 inches, required the thickness
of the piston. Here, according to the rule, thickness of piston = 2 X 14 ÷ 7 =4 inches.
Diameter of connecting-rods at middle.-The following rule gives the diameter of the connecting-rod
at middle. The rule is entirely founded on practice.
Rule.-To find the diameter of the connecting-rod at middle of the locomotive engine.-Multiply the
diameter of the cylinder in inches by -21. The product is the diameter of the connecting-rod at middle
in inches.
Example.-Required the diameter of the connecting-rods at middle for a locomotive engine, the
diameter of the cylinders being 12 inches.
For this example we have, according to the rule, diameter of connecting-rods at middle = 12 X -21 =
2.52 inches, or 21 inches.
Diameter of ball on cross-head spindle.-The diameter of the ball on the cross-head spindle may be
found from the following rule.
Rule-To find the diameter of the ball on cross-head spindle of a locomotive engine.-Multiply the
diameter of the cylinder in inches by 23. The product is the diameter of the ball on the cross-head
spindle.
Example.-Required the diameter of the ball on the cross-head spindle of a locomotive engine, when
the diameter of the cylinder is 15 inches. Here, according to the rule, diameter of ball = .23 X 15 =
3.45 inches, or nearly sh inches.
Diameter of the inside bearings of the crank-axle.-It is obvious that the inside bearings of the crank-
axle of the locomotive engine correspond to the paddle-shaft journal of the marine engine, and to the
fly-wheel shaft journal of the land engine. We may conclude, therefore, that the proper diameter of
these bearings ought to depend jointly upon the length of the stroke and the diameter of the cylinder.
In the locomotive engine the stroke is usually 18 inches, 80 that we may consider that the diameter of
the bearing depends solely upon the diameter of the cylinder. The following rule will give the diam-
eter of the inside bearing.
Rule-To find the diameter of the inside bearing for the locomotive engine.-Extract the cube root
of the square of the diameter of the cylinder in inches; multiply the result by 96. The product is the
proper diameter of the inside bearing of the crank-axle for the locomotive engine.
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Diameter of plain part of crank-axle.-It is usual to make the plain part of crank-axle of the same
sectional area as the inside bearings.
Rule-To determine the diameter of the plain part of crank-axle for the locomotive engine.-Extract
the cube root of the square of the diameter of the cylinder in inches multiply the result by 96. The
product is the proper diameter of the plain part of the crank-axle of the locomotive engine in inches.
Diameter of the outside bearings of the crank-axle.-The crank-axle, in addition to resting upon the
inside bearings, is sometimes also made to rest partly upon outside bearings. These outside bearings
are added only for the sake of steadiness, and they do not need to be so strong as the inside bearings.
The proper size of the diameter of these bearings may be found from the following rule.
Rule-To find the diameter of outside bearings for the locomotive engina-Multiply the square of
the diameter of the cylinders in inches by 396; extract the cube root of the product. The result is the
diameter of the outside bearings in inchea.
Diameter of crank-pin-The following rule gives the proper diameter of the crank-pin. It is obvious
that the crank-pin of the locomotive engine is not altogether analogous to the crank-pin of the marine
or land engine, and, like them, ought to depend upon the diameter of the cylinder, as it is usually formed
out of the solid axle.
Rule-To find the diameter of the crank-pin for the locomotive engine-Multiply the diameter of the
cylinder in inches by 404. The product is the diameter of the crank-pin in inches.
Example.-Required the diameter of the crank-pin of a locomotive engine whose cylinders' diameters
are 15 inches.
In this example we have, according to the rule, diameter of crank-pin = 15 X 404 = inches, or
about 6 inches.
Length of crank-pin-The length of the crank-pin usually given in practice may be found from the
following rule.
Rule.-To find the length of the crank-pin.-Multiply the diameter of the cylinder in inches by 283.
The product is the length of the crank-pins in inches.
The part of the crank-axle answering to the crank-pin is usually rounded very much at the corners,
both to give additional strength, and to prevent side play.
These, then, are the chief dimensions of locomotive engines, according to the practice most generally
followed. The establishment of express trains and the general exigencies of steam locomotion are daily
introducing innovations, the effect of which is to make the engines of greater size and power; but it
cannot be said that a plan of locomotive engine has yet been contrived that is free from grave objec-
tions. The most material of these defects is the necessity that yet exists of expending a large propor-
tion of the power in the production of a draft; and this evil is traceable to the inadequate area of the
fire-grate, which makes an enormous rush of air through the fire necessary to accomplish the combustion
of the fuel requisite for the production of the steam. To gain a sufficient area of fire-grate an entirely
new arrangement of engine must be adopted; the furnace must be greatly lengthened, and perhaps it
may be found that short upright tubes may be introduced with advantage. Upright tubes have been
found to be more effectual in raising steam than horizontal tubes; but the tube-plate in the case of
upright tubes would be more liable to burn.
We here give the preceding rules in formulæ, in the belief that those well acquainted with algebraic
symbols prefer to have a rule expressed as a formula, as they can thus see at once the different
operations to be performed. In the following formulas we denote the diameter of the cylinder in
inches by D.
Locomotive engine.-Parts of the cylinder.
Area of induction-porta, in square inches = 068 X D'.
Area of eduction-ports, in square inches 128 X D'.
Breadth of bridge between ports between t inch and 1 inch.
Locomotive engine.-Parts of boiler
Diameter of boiler, in inches 3'11 X D.
Length of boiler between 8 feet and 12 feet.
Diameter of steam dome inside, in inches = 143 X D.
Height of steam dome feet.
Diameter of safety-valve, in inches = D÷4.
Diameter of valve-spindle, in inches X D.
Diameter of chimney, in inches D.
Area of fire-grate, in square X D.
Area of heating-surface, in square feet = 5 X D' ÷
Area of water-level, in square feet 2.08 X D.
Cubical content of water in boiler, in cubic feet = X ÷
Diameter of feed-pump ram in inches 011 X D'.
Cubical content of steam room, in cubic feet X D'÷40.
Cubical content of inside fire-box above fire-bars, in cubic feet = D' ÷
Thickness of the plates of boiler = i inch.
Locomotive engine.-Dimensions of several pipes.
Inside diameter of steam-pipe, in inches = 03 X Dª.
Inside diameter of branch steam-pipe, in inches = 021 X Dª.
Inside diameter of the top of blast-pipe 017 X D'.
Inside diameter of the feed-pipes= X D.
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Locomotive engines-Dimensions of several moving parts.
Diameter of piston-rod, in inches = D ÷ 7.
Thickness of piston, in inches = D ÷ 7.
Diameter of connecting-rods at middle, in inches = 21 X D.
Diameter of the ball on cross-head spindle, in inches = 23 X D.
Diameter of the inside bearings of the crank-axle, in inches = 96 X D'.
Diameter of the plain part of crank-axle, in inches = 96 X Dª.
Diameter of the outside bearings of the crank-axle, in inches = V.396 X Dª.
Diameter of crank-pin, in inches = 404 D.
Length of crank-pin, in inches 233 X D.
Expedients for regulating the velocity, and ascertaining the state and effective power of the engine.-
In most engines yet invented for developing mechanical effect from steam, there are great irregularities
in the velocity of the engine unless some contrivance be added to equalize the action of the steam. In
the land engine, and in the marine engine, the inequalities of velocity may be considered to proceed from
two sources; one, the unequal action of the mechanism of the engine itself, and the other the unequal
resistances which the engine has to overcome. The piston does not move with a uniform velocity up
and down the cylinder. The velocity is greatest at half stroke, and gradually decreases towards the
end of the stroke till it stops altogether, and finally returns in the opposite direction. When it is said
that the velocity of the piston is so many feet per minute, it is at once inferred that this can only be the
mean velocity, and that at the middle of the stroke the piston moves faster, and at the termination
slower, than the specified velocity. But even if the piston were to move uniformly, the intervention of
the crank would introduce irregularities into the velocity of the engine. The crank is certainly the best
constructive expedient yet devised for deriving a rotary motion from the reciprocating motion of the
piston; but, with all its advantages, it has the defect of not transmitting uniformly the pressure and
velocity of the engine. Let it not be inferred from this statement that we intend to show the least
favor to the exploded notion of the crank absorbing some of the power or mechanical effect of the steam.
The crank, like every other piece of machinery, transmits at every instant all the mechanical effect com-
municated to it; so that the only way in which we can suppose it to have an appetite for devouring
power is by taking into consideration the friction of the parts connected with it. But this is not incon-
sistent with our statement that the crank does not transmit the pressure and velocity of the piston
uniformly. The mechanical effect transmitted by the crank at any instant is measured by the product
of the effective pressure on the crank into its velocity at that instant; and this is exactly equal to the
mechanical effect generated at the piston at the same instant, as measured by the product of the
pressure on the piston into its velocity. But then the velocity of the crank does not always bear the
same proportion to the velocity of the piston, nor does the effective pressure on the crank always bear
the same proportion to the pressure on the piston. The products are constantly equal, but the pro-
portions of the elements constantly change; and the effect of the intervention of the crank, if unre-
dressed, would be to cause the velocity of the machinery driven by the engine to undergo inconvenient
fluctuations.
These irregularities proceeding from the internal mechanism of the engine itself would leave the mean
velocity unaffected. Supposing the amount of steam supplied, and the amount of resistance to be over-
come, to remain constant, then, although the velocity would be different for different positions of the
crank, still the average velocity throughout a whole revolution would remain constant. If, however, the
amount of resistance to be overcome be changed, the average velocity will also change, unless the
supply of steam be modified 80 as to suit the exigency. We may see the great variation of resistance
which a marine engine has to sustain in a storm. Sometimes the paddle-board is deeply immersed in
the wave-at other times it is almost completely out of the water; and in these circumstances it is
obvious that the average velocity of the paddle-shaft will vary. Analogous variations are experienced
in most of the applications of the land engine. If a land engine be employed to drive the machinery of
a cotton-mill, it will have to impart motion to all the spinning-frames in that mill. The operation of one or
more of these may from time to time be suspended, and consequently the moving power will be relieved
from a corresponding amount of resistance, and again the spinning-frames offer different resistances at
different times. These circumstances, it is obvious, must effect the mean velocity of the engine, unless
some contrivance be added to modify the supply of steam 80 as to correspond to the amount of resistance
to be overcome. If, under such circumstances, the energy of the moving power remains the same, the
velocity with which the machinery will be driven must be subject to variation, being increased whenever
the operation of any portion of the machines usually driven by it is suspended and, on the other hand,
diminished when any increased number of machines are brought into operation. In fine, the speed
will vary nearly in the inverse proportion of the load driven, increasing as the load is diminished, and
vice versa.
Now in most of the applications of the steam-engine, irregularity of velocity is considered to be a
great evil, and every exertion is made to lessen it as much as possible. Indeed, in all applications of
machinery it is desirable, all other things being equal, to have the motion uniform. On this Tredgold
remarks, very justly, An equable motion is desirable in almost every kind of machine, it being strained
much more by an irregular desultory one, as well as the fabric that supports it, than when the motion
is equable. The strength of the machine must be adapted to the greatest strains that occur; but the
quantity of work done is equivalent to the mean action only, and more is not performed by a desultory
motion than by one at a mean rate, and uniform." But uniformity of velocity is more sought after in
some of the applications of the steam-engine than in others. In the marine engine and the locomotive
engine all the requisite uniformity is obtained by attaching two engines to the main shaft, and so
adjusting them that the irregularities of the one engine partly counteract the irregularities of the other.
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The plan does not ensure perfect uniformity, but it approaches to it as far as particular circumstances
seem to require. In these engines no provision is made that the supply of steam should adapt itself to
the amount of resistance to be overcome. Again, in the common pumping-engine, there is not 80 much
urgent necessity for uniformity of motion as in most other applications of the land engine. Indeed,
judging from practice, we may infer that the advantage to be gained by a greater uniformity in the
velocity of the pumping-engine is not sufficiently great to compensate for the increased expense incurred
in providing and repairing a mechanism for redressing its inequalities. However, in many of the other
applications of the land engine, uniformity of velocity is the great object aimed at, and provision is made
for approximating to it as closely as possible.
We have pointed out two sources of irregularity of velocity; one the peculiar internal mechanism of
the engine itself, and the other the unequal resistances which it has to overcome. We proceed now to
mention in detail the several remedies that have been proposed for redressing these inequalities; and
first we proceed to mention those remedies which have been proposed for redressing the inequalities
arising from the peculiar mechanism of the engine itself.
Remedies for redressing the inequalities arising from the mechanism of the engine itself.-We
have already mentioned, that in the marine engine and locomotive engine an approximation to uni-
formity of velocity and uniformity of pressure is obtained by putting two engines upon the same
shaft, and 80 adjusting them that when the piston of the one engine is at its maximum velocity, the
piston of the other is at its minimum, and vice versa. This is effected by placing the cranks at right
angles to one another. The velocity obtained in this way is more nearly uniform than when only one
engine is used, but, unless assisted by a fly-wheel, the irregularities would be too great for many of the
nice applications of the modern steam-engine. Another objection to this plan is, that it requires two
engines, and thus takes up more room, and offers more constructive difficulties, than if the requisite
power were obtained from one engine only. These objections are to a certain extent obviated by an
ingenious plan first proposed by Mr. Mark Isambard Brunel, and for which he obtained a patent in 1828.
In his plan, instead of using two cranks, two cylinders are employed to give motion to the same crank.
This is effected by inclining the two cylinders to one another at an angle of about 90°, and causing
them to act upon the same axle by means of their connecting-rods. The frame of the engine is of the
form of an isosceles triangle. The working cylinders rest upon the inclined sides, and the main shaft
upon the apex of the triangle. The piston-rod is preserved in its rectilineal course by metal rollers
running upon guide-plates, which act a similar part to the vertical guides in the common direct-action
engine. Mr. Brunel states that the axis of the cylinders should be inclined to one another at an angle
of 102°; having, as he says, found that angle to be preferable to all others for transmitting a rotary
motion to the axle from the reciprocating motion of the pistons: but there seems to be no theoretical
considerations which would lead us to prefer an angle of 102° to an angle of 90°, except that the weight
of the pistons and their connections presses only in a downward direction. Underneath each of the
working cylinders is placed a small cylinder containing the valve. The valves are wrought by eccen-
trics from the main shaft, and the steam is alternately admitted into one end of the working cylinder,
and a passage opened for its escape at the other, as is the usual arrangement. From this form of con-
struction it follows, that when the piston of one of the cylinders is at half-stroke, the piston of the other
is at the termination of its stroke, or nearly 80; and thus the irregularities of the one cylinder partly
counteract the irregularities of the other. It is obvious, however, that this engine, whatever may be its
peculiar advantages in other respects, will fail in obtaining any greater regularity of velocity than is
obtained in the more usual construction, by placing two marine engines or two locomotive engines upon
the same shaft-a motion which of itself is too irregular for many of the modern applications of the
steam-engine.
When the expansive principle is employed in an engine, it involves the condition of a variation in the
intensity of the moving power. If the steam acts with a uniform energy on the piston as long as the
supply from the boiler continues, 80 soon as that supply is stopped by closing the steam-valve, the steam
contained in the cylinder will fill a gradually increasing volume by the motion of the piston, and con-
sequently will act above the piston with a gradually decreasing energy. Now, if the resistance to the
moving power be not subject to a variation corresponding exactly to this variation in the moving power,
the result will be that the motion will cease to be uniform. For if the momentum of the moving power
at any part of the stroke be greater than the resistance, the motion of the machinery will be accelerated;
and if it be less, the motion of the machinery will be retarded. Hence the application of the expansive
principle will introduce irregularities peculiar to itself. In the patent which Watt took out for the ap-
plication of the expansive principle, he specified several expedients for approximating to a uniform
effect upon a uniform resistance, notwithstanding the variation of the energy of the power which neces-
sarily attended the expansion of the steam. One method consisted in causing the moving force, when
acting with the greatest energy, to impart momentum to a mass of inert matter, which should be made
to restore the same force when the moving power was more enfeebled. Another expedient consisted
in causing the moving power, when acting with greatest energy, to lift a weight hung considerably
above the centre of the beam which should resist the ascent of the piston at the beginning of the stroke,
but aid its motion as soon as the beam passed the horizontal line, when the weight, like a tumbler,
would pass its centre of gravity. He also proposed to make the piston act on a lever, which should
have an arm of variable length, and so regulated, that when the momentum of the moving force in-
creased or diminished, the length of the arm diminished or increased in the same proportion. This last
expedient had been already applied in mechanics for the purpose of equalizing a varying power, and a
familiar example of its action occurs in the internal mechanism of a watch. When a watch is newly
wound up, the force of the spring is much greater than when the watch is nearly run down; so that if
the force of the spring always acted at the same leverage, a very unequal velocity would be produced.
The irregularity, however, is counteracted by the varying diameters of the grooves of the fusee, on
which the force of the spring, through the intervention of the chain, acts. As the watch goes down, the
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main-spring relaxes, and its force diminishes; but then the chain acts upon a wheel or circle having a
diameter increased in the same proportion as the strength of the spring is diminished. This expedient,
however, has never been successfully employed to regulate the action of the moving power of the steam-
engine; and it does not appear to be as practicable a scheme as that of hanging a weight above the
centre of the beam.
The following ingenious expedient for equalizing the action of the steam in the engine, was first, sug-
gested by Mr. Buckle, of Soho, and constructed by him for Mr. Lucy, of Birmingham. It acts upon the
principle of causing the engine to drag up a piston against the pressure of the atmosphere when the en-
ergy of the moving power is above the average; the power thus consumed being returned to the engine
by the atmosphere forcing down the piston when the energy of the moving power is below the average,
Fig. 1469. The manner in which this is accomplished may be easily understood from the accompanying
figure. P represents the piston in the cylinder, LL the great beam, LR the connecting-rod, RO the
crank, and R WWW a toothed wheel carried round by the crank. These are all the same as in the
common steam-engine. There is added r w to w, a smaller wheel, whose diameter is only one-half that
of the larger, and consequently it has only one-half the number of teeth. The small wheel will obvi-
ously perform a half revolution whilst the large wheel performs a quarter revolution. 11 is a second
1469.
L
L
W
R
W
lever, driven by the crank of the small wheel, to which it is attached by means of its connecting-rod.
The piston-rod l H is attached to the small lever 11, carrying with it a piston from top to bottom of an
open cylinder H. At the points marked 1, 2, 3, 4, the circumference of the great wheel is supposed to
be divided into four equal quadrants. Suppose now that the figure represents the state of the engine
when the piston is ascending. Whilst the crank moves from its present position to the position corre-
sponding to 2, the small wheel will have performed a semi-revolution, and the piston H will have
ascended to the top of the open cylinder, leaving a vacuum behind it. The piston H has been dragged
up against the pressure of the atmosphere, and this has consumed so much of the power of the engine.
This power, however, is not lost-it is only lent; for while the crank moves from the position 2 to the
position 3, the pressure of the air forces down the piston, and then the mechanical power is given back
to the large wheel. Again, whilst the crank moves from the position 3 to the position 4, the piston H
has to be dragged up to the top of the cylinder. Finally, whilst the crank moves from the position 4 to
the position 1, the pressure of the air forces down the piston of the open cylinder. Thus all the power
consumed in dragging up the piston against the pressure of the atmosphere, whilst the crank moves
from 1 to 2 and from 8 to 4, is faithfully given out to the wheel whilst the crank moves from 2 to 8 and
from 4 to 1. By this arrangement the engine is made to lay up, as it were, a store of power when the
moving force is acting with greatest energy, and this store is employed to assist it when the moving
force is acting with least energy. The pressure of the atmosphere is very adroitly converted into a
sort of reservoir, in which is deposited the surplus power generated while the crank moves from 1 to 2,
and from 3 to 4, to be withdrawn in order to supply the deficiency whilst the crank moves from 2 to 8
and from 4 to 1. Let A denote the number of square inches in the piston H, and h the number of feet
in the diameter of the small wheel; then the power necessary to drag the small piston from the bottom
of the cylinder to the top, exclusive of the friction, is represented by a mechanical effect of 15 X A X
h lb. raised one foot high. Hence, the total effect of this pneumatic pump is equivalent to causing the
engine to raise 15 X A X h lb. one foot high whilst the crank is passing the quadrantal points, and
allowing that weight to fall whilst the crank is passing the line of the centres. At the first considera-
tion we may perhaps infer that there would be a sudden change of velocity and pressure when the
small piston had arrived at the top or the bottom of its stroke; but a little more attention will convince
us that the change is gradually introduced by the peculiar relation of the wheels to one another. In
the position represented in the figure, the crank moves a certain distance past position 1 without raising
the piston to any great extent. As the crank descends to the quadrantal point, in which position most
power is generated, the crank of the small wheel descends to its quadrantal point, in which position the
pressure of the atmosphere on the piston H, offers the greatest resistance to the motion of the wheel.
After the large crank has passed its quadrantal point, the energy of the moving power begins to lessen,
and at the same time, the small crank having passed its quadrantal point, the motion of the small
wheel is less retarded by the pressure of the atmosphere on the piston H. When the large crank ap-
proaches to the position 2, the small crank approaches to the lowest part of its revolution, where the
pressure of the atmosphere on the piston H, offers little opposition to the motion of the small wheel.
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It is unnecessary to examine the action of the pump throughout the whole revolution of the wheel, as it
would be only a repetition of the process for a quadrant. But we see that, by the peculiar connection
of the wheel, the pressure of the atmosphere acts at one time as an accelerating force, at another as a
retarding force; that the change is not abrupt, but gradual; that it acts most efficiently as a retarding
force at the very moment that the energy of the moving force is greatest, viz., when the large crank is
passing the quadrantal points; and finally, it acts most efficiently as an accelerating force at the very
moment that the energy of the moving force is least, viz, when the crank is passing the line of the
centres. In fact, this pneumatic equalizer approaches more closely to theoretical perfection, than any
expedient ever proposed for equalizing the action of the engine. It may easily be shown that the
equalization of the effective pressure on the shafts is more efficient than that obtained by using a pair
of engines, and certainly it is much less complicated and expensive. The superiority is still more mani-
fest. when we consider the regularity of velocity which it in practice has been known to introduce.
The principal objection against the expedient is, that the toothed wheels are very bad constructive ex-
pedients, as they cause considerable friction, and the teeth are apt to break and to throw the whole into
disarrangement.
Several ingenious expedients have been proposed for enabling one shaft performing a certain number
of revolutions per minute to drive another shaft 80 as to make more revolutions per minute without con-
necting them together by tooth geering; but it would take up too much of our space to describe them
here. We may only refer to one which is applied in Smith's direct-action engine. This expedient
enables the main shaft to drive a second shaft with a double velocity the very thing which is required
for Buckle's pneumatic equalizer. We may remark that expedients for multiplying velocity are in-
vested with additional interest at present, from the introduction of the screw propeller. Before a suffi-
ciency of resistance can be obtained from the screw propeller, it must be made to perform more revo-
lutions per minute than the paddle-shaft, in the more common construction.
To demonstrate the practical efficiency of Buckle's equalizer, we may instance the great success
which has attended its application at a Birmingham flour-mill. So perfect was the action of this me-
chanism that the fly-wheel had been wholly removed, and the engine and the whole mill-work were
moving in the most smooth and effective manner. It was found that the change enabled them to give
all the grinding stones a greater velocity than formerly, so that the quantity ground was greater, in the
proportion of 56 to 52. and the quantity of the finest or first flour, from the same wheat, was likewise
much increased; 80 that, both by quantity and quality, the owner of the mill was now able to command
the market. The same motion has subsequently been applied to cotton-mills with perfect success, the
quality and the quantity of yarn produced being much improved.
The last expedient for equalizing the action of the steam which we shall notice, is that known as the fly-
wheel. The fly-wheel derives all its efficacy as an equalizer of the action of the steam from the principle,
that a large mass of matter offers great resistance to a change of motion. In a common double-action
engine, the steam loses all energy as a moving power for driving the machinery when the crank is pass-
ing the line of the centres, and a person not familiar with the laws of matter might conclude that the
engine would come to a stand-still, unless some moving foree was applied at these critical positions.
It is well known, however, that the momentum of the moving parts of the machinery will supply a
force sufficient to force the crank over the centre, although with a diminished velocity. The momentum
of the moving parts acts therefore to a certain extent as a regulator of the action of the steam, and the
addition of the fly-wheel only promotes regularity of velocity in so far as it increases this momentum.
The moving force of a body in motion is estimated by the product of its mass into its velocity. If,
therefore, we wish to regulate the velocity of an engine, by increasing the momentum of its moving
parts, we have only to connect with it some large mass that it moves with great velocity. Such a mass
is the fly-wheel: it is made of large diameter, 80 that its rim revolves with great rapidity; and the rim
is made of great weight, it being generally constructed of cast-iron. It is obvious that the same amount
of momentum may be obtained by other forms of construction; but the wheel possesses three advan-
tages peculiar to itself, which entitle it to the preference: it consumes no power by friction; it suffers
but little resistance to its motion from the air; and, finally, it can be so exactly poised on its axis as to
cause little strain on the machinery.
When the piston is at half-stroke, the energy of the moving force is at its maximum, 80 that at this
time more mechanical effect is generated than the usual resistance can appropriate. The surplus me-
chanical effect is expended in quickening the velocity of all the moving parts of the machinery. But
the greater the mass of a moving body, the more opposition does it offer to a change of motion; so that
the large mass of the fly-wheel absorbs the surplus mechanical effect without any great change of velo-
city. As the crank approaches the dead points, the effect of the moving power upon the axle and the
wheel is gradually enfeebled. The defect can only be supplied by abstracting some of the momentum
of the moving parts, and in these circumstances the large mass of the fly-wheel can give out the suffi-
cient quantity of momentum without any considerable change of velocity. The mass of the fly-wheel
is thus converted into a reservoir for receiving the surplus power at one time, and giving it out at
another. It is obvious, however, that the equalization of the motion produced by the fly-wheel is par-
tial, and can never be theoretically perfect. The fly-wheel acts as a receptacle of momentum, and as
matter can only receive momentum or give out momentum by a change of velocity, its agency as an
equalizer presupposes a slight change in the velocity of all the machinery. The motion of revolution
received by the main shaft is always subject to a variation corresponding to the amount of change of
momentum in the great mass of the fly-wheel sufficient to extricate the crank twice in every revolution
from its critical position while passing the line of centres; but this change can be rendered smaller and
smaller by increasing the weight and magnitude of the fly-wheel. Buckle's Pneumatic Equalizer acts
upon the principle of increasing or diminishing the resistance according as the energy of the moving
force increases or diminishes; the fly-wheel, on the other hand, acts upon the principle of increasing the
momentum of the moving parts of the machinery, so that when the energy of the moving force is greater
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or less than the resistance, the surplus may be absorbed or the defect supplied without any sensible
change in the motion of the whole. The former is capable of theoretical perfection; the latter must
necessarily fall short of that perfection, though it may be made sufficiently near it for practicable
purposes.
Fly-wheels are sometimes employed for other purposes than merely regulating the velocity of the
steam-engine. Whenever the employment of an engine is such that an enormous force is required to
act only for short times, such as when it is employed for rolling iron, or for stamping coins, then an
enormous fly-wheel is attached to the engine, which absorbs the power generated when the resistance is
removed, and gives it all the force at once at the proper moment. In these cases, the mass of the fly-
wheel rim is generally much greater than when the fly-wheel is only employed to regulate the velocity
in order that the momenta may be accumulated without inconveniently increasing the velocity. In some
cases the energy of the fly-wheel would be thirteen times greater than what the proportions given by
our rule would make it. Fly-wheels moving at a great velocity should always have malleable iron
arms, and the ring should be cast in a piece, and may be hooped with malleable iron with advantage.
Expedients for redressing the inequalities of velocity arising from the variation of resistance which
the engine has to overcome.-By the expedients which we have mentioned for equalizing the velocity of
the engine, the motion imparted to the main shaft will approximate to uniformity, provided that the
moving power of the engine be always proportionate to the load which the engine has to drive. But it
is obvious that in the general application of the steam-engine to the purposes of manufacture, provision
must be made for a considerable variation of the amount of resistance. If, while the amount of resistance
was changed, the energy of the moving power remained the same, then the velocity would also change,
increasing as the resistance diminished, and diminishing as the resistance increased. It is obvious that
an expedient for redressing the inequalities arising from this source may act upon the principle of regu-
dating the supply of steam from the boiler. The elastic force of the steam is the moving agent of the
whole machine; 80 that if we wish to keep the mean velocity constant, we must regulate the supply of
steam to the amount of resistance to be overcome. The simplest contrivance for this purpose is the
throttle-valve; so called from its agency in cutting off the supply of steam by throttling it in the steam-
pipe. It consists of an axis placed across the steam-pipe 80 as to form the diameter of a section of the
pipe, and on this axis is fixed a thin circular disk of nearly the same diameter as the inside diameter of
the steam-pipe; 80 that when the axis is turned to a certain position, the supply of steam is cut off alto-
gether. On one end of the axis is placed a short lever or handle, by which it can be turned in either
direction. When the handle is turned 80 that the plane of the disk is nearly at right angles to the direc-
tion of the steam-pipe, the passage within the pipe is closed altogether, and no steam can find admission
to the cylinder. On the other hand, when the handle is turned about a fourth of a complete revolution
from this position, the plane of the circular disk will then be in the direction of the length of the pipe, 80
as to offer little or no opposition to the passage of the steam. By turning the handle to any other
angle, the disk may be made to offer any required degree of opposition to the passage of the steam.
The form of the valve is obviously such, that, if constructed accurately, the pressure of the steam in
passing from the boiler will have no tendency to change any given position of the valve. If constructed
accurately, the quantity of surface on both sides of the axis is equal, and therefore the pressure of the
steam balances itself on the axis, 80 that it can have no tendency either to change the valve from its
existing position, or to oppose the effect of a pressure upon the handle. Any slight inaccuracy in the
construction of the valve, which would give the steam a capability of changing its position, would be
counteracted by the friction of the valve on its axis.
By this expedient the variations of the velocity of the engine, consequent upon the inequalities of
resistance which the engine has to overcome, may be remedied. If the load on the engine be lightened,
then, the supply of the steam continuing the same, the motion will be immediately accelerated; but the
tendency will be counteracted if the attendant workman turn round the handle, so as partially to close
the valve. If, on the other hand, the load on the engine be increased, then, the supply of the steam con-
tinuing the same, the motion will be immediately retarded. To counteract this, the attendant workman
must turn round the valve, 80 as to admit a greater supply of steam. By the adoption of these means the
mean velocity of the engine would be rendered uniform, provided the vigilance of the attendant work-
man were sufficient for the due management of the valve, and provided that the evaporating power of
the boiler continued in sufficient activity to supply the greatest amount of steam which would ever be
necessary for the maintenance of the mean velocity when the valve was fully open.
For some purposes engines are thus regulated by hand at the pleasure of the attendant workman. In
general, however, the proper manipulation of the handle is impracticable with any degree of vigilance
and skill which could be obtained from the person employed to attend the engine. Before the steam-
engine could be employed in those cases where great uniformity of velocity is required. it was necessary
that means should be found for enabling the engine itself properly to manipulate the valve without any
care or attention on the part of the attendant workman.
The governor.-In the mechanism of the governor as represented in Fig. 1470, EE represent two
heavy balls of iron, which are suspended from the point e by suitable arms. These bars cross one
another at e, forming a joint there, and are continued to f. At f these bars are joined by pivots to other
bars fh, which last fit into a ring or collar of metal at F, placed on the upright spindle, 80 as to be
capable of a motion upwards and downwards. The lever FG H rests upon a bar at G as fulcrum, and
is connected to the ring of metal at F by means of a forked end interposed between two collars on the
sliding piece. In this species of connection it is obvious that the ring of metal may revolve with the
spindle without moving the lever, but that it cannot move upwards or downwards on the spindle with-
out at the same time depressing or raising the remote extremity, H, of the lever. The bars E f pass
through slits in a metallic arch, which is firmly fixed to the upright spindle, 80 that the balls, the arms,
and the spindle must all revolve at the same time. If, now, the spindle be made in any manner what-
ever to revolve with a certain velocity, say thirty revolutions per minute, the balls EE will diverge from
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545
the spindle till their centrifugal force balances their weight. Let this be the position represented in the
figure. If the spindle be made to make more revolutions than 30, then the balls will diverge more
than what is represented in the figure. The points ff will diverge, and by means of the bars fh pull
down the one end F of the lever F H, and raise the other end H. This, by the mechanism represented
in the figure, would obviously tend to shut the valve, and to cut off the supply of steam. If, on the
other hand, the spindle be made to perform fewer revolutions per minute than 30, the balls will collapse
more than what is represented in the figure. The points ff will approach to one another, and by means
of the arms f h force up one end F of the lever, and depress the other end H. This will obviously tend
to open the valve, and to increase the supply of steam. After this action is understood, suppose that by
some mechanism the upright spindle is 80 connected with some moving part of the machinery, that when
the velocity of the engine is unduly accelerated, the spindle performs more than 80 revolutions, and
1470.
5
H
E
B
D
that when the velocity of the engine is unduly retarded, the spindle performs less than 80 revolutions
per minute, then this expedient becomes a regulator of all the inequalities of velocity arising from the
variations in the amount of resistance to be overcome. The upright spindle may be connected with the
fly-wheel shaft by means of an endless cord passing over a small grooved wheel d on the axis of the
spindle, and working into a similar groove on the fly-wheel shaft, or by geering, which is a preferable
mode in large engines. By properly proportioning the diameters of these wheels, the spindle may be
made to perform any number of revolutions per minute. It is obvious, that by these means the speed
of the grooved wheel d may be considered as representing the speed of the fly-wheel, and of the
machinery which the fly-wheel drives. After these observations, and the remarks upon the subject we
have already made, the principle which renders the governor so admirable a regulator of the velocity of
the machine will be easily apprehended. Let t denote the time in seconds of a periodic revolution of
the balls, and h the height in inches of e above the horizontal plane passing through the centre of the
balls; then, according to the well-known formula-
Let n denote the number of revolutions per minute, then we have the proportion-
<
60
31986
60
=
31986
h
or n = 18758 ÷ √h, which also may be written h = 35186 We have supposed Fig. 1470 to
represent the divergence of the balls when the spindle was making 30 revolutions per minute. In that
case n = 30, and h = 35186 ÷ 30' = 35186 ÷ 900 = 39.09 inches, or about 3910 inches. Now suppose
that the velocity of the engine was accelerated so much that the spindle performed 31 revolutions per
minute; then, taking n = 31, we obtain h = 35186 ÷ 31" = 35186 ÷ 961 = 36.61 inches, or somewhat
more than 361 inches. Thus, before the spindle can perform one more revolution per minute, the plane
of revolution of the balls rises 39 10 = 215 = inches, which obviously would cause a very
great change in the angle of divergence of the arms E ef. Suppose, on the other hand, that the velocity
of the engine were retarded 80 much that the spindle performed only 29 revolutions per minute. Then,
by taking n = 29, we find h = 35186 ÷ 20" = 35186 ÷ 841 = 41.84 inches, or between 411 and 42
inches. Thus, before the spindle can perform one less revolution per minute, the plane of revolution of
the balls must fall 41.84 391 = 2.74 = inches nearly, which would obviously cause the angle of
divergence of the arms E e to diminish very considerably. The efficiency of the governor in regulating
the supply of steam depends very much upon the mechanism employed to communicate its agency to
the throttle-valve. We may suppose the relations of the different bars E ef,fh, FGH, and 20, to be
such, that when the horizontal plane passing through the centre of the two balls EE is only 3661 inches
below the point of suspension e, the throttle-valve would entirely close up the steam-pipe, and that
when the horizontal plane passing through the centres of the two balls E E is 41.84 inches below the
point of suspension e, the throttle-valve would be fully open. On this supposition the effect of the
governor would be, that the engine could never be 80 much retarded as that the upright spindle per-
formed less than 29 revolutions per minute, or so much accelerated that the upright spindle performed
more than 31 revolutions per minute. This would ensure that the greatest change of velocity of any
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part of the machinery could never exceed of its mean velocity,-a variation which in practice
is scarcely perceptible; 80 that such a governor might be considered as practically perfect. In the best
modern engines the amount of variation is seldom less than one-tenth of the mean velocity. But we
may easily suppose the governor to be so connected with the engine as to act with even greater
efficiency than the one which we have described. The governor can be 80 proportioned, and 80 con-
nected with the engine, as to make 60 revolutions per minute; and the mechanism connecting it with
the throttle-valve may be 80 contrived, that when it makes 59 revolutions per minute the valve may be
fully open, and that when it makes 61 revolutions per minute the valve may be entirely closed. In this
case the greatest variation of the velocity of any part could never exceed one-thirtieth of the mean
velocity of that part. Indeed, in theory there is no limitation to the degree of regularity which may be
produced by the application of the governor. Practical considerations, however, limit the application
of the principle in several ways. It has been found inconvenient, for example, to allow minute altera-
tions of the governor to affect sensibly the position of the valve, and in order to prevent the incon-
venience arising from a continual changing in its position it is found expedient to construct the governor
such that even a considerable change in the divergence of the balls shall not produce too much alteration
in the opening of the valve. This consideration, and several others, limit the application of the
governing principle, and prevent engineers from approximating so closely to theoretical perfection, as
the principle permits.
In the construction of a governor to regulate a particular engine, it is necessary to consider the
position of the balls corresponding to the mean velocity of the engine, the range of motion which must
be given to the arms 80 as to enable them to confine the variations of velocity within certain limits, and
the weight of each of the balls. We proceed to consider each of these points separately.
Position of balls when moving with mean velocity.-To determine this position, we have only to con-
sider the vertical height of the point of suspension above the horizontal plane passing through the centre
of the balls when the spindle is making the average number of revolutions per minute. This is found
from the formula, 35186
From which we have the following rule:-
Rule-To determine the height of the point of suspension above the plane of the balls, when moving
with mean velocity.-Divide the number 35186 by the square of the mean number of revolutions per
minute. The quotient is the height of the point of suspension above the plane of the balls when moving
with mean velocity.
Example 1.-In a particular engine the governor is so connected with the fly-wheel shaft, that when
the engine is moving with average velocity the upright spindle makes 40 revolutions per minute. Required
the proper height of the point of suspension above the plane of the balls
In this example, 35186 35186 1600 35186 21.99 inches; so that the proper height is about
22 inches,
Example 2.-The governor spindle is driven by the fly-wheel shaft by means of an endless cord
passing over a groove on the spindle, and another groove on the fly-wheel shaft. The diameter of the
groove on the governor spindle is 9 inches, and the diameter of the groove on the fly-wheel shaft is 12
inches. The engine has a stroke of 8 feet, and the mean velocity of the piston is 256 feet per minute.
Required the proper height of the point of suspension above the plane of the balls.
In this example, since the mean velocity of the piston is 256 feet per minute, and the length of the
stroke 8 feet, it follows that the engine makes 256 8 = 32 single strokes, or 16 double strokes per
minute. The fly-wheel makes one revolution for each double stroke of the piston, and therefore the fly-
wheel also makes 16 revolutions per minute. The number of revolutions of the fly-wheel shaft is to the
number of the revolutions of the governor spindle inversely as the diameters of the grooves; 80 that we
have the proportion 9: = 9
Hence, according to the rule, 35186 (21f)2 35186 77.31 inches. This proportion is one never em-
ployed in practice on account of the inconvenience of the dimensions; but it is that proper to the data
assumed.
The range of motion of the arms.-This depends entirely upon the amount of variation of velocity
which may be permitted without detriment to the work upon which the engine is applied. We have
already shown, that when the governor performed on an average 30 revolutions per minute, a variation
of velocity equal to one-fifteenth of the mean velocity required only a range corresponding to a vertical
height of 523 (=41:84-86:61) inches. But we shall now conduct the inquiry in general terms.
Let
v = mean velocity of any moving part of the machinery.
n = number of revolutions of the governor spindle corresponding to v.
h = height of point of suspension above the plane of balls corresponding to v.
v + f v v = maximum velocity of any moving part of the machinery
h' = value of h corresponding to
I v = minimum velocity of any moving part of the machinery.
h₁ = value of h corresponding to velocity (1-fm) v.
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547
Then we wish to find the value of h₁ It is obvious that the value of n corresponding to the
maximum velocity will be and the value of n corresponding to the minimum velocity will
be Hence, according to the rule, 35186 35186 and therefore,
This formula is too complicated to be easily expressed in the form of a rule; but its applications may
easily be apprehended from the following example:
Example.-The governor of a steam-engine performs 80 revolutions per minute when the engine is
moving at the average speed. Required the range as expressed in vertical height of the arms of the
governor, such that the difference between the maximum and minimum velocity of any moving part
should never exceed one-fifteenth of the average velocity of that part.
In this example 1 and as we have shown previously, h
X
3909
inches.
We may conclude these investigations respecting the governor with a summary of the most important
points in the rationale of its operation. The governor may either be considered as a conical pendulum
compounded of the movements of two pendulums vibrating at right angles with one another, or it may
be viewed simply as a system of revolving balls, of which gravity is the centripetal force. In the
former case the governor will make half the number of revolutions that a pendulum of the same
vertical height makes of vibrations; and if the speed of the governor be urged beyond this point, the
arms will fly out and diminish the vertical height, until it just becomes equal to the length of a pendu-
lum that makes twice the number of vibrations in the minute that the governor makes of revolutions.
Every one knows that if the length of a pendulum be diminished, it will make a greater number of
vibrations in a given time than before; the cause of which simply is, that the steepness of the are in
which the ball of the pendulum descends is then increased, and it consequently descends with a greater
velocity. The length of the seconds' pendulum at the level of the sea in London is 39-1398 inches, and
the number of vibrations made in a given time by pendulums of different lengths varies inversely as the
square roots of their lengths. The proper speed for a governor, therefore, with a vertical height of about
39 inches, is 30 revolutions per minute, which accords with the preceding determinations; and similarly
if the vertical height of governor proper to any other number of revolutions be required, it is only
necessary to find the length of a pendulum, which will give twice the number of vibrations. If the
number of revolutions and the length of the arm be fixed, and it is wanted to know what is the diameter
of the circle described by the centre of the ball, it is necessary to find the vertical height by the fore-
going rule; or the following may be adopted. Divide the constant number 187.68 by the number of
revolutions per minute, and the square of the quotient will be the vertical height in inches of the centre
of suspension above the plane of the ball's revolution. Deduct the square of the vertical height in
inches from the square of the length of the arm in inches, and twice the square root of the remainder is
the diameter of the circle in which the centres of the balls revolve. The vertical height of the governor
is in every case taken as the distance between this circle and the point of suspension.
In considering the governor as a system of bodies acted upon by centrifugal and centripetal forces, the
same results are obtained as where it is regarded as a conical pendulum. The horizontal distance of the
ball from the spindle, divided by the vertical height, will give the amount of centripetal force; and
the velocity of revolution requisite to produce an equivalent centrifugal force may be found by multi-
plying the centripetal force of the ball in terms of its own weight by 70-440, and dividing the product
by twice the distance of the centre ball from the centre of the spindle in inches. The square root of the
quotient is the right number of revolutions of the spindle per minute. Considering the question in this
way, we first fix the length of the arms and the diameter of the base of the cone, or what is the same
thing, the angle at which it is desired the arms may revolve; and then, by the rule given above, we
make the speed of revolution such that the centrifugal force will koep the balls in the desired position.
Many persons find some difficulty in considering the governor as a pendulum, inasmuch as it may be
driven at any speed; but each particular speed has a vertical height of the centre of suspension above
the plane of revolution proper to itself, and one condition cannot be altered without affecting the other.
The method of considering the governor, however, as a revolving system of balls, does not involve this
difficulty, and to many engineers it will therefore be the most satisfactory.
Weight of balls-The proper weight of balls depends principally upon the nature of the mechanism
employed to transmit the agency of the governor to the throttle-valve. In practice they are generally
somewhere between 30 and 80 pounds each. It may be remarked in general, that of two governors
performing the same number of revolutions per minute, the one which is farthest removed from its
throttle-valve, and which is consequently connected with it by the most complicated mechanism, ought
to have the heaviest balls. No general rule founded upon theory can be given for determining the
proper weight of these balls in any particular case. In fnct, according to theory, the agency of the
governor is altogether independent of the weight of the balls; for the balls perform the same number
of revolutions per minute, and revolve at the same distance from the spindle, whatever is their weight.
The truth of this remark will appear clear enough if each ball be supposed to be compounded of a
number of smaller balls, each of which would certainly keep the same position as the larger ball; and
every particle may therefore be supposed to act for itself. Though the centripetal force of the balls be
increased, therefore, by adding to their weight, yet, inasmuch as their centrifugal force when in motion
is increased in the same proportion, their position, when the governor is set into revolution, cannot be
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affected thereby. An increase in the weight of the balls gives the governor more power to open or
close the throttle-valve, but does not in any other way affect its operation. Large engines, where the
valves are large and stiff, require to have the balls of the governor of corresponding size, especially if the
connections between the governor and throttle-valve are stiff and complicated; but in no other respect
is the size of the balls of importance.
The principle on which the governor acts, necessarily supposes temporary variations of the speed.
The governor, theoretically speaking, does not maintain a uniform velocity, but restores it after it has
been disturbed. Suppose that, either by reason of the diminished load upon the engine, or an increased
evaporative power in the boiler, the speed of the engine is accelerated, the governor, being immediately
affected, will cause a corresponding alteration in the throttle-valve; but in general, this alteration being
too much, the velocity of the engine will be too much retarded. This second error will again affect the
governor in the contrary way, and the speed will now be increased beyond the proper limit. Thus a
succession of alternations of effect will ensue, until the governor settles down into the position correspond-
ing to the proper speed. The agency of the governor is never brought into use before a change of ve-
locity has taken place. The very supposition that a governor acts, presupposes that a change of the
speed has ensued and which, though it corrects, it cannot prevent from arising.
Varieties of governors.-The conical pendulum is the governor employed almost universally for the
regulation of the speed of rotative steam-engines. Yet other kinds have been introduced, and in some
instances with a good effect. One very sensitive governor consists of a cylindrical double bellows,
worked by the engine, and furnished with a small cock at the orifice at which the air escapes, 80 that
it may be contracted at pleasure. When the engine runs beyond the right speed, an additional quan-
tity of air is taken in by the bellows, which, as it cannot obtain a free exit by the orifice contracted by
the cock, raises up the superior or floating part of the bellows, to which a rod is attached that closes
the throttle-valve. When the speed slackens, the floating part of the bellows subsides, and opens the
throttle-valve, until, after a few fluctuations, a mean point is reached-determined by the size of the
orifice left for the issuing air-at which the floating part of the bellows will remain nearly stationary.
A bellows on this plan has been for some years attached to the engine that gives motion to the ma-
chinery in Truman and Hanbury's brewery, and its operation is spoken of in the highest terms.
Another plan of governor was some years ago contrived by Mr. Hick, of Bolton. Upon an upright
spindle he wound a spiral feather, and then fitted upon the spindle a single ball, 80 that the ball might
be moved up or down on the spindle, but would turn on its axis in the operation. To the ball were
fixed two vanes, which, impinging upon the air when the ball was put into revolution with a high velo-
city, caused the ball to mount up on the spiral feather or thread. So long as the speed of the shaft
upon which the ball was placed remained moderate, the ball continued at the foot of the spiral; but
when the speed was increased, the impact of the vanes upon the air 80 far resisted the rotation, that the
ball rose on the spiral feather in opposition to the force of gravity; and in its ascent it closed the valve.
A governor upon this plan seems to be well adapted for steam vessels, if a spring be substituted for
the ball. The ordinary governor, however, may be rendered applicable to the marine engine if the balls
be made to move out horizontally instead of in an arc of a circle. It is clear that a common governor
would not act at sea without this modification, as the balls would diverge or collapse at every heave of
the ship. In Siemen's chronometric governor a clock movement furnished with a weight and pendulum
is employed. The clock movement carries round a bevel-wheel at a uniform speed; and another bevel-
wheel of the same size, and situated upon the same axis, is carried round by the engine in an oppo-
site direction. A bevel-pinion at the end of a crank-arm geers with both wheels in the manner of a
differential motion, and to this crank is attached a rod communicating with the throttle-valve. When
both wheels are moving at the same speed the pinion remains stationary, but if one wheel travels faster
than the other, the crank will be carried round upon its axis, and will thereby affect the throttle-valve.
There appears to be too much complication in this contrivance to enable it to gain an introduction into
practice, unless a clock movement be required for other uses than that of the engine.
The governor, as at present applied to regulate the steam-engine, acts only on the throttle-valve, to
restrain the flow of steam into the cylinder; but in our humble judgment it ought also to act upon the
injection-valve, to restrain the flow of water into the condenser. In all cases of large fluctuations of
velocity, inconvenience and danger is the inevitable effect of the injection water being left without due
regulation, and in steam vessels in particular, accidents are frequently traceable to this cause. If the
injection-cock be adjusted to give admission to the right quantity of water when the engine is working
with a mean velocity, it will clearly admit too much when the velocity is arrested 80 as to be brought
to one-half or one-fourth of the common speed; and as the air-pump cannot, when it is working 80
slow, deliver the water which rushes into the condenser in undiminished quantity, the engine becomes
choked with water, and the water sometimes runs back into the cylinder, and occasions fracture by
resisting the descent of the piston. The most common cause of breakages in steam machinery is the
entrance of water into the cylinder. Sometimes it passes over with the steam, when priming in the
boiler takes place; and at other times it finds its way from the condenser, and this will more frequently
happen if the cylinder exhausts from below than if it exhausts from the top or superior portion of the
valve casing. The right remedy for this danger is to apportion the quantity of water admitted to an
engine to the quantity of steam; and this may be accomplished by placing a throttle-valve in the
injection-pipe, which will also be operated on by the governor; but little condensing water will then be
admitted when there is but little steam to be condensed, and the engine will neither be burdened by
needless water nor starved into inefficiency by an inadequate supply.
The cataract.-The governors we have already mentioned are chiefly applicable to the rotative en-
gine. The accredited governor of the single-acting or pumping engine, is the cataract, of which instru-
ment there are many varieties. The cataract consists of a small pump plunger, and barrel, set in a
cistern of water, the barrel being furnished on the one side with a valve, opening inwards, through
which the water obtains admission to the pump chamber from the cistern; and on the other by a cock,
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through which, if the plunger be forced down, the water may be sent out again, with a rapidity propor-
tionate to the size of the orifice left by the cock. The engine, in its upward stroke, which is accom-
plished by the preponderance of weight at the pump end of the beam, raises up the plunger of the
cataract by means of a small rod, represented in the drawing of valve geering already referred to-
the water entering the pump chamber through the spindle valve, which is also represented, and filling
the pump chamber completely. By the time the engine reaches the top of the stroke, it liberates the
rod by which the plunger has been drawn up, and the plunger then descends by gravity, forcing out the
water in the barrel, and at the same time opening the injection valve. If the cock of the cataract be
shut, it is clear that the plunger cannot descend at all; and as, in that case, the injection valve cannot
be opened, the engine stands still: but if the cock be slightly opened, the plunger will descend slowly,
the injection valve will slowly open, and the engine will make a gradual stroke as it gains the water
necessary for condensation. The degree to which the cock is opened, therefore, determines the speed at
which the engine moves; 80 that by the use of the cataract, the speed of the engine may easily be ad-
justed to the quantity of water in the mine. There are other varieties of cataract employed besides
that here described, but they all depend upon the same general principle. In some cases air is used
instead of water, and in others a cylinder of oil is employed, fitted with a piston with a valve after the
manner of a pump bucket, and a small side pipe, fitted with a cock, which communicates between the
spaces on each side of the piston. When the piston of this cataract is forced down, the oil easily ascends
through the valve into the superior part of the cylinder; but when it is drawn up, the oil can only escape
by the curved pipe, from the space above the piston to the space beneath it, by passing through the con-
tracted orifice of the cock; and, though a considerable counterbalance be applied, the piston, if the cock
be partially closed, can ascend but slowly. The effect is the same as in the arrangement first described.
Expedients for ascertaining the state and power of an engine.-Water gages.-There are three kinds
of water gages: the first the ordinary gage cock, the second the glass gage, and the third the float.
The gage cock, on being turned, shows whether it is water or steam that exists at the level at which it
is inserted. There are usually three gage cocks inserted in each boiler, at different levels; and the rule
is, to 80 feed the boiler that there will be steam in the top gage-cock, and water in the other two. The
glass gage consists of a glass tube set in front of the boiler, communicating in its superior portion with
the steam space, and in its inferior portion with the water within the boiler, the position of the tube
being so adjusted that the water level stands at about the middle of its length. The tube is connected
at the top and bottom to the boiler by means of sockets furnished with cocks, 80 that the tube may be
blown through by the steam to clear it, and the water and steam may be shut off if the glass breaks.
It is unsafe to trust to the glass gages altogether as a means of ascertaining the water level, as some-
times they become choked, and the water continues to stand high in the tube though it may have sunk
low in the boiler. If the boiler be short of steam, however, and a partial vacuum be produced, the glass
gages become of essential service, as the gage cocks will not operate in such a case, for though opened
neither steam nor water will come out, but air will rush in. This sometimes occurs in practice, and
glass gages are then found to be of especial value. We may mention, however, that a vacuum in the
boiler should never be suffered to occur, as if the boiler is short of steam the throttle-valve should be
closed to a corresponding degree, or a higher degree of expansion should be employed, 80 that the due
pressure of the steam may be maintained. A better economy is to be realized by this plan of proce-
dure than by suffering the engine to draw from the boiler the attenuated steam. In steam vessels the
operation of blowing off cannot be performed, unless the pressure of the steam be considerably above
that of the atmosphere, and the neglect of this operation entails evils which are of serious moment, and
which are very expensive to cure.
The float gage consists of a float resting on the surface of the water, and communicating with an in-
dex, 80 that the fluctuations in the water level are, by reference to this index, made apparent. The
float is usually of stone or cast-iron, but is 80 balanced by a counter weight as to make its operation the
same as if it were a buoy of timber. In land boilers a float is generally employed to regulate the ad-
mission of the feed-water, and the same float may also indicate the height of the water within the boiler.
The feed-water is admitted from a small open cistern at the top of the stand-pipe, as shown in Fig. 1471.
At the bottom of the cistern is a valve, which the float opens or closes, and into the
cistern the water is poured by the feed-pump. When the valve is open the water
1471.
runs down into the boiler, but when closed it runs away by an overflow shoot. The
foot of the stand-pipe penetrates to near the bottom of the boiler, 80 that steam
cannot escape by it, but the water rises in the stand-pipe to a height proportionate
to the pressure of the steam, and a most effectual safety-valve is thus provided, which
will come into operation in the event of a dangerous pressure being attained. In the
stand-pipe a float is placed, which rises and falls as the pressure of the steam varies,
and opens or closes the damper leading from the boiler flue to the chimney. Some
stand-pipes are contracted in their diameter below the level at which the damper
float usually operates, and danger has arisen from this cause; for the float has de-
scended into this narrow neck when there was no longer a pressure of steam in the
boiler, and by stopping up the passage it has prevented the access of the feed-water.
The length of the damper chain should be 80 regulated as to obviate accidents of this
description, which are not unlikely to burst the boiler, by causing the boiler bottom
or flues to become red-hot.
Salt gages.-In steam vessels it is a commendable practice to apply salt gages to
the boiler, 80 that the water may never be suffered to reach an injurious degree of
saturation. These gages usually consist of glass balls, which operate on the principle
of the hydrometer, rising to the surface when the water becomes highly concentrated,
and therefore heavier. In some instances bulbs of this description, enclosed in a large glass tube, are
fitted to the front of each boiler; but the general plan is to draw off some of the water into a separate
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vessel, and then to test its saltness by an instrument provided for the purpose. The Don Juan steamer
was fitted with large copper balls, to determine the saltness of the water in the boiler: they were of
course totally immersed in the water, and as the water increased in density they rose and opened the
blow-off valve, which was made of such a construction as to be capable of being easily opened. There
is too much refinement probably in this expedient, and the ball requires to be large to realize a sufficient
motive force to make the action of the instrument certain, yet the operation of the plan is very complete,
especially if conjoined with a self-acting feed, as was the case in the instance referred to. A good salt
gage is still a desideratum, for the plan of drawing off water from the boiler, and testing it by an hydro-
meter, is very inconvenient in practice. A salt gage, to be a convenient instrument, should indicate, by
a hand or other simple appendage, the density at the time of observation of the water in the boiler, and
such an instrument becomes of especial importance if the amount of water blown off be regulated by the
position of the feed-cocks, as is done in the case of Mr. Lamb's blow-off apparatus for steam vessels,
which is now gaining an extensive introduction. In this apparatus the mouth of the blow-off pipe within
the boiler is situated near the water level, whereby it catches and removes from the boiler the particles
of impalpable matter which, by their subsidence on the flues, occasion scale.
Mr. Lamb attaches a valve to the mouth of the blow-off pipe regulated by a float, with the view of
preventing the steam from blowing off when the water has subsided below the said mouth, which is
situated about 12 inches beneath the average water line. The float is made of copper, of the form of
an oblate spheroid, with a tube passing through it for the reception of a spindle, the position of which in
reference to the float is regulated by nuts above and below the float, which connect with screw threads
cut upon the spindle. The valve resembles a flute key. The lower end of the spindle is attached to
the valve arin, 80 as to enable the float to exert a greater power, and the upper end of the spindle moves
in a guide attached to any convenient part of the boiler. By this apparatus the operation of blowing
off is continuously performed; but when the salt gage shows that the quantity of water blown off is
either needlessly great or insufficient, the position of the feed-cock is altered 80 as to give a diminished
or increased supply. When more feed-water is admitted, the float upon the surface of the water opens
the blow-off valve more widely, and permits a larger quantity of water to be blown out; and when less
feed-water is admitted, the contrary effect is produced. The operation of the float, therefore, is to main-
tain the water at a uniform level, and also to preserve the water within the boiler at a uniform density
80 soon as the right position of the feed-cock is ascertained. In boilers which are thus worked, or to
which brine pumps, or any continuous blow-off contrivances are applied, an efficient salt gage is indis-
pensable, as there can otherwise be no intimation of the accidental interruption of the operation, and
much mischief may be the result. In the ordinary way of blowing off, where the engineer keeps the
blow-off cocks open until the water level has descended any given number of inches, it is certain that,
if the water level descends, a certain volume of super-salted water has been ejected; unless, indeed, as
has sometimes happened where there is a difference of pressure in the different boilers, one boiler has
discharged its contents into the other when all the blow-off cocks are opened at once. But in the ordi-
nary operation of blowing off one boiler at a time, a determinable quantity of water is expelled by blow-
ing out at determinate intervals with a certainty which leaves nothing to the chances of accidental de-
rangement, and which the use of the salt gage in the case of boilers fitted with any description of con-
tinuous blow-off is indispensable to insure.
Steam gage.-The steam gage consists generally of a simple tube, sometimes of glass and sometimes
of iron, bent 60 as to form the letter U. One of the ends is placed in communication with the boiler, and
the other end is open to the atmosphere. Into the bent part of the tube mercury is poured, which, it
not acted on by the steam, will stand at equal heights in both legs of the tube. If, however, the steam
be admitted to act upon the mercury at one of the extremities of the tube, it will force it up in the
other leg, and may be made to indicate the amount of pressure on a divided scale. The scale is com-
monly divided into inches and parts of an inch, each inch corresponding to a pressure of very nearly
one pound on the square inch. Some people prefer estimating the elasticity of the steam by pounds
per circular inch. For this purpose each of the divisions of the scale ought to be 1,³ₓ inches, and these
divided again into 10 equal parts, when the pressure in lbs. and tenths of a lb. will be shown by the
scale. When the tube is constructed of iron, it is necessary that a float of wood resting on the top of
the mercury should ascend above the tube, and indicate on a proper scale the place of the mercury. It
is clear that every inch the mercury rises in the open end of the tube occasions a difference of level of
two inches, for the level in the leg pressed on by the steam falls an inch at the same time that the level
in the open end rises an inch. Some steam gages consist of a straight glass tube, with one end termi-
nating in a small cistern of mercury, while the other end is open, and the mercury is forced up into the
tube by the pressure of the steam. In this case the graduation has to be such that a pound pressure
will be represented by two inches in height upon the scale, for the level of mercury in the cistern does
not subside appreciably by the rise of mercury in the tube. The siphon gage is the one generally
employed, and it appears to be entitled to the preference it enjoys. Every boiler ought to be provided
with a steam gage as a precaution of safety, as well as a means of seeing that the steam is kept steadily
up. If the pressure rises to any dangerous pitch, the mercury will be blown out of the gage, and the
escape of steam will notify the existence of danger. In such case, if the safety-valve cannot be raised,
from derangement or otherwise, the best plan is to open the blow-through valve of the engine. To
start the engine might cause a flow of water from the feed-pump over hot plates within the boiler, if the
water be at the same time low within it, and an explosion might be the consequence of such an indiscretion.
Vacuum gage.-The vacuum gage is a barometer for determining the relative elasticities of the air
and of the attenuated vapor in the condenser. It consists of a glass tube, of which the inferior orifice
is inserted in a small cistern of mercury, while the superior orifice is fitted with a small pipe, which
communicates with the interior of the condenser. The air presses on the surface of the mercury in the
cistern, while the pressure of the condenser vapor only exists within the tube, and the mercury rises in
the tube to a height corresponding to the difference of these pressures-usually to a height of about 27
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inches. There is a good deal of oscillation in the mercury of a vacuum gage if the cock in the pipe
leading from the top of the tube to the condenser be opened fully, and it should therefore be nearly
closed before the observation of the quality of the vacuum is made, else it will be very difficult to tell
at what point the mercury stands on the average, in consequence of its rapid rising and subsidence. In
the graduation of vacuum gages reference enough is not generally had to the size of the mercury cis-
tern, which is usually made small; and as the subsidence of the level of the mercury in the cistern falls
considerably when the tube becomes full, the graduation, if made in inches, is correspondingly inaccu-
rate, as the divisions should be less than an inch apart to represent inches, if the surface of the inercury
in the cistern falls. Some vacuum gages are made on the principle of indicating the difference between
the vacuum in the condenser and a perfect vacuum, instead of the difference between the vacuum in the
condenser and the pressure of the atmosphere. This species of vacuum gage is much used in sugar re-
fining, and is convenient there from its portable nature; but it has not met with any extended adoption
for the uses of the steam-engine. A siphon vacuum gage, like the steam gage in form, is also some-
times used; but the straight glass tube, arranged in the manner we have described, is generally pre-
ferred to any other arrangement.
The indicator.-The indicator is an instrument for determining the amount of power actually exerted
by an engine. In computing the power of engines, one important element is the unbalanced pressure
of the steam on the piston; and any inaccuracy in the statement of this particular must vitiate the cal-
culation, and give an erroneous result. In all ordinary cases, even when no expansion geer is used, it is
wrong to reckon the pressure of the steam in the cylinder as uniform, or the condensed vapor as of a
constant elasticity; and to assume that the pressure in the cylinder is the same as that indicated by
the steam gage, is to introduce a fallacy into the computation of power. The use of the indicator is to
measure and register the variations of pressure during a complete stroke of the engine, and thus to ob-
tain accurate data whereby the effective power of the engine may be computed.
The indicator consists of a small cylinder c, Fig. 1472, placed in connection with the cylinder of the
engine either above or below the piston, and fitted with a piston P, which is connected with the spiral
spring 8. By opening the cock of the indicator the steam is admitted below the piston P, on which it
presses during the whole stroke. If the pressure were uniform, the piston would remain stationary
but if the pressure vary, the piston will have corresponding movements either up or down. If a pencil
p, be attached to the piston-rod, it will register the variations of pressure upon a piece of paper held
against it; but, unless some provision were made to give a clear space upon the paper at each instant
of time, one mark of the pencil would be upon the other, and the registration could not be deciphered
but, if the paper receives a continuous lateral motion in one direction during the down stroke of the
1472.
piston, and a reversed motion during the return stroke, while the pencil moves vertically, a continuous
line will be traced upon the paper, which will inclose a space, and the vertical ordinates of the figure
will represent the effective pressure during a complete stroke. Instead. however, of using a plain sur-
face, as was done in Boulton and Watt's establishment for some time after its formation, it is now the
universal practice to wind the paper round a cylinder, or roller, which is made to turn upon its axis
with a reciprocating motion, and the apparatus is thus rendered more compact. If the pressure of the
steam were uniform, the line described upon the paper would be in a plane perpendicular to the axis of
the roller, so that, if the paper were unrolled, the line would be straight. The paper is fastened to the
roller by means of a catch h, the edge of which is graduated. Before the instrument is connected with
the steam cylinder, the roller is set in motion, and the pencil then describes a neutral line, which repre-
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sents the pressure of the atmosphere-any vertical ordinate above this being the steam pressure above
that point, and any vertical ordinate below, the pressure below it. If the connection between the indi-
cator and the cylinder be now formed, while steam is entering the cylinder, the piston of the indicator
will rise; and, if steam is escaping from the cylinder, it will fall; the extent of rise and fall being reg-
ulated by the spiral spring, which yields more as the pressure becomes greater. The vertical motion
of the pencil, combined with the circular motion of the roller, will form a curve more or less regular,
the vertical ordinates of which represent the values of the steam pressure and vacuum during a com-
plete stroke, measured by the scale which is marked upon the roller clasp. The graduation of this
scale depends upon the strength of the spring s, which forces the piston down when the steam ceases to
force it up; because, the stronger the spring is made, the smaller is the distance through which steam
of a given force will compress it by raising the piston. The alternate motion of the roller is given by
connecting it with any reciprocating part of the engine, such as the parallel motion, by means of a cord
attached to the pulley a, which is fixed upon the same axis as the paper roller d. This cord gives mo-
tion in one direction, and the return motion is received from a spring m, which is coiled up like a watch-
spring; l is a guide pulley for changing the direction of the cord when it passes from the pulley a; it
is not shown in its place except in the bottom plan, where part of it is dotted in.
Let us now suppose the engine to be in motion, and the stop-cock of the indicator closed. If the
cord be drawn out by hand, or connected with the engine, the pencil pressing against the paper will
describe the horizontal line representing the atmospheric pressure; and if, when the piston is at the top
of its stroke, the indicator stop-cock be opened, it will commence its registration. When the steam be-
gins to rush into the cylinder, it will, of course, also press upon the piston of the indicator, which it will
raise, and with it the pencil; and the roller, with the paper upon it, being moved by its connection
with the engine, a line will be traced upon the paper, which rises higher up on the cylinder as the pres-
sure of the steam increases, and comes lower upon it as the steam pressure subsides. The area of the
curve traced out by the pencil, therefore, represents the pressure on the piston through all its variations,
and, when multiplied by the number of strokes, represents the power exerted by the engine. This
power has no connection with the nominal horse power, which is determined by the dimensions of the
engine, and which does not vary with variations in the pressure of the steam; but it is the effective
power, or the power actually exerted.
The indicator, however, not merely tells the amount of power exerted by every stroke of an engine,
but the nature of the faults by which the power is impaired. A particular form of the indicator dia-
gram shows that the ports of the cylinder are too small; and the indication in such a case obviously is
to enlarge them. If the valve be wrongly set, the indicator will explain the nature of the imperfection,
and its adjustment then becomes easy. By the indicator too the amount of power consumed by each
of the several mechanisms of a factory may be determined, and the relative values of different oils fixed
that may be employed for the lubrication of the shafts. If, for example, it is wanted to know the
amount of power consumed by a fan or a saw-mill that may be driven by the engine, the machine in
question has only to be put in connection with the engine, while all the rest of the machinery of the
factory is cast off; and if the indicator be applied to the engine, the amount of power consumed in dri-
ving the one machine will be determined; and then it will be found, by taking another diagram, with
all the machinery on, what proportion this part bears to the total power. In testing the quality of oils,
if it be found that the engine requires more power to drive the shafting with one kind of oil than with
another, that which involves the largest expenditure of power is, of course, the worse. To read off the
indications of the indicator is a thing every one may do after the foregoing explanation. The pencil
describes a curved line inclosing a space. Across that space any number of lines may be drawn at
right angles to the atmospheric line. The lengths of the lines are then measured on a scale, and their
mean taken, which mean represents the power exerted. The indicator is an invention of Watt's, but
it does not very clearly appear who it was that first applied the pencil to trace a curve. The applica-
tion was, however, first made at Soho, probably by Mr. Southern or Mr. Creighton.
Continuous indicator.-A continuous indicator is an instrument that will not merely ascertain, but
also register the work done by an engine during any given period, whereby the performance of one
engine may be compared with the performance of another, to the end of ascertaining which is the most
economical in fuel. In Cornwall this object is accomplished by means of a counter, which merely reg-
isters the number of strokes made by the engine; but this expedient will only answer where the load
upon the engine is constant and easily measurable, and becomes of but little avail in a steam vessel,
where the load is continually varying. The invention of an instrument of a simple kind, that will re-
cord the varying power of the engine under all circumstances of speed and variation of expansion, be-
comes an object of no trivial importance, when it is recollected that such an instrument is indispensable
to the success of any effectual scheme of registration. This chasm has now been filled up by W. H.
Linslay. By registration we mean the determination by an authorized person of the power exerted by
steam vessels, or, in other words, the work done in relation to the fuel consumed, and the publication of
these results obtained from a large number of steam vessels at regular intervals; 80 that it may appear
on the face of a table suitably drawn up what steam vessels are the most effectual. These published
tables would, therefore, be identical in all their main features with the tables published in Cornwall by
the Messrs. Lean; and indeed the measure we propose consists in the extension to steam vessels of the
system of registering the duty of engines pursued in Cornwall, and which has produced such beneficial
effects in that district.
The best proof of the saving in fuel derivable from the plan of registering the duty of steam-engines
consists in an enumeration of the wonders it has already done; and we find that the amount of work
performed in Cornwall by a bushel of coal, represented by 20,000,000 in 1815, had arisen to 60,000,000
in 1843. Nor is this a solitary case, but, on the contrary, it is the average duty of all the engines regis-
tered at the two periods, 80 that the expense of fuel to do the same amount of work is at present only
one-third of what it was in 1815, and we think we may add only one-third of what it would have been
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now, had the plan of registration not been adopted. The Messrs. Lean have drawn up a table which
makes the value of this system very conspicuous, and from which it appears that the Cornish mine
owners are now saving about £85,000 per annum in their limited operations, by the simple expedient
of registering and publishing the duty of their engines. Such a practice puts all the engineers upon
their mettle, and induces an emulation out of which improvement cannot but spring; and at the same
time it stimulates all engine attendants to a more sedulous attention, as any negligence on their part
will be sure to tell to their disadvantage. If such a saving can be realized out of the contracted sphere
of Cornish engineering, what a magnificent result might not be realized by the application of the plan
to the innumerable steam vessels of this country ! Yet the saving in the cost of the coal in the case of
steam navigation, important as it would be, is not the greatest benefit of such an economy the powers
of steam navigation would be prodigiously increased, and its profits correspondingly augmented, by any
improvement by which the quantity of coal carried was materially lessened for steam vessels could
then go farther without a relay of coal, or could carry more cargo, and the growth of our steam marine
would just be in proportion to the extension of the limits which now hinder its development.
It is needless, however, to dwell much on the advantages of the system of registration, as they must
be conspicuous enough to every one who gives attention to the subject. Professor Moseley professes to
have invented an indicator of the continuous kind, but it is far too complicated for ordinary practice;
and as some of the parts drive the other parts by friction surfaces, which are apt to slip should a little
oil chance to fall upon them, its indications are correspondingly uncertain. A suitable indicator being
obtained, every steamer of any pretensions should be provided with one, and an inspector should then
be appointed, in whose skill and honesty all parties have confidence, and whose business it should be
to examine the indications of the several instruments, and make up from thence tables of the perform-
ance of each vessel, which should periodically be published. The quantity of coal consumed could of
course only be got at by a reference to the coal accounts of the several vessels; and it would be a good
thing if those coal accounts were all kept upon a uniform plan to facilitate the discovery of this ele-
ment.
A continuous indicator of a very complete description was some years ago brought under the notice
of the British Association by Dr. Lardner, though its expense and complication were too great to war-
rant its introduction in practice. A web of paper was wound upon a small brass drum, and a larger
drum, which was put into revolution by means of clock-work, wound the web of paper off the small
drum on to itself. At suitable distances round the larger drum pencils of different colors were placed,
which were acted upon by floats placed in siphon tubes of mercury, to which the steam-pipe, condenser,
dec., were respectively connected. When the pressure of steam in the boiler varied, the pencil attached
to the float in the siphon gage communicating with the boiler was elevated or depressed correspondingly,
and traced a line upon the drum above or below the right position. At the termination of the voyage
the paper was taken off and translated into words, and the difference in the colors of the different pen-
cils prevented the lines made by each from being confounded with any other. There was more trouble
connected with the use of this instrument than engineers would willingly take, and more expense than
the proprietors of steam vessels would willingly incur, added to which it took no satisfactory cognizance
of any variation in the degrees of expansion, though that is the most important of the elements demand-
ing registration.
Counter.-The counter is an instrument with wheelwork 80 contrived, that, by every stroke of the
engine, an index hand is moved a certain distance forward, so that it registers or counts the number of
strokes made by the engine during any given period. The construction of the counter varies very much:
in most cases, however, the wheels are moved round by a pendulum attached to some vibrating part of
the engine, the wheel being carried on one tooth by every vibration. Some of the French counters are
extremely neat and portable, being much like a pedometer watch in size and appearance. A very ele-
gant counter for locomotive engines has been contrived by Mr. Adie: an endless screw works into the
rim of two small wheels, situated on the same axis, but one wheel having a tooth more than the other.
A differential motion is thus obtained, of great slowness, for the wheel with the additional tooth will
only move slightly more slowly than the other wheel, and the result is indicated by the difference of
the two speeds. The end of the screw is attached to a revolving part of the engine, by means of an
appropriate fastening, and the wheels hang down like a pendulum from it, and do not turn with the
revolving part in question, 80 that the wheels are turned on their axis by the screw, without any thing
of the nature of reciprocation. The counter was first introduced by Mr. Watt, and was attached by
him to the Cornish engines for the purpose of showing the proportion of savings in fuel due to him from
the application of his improved engine; and in the case of those engines which were uniformly loaded,
the counter afforded a correct indication of the power exerted. The number of strokes of the engine
multiplied by the capacity of the pump, and the height through which the water is raised, will give a
quantity representative of the engine power; and in the case of pumping engines, the indications of the
counter will enable us to determine the duty, the registration of which has in Cornwall been productive
of such beneficial effects.
Dynamometer.-In screw vessels the forward thrust of the screw has been measured by a dynamo-
meter, an instrument constructed on the principle of a weighing-machine, in which a small weight or
spring pressure at the index will sustain a much greater weight or pressure at the other end. In the
Rattler screw steamer the forward thrust of the screw, as determined by the dynamometer, was found
to be about four tons, and it was also found that when a piece of paper was drawn slowly along be-
neath the index, a pencil attached to the index described upon the paper a serrated line showing great
fluctuations of pressure in the different positions of the screw. The greatest thrust is when the screw
blade is in a line with the stern post. A dynamometer has also been employed in Woolwich dockyard
to test the tractive force of paddle-wheel steamers. Morin's dynamometer is usually employed for as-
certaining the resistance of railway trains. It consists substantially of two blades of steel, the flexure
of which indicates the resistance.
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ENGINE, VARIETIES OF THE STEAM.
ENGINE, VARIETIES OF THE STEAM-Condensing and high-pressure enginea-Steam-engines
of every kind are divisible into two great classes-high-pressure engines and condensing engines. Con
densing engines are sometimes also worked with a high pressure of steam, and the distinctive appellation
of high-pressure engines is applied to engines of which the steam is not condensed. All locomotive
engines are of the high-pressure variety; and generally all engines are made on the high-pressure plan,
where the carriage of condensing water would be inconvenient, or the first cost of the machine becomes
a point of more importance than an increased consumption of fuel High-pressure engines are neces-
sarily more expensive in fuel than low-pressure engines, as they occasion the loss of the power derivable
from a vacuum; and as the quantity of heat in the same weight of steam is nearly the same at all
pressures, there is no countervailing source of economy to compensate for this deduction. Where high-
pressure steam is employed, it is expedient to make the pressure considerable. as the deduction to be
made for the pressure of the atmosphere is less in proportion, with a high, than with a moderate
pressure. Some locomotive engines are worked as high as 90 pounds on the square inch.
The pumping engine.-The pumping engine, as arranged by Watt at an early period of his career, and
the modern pumping engine, differ from this primitive type only in a few details of secondary impor-
tance; excepting, however, the use of steam of a higher pressure, and the larger employment of the
principle of expansion, by which a greatly increased economy of fuel has been realized.
All the Cornish engines are furnished with a steam-jacket to the cylinder, and, in some cases, a flue
winds spirally round the jacket, carrying hot air from a small fire in the engine-house, to maintain the
temperature of the steam unimpaired. Where this is not done, the cylinder is encased in a large jacket,
filled with some non-conducting substance, or is covered with wood.
In most pumping engines one end of the beam is made longer than the other, the intention being to
enable the cylinder to have a long stroke, without communicating such a velocity to the pump buckets
as will make them strike hard, and wear themselves quickly out. One advantage of a long stroke is,
that high-pressure steam may be used without being obliged to make the parts inconveniently strong
for the principal parts of the engine have to be made of the same strength whatever be the length of
the stroke, and to increase the diameter of the cylinder, to compensate for shortness of the stroke,
involves the necessity of a strong and expensive engine. Woolf's plan of employing two cylinders is
sometimes used as an alternative remedy, and in some recent engines the plan has been much simpli-
fied, by placing the small cylinder on the top of the large one, and working both with the same
piston-rod; although there is less irregularity in the impelling force, there is greater complexity in the
machine, 80 that a long stroke with an unequal beam appears to be a preferable expedient.
The pump valves of engines working high lifts are a continual source of trouble and expense, and
many expedients have been contrived to abate the shock and tremor caused by their rapid closing. Of
these, the best is probably the valve known as Harvey and West's, which is, in all its material features,
identical with the balance valve. This valve presses down with very little force, and an annular recess
is frequently made in the pump bucket, which is filled with end-wood, on which the valve falls. In
some engines canvas valves are used even for the air-pump of engines which are intended to work at a
high speed-in some cases with good effect; though in others, probably from the employment of an
inferior quality of canvas, the valves have worn out very quickly. The bucket consists of a metal disk,
perforated with a large number of small holes, and these holes are all closed by a canvas disk, which
rises and falls like a common pot-lid valve; with the exception that it is bound down at the eye, and
the edges only left. India-rubber has been tried as well as canvas, but it sinks too much into the holes,
and has not answered 80 well.
If there be any case in which the use of an engine beam can be excused, it is in the case of a pumping
engine; direct action is so inconvenient and precarious over the mouth of a mine. The main beam rests
on a wall of masonry near the mouth of the mine, as may be seen by a reference to the plate of a
" Cornish pumping engine." At the one end of the beam is the cylinder, and at the other end the pump-
rod, which penetrates into the mine. From the pump-rod end of the beam the rods for working the air-
pump and feed-pump are suspended. The air-pump is shown in dotted lines, and beyond it appears
the condenser, situated in the cold-water cistern, with a valve attached to the end of a curved pipe, for
admitting the injection water-the valve being wrought by the cataract which stands beneath the valve
geering. A rod passes through the end wall of the house, for adjusting the position of the centre of the
radius-bar of the parallel motion. The cylinder end of the beam is armed with catch-pins, which strike
on the spring beams stretching from the lever wall to the end of the house, if the piston proceeds down
80 far as to endanger the cylinder bottom. The feed-pump stands on the top of the eduction pipe: the
valve geering we have already explained. It is usual in the Cornish practice to make the lowest pump
of the series of lifts a lifting pump, and all the others forcing pumps. The plungers of the forcing
pumps are more easily packed than the buckets of the lifting pumps, and there is not the same risk of
drawing air; but the lowest pump is made a lifting one, to facilitate extensions to a lower level, and also
to prevent the pump valves from becoming inaccessible if the water accumulates in the mine.
Rotative engine.-We shall not here dwell upon any description of the ordinary rotative or mill-
engine, as we look upon it now as a mere piece of antiquity.
Marine engine.-The marine engine has now become the most important variety of the steam-engine,
not merely on account of the great extension of steam navigation, but because it is fast superseding the
ordinary steam-engine, even for land purposes. We shall therefore enter into the consideration of the
structure and operation of this engine with considerable fulness of detail, and much of what we say will
also be found to illustrate the merits of the other varieties of engine.
Paddle-wheels.-If a body moves through a quiescent fluid with a given velocity, or if a fluid moving
with a given velocity impinge against a body at rest, the resistance will in either case be as the square
of the velocity, while the power requisite to overcome that resistance will be as the cube of the velocity;
80 that if the velocity of a steamer be doubled, the resistance experienced in passing through the water
becomes four times greater than before, and the power required to achieve that doubled speed eight
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times greater than before. This is explained by the circumstance that the resistance of a body moving
in a fluid is proportionate to the number of particles struck and the velocity with which they are struck
as twice the number of particles are struck, and each particle with twice the force, there is four times
the resistance; and as the strain occasioned by this resistance is four times greater upon the engine, and
the engine has at the same time to work at twice the speed, there must be four times the expenditure
of power.
The absolute resistance which a quiescent fluid opposes to a plane surface moving through it with a
given velocity, is equal to the weight of a column of the fluid whose base is the plane, and altitude the
same as that which is due to the velocity of motion; that is, the height through which a heavy body
must fall to acquire that velocity by the action of gravity. Reduced to a simple Rule,
Resistance area X velocity squared X 0.9715.
When a fluid impinges upon a plane surface in an oblique direction, it will impel the plane in a
direction at right angles to its surface with a force which is proportional to the square of the velocity of
motion, the density of the fluid, the area of the plane, and the square of the sine of the angle of inci-
dence. The equation for the resistance then becomes-
Resistance = area X velocity squared X sine squared of angle of incidence X 0.9715.
When a paddle-wheel is first put in motion, every point upon it describes a circle round the centre;
but as the vessel begins to move, the forward motion of the vessel being compounded with the rotative
motion of the wheel, each point describes in the air or water a curtate cycloid differing from a circle in
the proportion of its propinquity to the centre. The speed of the vessel is usually about a third less
than the speed of the extremities of the paddle-arms, and a circle, therefore, described on the wheel with
a radius of two-thirds the length of the paddle-arm, will travel with the same speed as the vessel passes
through the water. This circle, which is usually called the rolling circle, is such, that if the vessel were
travelling upon land upon wheels of that size, and with the same speed of engine, her velocity would
remain unaffected.
As every point in the radius of the wheel moves with a greater velocity as it is further from the centre,
it is clear that the portion of the paddle-board furthest removed from the centre must experience a different
degree of resistance from the portion nearer to it; and the mean centre of pressure therefore cannot be
at the centre of the float, but at a point nearer the outer edge, and varies also with the angle of the
paddle and the depth of the immersion. For light immersions it may be reckoned that the resistance on
any point of the paddle-board varies as the 3d power of its distance from the rolling circle; and
assuming this, we arrive at the following rule: From the radius of the wheel subtract the radius of the
rolling circle; to the remainder add the depth of the paddle-board, and divide the fourth power of the
sum by four times the depth; then from the cube root of the quotient subtract the difference between
the radii of the wheel and circle of rotation, and the remainder will be the distance of the centre of
pressure from the upper edge of the paddle. Instead of the common radial paddle-wheel, a description
of wheels with moveable floats, known as Morgan's wheels, are now much employed, though they were
for many years regarded with disfavor. In this wheel each paddle. which is of iron, is hung upon a
centre in the manner of a throttle-valve, and is connected by a rod to a fixed eccentric, either on the
side of the ship, or upon the spring beams which sustain the end of the paddle-shaft. When the wheel
revolves, the operation of the eccentric maintains every float in the vertical position, or nearly so, whereby
a more perfect action of the wheel is realized than if the floats were fixed, as in the case of the common
radial paddle with wooden floats.
In considering attentively the action of the paddle-wheel, it will be remarked, that although the cir-
cular velocity of the wheel is uniform, very unequal portions of the cycloidal path are described in equal
times; for the space described during the first quadrant is more than double that described during the
second, and that described during the third quadrant is less than half that described during the fourth.
The result of this action is, that the verticle paddle-board, instead of being the most effectual in the propul-
sion of the vessel, as might appear on a cursory survey, is the least effectual of the floats immerged for
the horizontal velocity of a float, when in the vertical position, is at its minimum point, and consequently
in the common radial paddle-wheel both the entering and emerging floats are the more effectual. In
the feathering paddle this action is materially modified, and the feathering paddles do not involve the
same loss of power. By rendering a smaller diameter of wheel applicable, too, they enable the engines
to move at a higher speed, whereby their efficacy is increased a vessel that will go 13 miles an hour
with the common wheels, will make a mile an hour more with the feathering wheels, the power of the
engines being the same in both cases.
The screw propeller.-There is too little yet known respecting the performance and manner of opera-
tion of the screw propeller to justify the formation of rules pretending to regulate the details of practice;
but the conviction of the most experienced engineers appears, at the present time, to be, that while for
river steamers the feathering paddle is the best propeller, the screw has, at least, established a claim to
equality in the case of ocean steamers; while as a propeller for vessels fitted with auxiliary power it
has an undisputed superiority. For vessels of war the screw has the manifest recommendation, that it
is less exposed to shot, and the whole of the machinery for driving the screw may be placed under the
water-line, which is not possible in the case of paddle-wheel steamers.
The form in which the screw propeller was first applied to the Archimedes steamer consisted of a broad
helical feather attached to a cylindrical axis, driven by the engine, and which, working in the water in
nearly the same manner as a carpenter's screw works in a piece of wood, carried the vessel forward in
the direction of its length. The helical feather made & single convolution round the axis, the length of
the convolution being regulated by the pitch of the screw but this arrangement was relinquished, as it
gave a vibratory motion to the boat, interfered with the action of the rudder, and threw the strain too
much on one side of the axis; and two half convolutions of a double-threaded screw were adopted,
instead of the whole convolution of a single-threaded screw. In later applications the screw has been
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made much shorter than what answers to half a convolution; about one-sixth of a convolution is now a
common proportion. In the Great Northern, the area of midship section at 16 feet draft of water is 540
square feet, while the screw contains about 90 square feet, deducting the area of the boss. The speed
of the vessel is nine statute miles an hour, and the slip of the screw is one-tenth.
If, when the vessel is at rest, the engine causes the screw to revolve on its axis without advancing
forward in the water, every point of its surface will describe a circle, the magnitude of which is propor-
tional to the distance of the describing point from the centre of motion. It is clear the surface of the
screw will strike the water with a force that is due to the velocity of motion, and the water will be
impelled in a direction at right angles to the surface, with a velocity corresponding to that of the
revolving feather, but varying in proportion to the distance of any particular point from the axis. This
is the force that is effective in propelling the vessel, and it will be seen that it is greater, at a greater
distance from the centre, decreasing gradually as we approach the axis where the velocity of the
revolving surface is small. On the other hand, if the vessel moves forward in the direction of its length
while the screw is prevented from revolving on its axis, every point on the surface of the projecting
feather will trace a straight line, equal in length to the distance passed over by the vessel or, in other
words, the screw, in being pulled forward, will displace a cylinder of water of its own diameter and of
the length of the vessel's motion, occasioning, of course, a waste of power in the operation. When the
screw is put into action by the engine, both of these resistances are encountered. If the action of the
propeller were perfect, the screw would operate as if working in a nut; and as there would be then no
loss by slip, we could ascertain the speed of the vessel by multiplying the number of revolutions by the
pitch of the screw, and dividing by 88, which would give the speed per hour in statute miles; but in
practice the speed is generally from one-tenth to one-twentieth less than the speed thus ascertained.
There is not an invariable loss by slip, however, or at least not an apparent loss, for in some cases, the
vessel is propelled at a faster rate than if the screw worked in a solid. One cause of this anomaly
probably is, that the water, in closing in upon the wake of the vessel, having a motion given to it, the
screw impinges, not upon still, but upon moving water, whereby an increased reaction is obtained; but
something depends too upon the size of the screw, and in general it has been found that when the
superficial area of the screw, taken as a disk, is about one-fourth of the area of the immersed section of
the vessel, the speed will be as great or greater than if the screw was working in a solid. The water
partakes very little of the rotatory motion of the screw, but is drawn in on all sides from the circum-
ference towards the centre, and is then projected aft in a column slightly conical, as it recedes from the
screw. The pitch of the screw, or the angle at which the blades are set, differs necessarily with the
form of the vessel and the power of the engine; or, in other words, with the speed expected to be at-
tained a common enough angle is from 66 to 68 degrees with the axis.
In settling the dimensions and pitch of screw proper for any particular vessel, the first indication is
to make the diameter of the screw as large as it can be got; and then the probable speed of the vessel,
judging from the power and form, is to be estimated, which, after fixing the number of revolutions and
making an allowance of say one-tenth or one-twelfth for slip, will give the pitch of the screw. Most of
the screws now used are made with two threads, or have two blades. Screws with three blades act
more equably, as the whole of the blades are never in the line of the stern-post at once, at which point
the forward thrust is greatest; but double-threaded screws seem upon the whole to be the most
effective, and they may, if necessary, project beneath the keel, as they can be turned into the horizontal
direction when the vessel is in harbor, to prevent them from touching the ground. To ascertain the
amount of helical surface of a screw making one convolution, multiply the sum of the radii of the screw
and of the central boss by their difference, and the product will be the difference of their squares: mul-
tiply this number by 31416, and the product by the secant of the angle of the screw, and the result will
be the area of the helical surface sought.
Bourne's double-power engine.-The screw propeller has created a new exigency in steam me-
chanism. The propeller generally requires to make a greater number of revolutions than the engines
can conveniently perform; and cog-wheels have in many cases been introduced to bring up the speed,
thus introducing into steam vessels the jar, tremor, and liability to fracture incidental to the use of such
devices. To remove this source of objection it is necessary that the engines should be coupled direct to
the propeller shaft; but as the valves of the air-pumps would strike 80 hard as to knock themselves to
pieces if the engines were worked at any very high speed, and as the various contrivances of canvas and
India-rubber valves are of doubtful efficacy in such an emergency, Mr. Bourne has contrived a species
of engine in which the whole of the air-pump valves are replaced by a particular arrangement of slide-
valve, whereby the engine may be worked at any degree of speed without inconvenience. One effect of
this innovation is to make engines work more noiselessly than before, as there is no longer any shock,
such as that which attaches to the action of the foot and delivery valves and the valves of the air-pump
bucket in common engines. But the most important feature of the arrangement is, that by enabling the
engines to work at twice the ordinary speed, it enables them to exert twice the ordinary power. It is
not for screw vessels alone, therefore, that such engines are appropriate, but they may be applied with
advantage to most of the purposes for which steam power is required. In the case of mill engines they
possess the recommendation of imparting a more equable motion to the machinery, and in other cases
they may be 80 arranged as to save fuel by permitting a larger expansion than could be allowed with a
lower speed.
The boiler of the double-power engine is for the most part constructed with upright tubes, and the
engine set upon the boiler in all powers under 40 horses. The following are the chief dimensions of a
one-horse power engine and boiler :-Diameter of boiler, 16 inches; height of boiler, 40 inches; diameter
of furnace at crown-plate, 12 inches; diameter of furnace at bars, 13 inches; height of crown-plate
above bars, 12 inches; depth of fire-bars, 2 inches; depth of ash-pit, 4 inches; depth of smoke-box, 4
inches; diameter of chimney, 3 inches. There are 36 tubes in the boiler, 1 inch in diameter, and 16
inches long. but 12 inches in the length of tube only passes through the water, and is alone counted as
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effective: the thickness of the shell of the boiler is three-sixteenths; and the pressure the boiler is cal-
culated to bear is 80 pounds, though 70 pounds is the working pressure. The diameter of the cylinder
is 2 inches; length of stroke, 3 inches; number of revolutions per minute, 872; number of feet travelled
by the piston per minute, 436; and though these dimensions are small, that they will give fully a horse
power is made manifest by a simple calculation. The area of a cylinder 2 inches in diameter is 3.1416;
and if the effective pressure be taken at 60 pounds per square inch, instead of 70 pounds, (as a com-
pensation for friction and loss of effect from radiation and expansion,) we have a force of 1881 pounds
urging the piston at a speed of 436 feet per minute, which is equivalent to 82,184 pounds raised one foot
high in the minute; and dividing by 33,000, this gives us about 21 horse power. On calculating the
amount of tube surface, it will be found to amount to 12 square feet, and the furnace surface will
amount to about sh square feet more, making a total of 151 square feet of heating surface per horse
power, which is a large allowance. The weight of the boiler is about 24 cwt., and the total weight of
engine and boiler, with water in the boiler, is about 41 cwt.
Of the 40-horse power engine and boiler on the double-power plan, the following are the principal
dimensions :-Diameter of boiler, 4 feet 8 in. height of boiler, 8 feet; diameter of furnace at crown-plate,
4 feet; diameter of furnace at bars, 4 feet 1 inch; height of crown-plate above bars, 20 inches; depth of
fire-bars, 4 inches; depth of ash-pit, 8 inches; depth of smoke-box, 12 inches; diameter of chimney, 12
inches. There are 547 tubes 1 inch diameter, and 52 inches long, of which a length of 34 inches only
passes through the water, and is alone reckoned as effective. The thickness of the shell of the boiler is
half an inch, and the plates are all double riveted; the pressure which the boiler is calculated to with-
stand is 80 pounds. The diameter of the cylinder is 12 inches; length of stroke, 18 inches; number of
revolutions per minute, 195; number of feet travelled by the piston per minute, 586. The area of a
cylinder 12 inches in diameter is 113.097 square inches; and if we take the effective pressure as before,
at 60 pounds, we have a force of 67858 urging the piston at a speed of 586 feet per minute, which
is equivalent to 3,976,490 pounds raised one foot high per minute, which, being divided by 33,000, gives
120 horses' power, which is just three times the nominal power. The weight of the boilers is about 611
cwt.; and the total weight of engine and boiler, with water in the boiler, is 90 cwt., or 21 cwt. per horse
power.
The engine is of the oscillating kind, and the shaft, crank, and framing for supporting the crank, are
all of polished malleable iron; the fly-wheel is very small, and is made with a polished rim, which also
answers for the drum upon which the belt runs that carries away the power. The governor is made in
the usual manner. The waste steam passes into the chimney, as in locomotive engines, whereby the
draught is 80 quickened that a small area of grate-bar suffices; but the end of the eduction pipe entering
the chimney is never contracted, as in locomotives. In the larger class of engines a platform is attached
to the boiler, to make the engine accessible to the engine-man, thus obviating the necessity of any
peculiar structure in the engine-house.
Galloway's direct-action engine.-This engine consists of two steam cylinders, the piston and rods of
which are attached by suitable links to a main cross-head or beam, connecting both engines; forming a
part of this cross-head are two triangular frames of wrought-iron, which, serving the double purpose of
side-rods and connecting-rods, descend one on each side of the cylinders, and they are connected imme-
diately with the cranks on the main shaft, lying between the cylinders in a line with the keel of the
vessel. The air-pumps are worked by the same arrangement of levers which forms the parallel motion
for the piston-rods; the hot water and bilge pumps are wrought by the air-pump cross-heads in the
usual way. The main shaft gives motion to the screw shaft through the medium of a new multiplying
geer. The engines are of 300-horse power, and every part of them is below the water line of the vessel.
There is extraordinary ingenuity in the whole of these arrangements; nevertheless this engine has
not come into use. The mode of operation of the multiplying geer is not easily comprehended, but the
principle of the arrangement may be explained to consist in such an arrangement of two cranks, of which
the one is twice the length of the other, that the movement of the crank-pin of the longer crank through
a semicircle will cause the crank-pin of the smaller crank to move through a whole circle. The prin-
ciple, however, will be made more clear by an extract from Mr. Galloway's specification, which we
therefore introduce.
1473.
1474.
1475.
1476.
CO
If the wheels shown in Fig. 1474 revolved upon axes in the usual way, a would make an entire
revolution, whilst b made only some portion of a revolution; but if b, instead of revolving upon an axis,
be suspended upon three cranks ccc, of equal length, and the radii of which are respectively equal to
one-half the difference between the diameters of the wheels, (calculating such diameters from the pitch-
lines and if the whole apparatus be at first in the position indicated by the drawing, thereby causing a
to revolve, it will be found that the cranks c, and consequently their axes, will make three revolutions
during the time that the inner wheel a makes one revolution. So if the proportionate diameters differ,
say as 2 to 8, or 4 to 5, or any other integral proportions, and the lengths of the cranks c be deter-
mined, then the cranks will always make as many more revolutions than the axis of a, as the diameter
of the driving-wheel a is to the difference between the diameter of the two wheels.
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But I propose, in most cases, as I have stated, instead of using toothed wheels, to adopt the arrange-
ment shown in Figs. 1474, 1475, and 1476, which I shall now explain :-Let it be supposed that three
equidistant points, ddd, Fig. 1473, could trace their path upon a plate or disk, attached to b, and
moving therewith, such path would be four epicycloids dotted thereon; and if to the points ddd, three
rollers, of equal diameter, were affixed, then a figure, eece, Fig. 1474, would be the tangent of the
said rollers in every part of their path; or, in other words, the rollers would trace out the figure eeee,
Fig. 1474; such being the case, it will be manifest that if, instead of toothed wheels, we adopt the
arrangement shown in Fig. 1474, where ddd are the three rollers, affixed to arms, and revolving in
bearings, and the figure eee, whose interior curved aperture is generated upon the principle I have
explained-then, on motion being given to the main axis, the cranks, dotted at cc, will make three
revolutions for one of the main axis; and if the figure be accurately constructed, and the cranks
truly proportioned, the action of the machine will be comparatively smooth and noiseless. In like
manner, if the circles or wheels a and b be in their diameters as 2 to 8, the figure fff, Fig. 1475, would
be generated, and by attaching the two rollers to the axis, as there shown, the velocity of the main axis
would be to the crank axis as 2 to 1; or, if the diameter of a and b be as 4 to 5, the figure Fig. 1476,
would be generated, and by constructing the apparatus, as shown at Fig. 1476, the relative velocities of
the main axis and crank axis will be as 4 to 1. I would further observe, that in whatever proportion
the multiplication be effected, it is necessary that the number of the rollers and of epicycloids should be
respectively equal to the number of times the generating circles can be divided by the difference
between the two diameters. It will also be manifest, that the multiplication effected by this method
does not admit of fractional quantities, but must always be in integral proportions. I must further
explain, that if one propeller only is intended to be used, one only of the three crank axes must be pro-
longed for that purpose; but if two propellers are intended to be applied, then two of the crank axes
should be similarly prolonged. It is further necessary to explain, that the arrangement of this con-
trivance may be changed by attaching the driving axis to the epicycloidal figure, and the cranks to the
part to which the rollers are attached; in which case the proportion of the multiplication will also be
changed, so that the cranks of Fig. 1474 would make three revolutions instead of two; those of Fig. 1475
would make four revolutions instead of three; and those of Fig. 1476 would make five revolutions
instead of four." This method of multiplying the speed of the screw-shaft, though most ingenious, is
likely to be rendered needless by the acceleration of the speed of the engine itself which is now
taking place.
Direct-action enginea-Direct-action engines have of late years come into extended use in steam
vessels, and their employment appears likely to become universal. They are less bulky and less
weighty than side-lever engines, and although most engineers resisted their introduction, these engines
have now, even in the engineering world, risen to considerable favor. Most of the early devices were
crude and unsatisfactory, but the excellent performance of the oscillating and double-cross-head engines
have redeemed the class from the disgrace that might otherwise have been expected to overtake it.
The existing crop of direct-action engines is divisible into five varieties the Gorgon, Siamese, Steeple,
Double-cross-head, and Oscillating.
Many nautical men, and some engineers, have objected to oscillating engines on account of the move-
ment of the cylinder, which they imagined would become a formidable evil in the case of a vessel roll-
ing heavily at sea. These objectors do not seem to have remarked that the rolling of the cylinder is
neither dependent upon, nor proportionate to, the rolling of the ship, but is regulated exclusively by the
movement of the piston; and it is difficult to see why a mass of matter, in the form of a cylinder, should
be more formidable or intractable in its movements than a similar quantity of matter in the form of a
side-lever, or in any other shape whatever. It has also been objected against the oscillating engine, that
the eduction passages are more tortuous than in common engines, so that the steam gets out of the
cylinder less freely. We do not believe such to be the fact, if the comparison be made with the com-
mon run of marine engines; and in practice, no diminution of efficacy from this cause is appreciable.
The fact is, all the objections that have been raised to the oscillating engine are merely hypothetical;
they are anticipations of defects to be found out in large engines on the oscillating plan, and would prob-
ably be plausible enough to carry some weight, were it not the fact, that they have been completely
controverted by experience. The remark, indeed, is heard sometimes even yet, that the oscillating
method may do very well for small engines, but is of doubtful efficacy for large ones. But the defini-
tion of large engines has been continually changed. to escape the contradiction experience afforded, and
that size is, in every case, decided to be large, which just exceeds the size of the oscillating engine last
constructed. The grounds of this skepticism, however, are now being fast contracted and, indeed, ex-
perience has now demolished every objection that theory had raised. Some persons have apprehended
that it would be difficult in large oscillating engines to obtain sufficient surface of trunnion to prevent
the trunnions from heating; yet we have never been able to learn that any heating of those bearings
has been found to occur in practice, and it appears probable that any such disposition would be resisted
by the cooling effect of the steam passing through them, which, though hot, is of greatly inferior tem-
perature to that of a hot bearing. It does not appear to us, however, that the trunnions may not be
made with any amount of surface that is thought desirable.
Rotary engines.-Rotary engines are engines for obtaining a motion round an axis by the direct
action of the steam, without involving the necessity of reciprocation. Some of them operate on the
principle of reaction, others operate on the principle of impulse; a third kind trusts to the intervention
of some liquid to produce the desired effect. It cannot be said that any one of the multitude of rotatory
engines yet tried has been completely successful. It is, of course, impossible that we can give any
enumeration, even, of the numberless schemes for rotatory engines that have at various times been pro-
jected, but we shall briefly describe a few of those which have attracted the most attention.
A rotary engine, designed by Hornblower, is represented in Figs. 1477, 1478, and 1479, and con-
sists of a steam vessel made of cast-iron, of the form of a globe, flattened at the poles. Fig. 1479 is a
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representation of the parts of the machine which move round within the steam vessel, and Fig. 1478
represents the interior of Fig. 1477, with its lid removed. The pipe A, Fig. 1477, receives the steam
from the boiler, to which is connected a valve-box, of any usual construction, by which to regulate the
admission of steam. At B the eduction pipe is connected, leading from the upper apartment to the
condensing apparatus, and turning in such a direction as may be most convenient for the discharging
pump to be wrought by the axle of the engine. DD is a middle part of the steam vessel, furnished
with flanges for the purpose of screwing it to EE, and also for receiving the lid; by which means the
partition within is secured to its place in the middle of the machine; and the lid may easily be removed
for the purpose of rectifying and repairing the internal structure. G is the square part of one end of
the axis of the machine, over which is placed a gland H, divided into parts, in order that it may be put
on over the square, and properly embrace the round part of the axis. Within this gland is a stuffing-
box, for the purpose of keeping the axle both air and steam tight. In one side of the lower apartment
of the steam vessel is a small opening, secured by a lid, for the purpose of cleaning that part of the
machine.
Fig. 1478 represents the partition within the steam
1477.
vessel, which may be made either of brass or iron, or
of both those metals combined. BB is the lower
flange, the upper part being taken away. CC are
the two openings or passages for the vanes: these the
E.
inventor calls vane-ports; and to reach a right concep-
tion of their figure, it may be explained, that the
largest vane-port is formed by the exterior portions of
D
B
two cones, and by a portion of the concave part of a
sphere. The extent of this passage throughout must
at least be equal to ninety degrees of a circle, and the
vanes must be of a sufficient width for two of them
always to make their entrance into the vane-ports
before the other two make their exit. The edge may,
therefore, be supposed to descend into the lower apart-
ment one-half of its depth, and to rise the other half to
meet the eye. The part E is formed spherically, and is
G
1478.
provided with a packing groove, which meets the edge
of metal in the middle of the vanes. FF is the main
axle of the machine, as well as the descending vane, by
which means both the nave and the vanes move steam-
@
tight in their revolutions. VVVV is that part of the
V
partition which forms a plane at the axis of the globe,
and is secured in its place by being seated in a rabbet
with the usual jointing materials on the interior margin
o
C
of the steam vessel. Two brasses, G G, are let down
B
into the partition, and they are raised or depressed by
screws, as occasion may require. The open vane ex-
hibits a frame of metal, which receives a plate on each
K
side: these plates, with the edge of metal K, cast with
the frame, form grooves and vacuities to receive the
0
packing.
Mr. Samuel Clegg's patent for a rotary engine is re-
1479.
presented in Figs. 1480, 1481, and 1482.
Fig. 1480 is the under side of a circular piece of
S
cast-iron, and of a diameter and thickness propor-
F
tioned to the size of the engine. I is the common
centre of the different circles shown on this piece.
With any convenient radius less than that of A A,
describe the circle CC, and within the latter the cir-
cles DD and EE, the radius of the latter being the
least of those now named. From the uses of these
parts, which will be immediately described, an idea
of their relative dimensions will readily be inferred.
Let that part of the surface AB, AB which is con-
tained between the circles A and C, be plain. Be-
tween the circles C and D sink a circular groove CD of any given depth: and between the circles D
and E let another circular groove be cut, of the breadth DE, and of any given depth less than that of
the groove CD. Let the remaining part of the surface A B, namely, that included between E and B,
be cut down to any depth less than the depth of the groove DE Into the groove CD let such a num-
ber of segments of a circle be fitted as shall form a complete circle, excepting the space at L, which is
occupied by adjusting screws or springs, to keep the segments close together. The segments are the
breadth (or nearly) of the groove CD, and of a depth less than that of the groove CD. Those sides of
them which apply to each other are to be ground together plain, and air-tight if possible. Their under-
surfaces, which are shown in Fig. 1480, are to be flat, 80 that the whole may form one complete plain
surface, excepting the space before mentioned, which is taken up by adjusting screws or springs L,
which screws or springs are placed so far below the surface as to let & roller pass by them, which will
be mentioned hereafter.
Fig. 1481 represents a vertical section of the plate and grooves of Fig. 1480, resting upon a circular
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ENGINE, VARIETIES OF THE STEAM.
chamber or hollow space Y Y, to which chamber the said plate forms a light covering, excepting that
space occupied by springs or screws LL, as before mentioned. I, the centre of all the grooves and
circles before described, is also the centre of the shaft. On the shaft I is fastened a plate or coupling Z,
in which is inserted a bar F. This bar may be of any given breadth, but in depth must be less than
that to which the circle EB was cut below the surface AB. To this bar is attached a wheel or roller
G, shown in Fig. 1482. The manner in which it is attached to the bar F is also there seen, and it is so
attached to it that the top of the wheel or roller G shall always be higher than the top of the bar F.
The wheel G being attached to the bar F, will, when the bar is made to revolve, describe a circular
path H HH, along the plain surface of the segments before described. c is the condenser, a the air-
pump, b the air-pump bucket, d the hot well, e the foot-valve, ff the cam which works the air-pump,
and r a roller resting thereupon. Let that portion of the plain surface of each segment, which answers
to the path of the roller G, be rounded off in such a manner as to make that portion of the surface an
are of a circle, the convex circumference of which is presented to the roller G. In Fig. 1482, at H, is
shown a perpendicular view of one of the segments, rounded off in the manner described, and present-
ing its convex circumference to the roller G. There may, likewise, be another roller attached to the
bar behind it, to lower down the segments in the same manner in which they are raised by the first
roller. Now it is obvious, all the said segments being in their places in the groove D, Fig. 1480, that
the roller G, in performing a revolution round the centre I, must travel along a series of convex arcs of
circles equal in number to the number of segments in the groove The groove D E is, in fact, a
recess in the deeper groove CD, and may, if necessary, be filled with hemp or tallow, or any other ma-
terial, which may answer the purpose intended.
It must be remembered that Fig. 1480 is a
1480.
view of the under side of the machinery. Fig.
1481 is a section of it, supposed to be in its proper
R
position, resting as a cover to the circular cham-
ber Y Y, and the segments resting upon a flat
facing 0 0. Each segment projects over the
facing 00 on both sides; their projection on one
side completes the cover over the hollow chamber,
and the other is the rounded surface for the roller
to lift them. The facing 00 is exactly, or as
nearly as can be, level with the under side of the
A
plate A B A B, when the plate is on its place, as
represented in Fig. 1481 80 that, when the seg-
ID
ments are all in their places, they complete the
semicircular chamber, and fit 80 close on their
seats and in the groove, that were the chamber to
be filled with any elastic fluid, they would pre-
vent its escape, or nearly, excepting where the
space is left for the springs or adjusting screws.
The use of these segments, which are what the
patentee claims as his invention, is as follows :-
Conceive a door or valve to be fitted in the hollow
chamber at Q, and a piston R, likewise fitted in the
chamber 80 as to move round in it, and the bar F made fast to the piston, on the side and in the man-
ner represented in Fig. 1480; then, if an elastic fluid of sufficient strength enters the chamber at N, it
will press equally against the door-valve and the piston; but the door or valve being immovable, and
the piston movable, the piston will be propelled forward in the circular chamber by the elastic fluid.
The bar F being fastened to the piston, and the roller G to the bar F, in the manner represented in Fig.
1482; and the roller being in motion with the bar and piston, the roller will lift the segments in suc-
cession as it comes in contact with them. The segments before the bar, being by this means lifted, allow
the bar to pass; and the operation being the same in all, the bar and piston make a complete revolu-
tion. Each segment, as soon as the bar leaves it, falls down by its own gravity, or by springs, or any
other contrivance, so that the opening which is made for the bar to pass is closed before the elastic fluid
reaches it; the elastic fluid being kept from the opening by the inner breadth of the piston exceeding
the outer diameter of each segment. The door or valve is lifted out of the way of the piston, when the
piston comes in contact with it, into the opening in the plate at N, a recess being made in that segment
which is opposite the door for that purpose; during which time the elastic fluid is shut out, but it enters
again when the door returns to its seat, and thus the operation continues. There is much ingenuity in
this contrivance: the principle on which the bar is enabled to pass the segments is nearly identical
with that introduced by Mr. Clegg into the atmospheric railway, for enabling the piston within the pipe
to be joined on to the carriages outside.
Our next example is Mr. Turner's rotary engine, patented in 1816. Fig. 1483 is a plan of the en-
gine, represented 80 as to show the internal structure. Fig. 1484 is another plan. Figs. 1485 and 1486
are sections, taken through the axis of the engine in different directions. A A, BB, CC, is the cylinder,
or external case of the engine, made in two or more parts, which are fastened together with screws, so
as to form a circular or annular passage, the transverse section of which is likewise circular, as shown
at EE, Figs. 1485 and 1486. The piston F, Fig. 1483, is accurately fitted into this circular passage,
and is caused to revolve therein by the pressure of the steam, which is applied behind it, or on the side
F, whilst a vacuum is made before it, or on the side G. The piston being connected with a central
plate G, which is fixed fast upon the axis or shaft H, the said shaft is put in motion; and by wheel-
work I, or any machinery which is best accupted, the power of the engine is communicated to any use-
ful purposes to which it is intended to be applied. The means by which the force of steam is made to
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561
produce the rotary motion is as follows:-Two valves or sliders, K and L, are applied at the opposite
sides of the annular passage or cylinder EE in the manner represented in Figs. 1483 and 1485. The
edge of the central plate G, which has the projecting arm to communicate with the piston, must be
made 80 that they can be made to shut up the passage of the cylinder EE, as represented at L, and
prevent the passage of the steam through
the same, or the slider may be opened,
as shown by the detted lines, to allow
the piston F to pass freely through the
cylinder. This is done by moving it
1481.
sideways on its centre 3 out of the eyl-
inder, into the box or case M, which IS
provided for its reception. The sliders
a
are put in motion by a communication
M
from the outside of the engine, 80 that
each one shall begin to open as soon as
S
the piston F approaches it, and shall be
Y
Y
completely opened whilst the piston
passes by, and that it shall then descend
again upon its seat. NO, Figs. 1483 and
1486, are two passages, through each of
which the steam is alternately introduced
and withdrawn from the cylinder. The
two passages are placed on opposite
sides of the centre of the engine, and are
provided with valves or cocks, which are
adapted to be opened and shut by the
action of the machinery in such succes-
sion, that when steam is entering from
the boiler into the cylinder at one pas-
sage, it shall be going out into the open
air, or to the condenser, at the opposite
passage. The mechanism which actuates
the slides K L, and the mechanism which
opens the valves for the admission and
exhaustion of the steam through the
passages N and O, act in concert with
each other, and in unison with the mo-
tion of the piston F; 80 that, as soon as
possible after the piston has passed by
T
the seat of a slider, the slider shall be
f
lowered down into its place ready to
close the passage of the cylinder behind
the piston. The instant the piston has
passed by the next opening, the steam
1482.
is admitted to flow through it, and act
between the slider and the piston, to
force the piston forwards in the cylinder
by its expansive force.
To explain the action of the engine
F
more clearly, suppose the parts in the
G
position in Fig. 1483; the slider L is shut,
and the steam is flowing, through the
passage O, into the space between the
slider L and the piston F; at the same
1483.
time the passage N is open to the condenser, to exhaust
the steam from the remaining part of the cylinder, and to
remove the pressure from the front side G of the piston.
In consequence, the pressure of the steam acting behind
the piston F, puts it in motion in the direction of the arrow,
and drives the arm of the central plate before it. The
slider K is now in the act of opening, and by the time
M
M
the projecting part of the plate G arrives at its seat, it
will be quite open into the box M, where it will remain
8
until the piston F has passed by its seat; it then begins to
G
descend, and by the time the piston arrives at the opening
of the passage N, the slider K will be completely shut
and stop the cylinder. The instant the piston has passed
over the opening of the passage N, the steam valves
are changed by the machinery, so as to admit the steam into the passage N, and also to allow the steam
to pass away, through the other passage 0, to the condenser; in consequence, the steam enters the
space between N and K, and thus, being behind the piston, drives it still forwards towards the slider L,
which immediately begins to rise by the action of the machinery, and as soon as the projecting part G
of the central plate approaches it, it will have retreated into the box M, leaving the cylinder free for the
71
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ENGINE, VARIETIES OF THE STEAM.
passage of the piston. Immediately after the piston has passed, the slider L descends again, and gets
settled to its place by the time the piston arrives at the opening 0; and the instant the piston has
passed over this opening, the steam valves are changed again; 80 that the steam will be admitted at 0,
behind the piston, and act between the slider L and the back of the piston, to force it forwards, which
is the same position represented in the figure. By this means the pressure of the steam is always made
to act behind the piston, and the vacuum is maintained before it. The sliders K and L are put in mo-
tion by levers 9 and 10, which are fitted on the outside of the boxes M, but move upon the same centre
pins 3, as the sliders move upon withinside the boxes, the levers being forked, as shown in the figure,
to reach on each side of the boxes; and the centre pins 3 pass through the sides of the boxes, and also
through both forks of the levers 9, 10, but do not turn round in the holes. To communicate motion
from the levers at the outsides of the boxes to the valves withinside, curved rods 11, 11, are carried
from the levers through the sides of the boxes M, and jointed to the arm of the sliders; stuffing-boxes
are formed round the rods to make tight fittings where they pass through the sides of the boxes M.
The ends of the levers 9, 10, are made to be included in an eccentric groove or rein ZY, fixed to the
central axis H. The form of this is shown in Fig. 1484, and is such as to hold the sliders shut, except
during the time that it is necessary to lift up the same to allow the piston to pass by. To make the
sliders fit steam-tight when they are shut, they are made rather larger than the diameter of the cylin-
der, and are received in grooves and made round in the inside, and the valves are ground against one
of the faces of each of these grooves, so that they will fit tight without any packing. The piston is
made of several segments put together, with springs behind them, to throw them out against the inside
surface of the cylinder, and it is thus made tight without any packing of hemp.
1484.
1486.
0
I
0
6
c
I
:
II
B
c
C
B
R
1485.
5
10
9
M
11
M
Q
Q
C
L
A
GL
K
O
We now come to the patent of Joseph Eve, taken out in 1825. Fig. 1487 presents an end section;
Fig. 1488 a longitudinal section of this engine. a a are the cylinder and cone, revolving in contact in
opposite directions, the cone having one groove, and being one-third of the diameter of the cylinder,
which latter has three wings or pistons ccc, the ends of which, as they revolve, touch the outer case e,
and do not admit any steam to pass. The steam is admitted through the pipe f, and acting on the
wing c, causes the cylinder to revolve until the said wing passes the pipe g, when the volute of steain
lodged betweeen each two wings, is allowed to escape. The wing, which has thus passed, falls into the
groove d of the cone, the bottom of which groove it touches in passing, thus allowing no steam to escape
between. The said wing c then passes again by the steam pipe f, and is acted upon as before de-
scribed, and 80 on in rotation. The cylinder a, which is firmly fixed to its axis b, rests on one side on
the outer case e, through which the axis projects; but as there is some friction produced by the revolu-
tion of the cylinder at its two ends touching the outer case, a false end hh is placed under the opposite
end of the cylinder, which false end slides on the axis b freely, and has a thread cut at the end, by
means of which, and the adjusting nut i, the cylinder, if worn at the two ends, can be easily tightened
and adjusted. The adjusting nut is confined by the collar k, which collar is screwed to the outer case.
The conical shape of the small runner, which can likewise be moved upwards or dow nwards in the outer
case, serves to keep the two convex surfaces of the cylinder and cone in contact. The groove d, in the
conical runner, is cut into a separate piece of metal, which slides by an adjusting SCI ew o, up and down:
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563
90 that when the engine is adjusted, the groove d, on the piece of metal, into which the said groove is
cut, can be moved up and down, 80 as to fit the wings of the cylinder. Letters nn, in Fig. 1488, re-
present two cog-wheels running into each other, attached on the outside of the engine to the axis of the
cylinder and cone, placed there for the purpose of producing a corresponding revolution of the said
cylinder and cone, thus causing the groove of the cone to present itself regularly to the wings of the
cylinder; o is a pinion fixed to the other end of the axis, by means of which any machinery can be put
in motion.
1491.
1487.
b
Oa
c
a
a
b
e
m
1492.
1488.
n
n
e
c
a
a
1
€
b
K
b
/
i
i
0
1495.
1489.
N
%
r
e
e
1490.
h
1
P
M
g
b
Another variety of steam-engine on this principle is shown by an end section view in Fig. 1491, and
an external view in Fig. 1492. This engine has a cylinder with two small conical runners on each side,
the said conical runners being of the same construction as before described, with one groove cut into
each, and being one third of the diameter of the cylinder. There are two induction and two eduction
steam pipes; and although the engine may be, with the exception of the addition of one of the conical
runners, exactly of the same size as the one first described, a double quantity of steam is requisite, and
twice the power of the former engine is gained: the steam enters through the pipe fa, and acts on the
wing c, which, after having passed the pipe go, where the steam escapes, falls into the groove d, of the
lower cone, and appearing at the induction steam pipe fb, is loaded again with steam pressure, which
it discharges at the second eduction pipe go, and then enters the groove of the upper cone, which
having passed, it is loaded again at the first-mentioned induction pipe. Letters mm are bridges by
which the spindles or axes 666 are supported. This engine has three cog-wheels, nnn, attached to
the three spindles, 80 as to cause the cylinder and cones to revolve in unison, and, like the first-described
engine, has a pinion o on the opposite end of the axis of the cylinder. Fig. 1493 shows'an end section,
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ENGINE, VARIETIES OF THE STEAM.
Fig. 1494, a longitudinal section, and Fig. 1495, the exterior of another form of this engine, in which
there are two rollers. The conical runners, in this case, are of an equal length and diameter; each has
two wings or pistons attached, and two grooves cut into it, and in revolving in opposite directions, the
wing of one runner falls alternately into the groove of the other. The steam enters by pipe f, and
as the cylinders are running in contact, it cannot escape
between them, but acts upon the two wings in oppo-
1493.
site directions, and escapes at the eduction pipe g, after
the said wings have passed the same. By reference to
Fig. 1494, which represents a longitudinal section, it will
be seen that the two cones have each two false ends hh,
sliding freely on their spindles; the two outer cases ee, fit
over the runners and their wings exactly; each of the four
a
false ends has an adjusting nut, by which the engine is
tightened if steam should escape, or slackened if it should
d
d
run too tight. Each pair of the false ends, where they join,
have a plate that connects them and breaks their joints, 60
as to prevent an escape of steam; this plate h alides into
the groove r, cut out of the false ends, as exhibited by Fig.
1489 and Fig. 1490, the former showing an end view of the
false ends with the connecting plate in the middle. On
these false ends packing rings, g gg, which are confined to
the sliding plate, as exhibited in the latter figure, are
placed. These rings press against the hollow outer cases,
1494.
and prevent any steam escaping by them. These packing
rings are shown in section, in Fig. 1494. It will be evident
that the false ends need not be made true, if the connecting
plates and packing rings, as above described, be adopted,
and that the engine, if provided with movable false ends,
conical runners, and the afore-described connecting plates,
and packing rings attached, as shown in Fig. 1494, can
always be kept steam-tight, and by use the various parts,
on which there is any friction, will fit better."
Fig. 1496 (A) is Beale's rotary engine, in which the steam
is admitted on the one side of an eccentric frame, armed
with rollers, which serve the place of pistons; and the cen-
trifugal force is reckoned capable of keeping the rollers
against the interior of the cylinder. An engine upon this
plan has been put into a steam vessel, but its success has
not been such as to induce its more extended adoption.
1.
Fig. 1496 (B) is the engine specified in the last patent of the
Earl of Dundonald, and which has been introduced in the steam frigate Janus." It is not very cor-
rectly represented in the accompanying sketch, which is copied from the rough drawing given in his
specification. This plan very much resembles that contrived by Watt, except that an eccentric is sub-
stituted for a leaf, and a ball and socket joint is introduced in order to enable the steam and exhaustion
1496.
A
B
doors to make a steam-tight junction with the eccentric. This contrivance has not as yet realized any
great success, and the prevailing opinion among engineers.appears to be, that it will not supersede
ordinary engines. Similar engines have been tried on many former occasions, but they have been always
found to involve either a ruinous amount of leakage, or such a degree of friction as to make the plan
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impossible in practice. These difficulties will probably be abated as the resources of workmanship
increase; but they exist at the present time, and have proved fatal to nearly the whole tribe of rotary
engines.
1497.
Threttle
?
adid
SCALE.-1 inch=1 foot.
Fig. 1498 is a rotary engine invented by Mr. Yule, and he has had it in operation, working
smoothly for some years. It consists of a cylinder C, in which, upon the axis A, revolves another
eccentric cylinder B, fitting tightly by means of packing at the line of contact. D is a diaphragm.
which slides vertically in strong guides and rests upon the upper side of the revolving piston B. The
steam is admitted by either of the pipes S'S', according to the direction the engine is intended to
revolve in, the slide valves at the lower end of the steam pipes being regulated accordingly. E is the
eduction pipe. In the figure the steam is represented as entering by the steam pipe S', the valve of
which covers the eduction port, and admits the steam to press upon the diaphragm D, and the piston B.
The steam from the pipe S2 is at the same time shut off, and the eduction on that side of the piston
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ENGINE, VARIETIES OF THE STEAM.
opened, and there being nothing to counterbalance the pressure of the steam on the other side of the
piston, and the diaphragm being incapable of any internal movement, the piston B is made to revolve
in the direction of the eduction port. If motion in the contrary direction be desired, it is only uncessary
to reverse the valves.
American engines.-The performance of the American steam vessels is such as to make them more
than a match in point of speed to the best steam vessels of English construction. Their efficient
performance is partly perhaps due to the high pressure of steam employed, and partly to the pecu-
liarities of American river navigation, which are such as to enable a large sized vessel to subsist
with a very moderate draft of water. On the Mississippi and
its tributaries most of the engines employed are of the high-
1498.
pressure kind a hundred pounds upon the square inch is
esteemed a moderate pressure, and sometimes the pressure is
raised as high as 200 pounds on the inch. The engines employed
in the vessels on the Hudson and other Eastern rivers are for the
most part condensing engines. Some of them have horizontal or
inclined cylinders; in other cases the cylinder is placed above the
shaft, with side-rods extending from the ends of a cylinder cross-
head to cranks on the shaft beneath; while in most a beam is
employed as in the ordinary land rotative engine. Two engines
S2
is
are generally employed; but sometimes only one, the crank being
carried over the centre by the momentum of the vessel.
In the preceding page, Fig. 1497, will be seen a view of the ma-
chinery of THE NORTH AMERICA;" and we may here set down a
few of the chief dimensions :-Diameter of cylinder, 43 inches
length of stroke, 11 feet; length of keel, 200 feet; breadth of beam,
25 feet; diameter of paddle-wheel, 27 feet; length of float, 10 feet
dip of float, 27 inches; pressure of steam. 50 pounds.
The framing of this engine is of timber; the working beam
0
consists of a cast-iron skeleton frame, trussed with wrought-iron;
and the crank and connecting-rod are both trussed with malleable
iron rods. The beam is very short in proportion to the length of
C
the stroke, and the place of the parallel motion is supplied by
guides, the piston-rod being coupled to the beam by a long link,
C
to enable the guides to operate efficiently. The several pieces
B
composing the wooden framework which supports the crank-
shaft are keyed together with wooden keys, and bound with iron
knees and plates of iron, to make the whole stiff and firm. The
E
valves are double spindle-valves, 80 that they are kept in equi-
librium. The cut-off or expansion-valve consists of a disk turning
on a centre, like the throttle-valve, and set in the steam pipe, which it exactly fills when closed in the
rest of the engine there is little that is peculiar. The trussed beam is adopted with advantage in all
large beam engines, as it is not merely lighter than the entire cast-iron beams, but stronger and more
safe.
The saloons of most American steamers are magnificently fitted up: many of them are upwards
of 150 feet long, 20 feet wide, and 12 feet high; and the accommodations are in every respect most
complete and commodious. The paddle-wheels are generally entirely constructed of wood, with the ex-
ception of the centres, to which the arms are bolted, and which are of cast-iron. The usual number of
strokes per minute, with an 11 feet stroke, is from 25 to 27, so that the piston travels at a great velo-
city. In the vessels on the Mississippi the paddles are made with a clutch or friction-strap, 80 that they
may be thrown out of geer, and the engines may be turned so as to feed the boilers when the vessel is
alongside a wharf, without moving the paddle-wheels.
The engine of the steamboat New World, constructed to run on the Hudson river from New York to
Albany.-The steamboats which navigate the lakes and rivers of this country are perhaps among the
most striking of the many evidences of American ingenuity and enterprise that present themselves to
the notice of the European traveller. Their dimensions far exceed those of the steamboats constructed
in Europe, and the extent of their internal accommodations corresponds to that of their external propor-
tions, whilst the very high speed which they attain is almost, if not altogether, unrivalled elsewhere.
The magnificent first-class steamboats at present in operation on the Hudson river and Long Island
sound are of comparatively modern construction, dating back but seven or eight years; but during each
successive year new vessels have been built, which have surpassed their predecessors in size, power,
and in the splendor of their decorations, while they possess every improvement that the skill, taste, and
experience of their constructors could devise. There exists, nevertheless, in the general external ap-
pearance of the boats, a great similarity, and this similarity extends both to the details of their construc-
tion and of that of their machinery, and also in some degree to their form or model. The general fea-
tures of this latter are, great proportion of length to beam, a shallow hold, and a long flat floor, which
extends almost to the extremities of the boat. Great buoyancy, and consequently a very light draught
of water, are by these means secured. Experience has demonstrated the advantages of attempting to
go over rather than through the water when very high speed is desired to be attained.
The absolutely best form of model. and that which under all circumstances is subject to the least
average resistance, is still a matter of speculation and experiment, and every builder has opinions and
theories of his own, differing more or less from those entertained by his brethren of the craft. The
rivalry which exists has, however, been productive of extraordinary results, 80 that a sustained speed
of 20 miles per hour is not now uncommon; and these astonishing performances are to be attributed
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partly to the improved form and fineness of the water lines, and partly to the great size and power of
the engines constructed within the last few years.
To avoid overloading the boat, it is absolutely essential that the motive power be obtained with com-
paratively little weight of material, and this requirement is admirably fulfilled by the " American Boat
Engine." Its characteristic peculiarities are, the long stroke and prodigious velocity of the steam piston,
the use of steam of 8 high pressure, together with expansion and condensation. A large effective power
is thus developed by a machine, the aggregate weight of whose parts is comparatively small.
Moreover, from the great tenacity and strength of the American iron, the constructor is enabled to
give to his engine proportions considerably lighter than would be deemed safe in Europe. The im-
mense diameter of the paddle-wheels is worthy of note as an element of no small importance in the
economical expenditure of the power developed by the engine, and consequently in its effect on the
speed of the boat.
Nearly all the largest class engines are on the beam plan, like that of the New World. Many of the
second class and smaller boats have cross-headed, or, as they are termed, square engines. In this ar-
rangement the cylinder is situated directly over the paddle-shaft and cranks, to which motion is com-
municated by side-rods from the cross-head. The air and feed pumps are worked by a separate beam,
which is connected with the cross-head by means of appropriate links. There are several examples of
inclined and horizontal engines; of the latter kind, two or three of tolerably large size. The John Ste-
vens, now on the Delaware river, and the John Potter, of New York, have steeple engines. With very
few exceptions the engines are all single, and are situated in the middle of the boat. In the existing
instances of double engines, there are no connecting shafts, but each cylinder works separately one paddle-
wheel. In the construction of all these engines, or at least of their framing, wood is largely employed,
its cheapness, as well as the facility with which it is worked, being strong recommendations to its use.
The gigantic engine, which is very fully elucidated in detail in the accompanying engravings, was
completed and put into operation in the early part of the summer of 1849. It is larger and more pow-
erful than any hitherto constructed, and from the late date of its completion, it may be regarded as an
example of the American River Boat Engine in its most perfected form. It was built by the well-
known firm of T. F. Secor and Co. With the following description of the engine in detail will be cou-
pled remarks explanatory of any important differences of arrangement or construction existing in other
engines.
The Bed-plate is a single casting, and forms the foundation of the heavier portions of the engine. It
is carefully fitted upon the keelsons of the boat, and is firmly secured by numerous holding-down bolts
of large dimensions. That part of the plate which lies between the keelsons forms the channel-way or
passage from the condenser to the air-pump. In the centre of this passage are the foot-valves.
The Foot-valves are of the ordinary description. They are four in number, and, with their seats, are
made of cast brass. They are fitted down, metal to metal, to their seats in the bed-plate, and are se-
cured by brass keys. A removable bonnet over them admits of a ready access, for the purpose of
adjustment or repairs.
The Condenser is of a cylindrical form, flanged at both ends, of the same diameter as the steam cylin-
der, by 6 feet 6 inches in height; its content is therefore about 13-30th of that of the space through
which the piston passes during one stroke. The upper extremity is cast close, the lower end is open,
and is fitted down to the chipping-fillets on the bed-plate, to which it is firmly bolted and secured by a
rust joint. Near the top of the condenser, and in the front of it, is the exhaust steam branch, a long ob-
long opening, corresponding to that on the lower steam-chest, to which it is attached. A small branch
admits the injection water, which flows upwards through a curved elbow pipe within the condenser.
Encircling this pipe, is a circular perforated plate, upon which the water falls in its descent, and becomes
dispersed throughout the condenser. On the sides of the condenser, and running in an inclined direc-
tion, strongly bracketed webs or flanges are cast, to which the wooden framing that supports the main
beam is fastened by bolts and keys.
The Injection-valves are of the ordinary conical form, and are worked by screws, which are connected
by light spur-geering to hand-wheels, conveniently placed within reach of the engineer. The injection
supply-pipes are of copper, and lead directly to the valves from the bottom of the boat.
The Cylinder-bottom is a circular flanged cast-
ing, containing the lower steam-port. It forms
1498(s).
the connection between the cylinder and the con-
denser, to both of which it is fitted and bolted.
The Steam-cylinder is secured to its bottom
by a rust joint. It stands vertically over the
condenser, and has its upper end steadied by
horizontal stays to the framing. Its bored di-
ameter is 76 inches. Fig. 1498 (a) is a section of
guide for cross-head, showing the foot which is
bolted on the cylinder flange.
The Piston is a hollow casting of iron, strengthened by radiating arms, and also by two wrought-iron
bands, which are bored and shrunk upon it. The application of these bands is a recent improvement,
by which great additional strength and security are given to the piston. The steam packing is of cast-
iron, and consists of three rings, two external, and one internal, whose depth equals that of the other
two combined. These rings are all ground to the piston, and to each other. The packing is pressed
out by a great number of short elliptical steel springs, which are placed close together round the entire
circumference of the body of the piston.
The Cylinder-cover is a hollow casting, ribbed similarly to the piston. Its upper surface is turned
and polished bright. Circular holes are formed between the ribs, for the support and subsequent ex-
traction of the core, and these holes are afterwards closed with turned stoppers of cast-iron.
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ENGINE, VARIETIES OF THE STEAM.
The Steam-chests are large and capacious castings of iron, containing the valves and seats, and the in-
let and outlet steam passages. On the upper chest is cast the throttle-valve pipe, to which is attached
the supply steam-pipe, leading from the boilers. On the bottom chest the exhaust branch is cast,
through which the waste steam passes to the condenser. The valve-bonnets and glands are turned and
polished bright. The chests are rust jointed to the upper and lower steam-ports of the eylinder.
The Side-pipes, which connect the steam-chests, are of cast-iron, ornamented with numerous bands
and mouldings, and turned and polished bright throughout their entire length. At the upper end of each
pipe is an expansion-ring of thin copper, which, by its yielding, compensates for any slight elongation
or contraction of the side-pipes, occasioned by heating and cooling.
The Valves which govern the entrance and exit of the steam are of a circular form, connected together
in pairs, and of the kind called double balance-valves, from the fact that the downward pressure on one
valve is balanced, or nearly so, by the upward pressure on the other valve of the same pair. The upper
valve of each pair on the steam side, and the lower one of each pair of the exhaust, are a little larger
than the others, and, consequently, there exists a small amount of unbalanced pressure, which effectually
retains the valves in their seats, and insures their tightness. The valve-seats are formed by boring out
the metal of the steam-chests, and the valves are fitted into their places by turning and subsequent
grinding with emery and glass-powder. This is an operation requiring great care and skill, as it is ab-
solutely necessary that the valves bear uniformly on both beats, 80 that there may be no leakage of
steam. The taper or cone of the valves and seats is a matter of considerable importance; from I inch
to I inch in the diameter, for every inch in depth, is a good proportion The valves themselves are of
brass. The connecting piece of each pair is made of cast-iron, in order to insure, by its expanding uni-
formly with the steam-chest, the accurate fit of both valves when hot. Engines working in perfectly
fresh water have their valves altogether of cast-iron, and in these cases both valves and connecting
pieces are cast together; excepting, however, the lower exhaust-valves of each pair, which are kept
separately, because, from their larger diameter, they cannot pass through the upper seat, and conse-
quently they have to be introduced either through the steam-port, or through an opening formed in the
back of the chest, and then connected with their upper valves.
Where salt water is largely or exclusively used in the boilers, not only the valves but their beats also
are made of brass. These are fitted into the chests by turning and boring, and they are then firmly se-
cured by turning over and riveting the under edges, which have been previously rendered this and
sharp, to facilitate this operation. The combined area of the two valves in each pair is about equal to
the area of the side-pipe, which is between fth and 1-9th of that of the steam-cylinder. Engines whose
pistons move more slowly have proportionately smaller openings for the admission and exit of the steam.
The valve-spindles are made either of cast-steel or of the very best wrought-iron. The spindle passes
completely through both valves and their connecting piece, and the lower extremity works in a guide,
which is a separate casting, bolted to the steam-chest, or when brass beats are used, it is cast with the
lower one. The valve-spindles pass upwards through stuffing-boxes in the steam-chest covers to the
lifters by which they are worked.
The Valve-geering consists of the lifter-rods with their lifters, and the rock-shafts with their levers.
There are four lifter-rods, which are turned bars of wrought-iron, placed in front of the steam-chesta.
They are made to move vertically up and down through guides which are cast or bolted to the chests
and side-pipes. On the lifter-rods are keyed eight projecting arms, called lifters. Four of these em-
brace the extremities of the valve-spindles, which are screwed, and provided with double jam-nute.
The spindles pass quite loosely through the ends of the lifters, and the jam-nuts are adjusted so as not
to bind them there is thus an allowance made for any slight lateral motion which inaccuracy of adjust-
ment or wear of guides may render requisite. The four remaining lifters are likewise keyed upon the
roda, and they are placed directly over the levers on the rock-shafts, from which they receive their mo-
tion. There are two rock-shafts, one for the steam and one for the exhaust-valves, and they are worked
by separate eccentrics. On the shafts there are four levers, by which the lifters and rods are raised,
and they are curved on their working faces, 80 that their action is rendered perfectly smooth and noise-
less. By the reciprocating or rocking motion of the shafts, the lifter-rods, and with them the valves,
are alternately raised and lowered. The exhaust-valve levers are of a length just sufficient to give the
requisite amount of lift and lead, and they are so adjusted on their rock-shaft, that the moment one rod
is fairly down, the raising of the other commences. The steam levers are considerably longer, and are
placed upon their rock-shaft in a position inclined to one another, 80 that an interval, longer or shorter,
occurs between the falling of one rod and the rising of the other. During this interval both valves are
down, and the steam is of course shut off from the piston. This apparatus then constitutes the expan-
sive or cut-off geering, and it may be varied at pleasure, by simultaneously adjusting the respective po-
sitions of the eccentric on the paddle-shaft, of the two levers on the rock-shaft, and of the pin in the
eccentric lever. This latter has a slot in it, in which the pin travels, 80 that it can be moved to or from
the shaft, and fixed as required. By advancing the eccentric, and lowering the extremities of the levers,
the steam will be earlier cut off, and vice versa. The amount of lift may be regulated by moving the
eccentric pin. The movement of the rock-shaft in the interval during which the valves are down is very
considerable, especially in a high expansion, and this, added to the additional amount of movement by
which the valves are lifted the requisite height, makes the total angular motion of the rock-shaft very
great, and therefore an eccentric of corresponding throw is required. The steam eccentric has conse-
quently a throw of 91 inches each way, giving a travel of 19 inches to the rod. The exhaust eocentric
throws 51 inches, giving 11 inches travel. The expansive geer above described is called "Stevens's
cut-off," and it is the one employed in the engine of the New World. Another variety of geer in fre-
quent use has but one rock-shaft and eccentric, with but two lifter-rods. The exhaust lifters and their
action are precisely the same as in the geer already described. The steam lifters, which are, like the
others, keyed to the rod. have spring catches fitted at their extremities, which lock into the valve-spin-
dles when down, and which are released at the proper time, by coming in contact either with an adjust-
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ENGINE, VARIETIES OF THE STEAM.
569
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570
ENGINE, VARIETIES OF THE STEAM.
able stop, or with a reciprocating arm, moved by the engine. The valves then fall by their own weight.
To prevent damage arising from the concussion, a contrivance called the dash-pot is made use of this
consists of a small cylinder containing water, and a piston which fits it loosely, and is attached to the
valve-stem. The height of the water is 80 adjusted that the piston touches or dashes upon it before the
valve reaches its seat: the momentum is thus effectually overcome, and injury to the surfaces of contact
completely prevented. The expansion-valve of many of the older engines is simply a throttle-valve.
worked by cams on the paddle-shaft. The rock-shaft, lifters, and levers are of cast-iron, turned and
finished bright. The outer supports of the rock-shafts are bolted to the side-pipes, and the middle sup-
port, which is common to both shafts, is fastened to brackets cast on the cylinder.
The Hand rock-shaft, or trip-shaft, is a small shaft of wrought-iron working in bearings cast on the
lower steam-chest. It has projections welded upon it, corresponding to similar ones on the lifter-rods,
and its reciprocating motion raises and lowers the valves precisely in the same manner as in the large
rock-shafts. Sockets are formed in the trip-shaft, into which the starting-handle is inserted. The lever-
age of this is considerable, whilst the resistance amounts to but little more than the weight of the
lifter-rods, valves, and their appendages; consequently the handling of the engine is performed with
great facility.
The whole front of the engine, consisting of the chests, side-pipes, geers, and the various handles. is
highly finished and ornamented, and the profusion of bright work gives it a very showy appearance.
Between the side-pipes are placed the clock, counter, steam and vacuum gages, which are very hand-
somely mounted, and supported by an ornamental framework of cast-iron.
The Eccentrics are of cast-iron, turned, bored, and fixed in their places on the paddle-shaft by means
of keys and set-screws.
The Eccentric-bands and rods are of wrought-iron. The latter are in two lengths, supported at the
junction by a pendulum link, which vibrates on a stud fixed to the framing of the engine. The chief
portion of the weight of the rod is thus supported, so that the eccentric-hook is very easily disengaged
from the pin in the rock-shaft lever. The unhooking geer is a simple arrangement of rods and levers,
by means of which the engineer throws out the eccentric-rod hooks.
The Piston-rod, cross-head, and cap are of wrought-iron. The guide-blocks, which are of brass, lined
with Babbit's metal, are retained by jaws bolted to the extremities of the cross-head. The upper ends
of the guide-blocks, projecting above the jaws, are cast hollow, and form very convenient oil-cups.
The Guides are of cast-iron, bolted at the bottom to the cylinder-flange, and at the top to a light
casting which connects them laterally. Braces of wrought-iron, running horizontally from the framing
to the guides, retain them in their truly vertical position.
The Air-pump is fitted and bolted to the bed-plate directly behind the condenser; it is of cast-iron,
and is lined with brass. The lining is cast in narrow pieces, the edges of which are planed; they are
then placed, like the staves of a cask, all round the interior of the pump, which is previously bored out.
The last piece is driven in very tightly, and the entire lining then undergoes a severe and continued
hammering, by which the metal is condensed, the joints closed, and the brass and cast-iron forced into
intimate contact. A second boring completes the pump. The upper flange of the air-pump is made of
large diameter, in order to receive the reservoir which stands directly upon it, and is secured to it by a
faucet-joint.
The Air-bucket and valves are of cast brass. The valves are of the kind called butterfly-valves, and
have hinges somewhat longer than the valves which work in corresponding grooves cast in the face of
the bucket. The guard which limits the lift of the valves is of brass; it is bored out and slipped over
the rod, and bolted down to the bucket. The bucket is provided with a loose junk-ring, fastened with
copper bolts.
The Air-pump rod is of wrought-iron, sheathed with brass, which is cast around it. Its lower end is
turned of a conical form to suit the eye of the bucket, to which it is fastened by a brass key.
The Discharge or delivery valve is a dome-shaped casting of iron, having in its centre a deep stuffing-
box, through which the rod works. A groove is turned out in the lower edge of the valve, and this
groove is filled up with wood. This wood forms the beat of the valve, and it works upon a faced ring,
cast on the upper end of the air-pump.
The Reservoir or hot-well is a large cylindrical casting, standing upon the upper flange of the air-
pump. It has a cover on the top, with a stuffing-box, through which the rod works.
The Air-pump cap, cross-head, and guides are of the same form and construction as those of the steam-
cylinder.
The Feed-pumps are two in number, and stand on each side of the air-pump, under its broad upper
flange; they consist of the barrels, valve-chambers, and buckets, with their rods. The valve-chambers
are square castings of iron, which are bolted to projecting brackets cast on the air-pump; they contain
the brass flap-valves, to which there are appropriate bonnets. The barrels are plain cylinders of brass,
bored out truly cylindrical; they are cemented at the lower end into faucets cast on the valve-cham-
bera, and at the upper end to faucets in the flange of the air-pump. The buckets or plungers are of
brass, and are keyed fast to wrought-iron rods which pass through stuffing-boxes in the cover of the
reservoir to the air-pump cross-head, to which they are attached.
The Front links which connect the cross-head with the working-beam are of wrought-iron, and with
their straps, cotters, and brasses, are finished bright.
The Air-pump links are similarly fitted up and finished.
The Working beam is composed of a skeleton frame of cast-iron, round which a wrought-iron strap of
great strength is fixed. This strap is forged in one piece, and its extreme ends are formed into large
eyes, which are bored out to receive the end journals. The skeleton frame is a single casting in the
form of a cross, and it contains the eyes for the main centre and air-pump journal. The centre eye is
strengthened by wrought-iron hoops which are shrunk upon it. At the points of contact of the strap
and skeleton, key-beds are prepared, into which the keys are carefully fitted and tightly driven. The
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ENGINE, VARIETIES OF THE STEAM.
571
keys are afterwards riveted over at both ends. By this they are retained in their places, as well as the
strap on the skeleton frame. The strap is likewise secured to the frame by small straps and keys. The
skeleton frame is still further braced by straps with cotters and gibs, which tie the middle of the long
arms of the cross to the extremities of the shorter arms.
The Beam-journals are all of wrought-iron, secured in the working-beam by keys.
The Connecting-rod is of wrought-iron. It is forked at its upper extremity and single at the crank-
pin end. It is stiffened by a double truss-brace of round iron, which is secured by bolts to the rod near
each end, and passes over a strut at the centre. This strut is screwed and furnished with nuts, by
which the brace is tightened. The rod and its appurtenances are finished bright, in the same style as
the front links.
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The Cranks are of wrought-iron, bored out and shrunk upon the shafts. Cast-iron cranks, strapped
with wrought-iron, are very commonly employed on account of their less first cost.
The Crank-pin of wrought-iron is keyed fast into a conical hole in the eye of one crank. The other
end of the pin is planed square, and passes into a parallel hole in the other crank. In the four seg-
mental spaces thus left between the pin and crank-eye, wedges are fitted, and these are retained in
their places by a washer bolted to the end of the pin. This arrangement permits the pin to accommo-
date itself to any relative motion of the two cranks which the falling of the shaft sooner or later
produces: it also facilitates the adjustment of the pin, which is effected by slipping sheet-iron packing
under the wedges.
The Paddle-shafts are of wrought-iron.
The Shaft-bearings or pillow-blocks are bracketed castings, formed to suit the angles of the wooden
framing on which they lie. They are fitted with the usual brasses, which are lined with Babbit's metal.
The holding-down bolts, by which the pillow-blocks are secured, are arranged in a radiating direction
from the centre, so that they embrace a considerable exteut of the floors and keelsons.
The Outer-bearings are simple plummer-blocks, fitte with brasses, and resting on frames which are
raised upon the guard-beama
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ENGINE, VARIETIES OF THE STEAM.
The Spring-bearing is a mere cushion of brass, which is placed to support the shaft just within the
wheel, in order to prevent vibration. It is occasionally supported on springs.
The Pillow-blocks of the main centre of the working-beam are similarly made with those of the shaft,
and are fastened by strap-bolts attached to the wooden framing, and also by bolts extending right down
to the floor timbers of the boat.
The Water-wheels are made up of the centres, arms, and buckets.
The centres are circular bracketed castings of iron, to which the arms are fitted and bolted; they are
bored out to fit the shaft, and secured by eight keys in each. The arms and rims are of wrought-iron,
fastened to each other and to the centres by riveting they are braced laterally by round iron stays,
fastened in the form of a cross between the outer arms of each set. There are nineteen sets of three
arms in each wheel.
The Floats or buckets are of wood, and there are thirty-eight in each wheel, attached to the arms by
hook-bolts.
Various forms of wheel are in use: some have the single bucket, as the New World; in others the
float-board is divided, sometimes in the direction of its length, and in other cases in that of its width.
Iron arms, though much lighter, are more expensive than wooden ones, and are but seldom employed.
Wooden arms, moreover, are more readily repaired when fractured by ice, floating timber, or other
causes, and such fractures are of frequent occurrence at certain seasons of the year. The divided
buckets tend greatly to the smooth and equable motion of the engine, especially in rough water, although
the full board will give a somewhat higher speed in water perfectly smooth. The wheels of the New
World are the largest ever made, being upwards of 45 feet in diameter.
The Framework of the engine is composed of four pieces of pine-wood, which are formed into two
triangles, inclined laterally to each other. Their lower ends rest upon the keelsons, and upon their
upper extremities are placed the pillow-blocks of the working-beam. They are very solidly fastened
together and to the boat by numerous horizontal and diagonal timbers, which are secured by wooden
knees and keys, and are heavily bolted The two front legs of the framing are bolted and keyed to the
diagonal flanges cast on the sides of the condenser. At the other end, the framing is attached to the
large mass of timbers which support the shaft pillow-blocks. The framing is further steadied by two
additional timbers running from the beam pillow-blocks outside the shaft to the keelsons of the boat.
The entire fastening of the engine and of its framing is 80 disposed as to reduce all the strains to direct
ones of extension or compression on the fibres of the iron and wood employed in the construction.
The Boilers are on what is termed the single return plan, that is, the flame and heated gases make
but one change of direction in their progress from the furnace to the smoke-pipe. The latter is directly
over the furnace, at which the flues commence and lead directly to the space or connection at the back
of the boiler; from thence another set of flues over the first runs straight to the smoke-pipe. The shell,
the upper part of the front, and the flues are all circular, and therefore require no staying. On all flat
surfaces, screw, socket, or crow-feet stays, are placed every eight or nine inches apart. The smoke up-
take is likewise stayed to the steam-drum by socket-bolts. In the construction of these boilers no angle
iron is used, but the plates are everywhere bent to form the junctions at the angles, and the flue-heads
are worked out into collars, into which the flues are inserted and riveted. The excellent qualities of the
Pennsylvania iron enable this bending to be performed with safety and ease. Except at the junction of
the shell and front part, there is no double riveting. With unimportant differences of detail, the great
majority of the boilers made and used in and about New York are of the same general form and con-
struction. Tubular boilers on various plans have been and still are occasionally employed, but they
have bitherto met with no very extensive adoption. The New World has two boilers, and they are
placed on the guards of the boat, abaft of the wheel-houses. The front part of the boilers rests on a bed
of putty laid directly on the deck, and the shells are supported by appropriate saddles of cast-iron. The
space between the front of the boilers and the wheels is used for the firing-rooms, the coal, and the
blowers with their driving engines.
The fuel used is the anthracite coal, and the consumption in both boilers is about 6000 pounds per
hour. The durability of the boilers depends very much on the care which is taken of them.
The Fire-bars are 11 inch wide on the top, with
a space of 7 of an inch between them; they are
cast in pairs, and have a circular groove along
their upper surfaces, which, becoming filled with
ashes, &c., protects the bar from the extreme heat
1508.
1509.
of the fire.
Fig. 1508 is a section of fire-bars of the Georgia
and Ohio, burning anthracite coal. Total grate
surface, 416 square feet; steam, 15 pounds per square inch; consumption, 5000 pounds weight per hour
in the four boilers.
Fig. 1509 is a section of fire-bars of the New World, burning anthracite coal. Total grate surface,
221 square feet; steam, 20 to 35 pounds; consumption of coal per hour, average 6000 pounds.
The Blowers are of the direct-action kind, that is, are worked directly on the shafts of their engines,
and they are consequently of much larger diameter than those whose speed is got up by pulleys and
belts. They are made precisely in the same manner as a paddle-wheel, having cast-iron centres, wrought-
iron arms, and wooden buckets, all of course of very slender proportions, answerable to the nature of the
work they perform. The casing of the blowers is made of wood, and the air passes through wooden
conduits under the fire-room floors, to the ash-pits, which are furnished with suitable doors of wrought-iron.
The Blower engines, of which there is one to each boiler, have 14-inch cylinders, by 14 inches length
of stroke; they are very simple and compact direct-action engines, and are bolted to perpendicular
posts which are fixed to the deck; they receive their steam from the boilers, and exhaust into the con-
denser, by which the benefit of the vacuum is obtained. The handles of the steam regulators are
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placed within convenient reach of the firemen, who can thus start or stop the blower engines, increase
or diminish their speed at pleasure, and to suit the varying requirements of the fires.
The Safety-valves are of the usual description, with levers and weights; they are eight inches in
diameter, and there is one to each boiler.
The Pipes round the engine, both steam and feed, are of wrought copper, with cast flanges.
The dimensions of the New World are,
Ft.
In
Ft. In.
Length
375
0
Breadth
36 0
Breadth over guards
69 0 Depth of hold
10
6
She is constructed of wood. There are some good examples of iron boats, two or three of them of
considerable size. The external planking is 8 inches in thickness, and the ribe are sheathed internally,
for a considerable distance amidships, by double-crossed diagonal planking. Further forward and aft,
the sheathing is single, and towards the ends of the boat the ribs are not sheathed. The floor timbers
are strengthened by several longitudinal timbers or keelsons of considerable size. To compensate for
the want of depth in the sides of the boat, the 'hog-back" or bow" frame, is applied to strengthen it.
This consists of timbers joined together in the shape of a bow, springing from the side at some little
distance from each end of the boat, and rising to a height of 20 or 25 feet at the centre. It is braced
to the side in several places by vertical and diagonal timbers and bolts. The whole forms a powerful
trussed framework, which is placed directly over the side of the boat, and is to be regarded as being
virtually an addition to the depth of the side. The floor of the boat is strengthened by a system of
bracing, consisting of masts 40 or 50 feet in length, which are slipped on the keelson, and are furnished
at their top with caps, to which are fastened iron rods: these rods radiate to the sides of the boat, like
the shrouds in a ship, and they thus transfer the upward pressure on the centre of the floor directly to
the side. The deck beams project over the sides of the boat to the extreme width of the wheel-houses,
forming what are called the guards." These guards are sup-
1510.
ported by diagonal struts underneath them, and they overhang
at the centre 16 feet 6 inches; they meet in a point at the bow,
and at the stern project about 2 feet 6 inches, forming a gang-
way round the ladies' saloon. The New World being a day
boat, has of course no sleeping berths. The entire space below
deck, with the exception of that occupied by the engine, is de-
voted to two immense dining-saloons. On the after-part of the
main deck is the ladies' saloon, nearly one-fourth of the length
of the boat. Over this is the hurricane deck, which extends
nearly to the bow, and forms a magnificent promenade. The
space underneath this deck, forward of the ladies' saloon, is
appropriated to the baggage, &c., and on each side of it are
rooms for the accommodation of the officers and crew of the
boat. The fittings and decorations of the saloons are most
costly and magnificent. The night boats have three tiers of
berths running completely round the saloon under the main
deck, and there is another saloon upon the hurricane deck, ex-
tending entirely over it. Opening into this saloon, and on each
side of it, are state-rooms containing berths. These night boats
thus possess sleeping accommodation for many hundred pas-
sengers. The passage from New York to Albany occupies on
the average about 9 hours: the total distance is 146 miles.
The boats usually make 13 landings, which involve a loss of
time of at least 5 minutes each, leaving 7 hours 55 minutes as
the average running time, giving a speed of about 181 miles
per hour: this is, however, by no means the top speed, since
the passage through is frequently made in much less time.
Upwards of 20 miles per hour is commonly effected, and when racing, the swifter boats have occasionally
moved at the tremendous rate of at least 22 miles per hour through the water.
Details of the engine of the Osceola.-As another example of American steamboat engines, we have
selected the engine of the steamboat Osceola, made by Adam Hall, of New York, and represented in
Figs. 1511 to 1534. The frame is made of yellow pine, well jointed and bolted together, the mortises
and tenons being well inlaid with white-lead. The timbers which sustain the crank-shaft bearings are
firmly dowelled and bolted to the fore-leg of the main frame, and are further supported with large
knees of oak, firmly secured to the keelson. The prevailing and American characteristic in the construe-
tion of the engine consists in the free use of tension-rods and straps of wrought-iron, arranged diago-
nally so as to receive and sustain the alternate strains to which the moving parts are subjected. The
advantage of this principle of construction is very obvious, as it renders the parts extremely strong and
rigid, at comparatively a small expense of material. This will appear from the description which fol-
lows. The arrangement of the working parts is simple and efficient: the handles for starting, stopping,
and the injection, being brought to one spot behind the cylinder, thus enabling the engineer to attend
instantly when required. The arrangement by which the eccentric-rod is supported on a vibrating rod,
renders the working of the engine much less laborious than without it and by using the balance-valves in-
stead of the ordinary poppet-valves, a very moderate degree of manual force is requisite to work the engine.
Fig. 1511 is a side elevation of the engine. Fig. 1512 is an end elevation, exhibiting the steam-chests,
the cylinder, and the parallel motion. Fig. 1518 is a vertical section of the steam cylinder, the condenser,
the bed-plate, and the air-pumps. Fig. 1515 is a plan of the bed-plate, showing the passage connecting
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ENGINE, VARIETIES OF THE STEAM.
the condenser with the air-pump, and the opening by which the foot-valve is introduced to its place. Fig-
1516 is a transverse section of the steam-chests, showing the arrangement of the balance-valves. Fig.
1517 is a plan of the steam-chest, and of the cylinder with the lid removed. Figs. 1518 and 1519 are
views of the traverse shaft for working the valve-lifters. Figs. 1520 and 1521 are face and edge views
of the crank, showing the method of binding it by a wrought-iron strap. Figs. 1522 and 1523 are front
and side views of the connecting-rod, with the method of bracing it by wrought-iron rods. Figs. 1524,
1525, 1526, and 1527, are elevations and plans of the crank-shaft and main centre pedestals, showing
the attachments for securing the blocks to the framing. Figs. 1528 and 1529 are an elevation and a
plan of one of the paddle-wheels of the steamboat North America. We give this wheel as an example
of American paddle-wheels, and of the modes of framing timber for the support of the journals of the
paddle-shafts. Fig. 1530 is a front view of one of the floats; Fig. 1531 is an edge view and Fig. 1532
is a plan. Figs. 1533 and 1534 are a face and edge view of one of the centres of the wheel
1511.
F
K
x
y
E
0
G
2
E
b
h
A
D
A
C
1
b
X
d
a
'II
9
C
r
D
a
M
M
L
o
c
K
c
LE
B
SCALE.-1 inch=1 foot.
The following are the literal references :-
A. is the principal frame, which supports the main centres of the beam, and also the bearings of the
crank-shaft.
B, are the keelsons.
a a, the fore and aft legs of the frame.
b, the upright post under the main centre.
c, oak knees, by which the legs are secured to the keelsons.
d, timbers which support the crank-shaft bearings; the fore and aft timbers are placed obliquely to
strengthen the support.
e, the back-stay for further securing the main centre.
C is the steam cylinder, and C' is the cylinder bottom.
f. the piston; the under side of it, 1, is a solid web, rounded and in one piece with the centre, 2, by
which it is keyed to the rod, and with the circular flange, 3, at the circumference, upon which the pack-
ing is laid. These three parts are connected together by stiffening flanges, 4; and the whole is covered
in by a flat plate, 5, which holds down the packing, and is bolted to the body of the piston.
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ENGINE, VARIETIES OF THE STEAM.
575
g, the piston-rod.
hh, the steam ports; the under port is formed in the cylinder bottom. This, it will be observed, is
hollowed out to the form of the under side of the piston.
i, the clutch and cross-head, keyed to the upper end of the piston-rod.
k, the links connecting the cross-head to the working-beam.
D, are the steam chambers, in which are placed the valves for regulating the motion of the steam
into and out of the cylinder.
11, the chambers whence the steam is admitted to the cylinder.
m m, the chambers into which the steam is discharged from the
cylinder.
I
nn, pipes connecting the upper and under chambers; bolted fast to
upper chambers, but connected to the under chambers by expansion
joints.
v
h
o, the steam-valves, and p, the exhaust-valves, fixed in pairs on the
spindles, and denominated equilibrium or balance valves.
5
qr, the valve-spindles, having their under ends guided in inverted
caps, introduced through the under sides of the steam-chests; their
upper ends pass through stuffing-boxes, and are connected on the out-
f
side to the brackets on the lifting-roda.
1514.
1512.
q
P
i
r
h,
t
L
II
K
1513.
n
ml
D
N
me
1515.
N
K
k
A
K
N
B
B
m
SCALE.-11 inch=1 foot.
s, the steam-pipe from the boiler. It is furnished with two valves; one of them c", is the throttle
valve; the other d", is the cut-off valve; the latter is worked by a cam fixed on the crank-shaft, which
works the lever e", the fulcrum of which is fixed on the timbers of the crank-shaft bearings; this lever
working the lever on the valve-spindle by means of the rod f", the traverse-shaft and levers g", and
the rod h".
t, the exhaust-passage, connected to the passage i', in the condenser.
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576
ENGINE, VARIETIES OF THE STEAM.
1516.
8
-
r
q
P
0
P
u
и
b
0
m
6
b
1523.
1522.
G
n
n
r
q
THE
P
0
m
l
P
u
0
b
t
8
1517.
C
1521.
1590
h
D
H
H
WALKOU
S
[2] 1518.
a
d
2
1519.
3
'26
,
12
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ENGINE, VARIETIES OF THE STEAM.
577
uu, the steam passages to the cylinder.
v, the lifting-rods, with brackets, 1, 1, 2, 2, fixed on them, and connected at the extremities to the
valve-spindles, on which they are adjusted by nuts; 3 3, the lifting faces.
w, the traverse-shaft; 1, the lifting-frame 2, the lifters 3, the eccentric-rod lever. (See Figs. 1518
and 1519.)
We may take this opportunity of describing the operation of the balance-valves, and of pointing out
the peculiar advantages of them. Referring to Fig. 1516, it will be observed that the valves are ar-
ranged in pairs, keyed on distinct spindles, and that each pair, therefore, is moved as one valve; fur-
ther, the valves in each pair are of unequal diameters, the upper valves o, on the steam-side, being
larger than the under valves, and, on the contrary, the under-valves p, on the exhanst-side, larger than
the upper ones. And here the peculiar and elegant adjustment is shown. The common poppet-valve
sustains the full pressure of the steam on its exterior surface, which must, therefore, be overcome before
the valve can be opened; but, in the balance-valve the steam pressure is made to balance itself, (hence
the name,) as it enters the steam port from both above and below. The upper valve in each pair on
the steam side is larger than the under by as much as will afford, by the difference of pressures upon
them, sufficient force, in conjunction with the weight of the valves, to shut them steam-tight in their
seats. Vice versa, the under valve in each pair on the exhaust side is the larger of the two; that by
the resulting tendency of the pressure of the steam from within, when entering the cylinder through the
steam-valve, the exhaust-valve may be kept shut when required.
Thus, it is clear that by regulating the relative diameters of the
1524.
valves in each pair, the absolute difference of the areas of surface
of each, exposed to the steam pressure, may also be regulated;
and, consequently, also the amount of pressure effective in shutting
them. In the present instance, the valves are 10 inches and 9
g
inches respectively in diameter; therefore, the steam pressure
effectively exerted in shutting them is that due to a surface equal
to the difference of these areas, or to 15-2 square inches. Let the
steam pressure be 50 lbs. on the inch, then the acting pressure will
1525.
3
amount to 15.2 X 50 = 760 lbe, or, the weight of the valves being
added, say 840 lbs. This will, indeed, appear little when it is
considered what a common poppet-valve would require. If the
poppet-valve were 11 inches in diameter, it would be subject to a
1596.
pressure of 4750 lbs. The slides, also, such as are used in British
engines, weigh 3920 lbs, without the friction of the faces being
taken into account. But, in fact, as the starting lever has a power
of 6 to 1, the resistance to be overcome by the engineer in starting
is only 140 lbs.
1527.
E are the parallel guides for the cross-head of the piston-rod.
These, the cross-head, and the links k, constitute the parallel motion
of the engine. The guides E are bolted to the projections on the cylinder flange, seen in Fig. 1517,
and are stayed to the frame A, by wrought-iron ties, and a small cast-iron cornice near the top. See
Fig. 1511.
F is the main lever of the engine.
x, a cast-iron centre, strung with tension-rods.
y, tension-rods of wrought-iron, which are strapped to the centre piece at the middle, the extremities,
and the intermediate points.
2, additional tension-rods, strengthening the intermediate points where the air-pump and force-pump
rods are connected.
The main centre pedestals are represented in elevation and plan in Figs. 1526 and 1527. 1, the
sole; 222, flanges for securing the bearings more steadily to the frame.
G, the connecting-rod constructed of wrought-iron.
a', the rod, fitted with straps at the ends for embracing the bushes.
b'b', tension-rods for stiffening the main rod, and preventing the effects of vibration. These rods are
jointed at the upper ends to the main rod; held in tension at the middle by the strut c', which is
screwed and nutted at the extremities to regulate the tension of the rod; and keyed up at the under
ends.
H is the crank, composed of a cast-iron body, and a wrought-iron binding strap.
d', the cast-iron centre, in which the holes are formed for receiving the ends of the crank-shaft and the
crank-pin. Its form in section is that of a web terminated on both sides by flanges.
e', a wrought-iron tension-rod in one piece, passing entirely round the crank.
f', horns cast upon the crank for the purpose of stretching the strap e', the strength being thereby
rendered available.
The fellow of this crank, which is seen in the general elevation, Fig. 1511, is differently formed, being
made solid at the end, and provided with bolt holes, through which a strap embracing the crank-pin is
introduced and screwed upon the other side. By this arrangement, the crank-pin may at any time be
readily disengaged from the crank, and the parts are more easily put together.
I is the crank-shaft.
g', the plummer-block. 1, the sole of the block resting on the timbers: 22, flanges for securing the
block to the framing by bolts and nuts; 33, snugs cast on the sides of the sole, through which holding-
down bolts are passed, which are secured to the keelsons.
a", the eccentric for working the balance-valves.
6", the eccentric-rod, having its length divided, at a point near the handle, into two parts jointed
together, the longer and heavier part next the eccentric being supported on a vibrating joint. By this
73
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578
ENGINE, VARIETIES OF THE STEAM.
means it becomes an easy matter to disengage the rod from the lever of the traverse-shaft; which is
done by means of a small rope attached to the extremity of the rod.
K is the condenser.
i', the exhaust-steam passage.
k', the injection passages.
l', the injection cocks.
m' m', the flanges by which the condenser is bolted to the principal frame.
L is the air-pump.
re', the bucket, the construction of which is obvious from the section, Fig. 1518.
o', the bucket-rod.
1528.
I
K
K
M
E
M
C
A
A
B
B
p', the delivery valve, which is cast hollow, and has its lower edges, where it rests on the air-pump,
filed true, so as to fit and form a good joint. This serves a two-fold purpose, namely, as the air-pump
lid and the delivery valve. Its action is simple and ingenious; for when the bucket arrives at a certain
height, the lid is raised and the water flows out all round, thus discharging more effectually and rapidly
than by the common valve, and requiring little or no power to discharge, having only the lids to raise.
q', the hot-well, made of copper, and riveted to the air-pump by means of a vertical flange.
r', the waste-pipe.
1529.
s', the feed-pipe.
t', the pipe for drawing off the water from
the hot-well.
u', the rod from the beam, which drives the
air-pump rod.
Q
v, the guide for the cross-head of the air-
pump rod, staid to the principal frame by
means of the bracket w'.
M is the force-pump.
x', the pump-rod, moving in the guides y' y',
driven from the beam by the rod x'.
M' is the bilge-pump.
N is the bed-plate.
i", the foot-valve.
The principal dimensions of the Osceola are these:-
Diameter of cylinder
31 inches.
Length of stroke
11 feet
Length of beam
17
44
9 "
Length of connecting-rod
21
44
1
66
Lengths of links
7
"
6
"
Height of beam, from keelson
31
"
0 "
Width between guides of piston-rod
3
"
вь "
Diameter of paddle-wheel
28 " 0 $6
Number of strokes per minute
24
Velocity of piston in feet per minute
528
The paddle-wheel, of which we have represented the construction in Figs. 1528-1529, is the wheel,
30 feet in diameter, of the steamboat North America.
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ENGINE, VARIETIES OF THE STEAM.
579
Fig. 1528 shows the outside framing of the paddle-box, or, as it is frequently termed, the wheel-
house; also an elevation of the paddle-wheel, showing the arrangement of the buckets, arms, centre-
plate, dtc. ; A A is the main waling which rests upon the transverse timbers B B, which project from the
side of the vessel. C, the main upright on which the outer bearing of the paddle-shaft E rests; DD,
diagonal framing for rendering the upright C steady, and also for completing the truss formed by the
four pieces. G G, two lighter diagonals quartered into FF, which are mortised into A A, and firmly
bolted together with I; the foot of I is mortised into H, which acts as a tie to confine the pieces F F to
their places, thus forming a stiff framework for the planking of the wheel-house, and supporting the
outer end of the shaft.
K K K are the arms; LL, battens by which the floats are attached to the arms; MM, the float
boards; N an inner ring of segments of wood for the purpose of staying the arms; 0, an outer ring of
iron for further security; P, the centre-plate.
Fig. 1529 is a plan of the paddle-wheel, showing the arrangement of the floats, which gives this kind
of wheel the name of split bucket," and also showing the diagonal bracing QQ, for the purpose of pre-
venting vibration in the wheel.
1531.
1534.
U
o
1530.
L
L
M
1533.
L
M
TT
A
N
1532.
D
Fig. 1530 is an enlarged view of one of the floats, showing the method of fastening the same to the
arm. K K are the arms, three inches by six deep, of red pine; LL, two battens of hard wood placed
on the face of the float to retain it more firmly against the arm when the motion is reversed, above 57
inches wide at one end, and 4 inches at the other, and one inch thick; the float-board M, is 5 feet 8
inches long, 2 feet 4 inches wide, and 11 inch thick; it is fixed to the arms K K, by means of straps
passing round the arm, through the batten L and washer R. and held to its place by A screws and nuts,
as shown in Figs. 1513 and 1515; it is also held by two inch bolts and nuts at TT.
Fig. 1531, a side view of the method of attaching the same.
Fig. 1532 shows the method of connecting the outer ring to the arms; aaa is a strap of iron, half
an inch thick and three inches wide, which goes round the arm K, and by being riveted tight to the
rings 00, keeps the arm steady in its place.
Fig. 1533 is an elevation of part of the centre-plate, showing the arrangement for fixing the arms.
A aa is a plate with webs cast upon it, 16 in number, and at B they diverge to the periphery of the
plate, thus forming 16 spaces 6 inches wide, and 16 smaller ones. In the wider spaces, holes are
drilled or cast for receiving the t bolts, which are used in fixing the arms to the plate. D is the hole in
the centre, 14 inches diameter, by which the wheel is fixed to the shaft; C is the ring which is made 2
inches thick and 71 wide, for the key-seats. The plate A is one inch thick, as are also the webs BB.
Fig. 1534 shows the thickness of the plate and the width of the boss or ring C.
Pistons.-By presenting a somewhat heterogeneous and unselected enumeration of the principal
varieties, just as they have occurred to us in practice, and noting their respective characteristics, whether
merits or defects, we may, perhaps, make our account more instructive than if we were to give either a
more methodical description or more restricted catalogue.
A consideration of the annexed sketches leads us to rank metallic packed pistons under two divisions,
(which, if not perfectly distinct, are sufficiently so for the purpose of classification,) to one or other of
which each may be referred those in which the expansive force of the rings alone is used, and those in
which it is either assisted or entirely superseded by springs. Of the former kind, we may reckon three
varieties; first, those in which hemp packing requires to be compressed into the space between the
rings and the piston, to aid the elasticity of the former; this is commonly the case in pumping engines,
where hitherto the more complicated and expensive descriptions of packing have not been generally
adopted.
Fig. 1585 represents a piston of this variety; the oblique cut in the ring being designed to prevent
the sharp edges of the break from grooving the cylinder. In this description of piston, two rings are
generally employed, one above the other, with the breaks about 90° apart, to prevent the steam
escaping at the joint. This is the simplest kind of metallic packing, but when properly fitted up, it
possesses nearly all the advantages of the more complicated descriptions; the only disadvantage being
the necessity of occasional adjustment, when the internal hemp gasket loses its elasticity, the frequency
of which depends upon the accuracy with which the end joinings of the external rings are contrived to
prevent the inlet of steam into the hemp, and also in some degree upon the temperature and pressure
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ENGINE, VARIETIES OF THE STEAM.
of the steam itself. Another form consists of a single ring with a tongue joint, as shown in the
figure.
Closely allied to the above is what we may term the second variety of this species, an external
packing ring like the former, but deriving its tightness from its own elasticity, and, of course, not
dependent on the hempen packing behind. The simplest and perhaps the most common method of
giving the requisite spring is to turn the packing rings a little larger
1535.
than the diameter of the cylinder, and when sawn through to cut a
tenon and mortise, or a half check in the abutting ends, and then to
compress the ring by an iron hoop with screws, and to fix it tempo-
rarily with a pin put through the overlapping or mortised ends; in
this state the rings are ground on the surface joints, and the piston
made ready for its place; when, the hoop being unscrewed and the
temporary pin withdrawn, the rings are suffered to expand in the
cylinder by their own elasticity, which will generally continue to act
till the rings and the cylinder are 80 much worn as to permit the
rings to expand to their natural extent.
Sometimes the abutting ends are left plain, in which case a piece is
merely cut off one end, to allow the ring to be compressed to a lesser
diameter. Great diversity of opinion exists as to the merit of this
species of packing: that it is a decided improvement upon the former
is unquestionable, but it is alleged, that in accuracy of form, and
facility of application to the cylinder, it is greatly inferior to the
ordinary more complex varieties, with a number of segments and
artificial springs to each. It is said, in the first place, that it tends to
wear the cylinder off the truth. Appeal to experience might seem
the shortest way of settling the question, as many pistons both of
the simple and the amended construction are in use, but in this, as
in many other cases, recorded experience only serves to prevent
any conclusion whatever, or rather tends equally to two contradictory
results.
Let us then investigate the action of the simplest form. The ring,
SCALE.-1 inch=1 foot.
when first compressed, does not naturally assume the circular form, as by the two ends being brought
together the tendency to expand to its original dimensions is mainly checked in only one direction.
When confined in the cylinder, however, it will be seen at once that it is compressed equally in all
directions, and must therefore exert a corresponding force equally in every direction, to recover its
original dimensions. This appears 80 plain, as scarcely to be susceptible of illustration.
The variety, ingenuity, and complexity of the various contrivances adopted, to correct this supposed
defect in this description of packing, and the alleged success by which they have been attended, must
be our apology for dwelling on the subject. But although the apprehended evil did exist in its full
amount, and the rings really had a greater tendency to expand in the direction perpendicular to the
diameter passing through the break, we do not see what bad effect would ensue; the cylinder would be
worn almost imperceptibly oval, till at length the inequality of pressure in the ring would be exactly
counterbalanced by corresponding ellipticity in the cylinder; and not only so, but the next rings that
happened to be put in would fit with as great truth as the most hair-breadth system of compensation
could possibly effect, since the alleged unequal expansion of the ring would then correspond exactly
with the shape to which the cylinder has by that time worn.
It is abundantly obvious, however, that the effect upon the cylinder of the unequal expansion might
be altogether neutralized, (were it ascertained to have any proper existence,) by using two rings instead
of one, the position of the joints being 90° apart. It is not uncommon to have the rings placed with
the joints on opposite sides of the cylinder, or 180° apart: an arrangement only useful to prevent the
passage of the steam through the single break, (an object which might be easier attained in another
way,) and incapable of exerting a correcting influence on the above-named inequality.
Under the third modification of this description of packing, we class pistons in which each ring is still
in one piece, but in which some of the above modes of compensation are had recourse to. The common
method is, simply to turn the ring about one-third thinner towards the part where the joining is made;
two rings are commonly used, the position of the joints being as above described, and instead of the
rings being turned of greater than the required diameter, and then sprung in, the requisite elasticity is
given by hammering the thicker semicircumference on the hollow side. Of course, the same method
may be taken with rings of uniform thickness, and to derive the full effect of the hammering, it might
be well to retain the original skin of the casting on the inside of the ring. The advantage of giving the
requisite elasticity by hammering rather than by compressing the ring, lies in the more perfect circu-
larity ensured by the former; but were the precaution taken to turn up the compressed rings in the
lathe, this difference would no longer have place; and this is now generally done in addition to the
hammering.
This arrangement has been generally found to work very well; but perhaps not better than the pre-
ceding more simple variety, when the workmanship of both is equally correct. Numberless methods
have been taken to prevent the escape of the steam by the open end joints which this species of ring
exposes; frequently hemp packing is put behind the rings; sometimes they are merely cut without any
further provision; but by far the best plan, is to rivet a piece of brass or iron, previously fitted to the
proper curvature, to the inside of the ring on one side of the break, 80 that it shall apply correctly to the
other side, and alide along steam-tight as the ring expands by wearing. Inattention to this simple pre-
caution has been the occasion of great inconvenience, and has even led to the substitution of a much
more expensive, though not in reality much more efficient system.
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ENGINE, VARIETIES OF THE STEAM.
581
The second principal division of our subject comprises many subvarieties: we mean that class of
pistons where artificial springs are used, acting in most cases by the intervention of blocks or wedges.
The most common construction is as follows :-Two strong cast-iron rings of such dimensions as to have
no perceptible elasticity themselves, (say from 14 inch to 21 inches square in the cross-section,) are cut,
each into from three to six or eight segments, according to the size of cylinder, or other regulating cir-
cumstance, placed the one above the other, 80 as to break bond at each joint, and at each break part of
the ring is cut away to admit the introduction of a wedge usually of the angle of 90°, the point of which
may be 1 inch from the surface of cylinder a common elliptical spring is then introduced between the
body of the piston and the back of the wedge. Sometimes, instead of a wedge, a simple block is used,
or the spring presses immediately upon the back of the ring.
In the original form of this piston the points of the wedge came in contact with the cylinder, being
situated in the periphery of the piston, and. in order to prevent their injurious action in grooving the
cylinder, it was proposed to make them of softer metal. In this description of piston, the mode of action
of the wedges is what seems principally to require investigation. When the points of the wedges are
not in contact with the cylinder, the mode of action is sufficiently obvious; the intervention of the wedge
serving simply to multiply the energy of the springs on the principle of the wedge, as a simple mechanical
power. Of course, the more acute the angle of the wedge, the greater force is imparted to the springs,
on the principle of virtual velocities; and were the segments only required to expand indefinitely, instead
of expanding and contracting by turns, to suit the inequalities in the cylinder, then a very acute wedge
might be used; but as the wedge must be ready to spring back, to allow the packing to yield when
it comes to a tight part of the cylinder, as at the top and bottom of the stroke, it is plain that the incli-
nation must be considerably greater than the angle of repose; it is seldom, however, made less than 80°
or 90°, but we believe a considerably sharper angle would be found to answer. Considering now, for a
moment, the case in which the points of the wedges come in contact with the cylinder, it might seem, at
first sight, that they would exert no pressure at all upon the adjacent segments; and such would be the
case, were it possible for them to wear no faster than the rings themselves; a little consideration, how-
ever, will show that this can never be the case, as the wear upon the wedge must be to that of the ring,
in the proportion of the side to half the base of the wedge; that is, in the case of a right-angled wedge,
as the diagonal to one of the sides of a square: were the wedge and cylinder then to be made of the
same material, the wear of the cylinder opposite the wedge would exceed that of the rest of its surface,
in the above proportion, or probably in a somewhat higher ratio, arising from the different grain of the
metal composing the wedge. The wedges, however, are almost always made of gun-metal, which
serves in a great measure to neutralize what would be otherwise the injurious tendency of this
arrangement.
Fig. 1536 represents two views of the locomotive piston. The peculiarity of construction and mode
of action is apparent from inspecting the drawing. By fitting a tongue-piece, or tenon, into a corre-
sponding mortise, in both wedge and ring, it is intended to prevent the passage of steam at the breaks
of the segment, instead of the common method of using two rings, each of half the thickness, with the
joinings of the one ring placed midway between those of the other. We believe this construction has
been found to answer perfectly; but this is not paying it a distinguishing compliment, as we shall soon
see that the same may be said of certain other descriptions, about which there is not above one-fourth
of the workmanship here displayed.
1536.
1538.
1539.
1537.
o
ECALE.-1 inch=1 foot.
Fig. 1537 represents plan and section of a piston, differing from the above in having only one wedge
and break in the ring instead of four. The set screw, on the side farthest from the wedge, might be
omitted; the two side-screws serve in some measure to compensate for the sluggish action of the right-
angled wedge. which seems rather to press the ring against the cylinder at the point immediately adja-
cent than to force it open, and thus make it bear equally all round. A more acute wedge would
propagate the pressure of the spring more readily throughout the entire circumference. A circular
spring, like that used here, while it possesses several conveniences, is yet less delicate and perfect in its
action than the common elliptical kind; and perhaps, too, less easily reset or retempered.
Very similar to the first variety is that shown in Fig. 1538. We doubt whether the slight superiority
in point of simplicity gained by doing away with the adjusting screws, and substituting a single spring
hoop, be not more than counterbalanced by less perfect action. A method intermediate between the
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ENGINE, VARIETIES OF THE STEAM.
two last is sometimes adopted; the packing-ring is cut, and a sliding piece and wedge employed in two
opposite places, and a circular spring, with set screws, acts upon each.
Fig. 1539 represents a plan of the piston. The distinctive feature in it is, that each spring acts upon
one wedge in the upper ring, and another in the lower, the centre of the spring, contrary to common
usage, being made the " point d'appui," from the body of the piston.
Fig. 1540 represents a piston that has been much used. It consists of three concentric rings, the two
outer being rebated and mortised upon their edges, and together filling up the space between the flanges
of the piston. The inner ring is equal in depth to the two outside rings. When the rings are turned to
fit the cylinder and each other, they are hammered on the inside, to give them a tendency to spring
outwards, and are then cut through, to allow them to expand. The divisions of the rings are placed 80
as to break joint. To provide for the wear of the outside rings, springs are placed at the back, which
can be tightened up by means of screws bearing upon the centre part of the springs.
1542.
1540.
1541.
SCALE.-1 inch=1 foot.
Fig. 1541 represents a kind of piston very similar to Fig. 1537. The pistons are sometimes made of
brass. This is an advantage in horizontal or inclined cylinders, as the softness of the material, and the
greater lightness of the piston, considerably reduce the wear of the cylinder. Brass pistons have been,
on this account, much used for locomotive engines ; one drawback, however, to their employment, is,
the inferior elasticity of the metal, which renders the employment of artificial springs necessary.
Fig. 1542 represent+ the packing-rings. The peculiarity of this piston consists in the two rings being
grooved and tongued into each other in a manner similar to common flooring-deals.
Fig. 1543 represents the plan of a piston which is superior in simplicity, and at least equal in effi-
ciency, to several of those we have figured.
Fig. 1544 represents the piston which is free from all or most of the defects we have pointed out, and
has given much satisfaction in practice. The position of the rings, in being placed with the breaks, 90°
apart instead of 180°, is one of those trivial but judicious arrangements which often determines the
character of a mechanical contrivance.
1545.
1543.
1544.
BCALK.-1 meh=1 look.
SCALE inch=1 foot.
Fig. 1545 is a plan and section of piston much used. It has two packing-rings, 1 inch X 11 inches,
each in three segments, pressed out by three elliptical springs with set screws, through the medium of
an inner ring equal in depth to the two, and cut in three places.
These then are the principal specimens of locomotive pistons: we shall next describe some of the
most approved pistons for marine engines, all of which are also applicable to land engines.
Fig. 1546 represents a variety of packing adapted for marine engines.
Fig. 1547 represents Jessop's spiral metallic packing. On considering the action of the spiral coils,
when the ring is compressed into a lesser diameter, it will be found that the tension of the springs is a
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ENGINE, VARIETIES OF THE STEAM.
583
minimum at the centre of the coil; while it increases towards each extremity in the ratio of half the
number of coils to unity.
Fig. 1548 represents an arrangement that was formerly extensively adopted. The packing consists of
four rings, from t to 11 square, according to the size of the cylinder, which may vary from 6 to 50 inches
in diameter. In pistons of the latter dimensions the rings are turned fully two inches more in diameter,
and afterwards cut in one place, and bent to the proper circle in a mould prepared for the purpose-
the ends being half checked in such a way as to be steam-tight without the necessity of using packing
behind, which, however, is frequently added. In order to bring the cylindrical surface of the rings
sooner to an exact bearing, a groove is turned out of the outer circumference of each: this may help,
besides, to keep the piston tight, by affording a lodgment for oil and tallow, and may in certain circum-
stances be of considerable use. In one instance within our knowledge this kind of piston has been at
work, with occasional interruption, but little or no repair, for a period of ten years.
1548.
1546.
1547.
SCALE-1 Inch=1 foot.
Fig. 1549 represents plan and section of piston both for marine and land. This may be regarded as
a favorable, and at the same time, characteristic specimen of the most generally approved and widely
adopted variety of packing in which separate springs are employed. The ease with which the springs
may be bent and reset to the proper compass prevents set screws from being required the only seri-
ously objectionable point seems to be the expense of fitting and grinding steam-tight the ten wedges
required. The use of wrought-iron nuts, fitted into the body of the piston to receive the junk ring
screws, instead of tapping them into the cast-iron, is a very obvious improvement.
1549.
1550.
SCALE.-1 inch=1 foot.
SOALE.-1 inch=1 foot.
Fig. 1550 represents a form of marine piston. To enter into a detailed analysis of it would be super-
fluous, after having considered 80 much at length the general principles by which our judgment has
been regulated.
Fig. 1551 is another form of piston. The peculiar shape of the blocks against which the springs press,
instead of the usual V wedge, is one point of identity.
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ENGINE, VARIETIES OF THE STEAM.
Fig. 1552 represents the form of piston much used.
1551.
Two rings, about 24 inches square, (cylinder being 65
inches diameter,) divided into two segments, the lengths
of which may be in the proportion of 1 to 5, each ring
being pressed out with a number of springs, generally
made very stiff, and of little compass: the rings, in con-
sequence, wear 80 rapidly, that we have known them to
require to be eked with a considerable thickness of
copper at the ends. The distinguishing feature of this
piston lies in the cut on the outer circumference of the
rings being made at a considerable angle with the per-
pendicular, while that on the inner side is vertical; an
arrangement that we do not recollect to have met with
before.
Fig. 1558 represents a species of packing-ring also
much employed. Only one packing-ring is used, about
34 inch X 14 inch; sprung in from a larger diameter, or
hammered internally so as to have considerable elas-
ticity. This ring is cut in only one place, and a piece,
110
8 or 9 inches in length, half the thickness, and about
one-third the depth of the ring, is checked in on the
upper side, in order to break bond; and at the back of
the joint a block is placed, screwed to the one end of
the ring and loose at the other, so as to prevent the
steam from passing through the cut. In addition to the
elasticity of the ring, it is pressed out by six elliptical
SCALE.4- inch=1 foot.
springs. This is, on the whole, one of the best marine
pistons. The ring, however, in wearing, deranges the joint between the ring and the small segment-
piece. The joint opens at each end, 80 that the only contact comes to be at the central point, which is
a defect.
Fig. 1554 shows plan and section of the piston of a cylinder 68 inches diameter. There are two rings
cut into two segments, the lesser being one-third the circumference, with V blocks at the joinings, and
stiff elliptical springs.
1552.
SCALE.-1 inch=1 foot.
Fig. 1555 shows a species of piston. The ring is turned the full size, measuring to the point of the
tongue-piece, and squares are then cut out to allow the ends to come together, 80 that the tongue-piece
is in one piece with the ring. The malleable iron bridle is for the purpose of expanding or contracting
the ring, which is effected by driving in a cutter at the one end of the bridle or the other, whereby the
ring is contracted or expanded. One end of the bridle is attached to the ring by a bolt, which slides in
an oblong hole in the bridle; and if a cutter be driven between the bridle and one end of the piece
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ENGINE, VARIETIES OF THE STEAM.
585
ground on the back of the joint, the ring will be expanded; whereas, if driven at the opposite side, the
ring will be drawn together.
Fig. 1556 represents a marine engine piston. The tongue-piece is not cast in one with the ring, but
is put in with pins; and the slot is on the incline, to prevent a rut in the cylinder. The tongue-pieces,
of this and the preceding variety, are of course ground in, a piece being ground on the back to prevent
the steam from passing. This species of piston ring is probably among the best yet introduced in prac-
tice. It is a very common fault of metallic pistons that the springs are made too weak. We have often
known them to be too weak, but never in any one instance knew them to be too strong.
1553.
1
SCALE.-1 inch=1 foot.
Fig. 1557 represents the piston often used for cylindrical slide-valves. By raising or lowering the
screw, it will be evident that the rings are compressed or expanded. A flat place is of course cast in
the body of the piston to leave room for the bridle.
1554.
SCALE.-1 inch=1 foot.
In the pistons of oscillating engines, it is necessary to take precautions against any compression of the
packing-ring by the weight of the piston during the inclination of the cylinder. The method pursued by
Messrs. Penn is to pack the space between the metallic ring and the piston with hemp. It might be a
good way to force out the ring by means of a V block placed on one side of the piston, in the line of the
74
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586
ENGINE, VARIETIES OF THE STEAM.
trunnion, a steady pin being inserted in the piston on the opposite side, with a corresponding oblong
hole in the packing-ring, 80 as to prevent the packing-ring from turning round at the same time that it
was permitted to expand. Messrs. Penn make use of a single ring and tongue-piece with the block be-
hind recessed, 80 as not to interfere with the hemp packing. The upper side of the ring, too, is sharp-
ened off to an edge.
1556.
SCALE.-1 inch=1 foot.
1557.
1555.
o
SCALE.-1 inch=1 foot.
SCALE.-1 inch=1 foot.
Valves-The function of a valve is to open or close a passage, and all the varieties are divisible into
the genera of lifting and sliding valves. Sliding-valves are generally employed to admit the steam
alternately above and below the pistons of engines, except in the case of pumping engines, and there
1558.
1550.
lifting or spindle valves are usually employed. Safety-valves are
always spindle-valves, though a slide-valve, opened by the rise of a
column of water or mercury, has been proposed as a safety-valve.
The valves of pumps are generally spindle, flap, or ball valves, but
are slide-valves sometimes. A cock is to be regarded as a circular
aliding-valve. The diameter of the spindle of spindle-valves is usually
made about one-eighth of the diameter of the valves; in small valves
the proportion is greater.
Safety-valves.-A common proportion is a circular inch of orifice
per 14-horse power, or 8 of a circular inch per horse power. In ma-
rine engines safety-valves are usually lifted by a lever, which presses
up the spindle from underneath, and the weights are either wholly or
partially hung from the spindle. The spindles are sometimes guided
by means of an iron bar, which passes across the steam-chest; but
this is not a commendable practice, as explosions have occurred from
the jamming of the spindles in the guide, in consequence of an altera-
tion of shape in the steam-chest when the pressure came on.
Fig. 1558 represents the safety-valve of a locomotive engine, which
is of the steelyard kind, and the end of the lever is kept down by a
spring.
Boiler explosions sometimes arise from the adhesion of the safety-valve to its seat, and numerous plans
have been devised, and some of them of considerable ingenuity, for obviating this source of danger.
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ENGINE, VARIETIES OF THE STEAM.
587
The ordinary method of feeding land boilers by a head of water may rank among these contrivances
it is shown in Fig. 1559. A float, which is usually made of stone or iron, is so balanced, by means of a
counterweight, that it rises or falls with the fluctuations of the water level, and in so doing opens or
closes a valve in a small cistern, at the top of a stand-pipe set on top of the boiler, thereby maintaining
the water at the right level. The stand-pipe is of sufficient diameter to receive a float connected with
a chain proceeding to the damper; and as the water is forced up in the stand-pipe to a height corre-
sponding to the elasticity of the steam, the float in the stand-pipe will rise and fall with the varying
pressure, thereby adjusting the vehemence of the draught to the wants of the engine.
If the pressure becomes very high, the water will be forced out of the boiler through
1560.
the feeding-valve. This valve, however, is usually made too small to be capable of
answering as a safety-valve, but it gives intimation of danger. In steam vessels an
upright pipe has been recommended to be applied to the top of the boiler, of sufficient
capacity to give free exit to the steam, and descending beneath the water level, 80 as
to be under ordinary circumstances filled with water. When the steam becomes too
high, the water is forced up this pipe, and proceeds into the chimney by a branch-pipe
provided for the purpose. If the pressure be not speedily relieved, the whole of the
water above the mouth of the pipe will leave the boiler, and then the steam will rush
out. Another plan consists in the application of a vessel at the end of a lever, to
receive the water which flows over from the upright pipe, and this vessel of water is 80
arranged that its weight opens the safety-valve. In some combinations a column of
quicksilver is employed, instead of a column of water; but it has been found that the
quicksilver is gradually dissipated by the action of the steam. A large steam-gage is
recommended by some persons as an effectual safeguard against explosion, in the event
of an adhesion of the safety-valve; but for all ordinary pressures we think the column
of water will be found to be a preferable expedient.
Slide-valves-There are three principal varieties of slide-valves-the long D, the
short D, and the three ported. This last valve, Fig. 1560, consists of a box set over a
central port, and moved alternately over ports set on each side of the central port, 80 as to establish a
communication between the central and side ports alternately. The central port is the escape port:
the steam passes in the direction of the arrows, and when exhaustion is being performed by one port,
steam is being admitted by the other. This
species of valve is used very extensively in
156L
high-pressure engines, and almost universally
in locomotives. It is very simple; and by
leaving the face of the cylinder when the press-
ure within the cylinder exceeds the pressure in
the valve-casing, it enables the water to escape
when the engine primes: but it occasions a con-
siderable waste of steam if the ports and pas-
sages are large; and if they are not large, a
considerable loss of power arises from the extra-
resistance experienced by the piston.
A
The long D valve has always been in much
favor with engineers, though, as we think, with-
out sufficient reason. The short D valve is, in
our judgment, preferable, and we give in Fig.
1561, an excellent specimen of this species of
valve. Some short D valves have only one rod
to connect the ends, and others have two; but
three are preferable, as they give greater stiff-
ness than is otherwise attainable. It is expe-
dient to zinc the connecting-rods, as in the
wake of the ports they frequently get wasted
rapidly away by the steam.
The piston-valve with skewed ports is repre-
sented in Fig. 1562. This species of valve is,
in our judgment, preferable to the D in many
respects. It is more easily worked, admits of
metallic packing, and is not liable to have its
form altered by twisting.
V
In working large engines considerable diffi-
culty is experienced in handling the valves,
from the weight and the pressure of the steam
forcing the valve against the face of the cylin-
der. Various schemes have been adopted to
obviate this disadvantage. In some cases a
small engine has been used to work the valves
at starting, and another plan has been to
balance the valves by the opposing pressure of
the steam. One of these balance valves is rep-
resented in Figs. 1563, 1564, and 1565. It is a
slide-valve, and has no hemp packing as is usual, but is kept tight by means of a metallic packing-ring,
divided into segments which are pressed against the inner side of the valve-chest back by spiral springs
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ENGINE, VARIETIES OF THE STEAM.
and steam pressure. Some inconvenience might be anticipated from the circumstance of the rubbing
surface of the packing-ring at the sides of the valve being greater than at the ends.
aaa is a brass ring divided into segments, as shown in the plan, the object being to allow the ring to
accommodate itself to any slight curve that may be caused by the pressure of steam on the valve-box
back or cover. 6666 is a space containing about three layers of well-plaited square gasket. ccccisa
brass ring in one piece fitted loosely into the groove, having on one side of it a
number of small steel pegs, dddd, on which is placed spiral springs. These
1562.
n
springs force the ring, and by it the hemp packing is pressed hard against the brass
segments, causing them to slide steam-tight against the valve-box cover, the
pressure being further regulated by a communication made between the space in
which the spiral springs work, and the steam in the valve-box.
A communication is made between the condenser and the space within the brass
ring a a a in the valve-box cover, and the condenser regulated by a cock, 80 that
when the engineer is handling the engine he can cause a vacuum at the back of the
slides. EEE is a wrought-iron hoop bound to fit the turned part of the valve,
which slides freely in it, uninfluenced by the valve-rod FF.
The valve employed by Messra. Penn in the most recent of their oscillating-
engines, is substantially the same with that just represented. The ring, however,
is in a single piece, and is tightened against the back plate by means of another
ring, armed with four lugs, lying beneath the packing-ring. Between this ring and
the packing-ring hemp packing is interposed, and the lower ring is raised up by unscrewing, out of
bosses on the valve, four bolts passing through the lugs. These bolts may be unscrewed, and the pack-
ing tightened, by removing four plugs in the back of the valve-casing. By this method of arrangement
1563.
E
Back View.
it is not necessary to make the back of the casing removable, but merely to plane and fit the back to
the rings before the parts are put together. The back plate which forms the cover of the casing is
scraped as carefully as the valve and cylinder faces, but only as much of the back plate is thus fitted as
the ring comes into contact with during the travel of the slide, and the fitted portion is cast a little
higher than the other portions.
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ENGINE, VARIETIES OF THE STEAM.
589
Expansion-valves.-Slide-valves are the most satisfactory species of expansion-valve; but spindle-
valves are the simplest, and they are the most frequently employed. Most of the spindle expansion-
valves are of the double beat or equilibrium kind, such as are used in the Cornish engines. The form of
the cam is a sort of twisted elliptical cylinder, 80 to speak, against the exterior surface of which a
pulley fixed, on the end of a lever, presses, and by the motion thus derived opens the valve.
Fig. 1566 represents the variable expansion-geer of Gonzenbach.
It consists of an ordinary short slide-valve and casing, with ports
in the back, upon which another slide-valve and casing are im-
posed. The ordinary valve is worked in the usual manner; but
1565.
1567.
F
1564.
a
a
E
6
6
W
E
Transverse section.
Perpendicular section.
the travel of the supplementary valve may be lengthened or
shortened, so as to cut off the steam at any part of the stroke. A
is the common valve, and F the valve-chest; B is the supple-
mentary valve, which is a solid block with two perforations, which,
1566.
H
1K
B
F
9
D
2
when opposite the ports in the cover F, admit steam from the supplementary valve-chest K. The
starting-handle is connected with the shaft g, upon which a lever is fixed, and 80 connected by links
with the extremities of the eccentric-rods D and d, that when one eccentric-gab is in geer with the pin e',
upon the valve-lever, the other shall be disengaged. In the figure the engine is in geer for going ahead,
and the reversing eccentric-rod D is disengaged from the ordinary valve, and in geer with the supple-
mentary valve, by means of a second gab f. which receives a pin upon the expansion-valve lever G. in
this lever there is a long slot, in which a pin G, fixed on the valve link H, may be moved to a grenter
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ENGINE, VARIETIES OF THE STEAM.
1569.
:
E
C
H
G
Et
1
I
K
S'
0
B
O
F
H
G
E
Q
L
I
K
S
0
P
c
U
A
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591
or less distance from the centre of the expansion-valve shaft, by means of the handle T; and the
effective length of the valve-lever being thus varied, the travel of the valve receives a corresponding
variation. The expansion-valve thus receives the reversing motion while the slide-valve is receiving the
forward motion.
Fig. 1567 represents the variable expansion geer of Mayer. It consists of an ordinary valve, with
the addition of perforations through the top and bottom faces, each of which is covered by a supple-
mentary valve upon the back of the first, consisting of two solid blocks, into which a valve-rod is
screwed, having a right-handed screw where it penetrates the one block, and a left-handed screw where
it penetrates the other; 80 that the blocks will be set closer or further apart, according to the direction
in which the rod is turned. The ordinary valve receives its motion in the usual way, and the expan-
sion-valve is moved by means of a pin attached to the piston-rod, which works in a slotted lever, to
which the expansion valve-rod is attached. The motion of the two valves is, therefore, at right angles,
and the expansion-valve is about one-fourth of a revolution in advance of the steam-valve. In Fig. 1567,
A is the steam-valve, BB the expansion-valve, TT the valve-rod, with right and left handed screw;
G a wheel attached to the valve-rod, over which a pitch chain passes, by means of which the valve-rod
is turned, and the blocks are altered 80 as to give the requisite amount of expansion; D is the valve-
shaft, and CE the valve-lever; F is the pin attached to the piston-rod. In all cases in which the mo-
tion of the expansion-valve is the same as that of the piston, the slide-valve must be provided with lap.
Sliding cut-off valve.-This is the invention of Mr. Simon P. Winne, of Albany, N. Y. Fig. 1568 is a
vertical longitudinal section of the steam chest and passages of a cylinder, with the valves in their place
and ready to act. ABCD represent a steam cylinder, having on its top A C, the usual hollow steam
channel E E, divided by partitions to separate the entering from the issuing steam in the usual way
with the exit passage G, and openings into the
cylinder at HH. JJJJ is a steam chest made
1568.
a little longer than the ordinary kind, but of the
same form. The steam entering in by the pas-
sage X, fills the chest, from which, as will be no-
ticed, there are four openings into the channels
c
E, and one into the exit passage G. They are
J
J
all properly faced with slides, and arranged in
M
E
E
reference to the valves to move over them, as
seen in the engraving. cd are the three slide-
valves. c and e have solid bottom surfaces, and
d, the central valve, has the usual chambered
D
passage to effect a communication together be-
tween two of the three central passages from
the chest into the steam channel. The valve-
rod K passes through a stuffing-box at the one
end, and has the other end passed through a stuffing-box or into a chamber L. bored out to receive
support and steady its movements. The rod passes through the upper parts of the valves c c, which are
pierced to receive it; but it is not attached, but moves freely through them. The rod K, moved by
the eccentric, communicates motion to the valves by means of two stop-nuts, which screw upon a thread
in the rod for adjusting the cut-off. These nuts will readily be noticed at the ends of the catches.
Upon the two valves c and e are mounted catches h and i, moving on pivots, and have handles k k.
The catch drops down upon the valve-rod and is held in this position by its own weight or a spring, as
may be found most suitable. m is a metallic plate placed over the centre of the valve range. It has
its lower edge curved or made flat, as may be desired. Its chord is parallel with the rod K. This
plate is attached to a spindle at right angles to it, which passes through a stuffing-box, where it is at-
tached to the handle 0, for raising and depressing it, thus attaching and detaching the catches h and i
from the nuts on the rod K. The valve d lies upon its bed unattached to the rod, and is only moved by
the impulse of c and e alternately. Between these two valves and d there is a space to be determined
by the portion of the stroke of the piston at which the steam is to be cut off.
Operation.-The valves are to be attached to the rod by the catches when the cut-off is to be used.
The engine in the engraving is represented as having just begun the stroke of its piston from left to
right, and the valve-rod from right to left. Before the piston has passed over one-third of its stroke, e
will have covered the first opening, cutting off all passage of steam from the chest to the opening H of
the cylinder, and will keep it covered during the remainder of the stroke, during which, valve d is kept
stationary, passing steam from the right passage of the cylinder H, through the two passages indicated
by the middle arrow, and out of G, until the valve e impels it to the left, and the valve c is carried over
the other opening, and opening the other exit passage. This completes the stroke, and the same opera-
tions are repeated continuously from left to right and right to left. When it is desired to give the en-
gine full steam, the lever o is depressed, by which the catches are raised to allow the three valves to
act in concert, operating as a single slide driven by a cam. The stroke can be cut off and regulated by
the handle O. It is only necessary to depress the bar-plate m, to permit the proper catch to drop over
the stop nuts. and the required cut-off will be effected. The valves when used for upright engines may
be kept in their places by springs during the absence of steam pressure.
Expansion-Allen's cut-off-The combination whereby an adjustable cut-off is obtained for engines
using poppet-valves, is represented by the drawings hereto attached, Figa. 1569, 1570.
A is the rock-shaft, B the lifting ro.ls, and c the exhaust-valve lifter, as usually arranged and worked.
D is the steam-valve. E the valve stems. F is a piece attached to the valve stem by means of
which it rests on the toe G. This toe G is attached to the shaft H. On the same shaft H is the toe T,
On the lifting rod B is fastened the stud I, having a centre on which it is supported, and turns one
end of the lever K; the other end L is connected with the arm N, by the rod S. This arm N is at-
Digitized by
Google
592
ENGINE, VARIETIES OF THE STEAM.
1570.
C
G
H
KI
0
N
P
B
B
P
H
G
I
K
I
0
A
P
o
o
Digitized by Google
ENGINES, SUMMARY OF.
593.
tached to the shaft O. On the same shaft 0 is attached the arm P, to which arm is given a recipro-
cating motion coincident with that of the piston, and taken from the beam or any part having the same
motion (suitably reduced) as that of the piston.-On the lever K is placed the movable piece Q, the
roller R is attached to the piece Q, and on the roller R rests the toe T.
It will be seen that by the upward motion of the lifting rod, the end I of the lever K is raised, while
by the downward motion of the arm N the other end of the lever K is lowered. But it will also be per-
ceived that the upward motion of the end I is at its greatest velocity at the beginning of the stroke,
while the arm N, which lowers the end L, has no motion at the immediate beginning of the stroke; by
reason of these relative motions, the lifting end will have the advantage, and the valve will therefore
be raised at the early part of the stroke, but the motion of the lifting end is rapidly diminishing, while
that of the lowering end is increasing; it therefore will soon happen that the lowering end will lower
the valve more rapidly than it is raised at the other end, and thus the valve will be restored to its seat.
The point of stroke at which the valve will be restored to its seat, will depend on the proportion of parts,
and with suitable proportion parts, on the position of the movable piece Q. If, in the position repre-
sented in the drawings, the valve is restored at half stroke, then by moving the piece Q towards the
lifting end the valve will be restored at à later point, and by moving it towards the lower end the valve
will be closed at an earlier point.-Further descriptions of American engines will be found under the
heads, LOCOMOTIVE, MARINE, STATIONARY, and SCREW PROPELLER.
ENGINES, Summary of.-The greater part of this summary is taken from the Engineers' and
Mechanics' Pocket-Book, by C. H. Haswell, engineer in chief of the U.S. Navy.
Nominal Horse-Power of Engine.
Names of Parts.
10
15
20
25
30
40
50
60
70
80
90
100
110
120
Diameter of
in.
in
in.
in.
in.
in.
in.
in.
in.
in.
in.
in.
in.
in.
Cylinder
20
24
27
291
82
36,
40 43
46
48
50
521
551
57
Piston-rod
2
21
24
3
34
31
4
41
41
44
41
5
51
51
Air-pump
12
15
17
17}
18}
21
23
24
26
271
28
30
311
34
Air-pump rod
11
11
2
21
21
21
24
21
3
81
31
34
4
41
Injection-cock
11
11
11
1]
2
21
21
21
3
3b
34
31
31
81
Hot-water pump
21
21
8
31
81
4
41
41
5
51
6
61
7
71
Feed-pipe
11
11
2
21
21
21
21
21
3
3t
31
81
31
4
Steam-pipe
4
5
54
6
61
7
74
81
91
10
101
11
111
12
Waste water-pipe
5
6
7
71
8
9
91
10
10}
111
121
13
131
14
Beam gudgeon
81
44
5
54
of
6
6}
7
71
8
81
9
91
94
Pins in beam ends
2
21
21
8
3₺
31
4
41
41
41
5
51
51
51
Air-pump pins in beam
11
18
11
1]
2
24
21
21
21
2]
3
3f
31
84
Crank pin
21
8
31
31
4
41
5
51
6
6}
7
71
74
8
Main shaft
41
51
64
62
7
73
81
91
10
104
101
111
12
121
Paddle wheels, in feet
9
11
11
12
13
13
15
17
17
19
19
21
21
23
Weigh-shaft bearings
2
21
21
21
25
24
24
21
3
31
34
31
31
34
Stroke of piston
24
30
30
33
36
36
42
48
52
56
60
63
66
72
$4
air-pump bucket
12
15
15
16}
18
18
21
24
26
28
30
311
33
36
44
feed-pump plunger
6
73
71
8
9
9
101
12
13
14
15
16
16}
18
Cylinder cross-head,
Depth of boes
6
73
8
9
91
10,
12
18
14
141
15
16
17
17+
Diameter of boss
4
41
5
51
6
64
73
8
84
9
91
10
11
12
Depth of middle
5
51
64
7
71
81
91
101
111
111
121
13
131
14
Thickness
1f
18
11
2
21
21
21
3
31
31
31
31
4
4d
Air-pump cross-head,
Depth of boss
41
5
51
6,1
64
8
9
10
101
10}
11
111
12
121
Diameter of boss
21
3}
81
4
4g
41
5f
51
54
6
61
64
7+
7+
Depth of middle
31
4
41
5
51
61
7
78
8
81
81
9
94
91
Thickness
1
1f
11
1}
11
11
2
21
21
21
21
21
21
21
Columns,
Diameter at top
4
41
5f
51
6
7
8
81
91
91
91
10
101
101
Diameter at bottom
41
51
61
6}
6}
71
9
97
101
101
11
111
111
12
Centre to centre of
Air-pump, side rods trans-
versely
291
341
371
391
421
471
53
55}
601
63
67
681
70
72
Beams, do.
33
39
421
45
48
54
60
63
69
69
72
78
80
83
Frames, do.
21
23
25,
26
27
30
34
34
40
40
42
44
45
46
Engines, do
66
72
76
80
84
88
96
100
108
108
112
126
128
130
Length of steam port
71
84
10
11
111
13
15
181
181
19
19
20
20
21
Breadth of steam port
11
11
2
21
21,
21
8
3
4
4
41
41
41
41
Fort valve passage, depth
2
2
21
21
34
34
4
41
5
51
51
6
6}
7
64
44
width
13
14
151
17
18
20
24
26
28
28
29
31
31
32
Beam,
Breadth at middle
14
18
19
21
23
25
28
29
33
34
35
36
38
39
Breadth at ends
5
6
61
73
8
81
10
10}
12
121
124
14
15
151
Thickness
1
11
11
11
11
11
11
2
21
21
21
21
21
21
75
Digitized by Google
594
ENGINES, SUMMARY OF.
TABLES OF DIMENSIONS, &c., of 63 STEAM VESSELS, and of their ENGINES and PROPÈLLERS; selected from
a more extended list, with the view of presenting only those of which the complete particulars are recorded.
Nore.-The tonnage is according to the old builders' measurement. In the column showing the material of each vessel,
the letter W. signifies Wood, and I. Iron.
Length.
Number.
Name of Vessels.
Date of
launch.
Material.
Tonnage.
Between
Over
Of
all.
keel.
perpendi-
Depth.
Mean
draught.
Extreme
breadth.
culars.
ft. in.
ft. in.
ft.
in.
ft. in.
ft. in.
ft.
in.
1
Actseon, &c.
1837
W.
552
171
o
17 8
10 o
25 10
2
Agir
1841
I.
254}
150 0
145
0
10 1
5 8
19 o
3
Alice
1839
I.
170
95
0
9
0
4 6
20 0
4
Arcadia, &c.
1840
W.
1200
228 0
206
0
22 6
16 6
34 6
5
Archimedes
1836
W.
237
125
0
107
0
13
0
9
4
22 6
6
Avon and Severn
1841
W.
1354
238 0
213
0
30 6
17
6
36 6
7
Berenice
1836
W.
646
148
5
164
10
20 0
13
0
28
8
8
Black Eagle
W.
496
136 9
155
0
14 10
10 6
26
1
9
Blackwall
1842
I.
2581
145
0
9 10
5 0
19 1
10
British Queen
1838
W.
1862
275 0
27 6
17 0
40 0
11
Clyde, &c
1841
W.
1354
238 0
213 0
23
6
17 6
36
6
12
Colchis, &c.
1837
W.
4331
156
0
13 6
9 6
24
0
13
Cormorant
1843
W.
1110
210 0
180
0
21 0
36 0
14
Courier
1841
I.
310
158 water line
9 o
1 4
20 0
15
Cyclops
1839
W.
1195
216 6
23 0
15 6
35 6
16
Dart.
I.
48
81
0
7
0
2 3
11 0
17
Dee, &c
1841
W.
1354
213
0
30 6
17 6
36
6
18
Devastation
1841
W.
1100
210 0
180 0
21 0
36 0
19
Dolphin
1839
I.
107
110 0
7
6
2 3
14
0
20
Dundalk
1834
I.
560
170 fore rake
16 0
10 6
26 0
21
Dundee, &c
1834
W.
650
170 0
17
6
11 6
28 0
22
Eclip&e
1840
I.
2771
156 0
11 0
5 6
19 o
23
Enterprise
1839
I.
92
76 6
8 0
3 9
16
0
24
Era
I.
60
85
0
5 11
2 5
12
0
25
Fairy
1845
I.
260
145 0
10 6
5 0
21 0
26
Father Thanes
1840
I.
247
140
0
10 0
4 0
19
0
27
Fulton
W.
181
6
deck
10 0
34 6
28
Grappler
1845
I.
557
165 0
17
0
10 0
26 6
29
Great Britain
1844
I.
3443
320 0
289 0
32 6
16 0
51 0
30
Great Liverpool
1837
W.
1140}
209
5
19
8
16 0
30 10
31
Great Northern
1842
W.
1430
247 0
221 0
26
0
18 0
37
0
32
Great Western
1838
W.
1321
236 0
23 3
16 0
35 4
33
Hamlet
1842
I.
130
96 0
9
6
5 6
17
o
34
Herne
1844
I.
355
155
6
10 0
6 2
21 6
35
Hibernia
1842
W.
1350
218 fore rake
24 0
17
6
36
o
36
India
W.
1000
189
0
28 0
32 0
87
Invincible
1844
I.
125
0
8 0
5 6
17
8
38
Isis and Trent.
1841
W.
1298}
215 0
23
0
17
3
36 0
39
Lady Burgoyne
1843
I.
126
0
9
6
4
9
17
6
40
Locomotive
1841
I.
70
105
0
6 6
2 6
11
6
41
Medea
1843
W.
807
179
4
20 0
14
0
31 11
42
Nimrod
1843
I.
591
175 0
180
0
16
0
11 0
26
0
43
Nile
W.
911
180 0
deck
20 "
13 6
33
0
44
Northern Light Yacht
1845
I.
3031
146
3
deck
142
0
12
9
6 0
21
o
45
Peloro
1843
W.
252
130 0
11
2
20
21
46
Penelope
1842
W.
1630
215 main deck
25 0
40 0
47
Precursor
1841
W.
1476
244 0
225
0
25 0
17 0
37 0
48
President
1840
W.
1840
265 0
30 0
17 0
41 0
49
Prince Albert
I.
300
155
0
9
6
.4 6
19 6
50
Prince of Wales
1842
I.
585
160 0
15 6
7.9
26 6
51
Princess Royal
1841
I.
800
185 0
17
0
10 0
28 0
52
Princess Alice
1843
I.
260
145 0
10 6
6 6
20 0
53
Railway
1842
I.
2581
145 0
9 10
5 3
19
1
54
Rainbow
1837
I.
581
190
0
12 0
6 0
25 0
55
Retribution
1844
W.
1710
192 10
220
0
26 4
18 0
40 6
56
Rocket
1842
I.
70}
90
0
7
4
12 8
57
Rose, &c
1840
I.
306
148
0
11
6
6 6
20 6
58
Ruby
1836
W.
2721
141 91
155 0
10
2
4 6
19 0
59
Styx, &c.
1839
W.
1057
180 0
duk
21
0
14 9
36 2
60
Thunderbolt
1842
W.
174
0
deck
21
0
14 6
36 0
61
Vernon
1841
W.
1000
170 0
22
0
15 6
36
0
62
Water Witch
I.
.
123 0
5
6
2
9
16
4
6:)
William Wi'berforce
1810
W.
650
200 0
17
0
10
0
27
0
Digitized by Google
ENGINES, SUMMARY OF.
595
PROPELLING MACHINERY.
NOTE.-In the last column, showing the description of engines, the abbreviations S. L. signify Side Lever; D. A. Dirret
Action; O. Oscillating; St. Steeple; D. C. Doub.e Cylinder; H. P. High Pressure.
Stroke.
Number of
Horse power
Number.
Diameter of
Paddle wheel's
Kind of
of
Diameter.
engines.
each engine.
cyllnders.
No. per
boards.
engines.
Length.
minute.
in.
ft. in.
ft. in.
ft. in. ft. in.
1
2
146
62
5 9
20
24 6
8 10 X 2 3
2
2
41
361
3 0
30
16 0
7 6 X 1 4
S.L.
3
2
30
31
3 3
14 0
D.A.
4
2
210
72
6 10
16
28 0
9 0 X 3 0
S.L.
5
2
42
37
3 0
26
screw
6
2
230
7 0
16
30 0
S.L.
7
2
118
56
5 6
21
23 0
8 6 X 2 1
S.L.
8
2
135
62
4 6
23 0
5 6 X 4 0
O.
9
1
92
55
3 0
31
15 6
9 10 X 1 2
St.
10
2
2441
771
7 0
16
30 0
9 6 X 2 81
S.L.
11
2
230
744
7 6
15
30 0
S.L.
12
2
62
42
4 6
23
17 0
8 0 X 1 9
S.L.
13
2
158
651
5 3
22
26 8
8 3 X 2 0
D.A.
14
2
35
34
3 0
28
15 0
8 0 X 1 11
O.
15
2
154
64
5 6
21
26 0
8 0 X 1 10
D.A.
16
2
101
20
2 0
35
11 0
4 6 X 0 11
17
2
217
73
7 0
16
28 6
9 6 X 2 6
S.L.
18
4
112
54 1-16th
6 0
18
26 0
9 0 X 2 1
D.C.
19
2
21
28
2 0
85
10 4
4 8 X 1 6
S.L.
20
2
140
61
5 6
21
24 9
8 8 X 2 1
S.L.
21
2
126
58
5 6
21
24 0
8 0 X 2 2
S.L.
22
1
100
54}
4 0
28
16 6
9 0 X 1 3
St.
23
2
21
271
2 6
34
12 6
5 4 X 1 2
S.L.
24
2
12
17] and 29
1 8
34
10 4
5 o X 1 0
D.C.
25
2
54
42
8 0
50
screw
O.
26
2
371
35
3 of
30
18 6
8 6 X 1 3
O.
27
2
250
50
9 0
25
22 5
11 6 X 3 0
28
4
110
40
4 6
25
21 0
8 0 X 1 6
D.C.
29
4
300
88
6 0
18}
screw
30
2
229
75
7 0
16
28 5
S.L.
31
2
162
68
4 6
22
screw
32
2
220
731
7 0
16
28 9
10 0 X 2 6
S.L.
33
2
21
271
2 8
88
11 0
5 6 X 1 8
S.L.
34
2
60
431
3 6
29
18 6
11 0 X 1 6
S.L.
35
2
250
77f
7 6
15
30 4
10 0 X 3 0
S.L.
36
2
151
63
5 9
20
26 6
8 0 X 2 3
S.L.
37
1
83
49
4 2
314
16 0
5 8 X 1 2
St.
38
2
225
74¥
7 0
15
29 0
10 0 X 3 0
S.L.
89
2
46
39
3 0
32
16 0
8 0 X 1 4
O.
40
2
51
4 0
27
H.P.
41
2
112
557
5 0
22
24 0
5 8 X 4 6
S.L.
42
2
160
66
5 3
22
24 6
8 6 X 2 7
D.A.
43
2
132
60
5 2
22
22 0
9 7 X 2 9
S.L.
44
2
76
47
4 3
25
19 0
7 6 X 1 10
O.
45
2
50
391
3 6
29
15 6
8 0 X 1 4
S.L.
46
2
320
91
6 0
18
30 0
10 0
D.A.
47
2
260
80
7 0
16
28 0
S.L.
48
2
266
80
7 6
15
31 0
S.L.
49
2
50
40
3 4
32
17 6
9 0 X 1 4
D.A.
50
2
135
61
5 0
22
25 0
6 9 X 2 0
St.
51
2
208
78
6 3
17
29 0
7 9 X 2 4
St.
52
2
60
48
8 6
30
18 5
7 0 X 2 3
D.A.
53
2
46
39
8 0
33
15 6
9 8 X 1 2
O.
54
2
88
50
4 6
25
21 0
9 10 X 1 8
St.
55
4
400
72
6 0
34 0
13 0 X 2 6
D.C.
56
2
10
19
2 0
40
9 8
3 8 X 0 10
O.
57
2
53
40.1
3 6
29
17 0
8 0 X 1 6
S.L.
58
2
511
40
3 6
30
17 6
9 2 X 1 3
S.L.
59
2
142
62
5 3
20
26 0
8 3 X 1 10
D.A.
60
2
163
67
5 0
20
26 0
7 10
D.A.
61
1
28
30
8 0
32
14 0
S.L.
62
2
16}
22
4 0
45
10 0
D.A.
63
2
140
60
6 0
20
24 0
8 6 X 2 0
S.L.
Digitized by Google
596
ENGINES, SUMMARY OF.
The following are considered in England the most approved proportions for steam vessels:-
Length of keel
1.
Breadth of beam
fth.
Depth of vessel
10ᵗʰ.
Centre of paddle boxes fths from the stern end of the keel, and fths from the stern post.
LOCOMOTIVE ENGINES.-TABLE containing the velocity of the pistons, that of the circumference
of the driving wheels being taken as 1.
Stroke of
the Pistons.
Diameters of Driving Wheels.
in.
4ft. Oin.
4ft. 6in.
5ft. Oin.
5ft. 6in.
6ft. Oin.
6ft. 6in.
7ft. 0in.
7ft. 6in.
8ft. Oin.
20
0.2652
0.2393
0.2122
0.1929
0.1768
0.1632
0.1516
0.1414
0.1326
19
0.2519
0.2273
0.2016
0.1832
0.1679
0.1550
0.1440
0.1343
0.1259
18
0.2386
0.2153
0.1910
0.1736
0.1591
0.1468
0.1364
9.1272
0.1194
17
0.2254
0.2034
0.1803
0.1640
0.1503
0.1387
0.1288
0.1202
0.1127
16
0.2121
0.1914
0.1697
0.1543
0.1415
0.1305
0.1213
0.1131
0.1061
15
0.1989
0.1795
0.1591
0.1447
0.1826
0.1224
0.1137
0.1060
0.0994
14
0.1856
0.1675
0.1485
0.1350
0.1237
0.1141
0.1061
0.0990
0.0928
13
0.1724
0.1555
0.1379
0.1254
0.1149
0.1061
0.0985
0.0919
0.0862
12
0.1591
0.1436
0.1273
0.1157
0.1061
0.0979
0.0909
0.0848
0.0796
Application of this table for finding the tractive power of locomotive engines.-Multiply the sum of
the areas of the two pistons by the effective pressure of the steam in pounds, and further, that product
by the coefficient in the table (belonging to its driving wheels and stroke of the pistons), and this new
product will be the traction of the engine in pounds.
Ex. A locomotive engine to have 5 feet 6 inch driving wheels, cylinders of 13 inches diameter by
18 inches stroke, and the effective pressure of the steam to be 40 lbs. on the square inch what is its
traction 1
(2 X 132.66) 40 X 0.1736
1842.39 lbs. of traction.
If it be required to know the number of tons the engine is able to draw on a level, divide its traction
by the friction in pounds.
If the engine is to go up inclines, then add to that friction the gravity in pounds due to a ton on that
incline, and use this sum as a divisor for the traction: the quotient will be the number of tons the engine
is capable to rise up that incline with. In both cases is the weight of the engine and its tender in the
quotient included.
Explanations.-By effective pressure is understood the pressure of the steam above the pressure of
the atmosphere, less the number of pounds necessary to keep the engine by itself just in motion.
Friction, the power necessary to move a mass along, which is generally taken to be, on railways,
equal to 10 lbs. for every ton.
Gravity, the power to overcome the tendency of a mass or load to descend an incline, being always
equal to the quotient of the product of the load, and height of the incline, divided by the length of the
incline.
Therefore the above engine would draw
1842.39
= 184 tons on a level;
10
and, on an incline, say as 1 in 300,
Friction = 10 lbs.
Gravity = 1 X 2240 = 7.466 lbs.
300
17.466 lbs. Consequently,
1842.39
= 105.5 tons up an incline of 1 in 300.
17.466
If the weight of the engine, with its tender, be taken at 18 tons, it will draw a net gross load of
166 tons on a level, and
87.5 tons up an incline of 1 in 300.
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ENGINES, SUMMARY OF.
597
TABLE showing the Speed of an Engine, when the time of performing a 1, 1, or 1 Mile, is given.
Time of
Time of
Time of
Time of
Time of
Time of
Speed per
hour.
performing
performing
performing
Speed per
hour.
performing
performing
performing
t mile.
t mile.
1 mile.
t mile.
t mile.
1 mile.
Miles.
min.
sec.
min.
sec.
min.
sec.
Miles.
min. sec.
miu. sec.
min.
sec.
5
3
0
6
0
12
0
53
0 17.
0 34.
1
7.9
6
2 30.
5
0
10
0
54
0 16.7
0 33.3
1
6.6
7
2
8.6
4 17.2
8 34.3
55
0 16.4
0 32.7
1
5.4
8
1 52.5
8 45.
7 80.
56
0 16.1
0 32.1
1
4.3
9
1 40.
8 20.
6 40.
57
0 15.8
0 31.6
1
3.1
10
1 30.
3
0
6
0
58
0 15.5
0 31.
1
2.
11
1 21.8
2 43.6
5 27.3
59
0 15.2
0 30.5
1
1.
12
1
15.
2 30.
5
0
60
0 13.
0 30.
1
0
13
1
9.2
2 18.4
4 37.
61
0 14.7
0 29.5
0 59.
14
1
4.3
2
8.6
4 17.1
62
0 14.5
0 29.
0 58.
15
1
0
2
0
4
0
63
0 14.3
0 28.5
0 57.
16
0 56.2
1 52.4
8 45.
64
0 14.1
0 28.1
0 56.2
17
0 52.9
1 46.
3 81.8
65
0 -18.8
0 27.7
0 55.4
18
0 50.
1
40.
3 20.
66
0 13.6
0 27.2
0 54.5
19
0 47.4
1
34.8
3
9.5
67
0 13.4
0 26.9
0 53.7
20
0 45.
1 30.
3
0
68
0 13.2
0 26.5
0 52.9
21
0 42.8
1 25.6
2 51.4
69
0 13.
0 26.1
0 52.2
22
0 40.9
1 21.8
2 43.6
70
0 12.8
0 25.7
0 51.4
28
0 89.1
1 18.2
2 86.5
71
0 12.7
0 25.3
0 50.7
24
0 37.5
1
15.
2 80.
72
0 12.5
o 25.
0 50.
25
0 36.
1
12.
2 24.
73
0 12.3
0 24.6
0 49.3
26
0 34.6
1
9.2
2 18.4
74
0 12.1
0 24.3
0 48.6
27
0 33.3
1
6.6
2
13.3
75
0 12.
0 24.
0 48.
28
o 32.1
1
4.3
2
8.6
76
0 11.8
0 23.7
0 47.3
29
0 31.1
1
2.1
2
4.1
77
0
11.7
0 23.4
0 46.7
30
0
30.
1
0
2
0
78
0 11.5
0 23.1
0 46.1
31
0 29.
0 58.
1 56.1
79
0 11.4
0 22.8
0 45.6
32
0 28.1
0 56.2
1 52.5
80
0 11.2
0 22.5
0 45.
33
0 27.3
0 54.6
1 49.1
81
0 11.1
0 22.2
0 44.4
34
0 26.5
0 53.
1 46.
82
0
10.8
0 21.9
0 43.9
35
o 25.7
0 51.4
1 43.
83
0 10.8
o 21.7
o 43.4
36
0 25.
0 50.
1 40.
84
0
10.7
0 21.5
0 43.
37
0 24.3
0 48.6
1 37.3
85
0
10.6
0 21.2
0 42.3
38
0 23.7
0 47.4
1 34.3
86
0
10.5
0 20.9
0 41.9
89
0 23.
0 46.1
1
32.3
87
0
10.3
0 20.7
0 41.4
40
0 22.5
0 45.0
1 30.
88
0
10.2
0 20.4
0 40.9
41
0 21.9
0 43.9
1 27.8
89
0
10.1
0 20.2
0 40.4
42
0 21.4
0 42.8
1 25.7
90
0
10.
0 20.
0 40.
43
0 20.9
0 41.9
1 23.7
91
0
9.9
0 19.7
o 89.5
44
0 20.4
0 40.9
1 21.8
92
0
9.8
0 19.5
o 39.1
45
0 20.0
0 40.
1 20.
93
0
9.7
0 19.3
0 38.7
46
0 19.5
0 39.1
1
16.6
94
0
9.6
0 19.1
0 38.3
47
0 19.1
0 38.3
1 16.6
95
0
9.5
0 18.9
0 37.9
48
0 18.7
0 37.5
1
15.
96
0
9.4
0 18.7
o 37.5
49
0 18.3
0 86.7
1
18.4
97
0
9.3
0 18.5
0 37.1
50
0 18.
0 36.
1 12.
98
0
9.2
0 18.4
0 36.7
51
0 17.6
0 35.3
1 10.6
99
0
9.1
0 18.2
0 36.4
52
0 17.3
0 34.6
1
9.2
100
0
9.
0 18.
0 36.
NOTE.-If the distance of a journey, and the time it was performed in, be given, and the speed per hour be required,
divide the time elapeed by the distance, and look in the table for the nearest speed belonging to that quotient.
Example. A distance of 31 miles was performed in 57 minutes; it is required to know the average speed per hour.
57 = 1 minute 50.3 seconds.
31
The nearest speed in the table to that time is 33 miles.
TABLE showing the Circumferences of different Driving Whoels.
Diam. of Wheel.
Length of Circumference.
Diameter of Wheel.
Length of Circumference.
ft. in.
feet.
n. in.
feet.
4 0
12566
6 6
20-419
4 6
13927
7 0
21990
5 0
15707
7 6
23561
5 6
17278
8 0
25-132
6 0
18849
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598
ENGINES, SUMMARY OF.
TABLE showing the Number of Revolutions of the Driving Wheels, or strokes of the Piston, per minute,
while the Engine is performing a known number of miles per hour.
Diam. of
Wheel
4 ft.
Diam. of
Wheel
É e
Diam. of
Wheel
e
Diam. of
Wheel
5 ft. 6 in.
Diam. of
Wheel
: d
Diam. of
Wheel
lb. 9 è
Diam. of
Wheel
7 ft.
Diam. of
Wheel
7 6 in.
Diam. of
Wheel
2.
No. of
No. of
No. of
No. of
No. of
No. of
No. of
No. of
No. of
revolutions
revolutions
revolutions
revolutions
revolutions
revolutions
revolutions
revolutions
revolutions
Number of miles
performed per Hour.
or strokes
or strokes
or strokes
or strokes
or strokes
or strokes
or strokes
or strokes
or strokes
per min.
per min.
per min.
per min.
per min.
per min.
per min.
per min.
per min.
35.03
31.59
28.03
25.47
23.34
21.55
20
18.67
17.5
5
70-06
63.17
56.06
50.95
46.68
4310
40
37.34
35.0
10
105.09
9476
84-09
76.42
70.02
64.65
60
56.01
52.5
15
140-12
12636
112-12
101-70
93.36
86.20
80
74.68
750
20
175.15
15795
140:20
12737
11670
107.75
100
93.35
875
25
210-18
189.54
168-18
152.85
140-04
12930
120
112.02
105.0
30
24521
22113
19621
17729
163:38
150.85
140
130-69
122.5
35
28024
252-72
22424
203-76
18672
172.40
160
14936
140·0
40
31527
284'80
25227
22923
210-06
19395
180
16803
1575
45
35030
31590
28030
25475
23340
21550
200
18670
175.0
50
88533
34749
308:33
280.17
25674
23705
220
20537
192.5
55
42036
37908
33686
305-64
280.08
258 60
240
22404
210-0
60
45539
416.67
36439
33111
803.42
280-15
260
242'71
2275
65
490-42
442.19
89242
856.58
32676
301.70
280
261.38
2450
70
525.45
473.85
420-50
372-05
350.10
323.25
300
280.05
262.5
75
560.48
505.50
448-48
40760
373.44
34480
320
298.73
280-0
80
595.51
53689
477-01
43299
39678
366.35
340
31789
2975
85
63054
568.60
50451
458.55
42012
387.90
360
336-06
315-0
90
66557
600-19
53257
48393
443'46
409.45
380
35473
3325
95
700-60
63178
560-63
50950
46680
431-00
400
37340
350 0
100
NOTE-To find the velocity the piston is travelling at in feet, per minute, multiply the number of
revolutions of its driving wheels, in the table, by twice the length of its stroke in feet.
Ex. What is the speed of the piston of an engine with 6-feet driving wheels and 15-inch stroke, when
going at the rate of 50 miles an hour 1
By means of the table:
233.4 revolutions X (2+⁵) = 5835 feet per minute.
The number of revolutions of driving wheels is inversely as their diameters, and in direct proportion
to the number of miles performed.
Ex. How many revolutions have the driving wheels of an engine to make when it is going at 95
miles an hour, their diameter being 9 feet 6 inches
According to the table, a 4-feet wheel would have to make 66557 revolutions; therefore
95 : 4 : : 66557 : 4 X 66557
= 280 revolutions.
95
The driving wheels of an engine make 35.03 revolutions when going at the rate of 5 miles an hour
how many will they make when going at 9 miles 1
5 : 9 :: 35-03 : 9 X 35.03
= 63-05 revolutions.
5
TABLE of the Areas of Cylinders, from 9 to 15 inches diameter.
Diameter of
Cylinder.
Area of Cylinder.
Diameter of
Cylinder.
Area of Cylinder.
Inches.
Square Inches.
Inches.
Square Inches.
9
68.58
121
122.65
10
78.5
13
132.66
101
86.56
131
143-02
11
95.01
14
153.96
111
10384
14}
165-04
12
118.07
15
17662
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ENGINES, SUMMARY OF.
599
TABLE containing the Speed of a Locomotive Engine, in feet per minute, when the rate it is going at in
miles per hour is given.
Miles
Velocity
Miles
Velocity
Miles
Velocity
Miles
Velocity
performed
in feet
performed
in fret
performed
in feet
performed
in feet
per hour.
per minute.
per hour.
per minute.
per hour.
per minute.
per hour.
per minute.
2
176
28
2364
54
4752
80
7040
4
352
30
2640
56
4928
82
7216
6
528
32
2816
58
5104
84
7392
8
704
34
2992
60
5280
86
7568
10
880
36
3168
62
5456
88
7744
12
1056
38
3344
64
5632
90
7920
14
1232
40
3520
66
5808
92
8096
16
1408
42
3696
68
5984
94
8272
18
1584
44
3872
70
6160
96
8448
20
1760
46
4048
72
6336
98
8624
22
1936
48
4224
74
6512
100
8800
24
2112
50
4400
76
6688
26
2288
52
4576
78
6864
Application of this table for finding the useful effect of an engine.
RULE -Multiply the resistance of the weight or friction of the train in pounds, by the speed of the
engine in feet per minute, and divide the product by 33000.
Ex. An engine to which are attached 6 carriages, weighing altogether 24 tons, going at the rate of
50 miles an hour, what is its useful effect!
(10 X 24) X 4400
33000
= 32 horses' power.
MARINE ENGINES.-WITH SIDE WHEELS.
CONDENSING.-For 550 square feet of immersed section, with a displacement of 2800 tons.
Cylinders. Two, each of 215 cubic feet in capacity.
Condensers. 75 cubic feet in each. Air pumps. 50 cubic feet in each.
Force Pumps. 71 inches diameter by 46 inches stroke.
Water Wheels. 28 feet in diameter by 11 feet in width, 21 arms in each; buckets, (divided both in
depth and length,) 14 and 16 inches.
Shafts, (wrought-iron.) Diameters of journals, 17 184, and 12 15 inches.
Boilers. 6000 square feet of fire and flue surface; flues 40 feet in length, including steam chimney.
Grates. 260 square feet. Steam Room. 1770 cubic feet.
Pressure. Average, 10 lbs. per square inch, cut off at t of the stroke of the piston: attainable, 20 lbs.
Revolutions. From 12 to 184 per minute. Dip of Wheel. 5 feet at load-line.
Consumption of Fuel. 35 to 40 tons of bituminous coal per day.
Weights. Engines, boilers, water wheels, water in boilers, coal bunkers, engineers' stores, tools, &e.,
&c., 490 tons of 2240 lbs., viz.:-
Engines
211 tons.
Water wheels
47 tons.
Boilers and smoke pipe
120
"
Engineer's stores, tools, dic.
7
"
Water in boilers
82
"
Coal bunkers
23
"
Hull. Launching weight, 1280 tons.
CONDENSING.-For 200 square feet of immersed section, with a displacement of 650 tons. Length,
162.5 feet between perpendiculars 27 feet beam; and 12 feet depth of hold. Load-line, 8.25 feet.
Cylinders. Two, each of 56.5 cubic feet in capacity.
Pressure. 16 lbs. per square inch, cut off at I the stroke.
Revolutions. 22 per minute.
Water Wheels. 21 feet in diameter by 7.5 feet face, with 16 arms. Dip. 2.5 feet.
Buckets. 16 and 10 inches in depth.
Boilers. 1900 square feet of fire and flue surface. Grates. 84 square feet. Steam Room. 480
cubic feet.
Fuel, (natural draught.) At 19 revolutions, 1750 lbs. of anthracite coal per hour.
Weights.
Engines and frames
196,000 lbs.
Water in boilers
50,000 lbs.
Boilers and Chimney.
68,000 "
Tools and stores, dc.
4,500 "
Coal bunkers
16,000 "
834,500 lbs.
Weights of metals in engines, (unfinished.)
Cast-iron
100,500 lbs.
Composition
11,300 lbs.
Wrought-iron
82,000 "
Copper
6,700 "
Hull. Wrought-irou, weighing 507,387 lbs.
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600
ENGINES, SUMMARY OF.
GREAT WESTERN." CONDENSING.-For 2372 tons displacement, (load-line,) with an area of immersed
section of 480 square feet. Length between perpendiculars, 212 feet; beam, 35 feet 4 inches :
depth of hold, 23 feet 2 inches; draught of water, 17 feet.
Cylinders. 781 inches in diameter by 7 feet stroke of piston. Pressure. 81 lbs. per square inch.
Revolutions. 121 per minute.
Water Wheels. 28 feet in diameter by 10 feet face. Buckets. 20 and 10 inches in depth.
Tonnage. Vessel, 1340 tons. Engine room, 641.5, or one-half of the whole.
Weights. Engines, 300 tons. Boilers, 100. Water in boilers, 80. Total, 480.
Centre to centre of engines, 13 feet.
H. M. RETRIBUTION." CONDENSING.-For 1641 tons burden, with 600 square feet of immersed section.
Length between perpendiculars, 220 feet; beam 40 feet 6 inches; depth of hold, 26 feet 4 inches.
Cylinders. Four, of 72 inches in diameter by 8 feet stroke of piston, (direct action.)
Water Wheels. 33 feet in diameter by 13 feet in width. Revolutions. 15 per minute. Dip of buckets,
7 feet; depth, 30 inches.
Boilers. Four, containing 3418 square feet of fire and flue surface, 2272 cubic feet of steam room,
and 704 cubic feet in furnaces, over the grate-bara.
Length of engine-room, 75 feet.
SCREW PROPELLER, (ERICSSON.)
CONDENSING.-For 338 square feet of immersed section, with a displacement of 1046 tons.
Length, 156.5 feet between perpendiculars; beam, 30.5 feet; hold, 21.5 feet; tonnage, 673.53.
Cylinders. Two, each of 54 cubic feet in capacity. Pressure. 25 lbs. per square inch, cut off at t
of the stroke.
Propeller. 120 square feet of surface. Pitch. 35 feet. Diameter. 14 feet. Revolutions. 36 per
minute.
Shafts, (wrought-iron.) Diameter of journals, 12 X 16 inches.
Boilers. 2500 square feet of fire and flue surface. Flues, 50 feet in length. Grates. 134 square feet.
Steam Room. 1150 cubic feet.
Fuel. 1 ton of anthracite coal per hour, (blast.)
Weights.
Engines
92 tons.
Water in boilers
34 tons.
Boilers
17 "
Coal bunkers
6 "
Hull. Launching weight, 418 tons. Sails. Area in square feet, 11,762. Surface of sails in propor-
tion to immersed section, 3492 square feet to 1.
RIVER ENGINES.-WITH SIDE WHEELS.
NIAGARA." CONDENSING.-For 123 square feet of immersed section. Length of vessel, 265 feet; beam.
28 feet 6 inches; depth of hold, 9 feet 8 inches; draught, (loaded,) 4 feet 9 inches.
Cylinder. 216 cubic feet in capacity. Condenser. 88 cubic feet. Air-pump. 33.5 cubic feet.
Force-pumps. 51 inches diameter by 41 feet stroke.
Pressure. 40 to 45 lbs. per square inch, cut off at half the stroke of the piston. Revolutions. 24 per
minute.
Water Wheels. 30 feet in diameter by 11 feet face. Arms. 24 in each flange. Buckets. Two, of 15
inches deep. Dip, (at load-line.) 30 inches.
Shafts, (wrought-iron.) Journal, 14 inches.
Boilers. Two, of 27 feet in length by 10 feet front. Shell. 8 feet 6 inches in diameter. Fire and
Flue Surface. 3000 square feet. Grates. 108 square feet. Steam Room. 1200 cubic feet.
Fuel. 3200 lbs. of anthracite coal per hour, (maximum.)
Blowers. Two, of 9 feet in diameter. Fans. Ten, of 24 inches by 3 feet face.
Blowing-engines. Two, of 10 inches diameter of cylinder by 12 inches stroke. Revolutions. 150 per
minute.
Weights.
Engines
186,000 lbs.
Boilers
65,000 64
Wood, in engines and wheels
29,000 "
Water in boilers
76,000 "
Total
356,000 lbs.
"SOUTH AMERICA." CONDENSING.-For 132 square feet of immersed section. Length of vessel, 250
feet; beam, 27 feet; depth of hold, 9 feet; draught, (loaded,) 5 feet.
Cylinder. 175 cubic feet in capacity. Air-pump. 38.5 cubic feet.
Condenser. 72 cubic feet. Force-pumps. 5 inches diameter by 4 feet stroke.
Pressure. 35 to 40 lbs. per square inch, cut off at half the stroke of the piston.
Revolutions. 23.5 to 23 per minute.
Water Wheels. 29 feet in diameter by 11 feet face. Arms. 24 in number. Buckets. Two divisions,
and 30 inches deep. Dip, (at load-line.) 30 inches.
Shafts, (wrought-iron.) Diameter of journal, 13 inches.
Boilers. Two, 27 feet in length by 9.5 in width. Fire and Flue Surface. 8000 square feet. Shell.
8 feet in diameter. Grates. 100 square feet. Steam Room. 1000 cubic feet.
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ENGINES, SUMMARY OF.
601
Consumption of fuel. 3000 lbs. of anthracite coal per hour, (maximum.)
Blowers. Four, 4 feet diameter by 26 inches face. 4 arms. Fans. 13 inches deep. Revolutions. 75
per minute.
Blowing-engines. Cylinder, 8 inches in diameter by 12 inches stroke.
Weight of boilers. 62,000 lbs.
The above engines and boilers were designed and constructed at the Phoenix Foundry, New York.
CONDENSING.-For 160 square feet of immersed section. Length of vessel, 335 feet; beam, 35 feet;
depth of hold, 11 feet 6 inches.
Cylinder. 313 cubic feet in capacity. Air-pump. 54 cubic feet.
Pressure. 38 lbs. per square inch. Revolutions 22 per minute.
Water Wheels. 34 feet in diameter by 10 feet 8 inches face. Buckets. 30 inches deep.
Boilers. Shell. 91 feet in diameter. Surface. 3660 square feet. Steam Room. 1570 cubic feet.
Grates. 145 square feet.
Blowing-engines. Two cylinders, of 14 inches diameter by 14 inches stroke. Two blowers. 10 feet
in diameter by 2 feet in width. Ten fans in each, of 26 inches in depth. Revolutions. 100 per minute.
Fuel. 3000 lbs. of anthracite coal per hour.
NON-CONDENSING. For 300 square feet of immersed section. Vessel 260 feet in length, 38 feet beam,
and 8 feet draught when loaded.
Cylinders. Two, each 30 inches in diameter by 10 feet stroke of piston, (983 cubic feet.) Force
pumps. 64 inches in diameter by 25 inches stroke.
Water wheels. 33 feet in diameter by 15 feet in width, 19 arms in each. Buckets. 36 inches deep.
Shafts, (cast-iron.) Diameter of journals, 16 and 14 inches.
Connecting-rod. 35 feet in length. Piston-rod. Diameter, 6 inches.
Steam valves. 50 square inches each. Exhaust valves. 63 square inches.
Boilers. Five, of 42 inches in diameter by 34 feet in length, with two return flues in each, 16 inches
in diameter, having 2278 square feet of heating surface. Grates. 84 square feet.
Boiler plates. Shells. t of an inch in thickness. Flues. Full t of an inch.
Pressure. 75 to 100 lbs. per square inch, cut off at 1 the stroke of the piston.
Revolutions. 16 to 21 per minute. Dip of wheel. 5 feet when loaded.
Consumption of fuel. 2.3 cords yellow pine per hour.
Weights. Engines, 160 tons; boilers, 9000 lbs.
NON-CONDENSING.-Pressure of steam, 100 lbs. per square inch, cut off at t stroke. Revolutions, 22 per
minute.
Cylinders. 421 cubic feet. Boilers. 1393 square feet of fire and flue surface.
Water wheels. 221 feet in diameter by 10 feet 4 inches face, with 13 inches depth of bucket.
Smoke pipe. 42 inches in diameter X 45 feet high. Area of flues. 1600 square inches.
Fuel. 36 cords western wood in 12 hours.
Furnace. 17 feet in width by 42 in length, and 17 inches in height. Grates. 68 square feet.
NOTE-3275 square feet of fire and flue surface is the proportion for each cubic foot in the cylinders
at the above given revolutions.
STEAM VESSELS.-MARINE.
" GREAT BRITAIN."-Displacement at 16 feet draught, 8000 tons. Length of keel, 289 feet; beam, 51
feet; depth of hold, 32 feet 6 inches.
Plates. t. H, #, and i thick.
Frames. 18 and 24 in. apart. 1 thick, by 35 X 6 inches; by 2.5 X 6 inches, and by 3 X 4 inches, L.
Weight of Hull, (in iron.) 1040 tons.
MICHIGAN."-Displacement at 8 feet 8 inches draught, 658 tons. Length between perpendiculars, 162
feet 6 inches; beam, 27 feet; depth of hold, 13 feet.
Plates. 1. 1, i, 15, 4, and 1' thick.
Frames. 2 feet apart. t and I thick, by 4 X 4.5 inches, 1; and t and i, by 4 X 2.25 inches, L.
Deck beams. i, by 4.5 X 7 inches, L.
Weight of Hull, including bulwarks and berth deck, 507,387 lbs.
SPENOER."-Displacement at 9 feet 3 inches, 440 tons. Length between perpendiculars, 143 feet;
beam, (average,) 20 feet 3 inches; depth of hold, 11 feet 6 inches.
Plates. 1. is. and t of an inch.
Frames. 20 inches apart. 1 thick, by 2.5 X 45 inches, L.
Deck beams. t, by 2.87 X 5.5 inches, L.
Weights.
Platin
125,922 lbs.
Knees
13,845 lbs.
Bulk-heads
11,663
"
Rivets
18,005 "
Keelson
3,093 64
Stanchions
2,997 "
Deck beams
34,463 "
Sundries
20,918 "
Frames
44,661 "
Total
275,567 lbs.
CANAL Волт, (very full built.) Length between perpendiculars, 80 feet; beam, 14 feet; depth of hold,
7 feet.
76
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Plates. Nos. 3 and 4, wire gage.
Frames. 18 inches apart, and È thick by 3 inches wide, 1.
Deck and beams of wood.
Weight of Hull, 42,300 lbs.
SUGAR MILL. For expressing 20,000 lbs. of cane juice per day.-Nox-Condensing ENGINE
Cylinder. 15 inches in diameter by 4 feet stroke.
Pressure. 50 lbs. per square inch, cut off at I the stroke of the piston.
Revolutions. 36 per minute.
Boiler. One of 62 inches in diameter by 30 feet in length, with two 18 inch return flues. Grates. 36
square feet.
Rolls. Two sets of three each, of 24 inches in diameter by 5 feet in length; geered 21 to 36 of engine,
giving a speed of periphery of 15} feet per minute.
Fly-wheel. 18 feet in diameter; weight, 5 tons.
This arrangement of a second set of rolls is a late improvement; its object, that of expressing the
cane a second time. An increase of 30 per cent. is effected by it.
For a crop of 3000 boxes of sugar of 500 lbs. each.
A non-condensing engine, with a cylinder of 11 inches in diameter by 4 feet stroke, making 48 revo-
lutions, with a pressure of steam 60 lbs. per square inch, driving one set of rolls, 24 inches by 4 feet, at
a speed of periphery of 36 feet per minute.
Boiler. 52 inches by 24 feet, with two 16 inch return flues. Grate surface. 25 square feet.
Fly-wheel. 16 feet diameter; weight, 4 tons.
SAW-MILL-NON-CONDENSING ENGINE. Two vertical saws of 34 inches stroke. Lathes, &c.
Cylinder. 10 inches in diameter by 4 feet stroke.
Pressure. 90 to 100 lbs. per square inch, full stroke. Revolutions. 35 per minute.
Boilers. Three, plain cylindrical, 30 inches in diameter by 20 feet in length.
NOTE-This engine has cut, of yellow pine, 30 feet by 18 inches in one minute.
COTTON FACTORY. CONDENSING ENGINE-Driving 13,000 spindles, (mules and throstles,) with 256 looms
for t cloth No. 30.
Cylinders. Two, 22 inches in diameter by 8 feet stroke of piston.
Pressure. 15 to 45 lbs. per square inch, cut off at $ of the stroke.
Revolutions. 50 per minute.
CONDENSING ENGINE, (British.) Driving 22,060 hand-mule spindles, with preparation, 260 looms, and
common sizing.
Engine.-Cylinder, 371 inches diameter by 7 feet stroke; indicated pressure (average) 16.73 lbs. per
square inch; revolutions, 17 per minute.
Friction of engine and shafting, indicated 4.75 lbs. per square inch of piston.
Total power = 1. Available, deducting friction = 717. Estimated power of engine, 134 horses.
Nores-Each indicated horse power will drive
305 hand-mule spindles, with preparation,
or 230 self-acting
or 104 throstle
"
"
or 101 looms with common sizing.
Including preparation:
1 throstle spindle = 3 hand-mule, or 21 self-acting spindles.
1 self-acting spindle = 1} hand-mule spindles.
Exclusive of preparation, taking only the spindle:
1 throstle spindle = 31 hand-mule, or 25 self-acting spindles.
1 self-acting spindle = 11 hand-mule spindles.
The throsties are the common, spinning 34 twist for power-loom weaving: the spindles revolve 4000
per minute. The self-acting mules are, one half spinning 36's weft, spindles revolving 4800; the other
half spinning 36's twist, spindles revolving 5200. The hand-mules spinning about equal quantities of
36's weft and twist. Weft spindles 4700, and twist spindles 5000 revolutions per minute.
Average breadth of looms 37 inches, (weaving 37 inch cloth,) making 123 picks per minute. All
common calicoes about 60 reed, Stockport count, and 68 picks to the inch.
No power consumed by the sizing. When the yarn is dressed instead of sized, one-horse power cast
not drive 80 many looms, as the dressing machine will absorb from 1-6th to 1-7th of the power.
COTTON PRESS. Non-Condensing ENGINE.-For 1000 bales in 12 hours
Cylinder. 14 inches in diameter by 4 feet stroke.
Pressure. 40 lbs. per square inch, at full stroke. Revolutions. 60 per minute.
Boilers. Three, plain cylindrical without flues, 30 inches in diameter by 26 feet in length. Grates,
82 square feet.
Presses. Four, geered 6 to 1, with two screws each of 71 inches in diameter by 18 inch pitch.
Shaft, (wrought-iron.) Journal, 81 inches.
Fly-wheel. 16 feet in diameter; weight, 4 tons.
BLOWING OR BLAST ENGINE-Dimensions of a furnace, engines, &c. At Lonakoning, (Md)
Furnace. Diameter at the boshes 14 feet, which fall in 633 inches in every foot rise.
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Engine, (Non-condensing) Diameter of cylinder 18 inches, length of stroke 8 feet. Revolutions. 12
per minute, with a pressure of 50 lbs. per square inch.
Boilers. Five, each 24 feet in length, and 36 inches in diameter.
Blast cylinders. 5 feet diameter and 8 feet stroke.
At a pressure of from 2 to 21 lbs. per square inch, the quantity of blast is 3770 cubic feet per minute,
requiring a power of about 50 horses to supply it.
For blowing four furnaces, 14 feet in diameter, each making 100 tons of pig iron per week. At Mount
Savage, (Md.)
Engine, (Condensing.) Diameter of cylinder 56 inches, length of stroke 10 feet.
Revolutions. 15 per minute. Pressure. 60 lbs. per square inch, cut off at t of the stroke.
Boilers. Six of 60 inches in diameter, and 24 feet in length, with one 22 inch flue in each, double re-
turned. Grates. 198 square feet.
Blast cylinder. 126 inches in diameter by 10 feet stroke. Revolutions. 15 per minute.
Pressure of blast. 4 to 5 lbs. per square inch.
Area of pipes. 2300 square inches, or 1-5th that of the cylinder.
For blowing two furnaces and two fineries, making 240 tons of forge pig per week.
Engine, (Non-condensing.) Diameter of cylinder 20 inches, length of stroke 8 feet.
Revolutions. 28 per minute. Pressure. 50 to 60 lbs. per square inch, (full stroke.)
Boilers. Six of 36 inches in diameter and 28* feet in length, (without flues.) Grates. 100 square feet.
Blast-cylinders. Two of 62 inches in diameter by 8 feet stroke. Revolutions. 22 per minute. Pres-
sure of blast. 21 lbs. per square inch.
Area of pipes. 3 feet, or 1-6th that of the cylinders.
One blast furnace has two 3 inch and one 31 inch tuyeres, the other has three of 3 inches.
One finery has six tuyeres of 11 inch, and the other, four of 11 inch.
The ore yields from 40 to 45 per cent. of iron. The temperature of the blast is 600°.
PILE-DRIVING. NON-CONDENSING ENGINE-Driving two piles.
Cylinders. Two of 6 inches in diameter by 18 inches stroke.
Pressure. 60 lbs. per square inch, full stroke. Revolutions. From 60 to 80 per minute.
Boiler. Tubular. Shell. 31 feet in diameter by 6 feet in length. Furnace end, 3 feet 9 inches in
width, 31 feet in length, and 6 feet in height.
Rams. 1000 lbs. each, lifted five times in a minute.
Frame. 81 feet in width by 26 feet in length. Leaders. 3 feet in width by 24 feet in height
STEAM-DREDGING MACHINE. NON-CONDENSING ENGINE-For dredging 30 feet from water-line. Six full
buckets per minute.
Cylinder. 12 inches in diameter by 5 feet stroke of piston.
Pressure. 60 to 70 lbs. per square inch, full stroke. Revolutions. 20 per minute, geered 30 of engine
to 1 of buckets.
Boilers. Two of 20 feet in length by 36 inches in diameter, with one 15 inch return flue in each.
Ways. 55 ft. in length by 6 in width. Buckets. Ten of 28 inch. in width by 58 in length, and 14 in depth.
At a depth of 18 ft., ten buckets full of mud are discharged per minute, the engine making 30 revolutions.
NOTE-This engine is geered too slow, being but 21 to 1.
Hulls. Two of 50 feet in length, 12 feet in width, and 9 in depth each; connected on deck, space be-
tween for the ways, 7f feet.
ENGRAVING.-Engraving on Copper is performed by cutting lines representing the subject ona
copper-plate by means of a steel instrument ending in an unequal-sided pyramidal point, such instru-
ment being called a graver or burin, without the use of aquafortis. Besides the graver there are other
instruments used in the process; viz-a scraper, a burnisher, an oil-stone, and a cushion for supporting
the plate. In cutting the lines on the copper the graver is pushed foward in the direction required,
being held in the hand at a small inclination to the plane of the copper. The use of the burnisher is
to soften down lines that are cut too deep, and for burnishing out scratches in the copper it is about
three inches long. The scraper, like the last, is of steel, with three sharp edges to it, and about six
inches long, tapering towards the end. Its use is to scrape off the burr, raised by the action of the
graver. To show the appearance of the work during its progress, and to polish off the burr, engra-
vers use a roll of woollen or felt called a rubber, which is put in action with a little olive-oil. The
cushion, which is a leather bag about nine inches diameter filled with sand for laying the plate on, is
now rarely used except by writing-engravers. For architectural subjects. or in skies, where a series of
parallel lines are wanted. a ruling-machine is used the accuracy of its operation is exceedingly perfect.
This is made to act on an etching ground by a point or knife connected with the apparatus, and bit in
with aquafortis in the ordinary way.
The plate of copper must be perfectly polished, very level, and free from every imperfection: to this
must be transferred an exact copy of the outlines of the drawing. To do this the plate is heated in
an oven or otherwise, very uniformly, till it is sufficiently hot to melt white wax, a piece of which is
then rubbed over it and allowed to spread 80 as to form a thin coat over the whole surface, after which
it is left in a horizontal position till the wax and plate are cold. A tracing being taken of the original
design with a black-lead pencil on a piece of thin tracing-paper, this is spread over the face of the pre-
pared plate with the lead lines downwards, and, being secured from slipping, a strong pressure is made
use of by a press or otherwise, by which operation the lead lines are nearly obliterated on the paper,
being transferred to the white wax on the plate. These pencil marks on the wax are now traced with
40 feet would have afforded much economy of fuel.
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ENGRAVING.
a fine steel point, 80 as just to touch the copper the wax being then melted off, a perfect outline will
be found on the copper; and on this the engraver proceeds to execute and finish his work. With
respect to the process itself it would be useless to speak it depends on manual dexterity and genius,
which it is impossible to teach by description.
Engraving on Steel-The method of engraving is the same as copperplate-engraving, except in cer-
tain modifications in the use of the acids, and therefore, 80 far as the process is concerned no particular
description is necessary; but it will be proper to explain the means employed for decarbonizing the
steel plate 80 as to reduce it to a proper state for being acted upon by the graving tool. Mr. Perkins,
an eminent artist and engineer, (a native of Massachusetta,) has the merit of having established engra-
ving on steel. About the year 1823 he was induced to visit London, where he obtained a patent for
the invention; this was intended principally to prevent the forgery of bank notes, which at that time,
or rather previously to that time, had been carried on to a very fearful extent The method employed
for decarbonizing and recarbonizing the plate may be applicable to many other useful purposes, and
we shall therefore give it in the words of the patentee. In order to decarbonate the surfaces of cast-
steel plates, cylinders, or dies, by which they are rendered much softer and fitter for receiving either
transferred or engraved designs, I use pure iron filings divested of all foreign or extraneous matters.
The stratum of decarbonated steel should not be too thick for transferring fine and delicate engravings;
for instance, not more than three times the depth of the engraving; but for other purposes the surface
of the steel may be decarbonated to any required thickness. To decarbonate it to a proper thickness
for a fine engraving, it is to be exposed for four hours in a white heat, enclosed in a cast-iron box with
a well-closed lid. The sides of the box are made at least three-quarters of an inch in thickness, and
at least a thickness of half an inch of pure iron filings should cover or surround the cast-steel surface
to be decarbonated. The box is allowed to cool very slowly, which may be effected by shutting off all
access of air to the furnace, and covering it with a layer of six or seven inches in thickness of fine
cinders. Each side of the steel plate, cylinder, or die, must be equally decarbonated, to prevent it
from springing or warping in hardening. It is also found that the safest way to heat the plates, cylin-
ders, or dies, is by placing them in a vertical position. The best steel is preferred to any other sort
of steel for the purpose of making plates, &c., and more especially when such plates, &c., are intended
to be decarbonated. The steel is decarbonated solely for the purpose of rendering it sufficiently soft
for receiving any impression intended to be made thereon; it is therefore necessary that after any piece
of steel has been 80 decarbonated, whether it be in the shape of a plate, or a cylinder, or a die, it
should, previously to being printed from, be again carbonated or reconverted into steel capable of
being hardened. In order, therefore, to effect this decarbonization or reconversion into steel, the fol-
lowing process is employed a suitable quantity of leather is to be converted into charcoal by the well-
known method of exposing it to a red heat in an iron retort for a sufficient length of time, or until most
of the evaporable matter is driven off the leather. Having thus prepared the charcoal, it is reduced
to a very fine powder; then take a box made of cast-iron, of sufficient dimensions to receive the plate,
cylinder, or die, which is to be reconverted into steel, so as that the intermediate space between the
sides of the said box and the plate or die may be about an inch. This box is to be filled with the
powdered charcoal, and. having covered it with a well-fitted lid, let it be placed in a furnace similar to
those used for melting brass, when the heat must be gradually increased until the box is somewhat
above a red heat; it must be allowed to remain in that state till all the evaporable matter is driven
off from the charcoal; then remove the lid from the box, and immerse the plate, cylinder, or die, into
the powdered charcoal, taking care to place it as nearly in the middle as possible, so that it may be
surrounded on all sides by a stratum of the powder of nearly a uniform thickness. The lid being re-
placed, the box, with the plate, cylinder, or die, must remain in the degree of heat before described for
from three to four hours, according to the thickness of the body 80 exposed; three hours are sufficient
for a plate of half an inch in thickness, and five hours when the steel is one inch and a half in thick-
ness. After the plate or other piece of steel has been thus exposed to the fire for a sufficient length of
time, take it from the box and immediately plunge it into cold water. Here it is important to observe,
that it is found by experience that the plates or other pieces of steel when plunged into cold water, are
least liable to be warped or bent when they are held in a vertical position, or made to enter the water
in the direction of their length. If a piece of steel, heated to a proper degree for hardening, be plunged
into water, and suffered to remain there until it becomes cold, it is found by experience to be very liable
to crack or break, and in many cases it would be found too hard for the operations it was intended to
perform.
If the steel cracks or breaks, it is spoiled. In order, therefore, to fit it for use, should it happen not
to be broken in hardening. it is the common practice to heat the steel again, in order to reduce or lower
its temper, as it is technically called. The degree of heat to which it is now exposed determines the
future degree of hardness, or the temper, and this is indicated by a change of color upon the surface of
the steel. During this heating a succession of shades is produced, from a very pale straw-color to a
very deep blue. It is found, however, by long experience, that on plunging the steel into cold water,
and allowing it to remain there no longer than is sufficient for lowering the temperature of the steel
to the same degree as that to which a hard piece of steel must have been raised to temper it in the
common way, it not only produces the same degree of hardness in the steel, but, what is of much more
importance, almost entirely does away the risk or liability of its cracking or breaking. It is impossi-
ble to communicate by words, or to describe the criterion by which we can determine when the steel has
arrived at the proper degree of temperature after being plunged into cold water it can only be learned
by actual observation, as the workman must be guided entirely by the kind of hissing or singing noise
which the heated steel produces in the water while cooling. From the moment of its first being
plunged into the water the varying sound will be observed; and it is at a certain tone, before the
noise ceases, that the effect to be produced is known.
The only directions which can be given whereby the experimentalist can be benefited, are as fol-
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lows namely-to take a piece of steel which has already been hardened by remaining in the water till
cold, and by the common method of again heating it to let it be brought to the pale yellow or straw
color, which indicates the desired temper of the steel plate to be hardened. By the above process, as
soon as he discovers this color to be produced, to dip the steel into water and attend carefully to the
hissing, or as some call it a singing, which it occasions, he will then be better able, and with fewer ex-
periments, to judge of the precise time at which the steel should be taken out. It is not meant to be
understood that the temper indicated by a straw-color is that to which the steel plate, cylinder, or die,
should be ultimately reduced, because it would then be found too hard, but merely that the tempera-
ture which would produce that color is that by which the peculiar sound would be occasioned, when
the steel should be withdrawn from the water for the first time. Immediately on withdrawing it
from the water, the steel plate, cylinder, or die, must be laid upon, or held over a fire, and beated
uniformly until its temperature is raised to that degree at which tallow would be decomposed or, in
other words, until a smoke is perceived to arise from the surface of the steel plate, after having been
rubbed with tallow now the steel plate must then be again plunged into water, and kept there until
the sound becomes somewhat weaker than before. It is then to be taken out and heated a second
time, to the same degree, by the same rule of smoking tallow as before, and the third time plunged
into water, till the sound becomes again weaker than the last; exposed the third time to the fire as
before; and for the last time returned into the water and cooled. After it is cooled, clean the surface of
the steel plate, cylinder, or die, by heating it over the fire. The temper must be finally reduced by
bringing on a brown or such other lighter or darker shade of color as may best suit the quality of the
steel for the purpose to which it is to be applied."
The following is another improvement of Mr. Jacob Perkins' :-A cylinder of very soft or decarbon-
ized steel is made to roll, under a great pressure, backward and forward on the hardened engraved plate,
till the entire impression from the engraving is seen on the cylinder in alto-relievo. The cylinder is
then hardened and made to roll again backward and forward on a copper or soft steel plate, whereby
a perfect facsimile of the original is produced of equal sharpness.
The improved press, now generally used by steel and copper-plate printers, is also due to Mr. Perkins.
In short, he bears the same relation to steel engraving that Senefelder does to the lithographic
process.
Engraving on Stone, or Lithography-A modern invention, by means whereof impressions may be
taken from drawings made on stone. The merit of this discovery belongs to ALOYS SENEFELDER, a
musical performer of the theatre at Munich about the year 1800. The following are the principles on
which the art of lithography depends:-First, the facility with which calcareous stones imbibe water
second, the great disposition they have to adhere to resinous and oily substances; third, the affinity
between each other of oily and resinous substances, and the power they possess of repelling water or a
body moistened with water. Hence, when drawings are made on a polished surface of calcareous
stone with a resinous or oily medium, they are so adhesive that nothing short of mechanical means can
effect their separation from it, and whilst the other parts of the stone take up the water poured upon
them, the resinous or oily parts repel it. Lastly, when over a stone prepared in this manner a colored
oily or resinous substance is passed, it will adhere to the drawings made as above, and not to the
watery parts of the stone. The ink and chalk used in lithography are of a saponaceous quality
the former is prepared in Germany from a compound of tallow soap, pure white wax, a small quantity
of tallow, and a portion of lampblack, all boiled together, and when cool dissolved in distilled water.
The chalk for the crayons used in drawing on the stone is a composition consisting of the ingredients
above mentioned, but to it is added when boiling a small quantity of potash. After the drawing on
the stone has been executed and is perfectly dry, a very weak solution of vitriolic acid is poured upon
the stone, which not only takes up the alkali from the chalk or ink, as the case may be, leaving an inso-
luble substance behind it, but it lowers in a very small degree that part of the surface of the stone not
drawn upon, and prepares it for absorbing water with greater freedom. Weak gum water is then ap-
plied to the stone, to close its pores and keep it moist. The stone is now washed with water, and the
daubing ink applied with balls as in printing; after which it is passed in the usual way through the
press, the process of watering and daubing being applied for every impression.
There is a mode of transferring drawings made with the chemical ink on paper prepared with a
solution of size or gum tragacanth, which being laid on the stone and passed through the press leaves
the drawing on the stone, and the process above described for preparing the stone and taking the im-
pressions is carried into effect.
In Germany many engravings are made on stone with the burin, in the same way as on copper; but
the very great inferiority of these to copper engravings makes it improbable that this method will
ever come into general use.
Copper or steel plates may be transferred to stone and worked by power-presses; and from the les-
sened expense, it is now generally resorted to by publishers of maps where large quantities are re-
quired.
Perhaps one of the greatest advantages of the art of lithography is the extraordinary number of
copies that may be taken from a block. As many as 70,000 copies or prints have been taken from one
block, and the last of them nearly as good ns the first. Expedition is also gained, inasmuch as a fifth
more copies can be taken in the same time than from a copper-plate: and as regards economy, the ad-
vantage over every other species of engraving is very great.
Engracing on Silver and Gold-M. Poitevin, a Frenchman, has succeeded in producing plates, engraved
either in relief or in sunk lines, from which proofs may be taken. For the carrying out of this pro-
cess from two to three hours only are required.
The engraving is first exposed to the vapor of iodine, which becomes deposited upon the black
parts only. The iodized engraving is then applied, with slight pressure, to a plate of silver, or silvered
copper, polished in the same manner as daguerreotype plates. The black parts of the engraving,
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ENGRAVING ON WOOD.
which have taken up the iodine, part with it to the silver, which is converted into an iodide at those
parts opposite to the black parts of the design. The plate is then put in communication with the
negative pole of a small battery, and immersed in a saturated solution of sulphate of copper, con-
nected with the positive pole by means of a rod of platinum. The copper will only be deposited on
the non-iodized parts, corresponding to the white parts of the engraving, of which a perfect representa-
tion will thus be obtained;-the copper representing the white parts, and the iodized silver the black
parts. The plate must be allowed to remain in the bath for a very short time only; for, if left too
long, the whole plate would become covered with copper. The plate, after having received the deposit
of copper, must be carefully washed, and afterwards immersed in a solution of hyposulphite of soda,
to dissolve the iodide of silver, which represents the black parts; it is then well washed in distilled
water, and dried. The next operation is to heat a plate to a temperature sufficient to oxidize the
surface 01 the copper, which successively assumes different tints, the heating being stopped when a
dark brown color is obtained. It is then allowed to cool, and the exposed silver is amalgamated,-
the plate being slightly heated, to facilitate the operation. As the mercury will not combine with the
oxide of copper, a design is produced, of which the amalgamated parts represent the black, and the
parts of the plate covered with oxide of copper represent the white parts. The amalgamation being
complete, the plate is to be covered with three or our:thicknesses of gold leaf; and the mercury is
evaporated by heat, the gold only adhering to the black parta. The superfluous gold must then be
cleaned off with the scratch-brush; after which the oxide of copper is dissolved by a solution of nitrate
of silver, and the silver and copper underneath are attacked with dilute nitric acid. Those parts of
the design which are protected by the gold, not being attacked, correspond to the black parts of the
plate; the other parts corresponding to the white parts of the engraving, may be sunk to any required
depth. When this operation is completed the plate is finished, and may be printed from in the ordi-
nary method of printing from wood-cuta.
To obtain from the saine prints plates with sunk lines similar to the ordinary engraved copper-plates,
a plate of copper covered with gold is operated upon. On immersion in the sulphate of copper solu-
tion the parts corresponding to the white parts will become covered with copper. The iodine. or com-
pound of iodine, formed, is then to be removed by the hyposulphite, the layer of deposited copper is
oxidized, and the gold amalgamated, which may be removed by means of nitric acid,-the oxide of
copper being dissolved at the same time. In this instance the original surface of the plate corresponds
to the white parts of the print, and the sunk or engraved parts to the black parts, as in the ordinary
copper-plate engravings.
ENGRAVING ON WOOD. There are various modes for protecting the eyes when working by
lamp-light, but we are aware of only
one which both protects the eyes from
the light and the face from the heat of
the lamp. This consists in filling a large
transparent glass globe with clear wa-
ter, and placing it in such a manner
1571.
between the lamp and the workmen
that the light, after passing through
the globe, may fall directly on the
block. in the manner represented in
B
the Fig. 1571. The height of the
lamp can be regulated according to
the engraver's convenience, in conse-
quence of its being movable on the
upright piece of iron or other metal
which forms its support. The dotted
line shows the direction of the light
when the lamp is elevated to the height
here seen; by lowering the lamp a lit-
tle more, the dotted line would incline
more to a horizontal direction, and ena-
ble the engraver to sit at a greater dis-
tance. By the use of these globes one
lamp will suffice for three or four per-
sons, and each person have a clearer
and cooler light than if he had a lamp
without a globe solely to himself.
There are only four kinds of cutting
tools* necessary in wood engraving, namely gravers, tint-tools, gouges or scoopers, and flat tools or
chisels. Of each of these four kinds there are various sizes. Fig. 1572 shows the form of a graver that
is principally used for outlining or separating one figure from another. A is the back of the tool; B
the face; C the point; and D what is technically called
the belly. The horizontal dotted line C, 2, shows the
1572.
surface of the block. and the manner in which part of
A
B
2
the handle is cut off after the blade is inserted.t This
c
tool is very fine at the point, as the line which it cuts
D
A sharp-edged scraper, in shape something like 8 copper-plate engraver's burnisher, is used in the process of lowering
+ The handle, when received from the turner's, is perfectly circular at the rounded end; but after the blade is inscrted,
a segment is cut off at the lower part, as seen in Fig. 1572.
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ENGRAVING ON WOOD.
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ought to be 80 fine as not to be distinctly perceptible when the cut is printed, as the intention is
merely to form a termination or boundary to a series of lines running in another direction. Though
it is necessary that the point should be very fine, yet the blade ought not to be too thin, for then,
instead of cutting out a piece of the wood, the tool will merely make a delicate opening, which
would be likely to close as soon as the block should be exposed to the action of the press. When the
outline tool becomes too thin at the point the lower part should be rubbed on a hone, in order to reduce
the extreme fineness.
About eight or nine gravers of different sizes, beginning from the outline tool, are generally sufficient.
The blades differ little in shape, when first made, from those used by copper-plate engravers; but in
order to render them fit for the purpose of wood engraving, it is necessary to give the points their pecu-
liar form by rubbing them on a Turkey stone. In
1573.
Fig. 1573 are shown the faces and part of the
A
backs of nine gravers of different sizes; the lower
dotted line AC shows the extent to which the
points of such tools are sometimes ground down
by the engraver in order to render them broader.
When thus ground down the points are slightly
rounded, and do not remain straight as if cut off by
the dotted line A C. These tools are used for
nearly all kinds of work, except for series of parallel lines, technically called "tints." The width of the
line cut out, according to the thickness of the graver towards the point, is regulated by the pressure of
the engraver's hand.
Tint tools are chiefly used to cut parallel lines forming an even and uniform tint, such as is usually
seen in the representation of a clear sky in wood-cuts. They are thinner at the back, but deeper
at the side than gravers, and the angle of the face, at the point, is much more acute. About seven
or eight, of different degrees of fineness, are generally sufficient. Fig. 1574 will afford an idea of
the shape of the blades towards the point. The
1574.
handle of the tint tool is of the same form as that of
a graver. The figure marked A presents a side view
of the blade; the others marked B show the faces.
Some engravers never use a tint tool, but cut all
their lines with a graver. There is, however, great
uncertainty in cutting a series of parallel lines in
this manner, as the least inclination of the hand to
B
A
one side will cause the graver to increase the width
of the white line cut out, and undercut the raised one left, more than if in the same circumstances a tint
tool were used. This will be rendered more evident by a comparison of the points and faces of the
two different tools, Fig. 1575.
The tint tool, being very little thicker at B than at the point A, will
cause a very trifling difference in the width of a line in the event of a
A
1575.
wrong inclination, when compared with the inequality occasioned by
B
the unsteady direction of a graver, whose angle at the point is much
greater than that of a proper tint tool. Tint tools ought to be suffi-
ciently strong at the back to prevent their bending in the middle of the
blade when used, for with a weak tool of this kind the engraver can-
not properly guide the point, and hence freedom of execution is lost.
Tint tools that are rather thick in the back are to be preferred to such as are thin, not only from their
allowing of great steadiness in cutting, but from their leaving the raised lines thicker at the bottom,
and consequently more capable of sustaining the action of the press. A tint tool that is of the same
thickness both at the back and the lower part, cuts out the lines in such a manner that a
1576.
section of them appears as in Fig. 1576: the black raised lines from which the impression
is obtained being no thicker at their base than at the surface; while a section of the lines
cut by a tool that is thicker at the back than at the lower part appears as in Fig. 1577.
1577.
It is evident that lines of this kind having a better support at the base, are much less liable
than the former to be broken in printing.
Gouges of different sizes, Fig. 1578, from A the smallest to B the largest,
as here represented, are used for scooping out the wood towards the centre of
A
the block; while flat tools or chisels, of various sizes, are chiefly employed in
cutting away the wood towards the edges. Flat tools of the shape seen in figure
C are sometimes offered for sale by tool-makers, but they ought never to be
used for the projecting corners are very apt to cut under a line, and thus re-
1578.
move it entirely, causing great trouble to replace it by inserting new pieces
of wood.
A
The face of both gravers and tint tools ought to be kept rather long than
B
short; though if the point be ground too
fine, it will be very liable to break. When,
1'579.
as in Fig. 1579, the face is long-or,strictly
speaking, when the angle, formed by the
plane of the face and the lower line of
C
the blade, is comparatively acute-a line
is cut with much greater clearness than when the face is comparatively
obtuse, and the small shaving cut out turns gently over towards the hand. When, however, the face
of the tool approaches to the shape seen in Fig. 1580, the reverse happens; the small shaving is rather
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ENGRAVING ON WOOD.
ploughed out than cleanly cut out; and the force necessary to push the
1580.
tool forward frequently causes small pieces to fly out at each side of the
hollowed line, more especially if the wood be dry. The shaving also, in-
stead of turning aside over the face of the tool, turns over before the
point, as in Fig. 1580, and hinders the engraver from seeing that part of
the pencilled line which is directly under it. A short-faced tool of itself prevents the engraver from
distinctly seeing the point. When the face of a tool has become obtuse, it ought to be ground to a
proper form; for instance, from the shape of the figure A to that of B, Fig. 1581.
1581.
A.
B
Gravers and tint tools when first received from the maker are generally too hard,-a defect which
IS soon discovered by the point breaking off short as soon as it enters the wood. To remedy this, the
blade of the tool ought to be placed with its flat side above a piece of iron-a poker will do very well-
nearly red-hot. Directly it changes to a straw-color it is to be taken off the iron, and either dipped in
sweet oil or allowed to cool gradually. If removed from the iron while it is still of a straw-color, it
will have been softened no more than sufficient; but should it have acquired a purple tinge, it will have
been softened too much and instead of breaking at the point, as before, it will bend. A small grind-
stone is of great service in grinding down the faces of tools that have become obtuse. A Turkey stone,
though the operation requires more time, is however a very good substitute, as, besides reducing the
face, the tool receives a point at the same time. Though some engravers use only a Turkey stone for
sharpening their tools, yet a hone in addition is of great advantage. A graver that has received a final
polish on a hone cuts a clearer line than one which has only been sharpened on a Turkey stone: it also
cuts more pleasantly, gliding smoothly through the wood, if it be of good quality, without stirring a
particle on each side of the line.
The gravers and tint tools used for engraving on a plane surface are straight at the point, as are here
represented, Figs. 1582 and 1583; but for engraving on a block rendered concave in certain points by
lowering, it is necessary that the point should have a slight inclination upwards, as in Fig. 1582. The
1583.
1582.
dotted lines show the direction of the point used for plane-surface engraving. There is no difficulty in
getting a tool to descend on one side of a part hollowed out or lowered; but unless the point be slightly
inclined upwards, as is here shown, it is extremely difficult to make it ascend on the side opposite, with-
out getting too much hold, and thus producing a wider white line than was intended.
As the proper manner of holding the graver is one of the first things that a young wood-engraver is
taught, it is necessary to say a few words on the subject. Engravers on copper and steel, who have
much harder substances than wood to cut, hold the graver
with the fore-finger extended on the blade beyond the
1584.
thumb, Fig. 1584, 80 that by its pressure the point may be
pressed into the plate. As box-wood, however, is much
softer than copper or steel, and as it is seldom of per-
fectly equal hardness throughout, it is necessary to hold
the graver in a different manner, and employ the thumb
at once as a stay or rest for the blade, and as a check upon
the force exerted by the palm of the hand, the motion being chiefly directed by the fore-finger, as is
shown in Fig. 1585.
1585.
The thumb, with the end resting against the side of the block, in the manner above represented,
allows the blade to move back and forward with a slight degree of pressure against it, and in case of a
slip it is ever ready to check the graver's progress. This mode of resting the thumb against the edge
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ENVELOP MACHINERY.
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1586.
of the block is, however, only applicable when the cuts are so small as to allow of the graver, when
thus guided and controlled, to reach every part of the subject. When the cut is too large to admit of
this, the thumb then rests upon the surface of the block, as seen in Fig. 1586; still forming a stay to
the blade of the graver, and a check to its slip, as before.
ENVELOP MACHINERY, by M. Rémond. In earliest stages of the invention, the paper blanks
were cut out, and the subsequent folding performed entirely by hand; but the necessity of a prodigious
increase in the power of production, speedily led to the employment of mechanical means for the entire
manufacture. One of the first of these improvements was an improved paper-cutting machine, a plan
for cutting out the blanks. Many envelop-makers use this machine now; but others employ a hollow
cutting die, cutting through about 250 sheets of paper at once; but the cutter being made very thin. to
give an easy cut, generally springs under pressure, and the blanks thus become unequal in size, easily
detected when the folding operation comes into action.
As an example of the class of cutting-die employed, we have en
1587.
graved two views of it. Fig. 1587 is a sectional elevation of the die.
and Fig. 1588 a plan. It is simply a knife, shaped to the contour of
the envelop blank, A being the sharp edge. This is forced through
a thick pile of sheets by 14 convenient press, 80 as to produce blanks
agreeing in shape to the interior of the two lines in Fig. 1588. This
shape, it will be observed, is not one now in common use, but it
serves as an example of some of the attempts which have been made
1588.
to give additional security, and probably a greater appearance of
style. The cut pieces are gummed on one side, at the ends of each
flap; and when folded, as indicated by the dotted lines in the plan
of the cutter, the long narrow part adheres to one end of its counter-
part, forming the back, and the remaining pair of flaps fold down
upon it. This shape of envelop has, for many reasons, never come
into ordinary use.
In 1845 a folding machine for completing the envelops from the
blanks was invented by Mr. Edwin Hill, and Mr. Warren De la Rue,
jointly. and is now worked in the extensive establishment of Messrs. De la Rue, London. Its rate of
production is stated to be 42 folded envelops per minute; or, for a day's work of 10 hours, 25,200.
The blanks are laid by hand upon a table carrying a metal frame, the interior of which exactly corre-
sponds to the size and shape of the finished envelop; and immediately over this is a box or plunger,
which, fitting to the interior of the frame, is caused to descend upon the paper blank when laid over
it, thus creasing it on all the four sides, as will be understood on examining a partially-opened envelop;
the box then opens to admit of a partial folding. In this condition the blank has simply been creased,
and the four flaps stand up at right angles to the plane of the sheet. Before the creasing box is entirely
raised, two of a set of folders, placed one on each of the four sides of the frame, come forward and press
down the two flaps corresponding to their situation; and the remaining pair of folders come into action
to press their two flaps after the other portion of the plunger is raised. These movements complete
the envelop, by turning down the right angle flaps to the plane of the sheet, and the next step is to
remove them from the folding frame. For this purpose two finger-shaped projections of caoutchouc are
made use of; and, owing to the strong adhesion existing between this substance and paper, the folded
envelops are quickly removed as fast as they are produced. The twenty-two movements required in
folding each envelop are performed rapidly and noiselessly, principally by various adaptations of cams.
Prior to Messrs. Hill and De la Rue's invention, the only facilitation of manual labor in folding was
obtained by the use of a species of tool, which partially creased the blanks, leaving them to be turned
up and finished by band. Compared with "the results of machinery," the hand labor, although in
itself an astonishing instance of practical dexterity, is inordinately slow. Girls are always employed in
this work; and a first-rate hand can fold and gum for use from 3,000 to 3,500 per day, or from 5 to 6
per minute, the average performance being from 2,500 to 3,000. To arrive at this perfection, at least
six or eight months' practice are required.
By another comparative statement now before us, we find that, in unstamped envelops, hand labor,
6 per minute, 10 hours per day = 3,600; the work of one girl. Stamped envelops, hand labor, 4 1-6 -
per minute, 10 hours per day = 2,500, a day's work; the time being divided into 7 hours for folding and
gumming, and 3 for stamping.
77
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ENVELOP MACHINERY.
Fige. 1589 to 1597 exhibit, in very full detail, an improved folding machine, patented during the
present year, by M. Rémond. In this machine some ingenious appliances are introduced, whereby
atmospheric pressure is employed to facilitate the feeding in of the blanks to the folding apparatus and
the secondary folding action of the flaps in connection with the creasing plunger.
Fig. 1589 is a side elevation of the machine, partially in section. Fig. 1590 is a corresponding view
at right angles to Fig. 1589. Fig. 1591 is a vertical section of a portion of the machinery, taken at the
dotted line A B in Fig. 1589. Fig. 1592 is a horizontal view or plan of the folding table, with the
details of the apparatus for receiving the blanks preparatory to folding. Fig. 1593 is a transverse
section, taken at the dotted line CD in Fig. 1589. Fig. 1594 is a plan of the feeding-slide NN in Figs.
1589 and 1590. Figs. 1595, 1596, and 1597 are details of the guide apparatus for the several move-
ments on the main shaft A of the machine.
1595.
I
1596.
o
N
W
1589.
y
A
H
1597.
The arrangement of the mechanism is such, that a quantity of blanks of the required size being placed
on the feeding table, each will be taken up singly from the pile, and fed into the folding apparatus by
means of an instrument, in which, at proper intervals, a partial vacuum is formed, whereby each sheet
is sucked up against the surface of the fingers for conveyance to the folder.
The first step of the process of folding is accomplished similarly to the mode hitherto adopted, and
generally explained, in reference to Messrs. De la Rue's machine, that is, the flaps of the blanks are
bent to a right angle by the same means; but a novel arrangement is introduced for the performance
of the secondary fold. The bottom of the creasing frame or box is perforated, so that the passing back
of the plunger leaves the blank within the recess, with its four flaps standing upright: and here the
second application of the atmospheric action comes into play, for the purpose of giving the flaps a pre-
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ENVELOP MACHINERY.
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liminary inclination inwards, in order to fit them for receiving the flat folding pressure of the return
stroke of the plunger. To this end the sides of the folding box are perforated, SO as to allow streams of
atmospheric air to be forced against the outsides of the flaps; so that, on the descent of the plunger.
they will all be folded down at once, the interior and under surface of the plunger being suitably formed
to cause the flaps to succeed each other in their proper order. In addition to this, certain contrivances
are adapted for stamping the outer flaps with an embossed or perforated device, and also for gumming
the lowest flap as a fastening for the completed envelop.
A is the main driving shaft, which gives motion to the machine. It carries at one end a fast-and-loose
driving pulley, and at the other a fly-wheel, to assist in regulating the movement; and its intermediate
portion is fitted with seven cams, for communicating motion to the different working parts. B is the
folding box, or recess, in which the folding process is performed. It consists of four side pieces, at the
angles of which are projections C C, between which the blanks are successively fed, so that they may be
correctly placed, and held during the action of the plunger. D is the door or movable bottom of the
box, hinged at one end, so that when an envelop has been folded in the box, it may be discharged
below; it is perforated with numerous holes for the escape of the air, as the blank is forced down, and
is kept closed by means of a lever E, which is actuated at the proper intervals of time by means of the
cam F on the main shaft, giving motion to a slide G, of which there are seven, all alike in construction,
in connection with the same number of cams. The slide works between two fixed guiding surfaces H H.
as detailed in Figs. 1595 and 1596, and has at its upper end a small anti-friction roller, kept up in con-
tact with its actuating cam by the elastic tension of a band of vulcanized India-rubber. The lower end
of the slide presses on the tail of the
1590.
cranked lever E, the other end of which
rests against the under surface of the
movable door D, so that the latter is kept
closed during the proper portion of the
revolution of the main shaft. The feeding
action is accomplished by the exterior cam
K on the shaft, giving motion-as before
explained with regard to the cam F-to
its slide L, which is attached to the shorter
L
"
arm of the cranked lever M, the opposite
arm of which is jointed by connecting rods
to the feeder N. This instrument is car-
ried upon a slide, having dovetailed edges,
moving between fixed guiding dovetails
at O O. It consists of two hollow fingers
PP, each having an opening on the under
side; the interior of the fingers opening
into the hollow portion of the slide, shown
by dotted lines, allowing of a partial
g
vacuum being obtained within the fingers
when the exhaust movement comes into
use. A flexible tube Q, of vulcanized
India-rubber, is attached to the under side
of the slide, the opposite end being con-
nected with the bellows R, which receive
motion at the required intervals from the
a
cam S acting on the slide T in connection
with the bent lever U, carried by a pillar
at the back of the machine. The longer
end of this lever is jointed by a connect-
ing rod V to the front plate W of the
horizontal bellows running on guide spin-
dles X X. In this way, when the under
side of the fingers comes upon the top
of the pile of blanks at Y, the exhausting action is brought into play, and the top sheet is carried
over to the top of the box B for deposit, with its angles fitting the corner guide pieces, as in plan at
Fig. 1592. At the termination of the outward stroke of the bellows, the sheet is separated from them
by the action of a valve in the bellows, opening outward at the commencement of the return stroke.
The platform Y carrying the pile of blanks, is made to rise and fall to suit the feeding action, by a
mechanical arrangement worked from the cam Z. This cam actuates a slide a, from which an arm b
descends for connection with the long lever c at the bottom of the framing, the opposite end of which is
jointed to a projection on the vertical spindle d of the platform. To compensate for the continual
decrease in the height of the pile of blanks, so that the upper one may always come in contact with
the lifting fingers when the platform rises, an India-rubber spring e is added, its action being to keep
up the platform in contact with the fingers, when permitted to do 80 by the actuating cam. AN
every thing depends upon accuracy of set. it becomes of the first importance to place the blanks
in the exact position intended; and to facilitate this, four projecting arms, or guides ff, are formed
on the top of the platform, agreeing, as in the angle pieces of the folding box, with the angles of the flat
blanks.
As the blanks are fed into proper position, the folding plunger g comes into action. This is a hollow
rectangular metal frame, carried by a slide h. receiving motion from the cam k. It has in its interior a
set of three projections, which, in the secondary movement, act on the separate flaps, folding them all
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ENVELOP MACHINERY.
down at once, when they are held in the required inclined position by the atmospheric side currents,
as previously detailed. The inclined projections are essentially necessary, in order that the flaps may
be folded down in their proper relative positions; the projection 1 pressing on one of the side flaps,
causes it to be folded first; afterwards the projection m acts upon one of the ends, whilst the third, n,
carries down the opposite one, the final folding being completed by the under edges of the plunger,
which gives a sharp pressure to the initiatory fold of the
whole series. By suitably setting these projections, any
1598.
order may be given to the flaps-thus, if the two end ones
do not overlap each other, they may be folded down to-
gether by equal projections. The detailed figures, 1598
and 1599, exhibit two intermediate stages of the plunger's
folding action. Fig. 1598 is a longitudinal elevation of the
plunger and the top of the folding box in the position taken
up after the first action of the former, the side air passages
for inclining the flaps being at 000. Fig. 1599 is a longi-
tudinal section of the same parts, taken just as the plunger
is about to descend in its secondary movement to give the
completing fold.
The necessary atmospheric side pressure on the flaps is
obtained from the inclined air-pump p, the piston of which
1599.
is driven by a crank pin on the fly-wheel; and a tube q
conveys the forced air from the bottom of the pump to a
hollow channel passing all round the edges of the folding
box, as dotted in the plan, Fig. 1592, whence the orifices
already pointed out, open inwards to the box. For the
application of gum, or other cementing fluid, to the lowest
flap, to secure the three stationary ones, a fountain is placed
at r, from the bottom of which two tubes 8 8 branch out to
the two flat tubular receptacles tt inclosed in a vessel u,
the supply being regulated by a stop-cock before the junc-
tion of the two supply branches. The gumming action is
performed by pieces of sponge placed in the upper ends
of the flat tubes t, which, standing slightly above their upper edges, the presser v descending just before
the plunger, presses the edges of the lowest flap upon the sponge, as clearly illustrated in the plan view.
This presser receives its motion from the cam 10 acting on the slide x, to which the presser is attached.
If it is intended to stamp or emboss the outer flap with an embossed of perforated device, dies are
applied as at yz. The die y being attached to a slide 1, acted on by the external cam 2, the stamping
action takes place just before the descent of the plunger.
1502.
1591.
и
m
/
72
B
D
This machine produces easily 60 envelops per minute, or 36,000 per day, completed, gummed, and
stamped, and might probably be worked faster. As at present practised in other modes of production,
the folding. gumming, and stamping are all separate processes; and as, at each of these operations,
every single envelop must be separately handled, we may form a tolerable conception of the economy
gained by the use of M. Rémond's machine, as the most improved contrivance of earlier date saves no
more than one-third of the manual labor. The isolation of the different stages of manufacture, conse-
quent upon the employment of manual labor, adds immensely to the cost of production, the loss mainly
arising from the mere removals from one process to another. In hand-stamping, a child will perhaps
get through 8,000 or 9,000 per day and then there must be an assistant to turn the tops where the
stamp has been placed, and count them into parcels.
Since the first anticipations of the value of the envelop for general consumption, many modifications
have been introduced. In 1844, Mr. Wilson, the inventor of the cutting machine, hit upon the ingeniously
simple mode of economizing the paper in cutting out the blanks, by cutting the original web of paper
diagonally across its width. Formerly, when the web was divided longitudinally, and then by trans-
verse cuts at right angles, the rectangular sheet thus formed, when cut up into diamond pieces for
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ETCHING.
613
envelops, suffered considerable loss in the reduction. By Mr. Wilson's plan this was avoided, as the
transverse cuts being all made diagonally, each blank fitted exactly to its neighbor, and this source of
loss was removed. In 1846, again, Mr. Charles Chinnock obtained a patent for some contrivances for
the obtainment of greater security of enclosure, by applying the ordinary postage stamp, or other
adhesive labels, so as to become a fastener for the edges of the paper forming the envelop. In one of
his arrangements, a small hole, somewhat less than the area of a postage stamp, is punched at the right-
hand corner of the address side, so that, when the stamp is put on, it adheres not only to the edges of
the hole, but also to the turned-in edge produced in the end fold of the envelop, as well as partially to
the enclosed note. Thus the enclosure cannot be removed without leaving detective marks. According
to another mode, the patentee punches holes of various sizes through the parts of the envelop where the
seal is placed-in some cases placing a bit of blotting-paper beneath, this being for the purpose of
securing the whole by the seal. In another arrangement, the envelop is the same shape as that now
generally used, having four triangular flaps, meeting in the centre for the seal. In the ends of three
of these flaps are small holes, each one a little different in size, so that when folded the smallest hole
is the lowest, and the largest the third in the layers, whilst the fourth is blank, the wax below
which not only secures all the flaps, but adheres also to the enclosure. When a piece of blotting-paper
is placed below the holes, as in another modification, any attempt to open the letter would involve a
tear.
1593.
1594.
DC
N
The ordinary four-cornered envelop, fitted to form what M. Rémond calls the " Detector," appears to
answer all the requisites of security and elegance. The sealing-flap is embossed with some device, the
centre of which is perforated in any ornamental way, and a colored wafer is placed beneath it, showing
through the perforations like a colored device. When this is fastened in the usual way, a very slight
examination serves to show whether or not it has been tampered with. If the wafer is used, and hot
water or steam has been employed to soften it, its brilliancy will have entirely disappeared and if
attempted to be cut through, its substance is 80 thin, that, either wet or dry, the chances are, that the
minute integuments of the star, or other device, will be broken or disarranged. This species of seal
is besides ornamental, and for general purposes may supersede the now common plan of color-
stamping.
The only American machine in practical use is one secretly used by Bell & Gould, Nassau-street, N. Y.
We are unable to give any details respecting it.
ETCHING. The entire apparatus is contained in a box not larger than a music-book. They consist
of copper-plates, &c., etching-needles, hand-rest, etching-ground, dabber, oil-rubber, rottenstone, smo-
king-taper, engraver's-shade, bordering-wax, stopping-out varnish, tracing-paper, aquafortis, &c.
Ground-The ground is composed of asphaltum, Burgundy-pitch, and beeswax. Take equal por-
tions of the above-named materials, place them in an earthen pipkin in an oven, and melt them. The
mass must be kept stirred until well incorporated any small piece of wood will answer this purpose.
When well mixed, it must be poured into a basin of cold water, and when nearly cold should be pressed
and rolled with the hand, that all the water may be discharged, then made into a ball. Procure a
piece of worn silk, but be careful it is without holes, double it, place the ball therein, and tie up the
ends with packthread, taking care that the double silk reaches well over the ball. When tied tight,
cut off the overplus silk, and let the knot remain for a hand-hold. Be sure that the silk is tight over
the ball.
Dabber.-Take another piece of silk, twice the size of the last, double it, place in it a ball of coarse
wool well picked out, about the size of a small apple, tie it up in the same way as the ball for the
ground, and it is ready for use.
Oil-rubber.-The next thing necessary is an oil-rubber, which is simply a strip of woollen cloth,
about two inches wide, rolled up tight, and bound over with packthread or thin tape. With a sharp
knife cut off one end, avoiding the string so that the surface may be quite flat. This is used for taking
out stains or polishing the plate.
Rot'enstone.-Procure a piece of fine flannel, rather less than the silk which covers the etching
ground ball, double it, place on it a small quantity of rottenstone in powder, which tie up in a bag. A
small portion of fine whitening in the lump should be kept at hand for the sake of cleanliness any
small box will answer this purpose.
Smoking-taper.-Procure a wax taper, uncoil it by degrees before the fire until it is all equally
pliant: double it up in about six lengths, give it one twist while warm, and turn it a few times before
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the fire, that the pieces of taper may adhere to each other melt the wax at one end, so that the wick
is exposed; see that all the cotton ends will light freely: care should be taken to extinguish the cotton,
or it will revive with the least draught, and may become dangerous.
Bordering-waz.-This may be obtained ready made, but engravers make it to their own liking. The
component parts are three ounces of resin, two ounces of beeswax, and such a quantity of sweet-oil as
will soften the mixture to your fancy. Procure an earthen pipkin, place in the bottom a small quantity
of sweet oil, (half an ounce or more,) add your resin and beeswax, broken in small pieces; when melted.
work the ingredients well together with a stick until thoroughly incorporated, then pour into a basin of
cold water; as it gets cold, work it well with the hands by pulling out into lengths and doubling it to-
gether again the more it is worked the better it will be for use. Should it turn out brittle, return
it broken to the pipkin, and add more oil; work it well together as before; pour it into water, and
work it again with your hands.
Engraver's-shade.-The next thing required is a shade, which can be made of wire. Bend it to a
half-circle, bind it together with waxed string, lay it on tissue paper, cut away all but half an inch
round the wire, cover that half inch with paste, and turn it over the wire; when dry, the shade
is complete. Fasten a light string to the centre of the half-circle, and suspend it from the window-
latch when in use. This shade must be placed in a forward position, sloping before your plate, and the
white light it produces will enable you to see the lines made by your etching-needle. It is now the
real amusement begins. You can work any time you please at the plate, and lay aside without injury
to it.
Hand-rest.-Any flat and thin piece of wood will answer this purpose, which is merely to keep the
hand clear of the plate whilst at work.
Stopping-out Varnish.-Turpentine varnish is superior, for several reasons, to Brunswick black.
Turpentine Varnish.-Break small bits of resin into a vial, cover it over with spirits of turpentine
to about twice the height of the resin. Place the bottle in a small saucepan of water on the hob, near
enough to the fire to make and keep the water hot; a cork may be lightly placed in the mouth of the
bottle, as the mixture will require to be shaken occasionally.
A small portion of this mixture should be poured into a small pot, with a little lampblack added, to
give it color, and well incorporated. This last is necessary to prevent lumps; it may be done by work-
ing the mixture well together with the camel-hair pencil. You have now a good stopping-out varnish.
With this varnish go over the border or margin of your plate: do this when about to put it away, and
the varnish will become hard by being left a night to set.
When inclined to put your plate through the process of biting-in, again go over the margin, using the
same brush and mixture. You can always work it up by adding a little turpentine. When it is set
80 hard that you can place the finger on it without adherence, it is time to make up your wall or border
of wax to hold the aquafortis.
Aquafortis.Provide yourself with three half-pint bottles having glass stoppers, and two pint
earthen jugs with spouts. Then obtain at the chemist's half a pound of nitric acid in a bottle No. 1.
Pour into bottle No. 2 rather less than the fourth of. the nitre pour the bottle three parts full of water
with a slow action pass it into one of your pint jugs, and back again to the bottle, to unite it well. In
bottle No. 3 put one half of the remaining nitre; water it as before; see that the nitric acid in bottle
No. 1 is well stoppered, and cover it with a piece of old glove.
Tracing, and Tracing-paper.-Tracing-paper of various qualities may be purchased at any depôt of
arts. But, in case of necessity, very good tracing-paper may be made by saturating with a camel-hair
pencil the finest tissue paper with the following mixture :-Half an ounce of the balsam of Canada to
one ounce of the spirits of turpentine, shaken well together in a two-ounce bottle: it requires no heat.
When covered with the mixture, hang the paper on a line to dry then wash in like manner the other
side.
Place your drawing on the tracing-board, (a piece of soft planed deal,) over it lay the tracing-paper,
fasten down with the brass-headed points, not through the drawing, but close to it, so that the pressure
of the brass head secures both the drawing and tracing-paper from moving. Go carefully over all the
lines of your drawing with an H-pencil, occasionally placing a piece of white paper between the
drawing and the tracing-paper, to ascertain that you have not neglected any part of the lines on the
drawing.
Transferring-paper.-This is very easily made, as follows:-Take half a sheet of very fine bank
post paper, lay it on a clean place and rub it well with the scrapings of red chalk a small bit of
sponge is good for this purpose. Apply the chalk until the paper is all of one color, then, with a piece
of clean old muslin, rub the greater part of the color from the surface. The color may be renewed
occasionally as the marking becomes faint.
Testing the Ground-Heat one corner of your plate, and rub over it the ground, in a thin and even
surface. Next apply your dabber, to make a yet more equal distribution of the ground. When cold,
mark over it with rather a blunt needle, (No. 3.) Should the ground be brittle, and crack with the
passage of the needle, add to it more beeswax; should it drag with the needle. more asphaltum: the
ground will easily melt again. When a ball is made to your satisfaction it will last a long time. The
weather has considerable effect on the mixture, but the quality of the ingredients more, so that it is
advisable to get the ground as perfect as you can while you have the melting-pot in use.
Heating the plate for ground-You must have a small hand-vice with a haft of wood to resist the
passage of heat to the hand. If your plate is stained or discolored, the mark must be removed with
the oil-rubber, with a little rottenstone and oil, polished off with a bit of old muslin powdered with
whitening. Be careful that no dust remains on the plate. Screw the vice on the long side of your
copper-plate with a slight hold, covering the part grasped by the jaws of the vice with a small piece
of paper, to prevent injury to the surface.
Heating may be performed by burning paper under the back of the plate; but a stove or clear fire
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is much the preferable mode. Be careful not to overheat your plate. If the surface becomes dis-
colored the plate is over hot as a test, turn it over and spit on the back; if the moisture jumps off,
the plate is sufficiently hot should it hiss and remain on the plate, more heat must be obtained.
A piece of sailcloth, rather larger than the plate, should be warmed by laying it before the fire
during the heating process ; place it on the table, and lay upon it the plate, retaining the vice. Now
pass your ball of ground over it backwards and forwards until the plate is covered, spreading the
ground as evenly and thinly as possible. Then use your dabber with a quick action, pressing it down
and plucking it up. If the ground does not distribute itself easily burn paper under it, as before, until
it shines all over, being cautious that the ashes of the paper do not settle on the surface; dab on again,
decreasing the pressure but not the speed of action, until the surface is all over alike.
Smoking the plate-Have your taper ready, and a single taper or candle to take the light from the
surface of your plate being perfectly covered, it may be as well to renew the heat in your plate by a
paper burnt under the back until the surface shines, taking the same precautions as before.
Hold the plate up in your left hand, with the face downward; light your smoking-taper, at the same
time, having all the wicks burning, pass it rather quickly round the margin, and by degrees towards
the centre, using a fluttering action with the hand ; smoke on until the whole surface is of a dark color,
keeping the taper at such a distance from the plate that the burning cotton may have no chance of
touching it, although the flame spreads over it when the surface is all black alike, and no sooty marks
are to be seen on the working part of the plate, the ground is fit for use. Take the plate, face down-
ward, to some convenient place, and pour cold water over the back, holding the plate in a sloping
position, the vice up, Fig. 1600. This last process produces a stronger and harder surface than could
be obtained if the plate were left gradually to cool. Now place the plate face downwards, supported
on one side by the screw of the vice, Fig. 1601. Clean the smoke from the back, and let it remain
until quite cold.
1606.
1602,
1605.
1601.
1603.
1600.
1604.
As Figs. 1600 to 1611 consist of examples of the etching, biting-in with the acid, &c., I shall take advan-
tage of it to exemplify the manual craft of laying the ground, smoking, &c. Some difficulty may be
found in laying the first ground with success; but having managed one well, you may be sure for the
future.
Transferring.-If you have not an etching-board place your copper-plate on a thick piece of brown
paper, larger than the plate make two ribe of the same paper, doubled four or more times, and about
an inch wide place them at each end of your plate on the brown paper, and fasten them with sealing-
wax: these ribe serve as shoulders for the rest to lay on, which will prevent your hand from touching
the work.
You may now cut your tracing-paper to the size of your plate, having ruled your margin line, if one
is required. Place your tracing reversed, that is, the pencil side to the plate. Fix it with bits of soft
wax round the border, leaving open the bottom to admit the transferring-paper, which introduces the
chalk side next to the plate: the upper side of the paper must be kept clean, that you may see the
pencil lines on your tracing-paper. Next with an H H pencil, sharp and short in the cut, go over all
the lines of your tracing with rather an upright hand, that you may be able to make strong pressure
the upper side of your tracing-paper, not being marked with pencil, will show whether you have
gone over the whole of the lines with the pencil on the upper side; look sideways at your work, and
the black-lead mark will be perceptible. Before you advance far in your transfer, lift up the bottom
of your tracing to ascertain if the lines are of sufficient strength if not, apply more red chalk to your
transfer-paper. When you think the transfer is completed, do not take off the whole of your paper,
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but allow the part affixed by the top spots of wax to remain. You can then lift up the whole of
the work, and if any part of it has been neglected the tracing can again be laid down, and the omis-
sion rectified.
Etching.-You must begin with needle No. 1 (the fine point) and go carefully over the outline, not
making much impression on the copper, but sufficient to remove the ground with the same point go
over all the lighter parts, increasing the pressure, so that a slight indentation may be made on the plate.
No. 2 point may now be used to go over the lighter shade with increased weight of hand. No. 2
point will answer for the darker shades by making the lines nearer together and increasing the pres-
sure. Interline parts that require extra color with No. 1 point: the etching may be worked at for a
considerable time by interlining and dotting.
Should you by accident or mistake make any marks you wish to expunge, dip a pointed camel-hair
pencil into the turpentine bottle, and with its point work up some of the ground on the margin of the
plate, and therewith stop out the objectionable marks. When set it will resist the aquafortia.
Bordering the plate.-In cold weather the wax will be too hard to be rolled out with the hand, it
must then be placed in moderately warm water until it becomes pliable; then pull and roll it out to
about the thickness of a small walking-stick slightly grease the point of the thumb and two fore-
fingers with deer or mutton fat, press the roll of wax flat as you place it on the border of your plate,
with the edge to the varnish, taking great care that the bordering-wax does not go off the varnish.
At what you intend to be the darkest corner of your plate pinch out the wax broader, that the height
of the wall may increase to that corner where the spout is to be formed with the wax, to prevent spill-
ing the aquafortis in pouring it off.
Biting-in.-Lay your plate flat on a piece of sailcloth larger than the plate, as a protection from any
splashings that may be made. Place the spout of your plate in front for the convenience of pouring
off. One of your jugs being filled with water, pour it over the plate to prove if there is any leakage
in your border; should you find any, pour off the water let the plate dry, particularly in the defective
part; then press down the outer edge of the wax with a piece of stick.
Lay by the side of your plate two or three wedges, (small pieces of firewood,) to be,used for tilting
the plate should the acid not lay even.
It would be worse than useless to prescribe rules for the proportions of water to be used to the
nitric acid, as that will entirely depend on the strength of the acid.
Having proved that your border is sound, pour off the water then cover the surface of the plate
with the aquafortis from No. 2 bottle. If in the course of half a minute the etching on your plate
should assume a light-gray coating the mixture will do; but if it should throw up bubbles it is over
strong, and more water must be added, but not on the plate. The mixture must be placed in the jug,
then in the bottle, and afterwards returned to the plate. Should the lines on the plate remain as bright
copper after the acid has been on half a minute, it is not strong enough, and some aquafortis out of
bottle No. 3 must be added.
Having mixed your aquafortis 80 that the lines do not produce foam, but continue a gray frosty ap-
pearance, the process is going on well. The power of biting-in correctly must depend on the experience
you have of your acid.
With a soft camel-hair pencil lightly remove the frosty appearance, taking care that the quill does
not touch the ground.
Should any part of the ground be breaking up, that is, the lines becoming united, pour off your acid
carefully into the jug. Lay the plate again on the flat, and cover it with water from the other jug,
moving it gently with the camel-hair pencil, which should be placed in the water-jug when taken from
the acid, or it will soon become useless.
The wash-water from the plate must be thrown away. The first biting now is supposed to be com-
pleted, therefore set the plate up endways to dry.
Second biting.-When the plate is perfectly dry, take off with your scraper a spot of ground in the
lighter part, to ascertain if the acid has made sufficient indentation. If it has, work up your stopping-
out varnish with a camel hair pencil, and with it cover all the parts you intend to remain light you
must elevate your rest so that you do not press the border-wax.
When the stopping-out varnish is dry, which may be ascertained by placing your finger on it and
finding that it does not stick, put on the same aquafortis (bottle No. 2) and let it remain until you ob-
serve the ground giving way then pour off the acid, and wash well as before. Put the plate to drain.
Should it be required, more biting may be performed, and the process is the same.
Cleaning off.-Now comes the least agreeable part of the process. Great care must be taken that
the plate is perfectly dry if it be not it may be placed before the fire, but not close enough to melt the
wax. Having carefully wiped the sailcloth, lay the plate a little more than half way upon it, but 80
that the balance remains to the table. Apply a lighted taper or a folded paper match progressively
under the wax; pull up the wax as the warmth proceeds; you will find that the slightest warmth
answers the purpose. By removing the wax with a knife you are liable to injure the margin, an evil
which gives much trouble to remedy. This being the most unpleasant process of engraving, it may
be as well to use old gloves if any of the wax should adhere to the plate, to remove it use a bit of
deal firewood cut in the shape of a chisel. Now fix your vice on the same end, and place as you did
when laying on the ground. Rub the plate over with a bit of rush candle, using the side, (taking care
to cover every part have some old soft rags ready; hold the plate up by the vice heat the back
with burning paper as before, until the ground varnish and tallow are melted. Rub off with a soft
rag. Should any smut remain, apply a little turpentine; withdraw the vice and wash the spot with
turpentine. Rub the plate front, back, and sides, with the rag.
Dab the plate with your bag of rottenstone; pour on it a little sweet-oil and with your oil-rubber
polish the plate with up and down strokes, using considerable pressure wipe the plate quite clean, and
polish off with fine whiting.
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Should you have succeeded in biting-in well, the plate is fit for the printer.
Dry point-Should your work have 80 far succeeded as to require but little improvement, the dry
point may next be used. For this purpose the needle No. 3, well pointed, (as indenture must be made
by pressure of the hand,) may be employed. For interlining the parts which are too weak, and uni-
ting lines neglected in the etching, the dry point will be sufficient; but as the pressure will leave a
projection or burr on the plate, it must be carefully removed by the sharp scraper should your plate
require more than the dry point can accomplish, recourse must be had to re-biting.
Re-biting.-Heat your plate as before, but make one corner (the one with the least work in it) hotter
than the other part.
Rub your ground on the hot corner, and with the dabber take the ground therefrom, and dab quickly
over the other part until the whole surface is covered. Prior to laying the ground the plate should be
polished with whiting, using a piece of old muslin folded in the shape of a dabber, which will fill
the etched lines, and prevent the new-laid ground from entering.
All the parts but those wanting more color must be stopped out as before; again the border-wax
must be used. Next follow with acid the same process.
Re-etching.-This is the most certain method of finishing the plate. The ground must be laid as
in the first instance, but using a greater body, and with the dabber rubbing it well into the lines, taking
care that no whiting remains in the etching marks; for this process the plate should be merely washed
with turpentine; a slight extra warmth and good dabbing will render the ground acid proof. The
smoking is here dispensed with
Set up your shade, and work at the plate as in the first instance. Now use No. 3 point, (sharp,) and
interline the parts you wish darker and where you want greater strength, crossing the lines, not in
direct angles, but lozenge ways.
The plate, cleaned off as before directed, receiving a light oil rubbing with a little rottenstone, and
washed off with turpentine, may now be sent to the printer's and a proof obtained.
By repeating the re-etching your plate may be worked up to the color of a line engraving.
In some of the darker parts a graver or lozenge tool may be used; but as it is rather dangerous in
the hands of the uninitiated, perhaps it may be best to do without it, as it is apt to slip and make
deep lines where none are wanted. Re-biting will produce any extra color that may be wanted with
little more trouble, and certainly with less danger.
General instructions-The following directions may be rather prolix, but will relieve beginners
from much trouble, and enable them to avoid many accidents to which engravers are liable.
1st. When using the acid, slightly grease that part of the hand likely to come in contact with it, as
a preventive to its making stains, which are not easily eradicated.
2d. When your border-wax has done its duty have it well washed in cold water; then warmed be-
fore the fire; pulled out and pressed together again, as the more frequently that is done the more
flexible the wax will be for future use.
3d. As your aquafortis will become reduced in strength by exposure to the air, it becomes necessary
to add a portion of No. 3 bottle to that of No. 2; and a small quantity of No. 1 bottle to No. 3: No. 1
bottle being the undilute acid.
4th. When making a point to your etching-needle work the point round, as, should there be any flat side
to the point, it will bite the copper and prevent the freedom of hand required to give spirit to the etching.
5th. With your burnisher you may soften down any part of your etching that appears harsh or
crude, by gently passing it over the parts to be reduced in color.
6th. Having your shade before you, which must be between you and the light, you will be enabled
to see the marks of the burnisher fine charcoal and oil will remove them, and the oil-rubber will clear
away the charcoal marks. The charcoal can be obtained at any coppersmiths or plate-printers.
7th. If your burnisher is good at first it never requires alteration. The scraper must be occasionally
sharpened.
Soft ground-Take half a ball of hard ground, (mixed as described under the head Etching-ground
to that add a piece of mutton-suet. Melt them well together, observing that the mixture must be
thoroughly incorporated; then pour into cold water, and use it as before directed.
Laying the ground-The process is exactly the same as in laying the etching-ground, with this differ-
ence, that the plate does not require 80 great a heat.
Smoke the plate the same as in laying etching-ground. The ground must be spread as thinly as it
possibly can, to cover the plate and bear smoking. The surface of the plate must be alike all over, and
quite bright or shining. If any part but the edges appear sooty, it must be cleared off, and the plate
polished, as described for etching, and laid again. You may by chance make a good ground at the first
melting, but that can scarcely be expected.
It may be as well to test the quality of your mixture before you lay a whole ground. To this end,
heat a small portion of your plate; lay some of the ground; smoke it; and let it get quite cold. Obtain
some of the finest tissue-paper,-not fine from thinness, but from its even texture. Place a piece of the
paper on the patch of ground laid, and with a fine-pointed H pencil make a slight sketch:-a bit of
foliage for instance; the paper should slightly stick to the plate: when carefully raised by the two
bottom corners, the back of it should clearly show every line made on its surface, only darker.
Should the sketch on the copper have a grainy appearance,-that is, look as if it was dotted all over,
the mixture of ground will do. Should the ground adhere to the paper, like marks with pen and ink,
the ground must be melted with an addition of hard ground; and if even the most tender marks of the
pencil do not pull the ground from the plate, the ground must be remelted, and 80 with one or the
other, as the ground may require, until it is fit for work.
As the season has great effect on this ground, the one that will answer for summer will not do for
winter, so it may be as well to make or procure two or three sorts of mixtures, and number them
according to their several degrees of hardness.
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Having succeeded in mixing your ground, take a piece of tissue-paper twice the size of your plate.
Place the plate in the centre, and with a black-lead pencil draw a line all round it. Make the same mark
on the other side; then lay the ground as before described. When cold, wipe the back and edges before
you take off the hand-vice. This ground being very tender, care must be taken not to touch the face of
the plate.
Upon the square marked on the paper your drawing is to be made. If you intend to copy the sub-
ject, you must go through the same process as in transferring for the hard-ground etching; only, instead
of transferring the red lines on the plate, they must be made within the square marked on the paper.
Take care that your tracing is reversed.
If you intend making your drawing on the plate without copy, you must lightly make your design on
the square marked with fine-pointed red chalk. Should the subject be figures, every thing must be
drawn, as it were, left-handed or reversed.
Fold a clean silk handkerchief in four, lay it flat and smooth on the table, place on it the paper with
the chalk sketch downwards. Now, with great tenderness, lay the plate face down, exactly on the
square mark of the paper; fold over the back the overplus paper, and fix the sides with four thin spots
of sealing-wax near the corners: be sure you do not move the plate on the silk. Take your plate care-
fully up, and place it for work. Use a rest as in etching, and a hard pencil, H H, on the places you wish
to be dark.
There is one drawback to the pleasure of soft-ground engraving you must finish what you begin the
same day the mechanical part of the work may be delayed. Your drawing finished, pull up your
paper by the two bottom corners.
Varnish the border down the same as in etching. The acid used must be much stronger; the border-
wax higher and broader in the spout, as you may perhaps have to pour off suddenly.
Biting-in.In biting-in the signal to pour off your acid is, when you perceive the ground breaking
up,-that is, coming up in patches.
During the biting-in the soft camel-hair pencil may be used, but very tenderly. Wash well off with
cold water, and place it to dry. For cleaning, see Etching, (supra.)
Should the plate require more finishing, have recourse to the hard ground without smoking.
1608.
1609.
1607.
Aqua-tinta engraving.-In this we have another variety of entertaining engraving; one, moreover,
which, unlike the last, is still much practised by professional engravers. It forms the ground-work of
many of the best modern prints, and is generally resorted to where the object is to produce a plate, the
impressions from which are to be colored. It will at once be recognized by its similarity to an Indian
Ink or Sepia Drawing; for in working the plate at press, black and brown inks are used indifferently, as
the artist or publisher may direct. Resin forms the ground in this method of engraving.
Without further remark, we proceed to a description of the materials and the mode of employing
them.
Aqua-tint ground-Break some of the best white resin into pieces, sufficiently small to go into the
mouth of the bottle used. Fill the bottle up, or nearly so, with spirits of wine. This must be occa-
sionally shaken, until the resin is dissolved. The bottles must have corks, not glass stoppers. Have
two other bottles ready; mark the bottles 1, 2, 3. No. 1 is the bottle in which the resin is placed.
Pour from the mixture No. 1 into No. 2 one-third; fill this bottle nearly with spirits of wine. Pour into
No. 3 bottle rather less of the mixture from No. 1, and nearly fill it with spirits of wine. These bottles
must be occasionally shaken, and their contents allowed to settle well before use. The contents of the
three bottles must be so mixed that they are one under the other in strength, as the size of the grain to
be laid on the plate depends on the quantity of resin each mixture contains. The more of resin the
larger the grain.
The spirit must be entirely free from water.
To test the spirit.-Place a small quantity of gunpowder in a silver spoon; pour over it some of the
spirit; light the spirit, and let it burn down to the powder. If the powder takes fire and explodes, the
spirit is good, and fit for use. If it should remain in the bottom of the spoon black and wet, the spirit
has been adulterated with water, and is not fit for the purpose.
Trial of aqua-tinta ground-Have a tin trough about two inches wide and rather longer than your
plate, with a convenient spout at one end; the trough is to act as a receiver of the spirit when poured
over the plate; the spout to return it to the bottle.
Laying the ground-Polish the plate well, as before directed. Place it on a slight slope, the tin
trough under the lower edge to receive the spare mixture. As a trial of your ground, pour the liquid
from each bottle, and make a small patch in different places at the bottom of your plate. When the
liquid has run off to your tin trough lay the plate flat, and with a piece of rag wipe the lower edge.
Take a magnifying-glass and look at the grains deposited on the copper.
Having poured the spirit from the trough to bottle No. 1, make choice of the grain most likely to suit
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your work, if indeed either of the three should; if not, you must mix the large grain and the small
together until it does, letting the mixture settle well before it is used. When you have made one
bottle of ground to suit your purpose, make a memorandum of the circumstance upon the bottle.
Having removed your trial spots, polish the plate well, and place it as directed for trial, with the side
you intend for the foreground next to the tin trough. Pour the mixture along the top of the plate, from
one end to the other, until the whole of the surface is covered. As soon as the spirit has run into the
tin, lay the plate flat: the sooner it is laid flat the rounder will be the setting of the grain: the longer
the plate remains on the slope, the more elongated the deposit of resin will become, which, for some
sort of work, will answer better than round-such as broken rock, water-falls, &c
In most cases it is advisable to make a very fine etching of the subject intended to be placed on the
plate prior to laying the aqua-tinta ground; in the end it will save time. The etching must be very light,
otherwise the aqua-tinta ground will hang round the lines and form a ray of light. Should the etching
be strong, it will require being filled up with wax, and polished off before laying the ground. Engravers
send the plate to the printer's, and have it filled up with ink, which is much the best method, where it
can be resorted to. If obliged to use wax, the plate must be heated rather above what is required for
the etching-ground, the surface wiped off, and polished with the soft part of the hand slightly rubbed
with whiting.
Having laid the ground to your satisfaction, the next pro-
1610.
ceeding is stopping out the lights.
Stopping out the lights.-Place on the left side a small
looking-glass in a stooping forward position lay before it
the drawing intended to be worked from, with the base or
foreground towards the bottom of the glass; you will then
see the subject reversed in the glass, which will enable you
to copy with greater freedom.
Go over the margin as directed under the head Etching.
For this a camel-hair pencil, and the same pot of varnish,
with a little more lamp-black added, and well worked to-
gether, should be used. Stop out all the white lights you
observe in the drawing. By the time you have done this the
varnish on the margm will be dry or set; if not, the plate
must remain until it is.
Then go over the margin again with the same varnish, and
let that set hard.
Now place up your border-wax as before directed, making
the spout rather larger, that you may be enabled to pour off
the acid quickly, if necessary.
Use the same aquafortis as for etching, but the strength
somewhat increased, as it will have to remain on the plate
a much shorter time.
Lay your plate an inch or so over the front of the
table, with the piece of sailcloth underneath, having small
wedges of wood ready to be used should the acid not float
evenly.
1611.
Put on the acid rather quickly; running it from the bottle
to the jug, then on the plate; the other jug, having been
filled with cold water, should be kept ready for washing
off. When the acid has entirely covered the plate, the sur-
face should immediately assume a frosty appearance, but not
come up in bladders. Little more than a minute may be
enough for the acid to remain on the plate; pour it into the
jug as quickly as you can without spilling it; immediately
wash off with cold water; have a receiver for the wash-
water, as it must be thrown away.
Wait until the surface of the plate is dry. If in a hurry,
blow it dry with bellows. When you adjust your plate for work, should any spots of moisture remain
on the surface, carefully take them up with blotting-paper.
Now, with the same varnish, stop out all the second lights. To prevent injury to your border, place
two blocks or old books under the ends of your rest.
When the second stopping out is set, put the plate through the same process with the same acid.
Again dry the plate, and stop out the third light parts; when set, apply the acid, but let it remain on
rather longer; wash, &c., as before directed.
You will now have all the flat tints, and only require the very dark ones. With your magnifying-
glass ascertain if the spots of resin remain on the plate; if so, it will bear biting again.
Should the ground remain sound enough to stand another application of the nitre, you must prepare
a mixture called touching stuff
Touching stuff.-Burn a good-sized cork to ashes, and take a piece of whiting about the size of a
filbert; mix them together with treacle; then add as much ivory-black as will make the mixture a dark
color, by the addition of a small quantity of sheep's or ox gall; it works almost as free as the varnish.
Make the composition to a lump. A small quantity to be used with water when required.
Again lay the plate for work. Paint over all the parts that are required to be very dark, such as
projecting foliage, and all sharp shadows, with the touching stuff. I say paint, for you must load all the
touches with as much of the mixture as can be placed on them.
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ETCHING.
When the touching stuff is dry, mix some thin turpentine varnish, slightly colored with lamp-black, and
with a larger brush go over the whole of the plate.
When this last varnish is set, pour on some very weak acid and water-the former washings of the
plate will do. With the soft camel-hair pencil used for the acid, work up the touching stuff until the
whole comes off; then wash the plate clean with cold water, and again apply the acid.
For this last biting the acid may remain on the plate as long as the ground will stand. This may
be ascertained by clearing your plate with the camel-hair pencil, and using the magnifying-glass.
The plate must now be cleaned. Release your border-wax as before described.
On this tint the oil-rubber should be very carefully used.
The plate being quite clean, place it under the shade. You will find your tints or bitings rather
sharper against each other than you wish.
The burnisher is to do away with this by rubbing with pressure the parts to be reduced in color. The
parts to be burnished should be slightly touched with the oil-rubber. Aqua-tint engraving requires
some skill in the use of the burnisher, which can only be acquired by practice.
The scraper will be found very useful for bringing out sharp lights and modulating the darker parts.
Should you have failed in making the first ground tell to your satisfaction, the plate must be
polished, and another ground laid. The second ground must be larger than the first, that is, contain
more resin.
The bordering, biting, and stopping out are as before. The plate should be sent for proof before the
second ground is laid.
When you have the proof you will be able to ascertain where you require increase and where
reduction of color. The burnisher must reduce, the increase can only be had by laying another ground.
Ground to etch on.-Mix a small quantity of turpentine varnish with turpentine very slightly colored
with black, but only sufficiently 80 to render the lines made by the needle perceptible. With this thin
varnish and a good-sized camel-hair brush, go over the plate longways; when that is set, repeat the
coating crossways; let it set, and lay it by for a night, if convenient.
The etching finished, border and bite as before directed, but with stronger acid.
Incidental instructions.-A few hints or cautions, apparently on trifles, may be found useful, and
enable the beginner to avoid many troublesome obstacles which, neglected, prevent engraving becoming
an entertaining amusement.
Great care must be taken, while laying the ground, that there is not much dust floating in the air;
for should the slightest particle of fluck lodge on the plate whilst wet, it will cause, what the engravers
call, an accident." Wherever the speck falls, the resin will corrode around it, and consequently form
a white spot on the ground where the acid has been applied. These accidents" are of little conse-
quence, unless they should happen on the sky. To do away with such light places, the chalk tool or
dotter must be used, which is simply a bent graver.
From pouring your ground mixture backwards and forwards, it is likely to become foul; it should
then be passed through a double piece of clean muslin, and put away in a bottle to settle.
The burnisher acts as principal in forming a good sky and background. As the action of the acid
will leave all the tints with a sharp edge, they must be softened down with the burnisher. Every
fresh aqua-tinta ground laid should be increased in the size of the grain, or the ground will become
murky.
To enrich and darken the foreground or foliage, etching over the parts with the etching-ground above
described, is much the easiest method.
Resin-ground engraving.-This style of engraving is well adapted to ornamental work, as great depth
of color can be obtained. The process is extremely simple.
The best white resin should be reduced to powder by pestle and mortar, then placed in a fine doubled
flannel, and tied up in a bag. The plate must be heated as in laying etching-ground, and the bag of
resin then powdered on the surface. The best plan is to lay the plate on a table, 80 that you may use
both hands. With the bag of resin pendent in the right hand, strike it against the left, (the bag must
be held some distance from the plate,) which will force the powdered resin to escape from the flannel
bag, and falling on the hot plate, will there fix itself in small spots, something similar to the aqua-tint
deposit, but much more enduring.
The stopping out process is exactly the same as in the aqua-tint.
By repeating the process with the flannel bag a positive black ground may be procured, as dark and
more enduring than a mezzotinto ground, which may be scraped on much in the same way.
Figs. 1608 to 1611, represent the apparatus, and the hand-craft to bring it into action ;-such as heating
the plate, laying the ground, smoking the ground, bordering the margin, biting-in the etching, taking off
the border, and polishing the plate.
Etching on glass.-The glass is covered with a thin ground of beeswax, and the design being drawn
with the etching-needle, it is subjected to the action of sulphuric acid sprinkled over with pounded flour
or Derbyshire spar. After four or five hours this is removed, and the glass cleaned off with oil of
turpentine, leaving the parts covered with the beeswax untouched. This operation may be inverted by
drawing the design on the glass with a solution of beeswax and turpentine, and subjecting the ground to
the action of the acid.
Stippling is also executed on the etching-ground by dots instead of lines made with the etching-
needle, which, according to the intensity of the shadow to be represented, are made thicker and closer.
The work is then bit in.
Etching on steel is executed much in the same way as in the process on copper. The plate is bedded
on common glazier's putty, and a ground of Brunswick black is laid in the usual way, through which
the needle scratches. It is then bit in, in the way above described.
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FAN.
621
FAN. A wheel with vanes revolving in a case or box, used for the production of a current of air or
gas. The principle of its operation depends on the law of centrifugal forces; the air is drawn in at the
centre and discharged at the periphery of the wheel it may therefore be applied either to draw air
from any place, or to force it into any place, as may be best suited to the purpose intended. The fan
is employed for draft or suction-in cotton pickers, for the extraction of dirt and for the formation of a
lap. It is used generally for blast to furnaces (see Blowing Machines) and for agricultural purposes, as
in the winnowing of grain; for ventilation it is used indiscriminately for draft or blast. When used to
promote the rapid combustion of fuel, it is evident, that whether the fan be placed in the smoke flue,
and the air be drawn into the fire, or whether it be placed in front of the fire, and the air forced in, the
result will be in most cases nearly the same. It is applied in both ways, but there are some mechani-
cal difficulties that interfere with the economical use of it in the former method, and it is therefore
almost universally applied to fires as a blowing machine.
Of the practical working of the fan. The power required to drive it, the proper velocity to be given
to it, and the density of air required, we know no more satisfactory experiments than those made by
W. Buckle, Esq., and published in the Practical Mechanic's and Civil Engineer and Architect Journals,
from which we extract his observations and the results of his experiments.
The experiments were made with a fan 8 feet 1013 inches diameter, the width of the vanes being
10} and the lengths 14 inches; the eccentricity of the fan 110 inches, with reference to the fan case,
the number of vanes being 5, and placed at an angle of 6° to the plane of the diameter; the inlet open-
ings on the sides of the fan chest 171 inches diameter, the outlet opening 12 inches square; the space
between the tips of the blades and the chest increasing from 1 inch on the exit pipe to 31 at the bot-
tom, in a line perpendicular with the centre. To the blast pipe leading to the tuyeres a slide valve
was attached, by means of which the area of the discharge was accurately adjusted to suit the required
density."
Velocity of the
Height of mer-
Height of col-
Area of dis-
Theoretical ve-
No. of
tips of vanes in
Density of air
cury in inches
umn of air
charge pipe
Indicated
locity of air in
Experi-
feet per sec-
in ounces per
equivalent to
equivalent to
in square
horse pow-
feet per sec-
ments.
ond.
square inch.
the density.
the density of
inches.
er.
ond.
air in feet.
1
2368
9.4
1.175
1093-10
closed.
960
264'4
2
2208
7.9
987
918.20
"
7.54
242-4
3
204'16
6-9
862
80191
"
6-68
2265
4
18528
5.6
r
651'21
"
586
204'1
5
171.5
45
562
5228
"
3.82
1829
6
144.10
3.5
437
406.5
"
2.214
161-2
7
2218
7
875
814-01
87.5
13:31
228-24
8
21709
7
875
"
38-125
11-02
22824
9
2218
6
750
69772
48.75
1381
211.8
10
2133
6
750
"
53125
12.54
2113
11
192.2
6
750
"
24875
6.48
2113
12
2218
5
625
581-48
60
1426
1929
13
211.48
5
625
"
65.
18-05
1929
14
1939
5
625
"
525
8-75
1929
15
174.5
5
625
"
225
453
1929
16
2218
4
5
465.1
69.
14.19
172.5
17
211-48
4
5
"
75.
13:33
172.5
18
196.68
4
5
"
65.62
9-58
172.5
19
177.62
4
5
"
78125
1132
1725
20
155.11
4
5
"
83125
33
1725
21
200-7
8
.875
34886
82.68
10-15
150-
22
174.5
3
375
"
10272
10-61
150-
23
1578
3
375
"
8963
7.56
150-
24
134.5
3
875
"
56.25
298
150-
25
160.5
2
250
232.5
151.6
91
122-
26
138.15
2
-250
"
124-125
589
122.
27
155.1
1
125
116.28
2649
938
86.26
28
138.15
1
125
"
264-9
7.27
86.26
By this table it will be seen that there are certain velocities with which the tips of the fans should
move according to the required density of air, and that there are certain laws which govern these ve-
locities.
The centrifugal force or density of the air coincides with the results obtained by the law of falling
bodies; that is, when the velocity is the same as the velocity which a body will acquire in falling the
height of a homogeneous column of air equivalent to a given density.
Having given the velocity of the air, and the diameter of the fan, to ascertain the centrifugal force-
Rule-Divide the velocity by 401, and again divide the square of the quotient by the diameter of
the fan. This last quotient multiplied by the weight of a cubic foot of air, at 60° Fahrenheit, is equal
to the force in ounces per square foot, which, divided by 144, is equal to the density of air per square
inch.
Or, substituting the following formula, we have D = N X 000034. Where D is the density of the
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622
FAN.
air in ounces per square inch, and N the number of revolutions of fan per minute, and V the velocity of
the tips of the fan in feet per second.
Having given the density in inches of mercury, (1 inch of which is equal to 8 OZ. pressure.) To find
the velocity which a body would acquire in falling the height of a column of air equivalent to that density
Rule.-Multiply the density in inches of mercury by 9303, and this product by 64. The square root
of the last product will be the velocity in feet per second, or more simply-
Multiply the square root of the density in inches of mercury by 244, and the product will be the
velocity.
It will be seen by the table that the velocity of the tips of the fan is practically somewhat less than
this theoretical velocity, and from the experiments we fix the laws which govern the velocity of the
tips of the fan 9-10th of the velocity a body would acquire in falling the height of a homogeneous column
of air equivalent to the density.
Experiments were made as to the proper size of the inlet openings, and on the proper proportions to
be given to the vane. The inlet openings in the sides of the fan chest were contracted from 17t, the
original diameter, to 12 and 6 inches diameter, when the following results were obtained:
First, that the power expended with the opening contracted to 12 inches diameter, was as 21 to 1
compared with the opening of 171 inches diameter; the velocity of the fan being nearly the same, as
also the quantity and density of air delivered.
Second, that the power expended with the opening contracted to 6 inches diameter, was as 21 to 1
compared with the opening of 171 inches diameter; the velocity of the fan being nearly the same, and
also the area of the efflux pipe, but the density of the air decreased one-fourth.
These experiments show that the inlet openings must be made of sufficient size, that the air may have
a free and uninterrupted action in its passage to the blades of the fan, for if we impede this action we
do 80 at the expense of power.
With a vane 14 inches long, the tips of which revolve at the rate of 2368 feet per second, air is con-
densed to 9.4 ounces per square inch above the pressure of the atmosphere, with a power of 96 horses;
but a vane 8 inches long, the diameter at the tips being the same, and having, therefore, the same velo-
city, condenses air to 6 ounces per square inch only, and takes 12-horse power.
Thus, the density of the latter is little better than 6-10th of the former, while the power absorbed is
nearly 1.25 to 1. Although the velocity of the tips of the vanes is the same in each case, the velocities
of the heels of the respective blades are very different; for, whilst the tips of the blades in each case
move at the rate of 236.8 feet per second, the heels of the 14-inch blades move at the rate of 90.8 feet
per second; and the heels of the 8-inch move at the rate of 15175 feet per second or, the velocity of
the heel of the 14 inch moves in the ratio of 1 to 1.67, compared with the heel of the 8-inch blade.
The longer blade approaching nearer the centre, strikes the air with less velocity, and allows it to enter
on the blade with greater freedom, and with considerable less force than the shorter one. The infer-
ence is, that the short blade must take more power at the same time that it accumulates a less quan-
tity of air.
These experiments lead me to conclude, that the length of the vane demands as great a consideration
as the proper diameter of the inlet opening. If there were no other object in view, it would be useless
to make the vanes of the fan of a greater width than the inlet opening can freely supply. On the pro-
portion of the length and width of the vane, and the diameter of the inlet opening, rest the three most
important points, viz., quantity, and density of air, and expenditure of power.
In the 14-inch blade, the tip has a velocity 2.6 times greater than the heel; or, by the laws of cen-
trifugal force, the air will have a density 26 times greater at the tip of the blade than that at the heel.
The air cannot enter on the heel with a density higher than that of the atmosphere, but in its passage
along the vanes, it becomes compressed in proportion to its centrifugal force. The greater the length
of vane, the greater will be the difference of the centrifugal force between the heel and the tip of the
blade; consequently, the greater the density of the air.
Reasoning, then, from these experiments, I recommend, for easy reference, the following proportions
for the construction of the fan :-
Let the width of the vanes be one-fourth of the diameter.
Let the diameter of the inlet openings in the sides of the fan chest be one-half the diameter of the fan.
And, let the length of the vanes be one-fourth of the diameter of the fan.
In adopting this mode of construction, the area of the inlet openings in the sides of the fan chest will
be the same as the circumference of the heel of the blade, multiplied by its width; or the same area as
the space described by the heel of the blade.
The following table gives the sizes of fans varying from 3 to 6 feet diameter:
TABLE OF BEST PROPORTIONS OF FANS.
Diameter of Fan.
Width of Vane.
Length of Vane.
Diameter of inlet opening.
P.
in.
IL
in.
ft.
in.
ft.
in.
8
0
0
9
0
9
1
6
8
6
0
10}
0
101
1
9
4
0
1
0
1
0
2
0
4
6
1
If
1
11
2
3
5
0
1
8
1
8
2
6
6
0
1
6
1
6
3
0
I recommend the proportions in the above table for density ranging from 8 to 6 ounces per square
inch, and for higher densities, vis. from 6 to 9, or more ounces, the sizes given in the following table:
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FALLING STOCKS.
623
Diameter of Fan.
Width of Vane.
Length of Vane.
Dismeter of inlet opening.
ft.
in.
ft.
in.
P.
in.
ft.
in.
8
0
0
7
1
0
1
0
8
6
0
81
1
If
1
3
4
0
0
91
1
81
1
6
4
6
0
101
1
41
1
9
5
0
1
0
1
B
2
0
6
0
1
2
1
10
2
4
The dimensions of the above tables are not laid down as prescribed limits, but as approximations
obtained from the best results in practice.
Experiments were also made with reference to the admission of air into the transit or outlet pipe. By
a slide the width of the opening into this pipe was varied from 12 to 4 inches. The object of this was to
proportion the opening to the quantity of air required, and thereby to lessen the power necessary to
drive the fan. It was found that the less this opening is made, provided we produce sufficient blast,
the less noise will proceed from the fan; and by making the tops of this opening level with the tips of
the vane, the column of air has little or no reaction on the vanes.
As to the pressure of the blast commonly required in smithies, the range is from 4 to 5 ounces per
square inch. And an ordinary eccentrically placed fan, 4 feet diameter-the blades 10 inches wide and
14 inches long, and making 870 revolutions per minute-will supply air at a density of 4 ounces per
square inch to 40 tuyeres, each being 18 inch diameter, without any falling off in density.
The above embody the results and deductions from Mr. Buckle's experiments on the common form of
eccentrically placed fan; but, besides this form, there is a great variety of others, on which, it is true,
no scientific experiments have been made of their working, but which, in practice, have given very sat-
isfactory results. We give drawings and slight descriptions of two in common use.
Figs. 1612, 1613, and 1614, represent the fan of F. P. Dimpfel, of Philadelphia
1614.
1613.
1612.
Fig. 1612 is a side view. Fig. 1613 an end view, looking into the outlet pipe. Fig. 1614 a section.
It will be seen that the vanes of the fan are in the form of a trapezium, and that the air-chamber not
only extends all round the periphery of the fan, but also at the sides.
This fan is in use at the Novelty Works, New York; where it is also made, and is highly recom-
mended by the proprietors of various foundries and forges where it is in operation.
1615.
1616.
Figs. 1615 and 1616 represent sections of a fan made by Wm. Mason. Taunton, Mass. The vanes are
three in number, of a triangular form: the air-chamber is circular, and extends entirely round the fan
the arms of the fan are curved, and in movement present the convex side to the impelled air. The
construction of this fan is extremely simple: the fan is cast entire in one piece; the case enclosing the
fan and forming the air-chamber, is cast in halves and bolted together. This fan is extensively used,
and gives general satisfaction. Both Dimpfel and Mason's fans are made of various sizes to suit the
purposes for which they are designed.
FALLING STOCKS. Each mill consists of a pair of heavy oak hammers, weighing about 75
pounds each, and lifted alternately by the cams a a', on opposite sides of the tappet-wheel A, as in the
drawing. The hammers should be about 91 inches wide each, and 16 to 17 inches deep. The cloth to
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624
FELLOE MACHINE.
be milled is placed in the cup of the mill B, with a small quantity of soap. The hammers are then put
in operation and run from 12 to 48 hours, according to the weight of the fabric, Fig. 1617. See FULLING.
1617.
65
A
B
a
a
FEED APPARATUS. See DETAILS OF ENGINES, page 513.
FELLOE MACHINE This is a machine for cutting felloes of wheels out of plank, on which valua-
ble improvements have been made by Joshua and Levi Adams, and T.H. Mores, of Ainherst, Mass.
K
1618.
A
C
+
:
D
E
9
h
A
G
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FILES.
625
Fig. 1618 is an elevated section of the machine at the line X X of Fig. 1619, which is a horizontal view
with the friction wheels removed. The same letters refer to like parts OD both the figures.
A is a frame, B is an upright shaft resting in a movable step at its lower end, and having a cireular
plate a, secured to its upper end, above the hub b. C is a horizontal beam secured between projections
on the upper surface of the circular plate. D are angular metallic boxes with flanges on their sides
attached to the beam by the straps d. E are the cutters of the desired form passing through openings
in the boxes and adjusted by screws. F is an upright shaft resting in a step in the frame and turning
in a box screwed to a vibrating timber at its upper end, and with a friction wheel and pulley f at the
top, and a gang of pulleys g below, around which is seen the band h extending around a pulley i on B.
G is a lever arranged below the frame and secured at one end to the front of the same by a pin upon
which it moves, and at its opposite end upon a similar lever j, which is connected to a cross-head,
moving between upright wave. H is a vertical screw shaft passing through a screw in the cross-head,
and having a button or shoulder at its lower end, which shoulder turns in a permanent block in the
frame. Q is a lever moving on a fulcrum, and connected at the end by a rod, which is connected to a
lever below the frame, having a weight hung on its upper end to counterbalance the weight of the ver-
tical shaft of cutters and levers to relieve the screws of part of the pressure and prevent it from wear-
ing. K, Fig. 1619, is a horizontal beam containing the boxes in which the upper end of the upright
boxes turn, and it is provided with tennons at the ends which fit into mortises in the vertical parts of
the frame and has cords attached to its ends, one of which, with a weight, pa-ses over a pulloy in the
outside, and the other cord passes over another pulley and is attached to a lever Z W, moving on a ful-
crum, for lowering the cross-head by lowering the said lever.
0.00
E
Z
D
1619.
P
K
H
When it is desired to cut a felloe, the plank from which it is to be cut is placed upon the tables and
firmly secured by the dogs and clamps 1. The upright shaft is then set in motion by the friction wheels
being brought in contact by the lever, and therefore the cutter shaft by the band h is set in motion.
The cutters EE. are set in the cutter heads by the straps dd, 80 that one cutter shall move in a circle
cutting the outside of the felloe and the other cuts the inside circle, while the cutter shaft can be raised
or lowered by the lever G, to cut the required depth. The dogs and clamps can be shifted on the table
for larger or smaller feiloes, and the cutters can be shifted on CCC. to correspond with the same.
FELTING. The process of blending or matting different kinds of fur or wool into a compact texture.
A heavy kind of fell is used as a lining to the magazines of men-of-war, between two thicknesses of
wood also to cover over the steam boilers of steam-ships. An Indian-rubber felt, composed of
caoutchouc and cork, is now made, but is as yet not much in use. See HAT MANUFACTURE
FILES. The file is a strip or bar of steel, the surface of which is cut into fine points or teeth, that
act by a species of cutting, closely allied to abrasion.
Files are almost endle-s in variety; and there is some four, five, or six features in every file, to
adapt the instrument to the several kinds of work for which the file is used. Most of the names of
files express these different features; for instance the three following files are in common use :-
6 inch,
blunt,
single-cut,
saw file.
9 inch,
taper.
smooth,
half round file.
12 inch,
parallel.
rough,
cotter file.
The watchmaker frequently uses files not exceeding three-quarters of an inch in length; mathemati-
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FILES.
cal instrument makers and gunmakers employ files from about 4 to 14 inches long; and machinists
and engineers commonly require files from about 8 to 20 inches long, and sometimes use those of two
and three feet and upwards in length.
Almost all files are required to be as straight as possible in their central line, and are distinguished
as taper, blunt, and parallel files; a very insignificant number of files are made curvilinear in their
central line, as in the rifflers used by sculptors and carvers, and some other files.
Many files that are in all other respects alike, differ in the forms and sizes of their teeth. Three
forms of teeth are made, those of double-cut files, those of Roats, or single-cut files, and those of rasps.
The floats and rasps are scarcely used but for the woods and soft materials; the double-cut files are
used for the metals and general purposes.
In a double-cut file, the thousands of points or teeth occur from two series of straight chisel-cuts
crossing each other in a single-cut file or float, the ridges occur from the one series of chisel-cuts, which
are generally square across the float; and in a rasp the detached teeth are made by solitary indenta-
tions of a pointed chisel or punch.
Double-cut files are made of several gradations of coarseness, and which are thus respectively
named :-
1. Rough.
1. Rough.
2. Middle-cut.
2. Bastard.
3. Bastard.
8. Second-cut.
4. Second-cut.
4. Smooth.
5. Smooth.
5. Dead-smooth.
6. Superfine.
Some files have one or more edges that are left uncut, and these are known as safe-edges, because
such edges are not liable to act upon those parts of the work against which they are allowed to rub,
for the purpose of guiding the instrument. Occasionally the edges alone of files are cut, and the sides
are left safe or smooth, as in some warding files, which nearly resemble saws.
The names of files are often derived from their purposes, as in saw-files, slitting, warding, and cotter
files; the names of others from their sections, as square, round, and half-round files.
Fig. 1620. Sections derived from the Square.
A
B
C
D
E
F
G
II
Flg. 1621. Sections derived from the Circle.
I
K
L
M
N
o
P
Q
Fig. 1622. Sections derived from the Triangle.
R
S
T
V
W
X
Y
Z
Files of all the sections represented in the groups, Figs. 1620 to 1622, are more or less employed,
although many of them are almost restricted to particular purposes.
Taper files, or taper flat files, are made of various lengths from about 4 to 24 inches, and are rectan-
gular in section as in B, Fig. 1620; they are considerably rounded on their edges, and a little also in
their thickness; their greatest section being towards the middle of their length or a little nearer to
the handle, whence these files are technically known to be " bellied;" they are cut both on their faces
and edges with teeth of four varieties; namely, rough, bastard, second-cut, and smooth-cut teeth.
Taper flat files are in extremely general use amongst smiths and mechanics, for a great variety of or-
dinary works.
Hand files or flat files resemble the above in length, section, and teeth, but the hand files are nearly
parallel in width, and somewhat less taper in thickness than the foregoing. Engineers, machinists,
mathematical instrument makers, and others, give the preference to the hand file for flat surfaces and
most other works.
Cotter files are always narrower than hand files of the same length and thickness; they are nearly
flat on the sides and edges, 80 as to present almost the same section at every part of their length, in
which respect they vary from 6 to 22 inches. Cotter files are mostly used in filing grooves for the
cotters, keys, or wedges used in fixing wheels on their shafts, whence their name.
Pillar files also somewhat resemble the hand files, but they are much narrower, somewhat thinner,
as in C, and are used for more slender purposes, or for completing works that have been commenced
with the hand files. Pillar files have commonly one safe edge, and vary from 3 to 10 inches in length.
Half-round files are nearly of the section L, notwithstanding that the name implies the semicircular
section; in general the curvature only equals the fourth to the twelfth part of the circle.
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Triangular files are of the section R, and from 2 to 16 inches long; they are used for internal angles
more acute than the rectangle, and also for clearing out square corners.
Cross files, or crossing files, are of the section M, or circular on both faces, but of two different
curvatures.
Round files, of the section I, range from the length of 2 to 18 inches; they are in general taper,
and much used for enlarging round holes.
Square files measure in general from 2 to 18 inches in length, and are mostly taper.
Equalling files are files of the section D. In width they are more frequently parallel than taper;
in thickness they are always parallel. They are in general cut on all faces, and range from 2 to 10
inches long.
Knife files are of the section T, and in general very acute on the edge, they are made from 2 to 7
inches long, and are as frequently parallel as taper.
Slitting files, called also feather-edged files, resemble the last in construction and purpose, except in
having, as in section V, two thin edges instead of one; they are almost always parallel.
Rubbers are strong heavy files, generally made of an inferior kind of steel; they measure from 12
to 18 inches long, from 1 to 2 inches on every side, and are made very convex: they are frequently
designated by their weight alone, which varies from about 4 to 15 lbs. Rubbers are nearly restricted
to the square and triangular sections A and R. Some few rubbers are made nearly square in section,
but with one side rounded, as if the sections K and B were united: these are called half-thick.
Many artisans, and more particularly. the watchmakers, require other files than those described, and
it is therefore proposed to add the names of some of the files to which the sections refer, premising that
such names as are printed in Italics designate small files especially used in watchmaking.
Names of some of the Files corresponding with the Sections A to Z, (represented by Figs. 1620 to 1622.)
A.-Square files, both parallel and taper, some with one safe side; also square rubbers.
B.-When large, cotter files; when small, verge and pivot files.
C.-Hand files, parallel and flat files; when small, pottance files; when narrow, pillar files; to these
nearly parallel files are to be added the taper flat files.
D.-When parallel, equalling clock-pinion and endiess-screw files; when taper, slitting, entering, ward-
ing, and barrel-hole files.
E-French pivot and shouldering files, which are small, stout, and have safe-edges; when made of
large size, and right and left, they are sometimes called parallel V files, from their suitability to
the hollow V V's of machinery.
F.-Name and purpose similar to the last.
G.-Flat file with hollow edges, principally used as a nail file for the dressing-case.
H.-Pointing mill-saw file, round-edge equalling file, and round-edge joint file; all are made both
parallel and taper.
I-Round file, gulleting saw file, made both parallel and taper.
K-Frame saw file for gullet teeth.
L-Half-round file. Nicking and piercing files, also cabinet floats and rasps; all these are usually
taper. Files of this section which are small, parallel, and have the convex side uncut, and have
also a pivot at the end opposite the tang, are called round-off files.
M.-Cross, or crossing files, also called double half-rounds.
N.-Oval files; oval gulleting files for large saws, called by the French limes à double dos. Oval-dial
file when small.
O.-Balance-wheel or swing-wheel files, the convex side cut, the angular sides safe.
P.-Swaged files, for finishing brass mouldings; sometimes the hollow and fillets are all cut.
Q-The curvilinear file.
R.-Triangular, three-square, and saw files, also triangular rubbers, which are out on all sides.
S.-Cant file, probably named from its suitability to filing the insides of spanners, for hexagonal and
octagonal nuts, or as these are generally called, six or eight canted bolts and nuts; the cant files
are cut on all sides.
T.-When parallel, Aat-dovetail, banking, and watch-pinion files; when taper, knife-edge files. With
the wide edge round and safe, files of the section T are known as moulding files and clock-
pinion files.
V.-Screw-head files, feather-edged files, clock and watch-slitting files.
W.-Is sometimes used by engineers in finishing small grooves and key ways, and is called a valve file,
from one of its applications.
X.-A file compounded of the triangular and half-round file, and stronger than the latter; similar files
with three rounded faces have also been made for engineers.
Y.-Double or checkering files, used by cutlers, gunmakers, and others. The files are made separately
and riveted together, with the edge of the one before that of the other, in order to give the
equality of distance and parallelism of checkered works, just as in the double saws for cutting
the teeth of racks and combs.
Z-Double file, made of two flat files fixed together in a wood or metal stock; this was invented for
filing lead pencils to a fine conical point.
The manufacture of files.-The pieces of steel, or the blanks intended for files, are forged out of bars
of steel that have been either tilted or rolled as nearly as possible to the sections required, 80 as to
leave but little to be done at the forge; the blanks are afterwards annealed with great caution, so
that in neither of the processes the temperature known as the blood-red heat may be exceeded. The
surfaces of the blanks are now rendered accurate in form and quite clean in surface either by filing
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FILES.
or grinding. For the smaller files the blanks are mostly filed into shape as the more exact method for
the larger, the blanks are more commonly ground on large grindstones as the more expeditious method;
in some few cases the blanks are planed in the planing machine, for those called dead-parallel files.
The blank before being cut is slightly greased, that the chisel may slip freely over it.
The file-cutter is seated before a square stake or anvil, and places the blank straight before him,
with the tang towards his person; the ends of the blank are fixed down by two leather straps or loops,
one of which is held fast by each foot.
The largest and smallest chisels commonly used in cutting files are represented in two views; and
half size in Figs. 1623 and 1624. The first is a chisel for large rough files; the length is about 3 inches,
the width 21 inches, and the angle of the edge about 50 degrees; the edge is perfectly straight, but
the one bevel is a little more inclined than the other. and the keenness of the edge is rounded off, the
object being to indent, rather than cut the steel this chisel requires a hammer of about 7 or 8 lbs.
weight. Fig. 1624 is the chisel used for small superfine files its length is 2 inches. the width 1 inch;
1623.
1624.
1395.
"
a
b
1626.
it is very thin, and sharpened at about the angle of 35 degrees; the edge is also rounded, but in a
smaller degree it is used with a hammer weighing only one to two ounces, as it will be seen the
weight of the blow mainly determines the distance between the teeth. Other chisels are made of
intermediate proportions, but the width of the edge always exceeds that of the file to be cut.
The first cut is made at the point of the file; the chisel is held in the left hand, at a horizontal angle
of about 55 degrees, with the central line of the file, as at aa, Fig. 1625, and with a vertical inclina-
tion of about 12 to 4 degrees from the perpendicular, as represented in the figures 1623 and 1624,
supposing the tang of the file to be on the left-hand side. The following are nearly the usual angles for
the vertical inclination of the chisels; namely, for rough rasps, 15 degrees beyond the perpendicular;
rough files, 12 degrees; bastard files, 10 degree second-cut files, 7 degrees; smooth-cut files, 5 de-
grees: and dead-smooth-cut files, 4 degrees. The blow of the hammer upon the chisel causes the latter
to indent and slightly to drive forward the steel, thereby throwing up a trifling ridge or burr; the chisel
is immediately replaced on the blank, and slid from the operator until it encounters the ridge previously
thrown up, which arrests the chisel or prevents it from slipping further back, and thereby determines
the succeeding position of the chisel. The chisel having been placed in its second position is again
struck with the hammer, which is made to give the blows as nearly as possible of uniform strength;
and the process is repeated with considerable rapidity and regularity, 60 to 80 cuts being made in one
minute, until the entire length of the file has been cut with inclined, parallel, and equidistant ridges,
which are collectively denominated the first course. So far as this one face is concerned, the file, if
intended to be single-cut, would be then ready for hardening; and when greatly enlarged, its section
would be somewh.it as in Fig. 1626. The teeth of some single cut files are much less inclined than 55
degrees; those of floats are in general square across the instrument.
Most files, however, are double cut, or have two series or courses of chisel cuta, and for these the
surface of the file is now smoothed by passing a smooth file once or twice along the face of the teeth. to
remove only 80 much of the roughness as would obstruct the chisel from aliding along the face in
receiving its successive positions, and the file is again greased.
The second course of teeth is now cut, the chisel being inclined vertically as before, or at about 12
degrees, but horizontally, about 5 to 10 degrees from the rectangle, as at bb, Fig. 1625; the blows are
now given a little less strongly. 80 as barely to penetrate to the bottom of the first cuts, and consequently
the second course of cuts is somewhat finer than the first. The two series of courses fill the surface of
the file with teeth which are inclined towards the point of the file. and that when highly magnified
much resemble in character the points of cutting tools generally, as seen in Fig. 1626.
If the file is flat and to be cut on two faces, it is now turned over; but to protect the teeth from the
hard face of the anvil, a thin plate of pewter is interposed. Triangular and other file< require blocks of
lead having grooves of the appropriate sections to support the blanks, 80 that the surface to be cut may
be placed horizontally. Taper files require the teeth to be somewhat finer towards the point, to avoid
the ri k of the blank being weakened or broken in the act of its being cut, which might occur if as
much force were used in cutting the teeth at the point of the file, as in those at its central and stronger
pa:t
Eight courses of cuts are required to complete a double cut rectangular file that is cut on all faces,
but eight, ten, or even more courses are required in cutting only the une rounded face of a half-round
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file. There are various objections to employing chisels with concave edges, and therefore in cutting
round and half-round files the ordinary straight chisel is used and applied as a tangent to the curve.
It will be found that in a smooth half-round file one inch in width, that about twenty courses are required
for the convex side, and two courses alone serve for the flat side. In some of the double-cut gullet-
tooth saw files, of the section K, as many as twenty-three courses are sometimes used for the convex
face, and but two for the flat. The same difficulty occurs in a round file, and the surfaces of curvilinear
files do not therefore present, under ordinary circumstances, the same uniformity as those of flat files.
Hollowed files are rarely used in the arts, and when required it usually becomes imperative to
employ a round-edged chisel, and to cut the file with a single course of teeth.
The teeth of rasps are cut with a punch, which is represented in two
views, Fig. 1627. The punch for a fine cabinet rasp is about 31 inches long,
1627.
and 1 square at its widest part. Viewed in front, the two sides of the point
meet at an angle of about 60 degrees viewed edgeways, or in profile, the
edge forms an angle of about 50 degrees, the one-face being only a little
inclined to the body of the tool.
In cutting rasps, the punch is sloped rather more from the operator than
the chisel in cutting files, but the distance between the teeth of the rasp
cannot be determined as in the file, by placing the punch in contact with the
burr of the tooth previously made. By dint of habit, the workman moves
or, technically, hops the punch the required distance; to facilitate this
movement, he places a piece of woollen cloth under his left hand, which pre-
vents his hand coming immediately in contact with, and adhering to the
anvil.
The teeth of rasps are cut in rather an arbitrary manner, and to suit the
whims rather than the necessities of the workmen who use them. Thus the
lines of teeth in cabinet rasps, wood rasps, and farriers' rasps, are cut in
lines sloping from the left down to the right hand side; the teeth of rasps
for boot and shoe last makers and some others, are sloped the reverse way;
and rasps for gun-stockers and saddle-tree makers are cut in circular lines
or crescent form. These directions are quite immaterial; but it is important that every succeeding tooth
should cross its predecessor, or be intermediate to the two before it; as if the teeth followed one another
in right lines, they would produce furrows in the work, and not comparatively smooth surfaces.
In cutting files and rasps they almost always become more or less bent, and there would be danger
of breaking them if they were set straight whilst cold; they are consequently straightened whilst they
are at the red heat, immediately prior to their being hardened and tempered.
Previously to their being hardened, the files are drawn through beer grounds, yeast, or other sticky
matter, and then through common salt, mixed with cow's hoof previously roasted and pounded, and
which serve as a defence to protect the delicate teeth of the file from the direct action of the fire. The
compound likewise serves as an index of the temperature, as on the fusion of the salt, the hardening
heat is attained the defence also lessens the disposition of the files to crack: or clink on being immersed
in the water.
The file, after having been smeared over as above, is gradually heated to a dull red, and is then
mostly straightened with a leaden hammer on two small blocks also of lead; the temperature of the
file is afterwards increased until the salt on its surface just fuses, when the file is immediately dipped
in water. The file is immersed, quickly or slowly, vertically or obliquely, according to its form; that
mode being adopted for each variety of file which is considered best calculated to keep it straight.
It is well-known that from the unsymmetrical section of the half-round file, it is disposed, on being
immersed, to become hollow or bowed on the convex side, and this tendency is compensated for by
curving the file whilst soft in a nearly equal degree in the reverse direction.
It nevertheless commonly happens, that with every precaution the file becomes more or less bent
in hardening. and if so, it is straightened by pressure, either before it is quite cold, or else after it
has been partially reheated. The pressure is variously applied, sometimes by passing one end of the
file under a hook, supporting the centre on a prop of lead, and bearing down the opposite end of the
file; at other times by using a support at each end, and applying pressure in the middle, by means of a
lever, the end of which is hooked to the bench. Large files are always straightened before they are
quite cooled after the hardening, and whilst the central part retains a considerable degree of heat.
When straightened, the file is cooled in oil, which saves the teeth from becoming rusty.
The tangs are now softened to prevent their fracture; this is done either by grasping the tang in a
pair of heated tongs, or by means of a bath of lead contained in an iron vessel with a perforated cover,
through the holes in which the tangs are immereed in the melted lead that is heated to the proper
degree. The tang is afterwards cooled in oil, and when the file has been wiped and the teeth brushed
clean, it is considered fit for use.
The superiority of the file will be found to depend on four points,-the primary excellence of the
steel-the proper forging and annealing without excess of heat-the correct formation of the teeth-and
the success of the hardening.
Means of grasping the file.-In general. the end of the file is forged simply into a taper tang or spike,
for the purpose of fixing it in its wooden handle, but wide files require that the tang should be reduced
in width, either as in Fig. 1628 or 1629. The former mode, especially in large files, is apt to cripple
the steel and dispose the tang to break off, after which the file is nearly useless. The curvilinear tang,
Fig. 1629, is far less open to this objection. Some workmen make the tangs of large files red-hot, that
they may burn their own recesses in the handles, but this is objectionable, as the charred wood is apt
to crumble away and release the file. It is more proper to form the cavity in the handle with coarse
floats made for the purpose.
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In driving large files into their handles it is usual to place the point of the file in the hollow behind
the chaps of the tail vice, and to drive on the handle with a mallet or hammer. Smaller files are fixed
obliquely in the jaws of the vice, between clamps of sheet brass, to prevent the teeth either of the vice
or file from being injured, and the handle is then driven on.
In the double-ended rifflers, or bent files, Fig. 1630, and in some other files, there is a plain part in
the middle, fulfilling the office of a handle; and in several of the files and rasps made for dentists,
farriers, and shoemakers, the tool is also double, but without any intermediate plain part, so that the
one end serves as the handle for the other.
1631.
1628.
1632.
1629.
1633
1630.
1634.
In general, the length of the file exceeds that of the object filed, but in filing-large surfaces it becomes
ecasionally necessary to attach cranked handles to the large files or rubbers, as in Fig. 1631, in order
to raise the hand above the plane of the work. Sometimes the end of the file is simply inclined, as in
Fig. 1632, or bent at right angles, as in Fig. 1633, for the attachment of the wooden handles represented;
but the last two modes prevent the second side of the file from being used, until the tang is bent the
reverse way. The necessity for bending the file is avoided by employing as a handle a piece of round
iron, I or } inch in diameter, bent into the semicircular form as an arch, the one extremity (or abutment)
of which is filed with a taper groove to fit the tang of the file, whilst the opposite end is flat, and rests
upon the teeth; in this manner both sides of the file may be used without any preparation.
Fig. 1684 represents, in profile, a broad and short rasp with fine teeth, used by iron-founders in
smoothing off loam moulds for iron castings; this is mostly used on large surfaces, to which the ordinary
handle would be inapplicable, and the same kind of tool when made with coarser teeth, will be recog-
mised as the baker's rasp.
Cabinet-makers sometimes fix the file to a block of wood to serve for the grasp, and use it as a plane.
Thns mounted. the file may also be very conveniently used on a shooting-board, in filing the edges of
plates to be inlaid.
1635.
0
b
a
0
c,
©
o
0
d
c
Fig. 1635 represents a very good arrangement of this kind. a a is the plan, and b the section of the
file stock, cc is the plan of the shooting-board, and d its section. Two files (that are represented black)
are screwed against the sides of a straight bar of wood, which has also a wooden sole or bottom plate,
that projects beyond the files, so that the smooth edge of the sole may touch the shooting-board instead
of the file teeth. The shooting-board is made in three pieces, so as to form a groove to receive the file
dust, which would otherwise get under the stock of the file. The shooting-board has also a wooden
stop 8, faced with steel, that is wedged and screwed into a groove made across the top piece, and the
stop being exactly at right angles, serves also to assist in squaring the edges of plates or the ends of
long bars, with accuracy and expedition.
Short pieces of files (or tools as nearly allied to sawa) are occasionally fixed in the ends of wooden
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stocks, in all other respects like the routing gages of carpenters, as seen in two views in Fig. 1636. The
coopers' croze is a tool of this description.
Files intended for finishing the grooves in the edges of slides, are sometimes made of short pieces of
steel of the proper section, (see Fig. 1637,) cut on the surfaces with file teeth, and attached in various
ways to slender rods or wires, serving as the handles, and extending beyond the ends of the slides: or
the handle is at right angles to the file, and formed at the end, as a staple, to clip the ends of the short
file, as in reaching the bottom of a cavity. Files intended to reach to the bottom of shallow cavities are
also constructed as in Figs. 1638 and 1639, or sometimes an inch or more of the end of an ordinary file
is bent some 20 or 80 degrees, that the remainder may clear the margin of the recess.
1638.
1639.
1636.
1640.
1641
W
1642.
1637.
To stiffen slender files, they are occasionally made with tin or brass backs, as in Figs. 1640 and
1641 such are called dovetail files; and thin equalling files are sometimes grasped in a brass frame,
Fig. 1642, exactly like that used for a metal frame-saw.
Notwithstanding the great diversity in the files already alluded to, it is to be remarked that all those
hitherto noticed are made entirely of steel, and their teeth are all produced in the ordinary manner by
means of the chisel and hand hammer. It now remains to notice a few of the less usual kinds of rasps,
floats, and files, the teeth of which are, for the most part, produced by means differing from those
already described.
The rifflers, Fig. 1630, used by sculptors, are required to be of numerous curvatures, to adapt them
to the varying contour of works in marble. In general the rifflers are made of steel in the ordinary
mode, but they have also been made of wrought-iron, and slightly case-hardened, in which case the
points of the teeth become converted into steel, but the general bulk of the instrument remains in its
original state as soft iron consequently such case-hardened rifflers admit of being bent upon a block
of lead with a leaden mallet, so that the artist-is enabled to modify their curvatures as circumstances
may require.
Several kinds of floats are made with coarse, shallow, and sharp teeth; these teeth could not be cut
with the chisel and hammer in the ordinary manner, but are made with a triangular file. Figs. a to 1,
1648, represent the sections of several of these floats, which have teeth at the parts indicated by the
double lines; for instance, a is the float, b the graille, c the found, d the carlet, e the topper, used by the
born and tortoiseshell comb-makers. The floats f to i are used by ivory carvers for the handles of
knives, and in the preparation of works, the carving of which is to be completed by scorpers and
gravers; k and l are used in inlaying tools in their handles; k is made of various widths, and is
generally thin, long, and taper; 1 is more like a key-hole saw.
1643.
1644.
a
b
c
e
6
1645.
0
0
Q
©
1646.
f
i
l
The larger of the floats, such as those a to e, used by the comb-makers, are kept in order principally
by the aid of a burnisher, represented in two views in Fig. 1644; the blade is about 2 inches long, 1 inch
wide, and 1-16th thick; the end is mostly used, and which is forcibly rubbed, first on the front edge of
every tooth, as at a, Fig. 1645, and then on the back, as at b, by which means a slight burr is thrown
up on every tooth, somewhat like that on the joiner's scraper; but in this art the burnisher is commonly
named a turn file.
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FILE AND RASP MACHINE.
The quannet is a float resembling Fig. 1634, but having coarse filed teeth, of the kind just described;
it may be considered as the ordinary flat file of the horn and tortoiseshell comb-makers, and in using
the quannet, the work is mostly laid upon the knee as a support. An ingenious artisan in this branch,
Mr. Michael Kelly, invented the quannet represented in Figs. 1645 and 1646. The stock consists of a
piece of beach-wood, in which, at intervals of about one-quarter of an inch, cuts inclined nearly 30
degrees with the face, are made with a thin saw; every cut is filed with a piece of saw-plate. The
edges of the plates and wood are originally filed into the regular float-like form, and the burnisher is
subsequently resorted to as usual. The main advantage results from the small quantity of steel it is
necessary to operate upon, when the instrument requires to be restored with the file. From this cir-
cumstance, and also from its less weight, the wooden quannet, Fig. 1645, is made of nearly twice the
width of the steel instrument, Fig. 1634, and the face is slightly rounded, the teeth being sometimes
inserted square across, as in a float, at other times inclined some 30 degrees, as in R single-cut file.
The cutting of files by machinery.-The practical introduction of machinery for cutting files appears
to be due to a Frenchman of the name of Raoul, at about the close of the last century, but the descrip-
tion of the machine has not been published, and the manufacture is now carried on by his son. His
files are beautiful specimens of workmanship, being more strictly regular, and also less liable to clog or
pin when in use, than files cut by hand, as usual.
His manufacture is principally limited to watch files with flat sides, and measuring from I of an inch
to 5 or 6 inches long.
Machines have been recently constructed in England for cutting both large and small files, and half
a dozen or more at a time. The details of the machines display great ingenuity and skill, but there are
various drawbacks that prevent, under ordinary circumstances, any great commercial advantage in the
machine over the hand process, from which considerations the patent file-cutting machines are not at
present used.
We give drawings and a description of a recently invented file machine, patented in 1847 by George
Winslow, of Boston. We know not how far it has been successful, but it is well worthy of notice as an
example of ingenious combinations, and to illustrate what has been done in this department of
mechanism.
FILE AND RASP MACHINE Fig. 1647 represents a plan view of this apparatus or machinery,
as laid down by the patentee, in the drawing attached to the specification; and Fig. 1648 is a side ele-
vation of the same. It consists of a rectangular framework a a, which may be of wood or other suita-
ble material; stretched across this framework is a plate b, on which are two levers a' a', disposed on
either side of the machine and moving on fulcra a" a""; the long ends of these levers are connected to
a sort of toggle d', by means of the straps c', and the short ends are connected by links to the blocks or
chisel-holders dd; the chisel-holders move on the plate b, and are guided by the brackets eeee, and
though constrained to move in a particular direction, are free to turn round, 80 that the chisels ff may
be adjusted to any angle at which it may be required to form the indentations or teeth on the blank g.
This is supported between two poppets hh, the one receiving the shank or tang in a socket, in which it
is secured by binding screws, and the other is supported by a centre, received by an indentation made
in the end of the blank. It will be observed that a tooth on each side of the blank is produced at the
same time, the pressure of one chisel sustaining the opposing force of the other, the poppets h h being
80 fitted to their support j as to admit of a movement in a transverse direction, to allow for any inequality
in the surface of the blank i is a slide, which is fitted between dovetailed grooves, so as to admit of
sliding in a longitudinal direction. This slide forms the immediate support for the blank, and is strength-
ened by an arch-piece p', as seen at Fig. 1648. This slide is caused to travel by means of a screw i,
which passes through a nut attached to the bottom of the slide. A plate b' is fitted on two longitudi-
nal slides 'n'. This plate receives a reciprocating motion from the main driving-shaft, through the
intervention of the connecting-rod a", and upright lever p. The driving-shaft is furnished with a disk
or plate x, having a radial slot cut therein, in which the crank pin can be adjusted, 80 as to vary the
throw, and consequently the motion of the connecting-rod a". This rod is also adjustable in the verti-
cal lever p, so as to bring the connection nearer to, or further from, the fulcrum on which it moves.
Each movement of this sliding plate b' produces a closing of the cutters ff, by reason of the movement
of the toggles d' d', which are mounted on the plate b', and thus raise a tooth by forming an indenta-
tion in the blank.
Now in cutting files by this machine, it is necessary to begin the cut at the point or thinnest part of
the file, when the greatest range of movement is given to the plate b'; and as the cutting proceeds to-
wards the thick part of the blank, the movement of the plate b' must decrease, imparting less move-
ment to the levers a' a'; and consequently the cutters will not be brought 80 close together; but in re-
ducing this movement of the plate, the angle formed by the levers c' c' will be less, and consequently
their power will decrease also, but which is compensated for by an apparatus hereafter explained. As
the cutters always close at the same point, it is necessary that the blank should move a sufficient dis-
tance at each closing thereof to allow for the formation of another tooth; this is effected by partially
turning the screw i which moves the carriage or slide j, which is performed as follows:
A spur-wheel k is mounted on the end of the screw i which projects through the bearing; this is not
fixed to the screw, but is allowed to revolve freely thereon, and is furnished with a click pivoted to the
side thereof; this takes into a ratchet affixed to the screw, and therefore as the wheel is turned in one
direction it will carry the screw round with it, but on a reverse motion taking place the click will slip
the teeth of the ratchet; the screw i at the same time remaining stationary. The wheel k has this mo-
tion communicated to it by means of a vertical rack-bar l', being connected by a rod c" to a bell-crank
b", the pendent arm of which is moved by contact of a pin placed in the connecting-rod a", the reaction
heing produced by the weight of the rack-bar. the rise and fall of which may be varied by moving the
position of the pin in the rod a"; thus may the number of indentations produced to a given length of
the blank be regulated according to the requisite degree of fineness of the file.
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The upper end of the rack-bar is connected by a rod m' to the hand lever h', which oscillates on a
fixed fulcrum at k'; this arrangement being for the withdrawal of the teeth of the rack-bar, and thereby
stop the movement of the screw i; but the movement of the hand lever h' at the same time withdraws
the clutch q' from the fly-wheel, and therefore stopping simultaneously the entire action of the ma-
chine. The hand lever h' is connected by the rod 8' to the clutch lever r'; this lever is also connected
by a rod l' to a spring inside the framework, which maintains a permanent pull to withdraw the clutch,
but which is counteracted by a catch on the end of a lever g'; this retains the lever h' in a position for
work, which may be released by hand at pleasure, or the lever g' is tripped up by a projection x' on
the under side of the slide j; at the completion of the teeth, this throws the restraint from the lever h',
and the machine stops. A spur-wheel 1 is mounted on the screw i, which geers into another wheel m,
placed on a longitudinal shaft n; this is turned by a hand-wheel o, and is for the purpose of working the
slide j back, or otherwise adjusting its position before commencing the cut.
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It will be seen by the general arrangement of the geer for moving the slide b', that if the fulcrum on
which the vertical lever p moves were stationary, the space traversed by b' would be the same, but to
allow it to recede as the thickness of the file increases, the lower end of the lever p is jointed to a bent
lever p", attached to a horizontal bar q"; this is fitted in bearings, so as to be capable of movement in
a longitudinal direction, but restrained by the cord 26" with a certain amount of force, which when over-
come by the force required for the cutters ff, the har q" recedes and is retained by a catch f" falling
into the teeth on the end of the said bar; by a complication of levers not seen in the cuts, this catch is
raised at each revolution of the disk x, a pin fixed thereto actuating the levers before mentioned. The
cord u" is wound on a drum placed on the same shaft as the plate t", and cam v"; this cam has
a groove on its periphery, over which a cord c" passes while the cutting is in progress; the cord being
attached at one end to the smallest part of the cam v", is carried thence, and wound on a drum 8", from
80
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FILE AND RASP MACHINE.
the opposite side, while another cord r" supports the lever u, on which hangs the weight v. The force
of this weight is therefore brought to bear on the cam x", with the requisite degree of force to give the
necessary tension to the cord w'; the cord c", as it is gradually wound on the cam, gives, by reason of
the leverage thereof, a greater amount of tension to the cord u", in order to compensate for the loss of
power of the progressive levers c' c', as their range of movement is removed nearer the end of the
machine.
As a further compensation for this loss of power, the weight v, which is hung on the lever и, is grad-
ually moved further from the fulcrum on which one end of this lever is supported, thus increasing the
weight on the cord r" which supports the other end thereof; this is arranged as follows a bar t placed
side by side of the lever u is fitted in slots, cut in the framing 80 as to move in a longitudinal direction,
and is furnished with a sliding piece so, which can be in any position; this piece w has a projection
which takes the suspending rod of the weight v, 80 that any movement imparted to the bar t is trans-
mitted to the weight. A vertical lever h" is pivoted to a fulcrum fixed to the framing; the lower end
of this lever is again connected to a horizontal lever (not seen in the cuts) in such manner as to multi-
ply the movement which is communicated to the bar t. The upper or driving end of the lever h" is
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furnished with a pawl g". pivoted about the middle of its length; one end of the lever falls into the teeth
of a rack v', affixed to the sliding carriage j, and the other has a stud pin which traverses an irregular
slot or guide l", k", i''; the motion imparted to the slide j is thus communicated by the pawl g" to the
lever h", thence to the weight v, altering the position thereof gradually as the cutting progresses. This
motion will continue so long as the stud pin of the pawl g" continues to traverse the horizontal portion
of the guide from i" to k", which will occupy the time necessary for cutting the tapered part of the
file, at the completion of which the stud pin will pass down the incline from k" to l", canting the other
end of the pawl g", consequently withdrawing it from the rack, and preventing any further movement
of the weight on the lever 24, the cutters ff advancing within a uniform distance of each other after
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FILING.
635
that point. Two bearings are raised from the plate be which support a shaft f'; this is furnished with
two screws, one being what is termed a right and the other a left hand thread, corresponding with
screws in the toggles d' d' these are adjusted by the hand-wheel on the end of the shaft 80 as to suit
the thickness of the first cut, commencing at the thinnest part of the blank g. This screw shaft is con-
tinued beyond the bearing at the opposite end from the hand-wheel, and furnished with a ratchet-wheel
q; this is brought into action as the plate t" and cam are gradually turned round, it being connected
thereto by a spring s which depresses one end of a lever r, supported by the framing, the other end car-
rying a pawl, which, when sufficiently elevated by the action of the machine, will be brought into con-
tact with the ratchet q, as it traverses backwards and forwards with the plate b', at each movement
causing the ratchet to turn one tooth, thereby actuating the toggles d' d' in the requisite manner to form
an additional compensation for the loss of power before mentioned in maintaining the requisite amount
of advance of the cutters.
The patentee claims, first, the general arrangement of machinery or apparatus whereby the teeth of
a file or rasp may be cut with great regularity, and on both sides of the said blank at one and the same
time. Secondly, the combination of the cam with this machine, together with the increasing power of
the weight for the purpose of keeping up a compensatory power for the loss occasioned by the decreas-
ing obtuse angle formed by the progressive levers c' c', as the range of their advancing movement is
restricted.
FILING. The use of the file is more difficult than that of the generality of mechanical tools, from
the circumstance of the file possessing, in a very inferior degree, the guide principle, the influence of
which principle, affects all tools, from the most simple cutting tool used by hand, to the most complex
outting machine or engine.
Commencing with the position of the work, it is in all cases desirable that the surface to be filed
should be placed horizontally, and the general rule for the height of the work above the ground is, that
the surface to be filed should be nearly level with the elbow joint of the workman. Some latitude is,
however, required in respect to the magnitude of the works, as when they are massive, and much is to
be filed off from them, it IS desirable that the work should be a trifle lower than the elbow when the
work is minute and delicate, it should be somewhat higher, so that the eye may be the better able to
add its scrutiny to that of the sense of feeling of the hand, upon which, principally, the successful prac-
tice depends.
It is apparent that the most direct way of producing a flat surface with the file, would be to select
a file the face of which was absolutely flat, and that should be moved in lines absolutely straight; but
there are certain interferences that prevent these conditions being carried out. First, although it is de-
sirable to employ files that are as nearly straight as possible, and that are also fixed straightly in their
handles, yet very few files possess this exactitude of form, and although in the attempt to obtain this
perfection, some files are planed before being cut with teeth, still the cutting and the hardening 80 far
invalidate this practice, that few even of these planed files can retain their perfect straightness. There-
fore, as it may be almost taken for granted that no files truly possess the intended form, it is better
purposely to adopt that kind of irregularity, which the least interferes with the general use of the in-
strument.
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1649.
1651.
1652.
1650.
1653.
The file, if concave or hollow in respect to its length, in the manner coarsely exaggerated in Fig. 1649,
might be used for works of corresponding convexity; but it would be impossible to file a flat surface
therewith, as the concave file would only touch the surface at its edges, but the convex side of the same
file might, as in Fig. 1650, be made to touch any and every part of the surface if moved in a right line.
On this account most files are made thicker and wider in the middle, or with both faces convex, and the
error of hardening will then rarely make either side concave, but will leave both faces convex, although
differently so; and consequently, both sides, notwithstanding some irregularity, are usable upon flat
works, provided the operator can move them in a right line across the work.
It might be urged that the file, from being itself in the form of the are of a large circle, would reduce
the work to the counterpart form; it is true this is the tendency, and may by dexterity become the
result, even on narrow pieces; but the contrary error is more common, 80 that the surface of the work
becomes rounded instead of concave or plane.
The file held in the two hands upon the narrow work, may be viewed as a double-ended lever, or as
a scale-beam supported on a prop; and the variation in distance of the hands from the work or prop
gives a disposition to rotate the file upon the work, and which is only counteracted by habit or ex-
perience.
Assuming, for the moment, that in the three diagrams the vertical pressure of the right hand at r,
and the left at 1, to be in all cases alike, in Fig. 1651, or the beginning of the stroke, the right hand
would, from acting at the longer end of the lever, become depressed; in Fig. 1652, or the central posi-
tion, the hands would be in equilibrium and the file horizontal and in Fig. 1653, or the end of the stroke,
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FILING.
the left hand would preponderate; the three positions would inevitably make the work round, in place
of leaving it plane or flat.
It in true the diagrams are extravagant, but this rolling action of the file upon the work is in most
cases to be observed in the beginner; and those practised in the use of the file have, perhaps uncon-
sciously, acquired the habit of pressing down only with the left hand at the commencement, and only
with the right hand at the conclusion of every stroke; or negatively, that they have learned to avoid
swaying down the file at either extreme, and which bad practice will necessarily result, if the operator
have not at first a constant watch upon himself, to feel that the file and work are always in true con-
tact, throughout the variable action of the hands upon the instrument.
The work, when small, is almost invariably held on the filing-block with the left hand, occasionally
through the intervention of a hand-vice, Fig. 1657. In this case the two hands act in concert, the right
in moving the file, the left in adjusting the position of the work, until the individual is conscious of the
agreement in position of the two parts.
1654.
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Sometimes indeed the partial rotation of the work, in order to adapt the work to the file, is especially
provided for, so as to compensate for the accidental swaying of the file; such is the case in the various
kinds of swing tools, used by watchmakers in filing and polishing small flat works. A similar end is more
rarely obtained, on a larger scale, when the file is required to be held in both hands. For example,
filing-boards resembling Fig. 1654, and upon which the work is placed, have been made to move on
two pivots, somewhat as a gun moves on its trunnions; consequently the works, when laid upon the
swinging board, assume the same angle as that at which the file may at the moment be held.
A more common case is to be seen in filing a rectangular mortise, through a cylindrical spindle, as in
Fig. 1655; the hole is commenced by drilling three or four holes, which are thrown into one by a cross-
cut chisel, or small round file; and the work, when nearly completed, is suspended between the centres
of the lathe, 80 that it may freely assume the inclination of the file. At other times, the cylinder is laid
in the interval between the edges of the jaws of the vice, that are opened as much as two-thirds the
dinmeter of the object, which then similarly rotates on the supporting edges; this mode is shown in
Fig. 1656.
These three applications are objectionable in some instances, as the file is left too much at liberty,
and the works are liable to be filed hollow instead of flat. especially if the file be rounding, because the
unstable position of the work prevents the file from being constrained to act on any particular spot that
may require to be reduced.
After a file has been used for wrought-iron or steel, it is less adapted to filing cast-iron or brass, which
require keen files; therefore to economize the wear of the instrument. it is used for a time on brass or
cast-iron, and when partially worn, it is still available for filing wrought-iron or steel; whereas, had the
file been first used on these harder materials, it would have been found comparatively ineffective for
brass and cast-iron.
As a further measure of economy, the pressure on the file should be always relieved in the back
stroke, which otherwise only tends to wear down or break off the tops of the teeth. as their formation
shows that they can only cut in the ordinary or advancing stroke; the file should, in consequence, be
nearly lifted from the work in drawing it back, but it is not usual actually to raise the file off the work,
as it then becomes needful to wait an instant before the next stroke, to ensure the true position of the
file upon the work being resumed; whereas, if it is brought back with inconsiderable pressure, the file
is not injured, and the hand still retains the consciousness of the true contact of the file and work, with-
out which the instrument is used with far less decision and correctness than it otherwise would be.
Some workmen smooth the work by the method called draw-filing, or by drawing the file sideways
along the work. using it in fact as a spoke-shave instead of a file. Another mode sometimes employed
is to curl the work with the file, by describing small circles with the instrument as in grinding or pol-
ishing, but neither of these practices employs the file teeth in the mode in which they are legitimately
adapted to cut, and no great reliance should be placed upon them. When smooth surfaces are required,
it is better, as the work advances towards completion, to select files that are gradually finer, but always
to use them from point to heel.
When it is desired to make the smooth files cut wrought-iron, steel, and other fibrous metals very
smoothly, the file is used with a little oil to lubricate the surface, 80 that it may not penetrate to the
same degree as it would if used dry.
The particles removed from the materials operated upon, are always more or less liable to clog the
file, but which, particularly when the instrument is dry. are partially removed by giving the edge of the
file a moderately smart blow on the chaps of the vice or the edge of the bench; but particles of wrought-
iron, steel, and other fibrous metals, are apt to pin the file, or to stick in so hard as to require to be
picked out with a pointed steel wire, which is run through the furrow in which the pin is situated.
Files are sometimes cleaned with a scratch-brush. which is a cylindrical bundle of fine steel or brass
wire, bound tightly in its central part, but allowing the ends of the wire to protrude at both extremities
as a stiff brush. Occasionally also, a scraper is used, or a long strip of sheet brass, about an inch wide,
a small portion of the end of which is turned down at right angles, and thinned with a hammer; the
thin edge is then drawn forcibly through the oblique furrows of the file, and serves as a rake to remove
any particles of metal that lodge therein.
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But the best and most rapid mode of cleaning the file, is to nail to a piece of wood about two inches
wide, a strip of the so-called cotton card, which constitutes a most effective brush, and answers the pur-
pose exceedingly well. Some workmen, to lessen the disposition of the file to hold the file dust, or
become pinny, rub it over with chalk; this absorbs any oil or grease that may be on the file, and in a
considerable degree fulfils the end desired.
To remove wood-dust from files, floats, and rasps, some persons dip them for a few moments into hot
water, and then brush them with a stiff brush. This plan, although effective, is neither general nor
important.
The principal methods of fixing works. in order to subject them to the action of the file, will be no-
ticed under the heads, Vice, Tail-vice, and Vice-bench. However, many of the massive parts of machi-
nery are 80 heavy, that gravity alone is sufficient to keep them steady under the action of the file, and
for such as these, it is therefore only needed to prop them up in any convenient manner.
A great number of small works are more conveniently filed, whilst they are held with the left hand,
the tile being then managed exclusively with the right; this enables the artisan more easily to judge of
the position of the tile. In such cases, a piece of wood f, Fig. 1657, called a filing-block, is fixed in the
table or tail-vice.
Pieces that are sufficiently long and bulky, are held upon the filing-block by the hand unassistedly:
but small and short works are more usually fixed in some description of hand-vice, and applied in the
position shown in Fig. 1657, and the vice being larger than the work, serves as a handle, and affords a
better grasp.
For works of larger size the hand-vices are progressively larger, as in Fige. 1658 and 1659; some of
them have wooden handles. Almost all the hand-vices have fly nuts to be twisted with the fingers,
but the most powerful, which sometimes weigh as much as about three pounds, have square nuts that
are fastened by a key or spanner 8.
Hand-vices are not, however, in all cases employed; but small wires and other pieces are also held
in a species of pliers, Fig. 1660. called pin-tongs, or sliding-tongs, which are closed by a ferule that is
drawn down the stem. Fig. 1661 shows another variety of this kind, that has no joint, but springs open
by elasticity alone when the ring r is drawn back.
1657.
1658.
1659.
1660.
1661.
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The small pin-vice, Fig. 1657, is used by watchmakers in filinz up small pinz and other cylin !rical
objects; the jaws are not united by a joint, but are formed in one piece with the stem of the vice, the
end that constitutes the jaw being divided or forked; the screw an I stem are e ich perforated thro ugh-
out. that the en Is of long wires may be file 1: all I the stem is octang dar that the pin-vice may be
readily twis'ed to and fro. This is more usuil in the D BITTOW vices, Fig. 1658, known as dog-nose or pig-
more hand-vices, then in those with wi le or cross chaps. Figs. 1637 and 1659.
Many circular works that were formerly thus filed, are now, from motives of expedition and accu-
racv. more commonly execute I in the turning-lathe, since the great extension in the use of this mit-
chine. which has become nearly as general a: the vice or the file itself; but frequent occasions still
remain in which the hand vice an 1 file are thus employed.
In the pin-tong³. Fig 1681, besi les the facility of turning the instrument round with the fingers,
from the rever-e end having a cen're and pullev, the same spring tongs serve conveniently no forceps
for holding small drills to be worke.l with the drill-bow and also for other purpo e' in watch work.
Numerous flat works are ton large, thin. and irregular in their superᶜcie+ to admit of being fixed
in the various kinds of bench-vice: as there would be risk of bending such thin pieces by the pressure
of the vice applied against the edges of the work.
The largest flat works are simply laid on the naked surface of the work-bench, and temporarily
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FILING.
held by half a dozen or more pins or nails driven into the bench. The pins should be as close to
the margin as possible, and yet below the surface of the work.
For thin flat works of smaller size, the filing-board, Fig. 1662, is a convenient appendage; it measures
six or eight inches square, and has a stout rib on the under side, by which it is fixed in the vice.
In filing thin flat works, such as the thin handles or scales of penknives and razors, and the this
steel plates used in pocket-knives, cutlers generally resort to the contrivance represented in Fig. 1663,
and known as a patting-vice.
1662.
1063.
One face of the small filing-block f, Fig. 1657, is also used for very small thin works, and which are
prevented slipping from the file by the wooden ledge, or by pins driven in. In many instances, also,
thin works are held upon a piece of cork, beneath which is glued a square piece of wood, that the
cork may be held in the vice without being compressed. The elasticity of the cork allows the work
to become somewhat imbedded by the pressure of the file, between which and the surface-friction it
is sufficiently secured for the purpose without pins.
Before any effective progress can be made in filing flat works, the operator must be provided with
the means of testing the progressive advance of the work; he should therefore possess a true straight-
edge and a true surface-plate. The straight-edges used by smiths are generally of steel, and although
they have sometimes a nearly acute edge, it is much more usual to give them moderate width thus,
in steel straight-edges from one to four feet in length, the width of the edge is from one-sixteenth to one-
fourth of an inch, and in cast-iron straight-edges from six to nine feet in length, the width is usually two
to three inches.
The straight-edge is used for trying the surface that is under correction, along its four margins, across
its two diagonals, and at various intermediate parts, which respective lines, if all exact, denote the
surface to be correct; but the straight-edge alone is a tedious and scarcely sufficient test, and when
great accuracy is desired, it is almost imperative to have at least one very exact plane metallic surface
or surface plate, by which the general condition of the surface under formation may be more quickly
and accurately tested at one operation; and to avoid confusion of terms, it is proposed in all cases,
when speaking of the instrument, to employ the appellation planometer, which is exact and distinctive.
The flat piece of cast-iron intended to be operated upon, having been chipped all over, a coarse hand-
file, of as large dimensions as the operator can safely manage, is selected, and in the commencement
the rough edges or ridges left by the chipping chisel are levelled, those parts however being principally
filed, that appear from the straight-edge to be too high.
The strokes of the file are directed sometimes square across as on a fixed line, or obliquely in both
directions alternately; at other times the file is traversed a little to the right or left during the stroke,
no as to make it apply to a portion of the work exceeding the width of the file. These changes in the
applications of the file are almost constantly given, in order that the various positions may cross each
other in all possible directions, and prevent the formation of partial hollows. The work is tried at short
intervals with the straight-edge; and the eye directed on a level with the work to be tested, readily
perceives the points that are most prominent. After the rough errors have been partially removed, the
work is taken from the vice and struck edgeways upon the bench to shake off any loose filings, and it
is then inverted on the planometer, which should be fully as large or larger than the work. As, how-
ever, it cannot be told by the eye which points of the work touch the planometer, this instrument is
coated all over with some coloring matter, such as pulverized red chalk mixed with a little oil, and then
the touching places become colored.
The work is slightly rubbed on the surface plate, and then picks up at its highest points some of the
red matter; it is refixed in the vice, and the file is principally used in the vicinity of the colored parts,
with the occasional test of the straight-edge, and after a short period the work is again tried on the
planometer.
This process is continually repeated, and if watchfully performed it will be found that the points of
contact will become gradually increased.
The grooved or roughing-out cutter is employed in the commencement, because it more rapidly pene-
trates the work, and a few strokes are given to crop off the highest points of the surface; the furrows
made by the serrated cutter are then nearly removed with the file, which acts more expeditiously
although less exactly than the plane, and in this manner the grooved plane iron and the coarse file are
alternately used. In the absence of the planometer, the metal plane assumes a greatly increased
degree of importance.
As the work becomes gradually nearer to truth, the grooved cutter is exchanged for that with a con-
tinuous or smooth edge a second-cut, or bastard file, hand is also selected, and the same alternation of
planing and filing is persevered in, the plane serving as it were to direct the file, until it is found that
the plane iron acts too vigorously, as it is scarcely satisfied with merely scraping over the surface of the
cast-iron'; but when it acts it removes a shaving having a nearly measurable thickness, and therefore,
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although the hand-plane may not injure the general truth of the surface, it will prevent the work from
being so delicately acted upon, as the continuance of the process now demands; a smoother hand file is
consequently alone employed in furthering the work.
If the piece of cast-iron should have been turned in the lathe, or planed in the planing machine,
instead of having been wrought entirely with the chipping chisel, plane, and file, the former instructions
would be uncalled for, as the remaining steps alone would remain to be followed.
It is now often usual to discontinue the use of the file, and to prosecute the work with a scraper,
which having a sharp edge, instead of a broad and abrading surface, may be made to act with far more
decision, on any, even the most minute spot or point. A worn-out triangular file, ground at the end on
all the faces, so as to make thin keen edges, is generally used as the scraper; this should be keenly
sharpened on an oil-stone, so as to act without requiring much pressure, which would only fill the work
with strise or utters.
In producing metallic surfaces the constant effort should be to reduce all the high places with as
much expedition as circumstances will admit, but avoiding, on the other hand, that energetic use of the
tool, which may too hastily alter the condition of the surface, and in expunging the known errors, induce
others equal in degree but differently situated. Throughout the work, attempt should be made to keep
the points of bearing, whether few or many, as nearly equidistant as may be, instead of allowing them
to become grouped together in large patches.
The periods of alternation between the hand-plane and the file, and also the times when these are
successively rejected, in favor of the scraper as the finishing tool, must be in great measure left to the
judgment of the operator.
There should be a frequent examination of the work by means of the straight-edge and planometer,
which latter should at all times be evenly tinted with the color.
It is not to be supposed that it is in every case needful to proceed in the careful and progressive
mode just described, as the parts of different works require widely different degrees of perfection as to
flatness. For instance, in many it is only necessary they should be clean and bright, and have the
semblance of flatness; with such, even the straight-edge is little if at all used as a test. Those surfaces
by which the stationary parts of framings are attached, require a moderate degree of accuracy, such as
may be comparable with the perfection in the hewn stones of a bridge, which require to be flat, in order
that they may bear fairly against each other, as without a certain degree of truth, the stone might
break from the unequal strain to which it would be exposed.
The flat parts of metallic works, if similarly imperfect, would bend, and perhaps distort the remainder
but although it is of great importance that bearing surfaces should be out of winding, or not twisted, it
is by no means important that such bearing surfaces should be continuous, as a few equally scattered
bearing points frequently suffice. Thus it was the common practice before the general introduction of
the planing machine, to make fillets around the margin of the bearing surfaces of castings, which fillets
alone were corrected with the chisel and coarse file, for the juxtaposition of the larger pieces or frame-
work of machines, the intermediate spaces being left depressed and out of contact. This mode sufficed,
provided the pressure of the screw-bolts could not, by collapsing the hollow places, distort the castings,
with which view chipping places were also generally left around the bolt-holes of the work: this method
greatly reduced the labor of getting up such works by hand; but fillets and chipping places are now in
a great measure abandoned. Smaller and more delicate works, requiring somewhat greater accuracy
than those just described, are left from smoother files, but in most cases without the necessity of
scraping; but the rectilinear slides and moving parts of accurate machinery, and the trial or surface-
plates of the mechanician, require beyond all other works the most dexterous use of the file.
Until very recently, when the points of bearing had been so multiplied by the file and scraper, as not
to exceed about half an inch in average distance, and that a still higher degree of accuracy was desired;
it was the ordinary practice to attempt the obliteration of these minute errors by the method of
grinding.
That two surfaces which are very nearly accurate, if ground together for a very short time, do in some
degree correct each other, is true, but it has been long and well known, that a continuance of the
grinding is very dangerous, and apt to lead the one surface to become convex, and the other concave in
a nearly equal degree, and on this account three pieces were usually operated upon that the third might
act as an umpire, as although two pieces possessing exactly opposite errors may appear quite to agree,
the third cannot agree with each of these two until they have all been made alike, and quite plane
surfaces.
But the entire process of grinding, although apparently good, is 80 fraught with uncertainty, that
accurate mechanicians have long agreed that the less grinding that is employed on rectilinear works
the better.
A further and equally important advantage results from the discontinuance of grinding, as regards the
slides and moving parts of machinery. Some of the grinding powder is always absorbed in the pores
of the metal, by which the metallic surfaces are converted into species of laps, 80 that the slides and
works carry with them the sources of their depreciation and even destruction.
The former instructions have been restricted to the supposition that only one of the superficies of the
work was required to be made plane or flat; but it frequently happens in rectangular works, such as
the piece A BC, Fig. 1664, that all six surfaces, namely, the top and bottom A a, the two sides Bb, and
the two ends C c, all require to be corrected and made in rectangular arrangement, (the surfaces a b c
being necessarily concealed from view,) and therefore some particulars of the ordinary method of pro-
ducing these six surfaces will be added.
The general rule is first to file up the two largest and principal faces A and a, and afterwards the
smaller faces or edges Bb, and Cc. The principal faces A a, especially when the pieces are thin, must
be proceeded with for a period simultaneously, because of the liability of all materials to spring and
alter in their form with the progressive removal of their substance, and on this account the work,
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FILING.
whether thick or thin, is frequently prepared to a certain stage at every part, before the final correction
is attempted of any one part.
The straight-edge and surface-plate are required to prove that each of the faces A and a is a plane
surface, and the callipers or a similar gage is also needful. to prove them to be in parallelism. Calli-
pers, unless provided with set screws, are very liable to be accidentally shifted, and it is needful to use
them with caution, otherwise their elasticity, arising from the length of their legs, is apt to deceive.
There are gages, such as Fig. 1665, with short parallel jaws that open as on a slide, and are fixed by a
side screw; and a still more simple and very safe plan is to file two rectangular notches, in a piece of
sheet-iron or steel, as in Fig. 1666, the one notch exactly of the finished thickness the work is required
to possess, the other a little larger to serve as the coarse or preliminary gage.
1654.
1665.
1666.
K
c
B
Sometimes the one face of the work, or A, having been filed moderately flat, a line is scored around
the four sides of the work with a metal marking-gage, the same in principle as the marking-gage of the
joiner. At other times the corrected face A is laid on a planometer larger than the work, and the
marginal line is scribed on the four edges by a scribing point p, Fig. 1664, projecting from the sides of
a little metal pedestal that bears truly on the surface-plate.
Chamfers or bevelled edges are then filed around the four edges of the face a, exactly to terminate
on the scribed lines: the central part of a can be reduced with but little watchfulness, until the marginal
chamfers are nearly obliterated. This saves much of the time that would be otherwise required for
investigating the progress made; but towards the last, the callipers and planometer must be carefully
and continually used, to assist in rendering A and a at the same time parallel and plane surfaces.
The two principal edges Bb are then filed under the guidance of a square; the one arm of the square
is applied on A or a at pleasure, as in joinery work; or if the square have a thick back it may be
placed on the planometer, as at 8, Fig. 1664; if preferred, the work may be supported on its edge B
upon the planometer, and the back square also applied, as at 8, in which case the entire length of the
blade of the square comes into operation, and the irregularities of the plane B are at the same time
rendered obvious by the planometer.
Another very convenient test has been recommended for this part of the work, namely. a stout bar,
such as r, Fig. 1664, the two neighboring sides of which have been made quite flat and also square with
each other. When the work and trial-bar are both laid down, the one side of the bar presents a truly
perpendicular face, which may, by the intervention of coloring matter. be made to record on the work
itself, the points in which B differs from a rectangular and vertical plane.
When the edge B has been rendered plane and square, the opposite edge b may in its turn be
marked either with the gage or scribing-point at pleasure; the four edges of b may be then chamfered,
and the entire surface of b is afterwards corrected, (as in producing the second face a,) under the
guidance of the square, callipers, rectangular bar, and surface-plate, or some of these tests.
The ends Cc now claim attention, and the marginal line is scribed around these by the aid of the
back square alone; but the general method 60 closely resembles that just described as not to call for
additional particulars.
Should one edge of the work be inclined, or bevelled, as in the three following figures, in which the
works are shaded, to distinguish them from the tools, the rectangular parts are always first wrought,
1669.
1670.
1667.
1668.
1672.
1674.
1671.
1673
and then the bevelled edges, the angles being denoted by a bevel instead of a square; either with a
bevel having A movable blade, Fig. 1667, or by a bevelled templet made of sheet metal. as in Figs 1668
or 1669, which latter cannot get misadjusted. The bevelled edge of the work is also applied if possible
on the planometer; in fact, the planometer and bevel are conjointly used as the testa Bevelled works
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are either held in the vice by aid of the chamfer-clamps, or they are laid in wooden troughs, with
grooves so inclined, that the edge to be filed is placed horizontally. Triangular bars of equilateral sec-
tion are thus filed in troughs, the sides of which meet at an angle of 60 degrees, as in Fig. 1670.
The succeeding examples of works with many plane surfaces are objects with rebates and grooves,
as represented in Figa. 1671 to 1674. Pieces of the sections. Figs. 1671 and 1672, supposing them to
be short, would in general be formed in the solid, either from forgings or castings, as the case might be;
the four exterior and more accessible faces would be filed up square and true, and afterwards the
interior faces, with a due regard to their parallelism with the neighboring parts, just after the mode
already set forth. The safe-edge of the file is now indispensable: as in filing the face b the safe-edge
of the file is allowed to rub against the face a of the work. and which therefore serves for its guilance;
and in filing the face a the side b becomes the guide for the file. The groove in Fig. 1672 requires a
onfe-edge square file.
When, however, pieces of these sections, but of greater lengths, have to be produced by means of the
file alone, it is more usual to make them in two or three pieces respectively, as shown detached in Figs.
1673 and 1674 and which pieces are first rendered parallel on their several edges, and are then united
by screws and steady pins.
In works of these kinds, which have rebates, grooves, internal angles, or cavities, the square, with a
sliding blade, shown in Fig. 1672, is very useful, as the blade serves as a gage for depth, besides acting
as a square, the one arm of which may be made of the precise measure of the edge to be tried. This
instrument is often called a turning square, as it is particularly useful for measuring the depth of boxes
and other hollowed works turned in the lathe.
In making straight mortises, as at 88, Fig. 1675, unless the groove is roughly formed, at the forge, or
in the foundry, it is usual to drill holes nearly as large as the width of the mortise, and in a straight
line; the holes are then thrown into one another by a round file, or a cross-cutting chisel, and the sides
of the mortise are afterwards filed square and true.
$
1676.
1675.
:
For R circular mortise cc the mode is just the same, with the exception that the holes are made on a
circular line; and that, instead of a flat file being used throughout, a half round or a crossing file is
used for the concave side of the mortise.
Short rectangular mortises, or those which may be rather considered to be square holes, as in Fig.
1676, would, if large, be prepared by forging or casting the material into the form; and then the SIX
exterior fuces having been corrected, the aperture would be filed on all sides under guidance of some
of the various tests before referred to. And in such a case it is convenient to employ a small
square 8, in the form of a triangle, to which is attached a wire that may serve as a handle,
whereby the square may be applied at any part within the mortise without the sight of the workinan
being intercepted by his own fingers. Sometimes also a cubical block filed truly on four of its faces to
the exact dimensions of the aperture, is used as a measure of the parallelism and flatness of the four
interior faces.
The method first to be described is one that is considerably used in thick pieces of metal, for making
holes differing from the circular form, such as square, hexagonal, triangular, elliptical, and other holes,
by first drilling a round hole, and then enlarging and changing the section of the circular hole by a taper
punch. better known as a drift, which tool is made of steel, and exactly of the same section as that
required in the hole; the drift is hardened and tempered before use.
The drift for a taper square hole is made as in Fig. 1677, or simply as a square pyramid, considerably
longer than the hole required; a round hole is first drilled in the work, just large enough to admit the
small end of the drift, which is then driven in; its angles indent and force out the metal, making it first
like the magnified line m, and ultimately exactly square, unless by mistake the hole were drilled too
large, when the circular parts would not be quite obliterated. If admissible, the endlong blows on the
drift are mingled with a few blows on the sides of the work, as at bb, or parallel with the sides of the
drift, which cause the metal to adapt itself more readily to the tool. The drift must not, however, be
used too violently, for as it acts as a wedge, it may burst open the work. and which latter is therefore
mostly left strong and rough before being drifted; and generally, when the angles have been somewhat
indented. they are partly filed out, and completed by the alternate employment of the file and drift,
the marks made by the latter serving continually to in licate the parts to be removed with the file.
Taper square holes, such as those in the chucks for drills, are made with some facility. The chuck is
first drilled on its own mandrel, and the drift is put in the four different ways in succession, that the
errors incidental to its form may be scattered and lost; the chuck is also placed on the mandrel at
intervals. with the drift in its place, that the drift may show, as it revolves, whether or not the hole is
concentric. When it is required that the drifted hole should be parallel instead of taper, the drift is
81
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FILING.
made as in Fig. 1678; that is, parallel for a short portion in the middle of its length, and the extremities
alone are tapered 80 as to make the tool smaller at each end; the work is therefore first gradually
enlarged to admit the largest part of the drift, and the parallel part is then driven through the work,
and renders the inner surface of the same a true counterpart of the drift, if proper care have been taken.
In some few cases the sides of the drifts are notched with a file, 80 as to act as teeth; but this is not
general.
When drifts are used, the interior surfaces are often completed before the exterior. The holes are
first drifted whilst the work is larger than its intended size, and afterwards the exterior part is filed or
turned, as the case may be, from the hole, that is, the hole is made the basis of the measurement of the
exterior portions of the work.
In making by hand the key-ways in the round holes of the wheels, it is to be observed, that it is
common to turn a cylindrical plug exactly to fill the hole, and to make a notch in the plug as wide as
the intended key-way and parallel with the axis; the plug is shown at g, Fig. 1679. A piece of steel f
is then filed parallel, and exactly to fit the
1678.
notch, and its edge is cut as a file, and used as
such within the guide-block, the latter being at
the time inserted in the hole of the wheel. In
this case the block becomes the director of the
1679.
file, and the notches in any number of wheels
are made both parallel and axial, and the only
precaution that remains to be observed is in the
g
depth of the notches, and this is not always im-
1677.
portant; the depth may however be readily de-
termined by making the grooves at first a little
shallower than their intended depth, and then,
4
m
the plug having been removed from the hole, a
s
f
stop is attached to the side of the file, parallel
with its edge, as at 8, to prevent its penetrating
beyond the assigned depth.
In filing works that are convex, flat files are always used, and the file is necessarily applied as a
tangent to the curve; and in filing concave works round and half-round files are used, and in some
-cases they are selected, nearly or exactly as counterparts of the hollows to be wrought.
The manipulation of the file upon curvilinear works is entirely different from that required to produce
a plane surface, in which latter case the work is held at rest and the hands are moved as steadily as
possible in right lines; but in filing curved works an incessant change of direction is important, and 80
far as practicable, either the file, or the work, is made to rotate about the axis of the curve to be
produced.
A semicircular groove of half an inch radius, as in Fig. 1680, would be most easily filed with a round
file of nearly the same curvature, and the correspondence between the file and work, and consequently
of their axes likewise, would render the matter very easy; but the file, from the irregularity of its
teeth, would leave ridges in the work, unless in every stroke it were also twisted to and fro axially by
the motion of the wrist, and occasionally in the reverse direction, 80 that the furrows made by the teeth
might cross each other. If the groove to be filed had a diameter of three or four inches, although the
file might be selected to correspond in curvature with the groove, as it would not embrace the entire
hollow, the twisting and traversing of the file would be imperative in order to arrive at all parts of the
work.
1680.
1681.
1682.
b
Under ordinary circumstances it is certainly best that the curvature of the file and work should agree
as nearly as possible: but it is obvious that the file, if more convex than the work, can only touch the
latter at one part, as at a, Fig. 1681; whereas, if the file is less convex, or flatter, than the work, it will
act at two places, as at bb, Fig. 1682. Cutlers, in filing out the bows of scissors, always avail them-
selves of this circumstance, and until nearly the conclusion, use files flatter or less convex than the work.
In filing concave works, there is but little choice of position, as the file is always parallel with the
axis of the curve, as in the dotted line in Fig. 1683; but in convex works, such as Fig. 1684, the file may
be applied either parallel with the axis as at pp, or transversely thereto as at tt. In general, how-
ever, the work would be fixed obliquely as in Fig. 1685. and the file would be first used transversely
for some one or two strokes, at an inclination of about 30 degrees with the horizontal line, as at a. 80 as
nearly to agree with the straight side of the object: the file would be successively raised to the horizon-
tal, and depressed in the same degree on the other side; in fact. proceeding through the positions a be,
Fig. 1685, at some eight or ten intervals. and which would tend to make as many insignificant ridges
upon the work. The ridges would be then melted together by swinging the hands from the position
a to c in every stroke, to be repeated a few times; but as the entire semicircle could not be embraced
at one stroke, the work would be re-fixed in two or more positions, $0 as to divide the operation into
about three stages.
A more exact although less energetic method would be to place the file parallel with the axis, as on
pp, Fig. 1684, and to sweep round the curve principally by the twisting motion of the wrist. A third
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mode, frequently adopted in such small pieces as can be held upon the filing-block with the hand-vice,
is to swing the work upon its axis, and to use the file with the right hand, as if on a flat surface.
Some works are curvilinear in both directions, such as curved arms and levers with rounded edges;
many of these kinds are completed by draw-filing them, or rubbing the file sideways or laterally around
the curve, instead of longitudinally as usual. The great majority of curved works are moulded and
formed prior to the application of the file, which is then principally used to smooth and brighten them-
other works are shaped almost entirely with the file, assisted by outlines drawn on the pieces them-
selves-and again other works are shaped with the file, under the guidance of templets or pattern-plates
of hardened steel. Some observations will be offered on all three of these modes.
t
1684.
1685.
1633.
b
P
Firstly, in respect to filing up metal works that have been accurately shaped by founding or forging,
little or nothing remains to be added, as the only object is to act on every part of curvilinear surfaces
in the most expeditious and commodious manner, with the general aim of reducing any trifling errors
of form that may already exist in them, and avoiding the introduction of new ones; which circumstances
call for the frequent scrutiny of the eye, and an incessant yet judicious variation in the position of the
hands.
Secondly, curved works that are moulded or formed almost entirely with the file. These are blocked
out square, and the outlines of the curves are drawn on the ends and sides of the pieces, to guide the
file in a manner analogous to the routine pursued by carpenters, masons, and other artisans. For in-
stance, to form a bend, as in Fig. 1686, the work is prepared of a nearly rectangular form, and the half
circle having been drawn at each end, the angles of the works are coarsely removed about 45 de-
grees, making the end a semi-octagon; sometimes the four angles are farther reduced, giving to the
work eight facets, prior to their being thrown together in making the general curve. If these sides are
made with only a very moderate degree of exactness, they will greatly tend to preserve the uniformity
of section throughout.
1686.
1688.
"
1687.
u
c
b
b
a
Many workmen, when they have removed the two principal angles at 45 degrees, make a chamfer
entirely around the semicircle at each end, to guide the file in hastily reducing the principal bulk of
the material. It is also desirable that the straight-edge should be frequently applied along the axis of
the curve, at various parts, during the progress of the work.
Should the entire piece, Fig. 1687, have to be made from a solid block, two cuts a and b, made with
the saw, would remove the corner. The round part of the bead would be made as before, and previous
to filing the hollow, it would be chamfered on the line c; a half-round file, of less curvature than the
hollow itself, would be first sunk in the middle of the chamfer, and the hollow would be deepened and
extended sideways, always maintaining an easy curve, until it reached the marginal lines where the
hollow meets the plane surfaces.
Where hollows run on to right lines as at a, Fig. 1688, there is some risk of making a break in the
junction, either from the curve sinking below the right line, as at b, or from the straight line, as at c,
advancing too far and breaking in upon the curve. On this account a break or fillet is usually made at
the part as at d. or el«e it is usual primarily to give that form. by filing the flat first, and then sinking
down the hollow just to meet it, an.l at the conclusion letting the half-round file run a little way on to
the right line. Some, bowever, prefer the opposite course. or that of sinking the hollow to its full depth,
and then filing down the remainder with the flat file, but which mode is certainly attended with more
risk.
Thirdly, curved works that are shaped with the file under the guidance of templets or pattern-plates
of hardened steel This mode is much followed in works of two principal kinds, namely, thin works re-
quired in great numbers and precisely of one form, and in a variety of works that require to be exactly
circular, although they may not admit of being 80 fashioned in the lathe.
Many thin works of the first kind are stamped or punched out of the sheet metals, as for instance,
the washers for machinery, the links of jointed chains, steel pena, parts of locks for joinery. and numer-
ous other thin work<; but many objects of larger kinds, and that are not wanted in such large numbers,
are not stamped, but are either cn-t. or cut out with the shears, and afterwards filed between templets.
The snail-wheel of a striking clock, Fig. 1689, is frequently thus formed, by means of a templet: it
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FILING.
has an edge formed in twelve steps. arranged spirally, the positions of which determine the number of
strokes of the hammer on the bell. In this case, which will serve as a general example, a piece of
sheet-steel is cut out, flattened, and smoothed on one side, to receive the drawing of the snail-wheel, and
a second piece is also prepared. The two are first drilled together with a central hole, and another
hole as distant from the centre as admissible. The two plates are then united by two pins, and the
outline of the work having been drawn on one of them, they are next filed in steps carefully to the
lines, and square across the edges, and they are afterwards hardened and slightly tempered to lessen
their liability to fracture on being pinched in the vice. The dozen or more snail-wheels having been
cast, or cut out of sheet-brass, and flatened with the hammer, two or three at a time are pinched along-
side one of the templets, whilst the two pin-holes are made with the breast-drill or in the lathe, with a
drill that exactly fits the holes in the templets. It only remains to place the dozen plates between the
templets, keeping them in position by two pins extending through the whole number, and then all the
notches are filed in the brass plates, until the file very nearly touches the steel patterns, as absolute
abrasion on the steel itself would greatly injure the files. In this mode the several brass plates become
very exact copies of the pattern.
Templets are as much used for setting out and producing series of holes in any special arrangement,
as in filing works to any particular form a complex example of templets being used in this manner, is
in drilling the side plates of harps intended for the arbors and link-works, used in temporarily shorten-
ing the strings. The respective positions of the holes in these side plates require a most exact arrange-
ment. any departure from which, would prevent that precise shortening of the string required to pro-
duce the semitones with critical accuracy, and would also cause an unbearable jar, unless the cranks of
the harp were severally in true position, or on the lines of centres, 80 as firmly to support the tension of
the strings under all circumstances.
A different application of templets is sometimes met with in filing up numerous similar parts in the
same object, as the arms or crosses for the wheels of clocks and other machines. The exact pattern of
one spoke is filed up as a templet, which is shaded in Fig. 1690, and serves for the similar configuration
of every spoke; the position of the templet being given by a central pin, aided by any little contrivance
which catches into the 3, 4, 5, or 6, equidistant teeth corresponding with the number of arms.
It frequently happens that certain forged, cast, and other works have parts, known as bosses, swells,
collars, and knuckles, that are pierced with holes, which require their flat surfaces and also their mar-
gins to be made partially or entirely concentric with the holes. When such parts occur as bosses, they
often project from a flat surface, and after the central hole is drilled, some of the pin-drills, or analogous
tools used in drilling machines, are employed in finishing the margins.
1689.
1690.
a
1691.
When the circular margins are discontinuous, files and templets are more or less require 1: thus the
extremity of a forged arm, such as Fig. 1691, is drilled. and in the configuration of the remaining parts,
if but one or two such pieces are to be m lile, a bois or plug of wood is turned like a, that shall fit the
hole; the shoulder of the wood is then rubbed with red chalk to mark that part of the surface which is
not at right angles to the hole, and the circular edge of the boss serves for the guidance of the file in
finishing the exterior margin: visually rather than obstructively, as the wooden hoss would be reduced
instead of the file being checked. If therefore many such objects had to be filed, two bosses or tem-
plets would be made of hardened steel, and used one at each extremity of the hole, and they would be
held in position by grasping the three pieces collectively in the tail-vice. The same general method is
very largely and more rigorously followed in making joints or hinges.
The brass and steel plates, Fig. 1692. used for the joints of carpenters' rules are filed up to templets
in all respects after the manner described in reference to the snail-wheel, Fig. 1689, and the joint-plates
are inlaid by means of the file, saw, chisel, and plane.
The joints of dr.wing-compasses are made somewhat differently, and mostly as follows: The solid
knuckle, a, Fig. 1693. is first drilled and made circular by aid of a templet c. and the hollow side b is
filed to correspond exactly with a; the two are then pinched together in the vice on the line dd, and
the parallel notches for the steel joint-plates are made in each with the saw, as deep as the line c.
The parts a and b are then separated. the notches in b are completed with the frame-saw, and the bot-
tom of the notches in a are rendered circular with the joint-saw. The middle plates, when filed a little
larger than the templets c. are inserted in b, and soldered in their places; the two parts are smoothed
on their various internal surfaces, and united by a temporary joint-pin. and any little irregularities in
the external or circular curves, (which are left purposely a trifle too large,) are mutually detected by
their want of agreement when the joint is opened to different distances any parts in excess are very
carefully reduced with a small smooth file, principally by draw-filing, after which the screw-pin with
its brass cheeks or bosses is added.
The pin-drill is commonly used for cutting out the concave parts that extend to the side of small
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compass-jointa, such as are represented in Fig. 1694, and also for inlaying the heads of small counter-
sunk screws.
Larger joints with wider knuckles, such as Fig. 1695, are in many instances cast from patterns closely
resembling the finished works. In such cases the first process is generally to remove any little exter-
nal errors with the file, and to clear the angles with a small chipping chisel; the faces of the knuckles
are then smoothed and inserted within one another very tightly. The joint-hole is afterwards drilled
throughout all the knuckles, and which are filed up externally, sometimes under the guidance of tem-
plets put at the ends, but principally by the reduction of those high parts which get scratched or rubbed
by the opposite parts, and thereby show their excess of height.
a
1692.
1693.
z
1694.
b
b
But if such joints are required to be made more accurately, the holes are first drilled in each piece
separately, and rather too close in the corners; the holes are broached with a parallel broach, 80 as ex-
actly to admit a steel cylinder, Fig. 1696, which has a square end for the brace; this rod is intended to
receive the cutters, shown on a larger scale in Fig. 1697, which are cylindrical pieces of steel bored to
fit the rod, and cut with teeth on the outer cylindrical part and on one flat surface; R pin is inserted
through both the cutter and bar, 80 that the two may be united after they have been placed within the
joint to be worked; sometimes the back face of the cutter has only a diametrical notch to receive the
driving-pin, which pushes the cutter before it as it revolves. A recess must first be cleared for the cut-
ter with a chisel and hammer, or by a wide-joint saw or cutter; and the hollowed parts at aa, Fig. 1695,
are then cut throughout their length with the cutter, that afterwards serves to flatten the faces of the
knuckles in exact parallelism throughout, and at right angles to the central hole.
a
1697.
1695.
1696.
The two halves of the joint, having been separately hollowed, and faced until the knuckles will pene-
trate some distance into one another, the external parts of the joint are next separately filed under the
guidance of hard steel rings, or templets, of the same diameter as the cutter, and placed on the cylin-
drical rod; after which. the two parts of the joint are put together when yet slightly too large, and the
central pin is inserted, in order that the rubbing of the knuckles against the corresponding hollows may
denote the parts that are still too high or full; and by cautiously removing all the parts that are
abraded, the joints may be made to fit very closely and accurately, and yet to move with great smooth-
ness.
Many joints that are at the same time wide and small, as in hinged snuff-boxes, could not be drilled,
as above described, with safety, and are therefore made quite differently, by means of small tube, called
joint-wire.
For instance, in making a snuff-box, the rims for the top and bottom are fitted and jointed together
before the top and bottom plates are soldered in, and the joint is thus constructed. Supposing that five
knuckles are required for the bottom, and four for the top, the nine pieces of joint-wire are cut off, and
filed square at the ends; the rims for the top and bottom having been fitted 80 as to form the rebate,
are placed together, and carefully filed out with a semicircular recess, or groove, by means of a parallel
round file, or a joint-file, exactly of the diameter of the joint-wire, which therefore leaves a hollow equal
to the fourth part of the circle in each rim.
Five of the joint-pieces are then strung on a wire, inserted in the hollow of the rim for the bottom of
the box, and tied therein with fine binding wire; the intervals between these five knuckles are regu-
lated by inserting the other four between them for the moment, while the binding wire is being fast
ened; after " hich this first serios of knu kles is solder d in with mod erately hard ilver solder, which
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FILTRATION.
is usually fused with the blow-pipe. The lid is then treated in the same manner, and the bottom part
of the box now serves as the gage for regulating the distance between the knuckles in the top rim.
The same plan is also used by mathematical instrument makers and others, who however more gene-
rally turn the joint-pieces in the lathe, as the draw-bench forms no part of their ordinary supply of tools;
and the wide joint-pieces or knuckles in mathematical works are usually larger than could be produced
in that manner.
FILTRATION. The process of separating liquids from the substances mechanically suspended in
them, by passing them through some porous material, sufficiently compact to retain the insoluble
matters.
The materials employed as filters are numerous; as, porous stone, broken stone, glass or earthen-
ware, gravel, sand, sawdust, pulverized charcoal, chaff, straw, sponge, paper, cotton and linen, and
woollen cloth. These and many other things are made use of in the arts, but some of them have a
particular application as being better suited to the character of the liquid to be strained, and the perfec-
tion required in the process. Thus, unsised or filtering paper is generally used for chemical purposes;
charcoal for oi!s and sirups. Care should be taken in the selection of the material that no injurious
chemical action ensue, 80 that the liquid, in passing through, may not lose any essential quality nor
acquire any deleterious one.
Under the heads, sugar, oil, &c., will be found a description of the filters used in their manufac-
ture; we shall confine ourselves now to the filters used for the puritication of water for the supply of
cities and towns, and for domestic purposes. In all filters the rapidity with which the liquid passes
through the filtering materials, or the quantity of strained liquid discharged in a given time, depends
on the porosity of the filtering materials, the extent of their surface, the fluidity of the liquid itself, and
the pressure under which it is forced through.
Among the first plans adopted for filtering on a large scale was by drawing the water into
trenches, excavated below the level, beside, and a few feet distant from the stream which was to afford
the supply; the intervening earth forming a natural filter. This arrangement has been found to answer
well in some cases where the trenches excavated were extensive in comparison with the supply
but where from the demand, the level of the water in the trench is drawn unsiderably below that of
the stream, so that the water passes through under pressure of some amount, the rapidity of the
percolation of the water is found to diminish rapidly, from the drawing off of the finer earths into the
body of the filter, filling up the interstices. New trenches have now to be excavated, in addition, and
this is but a temporary relief, and, to prevent the filling up of the trenches, they have to be walled
up and covered; on the whole, this plan of filtering was found to be expensive, especially when a large
supply was needed.
At the Chelsea Water Works, London, two subsiding reservoirs are used, 80 that the water in one of
them can always be in repose, 80 as to deposit the heavier matters in suspension; a precaution al-
ways, if possible, to be adopted After the deposition, the water passes through a filter of gravel and
sand in a third reservoir. From time to time the top layer of sand is stirred up and renewed. and in
course of time the whole material of the filter. This is of course expensive, and some readier and
cheaper way of cleansing the filtering material has been sought. This has been effected by changing
the direction of the current of water; that is, if the water has been passing down through the filter, to
make it pass up, or vice versa: by this means the material is cleansed and continues to serve the pur-
pose of filtering without replacing or change, and on this principle most filters are at present constructed.
No large filtering apparatus is attached to the Croton Water Works, but for domestic purposes the
diaphragm filter of W. M. Gibson, of New York, has been found to answer an excellent purpose, and is
in extensive use throughout the United States. It consists of a metal box, Fig. 1698, shaped like a dish
or flattened spheroid, about five inches in diameter, and not larger than a pint
1098.
measure, with a screw-fitted orifice in the centre, on both sides, either oritice
of which is screwed to the hydrant pipe faucet,and is adapted to any vessel,
1699.
pipe, or reservoir; the filter suffers the water to pass through, but retains the
impurities. The quartz a, Fig. 1699, is enclosed between two diaphragms of fine
silver wire gauze and Britannia metal plates, and the water passes through
both the gauze and the crushed quartz. To clean the filter, unscrew and re-
verse it once a day, and the water will instantly wash away the sediment,
slime, animalculæ, and all other impurities, and then run pure, clear, and pellucid as before. They can
be attached to any hydrant, and under a pressure of eight feet head, will deliver a gallon a minute.
Large filters, on the same principle, are made for manufacturing purposes, which can render 200 to
400 barrels of turbid water clear in an hour.
The following is the construction of a filter on a more extensive scale: The stone pipe A brings the
water from the regulating basin to the filters, and iron pipes communicate between the stone pipe or
aqueduct and the top and bottom of the filters.
A valve near the top of the iron pipe S P, at S, Fig. 1700, forces the water to enter on the top or at the
bottom of the filter at pleasure. The filter is 100 feet in length, and 60 feet in breadth. divided into three
compartments, which may either act together or separately, 80 that when one compartment is being
cleansed, the other two continue in operation. The site of the filters is a piece of level ground. exca-
vated to the depth of 6 or 8 feet, with retaining walls all round, joined with cement, and puddled be-
hind, 80 as to become water-tight. The bottom is laid about a foot deep with strong stiff puddle, over
which is a pavement 80 cemented as to be impervious to water. The whole of this bottom is then di-
vided into drains or spaces, 1 foot wide, and 5 inches deep, by means of fire-brick laid on edge, and
covered with flat tiles, of the same material, perforated with small holes, like those used in a kiln for
drying oats. These holes are placed very near each other, and are rather more than 1-10th of an inch
in diameter; there is also a space of f of an inch left open between the ends of the bricks, which sup-
port the perforated tiles, and their upper edges are little more than an inch broad, in order that there
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FILTRATION.
647
may be no space without holes, and nothing to prevent the water spreading equally over every part of
the bottom of these drains. This is particularly necessary when the filters are being cleaned by the
upward motion of the water. The perforated tiles or plates are covered to the depth of 1 inch with
clean gravel, about 3-10th of an inch in diameter: this is followed by five other layers of gravel, each
of the same depth, and each succeeding layer a little finer than the previous one, the last being coarse
sand over this is placed 2 feet depth of clean, sharp. fine sand, similar to that used in hour-glasses,
but a very little coarser; about 6 or 8 inches deep of the fine sand nearest the top is mixed with ani-
1700.
s
"
mal charcoal, ground to the size of coarse meal, each particle about 1-16th of an inch in diameter. A
longitudinal drain or pipe N runs between the filter and the pure-water basin. communicating with
both; on each of the openings between the pipe and the filter is a stop-cock to close the communication
when necessary; there are also two drains, to carry off the foul water when the filters are being cleaned,
and another to prevent the water from rising too high: when the filter is complete, its action is as fol-
lows: The aluice R and the valve S are opened, and the water permitted to flow through the filter into
the drain N below, until it becomes quite clear. This will take two or three days when first set to
1701.
L
work, unless very great pains are taken to wash the gravel and sand before they are put into the filter,
which will now flow copiously for some weeks, and when the quantity passing begins to decrease, the
stop-cocks are shut, and the valve SS raised. The water then enters below, filling all the drains, and
having a head pressure of several feet it will force its way up through the sand to the top. and in its
passage raise the scales or particles of mud which have been deposited in the downward passage, and
carry them into the foul-water drain below. If the sand of the surface be stirred by a fine-toothed rake,
1702.
$
$
9
after the water has been raised above it, and a little additional water admitted on the top, through the
conduit, it will facilitate the operation of cleaning, as the mud is always deposited on the very surface
of the sand. By this means the sediment will be carried off, and the water pass through quite clear
again in a few hours: the valves S should then be lowered, the stop-cocks opened, and the operation
of filtering will again proceed as above described. The cost of this filter would be about $3000, and
the quantity of pure water produced regularly every 24 hours on an average about 106,632 cubic feet.
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648
FIRE ANNIHILATOR.
M. Fonvielle, of Paris, has invented a filter in which two currents of water instead of one are em-
ployed to cleanse the materials used for filtering. This arrangement can be readily understood from
the section, Fig. 1703, in which S is the pipe sup-
1703.
plying water to the filter D, the discharge pipe; a a,
a
stop-cocks by which the current may be made to
pass in any direction through the filtering material
F, which is supported between two perforated dia-
phragm plates. When in operation one cock only
in each pipe is opened, diagonally opposite, as
S
D
shown in the section. But to cleanse the filtering
materials, both supply-cocks are opened and one
discharge-cock, alternately the lower and upper; by
this means the filtering materials are effectually
cleansed. Filters on this principle, with numerous
compartments and of various cupacities, are used
for the filtration of the waters of the Seine, and give complete satisfaction.
A floating filtering pump has been patented in England. A flont supports the filter submerged a
few inches, and it is connected by a pipe with a joint or piece of hose to the pump. By these means
the water is drawn always from near the surface of the water, where the least matter is suspended.
Without the filter a floating supply-pipe, whose aperture is always a few inches only below the surface
of the water, would be a useful appendage to many pumps, since water drawn from near the bottom of
a reservoir is very apt to be turbid.
FIRE ANNIHILATOR. A portable machine for domestic use, which is stated to possess the power
of almost instantaneously extinguishing fire.
Fig. 1704 exhibits a section of the annihilator, which is composed of a set of light iron cases, thus
arranged A and B the two outer cases, forming a close water-chamber; C and D two inner cases, per-
forated in such a manner as to allow the free passage of vapor; E the inner lid; F the outer lid, or
cover; G a water-pipe, forming the handle; H the
charge; I the igniter; K the igniting-pin. The
work of charging the machine is performed in a
minute. The two lids F and E being taken off,
the charge (which is already provided with the
1704.
igniter bottle) is introduced, and the two lids are
H
H
replaced, the outer one being secured by a thumb-
screw. The igniter pin is placed in the neck, and
covered with the wooden stopper, and this may
be sealed down at pleasure. Water is then poured
G
into the handle, and confined by a small screw-
plug.
The charge K is a compound of charcoal, nitre,
and gypsum, moulded into the form of a brick.
The igniter I is a glass tube enclosing two bottles
-one containing a few drops of sulphuric acid,
placed over another containing a mixture of chlo-
rate of potassa and sugar.
The mode of using the annibilator is to carry the
machine to the place on fire, take out the wooden
stopper, with the knob of the stopper strike down
the plug or pin in the neck of the machine, and
hold the machine by the handle in the best posi-
D
D
tion for the vapor, which will come out of the hole
on the top to reach the flame, which is almost mo-
C
mentarily extinguished. The action of the ma-
chine is as follows: The pin being forced down,
B
B
breaks the igniter bottle, when the sulphuric acid
falling on the mixture of chlorate of potassa and
sugar, ignition takes place; the flame spreads over
the upper surface of the charge, which instantane-
ously ignites, and evolves heated gases; these, in
their passage through the perforated cylinders,
impinge against the water-chamber, expand the
contained air, and produce steam, by which the
water is forced through the tubular passage. The
steam of the water mixing in the annular chamber with the hot gases, they escape together from the
discharge tube in a dense expansive cloud, and are continuously delivered until the charge and water
are expended.
Mr. Phillips, the inventor, states the portable machine to be applicable to the protection of dwelling-
houses, detached buildings, and ships; but it is requisite that public stores, warehouses, manufactories,
and large pile of building, be protected by stationary engines of immense power, the construction of
which varies materially from that of the portable machine, although based on the same principle of
action; namely, that of extinguishing fire by gases and vapor resulting from combustion.
FIRE-ARMS. See GUNS.
FIRE BOX. See DETAILS OF ENGINES, page 508.
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FIRE ENGINE.
649
FIRE-BRICKS. Used for furnaces and the lining of stoves where great heat is generated, are
moulded in various parts of the United States. At Newark, Amboy, and other places in New Jersey,
where the loam contains a considerable amount of sand, they are made in large quantities. Rondout
(on the river Hudson) and Long Island bricks are a similar quality, and will stand the action of great
heat.
Retorts for a variety of purposes are made with a mixture of clay and iron, particularly for the manu-
facture of gas; the iron retort receiving a casing of prepared clay, which permits the fire to act first on
the clay. and thus prevents the rapid destruction of the metal.
Retorts or bricks made of one part pure clay and three parts of coarse and pure sand, slowly dried
and annealed, will resist a very high temperature, and are not readily fused; but if in contact with any
metals in a fusible state, which are suffered to oxidize, they will then act upon the earthy matter, and
cause it rapidly to fuse.
A long-continued white heat will soften the compound made of any of the silicious and aluminous
earths; therefore clay and sand are not so well adapted to bear a great heat as an entire clay coarsely
powdered and burnt clay being substituted for sand, the vessels which contain glass in the furnace, and
which are subjected to intense heats, are thus made, and resist for a length of time the action of the
saline fluxes they contain.
Windsor loam, or a mixture of clay and sand, made by beating a thin paste, is employed as a lute to
unite the joints of fire-bricks, or to set them in instead of common mortar; and if it is required that
vitrefaction should take place with the clay 80 used, borax or red lead, mixed in small portions, will
produce the effect; such a compound will destroy the porosity of earthenware, when exposed to high
temperatures. See FLOATING BRICKS.
FIRE ENGINE. This most useful machine is constructed in a variety of forms, which all, however,
agree in one principle. It generally consists of a double forcing pump communicating with the same
air vessel; and instead of a force-pipe, a flexible leathern hose is used, through which the water is driven
by the pressure of the condensed air in the air vessel The annexed diagram represents a section of
the apparatus. The pipe T descends into a receiver or vessel containing a supply of
water. This pipe communicates with two suction valves V, which open into the
1705.
pump barrels of two forcing pumps A B, in which solid pistons P are placed. The
piston-rods of these are connected with a working beam F, elongated, so that a num-
ber of persons may work at both ends of it at once. Force-pipes tt proceed from the
sides of the pump barrel above the valves V, and they communicate with an air
vessel M. by means of forcing valves V, which also open upwards. The pipe
descends into the air vessel near the bottom. This pipe is connected with the flexible
leathern hose L, the length of which is adapted to the purposes to which the machine
is to be applied. The extremity of the hose may be carried in any direction, and
B
may be introduced through the doors and windows of buildings. By the alternate
action of the pistons, water is drawn through the suction valve, and propelled through
the forcing valves until the air in the top of the vessel M is highly compressed. The
pressure acts on the surface of the water in the vessel, and forces it through the leathern hose in a con-
tinued stream, so as to spout from its extremity with a force depending partly on the degree of conden-
sation, and partly on the elevation of the extremity of the hose above the level of the engine. It is to
be considered that the pressure of the condensed air has, in the first instance, to support a column of
water, the height of which is equal to the level of the end of the tube above the level of the water in
the air vessel; and until the pressure exceeds what is necessary for this purpose, no water can spout
from the end of the hose; and, consequently, the force with which it will so spout will be proportional
, the excess of the pressure of the condensed air above the weight of the column of water, the
weight of which is equal to the elevation of the end of the hose above the level of the water in the air
vessel.
The fire engine has received various improvements from 1518 to the present time. The above
description applies to our ordinary engines, Fig. 1706.
Braithwaite's steam fire-engine is an application of the power of steam to the working of the fire
engine. The mechanical arrangement consists of two cylinders of about six inches in diameter, one of
them being the steam cylinder, and the other the water pump; and they are placed horizontally, 80 that
a parallel motion is easily produced. This engine will deliver 9000 gallous of water an hour at the
height of 90 feet. The time of getting the machine into action, from the time of igniting the fuel, (the
water being cold.) is only 18 minutes. Some of the fire insurance companies in London have floating
engines on the Thames, which are extremely serviceable in cases of fire among the shipping or buildings
near the river.
Of all the engines hitherto constructed and worked by manual labor, the floating fire engine is the
most powerful. Engines of this kind generally consist of three cylinders, working into an air vessel of
large dimensions, and are built in appropriate barges. They are put in motion by the power of from
forty to fifty men, applied to four long revolving cranks, which, by suitable machinery, work the three
pistons. These engines will throw a column of water, one inch in diameter, upwards of a hundred feet
high. They are advantageously employed on the river and in docks, where an abundant supply of
water can always be depended upon.
These engines, however, have been greatly surpassed by the fire engine recently constructed, worked
by steam power. The engine of this kind, built for the Prussian government in 1832, had two working
cylinders ten inches and a half in diameter, with a fourteen-inch stroke, the steam cylinders being
twelve inches in diameter. When working with a steam pressure of seventy pounds upon the square
inch, and making eighteen strokes per minute, this engine threw a jet of water, an inch and a quarter
in diameter, nearly one hundred and twenty feet high. The same power gave two jets of seven-eighths
of an ir ch, and a terwards four or five-ei ghth of an irch, an elevation of about eighty feet The ccp-
82
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650
FLASH BOARDS.
sumption of coke was three bush-
els per hour, and the average
working of the engine was calcu-
Inted to be equal to the discharge
of between 80 and 90 tons per hour.
Steam fire engines have been
tried in this country, but have not
been found to be sufficiently eco-
nomical to warrant their use. A
common and convenient form of
fire engine is shown, Fig. 1706,
taken from one of the smaller
New York engines. The cylinder
shown on top of the carriage con-
tains a reel, on which is wound a
supply of hose. It is usually pro-
tected by a cover of patent-leather,
tastily ornamented. A suction-
hose is swung on the side of the
engine. Generally the hose is
carried on a separate carriage, and
when the supply of water is to be
taken from an aqueduct the suc-
tion-hose is unnecessary. In this
engine it will be perceived that
the power is applied by brakes,
1706.
and that the movement is up and
down. To increase the power of
such engines, in some places, a
rope is att ched to each of the
brakes, which passing over blocks
or sheaves fastened to the bottom
of the carriage, are grasped by
rows of men at right angles to the
body of the engine, who, by recip-
rocating pulls, assist very much
the men at the brakes.
Besides the up and down brakes
there are engines in much use in
Cincinnati and at the West, in
which the movement is horizontal;
the men sit at their work, and the
action is similar to that of rowing.
Various engines on the rotary
principle have been constructed.
The power was generally applied
by means of a crank. but they
were found very laborious in their
operation, and liable to disarrange-
ment. They are now seldom used
as fire engines in the common ac-
ceptation of the term; but as sta-
tionary force-pumps, driven by
steam or water, there are some
which are extremely valuable and
useful. See PUMP.
FLASH BOARDS. Movable boards placed on the top of a dam or weir, to retain the water of the
b
b
b
1707,
1708.
e
c
d
CL
a
e
stream when the flow is small which, in case of floods, are removed to give free vent to the surplus.
In case of low water, therefore, they maintain the head, and in case of freshets, there is less obstruction
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
651
and less danger from flowage than if the structure was permanent to the level of the top of the flash
boards. On the dams of the rivers which, when swollen, bring down ice or flood-wood, flash boards are
used, of rough boards supported by iron rods inserted in the top of the dam, the joints being stopped with
saw-dust, shavings, or gravel; and as the water rises the irons are bent down, and the boards are swept
off by the flood. Where there is no danger from ice or floating lumber, or very sudden rising of the
water, flash boards a are constructed 80 as to be removed by hand, Figs. 1708 and 1707, about 4 feet
long, and from 6 inches to 12 inches wide, with long handles b at each end, at right angles to the board,
by which a person standing on the platform c can raise the boards. They rest in the rabbits of posts
or stanchions d, and are placed one above another to the required height. Flash boards of this form
being easily managed, are almost invariably used on the waste-weirs of canals, to regulate the height
or level of the water.
FLASHING. The accumulating of a flow of water, by movable constructions, for the purposes of
manufacturing, navigation, or scouring. See SLUICES and SEWERS.
FLASK. The iron or wooden frame or box which serve- in foundries to support and contain the sand
used in moulding. See CASTING, Figs. 807 to 836.
FLAX, Machinery for preparing and spinning. Flax, compared with the other materials used in
the textile manufactures, such as wool and cotton, possesses several characteristic properties. While
the latter are presented by nature in the form of insulated fibres, which simply require to be freed from
their impurities previously to being spun, the former must have its filaments separated from each other
by tedious and careful treatment. This circumstance has opposed 80 serious an obstacle to the success-
ful introduction of machinery, as materially to have retarded the progress of the linen manufacture;
and it is only within the last thirty years that the distaff and the hand-wheel have been entirely laid
aside. Such rapid progress has, however, been made during that period in the improvement of flax
machinery, that it has now attained to a state of perfection little short of that by which the cotton
manufacture has been 80 long distinguished.
The double breaking machine.-The flax, when delivered at the mill, (having previously undergone
such preparation as entirely to free it from its boon or woody particles, and to dissever its grosser
filaments,) consists of long parallel fibres of different degrees of fineness, and varying from 26 to 36
inches in length. After having been duly assorted, it is divided into stricks, or small bundles, which
are brought to this machine for the purpose of being cut or broken into two, three, or more lengths,
according to the nature of the flax, the length of the staple, and the different sorts of yarn into which
it is destined to be spun. It is most generally divided into three lengths, in which case the finest and
best qualities of yarn are spun from the middle portion, on account of the superior strength as well as
delicacy of the fibres at that part.
Fig. 1709 is a front elevation, and Fig. 1710 an end view of the breaking machine.
LL, the iron framework of the machine.
MM. the fast and loose pulleys.
NN, the cutter or breaker, fast upon the driving shaft. It is constructed of three wrought-iron rings,
firmly bolted together between two cast-iron flanges these rings have projecting points formed at
regular intervals on their peripheries, and 80 disposed, when in combination, as to present numerous
diagonal groups of cutters all round the circumference of the breaker. The cutters are of an elliptical
form, and project about a quarter of an inch.
00, a pair of grooved wheels fixed upon a horizontal shaft at a short distance on each side of the
breaker, which revolves between them.
P P, a similar pair of wheels with projections on their circumferences, fitting into the grooves in the
wheels 00, and revolving in the contrary direction.
QQ, a set of compound levers, rods, and weights, for keeping the upper grooved wheels PP in con-
tact with the lower 00. The purpose of these wheels is to bring the strick of flax under the action of
the breaker, while the levers and weights QQ maintain the requisite pressure upon it; the shaft car-
rying the upper grooved wheels being capable of moving vertically in the framing LL
The opposite end of the machine is provided with a set of grooved wheels, weights, and levers, in
all respects the saine as those shown in Fig. 1709.
R R, a pair of spur-wheels fast upon the shafts of the upper grooved wheels and working into
SS, a similar pair of spur-wheels fixed to the shafts of the lower grooved wheels 00, which is
driven by a train of wheels at the opposite side of the machine. The wheels R RSS are made with
teeth of a somewhat greater length than usual, to allow the flax to pass between the grooved wheels
without disengaging the connection.
TTT, a train of spur-wheels and pinions by which the motion of the driving shaft is communicated,
with a greatly reduced velocity, to the grooved wheels
Action of the machine.-The strick or small bundle of flax is held in both hands, and laid trans-
versely against the grooved wheels OOPP, which rotate slowly in the direction of the breaker. The
latter, which makes about 300 revolutions per minute, tears or breaks it across by separating but
not cutting the fibres. Two hands may be employed at the same time at this machine, one at each
side.
The coarser having been thus divided from the finer portions of the flax, each sort is collected into
a separate heap, and it is then ready to undergo the next process; namely, the hackling.
Hackling, and hackling machinery.-This is an operation of the utmost importance in the prepara-
tion of flax, as its successful accomplishment affects not only the quality but the quantity or yield of
&
the yarn into which it is ultimately converted. The object proposed by it is threefold First, the part-
ing of the filaments into their finest fibrils; secondly, the separation and removal, with the least possi-
ble injury to the real fibres, of the tow, or short fibres which adhere to the former and bind them
together ; and thirdly, the equable and parallel arrangement of the long filaments. To accomplish
these objects, the flax is drawn successively over two or more surfaces, thickly studded with sharp steel
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
653
pins, or hackle teeth ; the thickness of these, and their degree of approximation varying with the pro-
gressive stages of the operation.
In hackling by the hand, the operative wraps one end of the strick of flax firmly over his right hand,
throws it upon the points of the coarse hackle, and draws it towards him, while he holds the left hand
upon the other side of the hackle, in order to spread the flax, and to prevent it from sinking too
deeply among the teeth. The other end of the strick is treated in the same manner; and the opera-
tion is repeated, first upon the coarse and then upon the fine hackles, until the fibres have been
reduced to a sufficient degree of fineness, and, by careful handling, little more tow can be formed. To
facilitate subsequent operations, the ends of the strick of flax should assume, at this stage of the pro-
ceis, an elliptical form when laid on a flat board. For this purpose the hackler wraps the end of the
dressed strick round a pin shaped like a knife, and breaks or pulls away such of the fibres as by their
length would tend to give it a pointed instead of an elliptical shape.
The hackling machine consists of two horizontal cylinders about 3 feet in diameter, on the peripheries of
which are fixed hackles; the strength and number of these being varied according to the different
stages of the operation. These cylinders are fixed upon shafts which are made to revolve with a con-
aiderable velocity in directions contrary to each other, both cylinders moving towards the centre of the
machine. At each end of these cylinders is placed a large spur-wheel, geering with a central one,
called the transfer wheel, situated between the two hackle-cylinders. All these wheels are fitted with
a number of segments fixed to their inner surfaces and forming a species of drums, of a diameter
considerably greater than that of the hackle-cylinders. Each of these drums contains a series of re-
cesses, into which are fitted the clamps or strick-holders by which the flax is secured. The drums and
hackle-cylinders are set with a considerable degree of eccentricity in relation to each other, 80 that
the rim of the external drum may be further from the hackles at the back part of the machine, where
the operation commences, than at the part where the strick is delivered to the transferring mechanism;
this arrangement is requisite for the purpose of subjecting the end of the strick to the action of the
hackles for a longer period than the middle, where the fibres are naturally much stronger, finer, and do
not contain so much tow. The operation of this machine is as follows: the stricks having been firmly
secured to their holders, the latter are inserted into the recesses of the first external drums; these
rotate with a slow motion towards the centre of the machine, and the hackle-cylinders, revolving
within them in the same direction but with a much greater velocity, dress the under sides of the
stricks. On reaching the transfer wheels the strick holders are, by an ingenious combination of slides
and weighted levers, disengaged from the back cylinder, and pushed into the recesses on the transfer
wheels; by these they are inverted and conveyed to the front cylinder and drums, which complete the
process by hackling the upper side of the flax.
On being delivered at the front of the machine, which we have supposed to be the first, or roughing
hackle, the stricks are conveyed by the attendant to the finishing machine, which is in all respects
identical with that described, but is furnished with finer hackles. After passing through this the
strick holders are unscrewed, and the undressed ends drawn through them; they are again secured and
returned to the roughing machine, where, by a repetition of the process already described, the opposite
ends are finished. For further particulars of the hatchel, see rope manufacture.
The tow is cleared from the hackle-cylinders by means of revolving brush-cylinders situated at each
end of the machine and underneath the centres of the former. From the brush-cylinders it is again
transferred by doffing cylinders covered with card filleting; these latter are cleared by means of doffing
knives, worked by eccentrics on the end of the brush-cylinders, the tow being delivered in broad sheets
on the floor of the factory or into proper receptacles. The carding and spinning of the tow is per-
formed by machinery similar to that employed in the cotton manufacture, though of considerably
greater strength.
The spreading machine.-The next process undergone by the flax is its conversion into an endless
band of parallel and rectilinear filaments, called a sliver, being the foundation of the future yarn.
This is accomplished by the machine now under notice, which is fully delineated in Figs. 1711 to
1716.
Fig. 1711 is a front elevation of the spreading machine; Fig. 1712 a side elevation; Fig. 1718 a
general plan; and Figs. 1714 to 1716 detached views, on an enlarged scale, of the spirals and fallers.
AA A, the cast-iron framework of the machine.
B B, the driving shaft, fitted with a fast and loose pulley.
CC, the feeding or spreading table; it is divided into two compartments, the one being considerably
longer than the other, for the convenience of the attendants who spread the flax.
DDD. rollers situated at each end of the feeding-table over these pass four endless leather straps,
upon which the stricks of flax are spread.
E E, a polished iron plate, upon which are fixed the guides which serve to conduct the flax to the
back or detaining rollers.
F, a cylindrical tin can, placed in front of the machine to receive the sliver.
aaa, the front or lower drawing ruller.
bbb, the top drawing or pressing rollers, made either of wood or iron, and covered with leather.
ecc, the back or detaining rollers.
G G. two weighted levers for imparting the requisite pressure to the top drawing rollers.
HH. two weighted levers bearing in a similar manner upon the top detaining roller.
dd, the fallers or gill bars, forming a sheet of advancing hackles between the detaining an I drawing
rollers; these are for the purpose of producing great regularity in the draught, and a perfectly parallel
distribution of the fibres.
ece, the rubbers for clearing the top drawing rollers from adhering fibres.
fff. brans guides for conducting the sliver to the drawing rollers.
gg, the sliver-plate, formed with bevelled openings for the aliver to pass through towards
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FLAX. MACHINERY FOR PREPARING AND SPINNING.
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
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hh, the calender rollers, by which the four slivers compressed into one, and delivered in the
form of a riband into the can F.
K, the calender rolling shaft.
ii, cast-iron hangers for transmitting the pressure of the weighted lever G to the top drawing
rollers.
k k, are similar hangers attached to the lever H.
11, the spirals or screws; into the spaces between the threads of which the ends of the fallers are
inserted.
m, two pairs of small bevel-wheels by which the lower spirals are driven from the back shaft.
two small spur-wheels communicating motion from the lower to the upper spirals.
00, the tappets or cams by which the fallers are elevated in succession from the lower to the upper
spirals, and vice versa.
P p, small weighted levers for guiding the fallers between the threads of the spirals.
q. a small endless screw cut upon the extremity of the axis of the lawer drawing rollers aa; it
works into
r, a worm-wheel on the axis of which is another endless screw, driving a similar wheel, called the
bell-wheel; at every revolution of this last wheel, a pin fixed into its rim acts upon a spring L, to the
end of which a bell is attached. Thus the ringing of this bell serves to register the length of the
aliver delivered into the can.
The following is the detail of the wheel work in this machine:-On the driving shaft B is fixed the
spur pinion s, working into the wheel t on the lower drawing roller shaft; to this latter axis is affixed
the wheel u, whose motion is communicated by the movable intermediates v and w to the change
pinion x on the back shaft the relative diameters of these wheels regulating the amount of draught or
the degree of extension which the flax sustains in passing between the detaining and drawing rollers.
The opposite end of the back shaft carries the pinion y working into the stud-wheel y'. having on its
boss the pinion 2, which, by means of a movable intermediate z', drives the wheel 1 on the axis of
the detaining roller. This train of wheel work is calculated to produce a nearly uniform surface speed
of the rollers and the sheet of hackles.
A slow motion is communicated to the sheet roller D, over which the feeding bands pass, by means
of the spur-wheel 3 working through an intermediate 2 into the pinion 2.
A uniform velocity is imparted to the lower drawing and calender rolling shafts a and K, by a pinion
4 on the extremity of the former, working through an intermediate wheel 5 into a similar pinion 6 on
the end of the latter.
And lastly, a revolving brush situated under the lower range of fallers, for the purpose of clearing
away the dust, is driven by the stud-wheel 7, geering with the pinion 4, and having on its boss a small
pinion working into the wheel 8 on the end of the brush-shaft.
Action of the machine.-The flax is placed in the sheet-iron guides behind the detaining rollers and
along the endless bands or feed sheets, by laying down one handful after another, 80 that the points of
the second strick reach to about the middle of the first, and thus preserve a uniformity of thickness in
the feeding. By the motion of the machine it is introduced between the back rollers cc, and carried
forward by the sheet of hackles dd. towards the front or drawing rollers a a b b, which, revolving at a
velocity considerably greater than the former, lengthen or draw it out to a proportional extent; the
hackles at the same time combing, separating. and straightening the fibres. The slivers from the four
drawing rollers are then passed through the bevel slits in the sliver-plate g g, and united into one by
the calender rollers h, where they are subjected to a gentle pressure and delivered into the can F.
This union of the slivers is necessary in order that the varying thicknesses of each may be compensated
and perfect uniformity attained. When the can has received its destined supply, the ringing of the bell
warns the attendant to break the flax, remove the can, and substitute another.
The drawing frame.-The next process in the preparation of flax consists in causing it to pass twice
in succession through the drawing machine, for the purpose of still further increasing the fineness and
uniformity of the sliver.
These machines, which are represented in Figs. 1717, 1718, and 1719, are in principle identical with,
and in the details of their construction, very similar to, the spreading machine already described. They
contain, as will be seen by the drawings, two sets of fallers and rollers, and the place of the feeding
table and guiles is supplied by a bent plate of polished sheet-iron C, extending across the entire breadth
of the machine, over which the slivers glide in passing from the cans to the detaining rollers. These
latter differ slightly from those used for the same purpose in the spreading machine; here they
are three in number, and coupled together by small pinions, 1, 2, and 3, and disposed in a triangular
form, the sliver being made to pass under the first, over the second, and under the third. With these
exceptions there is no essential difference between the present machine and that last described, and as
we have been careful to designate the same or analogous parts in both by the same letters, it will be
unnecessary to repeat the description.
Spiral or screw gill.-Figs. 1720. 1721, and 1722 give a representation of a very interesting and im-
portant piece of mechanism which enters largely into the construction of modern flax machinery. This
ingenious contrivance has, in a great measure, superseded all former modes of effecting the same object,
which is the combing and separating the fibres of the flax, in order to facilitate the drawing and to give
uniformity to the sliver.
The fallers or hackle bars dd, Fig. 1721, are supported at both extremities by the horizontal steel
guide rails k k, screwed to the insides of the sockets in which the spirals or screws work these
sockets being bored in projecting parts cast upon the stands DD. The lower screw is driven from the
back shaft by a bevel-wheel and pinion m m', and a small spur-wheel n, on the back of the bevel pinion,
works into a corresponding wheel on the top screw, driving both screws at equal velocities but in
contrary directions. In the sides of the sockets in which the screws revolve, openings are formed,
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
parallel with their axis and coinciding with the surfaces of the guide rails k k; through these openings
the ends of the gill-bars, (which are steeled and bevelled to compensate for the angle of the threads,)
are inserted into the helical grooves of the screws. Thus the rotary motions given to the spirals cause
the fallers to be driven along the guide rails in a vertical position, and with a uniform simultaneous
movement; the top sheet in the direction of the drawing rollers, and the lower towards the detaining
rollers.
On reaching the front part of the machine, close behind the drawing rollers, the fallers are depressed
and put out of operation by means of the rotary cams 00, fixed to the ends of the top screws; being
guided vertically downwards between the ends of the upper guide rails and the weighted levers P.
They are thus engaged in the threads of the lower screws, which carry them to the opposite end, where
similar cams 00, and weighted levers pp, raise them successively into their original position on the
upper guide rail, where they are traversed forward as at first. It is usual to make the lower spiral
with the threads considerably wider than those of the upper, which arrangement diminishes the total
number of fallers requi-ite for the due performance of the work.
Self-regulating spiral roving machine.-Fig. 1723 presents a general elevation of the entire machine
as seen in front; one of the plates which protect the spiral pinions being removed in order to show the
mode of giving motion to the spindles, flyers, and bobbins.
Fig. 1724. A corresponding general elevation of the back part of the roving frame exhibiting the
cone and differential movements, and by the removal of one of the covering plates, exposing a part of
the back shaft and geering for working the fallers.
Fig. 1725 is an end elevation, showing the principal geering employed in this machine.
Fig. 1727 is an elevation, partially sectioned, of portion of the spindle rail or beam, and Fig. 1728 is a
plan corresponding.
Fig. 1729 is an elevation, also partially sectioned, of part of the bobbin lifter with its attached geering,
and Fig. 1730 is a plan of the same.
Fig. 1726 is a transverse section of the machine, exhibiting some of its internal arrangements, and
showing the course of the sliver from the cans to the bobbins.
Fig. 1731 is an elevation of part of one of the stands, showing the slides, springs, and weighted levers
used for defining the course of the fallers.
Fig. 1732. An elevation and plan of the contrivance for transmitting motion to the axis of the spirals
on the bobbin rail.
Fig. 1733. A cross section of a part of the machine, showing the apparatus for maintaining constant
tension upon the strap driving the cone pulley of the traverse and equational bobbin motions.
A A, the driving shaft, situated towards the back of the machine and extending throughout its entire
length.
BB, a shaft parallel and near to the driving shaft, extending from the centre to one end of the
machine. It carries a spur-wheel at each extremity, one of which is commanded by the equational
bobbin motion, while the other, by means of A peculiar arrangement of geering, to be hereafter described,
transmits the motion to the spiral shaft on the bobbin rail.
C C, the mangle pinion shaft worked by a train of bevel-wheels from the cone shaft, and, through the
mangle wheel, situated at one end of the machine, close to the driving pulleys, working.
D, the mangle wheel shaft extending the whole length of the machine, and carrying pinions working
into racks 8, 8, 8, attached to vertical slides; these slides are furnished with projecting arms fixed to the
bobbin rail. which is traversed up and down by the mangle wheel; causing the flyers to wind the roving
between the flanges of the bobbins, with all the regularity of a screw. Counter-balance weights 1, 1, 1.
attached to the bobbin lifter by means of chains passing over pulleys, serve to relieve the racks from all
unnecessary strain.
E, a short shaft situated at the back of the machine, and driven by a train of spur-wheels from the
driving shaft at the same velocity as the latter. Upon this shaft is suspended a species of frame, fitted
to slide longitudinally upon it, and carrying two pulleys and a weight at the extremity the first pulley
being adapted to rotate with the shaft E, by means of a long slot and sunk feather, and the other being
merely a conical friction roller, for the purpose of maintaining a constant tension upon the strap driving
the cone F, Fig. 1733. The frame, with its appendages, is traversed along the shaft by means of a
weight 2, situated at the opposite end of the machine, and attached by a chain and adjustable rod to
the frame and to a rack working in a slide fixed to the back of the roller beam, Fig. 1726. This rack is
serrated on both edges, the teeth of the upper alternating with those on the lower edge, and the pawls
are alternately disengaged at every revolution of the mangle wheel in such a manner as to allow the
drag weight to advance the rack and pulley frame by half the distance between two contiguous teeth.
The mechanism by which the pawls are disengaged is as follows :-At the back of the rack slide a short
rectangular bar is fitted to slide vertically, having two projecting pins acting upon the points of the clicks,
Fig. 1726. This bar is worked by the end of a lever inserted through its lower extremity, and having
its fulcrum under the roller beam: to the other end is attached the vertical rod 5, carrying two adjusta
ble catches 4, 4, which, at every alternate movement of the mangle wheel, are struck by an arm 6
extending from the rack 7. Thus one of the pawls is constantly in geer to prevent the rack and
attached pulley frame from being drawn beyond the prescribed limits for each stroke. The lower pawl
is kept pressed against the rack by a counter-weight 3, while the upper one merely rests on it by its
own gravity. The pitch of the teeth on the rack must be varied according to the degree of fineness of
the roving.
F, the cone driven by a strap belt from the pulley on the shaft E, and communicating a gradually
retarded motion, at once to the bobbins themselves and to the traverse of the bobbia rail; the velocity
of the spindles and flyers remaining constant. This is necessary in order to compensate for the con-
tinually increasing diameter of the bobbins as the roving is wound upon them. The come is set at a
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
slight inclination, in order to allow the belt to act upon a greater part of its periphery towards the apex
than towards the base where, on account of the increased diameter, this precaution is less necessary to
ensure the rotation of its shaft. A lever handle (seen in the end elevation, Fig. 1725,) is attached to the
carriage of the cone shaft, for the purpose of raising its outer extremity previously to winding back the
pulley frame.
G H, two short shafts situated towards the centre of the machine, and carrying geering to be here-
after specified, for transmitting the motion of the cone shaft F to the traverse and equational bobbin
motions respectively.
I, a hollow boss fitted to rotate
1733.
upon the driving shaft A, with a mo-
1732.
tion independent of that of the latter,
and carrying at one end a spur pin-
ion working into a wheel on the shaft
N
B, and at the other a bevel-wheel,
being part of the equational bobbin
motion.
1731.
K is a similar bevel-wheel fast
upon the driving shaft A.
LL, the back shaft traversing the
entire length of the machine, and
F
N
carrying the bevel-wheels for work-
B
ing the mechanism of the fallers.
M M, a longitudinal shaft working
in bearings on the spindle rail, and
X
8
carrying the spiral pinions for con-
E
veying motion to the spindles and
flyers, Figs. 1726, 1727, and 1728.
The spindles are disposed in two
rows, so that each spindle in the
back range stands opposite to the
interval between two in the front
%
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range. The object of this distribu-
tion is economy of space, as the ma-
chines would require to be greatly
M
longer if the spindles stood all in one
line. The shaft M is situated be-
tween the two rows, and drives both
rows in the same direction.
NN, a longitudinal shaft working
in bearings on the bobbin rail, and
carrying the spiral pinions for work-
ing the bobbins, Figs. 1726, 1729,
and 1730. The spindles pass through
1728.
brass sockets fixed to the bobbin rail
to hold them steady as the latter
0
traverses up and down. These sock-
M
M
ets serve also as pivots for the spiral
pinions to revolve upon it being
understood that the motion of the
U
bobbin spirals is totally independent
of that of the spindles. A small
flange on the top of each spiral car-
1729.
ries two projecting pins fitting into
corresponding holes in the bottom of
N
the bobbins, and causing both to re-
volve together.
OP, the back detaining rollers
having the iron pressing rollers be-
tween them, which are cut into short
lengths, and are carried round by the
h
1730.
friction caused by their own gravity.
QQ, the axes of the pressing or top
drawing rollers marked 10, which
are usually made of wood, and are
N
pressed against the lower drawing
rollers 12, 12, by hangers 11, 11, rest-
ing in necks cut in the axes and at-
tached to weighted levers 9, 9, pass-
ing under the roller-beam.
RR, a slender rod extending the entire length of the machine, for conducting the slivers to the
detaining rollers. They pass under this rod. and slide over a polished sheet-iron plate covering the back
shaft and bevel geering for driving the gill screws.
SS, a rod by which the attendant is enabled at any part of the machine to stop or set it motion
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1724.
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
TT, are a set of friction pulleys placed upon a rod surmounting the machine, for the purpose of guid-
ing the slivers as they are drawn out of the cans by the action of the machine.
UV, the fast and loose pulleys on the end of the driving shaft for starting and stopping the machine.
W W W, is a train of spur-wheels conveying the motion of the driving shaft A to
X, a spur-pinion on the end of the shaft M, which drives the spindles and flyers with a uniform motion.
YZ, the draught geering between the drawing and detaining rollers, the particulars of which will be
given below.
abcc and d, are spur and bevel wheels and pinions, the combination of which forms the differential
motion for driving the bobbins.
Supposing that the large spur-wheel a, which, through the pinion b, receives its motion from the
cone, were driven at the same velocity as the driving shaft A, then it is obvious that no motion what-
ever would be imparted to the bobbins. On the other hand, if the wheel a were held absolutely im-
movable, the bevel K, which is fixed upon the driving shaft, would convey, through the pinions c, a
motion equal to its own, though in the contrary direction, to the boss I and attached geering; conse-
quently, in the case we have last supposed, the motion communicated to the bobbins would be uniform.
Hence, by combining the two extreme cases, and supposing the wheel a to be driven in the direction of
the driving shaft, but with a slower velocity, it will be understood that the boss I will be made to re-
volve at a speed which, if added to that of the wheel on will be exactly equal to that of the driving
shaft A.
Thus, when the driving strap is at the apex or starting point of the cone F, the wheel a is at its maxi-
mum velocity, and the boss I with the train of wheels to the bobbins at their minimum, causing the
flyers, which revolve at a considerably greater uniform speed, to coil the given quantity of rove upon
the bobbins; then as the strap advances towards the base of the cone, (every point in this advance being
simultaneous with the commencement of a fresh layer of roving,) the speed of the wheel a is diminished,
causing that of the boss I to increase in the same ratio, and thus approximating the speed of the bob-
bins to that of the flyers, at every alternate motion of the traverse. In this way the irregularity due
to the varying diameters of the bobbins is compensated, and a uniform very slight tension maintained
upon the slivers between the flyers and the drawing rollers.
eee, a train of bevel-wheels and pinions for conveying the motion of the short shaft G to the mangle
pinion shaft C.
f g g, a train of spur-wheels and pinions (including change pinions) for conveying the motion of the
cone F, at once to the traverse and equational motions. It is obvious that to preserve the regularity of
the winding, the speed of the traverse or copping motion, as well as that of the bobbins themselves,
must be progressively retarded.
h hh, a train of spur-wheels for conveying the differential motion to the bobbin shaft N. The pinion
d on the boss I works into a wheel fixed to the end of the shaft B; this shaft has another spur-wheel h,
Figs. 1725 and 1732, upon its opposite extremity, which geers with h an intermediate wheel suspended
in a joint formed by the meeting of two pairs of arms; one of which have their centre of motion on the
shaft B, and the other upon the shaft N. Thus, when the latter ascends and descends in obedience to
the traverse motion, the arms move in a radial direction round their respective centres, and consequently
the suspended wheel h is kept constantly in geer both with the wheel on the end of the shaft B and
with the pinion on the shaft N. This will be clearly understood by observing the dotted lines in Fig.
1732, which denote the different positions of the bobbin lifter, and the corresponding positions of the
arms and intermediate wheel.
k m., a train of spur-wheels for conveying the motion of the driving shaft to the shaft E working
the cone motion, Fig. 1725.
n, is a spur-wheel on the end of the drawing roller, also working into the movable intermediate k,
which thus commands the drawing, the bobbin, and traverse motions. The train i k n, is called the twist
geering, and its object is to vary the speed of the front roller while the speed of the spindles remains the
same, and thus to put more or less twist into the rove as may be required.
oop, a train of wheels between the drawing rollers and the back shaft-p being a change pinion;
these, together with the train Y Z, at the opposite end of the machine, constitute the draught geering.
vr, small pinions connecting the detaining rollers together.
tu, a handle and small bevel-wheels working a barrel round which is coiled a chain attached to the
pulley frame for winding the rack, &c., towards the apex of the cone F.
vvwwyy, the fallers and geering for working them, as minutely detailed in a preceding description.
the flyers fixed upon the top of the spindles for twisting, guiding, and winding the rove upon
the bobbins.
The wet spinning frame.-With the exception of the hot-water trough and its adjuncts, this machine
bears a close resemblance to the throstle frame of the cotton manufacture, and like it, is employed for
the completion of the yarn, after being subjected to the processes of drawing and roving.
Although the principle of its operation be. for the most part, the same as that of the roving machine,
it is much less complicated than the latter, inasmuch as it dispenses with the gill apparatus, (which is,
of course, only applicable to parallel slivers,) and with the equational bobbin motion, which, in the pre-
sent instance, is rendered unnecessary by the circumstance of the yarn itself having attained a sufficient
degree of cohesive force to enable it, with the aid of a simple contrivance, to regulate the drag upon the
bobbins.
A very important improvement in the spinning of flax is the use of the hot-water trough, through
which the rovings are caused to pass in the act of spinning. By this means, the glutinous matter ad-
hering to the fibres is thoroughly dissolved, and a much finer, smoother, and more uniform thread than
could otherwise have been possible. is produced. There is an improvement in the method of driving
the spindles, by which one tape is made to communicate motion to four spindles, and another in the
method of working the traverse motion, as seen in the figures.
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FLAX, MACHINERY FOR PREPARING AND SPINNING.
Fig. 1734 is a front elevation, broken in the middle, for the purpose of exposing part of the geering
for working the traverse motion.
Fig. 1785 is an elevation of the geering end of the machine; and Fig. 1736 is a transverse section of the
entire machine.
Literal References.-A A, the frame
ends or standards of cast-iron.
B B, the middle support.
C C, longitudinal beams of cast-iron, on
which are supported
a a, the stands or framing of the rollers.
The bottom or drawing roller journals are
fixed, while the top or detaining roller
N
j purnals slide on the upper part of the
stands, and are regulated by screws, (see
dotted lines in Fig. 1736.) 80 as to adapt
the reach or distance between the draw-
ing and detaining rollers to the various
lengths of fibres. This distance should
always be a little more than the average
length of the filaments.
bb, the bottom or drawing rollers, usu-
Y
ally called the front rollers.
cc, the top or detaining rollers, usually
called the back rollers. Both front and
back rollers are made of brass cast upon
a wrought-iron shaft or axle, and fluted.
dd, the saddles for retaining the press-
ing rollers in their proper places. The
bushes or bearings of the top pressing
rollers are made to slide upon projecting
arms, in order to suit the various lengths
of reach. The top pressing rollers are
generally made of brass and the bottom
G
of box-wood, and both are fluted.
A
ee, are bolts fitted with adjusting
thumb-screws for attaching the saddles
1734.
dd, to
ff9 g, levers with weights for giving
SPALE-3 inches=5 feet.
the requisite pressure to the pressing
rollers.
H
hh, cranked axles extending the entire
length of the machine for relieving the
pressing rollers from the strain of the
weighted levers when the machine is at
rest.
ii, ratchet-wheels fixed upon the end
of the cranked axles for maintaining them
in the position in which they may be
placed.
DD, the wooden troughs surmounting
the machine, and through which the ro-
vings pass before reaching the detaining
rollers. These troughs are supplied with
hot water, and kept at a high temperature
by steam from a boiler.
E, the creel in which the roving bobbins
are placed vertically, in alternating rows.
F, a wooden rail surmounting the creel,
to which are attached
E
jj, the slender sheet-iron supports for
the top of the roving bobbin spindles, the
lower ends revolving in footsteps on the
top of the trough, Fig. 1736.
kk, the bobbins, as filled with loose
yarn by the roving machine.
illi, longitudinal brass rods for conducting the rovings into and through the troughs DD.
m m, is a flat brass rod, placed immediately above the detaining rollers, and extending the entire
length of the machine; opposite to each boss of the detaining rollers an indentation is cut in the rod m,
for the purpose of guiding the rovings. A small endless screw is cut on the end of the detaining roller
shaft, and geers with a worm-wheel p. Fig. 1734, which works on a stud fixed to the beam C, and has
R small heart-wheel formed upon its upper surface. A small steel pin n is fixed to the end of the rod m,
and is pressed against the heart by a drag-weight o, attached to it by a chain passing over a small pul-
ley. As the roller revolves, it produces a slow motion of the heart causing the rod m m, to traverso
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nearly the whole length of the boss, and thereby preventing the roving from wearing the surface of the
rollers unequally.
qq, the thread-plates or guides, having small notches opposite to each bobbin through which the
threads pass on their way from the drawing rollers to the eyes of the flyers. These plates are made
in separate lengths as may be convenient, and are hinged in order to enable the bobbins to be inserted
into or withdrawn from the spindles.
1735.
K
K
E
D
D
R
q
P
S
KAMAN
?
N
A
A
M
J
G G, are sheet-iron linings extending from the beam C to
H H, spouts formed under and within the rows of bobbins. These linings and spouts serve to collect
and withdraw the water which is thrown off by the centrifugal force of the bobbins.
1736.
K
K
E
D
D
70
10
10
a
B
B
G
C
V
T
и
H
H
A
X
t
OL
W
K
Consents
r
B
A
A
rr, the flyers for guiding and winding the yarn on
88, the bobbins, formed with a species of pulley on their lower flanges. In this machine the bobbins
are not driven independently of the spindles, for a reason which we have specified in our introductory
remarks. The natural tendency of the bobbins to wind on the yarn regularly is assisted by the follow-
ing contrivance:
tt, are drag weights, attached by pieces of string to loops on the back of the bobbin lifter; these
cords pass across to a plate with a serrated edge fixed to the front of the bobbin lifter, and press against
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FLOATING SECTIONAL DOCKS.
the grooves formed in the lower flanges of the bobbins. The friction thereby occasioned, which may be
varied by changing the length of leverage at which the weights act, gives the bobbin the requisite re-
tardation for winding on the yarn.
uu, the bobbin beams or lifters supported by the traverse rods x x, which are attached to bosses
upon the traverse shaft xx, by chains furnished with adjusting thumb-screws for adapting the bobbine
to the height of the flyers.
vv, are the spindle rails or beams, in which are inserted the steps and collars for the spindles to run in.
w, the spindles themselves, with their driving wharves or pulleys fixed to them.
I, is a bracket upon which works the strap-guide for starting and stopping the machine.
J. the fast and loose pulley fitted to the end of
KK, a long cylinder constructed of tin plates and extending the entire length of the machine, form-
ing a continuous drum for driving the spindles.
L, a balance pulley round which the tape passes for driving the spindles, and which keeps it at the
proper tension. The tape passes over the cylinder K, then over the balance pulley L, and round two
spindles on each side of the frame, thus causing one belt or tape to drive four spindles. Previously to
the introduction of this method, each spindle was impelled by a separate tape.
MNOPQRS, a train of spur geering, (0 being a change pinion,) constituting the twist geering and
conveying motion from the driving shaft to the front rollers on both sides of the frame.
TUV, a train of spur-wheels situated at the middle of the frame, and constituting part of the trav-
erse geering. T is a pinion fast upon the end of the shaft which carries the intermediate twist wheel
P, and which has a bearing in the middle support B. This wheel works through the intermediate U,
into V upon the mangle pinion shaft.
W is the mangle wheel situated at the opposite end of the frame to the twist geering, and actuated
alternately in both directions by the mangle pinion.
X. a small spur-pinion fixed to the axis of the mangle wheel, and working into a rack formed on the
top edge of
Y, a cast-iron horizontal bar working transversely in slides bolted to the inside of the end framing A A.
Each extremity of this bar is formed into a radial rack; these work into the eccentric spur-wheel yy,
fixed upon the traverse shafts z 2, imparting to the latter a graduated motion of rotation, which is com-
municated to the bobbin lifter by the mechanism previously described; causing the flyer to wind the
yarn upon the hobbin in a slightly spherical form.
a' d', a combination of wheels forming the draught geering, precisely similar to the draught geer-
ing in the other machines which have come under our notice.
FLOATING BRICKS, in imitation of those made by the ancients, were formed by M. Fabbroni, out
of a material which consisted of 55 parts of siliceous earth, 15 of magnesia, 14 of water, 12 of alumina,
3 of lime, and 1 of iron: this kind of brick does not become altered by fire, being infusible, and although
it loses 1 part of its weight, it is not in any way diminished in size: as these bricks are found to float
on water, they have been very much used where lightness of construction was desirable. See FIRE-
BRICKS.
FLOATING SECTIONAL DOCKS, Messrs. Burgess and Dodge, New York, patentees. These docks
are very powerful, being capable of lifting vessels of upwards of 2,000 tons burden, and are executed at
a comparatively small cost, being chiefly of timber.
These docks, instead of being fixed, and in one position, like the marine railway and screw docks,
may be towed to any vessel within a convenient distance.
Suppose that a ship is sunk, say in 5 fathoms water, it may be raised to the surface by hogsheads, or
slung by any of the usual modes; and, once got up to the surface, the sectional floating dock can be
readily introduced beneath it, and the whole towed together to the landing or shipwright's wharf.
The sectional floating dock derives its name from its consisting of distinct sections of timber framing
in the form of a floating dock, into which ships can enter. In the sections on each side are balance
tanks raised and lowered by means of a rack and pinion, and also tanks, which, by being filled with
water, cause the dock to sink, and by the water being pumped out enable it to be raised to any required
height out of the water, the ship resting on the platform within. On the top of the sections is machinery
for working the racks and pinions and pump-work.
Such is the general principle of the contrivance. Now to detail the construction. According to the
size of the vessel to be raised, any number of sections, more or less, may be used, as convenience
suggests. Each section is 92 feet broad externally, and 64 feet internally, and 23 feet long. The
section is 38 feet high externally, exclusive of engine house, and 28 feet high internally to the top of the
standards. The dock, it will be seen, is neither more nor less than a large floating timber vessel, and is
constructed of beams strongly bolted together.
Each section may be considered as consisting of three parts, two lateral scaffoldings or framings of
standards within which the balance tanks run, and a central platform connecting them. The object of
the lateral framing is to enable the balance tanks B to be run up and down, and to prevent the machines
from coming in contact with the water. Each lateral portion, Fig. 1737, consists of two external
standards G, 36 feet high and 12 inches square, and of four internal standards ff, 371 feet high and
12 inches square. These standards are at the bottom secured to the outside truss girders F, and on
their tops carry a platform on which the engine apparatus is placed. The standards are bound together
by proper tie-pieces, and are further secured to the outside truss girders F by a 12-inch beam 44 feet
long, F*. At the bottom of each lateral framing is a flooring on which rests a balance tank B, 191 feet
long, 10 feet broad, and 8 feet deep, being of a capacity of about 1500 cubic feet. The total capacities
of the fourteen tanks would therefore be 21,000 cubic feet. Besides these are water tanks within the
platform in which the pump rods t' work.
The platform is about 10 feet deep, and on the upper surface consists of two outside truss girders FF,
being about 70 feet long and 17 inches across, composed of two beams scarped together. Between these
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FLOATING SECTIONAL DOCKS.
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G
A
F
B
M
M
M
M
&
&
1737.
K
F
A
at
K
M
L
B
n
84
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FLOATING SECTIONAL DOCKS.
are a cross beam, 7 inches square, in the centre, secured to the keel beam P, and a cross beam on each
side D D, 9 inches square, for carrying the chock blocks E, and secured to the keel beams P. These
cross beams rest on joists or tie-pieces, 10 inches square. In the centre across are the two keel
beams PP, 241 feet long and 12 inches square, and which carry five keel blocks C. This upper plat-
form rests on the foundation truss girders F, by means of posts and timbers scarfed in, and is further
secured by four stout iron ties. The bottom truss girder F2 is 93 feet long, and formed in three por-
tions, well scarped, tied, and bolted together. These bottom truss girders extend under the lateral
framings, knitting together the whole structure.
1738.
o
n
1741.
A
DC
G
OC
R
The sections are connected together, in case of need, by double tie beams, which can be readily
slipped out, by withdrawing the nuts and screws by which they are secured.
On the cross beams DD, Fig. 1737, on each side is a rack and pawl, enabling the chock blocks E to be
readily moved, and secured by means of tackle. The chock blocks are 4 feet high and 3 feet 9 inches
wide. These receive the bottom of the ship; but in order to steady the sides there are side supports
on each side LL, worked by block and pawl M, 80 as to make the ship firm to the inner standards ff.
The object of the balance tanks B is to keep the dock steady and in an upright position. They con-
tain no water, and it is only necessary to keep them depressed to the level of the water, either in
sinking or raising the dock, and their resistance keeps the whole dock, with the ship, perfectly steady.
The lateral framings are furnished with two stationary spuds II, 34 feet high and 7 inches square,
provided, on one side, for 27f feet, with a rack plate. This spud is secured into the framing at top and
bottom, and is for the purpose of working the tank up and down by machinery, subsequently to be ex-
plained, and part of which is seated on the top of the tank B. Each lateral framing is also provided
with a ladder N, and an upper stage for the workmen.
On each side of the centre section is an engine house, which contains the machinery for working
the thrusting and pumping apparatus, and from which shafts run along the sections on each side. It
should be observed that the machinery on all the sections is covered in, although it is not 60 repre-
sented.
The engine house contains a tubular boiler, a, Figs. 1739 and 1740, like a locomotive boiler, with steam
pipe b, and exhaust pipe c, cylinder d, and valve box C. From the piston a cross-head carries a connecting
rod g, working on the crank h, which drives the main shaft i, on which is the balance wheel j From
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FLOATING SECTIONAL DOCKS.
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the main shaft a pinion and bevel wheel k and k' carry the motion to the shaft 1, which is the longitu-
dinal driving shaft, continued, as hereafter explained, along the sections for a length of 140 feet. From
this longitudinal driving shaft l, a wheel o, working by a belt on the wheel p, communicates the power
to the pumping geer on the shaft r, crank t, and pump-rod t', running down to the water tanks. This
geering can be thrown in and out by means of the movable pulley q, which by being raised or let fall
tightens or loosens the belt on o and p. The longitudinal shaft l also works the shaft w, by which the
thrusting geer is moved, and which by means of the wheels and pinions u, v, x, and y, put on or off by
the clutch z, works the tank and pinion J either upwards or downwards as may be required. The
shaft l is connected at each end by means of the universal joint m, and by the small circular shaft n,
with the longitudinal shafting on the end sections. By this means the different sections may be placed
at such distance from each other as the length of any ship may render necessary. It is to be observed,
that a necessity constantly occurs for sinking one or more sections lower than the others. This is also
provided for by the slip and universal joints.
1745.
n
m
m
n
The thrusting geer, Figs. 1742 and 1744, for raising and lowering the tank B, takes its motion, as men-
tioned, from the shaft by means of the bevel wheel, which moves the pinion at the head of the square
vertical shaft. On this shaft is a movable socket, with a square hole in it, and four friction rollers, 80
that the vertical shaft may easily pass through it. Beneath the friction rollers is a pinion, working into
the bevel wheel. This bevel wheel is on the horizontal shaft, secured into a framing on the top of the
platform of the tank B. The horizontal shaft carries a worm, working into a worm wheel, the shaft of
which carries a pinion J at each end, working into the spud J, which is kept in geer by a friction roller.
The number of spuds is twenty-eight, four on each section, or two for each tank. On the end sections
the machinery consists merely of a longitudinal shaft, the thrusting and pumping geer.
The process of taking a ship into the sectional floating dock is as follows The dock is sunk to any
required depth by opening the gates or valves with which each water tank is furnished, and the dock
necessarily sinks. The dock still being at the required depth, the ship is then introduced between the
vertical side framing, rests on the keel blocks C, and when supported on the sides by the chock blocks
E and side supports L, is ready for lifting.-Fig. 1737.
The valves which have previously admitted the water into the water tanks are now closed, the water
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FLOATING SECTIONAL DOCKS.
is pumped out, and the air again fills the tanks, and they rise, bringing with them the vessel to the
height necessary for repairs.
The vessel is taken out of dock by a repetition of the process of admitting water into the tanks.
The patent is for the general arrangement in the construction of the side balance tanks B.
1739.
Fig. 1787.-Elevation of a section.
BB, the balance tanks. C, the keel block. DD, cross beams supporting the chock blocks E.
EE, the chock blocks. FF, the outside truss girders.
ff, the inside standards of the main framing to guide the balance tanks B.
*F Beam securing the standards. G G, the outside standards of ditto.
1740.
P
m
W
t
II, the stationary spuds for working the tanks. JJ, pinions working in the racks on the spuds.
K K K, outline of a vessel in the dock, supported by the side supports LL, the chock blocks EE, the
keel block C, and the balance tanks BB.
LL, the side supports run up and down by the blocks and tackle MM.
00, engine houses on centre section.
cc, vertical shaft from the main shaft in the engine houses.
g, the worm working the wheel h. h, the worm wheel working the pinion J and the spud I.
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Fig. 1738.-Inner side elevation of a section.
Fig. 1745.-Plan of the engine and machinery at 0 on the centre section A 4 of the sectional floating
dock.
a, the tubular boiler. b, the steam pipe. c, the exhaust pipe. d, the cylinder. e, the valve-box.
g, the connecting rod working on h. H, the cross-head. h, the crank on the main driving shaft i.
i, the main driving shaft. j, balance wheel.
k k', the main bevel wheel geering, transmitting the power from the main driving shaft i to the
longitudinal driving shaft 1.
i, longitudinal driving shaft working the thrusting geer, and communicating along the sections by m
and n.
m m, universal joints connecting the shafts 11.
n n, small circular shafts working into the shaft I with a aleeve or socket and feather.
1744.
1743.
I
1742.
B
B
B
74
B
B
B
a, pulley or wheel on shaft I for setting in action the pumping apparatus, and connected by a belt
with p. p, pulley or wheel driving the pump shaft r.
q, a movable pulley for tightening or loosening the belt connecting o and p.
v, a crank shaft working the pump rods t'. 8, a balance wheel on the pump shaft r.
t, crank on the pump shaft r.
t', connecting rod from the crank t to the pumps in the balance tanks B B.
UVXY, wheels and pinions for changing the motion, making it slower or faster, and reversing the
action of the spuds I. uv, wheel and pinion on the longitudinal shaft 1.
xy, wheel and pinion on the thrusting shaft 10.
to, shaft carrying the change motion wheela, and working the thrusting geer.
, clutch for changing the motion on the shaft w.
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FLOOR CLOTH.
a' b' part of the thrusting geer taken from the shaft w. a', bevel-wheel on the shaft w.
b', pinion working on a' and moving c'. c', square vertical shaft of the thrusting geer.
Fig. 1741.-Plan of the machinery on the side sections A 1, 2, 3, 5, 6, 7 of the sectional floating dock.
Fig. 1739.-End elevation of the engine and machinery at o on the centre section A 4 of the sectional
floating dock.
Fig. 1740.-Side elevation of the engine and machinery at 0 on the centre section A 4 of the sectional
floating dock.
Fig. 1742.-Plan of balance tank B with machinery.
B, the balance tank. ff, the inside standards of the main framing to guide the balance tank B.
c, the square vertical shaft from the shaft 20.
d, small pinion working on the vertical shaft c, and on the bevel-wheel e.
e, bevel-wheel working on the worm shaft n.
f', movable socket of the shaft c, having a square hole in it, and four friction rollers on it.
n', worm shaft. g, worm working on the shaft n from the bevel e.
h, worm wheel worked by the worm g, and turning the shaft o.
o, shaft worked by h, and working the pinions JJ.
JJ, pinions working on the teeth of the spuds IL
II, upright stationary spuds for raising and lowering the balance tank B.
k, small friction roller for keeping the spud I in geer.
Fig. 1743.-Side elevation of machinery on the balance tank B.
Fig. 1744.-Enlarged front elevation of the pinion d, bevel-wheel e, and friction rollers f.
FLOOR CLOTH. This useful and ornamental manufacture was originally made of narrow canvas
sewn together like sail-cloth, to which successive coats of paint were applied; but the seams proving
inconvenient, a canvas was wove for the purpose, about four yards wide; it was then extended to seven
yards in width, and afterwards to nine, which is the widest at present made; but the common dimen-
sions of the oil cloths produced being 20 yards by 8, and 30 yards by 7. giving therefore entire pieces
of 160 and 210 square yards without seams. These canvases are stretched upon frames, and accessi-
ble over their whole surface by stages erected for the purpose these are the circumstances which render
the large dimensions of the manufactory requisite. The canvas being duly strained, is rubbed over
with pumice stone, which renders its surface smooth and even, and then brushed over with a weak solu-
tion size; when this is dry, the first coat of oil color is laid on, not with brushes, but with trowels, some-
thing in the manner of plastering; when this is dry a second coat follows it; and in this way seven
coats of paint are usually applied in succession, three on the back and four on the front. When the
cloth in this state, and of one color, is sufficiently dry, it is removed from its frame upon a large roller,
and carried to the upper part of the building to be printed; that is, to receive its pattern. This was
originally effected by a process of pencilling; but in the year 1780, there was introduced the great im-
provement of block-printing; by which the colors are more correctly laid on, and in greater body and
variety. The printing table, which is about 30 feet long, 4 wide, and 2 feet 6 inches high, is very
firmly constructed of deal timbers laid edgeways and clamped together, the surface being truly planed;
the roll of painted cloth is placed underneath it, and as it is unrolled it gradually passes over the table,
where it is printed, and is then drawn forward so as to hang perfectly free while drying. the height of
the building being such as conveniently to admit of this, without rolling, doubling, or folding the mate-
rial, which in these stages would of course injure it. The colors, which are the usual oil colors very
carefully prepared, are put on in succession with wooden blocks, which are made of pear-tree, box, or
holly-wood, and upon which the patterns are cut in relief; they are about eighteen inches square, and
are applied in succession over the whole of the surface of the cloth lying upon the printing table. Every
color is put on by a separate block, and much dexterity is required in so placing them that the patterns
may correctly interlace and join each other, without in any case overlapping or interfering to effect
this, the workman is aided by guide pins, or pitches, as they are termed, which direct him in placing the
block. The colors are first brushed or tiered upon hard cushions, from which they are transferred to
the block, and thence to the cloth; and, though many are often required, it is astonishing how much
effect is sometimes obtained by the judicious arrangement or mixture of two only, upon a third, which
forms the ground. It will be obvious, from what has been stated, that the weight of the finished oil
cloth, as compared with the naked canvas, is no unimportant criterion of its goodness; each square
yard when finished weighing from three pounds and a half to four or four and a half: this distinguishes
a good oil cloth from those which are vamped up and stiffened with size and other perishable materials.
Independent of the common application of oil cloths, it is not unfrequently advantageously employed
as a roofing material, especially for covering verandas and other light structures. When used for this
purpose, the canvas should be made of picked long flax, and thoroughly saturated with good oil paint.
FLOUR MILL See CORN MILL.
FLY FRAME. See SPEEDER.
FLY-WHEEL A large heavy wheel, used as a regulator or equalizer of motion, wherever either
the power communicated or the resistance to be overcome is variable. In the one case the fly-wheel
may be said to be a distributor of power. The communicated impulses act on the mass in motion, and
go to preserve the momenta, without disturbing very sensibly the regularity of movement. The effect
of one impulse is so absorbed or distributed in the momentum of the wheel, that its effect may be said
to have hardly been diminished before the next impulse is received. In the other case, or where the
fly-wheel is used to overcome a variable resistance, it may be considered a collector of power; the
power having been employed to get up the speed in the fly-wheel only, is retained in the mass in move-
ment; and the whole of the power expended, with the exception of that which has been lost through
friction and resistance of the air, can be brought to bear at any instant upon the resistance to be over-
come.
The applications of fly-wheels are very general;-there are few stationary engines without them.
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But it is usual in this country to communicate the power directly from the periphery of the fly-wheel,
either by making it a geered wheel or using it as a pulley or drum, and transmitting the power through
a belt or band. We know of no rules more accurate by which to calculate the dimensions of fly-wheels
for steam engines, than those given by Mr. Hann. They are as follows:-
RULES FOR THE FLY-WHEEL.
For the double-acting engine, the number of revolutions, or the number of double strokes per minute,
the mean radius and the horse-power being given.
To find the weight of the wheel.Rule 1. Multiply the number of horse-power by 2275, and that
product by n. Multiply the square of the mean radius by the cube of the number of revolutions per
minute.
Divide the former product by the latter, and the quotient will be the weight in tons.
The value of n given by M. Morin varies with the purposes to which the engine is applied. Thus, when
great regularity of movement is not required, as in saw-mills, grist-mills, the working of pumps, &c.,
n = 20 to 25. For cotton-mills spinning not less than 60, n = 30 to 50; for those spinning higher
numbers, n 50 to 60. For rolling-mills for making bar iron, with 6 to 8 sets of rollers, requiring an
engine of 80 to 100 horse-power, n = 20; for smaller mills, of 4 to 6 sets of rollers, and engines of 60
horse-power, n = for mills of 1 set of rollers for large bars, or 2 for small rods, and engines of 30
to 40 horse-power, n = 80.
To find the mean radius of the wheel.Rule 2. Multiply the number of horse-power by n, divide the
product by the area of the section of the rim, and extract the cube root of the quotient.
Divide 12.17 by the number of revolutions per minute, and multiply the quotient by the cube root
before obtained. The product will be the mean radius required.
To find the area of the section of the rim-Rule 3. Multiply 1802'9 by the number of horse-power,
and that product by n. Multiply the cube of the mean radius by the cube of the number of revolu-
tions per minute.
Divide the former product by the latter, and the quotient will be the area of the section.
For the double-acting engine, the number of single strokes per minute, the mean radius, and the
horse-power being given.
7σ find the weight of the wheel.Rule 4. Multiply the number of horse-power by 18200, and that
product by n. Multiply the square of the mean radius by the cube of the number of revolutions per
minute.
Divide the former product by the latter, and the quotient will be the weight in tons.
To find the mean radius of the wheel.-Rule 5. Multiply the number of horse-power by n, divide the
product by the area of the section of the rim, and extract the cube root of the quotient.
Divide 24.34 by the number of revolutions per minute, and multiply the quotient by the tube root
before obtained. The product will be the mean radius required.
To find the area of the section of the rim-Rule 6. Multiply 14423 by the number of horse-power,
and that product by n. Multiply the cube of the mean radius by the cube of the number of revolutions
per minute.
Divide the former product by the latter, and the quotient will be the area of the section.
For the single-acting engine, the number of revolutions, or the number of double strokes per minute,
the mean radius, and the horse-power being given.
To find the weight of the wheel-Rule 7. Multiply the number of horse-power by 11860, and that
product by n. Multiply the square of the mean radius by the cube of the number of revolutions per
minute.
Divide the former product by the latter, and the quotient will be the weight in tons.
7'o find the mean radius of the wheel.-Rule 8. Multiply the number of horse-power by n, divide the
product by the area of the section of rim, and extract the cube root of the quotient.
Divide 211 by the number of revolutions per minute, and multiply this quotient by the cube root
before obtained. The product will be the mean radius required.
To find the area of the section of the rim.-Rule 9. Multiply 93958 by the number of horse-power,
and that product by n. Multiply the cube of the mean radius by the cube of the number of revolu-
tions per minute.
Divide the former product by the latter, and the quotient will be the area of the section.
For the single-acting engine, the number of single strokes per minute, the mean radius, and the
horse-power being given.
To find the weight of the wheel.Rule 10. Multiply the number of horse-power by 94880, and that
product by n. Multiply the square of the mean radius by the cube of the number of revolutions per
minute.
Divide the former product by the latter, and the quotient will be the weight in tons.
To find the mean radius of the wheel.-Rule 11. Multiply the number of horse-power by 92, divide the
product by the area of the section of the rim, and extract the cube root of the quotient.
Divide 42.2 by the number of revolutions per minute, and multiply the quotient by the cube root
before obtained. The product will be the mean radius required.
To find the area of the section of the rim.-Rule 12. Multiply 75166 by the number of horse-power,
and that product by n. Multiply the cube of the mean radius by the cube of the number of revolu-
tions per minute.
Divide the former product by the latter, and the quotient will be the area of the section.
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672
FOLDING AND MEASURING MACHINE.
Ex. 1.-A double-acting engine makes 20 single strokes per minute, the radius of the fly-wheel is 15
feet, the horse-power is 60; what must be the weight of the fly-wheel, supposing the variation to be s'o
from the mean velocity 1
By
rule
(4,)
18200 X 60 X 40 18200 X 60 X 40
=
15' X 20"
;
225 X 8000
18200 X 60 40 364
=
=
2426.
225 X 8000
15
Ex. 2.-Wishing to diminish the number of strokes to 17 per minute, by how much must I increase
the weight of the fly-wheel to preserve the same regularity of motion
By
rule
(4,)
18200
X
50
X
20
18200
X
50
X
20
=
=
3706
tons,
the
weight
of
the
wheel
100 X 17'
100 X 4913
Hence, 3706 2426 = 12.8 tons, the weight by which the fly-wheel must be increased.
Ex. 3.-A double-acting engine makes 20 single strokes per minute, the horse-power is 60, the area
of the section of the rim is 15 feet; what must be the mean radius, supposing the variation to be 1'o
from the mean velocity ?
By rule (5) the mean radius is 24.34
60
X
20
24:34
9-2
X
=
11.2
feet
nearly.
20
15
20
Ex. 4.-A double-acting engine makes 20 single strokes per minute, the horse-power is 60, the mean
radius of the fly-wheel is 11.2 feet; what must be the area of the section
By rule (6) the area of the section is 14423 X 60 X 20 =
15.
(11.2)' X (20)
In the application of the fly-wheel to the steam engine, the varying effect of the power of the steain
communicated through the crank has been particularly regarded. The next consideration is to over-
come variable resistances, in cases where the moving power is not steam. Here it may be remarked,
estimating the force of any prime mover in horse-power, and taking the number of revolutions of the
fly-wheel, that the rules already given for finding the dimensions of fly-wheels may be applied to
mills where the resistances to be overcome are variable, as in the case of rolling-mills; in fact, the
values given to n in these particular cases were intended for a mill to be driven by water, and there-
fore may be somewhat too small when applied to the steam engine. For the smaller variations in
resistances, always experienced in the movements of machinery, no fly-wheels are necessary, when the
power is. constant, as in the case of water-wheels-the wheels themselves are sufficient regulators;
and whenever fly-wheels are necessary, the size, weight, and velocity of the water-wheel should be
taken into consideration, as it will be found to have considerable effect on the equalization of the
movement.
As to the position of the fly-wheel, it should be as near as possible to the prime mover if the power
is variable, and near to the resistance if this is inconstant, as the strain on the intermediate shafts would
frequently be very considerable. With regard to the diameter of the wheel, it will depend consider-
ably on position; but in some cases too small a diameter is to be guarded against. Tbus the tly-wheel
of an engine for a corn or flour mill. ought to be of such a diameter that the velocity of the circum-
ference of the wheel may exceed the velocity of the circumference of the stones, to prevent, as much
as possible, any tendency to back lash.
In conclusion, we give from M. Morin the rules for finding the weight of the rim of the fly-wheel
when employed to overcome the resistance of forge hammers.
To find the weight in tons of the rim of the fly-wheel on the cam shaft of a forge hammer.
For the largest forge hammers, striking 70 to 80 blows per minute-
Hammers weighing 3 to 4 tons, divide 240 by the square of the mean radius.
"
"
4 to 5
"
"
360
"
"
64
"
For trip hammers striking 150 to 200 blows per minute-
Hammers weighing 1000 to 1200 pounds, divide 108 by the square of the mean radius.
"
64
700
to
800
"
"
72
"
"
"
"
The quotient will be the weight of the rim of the fly-wheel in tons.
FOCUS in Geometry is that point in the transverse axis of a conic section at which the double ordi-
nate is equal to the parameter, or to a third proportional to the transverse and conjugate axis.
In optics. it is the space into which the rays of light are collected by a burning glass or mirror.
FOLDING AND MEASURING MACHINE Formerly, for the folding and measuring of cotton
cloth at the manufactories, hooks were universally used. These consist of two hooks or long needle-like
points, slightly curved upwards, inserted in a wooden bar, at a distance of a yard from each other; this
bar is supported on a stand at a beight convenient for the operative, and at least the width of the cloth
to be measured, from the floor, 80 that the folds may hang straight; the bar. for convenience, is often
permitted to have a movement horizontally. Attaching the cloth at one corner to one of the hooks, one
edge is drawn straight and hooked alternately on one and the other of the points, and in this manner
the whole piece is laid in folds of one yard each.
But latterly, in the larger manufactories and bleacheries, when the quantity of cloth prepared for the
market is large, the improved cloth measuring and folding machine" has been exten-ively adopted;
this machine was patented by S.C. Durgin in 1844, and is manufactured by Gay, Silver and Co., North
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FOLDING AND MEASURING MACHINE.
673
Chelmsford, Mass. Introduced first at Lowell, it is now employed in all the cotton factories in that city.
Since its first introduction, it has been improved in workmanship and detail; and, as an evidence of its
present capability, we give the statement of W. A. Kimball, overseer of the cloth room at the Atlantic
Mills, Lawrence, Mass. One machine will fold nearly 25000 yards of cloth per day, and more cor-
rectly than upon hooks, and ours has run 8 months without repairs."
From the specifications at the Patent Office we take the drawings and a description, which will give
an idea of the construction and working of the machine.
Fig. 1746 represents a plan or top view of the folding machine.
Fig. 1747 is a side elevation. Fig. 1748 is a vertical and central section.
The principal operative parts of the machine are similar to those of that patented by J. Spalding, of
Morristown, Vermont, in 1841. Durgin's inventions are certain improvements which render the opera-
tion of Spalding's machine more certain and expeditious.
A, Figs. 1746, 1747, and 1748, represent the main framework, which consists of two cast-iron sides or
frames, rising above and secured to the ends of a horizontal platform or table B.
The main driving or crank shaft C, supported in suitable bearings arranged near the upper part of
one side of the machine, is revolved by means of a spur geer D fixed upon one end of the shaft, and
actuated by a toothed pinion, impelled by the driving power.
E E are connecting-rods proceeding from bell cranks FF, (upon the shaft C,) and jointed to two of
the four upright sweeps QQQQ, which carry the folders. These upright sweeps are suspended in a
propersmanner at their tops, 80 as to be easily and alternately vibrated backwards and forwards. The
two sweeps at each end of the machine are connected together at or near the middle of each by a bar
G, while the movements of the sweeps that are connected to the crank shaft cause corresponding mo-
tions of the other sweeps. The folders H H consist of two metallic plates or bars, having arms II ex-
tending backwards and at right angles from them, which (arms) are so jointed to the lower ends of the
sweeps as to permit the folders to have a vertical movement with respect to the sweeps.
1746.
D
1749.
F
a
a
T
1750.
z
K
H
H
of
k
s
B
0
Z
l
T
m
K
The latch or retaining bars which confine the folds of the cloth down upon the platform B are seen
at KK. The first improvements consist in the mechanism by which the folders are alternately lifted
from and depressed upon the cloth in order to lay it in successive folds upon the platform. At or near
the centre of the inner side of each bar G a pulley L is arranged upon a pin M, projecting from the bar,
the said pulley turning upon the said pin. Upon each of these pulleys a chain or band N passes, hav-
ing its ends attached to collars 00, of two bent rods PP, each of which is jointed at one end to one of
the sweeps QQ, (or moves upon a pin inserted horizontally therein,) in the position, as seen in Fig. 1748,
and passes and moves freely at its other end through a vertical stud R, rising upwards from the arm
of the folder. Each of the collars 00 should be movable upon its rod, and so arranged as to be con-
fixed upon any desirable part of the rod by a set screw, so by moving the collars into suitable positions
on their respective rods the folders may be balanced when in the centre of the machine. Each pulley
has one end of a cam lever S attached to its side, and near its periphery, by means of a pin or stud a,
upon which the lever works. The cam lever has a semicircular slot b and a straight slot c formed on
its opposite end, as seen in Fig. 1748, and is connected to one of the sweeps Q by pins de, projecting
from the inner side of the sweep, and passing through the grooves bc. The two cam levers extend
from their respective pulleys in opposite directions to each other, being connected to the sweeps as in
Fig. 1746.
Now when the sweeps are moved to and fro by means of the crank shaft, the slots b and c in each of
the levers will permit the levers to accommodate themselves to the motion of the sweeps. and to turn
their pulleys L L around a short distance upon their axis, and thus gradually elevate one of the folders
85
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674
FOLDING AND MEASURING MACHINE.
above the platform, and the latch or retaining bar towards which the sweeps are moved, and at the
same time depress the other folder towards the platform.
During the elevation of either of the folders above the platform, the rods PP of the folder pass or
move longitudinally through the studs R R, and 80 as to cause the collars 00 of the rods to approach
towards the studs. So when either of the folders is depressed towards the platform, the rods PP of it
move in the opposite direction through the studs RR of it, and carry the collars away from the studs.
By this peculiar operation the balance of the folders is overcome, and that folder which is in immediate
action upon the cloth, or which is pressing the same towards one of the retaining bars or latches, is
depressed upon the cloth, and bears thereon with a slight force, and at the same time raises the other
folder above the cloth and the retaining bar, towards which the depressed folder is proceeding.
The next improvement consists in the mechanism by which the cloth is introduced into the machine,
and the overlap of the first fold produced. It is customary, in folding piece goods by hand, to turn
the end of the piece between the folds b and c, as seen at a, in Fig. 1749. By the ordinary folding
machine, the same has been arranged in the order as seen in Fig. 1750. The placing the ends between
the folds b and c, as in Fig. 1749, is what is termed the overlap of the first folds."
A small horizontal shaft f, supported 80 as to revolve in suitable bearings, extends across the machine
from one end of the frame to the other, in the position seen in Figs. 1746 and 1748. This shaft is put
in revolution by a pulley 2, arranged upon one end, which (pulley) is driven by a band proceeding from
the driving power, and the power which operates the shaft f should be 80 applied that it can be put in
action and thrown out thereof at pleasure.
There are two pulleys placed on the shaft f near its ends and at equal distances on each side of the
centre of the shaft, one of these pulleys being represented in Fig. 1748, at h.
1747.
r
a
Q
Q
n
D
1
e
2
M
1
N
A
N
P
K
R
02
P
1
di
H
B
0
M
A series iklmnopq of pulleys, arranged in the positions with respect to each other, and the pulley
i, as seen in Fig. 1748, and in the same vertical plane with one of the pulleys h, is disposed at each end
of the machine, they being supported by suitable shafts extending across or projecting from the frame-
work. Over each series of pulleys a band r passes, as seen in Figs. 1746 and 1748, and between the
bands rr a metallic or wooden bar 8 extends, having its two ends attached to the band, as represented
in Fig. 1746.
Small hooks or pins tt and c are inserted in the upper edge of the bar, upon which (hooks) the end
of the piece of cloth to be folded is hooked, 80 as to confine the said end to the bar. This being accom-
plished, the shaft f is to be put in revolution so as to cause the bands r r and bar 8 to move in the
direction denoted by the arrows in Fig. 1748, and the cloth into the machine until the bar 8 arrives at or
near the point t, when the revolution of the shaft f is to be stopped. The cloth thus drawn in will pass
over the horizontal shafts и v, and under the horizontal shaft w x. In its passage from the shaft w to
the shaft x it passes beneath a horizontal rod or bar y, which is supported at its ends by bent arms zz,
extending from the horizontal shaft x. Therefore, on turning the shaft x in its bearings, it causes the
bar y to descend in a curved direction towards one of the retaining bars k, and to press or carry the
cloth down with it, and to deposit it in a lap underneath the retaining bar. On unhooking the end of
the piece of cloth from the points of the bar 8 and putting the folders in operation, the end of the cloth
will be smoothed down upon the platform and then the overlap of the first fold will be produced.
In its passage into the machine the piece of cloth passes over 2 feeding roller a', which is arranged in
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FORCE.
675
the position denoted in the drawings, and moved by a belt or band b' passing around a small pulley c',
(fixed on the axis or shaft of the feeding roller,) and a large pulley d' fixed upon one end of a horizon-
tal shaft e', Figs. 1746, 1747, and 1748, which extends centrally under the platform from one end of the
machine to the other, and has a bevelled pinion f fixed upon its opposite end, which (pinion) works into
another bevelled geer wheel g' fitted upon the lower end of an inclined shaft h'. A bevelled geer i, fixed
on the end of the crank shaft, imparts motion to the inclined shaft, by engaging with another bevelled
geer H, fixed on the upper end of the shaft h. The central shaft e has two other shafts l' and m' ar-
ranged horizontally on opposite sides of it, as seen in Fig. 1748, and extending from one end of the frame-
work to the other. Each of the shafts Im has an arm n, (projecting from the centre in a direction to-
wards the shaft e,) and two arms projecting in opposite directions from its end respectively, one of the
latter arms being seen at O, Fig. 1748. Each of the retaining bars rests upon two of the arms O', by
means of suitable guides of the retaining bar projecting vertically through the platform and resting
upon the arms 00. The central arms n of the shafts I'm' are alternately depressed by cams or
wipers p, fixed upon the central shaft; the depression of the said arms elevating the retaining bars.
The surface of the roller a should move a very little faster than the cloth does, as it (the cloth) is drawn
by the folders over the guide shafts w v in order that the portion of the cloth which is between the
feeding roller a and the shaft u may hang loosely between the two rollers, and the feeding roller do all
the work of drawing the cloth towards itself, and thus freeing the folders from the strain in consequence
thereof; thereby enabling them to perform their operations with certainty and ease.
1748
m
Q
Q
Lo
T
c
F
G
o
W
N
A
A
N
R
P
o
P
R
K
H
I
H
K
B
m
c
Having thus described the machine, Durgin claims the mechanism by which the folders are elevated
and depressed, the same consisting of the pulley L, cam lever S, bent rods PP, chain or band N, and
parts as before described, as combined with each other and applied to the folders and sweeps. Also
the mechanism by which the cloth is introduced into the machine, and the 'overlap of the first fold"
produced, the same consisting of the endless band rr, (with the pulleys and shafts arranged substan-
tially as described,) and cross bar S, or machinery of similar character in combination with the depress-
ing bar y.
Also the peculiar method of feeding the cloth into the machine so as to present it to the action of the
folders as required by them, and with little or no strain upon them, viz. by supporting the cloth on one
or more horizontal rods or shafts u v, (placed above the folders,) in combination with giving to the sur-
face of the feed rollers a motion sufficiently increased beyond that of the folders, to cause that part of
the cloth which is between the supporting rod or rods and the feed roller to be loose or hang down in
proper quantity, to readily yield to the irregular motion of the folders over the platform, caused by the
cranks of the shaft which operates the sweeps of the said folders.
FORCE. Force is the cause of motion or change of motion in material bodies. Every change of
motion, viz. every change in the velocity of a body must be regarded as the effect of a force. On the
other hand, rest, or the invariability of the state of motion of a body, must not be attributed to the ab-
sence of forces, for opposite forces destroy each other and produce no effect. The gravity with which
a body falls to the ground still acts, though the body rests; but this action is counteracted by the solidity
of the material upon which it reposes.
Forces that are balanced, 80 as to produce rest, are called statical forces or pressures, to distinguish
them from moving, deflecting, accelerating, or retarding forces; i. C. such as are producing motion, or a
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676
FORCE.
change in the direction or velocity of motion. This distinction is wholly artificial, for the same force
may act in any of these modes; it may sometimes be a statical, and sometimes an accelerating force ;
but it is convenient to confine our attention in the first instance to forces in a statical point of view.
Statical forces can, of course, be compared only with each other, but the ratio between any two quan-
tities may be represented by the ratio between two other quantities, however different in kind from the
first two: thus, two pressures may have the same ratio as two lines, or two surfaces, or two bulks. or
two times, or two numbers. Now, when we represent magnitudes of any kind by numbers, we in fact
compare them with some fixed or standard magnitude of the same kind, which we represent by the
number 1: thus, the units commonly used for comparing lengths, are inches, feet, miles, &c.; and so
also the units of pressure are ounces, pounds, tons, &c.
In strictness, however, these terms do not properly express units of pressure, but of mass, (or quantity
of matter;) and they are used as standards of pressure simply because the earth's attraction on a
given quantity of matter is always the same at the same place, and differs but slightly in different
places. But the same mass, in a different situation, (as regards latitude, or level,) would gravitate with
a rather greater or less pressure. Mass must not be confounded with weight, because the same names
are applied to the units of both for, in fact, the units of pressure are quite distinct from, though founded
on, those of mass; just as the latter are derived from those of length, and all from that of time; the
connection being as follows:-
1. A pound pressure means, that amount of pressure which is exerted towards the earth, in the lati-
tude of London and at the level of the sea, by the quantity of matter called a pound.
2. A pound of matter means a quantity equal to that quantity of pure water which, at the tempera-
ture of 62° Fahrenheit, would occupy 27727 cubic inches.
3. A cubic inch is that cube whose side taken 39-1393 times would measure the effective length of a
London seconds pendulum.
4. A seconds pendulum is that which, by the unassisted and unopposed effect of its own gravity,
would make 86,400 vibrations in an artificial solar day, or 86163.09 in a natural sidereal day.
Forces may also (like any other magnitudes) be represented by lines of definite lengths. A unit of
length being taken to represent the unit of pressure, the length of the line represents the magnitude
of the force but the line has this great advantage over a number,-its direction represents the direc-
tion of the force; and its commencement or extremity, the point at which the force acts, or its point of
application: thus, by a line, the force is completely defined in all its three elements; while a number
can only represent one of them, viz. its magnitude.
In this way forces can be brought under the domain of mathematical science, geometry serving to
investigate their various relations by means of lines, arithmetic by means of numbers, and algebra and
trigonometry by the properties common to directions and magnitudes of all kinds.
If two forces be in equilibrium at a point; they must be equal in magnitude, and opposite in direc-
tion. But whatever number of forces may act upon a point, and whatever their directions, they can
only impart one single motion in one certain direction. We may, therefore, incorporate all these single
forces into one force, or resultant, capable of producing the same mechanical effect as the forces them-
selves, which are called the components.
When any number of forces act at a point in the same straight line, and in the same direction, the
resultant is equal to their sum; if the forces act in opposite directions, the resultant is equal to their
difference.
When two forces act upon a point in different directions, the resul-
A
tant is found more easily by the geometrical method. It is obvious,
1751.
in the first place, that the line representing the resultant must lie in
the same plane which contains the directions of the two forces for if
a
not, on which side of the plane should it lie 1 There is evidently
nothing to determine it to one side more than the other. For the
same reason, when the forces are equal, the resultant must bisect the
angle between their directions, for it cannot be nearer one than the
other. Moreover, in all cases, whether equal or not, the nearer they
coincide in direction, the greater will be the resultant, and vice versa ; P
C
since their exact coincidence makes it equal their sum, while their ex-
act opposition makes it equal their difference. But it is doubtful
whether elementary mathematics will carry us further than this with-
out the aid of experiment, which teaches us the following beautiful law.
Let the point P, Fig. 1751, be acted on by two forces, pressing in
the directions PA and PB. From the point P, upon the line P A,
measure off any length Pa; and from the point P, upon the line P B,
b
take a length Pb bearing the same ratio to P a that the force B bears
to the force A. The easiest way to do this is to make the lines Pa,
Pb, contain respectively as many units of length (inches or feet, for
B
example) as the forces A B contain units of force, (ounces or pounds, for example.) Through a draw a
line parallel to PB, and through b draw a line parallel to PA, these lines will meet at some point c.
We thus get a parallelogram P and the line Pc, called its diagonal, will represent a single force
acting in the direction PC, and consisting of as many units of force as the line Pc contains units of
length; and this force will produce upon the point P the same effect as the two forces PA and PB
produce acting together.
This method of finding an equivalent, or the resultant of two forces, is called the parallelogram of
forces, and is thus concisely expressed :- If two forces be represented, in magnitude and direction, by
the sides of a parallelogram, an equivalent force will be represented, in magnitude and direction, by its
diagonal." The two forces are called, the components of the resultant.
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FORCE.
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Any number of forces, acting at one point, can be compounded by the same rule. For instance, let
the body x, Fig. 1752, be pressed at once by the three forces whose directions are expressed by the
arrows A BC, and their magnitudes by the lengths x a, x b, xc. We may first compound any two of
them, (such as A and B,) by completing the parallelogram x a db, by which we find that the direction
of their resultant is x d, and that its magnitude is to their magni-
1752.
tudes as the length x d is to the lengths xa, x b. We may then
compound this resultant with the remaining force xc, by complet-
a
ing the parallelogram x dce, the diagonal of which, viz. xe, will
represent both the magnitude and direction of the general result-
ant of all three forces; so that a force of the magnitude expressed
by this length xe, and acting in the direction e x, would balance
those three forces. Of course the resultant of any greater number
of pressures might have been found in the same way, by combin-
ing two at a time.
C
In this problem it matters not whether the directions of the
forces lie all in the same plane or in different planes. In the latter case, the three lines x a. x b, xc
would form the three edges that meet at one solid angle of a parallelopiped; and by completing this
solid figure, as shown by the outer dotted lines of Fig. 1752, its diagonal x e will represent the result-
ant. Hence, whether we regard the lines of this figure as they really lie flat on the paper, or as the
projection or picture of a solid parallelopiped, the law is equally true. The same process is of course
capable of being extended to any number of forces in different planes.
It would scarcely be possible to arrive at some of the simplest results of its application to every
branch of physics, if recourse were not constantly had to the inverse problem of the resolution of forces.
It is constantly necessary to consider a force as capable of being resolved into two or three distinct
forces, having different directions; for it is evident that we may substitute for any given force, any num-
ber of other forces, having any given directions, (not opposite to each other ;) for we may make the line
L e the diagonal of any number of parallelograms, or parallelopipeds, having their sides running in any
proposed directions. When their directions are decided on, their lengths will be discoverable : and thus
we shall know both the directions and magnitudes of the forces into which, for convenience sake, the
whole, or resultant force, has been resolved.
Examples of the composition of forces are of constant occurrence, as in the exertions of our limbs, the
action of the various tools and implements which we employ, and the external actions in which we par-
ticipate. It is frequently of importance to consider whether the component forces are employed so as
to produce the best resultant; that is, one acting in a direction most available for the object intended
to be accomplished, and with as small an expenditure of force as possible.
As a familiar illustration of the composition of forces, take the flying of a boy's kite. To counteract
(permanently) the force of gravity which would bring it to the ground, two other forces at least are
required-viz. the wind, and the resistance of the string or of the point where it is fixed or held. The
wind alone would keep it suspended, but only for a time-viz. until the kite had either turned its edge
to the wind, (so as to be pressed no more on the under than on the upper side,) or else had become
vertical, so as to be pressed only horizontally and not upwards. If the kite had no tail, the former
effect would rapidly ensue, and with a tail the latter would be equally certain. It is necessary, there-
fore, that the kite be inclined, and this is effected by the string being attached at such a point as to
leave more surface (and therefore, a greater pressure of wind) below the point of attachment than above
it. This excess of pressure on the lower half drives it to leeward, but only to a certain extent, where it
is counterbalanced by the weight of the tail. The horizontal force of the wind W, Fig. 1753, the inten-
1753.
w
s
S
sity of which is represented by the line 0 w, must be resolved into two portions, one parallel, and the
other perpendicular to the surface. The former portion o a has no effect; the kite is pressed only by
the other portion, in the direction o b, in which direction it would move, if it maintained its inclined po-
sition, and were subject to no other force than the wind. But there are two other forces, the string
and gravity. Supposing the string to pull in the direction S, we shall find the intensity of this force
by resolving the whole effect of the wind on the kite represented by b, into two portions, o d perpen-
dicular to the string, (and therefore not resisted by it,) and oc, which must be balanced by an equal and
opposite force in the string, which will accordingly be represented by 0 & The action of the string and
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FORCE.
wind alone would therefore be to urge the kite in the diagonal o d of the parallelogram o b but
with this we must further compound the force of gravity, which (the kite being very light) we will re-
present by the short line o g, and this, compounded with o d, gives the resultant o F, in which direction
the kite will rise when subject to all three forces, in the degrees here supposed. If the wind suddenly
cease, the resultant of the string and gravity is found by compounding o $ with og, which gives o e as
the direction in which the kite would then be pulled; and this compounded with the effective portion of
the wind's force, viz o b, will give 0 F as before. In this direction, then, the kite will, under these cir-
cumstances, rise till it has attained a position where the three forces b, o 8, and og, are in equilibrium,
i. 6. where each is equal and opposite to the resultant of the other two, in which case we should on our
construction find o F= 0, or the point F would coincide with o.
In order to raise the kite to its greatest altitude, the most advantageous angle for the kite to form
with the horizon is 54° 44'; which is the same as the rudder of a ship should make with the keel, in
order that the vessel may be turned with the greatest facility, supposing the current to have a direction
parallel with the keel; and the same that the sails of a windmill, and the vanes of a smoke-jack or of a
screw-propeller, should make with the plane of their rotation.
Forces in a plane.-In order to find the mean force P for a system of forces P₁ P, P₃, &c. by the re-
peated application of the parallelogram of forces, we may resolve them two and two and so on, till but
a single force remains. The forces P₁ and P2, for example, give from the parallelogram M P₁ Q P2, the
mean force MQ=Q; if this be joined to P2, we have from the parallelogram M Q R P2, M = R; and
this last again forms a parallelogram with P. and gives the force M P = P the last, and the resultant
of the four forces P₁ P, P, P4.
It is not necessary, in this way of composing forces, to complete the parallelogram, and draw its
diagonal. We may form a polygon M P₁ QRP, whose sides MP₁, P₁ Q, Q R, RP, are parallel and
equal to the given components P, P, P, P4 the last side MP completing the polygon will be the mean
force sought, or rather its measure.
This simple and elegant theorem is called the Polygon of Forces. By this, any number of statical
forces are represented in direction and magnitude by the sides of a polygon, taken in order; and they
will, when applied to one point, produce equilibrium.
1755.
1754.
R
M
d
c
b
P.
OLE
H
P
N
Q
0
R
To make this theorem clearer, attach a number of pulleys to a vertical plane, such as an upright
board, and carrying over them the lines which represent the forces, and attach weights to their ex-
tremities, as in Fig. 1755. Then take any part A a on the string A m, and from a on the board, draw
a line parallel to the string A n, and take a part a b upon that parallel, such that A a is to a b, as M is
to N. Again, through b draw a parallel to the string A o, and on that parallel take a part b c such that
ab is to b as N is to O. In like manner, draw c d parallel to A p, and such that bc : d : o : P; and
draw d parallel with A q, and bearing the same relation to the other lines that Q bears to the other
weights. Finally, join the points e and A by a right line. A single force R, acting in the direction of
the line e A. and having the same ratio to each of the other forces as the line e A has to the side of the
polygon, which is parallel to that other force, will produce a pressure on the fixed point A equivalent
and opposite to the combined actions of the forces MNOPQ This may be proved by attaching any
weights at random to the various strings, and (when they have settled in equilibrium) making the con-
struction above described, beginning with any side of the polygon, and making all its sides, except one,
parallel with their respective strings, and with lengths proportional to their respective weights. The
remaining side will then be found to lie always in a straight line with the remaining string, and to have
the exact length proportioned to the remaining weight.
Parallel forces.-It is evident that forces may be made to act side by side with quite as much effect
as in the same straight line. Two horses drawing a cart may of course be placed side by side, or one
before the other, and the effect will be the same. Hence, the resultant of two parallel forces, acting in
the same direction, is equal to their sum; it has the same direction with them, and when they are equal,
is applied at a point midway between their points of application. But when they act in contrary di-
rections, they have no simple resultant, for they tend to produce rotation, and this tendency cannot be
counterbalanced by any single force.
When two parallel but unequal forces are supported or balanced by a third, it must be equal to their
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sum, it must act in the contrary direction, and must be applied at a point nearer the greater force than
the less, its distances from them being inversely as their intensities.
Thus, in Fig. 1756, when the three forces at B A and a are
in equilibrium, B A the distance A a: the distance B a.
1756.
When one point of a rigid body is supposed to be immov-
ably fixed, the effect of any forces applied to that body can
B
n
only be to turn it round the fixed point, as a centre of mo-
tion; and when two points are fixed, the motion can only be
round the line joining them, which thus becomes an axis.
Now, as has been said above, two forces which tend to turn
the body in contrary directions will be in equilibrium if their
intensities are inversely as their distances from the centre or axis. But in every inverse proportion, the
product of the first and second terms is equal to the product of the third and fourth; or the product of
the first and third = that of the second and fourth. Thus, instead of saying that the forces A and B
are inversely as the distances a A and a B, we may express the same thing by saying that the product
of the force A X the distance a A = the product of the force B X the distance a B. Thus, if a straight
bar be balanced, as in Fig. 1756, and, at the distance of one foot from its fulcrum, or point of support, a
weight of 12 pounds be suspended, it will be found that this weight will be balanced by a weight of 6
pounds, distant 2 feet on the other side of the fulcrum; or by a weight of 4 pounds at the distance of 3
feet; or by a weight of 3 pounds at the distance of 4 feet. Now by multiplying these weights by the
number of units (feet) representing the distances from the centre, we get in each case 12; thus 6 pounds
at 2 feet = 12 pounds placed at 1 foot, or 6 X 2 = 12 X 1. In like manner, 4 pounds at 8 feet, or
4 X 3 = 12; and 3 pounds at 4 feet, or 3 X 4 = 12.
These products are called the moments of the force.
It is evident, also, that by increasing the number of forces on each side of the axis, the body will be in
equilibrium, provided the sum of the moments of those forces which tend to turn it round in one direc-
tion, be equal to the sum of the moments of the forces which tend to turn it round in the other
direction.
As this principle may be considered as the basis of mechanical science, it is desirable to illustrate it
by another method. If two weights in equilibrium, as in Fig. 1756, at the extremities A and B of a
bar supported on an axis a, passing through its centre of gravity, be made to oscillate gently through a
small space, it is evident that the spaces moved through by the two ends of the bar will be directly as
their distances from the axis; for, the angles A a m and B a n being equal, the arcs A m and B n, are as
their radii a A and a B. For instance, if the weight B be 12 pounds, suspended at 3 inches from a, its
moment may be expressed by the number 36; and it will be balanced by a weight of 6 pounds, 6
inches from a, because its moment is also 36. Now if these two weights be made to oscillate through
a small space, such as B m for the weight which descends, and A n for the weight which ascends, the
latter space will be only half the former, because it bears the same ratio to a B (or 8 inches) that A m
bears to a A, (or 6 inches.)
Hence, if B n be one ineh, A m will be two inches, and the products of these two quantities with their
respective weights will be equal to each other; that is, the effect of 12 pounds moving through 1 inch,
or of 6 pounds moving through 2 inches of space, is the same. And though we are not now concerned
with motions, but with pressures, the same principle applies to them. Any two pressures, however un-
equal, (a pressure of 1 pound and one of 1000 pounds, for instance,) will balance each other, if they are
so applied that the motion of the first through 1000 inches would be necessarily accompanied by a mo-
tion of the second through one inch, and vice versa.
This principle is known under the name of the principle of virtual velocities, and is that which regu-
lates the action and constitutes the efficacy of every machine in which power is employed to overcome
weight or resistance. In the composition of machines it is usual to speak of six mechanical powers;
namely, the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw; although
in reality these contrivances are but applications of the principle of virtual velocities, whereby a small
force acting through a large space, is converted into a great force acting through a small space. But
in this there is no gain of power, neither is there any loss; the advantage is in its application. Every
pressure acting with a certain velocity, or through a certain space, is convertible into greater pressure,
acting with a less velocity, or through a smaller space; but the quantity of mechanical force is not
altered by the transformation, and all that the mechanical powers can accomplish is to effect this trans-
formation.
Thus far we have regarded force simply as that which is necessary to oppose or balance force. We
are now to consider it as the cause of change of motion. Force, in the sense in which we have already
used it, is not required for the maintenance of motion, but only for its change-i. e. for effecting, 1st, a
change of state from rest to motion, or from motion to rest; 2d, a change in the velocity of motion, either
by accelerating or retarding it; or 3d, a change in its direction, by deflecting it upwards, downwards, to
the right, or to the left. The inertia of matter is only another mode of impressing this idea. And since
matter is inert, that is, has no tendency either to rest or motion, a body impressed with a motion must
persist in that motion, in a straight line and with uniform velocity, for ever, unless some new force act
upon it, either to change its state, its direction, or its velocity; for it cannot of itself change either its
state of rest or its state of motion, its velocity, or its direction. This is inferred from experiments and
observations on all the motions presented to our notice either in the heavens or on the earth, and is
known to be true, because any other law which can be substituted for it will be incompatible with some
or all of those motions.
We are therefore to regard as being in equilibrium, not only such bodies as are at rest, but also such
as are performing uniform rectilinear motion; for it is only while their velocity or direction is changing
that the forces acting on them can produce a resultant pressure; and as long as this pressure remains
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unbalanced, the motion will continue changing in velocity, or direction, or both; whenever it becomes
straight and uniform, the resultant of all the forces acting on the body = 0. Thus, when a train or a
steamboat has started, its velocity continues for a certain time to increase, because the forces that urge
it forward exceed the friction in one case, or the resistance of the water against the bows of the boat in
the other; but these opposing forces are dependent on the velocity and increase, because it increases so
that they presently become equal to the forward force imparted by the engines, and then the motion
becomes uniform, and the body, though moving at its full speed, is as completely in equilibrium as when
it was at rest. Thus the motive power is required, not to maintain the motion, but to maintain equi-
librium with the opposing friction or resistance. The motion is maintained because the body has been
set in motion, and, being inert, has no tendency of itself to alter that state; and also because any alter-
ation of velocity would, by increasing or diminishing the resistance, while the steam power remains
unaltered, leave a portion of the former or of the latter unbalanced, and this unbalanced force, acting
against or with the direction of the motion, would retard or accelerate it till the former velocity was re-
established. Thus the equilibrium is stable, or tends, when disturbed, to restore itself.
The dynamical effect of force being a change in motion, a continued force or pressure must produce a
continuous change, whether in velocity or direction The simpler effect of a sudden change of velocity,
or an angular deflection, can only be produced by an impact, or instantaneous exertion of force.
The greater part of the forces which impart motion to a body act directly upon only a few of its
molecules: thus, when a billiard ball is struck with the cue, we touch only a small portion of its surface.
As all the parts of a body are set in motion by an impulse communicated to a few only of its mole-
cules, it is clear that there must be a diffusion of motion from the parts acted on over all the other parts
of the body before it can begin to move. When this is not the case, the part struck is compressed, or it
is chipped off, and performs its journey alone, leaving the mass behind; but when the force has time to
be propagated through all the particles, the body is then impressed with a motion common to all its
particles.
When a force has acted upon a body, and the motion has diffused itself over all the molecules, 80 as
to impress them with a common velocity, the force has done its work; it has produced its effect, and
may be said to have passed from the moving power, or source of motion, into the thing moved. Thus
a stone projected by the hand, describes a certain path in space in obedience to the force which has
acted upon it once for all, and then ceased, leaving the force thus impressed to do its work. Now, if
the stone in its progress met with no other form of matter at rest or in motion-if, in short, no other
force acted upon it, it would continue to move with the same velocity and in the same direction for-
ever.
But the same force does not produce the same effects on different bodies. The charge of powder
capable of projecting a small shot, for example, may scarcely produce the slightest motion in a cannon
ball. And it is an established principle in mechanics, that when the same force acts upon different
bodies free to move, their velocities are in the inverse ratio of their masses, or of the quantity of matter
of which they are composed. Thus the same charge of gunpowder which would project leaden balls
whose volumes or masses were as 1, 2, 3, 4, &c, would impart velocities to them as the numbers 1, 1,
1. 1, &c.; hence it will be seen that the mass multiplied into the velocity gives in each case the same
number: in the first case, 1 X 1=1; in the second, 2 X = 1, and 80 on. When there is no friction,
the smallest impact is sufficient to impart motion to the largest mass; but only, of course, a very slow
motion. This product of the mass of a moving body by its velocity, is called the momentum, or moving
force, or quantity of motion. The same impact always gives the same quantity of motion, whatever
may be the body which it impels; so that the true measure and characteristic of an instantaneous force
or impact is the quantity of motion it is capable of imparting. Thus we may describe an impact by
saying that it is equal to 50 pounds moved 1 foot per second, or 1 pound moved 50 feet per second, or
2 pounds moved 25 feet per second, &c., &c, all meaning the same thing.
In ordinary language, the force of any moving body means its momentum, or the impact required to
stop it, or to impart the same quantity of motion to a body previously at rest. But the useful effect is
in most cases proportional, not to the momentum, but to the vis viva. Hence-1. When equal masses
are in motion, their forces are proportional to their velocities. 2. When the velocities are equal, their
forces are proportional to their masses, or quantities of matter. 3. When neither the masses nor
velocities are equal, the forces are in the proportion of both taken jointly, that is, the proportion of their
products.
Thus the force of a moving body, or the work which it will perform in a given time, (that is, its mo-
mentum,) varies as its velocity multiplied by its weight; but its whole accumulated force, or the total
amount of work which it will perform, no matter in what time, in being brought to a state of rest, (that
is, half its vis viva,) varies as the square of its velocity multiplied by its weight. In order to illustrate
this, let us suppose a railway train of a certain weight in motion upon a perfectly level and straight
railway, and let us assume that the resistances opposed to its motion are the same, whatever may be its
velocity, the practical incorrectness of this assumption not affecting our present object. Imagine the
velocity of the train to be fifteen miles per hour, and let it be desired to bring it to a state of rest at a
station which it is approaching suppose that the engine driver, judging from experience, shuts off the
steam at a distance of a mile from the station, and that the resistance experienced by the train in
moving over this mile is just sufficient to bring it to rest at the station, the time occupied in passing
over the mile being six minutes. Now if we again suppose the same train to be moving with a velocity
of thirty miles per hour, and it be desired to stop at the station, then, the resistance being the same as
before, it will in this case be necessary to shut off the steam at a distance of four miles from the station,
in order that it may be brought to a state of rest there, and the time which the train will occupy in
passing over these four miles will be twelve minutes. Again, let two bodies, both of the same weight,
be projected upwards, one with double the velocity of the other, and suppose the resistance of the air
removed, and only the force of gravitation, perfectly uniform in its action, to be opposed to the motion
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of the bodies then will the body projected with twice the velocity rise to four times the height, against
the same resistance, before being brought to a state of rest, but it will occupy, in doing so, twice the
time similarly occupied by the slower body.
When two masses moving in the same direction impinge one upon the other, and after impact move
together, their common velocity may be determined by multiplying the numbers expressing the masses
by the numbers which express the velocities; the sum of the two products thus obtained, divided by the
sum of the numbers expressing the masses, will give a quotient expressing the required velocity.
For example, if a musket-ball weigh one-twentieth of a pound, and its velocity on being fired be 1300
feet per second, if it strike a cannon-ball of 48 pounds, suspended by a string, it will set it in motion;
and the common velocity of the two is to that of the bullet as 20 is to 48 + or as 1 is to 961; the
1300
common velocity of the two is, therefore, 961 or
about
1}
feet
per
second.
When a musket-ball strikes against a large stone, or is fired at a mountain, it communicates both to
the stone and the mountain a certain velocity, small indeed, and not measurable unless we knew the
mass of the mountain in addition to other particulars. In fact, motion can only be destroyed by motion;
resistances and friction disperse it, but do not destroy it.
The resistance which a moving body meets with in the air, or in the water, is only an effect of the
transference of motion. A body moving in water must constantly displace a portion of the fluid equal
to its own bulk, and the amount of motion thus communicated to the water is 80 much lost by the
moving body. It is generally admitted in such cases that the resistance is in proportion to the square
of the velocity of the moving body. When the velocity is doubled, the loss of motion by resistance is
quadrupled, because not only is there twice as much fluid to be moved in an equal time, but it has to
be moved with twice the velocity. So also when the velocity is trebled. the moving body meets three
times the number of particles, to which it communicates three times the velocity, thereby occasioning
nine times the loss. The resistance to a body moving in water is, therefore, about 800 times greater
than if it were moving with the same velocity in air, for it has to move 800 times as much matter in the
same time. But if the motion in air were 28 times faster than in water, the resistance would be about
the same, for 28 times the velocity generates 28 times 28 times times) the resistance.
Action and reaction.-Action and reaction are equal and opposed to each other. This law not only
prevails in reference to forces produced by contact, but also in the so-called forces of attraction and
repulsion; amongst which the magnetic force and gravity itself may be ranked. The force with which
the moon is attracted towards the earth (gravitation) is equal to that with which the moon reacts upon the
earth. The force with which a workman draws or pushes at a machine, &c., reacts upon the workman
and strives to move him in the opposite direction. When a body impinges against another, the pressures
are reciprocally equal on each of the bodies.
Effects of continued forces-uniformly accelerated motion.-One cannot fail to be struck with the
different degrees of rapidity with which bodies fall through the air. A piece of gold falls rapidly. and
a dry leaf very slowly; and the popular reason for this difference is, that the gold is heavy and the leaf
light: this, however, is not the true reason, for if the gold be beaten out into a thin leaf, neither its
absolute nor its specific weight is diminished, but the time of its descent through the air is greatly pro-
longed. The fact is, that every body falling through a fluid is continually subject to two opposite
forces; 1st, its weight, which is constantly uniform, and acting alone would constantly accelerate the
fall, and 2d, the fluid resistance. Now the gold presenting a larger surface when beaten out than in the
lump, far more resistance is opposed to the leaf than to a thick piece of equal weight, moving with
equal velocity.
The fall of a heavy body from a height is a uniformly accelerated motion, because the attraction of
the earth, which is the cause of its fall, never ceasing to act, the body gains at each instant of its fall a
new impulse, whereby it receives additional velocity, so that its final velocity is the aggregate of all
the infinitely small but equal increments of velocity thus communicated. Hence, the velocity of a falling
body at the end of two seconds is twice that which it had at the end of one; at the end of three
seconds three times that which it had at the end of one, and so on. Now, it has been ascertained that
a body falling freely through space by the force of gravity acquires at the end of the first second a
velocity such as would carry it, without any assistance from gravity, through about 32 feet during the
second second. This is the final velocity of the body after one second. But during this second, the
body passes gradually from a state of rest through various increasing degrees of speed, until it acquires
a velocity equal to 32 feet per second. Its average speed, therefore, during the whole first second will
be the arithmetical mean between its starting velocity, which is 0, and its final velocity, which is 32 feet
per second. This mean is 16 feet per second; consequently, the space actually fallen through during
this one second must be 16 feet. During the second second, the body starting with the velocity of 32
feet acquired during the first second, falls through 32 feet, and also through another 16 feet due to the
action of its weight during this one second only. At the end of the second second the final velocity is
twice that at the end of the first second; 80 that during the third second the body would move through
64 feet, if subject to no force, i e., if its weight had ceased to act; but as this force continues to act, and
would, during a second, move it through 16 feet, (if it had no velocity at starting,) the whole space
described during this second will be 80 feet, viz., 64 feet by its previously acquired velocity, and 16 by
that gradually added during this third second.
Hence, it appears that the time occupied in falling, and the final velocity, are proportional to each
other; and that an increase in one is necessarily attended by a proportional increase in the other. Now,
we have seen that the average velocity, during any fall, is exactly half the final velocity, for it is the
mean between the velocity at starting, viz. 0, and that final velocity hence, any increase in the time
of falling, is attended by a proportional increase in the average speed during the whole fall. But the
space fallen through is jointly proportional to the time occupied and the average velocity; consequently,
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when the time is increased in any proportion, (say doubled,) the body falls, not only twice as long, but
also twice as fast, and must therefore fall through four times the distance. So, also, if one body falls
three times as long as another, it also falls with three times the average speed, and consequently falls
altogether nine times the distance. The distance fallen must always be proportional to the square of
the time occupied.
We thus get an easy rule for determining the space through which a body has fallen, simply by
knowing the time occupied by the fall, and multiplying the square of this by the number of feet through
which a body falls in one second. The same rule will apply to any number of seconds, whole or fractional.
To show more clearly how this law is derived from the uniformity of the accelerating force, take the
length of any figure to represent the time of the whole fall, which divide into any convenient number of
parts; and make the breadth of the figure, at each of those divisions, represent the velocity at the cor-
responding instant of the fall. Then the area of the figure, or of any portion thereof, will represent the
distance fallen through during the corresponding part of the time for this distance is jointly propor-
tional to the time and the average velocity, just as the area of a figure is jointly proportional to its length
and its average breadth. Let us draw such a figure, then, in which the breadth at the commencement
is 0, and increases uniformly, i. e. by equal additions, for equal additions to the length. By observing
the relations between its breadths at different points, and also between the areas of the whole and
different portions of it, and the areas they would have if their breadth continued equal throughout their
length, we may learn all that has been stated above, by simply substituting time for length, velocity for
breadth, and distance fallen for area. The following is an example:-
A body falling freely during 5 seconds:
Starting with a velocity
0
Ft. Tot. Fall.
Falls during the 1st second
16
=
16
16
Acquiring a velocity of
32 feet per second.
Falls during the 2d second
32+
16
48
64
Acquiring a velocity of twice 32, or
64 feet per second.
Falls during the 3d second
32+
32+
16
=
80
144
Acquiring a velocity of 3 X 32 =
96 feet per second.
Falls during the 4th second
32+
32+
32+
16
112
256
Acquiring a velocity of 4 X 32 =
128 feet per second.
Falls during the 5th second
32+
32+
32+
32+
16
=
144
400
Acquiring a velocity of 5 X 32 =
160 feet per second.
These laws are not confined to the motion of falling, but apply equally to every uniformly acceler-
ated motion, i. e. every motion produced by an uniform force or pressure. In every such motion, the
velocities, at any different instants, are proportional to the times elapsed since the beginning of the mo-
tion; the average velocity is half the final velocity; the space described during successive equal inter-
vals are as the series of odd numbers, 1, 3, 5, 7, &c.; and the whole spaces described from the begin-
ning of the motion are as the squares of the times taken to describe them. But the numerical data
will be different in each case of such motion; that is to say, the velocity acquired in a given time, or
the time occupied in acquiring a given velocity, will vary in each case from the effects of fluid resist-
ance and friction.
To submit all the laws which have thus been expounded to the test of direct experiment, is the object
of Atwood's machine, which see, Fig. 3.
Uniformly retarded motion.-Whatever has been stated respecting uniformly accelerated motion,
will be found equally applicable to the converse case of uniformly retarded motion. As in the former
case the velocity increased by equal additions in equal times, so in this case it is reduced by equal
losses in equal times; and if the force be the same, the velocity lost in any unit of time (such as a
second) will be equal to that gained in a similar unit in the former case. Thus, when a body is pro-
jected or thrown directly upwards, and then left to the action of gravity, it rises during any second 32
feet less than during the previous second, until its velocity is reduced to 0, and then to a motion in the
contrary direction, when the same law continues unaltered, for the body gains (like any other falling
body) 32 feet of downward motion per second.
The composition of motions.-It is a physical law of great importance and simplicity, that the dyna-
mical effects of forces are proportional to their statical effects. The same force which balances another
force of twice the amount, will also, when unbalanced, produce twice as much motion; that is to say. it
will either (I.) impart to twice as much matter the same velocity in the same time; or (II.) it will im-
part to the same matter twice the velocity in the same time; or (III.) it will impart to the name matter
the same velocity in half the time. It must be distinctly understood that this is a physical fact, or law
of nature,-not a fact to be learnt by deduction, but by induction from experiments.
The doctrine of the parallelogram of forces is applicable to the composition of motion. Thus, sup-
pose the body x, as in Fig. 1752, to be acted on at once by three forces in the directions of the arrows
ABC; that A acting alone would in one unit of time (such as a second, or an hour) drive the body to
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a; that B acting alone (and being weaker than A) would in the same length of time drive the body no
further than b; and that C, in like manner, acting alone, would cause it in the same length of time to
reach c. Now, to find the effect of A and B united, complete the parallelogram x a db, and its further
angle d is the point to which the body will be sent by the joint action of both A and B, in the same
length of time that it would have occupied in reaching a by the action of A only, or in reaching b by
the action of B only. This will be true, whether the two forces act both in the same manner or in
different manners, however varied but in the latter case, although the body arrives at the point d just
as soon, yet it will travel thither by a different route. In order that it may move along the straight
line x d, it is necessary that the two forces act in the same manner; such, for example, as by an instan-
taneous impulse, which will cause a uniform motion; or both may act continuously and uniformly, so
as to produce a uniformly accelerated motion, (like that of falling bodies;) or both forces may act with
a continually varying intensity, both increasing or diminishing at the same rate, and the motion will
still be rectilinear. But if one force be instantaneous and the other continuous, or one uniformly con-
tinued and the other varying in intensity, or both varying by different laws, 80 as not to preserve con-
stantly the same ratio to each other, then the path of the body will be a curve, still, however, conducting
it eventually to the point d, in the same time that the force A would have taken to send it to a, or B to b.
But suppose the third force C to act on the body x, and to be capable of carrying it to c in the same
time that A and B jointly would carry it to d. We have only to complete the parallelogram x d e c, to
find that by the combined action of all three forces the body will be sent in the same unit of time to e.
It is another remarkable consequence of this law, that whether we regard the directions of the three
forces as being all in one plane, or in different planes, the law is equally true.
This most important law as regards motions, may therefore be simply expressed in the following
terms :-that by any number of forces acting together for a given length of time, a body is brought to
the same place as if each of the forces, or one equal and parallel to it, had acted on the body separately
and successively for an equal length of time.
1757.
b
k
l
a
Let us now consider the effect of the composition of a uniform with a uniformly accelerated mo-
tion, the two being in different but not opposite directions, as in the case of projectiles, i. e. bodies
thrown horizontally, or obliquely. To simplify the questions, let us suppose them subject to no other
force than gravity, which continually deflects them out of the straight line which they would otherwise
describe, and which is called the line of projection. Now it matters not whether this line be horizontal,
inclining upwards, or inclining downwards, it will constantly be found that the vertical depth of the pro-
jectile below this line at any moment, is equal to the depth which it would have fallen during the time
which has elapsed since its projection. Thus, if a cannon-ball be shot from A in the direction A b, Fig. 1757,
and its original velocity be such as would carry it through the space A a during one second, then, if not
subject to gravity, it would proceed in a straight line and arrive at a in one second, at b in two seconds,
and 80 on. But gravity alone would cause it during the first second to fall 16 feet, (say from A to G.)
By completing the parallelogram A a Gg, then. we see that after one second the body will have arrived
at g, exactly as if it had first been carried by the projectile force during one second to a, and then fallen
during one second to g. In the same way, during the next second, the ball moves in the direction of
projection through the space a b, or g h, and in the direction of gravity through h 2 = 3 times 16 feet.
In the third second it advances as much as before, viz. 2 i, and falls 5 times 16 feet, bringing it to the
point 3. In the fourth and fifth seconds it advances in the direction 3 k, or 4 l, as much as in the first
second, but falls 7 times and 9 times as much, thus arriving at the points 4 and 5. Now it results from
this, that the points A, g, 2, 3, 4, 5, are necessarily situated on a curved line of that kind called a para-
bola, and if the place of the ball at any other moments (however numerous) be found, all these points
will likewise fall on the same curve.
The distance from A, at which the ball again crosses the horizontal line A 5, is called the horizontal
range. This will be the greatest possible, with a given velocity of projection, when the body is pro-
jected at an angle of 45° with the horizon. In this case the greatest height attained is just one-fourth
of the range. So that. as the time of flight is twice the time of falling that height, (or the exact time of
falling four times that height,) the ball arrives at its destination in the same time as if it had fallen a
like distance vertically by the action of gravity. Hence the range (in feet) is 16 times the square of
the number of seconds in the flight. It is also remarkable that the range will be diminished equally by
equal deviations from this angle, whether above or below it. Thus a mortar will (with the same charge)
carry to the same distance, on a level plain, when it is inclined 40° as when inclined 50°; or the same
at 10° as at 80°.
We have hitherto regarded gravity as a parallel force. But if the range of a projectile amounted to
some miles, 80 as to bear a measurable ratio to the earth's radius, it would be necessary, in finding its
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FORGE.
path very exactly, to regard it as a central force, by making the lines A G, a g, b2, i 3, k 4, 1 5, no longer
parallel, but such would, if continued, meet at the earth's centre.
The effect of this change is to convert the parabola into one extremity of a very long and narrow
ellipse, whose other extremity passes round the earth's centre, and has its focus at that centre. Such,
indeed, is the curve described by every projectile.
It is in this manner, then, that the moon revolves in an ellipse of small eccentricity, of which one focus
is occupied by the earth's centre. Her deflection from the straight line is due to a force exactly with
that which deflects a projectile; which force varies in intensity inversely as the square of her distance
from the earth's centre varies. Now, if we calculate in this manner her deflection or fall, supposing her
situated at our own distance from the earth's centre, we shall find it would be exactly 16 feet in a
second, 64 feet in two seconds, &c., &c., like that of our projectiles or falling bodies.
The observance of exactly the same laws in the motions of the satellites of the great planets, shows
that a force of the same kind is exerted towards their centres. Moreover, it has been established by
the joint labors of the two Herschels, that the same force regulates the motions of the immeasurably
distant double stars.
It appears, then, that attraction or gravity is a universal property common to all matter, every par-
ticle in the universe attracting every other particle; and there is no irregularity in the motions of the
bodies of the solar system, no deviations appreciable by the most delicate astronomical observations,
which has not been explained, and its period and amount accurately calculated on the principles of uni-
versal gravitation, according to the laws discovered by Kepler.
Central force.-The tendency which bodies in motion have to recede from its centre is called the
centrifugal force: the tendency to approach the centre of motion, is called the centripetal.
The central force of a body describing a circle with a uniform velocity is directly proportional to
the square of the velocity, and inversely as the radius of the circle. The doctrine of central forces has
its practical application in astronomy; the force by which the planets describe their orbits is a central
force, directed to the sun as a centre; and the forces by which the planetary motions are sustained,
vary inversely as the squares of the distances of the planet from that body.
In the case of fly-wheels, the succeeding rules will be found sufficient:
(A.)
velocity X weight
=
centrifugal
force.
radius X 32
(B.) Divide the velocity by 401, square the quotient, and divide by the diameter: this last quotient
multiplied by the weight, will give the centrifugal force.
(C.) Number of revolutions per minute X diameter
X
weight
=
the
5870
centrifugal
force.
(D.) velocity 2 X radius.
centrifugal force X
(E.) radius X centrifugal velocity force X 32 = weight.
(F.)
radius X centrifugal force X 32
= the velocity.
weight
The following examples will illustrate the application of these rules.
What is the centrifugal force of the rim of a fly-wheel moving with a velocity of 321 feet in a second,
and whose diameter is 20 feet.
(By
B.)
4:01 321 = 8.02 then 20 = 3-216, which multiplied by the weight of the rim, will give the
8-02"
centrifugal force.
A grindstone makes 120 revolutions in the minute, the radius of the circle of its motion being 2 feet,
and its weight 6 pounds.
(By
C.)
120² X 4
57600
5870 X 6 = 5870 X 6 = 981 X 6 = 58.86 = the centrifugal force.
A fly-wheel makes 65 revolutions per minute, its diameter being 12 feet, and the weight of the rim
one-ton, the weight of the entire fly being 11 tons, the circle of gyration is 5.5 feet from the axis, the
wheel consisting of two halves joined by bolts capable of resisting a pressure of 4 tons, wherefore,
12
X
3.1416
X
65
= 40.84 = velocity in feet per second.
60
And
(by
A.)
40.84'
X
X 6 = 8688 tons, the centrifugal force.
1
32
And (by F.)
32
X
4
X
5.5
X
1408
=
30-638,
and
since
2
X
55
X
3.1416
=
345576
=
1.5
1.5
the circle of gyration, therefore, 345576 638 X 60 = 59.197, the number of revolutions per minute, which
would cause the fly to burst asunder.
FORGE. The workshop in which iron is hammered and shaped by the aid of heat. The term is
generally applied to the places in which these operations are carried on upon the comparatively small
scale; the great workshops in which iron is made malleable for general purposes being called a
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shingling mill. A common forge consists of the hearth or fireplace, which is merely a cavity in
masonry or brickwork well lined with fine clay or brick, upon which the ignited fuel is placed, and upon
the back or side of which a powerful blast of air is driven in through the nozzle of a double-blasted
bellows, which, in a common forge, is generally worked by a hand lever. Forges are sometimes con-
structed 80 as to be portable, when the bellows is most conveniently placed under the hearth; these are
used in ships, and for various jobs on railways, &c.
FORGING-Iron and steel. The heaviest works are generally heated in air furnaces of various
descriptions, some of which resemble, but greatly exceed in size, those employed in the works where
iron is manufactured, and in which the process of forging may be truly considered to commence with
the first blow given upon the ball, as it leaves the puddling furnace for being converted into a bloom.
The paddle-shafts of the largest steamships are wrought by successive additions at the one end, as
follows: A slab of iron, technically called a use," is welded on one side close to the end, and when
drawn down to the common thickness, the additional matter becomes thrown into the length; the next
use is then placed on the adjoining side of the as yet square shaft, and also drawn into the length, and
so on until the full measure is attained.
First, the heat" has a long iron rod attached to it in continuation of its axis, to serve as a porter"
or guide rod the mass is suspended under a traversing crane at that point where it is nearly equipoised;
the crane not only serves to swing it round from the fire to the hammer, but the traverse motion also
moves the work endways upon the anvil, and small changes of elevation are sometimes effected by a
screw adjustment in the suspending chain. The circular form is obtained by shifting the work round
upon its axis by means of a cross level fixed upon the porter, and moved by one or two men, so as to
expose each part of the circumference to the action of the helve; this is readily done as the crane ter-
minates in a pulley, around which an endless band of chain is placed, and the work lies within the
chain, which shifts round when the work is turned upon the anvil.
A similar mode of work is adopted on a smaller scale for many of the spindles, shafts, and other
parts of ordinary mechanism, which are forged under the great hammer, often of several bars piled
together and fagoted; a suitable term, as they are frequently made of a round bar in the centre, and
a group of bars of angular section, called mitre iron, around the saine, which are temporarily wedged
within a hoop, somewhat after the manner of a fagot of wood. Such works are also made of scrap-iron.
A number of these fragments are enveloped in an old piece of sheet-iron, and held together by a
hoop; the mass is raised to the welding heat in a blast or air furnace, and the whole is consolidated
and drawn down under the tilt-hammer; one long bar that serves as the porter being welded on by the
first blow. The mingling of the fibres in the scrap-iron is considered highly favorable to the strength
of the bar produced. The scrap-iron is sometimes twisted during the process of manufacture, to lay all
the filaments like a rope, and prevent the formation of spills, or the longitudinal dirty seams found on
the surface of inferior iron.
The long furnaces are particularly well suited to straight works and bars, but when the objects get
shorter and of more complex figures, the open fire or ordinary smith's hearth is employed. This, when
of the largest kind, is a trough or pit of brickwork about six feet square, elevated only about six inches
from the ground; the one side of the hearth is extended into a vertical wall leading to the chimney, the
lower end of which terminates in a hood usually of stout plate iron, which serves to collect the smoke
from the fire. The black wall of the forge is fitted with a large cast-iron plate, or a back, in the centre
of which is a very thick projecting nozzle also of iron, perforated for admitting the wind used to urge
the fire; the aperture is called the tuyere.
The blast is sometimes supplied from ordinary bellows of various forms; at other times by enormous
air-pumps, which lead into a cylinder or regulator, the piston of which is loaded with weights, so as to
force the air through pipes all over the smithy, and every fire has a valve to regulate its individual
blast; but the more modern and general plan is the revolving fan, also worked by the engine, the blast
from which is similarly distributed.
In some cases the cast-iron forge back is made hollow, that a stream of water may circulate through
it from a small cistern; the water-back is thereby prevented from becoming 80 hot as the others, and its
durability is much increased. In other cases the air, in its passage from the blowing apparatus, flows
through chambers in the back plate 80 as to become heated in its progress, and thus to urge the fire
with hot blast, which is by many considered to effect a very great economy in the fuel.
Some heavy works of rather complex form, such as anchors, are most conveniently managed by hand
forging; many of these require two gangs of men with heavy sledge hammers, each consisting of six
to twelve men, who relieve each other at short intervals, as the work is exceedingly laborious.
The square shanks of anchors are partly forged under a vertical hammer of very simple construction,
called a 'monkey." It consists of a long iron bar running very loosely through an eye or aperture
several feet above the anvil, and terminating at foot in a mass of iron, or the ram. The hammer is ele-
vated by means of a chain, attached to the rod and also to a drum overhead, which is put into geer with
the engine, and suddenly released by a simple contrivance, when the hammer has reached the height of
from two to five feet, according to circumstances. The ram is made to fall upon any precise spot within
a horizontal range of some twenty inches from the central position by two slight gye-rods, hooked to
the ram and placed at right angles. This contrivance is far more effective than the blows of the sledge
hammers, and although now but little used is perhaps more suitable to such purposes than the helve or
lift hammer, which always ascends to one height, and falls upon one fixed spot.
Nasmyth's steam hammer is now almost entirely used in forging anchors: it has very much
shortened the process, and makes more perfect work.
The square shank of the anchor, and works of the same section, are readily shifted the exact quarter
circle, as the sling-chain is made with flat links, each a trifle longer than the side of the square of the
work, which therefore bears quite flat upon one link, and when twisted it shifts the chain the space of a
link, and rests as before.
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FORGING.
Many implements and tools, such as shovels, spades, mattocks, and cleavers, are partly forged under
the tilt-hammer the preparatory processes, called moulding, which include the insertion of the steel,
are done by ordinary hand forging. The objects are then spread out under the broad face of the tilt-
hammer, the workman in such cases being sometimes seated on a chair suspended from the ceiling. and
by paddling about with his feet, he places himself with great dexterity in front or on either side of the
anvil with the progressive changes of the work; the concluding processes are mostly done by hand
with the usual tools. A similar arrangement is also adopted in tilting small sized steel
With the reduction of size in the objects to be forged, the number of hands is also lessened, and the
crane required for heavy work is abandoned for a chain or sling from the ceiling; but for the majority
of purposes two men only are required, when the work is said to be two-handed.
As the works to be forged become smaller, the hearth is gradually lessened in size, and more elevated,
so as to stand about two and a half feet from the ground it is now built hollow, with an arch beneath
serving as the ash-pit. . The single hearths are made about a yard square, and those forges which have
two fires under the same hood, measure about two yards by one; a double trough to contain water in
the one compartment and coals in the other, is usually added, and the ordinary double bellows are used.
Figs. 1765 and 1758 are called flat-bit tongs these are either made to fit very close as in Fig. 1758,
for thin works, or to stand more open as in Fig. 1765, for thicker bars, but always parallel: and a ring
or coupler, is put upon the handles or reins, to maintain the grip upon the work. Others of the same
general form are made with hollow half-round bits; but it is much better they should be angular, like
the ends of Fig. 1759, as then they serve equally well for round bars, or for square bars held upon their
opposite angles. Tongs that are made long, and swelled open behind, as in Fig. 1759, are very
excellent for general purposes, and also serve for bolts and similar objects, with the heads placed
inward. The pincer tongs, Fig. 1760, are also applied to similar uses, and serve for shorter bolts.
1759.
1762.
1760.
1764.
1763.
1758.
1761.
1765.
Flg. 1761 represents tongs much used amongst the cutlers; they are called crook-bit tongs; their
jaws overhang the side, so as to allow the bar of iron or steel to pass down beside the rivet, and the
nib at the end prevents the rod from being displaced by the jar of hammering. Fig. 1762. or the ham-
mer tongs, are used for managing works punched with holes, such as hammers and hatchets; as the
pins enter the holes and maintain the grasp.
Fig. 1763, or hoop tongs, are very much used by ship-smiths, for grasping hoops and rings, which may
be then worked either on the edge, when laid flat on the anvil, or on the side, when upon the beak-iron;
and lastly, Fig. 1764 represents the smith's pliers, or light tongs, used for picking up little pieces of iron,
or small tools and punches.
In addition to the hearth, anvil, and tongs, the smithy contains a number of chisels, punches, and
swages or striking tools, called also top and bottom tools, of a variety of suitable forms and generally
in pairs; these may be considered as reduced copies of the grooves turned in the rollers, and occasion-
ally made on the faces of the tilt-hammers of the iron-works for the production of square, flat, round,
T-fonn iron, angle iron, and railway bars, as referred to. In fitting the hazel-rods to the top tools, the
rods are alternately wetted in the middle of their length, and warmed over the fire to soften them; that
portion is then twisted like a rope, and the rod is wound once round the head of the tool, and retained
by an iron ferrule or couples; a rigid iron handle would jar the hand.
When these tools are used for large works, a square plate of sheet-iron, with a hole punched in the
middle of it, is put on the rod towards the tool, to shield the hand of the workman from the heat; and
it not unfrequently happens with such large works that the rod catches fire, and the tool is then dipped
at short intervals in the slake trough to extinguish it.
The smith who works without any helpmate is much more circumscribed as to tools, and he is from
necessity compelled to abandon all those used in pairs, unless the upper tools have some mechanical
guide to support and direct them. In addition to the anvil he only uses the fixed cutter and heading
tools; he may occasionally support the end of the tongs in a hook attached to his apron-string, or sus-
pended from his neck, whilst he applies a hand-chisel, a punch, or a name-mark in the left hand, and
strikes with the hammer held in the right.
Attempts to work small tilt-hammers with the foot have been found generally ineffective, as the
attention of the individual is too much subdivided in managing the whole, neither is his strength
sufficient for a continued exertion at such work; but the " Oliver" is one of the best tools of this class.
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A portable forge of suitable dimensions for single hand-forging, and made entirely of iron, is repre-
sented in Fig. 1766. The bellows are placed beneath the hearth and worked by a treadle.
This forge is also occasionally fitted with a furnace for melting small quantities of metal, and with
various apparatus for other applications of heat, such as soldering, either with a small charcoal fire,
or a lamp and blow-pipe, which are likewise urged with the bellows. These applications, and also that
of hardening and tempering tools, are much facilitated by the bellows being worked with the foot, as it
leaves both hands at liberty for the management either of the work or fire.
The forge represented is sufficiently
powerful for a moderate share of those
works which require the use of the sledge-
1766.
hammer.
The ordinary fuel for the smith's forge
is coal, and the kinds to be preferred are
such as are dense and free from metallic
matters, as these are generally accom-
panied with sulphur, which is highly
detrimental.
In forging, the iron or steel is in
almost every case beated to a greater
or less degree, to make it softer and
more malleable by lessening its cohe-
sion; the softening goes on increasing
with the accession of temperature, until
it arrives at a point beyond that which
can be usefully employed, or at which
the material, whether iron or steel, falls
in pieces under the blows of the ham-
mer, but which degree is very different
with various materials, and even with
varieties bearing the same name.
Pure iron will bear almost unlimited
degree of heat the hot-short iron bears
much less, and is in fact very brittle
when heated other kinds are interme-
diate. Of steel, the shear-steel will gen-
erally bear the highest temperature, the
blistered-steel the next, and the cast-
steel the least of all but all these
kinds, especially cast-steel, differ very
much according to the processes of man-
ufacture, as some cast-steel may be
readily welded, but it is then somewhat
less certain to barden perfectly.
The smith commonly speaks of five
degrees of temperature, namely:
The black-red heat, just visible by daylight;
The low-red heat;
The bright-red heat, when the black scales may be seen;
The white heat, when the scales are scarcely visible;
The welding heat, when the iron begins to burn with vivid sparks.
Steel requires on the whole very much more precaution as to the degree of heat than iron; the
temperature of cast-steel should not generally exceed a bright-red heat, that of blistered and shear-steel
that of a moderate white heat. Although steel cannot in consequence be 80 far softened in the fire as
iron, and is therefore always more dense and harder to forge, still from its superior cohesion it bears a
much greater amount of hard work under the hammer, when it is not over-heated or burned but the
smallest available temperature should be always employed with this material, as in fact with all others.
The cracks and defects in iron are generally very plainly shown by a difference in color at the parts
when they are heated to a dull red this method of trial is often had recourse to in examining the
soundness both of new and old forgings.
When a piece of forged work is required to be particularly sound, it is a common practice to subject
every part of the material in succession to a welding heat, and to work it well under the hammer, as a
repetition of the process of manufacture to ensure the perfection of the iron: this is technically called,
taking a heat over it; in fact, a heat is generally understood to imply the welding heat. For a two-
inch shaft of the soundest quality, two and a half inch iron would be selected, to allow for the reduc-
tion in the fire and the lathe; some also twist the iron before the hammering to prevent it from be-
coming " spilly."
The use of sand sprinkled upon the iron is to preserve it from absolute contact with the air, which
would cause it to waste away from the oxidation of its surface. and fall off in scales around the anvil.
If the sand is thrown on when the metal is only at the full red heat, it falls off without adhering but
when the white heat is approached, the sand begins to adhere to the iron; it next melts on its surface,
over which it then runs like fluid glass, and defends it from the air when this point has been rather
exceeded, so that the metal nevertheless begins to burn with vivid sparks and a hissing noise like
fireworks, the welding temperature is arrived at, and which should not be exceeded. The sparks are,
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FORGING.
however, considered a sign of a dirty fire or bad iron, as the purer the iron the less it is subject to
waste or oxidation in the course of work.
In welding two pieces of iron together, care must be taken that both arrive at the welding heat at
the same moment; it may be necessary to keep one of the pieces a little on one side of the most
intense part of the fire, (which is just opposite the blast,) should the one be in advance of the other.
In all cases a certain amount of time is essential; otherwise, if the fire be unnecessarily urged, the
outer case of the iron may be at the point of ignition before the centre has exceeded the red heat.
In welding iron to steel, the latter must be heated in a considerably less degree than the iron, the
welding heat of steel being lower from its greater fusibility but the process of welding will be sepa-
rately considered under a few of its most general applications, when the ordinary practice of forging
has been discussed, and to which we will now proceed.
The general practice of forging works from the bar of iron or steel, are for the most part included
in the three following modes; the first two occur in almost every case, and frequently all three to-
gether; namely,
By drawing-down, or reduction:
By jumping or upsetting, otherwise thickening and shortening:
By building-up, or welding.
To meet the variety of cases which occur, the smith has hammers in which the panes are made in
different ways, either at right angles to the handle, parallel with the same, or oblique.
In order to obtain the same results with more precision and effect, tools of the same characters, but
which are struck with the sledge-hammer, are also commonly used: those with flat faces are made
like hammers, and usually with similar handles, except that for the convenience of reversing them they
are not wedged in these are called set-hammers others which have very broad faces, are called flat-
ters; and the top tools with narrow round edges like the pane of the hammer, are called top-fullers;
they all have the ordinary hazel-rods.
When the sides of the object are required to be parallel, and it is to be reduced both in width and
thickness, the flat face of the hammer is made to fall parallel with the anvil, as represented in Fig.
1767; or oblique for producing taper pieces, as in Fig. 1768; and action and reaction being equal, the
lower face of the work receives the same absolute blow from the anvil as that applied above by the
hammer itself; it is not requisite, therefore, (for works of moderate dimensions,) to present every one
of the four sides to the hammer, but any two, at right angles to each other.
The smith must acquire the habit of feeling when the bar lies perfectly flat upon the anvil, by hold-
ing it slenderly, leaving it almost to rotate in his grasp, or in fact to place itself. Next he must cause
the hammer to fall flat upon the work.
It would be desirable practice to hammer a bar of cold iron, or still better, one of steel, as there
would be more leisure for observations; the indentations of the hammer could be easily noticed; and if
the work, especially steel, were held too tightly, or without resting fairly on the anvil, it would indicate
the error by additional noise and by jarring the wrist; whereas, when hot, the false blows or positions
would cause the work to get out of shape, without such monitorial indications.
1769
1767.
1768.
As to the best form of the hammer, there is much of habit and something of fancy. The ordinary
hand-hammer is represented in Figs. 1767 and 1768; but cutlers, and most tool makers, prefer the
hammer without a pane, or narrow edge, and with the handle quite at the top, the two forming almost
a right angle, or from that to about eighty degrees; and sometimes the head is bent like a portion of a
circle. Similar but much heavier hand-hammers, occasionally of the weight of 12 or 14 pounds,
are used by the spade-makers for planishing; but the work being thin and cold, the hammer rises
almost exclusively by the reaction, and requires little more than guidance. Again, the farriers prefer
for some parts of their work, a hammer the head of which is almost a sphere; it has two flat faces,
one rounded face for the inside of the shoe, and one very stunted pane at right angles to the handle,
used for drawing down the clip in front of the horse-shoe; in fact, nearly a small volume might be
written upon all the varieties of hammers.
Suppose it required to draw down six inches of the end of a square or rectangular bar of iron or
steel; the smith will place the bar across the anvil with perhaps four inches overhanging, and not
resting quite flat, but tilted up about a quarter or half an inch at the near side of the nnvil, as in Fig.
1768, but less in degree, and the hammer will be made to fall as there shown, except that it will be at
a very small angle with the anvil.
In smoothing off the work, the position of Fig. 1767 is assumed; the work is laid flat upon the
anvil, and the hammer is made to fall as nearly as possible horizontally; a series of blows are given
all along the work between every quarter turn, the hammer being directed upon one spot, and the work
drawn gradually beneath it.
In drawing down the tang or taper-point of a tool, the extreme end of the iron or steel is placed
a little beyond the edge of the anvil, as in Fig. 1768, by which means the risk of indenting the anvil
is entirely removed, and the small irregular piece in excess beyond the taper is not cut off until the
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FORGING.
689
tang is completed. Fig. 1769 shows the position of the chisel in cutting off the finished object from
the bar of which it formed a part; that is, the work is placed between the edge of the anvil and
that of the chisel immediately above the same; the two resemble in effect a pair of shears.
When it is required to make a set-off, it is done by placing the intended shoulder at the edge of the
anvil: the blows of the hammer will be effective only where opposed to the anvil, but the remainder
of the bar will retain its full size and sink down, as represented in Fig. 1770. Should it be necessary
1772.
1770.
1771.
0
to make a shoulder on both sides, a flat-ended set-hammer, struck by the sledge, is used for setting
down the upper shoulder, as in Fig. 1771, as the direct blows of the hammer could not be given with
so much precision. In each of these cases some precaution must be observed, as otherwise the tools,
although 80 much more blunt than the chisel, Fig. 1769, will resemble it in effect, and cripple or
weaken the work in the corner on this account the smith's tools are rarely quite sharp at the angles:
this mischief is almost removed when the round fullers, Fig. 1772, are used for reducing the principal
bulk, and the sharper tools are only employed for trimming the angles with moderate blows.
When the iron is to be set down, and also
spread laterally, as in Fig. 1773, it is first nicked
a
with a round fuller as upon the dotted line at a,
1773.
and the piece at the end is spread by the same
tool, upon the short lines of the object, or paral-
lel with the length of the bar: the first notch
greatly assists in keeping a good shoulder at the
bottom of the part set down, and the lines are
supposed to represent the rough indentations of the round fuller before the work is trimmed up.
There is often considerable choice of method in forging, and the skilful workman selects that method
of proceeding which will produce the result with the least portion of manual labor.
Figs. 1775, 1776, and 1777, explain these processes of making an ordinary screw-bolt; the latter is
a single tool, but the heading-tool, Fig. 1778, with several holes, is also used.
In upsetting the end of the work, if more convenient, it may be held horizontally across the anvil,
and struck on the heated extremity with the hand-hammer; or it can be jumped forcibly upon the
anvil, when its own weight will supply the required momentum. If too considerable a portion of the
work is heated, it will either bend, or it will swell
generally; and therefore to limit the enlargement
to the required spot, should the heat be too long,
1774.
1777.
1781.
the neighboring part is partially cooled by immer-
1778.
sing it in the water-trough, as near to the heat as
admissible.
1776.
A bolt may be made by building up or weld-
1775.
ing :-An eye is first made at the end of a small
rod of square or flat iron by bending it round the
beak-iron, as in Fig. 1779, it is placed around the
1780.
rod of round iron, and the curled end is cut off with
the chisel, as in Fig. 1780, enough iron being left in
the ring, which is afterwards welded to the rod to
form the head of the bolt, by a few quick light
blows given at the proper heat; the bolt is then
1779.
completed by any of the tools already described
that may be preferred. A swage at the angle of
sixty degrees, Fig. 1781, will be found very couve-
nient in forming hexagonal heads, as the horizontal
blow of the hammer completes the equilateral tri-
angle, and two positions operate on every side of the hexagon; Fig. 1781 is essential likewise in
forging triangular files and rods.
For the parts of mechanism in which a considerable length of two different sections or magnitudes
of iron are required, the method by drawing down from the large size would be too expensive; the
method by upsetting would be impracticable; and therefore a more judicious use is made of the iron
store, and the object is made in two parts, of bars of the exact sections respectively. The larger bar
is reduced to the size of the smaller, generally upon the beak-iron with top fullers, and with a gradual
transition or taper extending some few inches, as represented in Fig. 1782; the two pieces are scarfed
or prepared for welding.
Fig. 1782 is also intended to explain two other proceedings very commonly required in forging.
Bars are bent down at right angles as for the short end or corking of the piece, Fig. 1782, by laying
the work on the anvil, and holding it down with the sledge-hammer, as in Fig. 1783; the end is then
bent with the hand-hammer, and trimmed square over the edge of the anvil; or when more precision
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is wanted, the work is screwed fast in the tail-vice, which is one of the tools of every smith's shop,
and it is bent over the jaws of the vice. When the external angle, as well as the internal, is required
to be sharp and square, the work is reduced with the fuller from a larger bar to the form of Fig. 1784,
to compensate for the great extension in length that occurs at the outer part, or heel of the bend, of
which the inner angle forms as it were the centre.
The holes in Fig. 1782 for the cross-bolts are made with a rod-punch, which is driven a little more
than half way through from the one side whilst the work lies upon the anvil, 80 that when turned
over, the cooling effect of the punch may serve to show the place where the tool must be again ap-
plied for the completion of the hole; the little bit or burr is then driven out, either through the square
hole in the anvil that is intended for the bottom tools, or else upon the holster, Fig. 1785, a tool faced
with steel, and having an aperture of the same form and dimensions as the face of the punch.
1783.
1782.
MM
The
1785.
1786.
1787.
1788.
1784.
1789.
Fig. 1788 shows the ordinary mode of making the square nuts for bolts. A flat bar is first nicked on
the sides with the chisel, then punched, and the rough nuts, if small, are separated and strung upon the
end of the poker, (a slight round rod bent up at the end,) for the convenience of managing them in the
fire, from which they are removed one at a time when hot, and finished on the triblet, Fig. 1789, which
serves both as a handle, and also as the means of perfecting the holes.
For making hexagon nuts, the flat bar is nicked on both edges with a narrow round fuller; this gives
A nearer approach to the hexagon: the nuts are then flattened on the face, punched, and dressed on
the triblet within the angular swage, Fig. 1781, before adverted to. Thick circular collars are made
precisely in the same way, with the exception that they are finished externally with the hammer, or
between top and bottom rounding tools of corresponding diameter.
It is usual in punching holes through thick pieces, to throw a little coal-dust into the hole when it is
partly made, to prevent the punch sticking in so fast as it otherwise would the punch generally gets
red-hot in the process, and requires to be immediately cooled on removal from the hole.
In making a socket, or a very deep hole in the one end of a bar, some difficulty is experienced in
getting the hole in the axis of the bar, and in avoiding to burst open the iron; such holes are produced
differently, by sinking the hole as a groove in the centre of a flat bar by means of a fuller; the piece
is cut nearly through from the opposite side, folded together lengthways, and welded. The hole thus
formed will only require to be perfected by the introduction of an appropriate punch, and to be worked
on the outside, with those tools required for dressing off its exterior surface, whilst the punch remains
in the hole to prevent its sides from being squeezed in this method is very good.
For punching square holes, square punches and bolsters are used, and Fig. 1786, the split bolster, is
employed for cutting out long rectangular holes or mortises, which are often done at two or more cuts
with an oblong punch.
When a thick lump is wanted at the end of a bar, it is often made by cutting the iron nearly through
and doubling it backwards and forwards, as in Fig. 1787; the whole is then welded into a solid mass
as the preparatory step.
1790.
1791.
A piece with three tails, such as Fig. 1790, is made from a large square bar an elliptical hole is first
punched through the bar, and the remainder is split with a chisel, as in Fig. 1791, the work at the
time being laid upon a soft iron cutting plate in order to shield the chisel from being driven against the
hardened steel face of the anvil; the end is afterwards opened into a fork, and moulded into shape over
the beak-iron, as indicated by the dotted lines.
Such a piece as Fig. 1790, if of large dimensions, would be made in two separate parts, and welded
through the central line or axis.
Should it happen the two arms are not quite parallel, an error that could scarcely be corrected by
the hammer alone, the work would be fixed in the vice with the two tails upwards, and the one or
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other of these would be twisted to its true position by a hook wrench or set, made like the three sides
of a square, but the one very long to serve as a lever; it is applied exactly in the manner of a key,
spanner, or screw-wrench, in turning round a bolt or screw.
Some bent objects, such as cranks and straps, are made from bar-iron, bent over specific moulds,
which are sometimes made in pairs like dies, and pressed together by screw contrivances. When the
moulds are single, the work is often retained in contact with the same, at some appropriate part, by
means of straps and wedges; whilst the work is bent to the form of the mould by top tools of suitable
kinds.
Objects of more nearly rectilinear form are cut out of large plates and bars of iron with chisels; for
example, the cranks of locomotive engines are faggoted up of several bars or uses laid together, and
pared to the shape they are sometimes forged in two separate parts, and welded between the cranks;
at other times they are forged out of one parallel mass, and afterwards twisted with a hook-wrench, in
the neck between the cranks, to place the latter at right angles. The notches are sometimes cut out
on the anvil whilst the work is red-hot; or otherwise by machinery when in the cold state.
A very different method of making rectangular cranks and similar works is also recommended, by
bending one or more straight bars of iron to the form; the angles, which are at first rounded, are per-
fected by welding on outer caps. In this case the fibre runs round the figure, whereas when the gap is
cut out, a large proportion of the fibres are cut into short lengths, and therefore a greater bulk must be
allowed for equal strength: this method is however seldom used.
All kinds of levers, arms, brackets, and frames, are made after these several methods, partly by
bending and welding, and partly by cutting and punching out; and few branches of industry present a
greater variety in the choice of methods, and which call the judgment of the smith continually into re-
quisition.
There are several ways of accomplishing the operation of welding, and which bear some little analogy
to the joints employed in carpentry; more particularly that called scarfing, used in the construction of
long beams and girders by joining two shorter pieces together endways, with sloping joints, which in
carpentry are interlaced or mortised together in various ways, and then secured by iron strape or bolts.
In smith's work likewise, the joinings are called scarfs, but from the adhesive nature of the iron when
at a suitable temperature, the accessories called for in carpentry, such as glue, bolts, straps, and pins,
are no longer wanted.
The scarfs required for the shut, are made by first upsetting or thickening the iron by blows upon its
extremity, to prepare it for the loss it will sustain from scaling off, both in the fire and upon the anvil,
and also in the subsequent working upon the joint. It is next rudely tapered off to the form of a flight
of steps, as shown in Figs. 1792 and 1793, and the sides are slightly bevelled or pointed, as in Fig.
1793, the proportion being somewhat exceeded to render the forms more apparent.
1792.
1796.
1793.
b
a
c
1794.
1795.
The two extremities are next heated to the point of ignition; and when this is approached, a little
sand is strewed upon each part, which fuses and spreads something like a varnish, and partially
defends them from the air the heat is proper when, notwithstanding the sand, the iron begins to burn
away with vivid sparks. The two men then take each one piece, strike them forcibly across the anvil to
remove any loose cinders, place them in their true positions, exactly as in Fig. 1792, and two or three
blows of the small hammer of the principal or fireman stick them together; the assistant then quickly
joins in with the aledge-hammer, and the smoothing off and completion of the work are soon accom-
plished.
It is of course necessary to perform the work with rapidity, and literally to strike whilst the iron is
hot the smith afterwards jumps the end of the rod upon the anvil, or strikes it endways with the
hammer this proves the soundness of the joint, but it is mostly done to enlarge the part, should it
during the process have become accidentally reduced below the general size. The sand appears to be
quite essential to the process of welding, as although the heat might be arrived at without its agency,
the surfaces of the metal would become foul and covered with oxide when unprotected from the air; at
all events common experience shows that it is always required. The scarf joint, shown in Figs. 1792
and 1793, is commonly used for all straight bars, whether flat, square, or round, when of medium size.
In very heavy works the welding is principally accomplished within the fire: the two parts are pre-
viously prepared either to the form of the tongue or split joint, Fig. 1794, or to that of the butt joint,
Fig. 1795, and placed in their relative positions in a large hollow fire. When the two parts are at the
proper heat, they are jumped together endways, which is greatly facilitated by their suspension from
the crane, and they are afterwards struck on the ends with sledge-hammers, a heavy mass being in
some cases held against the opposite extremity to sustain the blows; the heat is kept up, and the work
is ultimately withdrawn from the fire, and finished upon the anvil
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The butt joint, Fig. 1794, is materially strengthened, when, as it is usually the case for the paddle
shafts of steam-vessels and similar works, the joint whilst still large is notched in on three or four sides,
and pieces called stick-in pieces, dowels, or charlins, one of which is represented by the dotted lines, are
prepared at another fire, and laid in the notches; the whole, when raised to the welding heat, is well
worked together and reduced to the intended size; this mingles all the parts in a very substantial man-
ner. For the majority of works, however, the scarf joint, Fig. 1792, is used, but the stick-in pieces are
also occasionally employed, especially when any accidental deficiency of iron is to be feared.
When two bars are required to form a T joint, the transverse piece is thinned down as at a, in Fig.
1796; for an angle or corner the form of b may be adopted; but c, in which each part is cut off ob-
liquely, is to be preferred. The pieces a, b, c, are represented upside down, in order that the ridges set
down on their lower surfaces may be seen. In most cases when two separate bars are to be joined,
whatever the nature of the joint, the metal should be first upset, and then set down in ridges on the
edge of the anvil, or with a set-hammer, as the plain chamfered or sloping surfaces are apt to slide
asunder when struck with the hammer, and prevent the union. When a T joint is made of square or
thick iron, the one piece is upset, and moulded with the fuller much in the form of the letter; it is then
welded against the flat side of the bar such works are sometimes welded with dowel or tenon joints,
but all the varieties of method cannot be noticed.
Fig. 1787 may be taken as an example, in which the parts have no disposition to separate; in this and
similar cases the smith often leaves the parts slightly open, in order that the very last process before
welding may be the striking the whole edgeways upon the anvil, to drive out any loose scales, cinders,
or sand, situated between the joints.
In works that have accidentally broken in the welded part, the fracture will be frequently seen to
have arisen from some dirty matter having been allowed to remain between them, on which account,
shuts or welded joints extending over a large surface are often less secure than those of smaller area,
from the greater risk of their becoming foul In fact, throwing a little small coal between the contiguous
surfaces of work not intended to be united, is a common and sometimes a highly essential precaution to
prevent them from becoming welded.
The conical sockets of socket chisels, garden spuds, and a variety of agricultural implements, are
formed out of a bar of flat iron, which is spread out sideways or to an angle, with the pane of the
hammer, and then bent within a semicircular bottom tool also, by the pane of the hammer, to the form
of Fig. 1797 after which the sockets are still more curled up by blows on the edges and are per-
fected upon a taper-pointed mandrel, so that the two edges slightly overlap at the mouth of the socket,
and meet pretty uniformly elsewhere, as in Fig. 1798; and lastly, about an inch or more at the end is
welded. Sometimes the welding is continued throughout the length, but more commonly only a small
portion of the extremity is thus joined, and the remainder of the edges are drawn together with the
pane of the hammer.
1797.
1798.
In making wrought-iron hinges, two short slits are cut lengthways and nearly through the bar, to-
wards its extremity; the iron is then folded round a mandrel, set down close in the corner, and the two
ends are welded together. To complete the hinge, it only remains to cut away transversely, either the
central piece or the two external pieces to form the knuckles, and the addition of the pin or pivot fin-
ishes the work.
Musket-barrels, when made entirely by hand, were forged in the form of long strips about a yard
long and_ four inches wide, but taper both in length and width, which were bent round a cylindrical
mandrel until their edges slightly overlapped; they were then welded at three or four heats, by intro-
ducing the mandrel within them instantly on their removal from the fire at the proper heat, in order to
prevent the sides of the tube from being pressed together by the blows of the hammer.
They have been subsequently, and are now almost universally welded by machinery at one heat, and
whilst of the length of only one foot, as on removal from the fire the mandrel is quickly introduced,
and the two are passed through a pair of grooved rollers: they are afterwards extended to the full
length by similar means, but at a lower temperature, 80 that the iron is not 80 much injured as when
thrice heated to the welding point.
The twisted barrels are made out of long ribands of iron wound spirally around a mandrel, and
welded on their edges by jumping them upon the ground, or rather on an anvil embedded therein.
The plain stub barrels are made in this manner, from iron manufactured from a bundle of stub-nails,
welded together and drawn out into ribands to ensure the possession of a material most thoroughly and
intimately worked. The Damascus barrels are made from a mixture of stub-nails and clippings of steel
in given proportions, puddled together, made into a bloom, and subsequently passed through all the
stages of the manufacture of iron already explained, to obtain an iron that shall be of unequal quality
and hardness, and therefore display different colors and markings when oxidized or browned.
Other twisted barrels are made in the like manner, except that the bars to form the ribands are
twisted whilst red-hot like ropes, some to the right, others to the left, and which are sometimes again
laminated together for greater diversity they are subsequently again drawn into the ribands and wound
upon the mandrel, and frequently two or three differently prepared pieces are placed side by side to
form the complex and ornamental figures for the barrels of fowling-pieces, described as stub-twist, wire-
troist, Damascus twist," &c., which processes are minutely explained and figured by Greener, on
Gunnery."
All these matters are also explained in Wilkinson's Engines of War," which likewise treats of one
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method amongst others of the formation of the Damascus gun-barrels, by arranging twenty-five thin
bars of iron and mild steel in alternate layers, welding the whole together, drawing it down small,
twisting it like a rope, and again welding three such ropes, for the formation of the riband, which is then
spirally twisted to form a barrel, that exhibits, when finished and acted upon by acids, a diversified
laminated structure, resembling when properly managed an ostrich feather.
To turn from these engines of destruction to a modification of one of them to a happier purpose.
When the illumination by gas was first introduced in the large way, by Aaron Manby, Esq., then of the
Horsley Iron Works, the old musket-barrels, laid by in quiet retirement from the fatigues of the last
war, were employed for the conveyance of gas; and by a curious coincidence, various iron foundries
desisted in a great measure from the manufacture of iron ordnance, and took up the peaceful employ-
ment of casting pipes for gas and water.
The breech ends of the musket-barrels were broached and tapped, and the muzzles were screwed
externally, to connect the two without detached sockets. From the rapid increase of gas illumination,
the old gun-barrels soon became scarce, and new tubes with detached sockets, made by the old barrel-
forgers, were first resorted to. This led to a series of valuable contrivances for the manufacture of the
wrought-iron tubes, commencing with Russel's patent, in 1824, under which the tubes were first bent
up by hand-hammers and swages, to bring the edges near together; and they were welded between
semicircular swages, fixed respectively in the anvil, and the face of a small tilt-hammer worked by
machinery, by a series of blows along the tube, either with or without a mandrel. The tube was com-
pleted on being passed between rollers with half-round grooves, which forced it over a conical or egg-
shaped piece at the end of a long bar, to perfect the interior surface.
Various steps of improvement have been since made; for instance, the skelps were bent at two
squeezes, first to the semi-cylindrical, and then to the tubular form, (preparatory to welding,) between
a swage-tool five feet long, worked by machinery. The whole process was afterwards carried on by
rollers, but abandoned on account of the unequal velocity at which the greatest and least diameters of
the rollers travelled.
In the present method of manufacturing the patent welded tube, the end of the skelp is bent to the
circular form, its entire length is raised to the welding heat in an appropriate furnace, and as it leaves
the furnace almost at the point of fusion, it is dragged by the chain of a draw-bench, after the manner
of wire, through a pair of tongs with two bell-mouthed jaws; these are opened at the moment of intro-
ducing the end of the skelp, which is welded without the agency of a mandrel.
By this ingenious arrangement, wrought-iron tubes may be made from the diameter of six inches
internally and about one-eighth to three-eighths of an inch thick, to as small as one-quarter inch
diameter and one-tenth bore; and 80 admirably is the joining effected in those of the best description,
that they will withstand the greatest pressures of gas, steam, or water, to which they have been sub-
jected, and they admit of being bent both in the heated and cold state almost with impunity. Some-
times the tubes are made one upon the other when greater thickness is required; but these stout pipes,
and those larger than three inches, are comparatively but little used.*
Various articles with large apertures are made, not by punching or cutting out the holes, but by
folding the metal around the beak-iron, and finishing them upon a triblet of the appropriate figure; thus
the complete smithy is generally furnished with a series of cones turned in the lathe, for making rings,
the ends of which are folded together and welded, such as Fig. 1799. The same rings, when made of
such cast-steel as does not admit of being welded, are first punched with a small hole, and gradually
thinned out by blows around the margin, until they reach the diameter sought; but this, like numerous
other works, requires considerable forethought to proportion the quantity of the material to its ultimate
form and bulk, 80 that the work may not in the end become either too slight or too heavy.
Chains may be taken as another familiar example of welding; in these the iron is cut off with a plain
chamfer, as from the annular form of the links their extremities cannot slide asunder when struck;
every succeeding link is bent, introduced, and finally welded. In some of these welded chains the
links are no more than half an inch long, and the iron wire one-eighth of an inch diameter several
inches of such chain are required to weigh one pound; these are made with great dexterity by a man
and a boy at a small fire. The curbed chains are welded in the ordinary form and twisted alterwards,
a few links being made red-hot at a time for the purpose.
The massive cable-chains are made much in the same manner, although partly by aid of machinery.
The bar of iron, now one, one and a half, or even two inches diameter, is heated, and the scarf is made
as a plain chamfer by a cutting machine; the link is then formed by inserting the end of the heated bar
within a loop in the edge of an oval disk, which may be compared to a chuck fixed on the end of a
lathe mandrel. The disk is put in geer with the steam-engine; it makes exactly one revolution, and
throws itself out of motion; this bends the heated extremity of the iron into an oval figure: afterwards
it is detached from the rod with a chamfered cut by the cutting machine, which at one stroke makes the
second scarf of the detached link, and the first of that next to be curled up.
The link is now threaded to the extremity of the chain, closed together, and transferred to the fire,
the loose end being carried by a traverse crane; when the link is at the proper heat, it is returned to
the anvil, welded, and dressed off between top and bottom tools, after which the cast-iron transverse stay
is inserted, and the link having been closed upon the stay, the routine is recommenced. The work
A piece of tube of the smallest dimensions, and fourteen feet long, which has been bent cold almost into the form of
the Gordian knot, may be seen at the Institution of Civil Engineers. The wrought-iron tubes of hydrostatic presses, which
measure about half an inch internally, and one-fourth to three-eighths of an inch thick in the metal, are frequently subjected
to a pressure equal to four tons on each square inch. Pipes proved to the same degree are also used in Mr. Perkins' patent
apparatus for warming buildings, and in his recently patented steam-boiler. The safety of each of these is entirely secured
by a fusible plug. which melts and allows the water to escape into the fire when its temperature exceeds any predeter-
mined degree, namely, from about 300° to 600° F,, generally the former.
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commonly requires three men, and the scarf is placed at the side of the oval link, and flatway through
the same. In similar chains made by hand it is, perhaps, more customary to weld the link at the
crown, or small end.
The succeeding illustration of the practice of forging will be that of the formation of a hatchet, Figs.
1800 and 1801, which, like many similar tools, is made by doubling the iron around a mandrel, to form
the eye of the tool; it will also permit the description of some other general proceedings, and likewise
the introduction of the steel for the cutting edge.
1800.
E
1801.
1802.
1803.
1799.
B
F
C
G
I
J
D
H
In making the hatchet, a piece of flat iron is selected, of the width of A E, and twice the length of
A D; it is thinned and extended sideways before it is folded together, to form the projections near B
and F, by blows with the pane of the hammer or a round-edged fuller, on the lines A B to EF, but the
metal must be preserved of the full thickness at the part A E, to form the poll of the hatchet, although
a piece of steel is frequently welded on at that part as a previous step. The work is then bent round
a mandrel, Figs. 1802 and 1803, exactly of the section of the eye as seen in Fig. 1801, and the work is
welded across the line BF; the mandrel is again introduced, and the eye is perfected.
A slip of shear-steel, equal in length to DH, is next inserted between the two tails of the iron, as
yet of their original size, up to the former weld, and all three are welded together between D H:
the combined iron and steel are now drawn out sideways, by blows of the pane of the hammer on and
between CD and G H, to extend them together to IJ. The tool is then flattened and smoothed with
the face of the hammer, and the edges are pared with straight or circular chisels to the particular
pattern, and trimmed with a round-faced hammer, or a top fuller.
In smoothing off the work, the smith pursues his common method of first removing with a file the
hard black scales that appear like spots when the work is removed from the fire; he then dips the
hammer in the slake trough, and lets fall upon the anvil a few drops of the water it picks up, the ex-
plosion of which, when the red-hot metal is struck upon it, makes a smart report and detaches the
scales that would be otherwise indented in the work. It should be observed that the mandrel, Fig.
1802, is purposely made very taper, and is introduced into the hole from both sides, so that the eve
may be smaller in the middle; when, therefore, the handle of the tool is carefully fitted and wedged in,
the handle is, as it were, dovetailed, and the tool can neither fly off nor slip down the handle; the same
mode is also adopted for the heads of hammers.
In spades, and many similar implements, the steel is introduced between the two pieces of iron of
which the tools are made; in others, as plane irons and socket chisels, it is laid on the outside, and the
two are afterwards extended in length or width to the required size. The ordinary chisel for the smith's
shop is made by inserting the steel in a cleft, as in Fig. 1794, and 80 is also the pane of a hammer; but
the flat face of the hammer is sometimes stuck on whilst it continues at the extremity of a flat bar of
steel; it is then cut off, and the welding is afterwards completed. At other times the face of the
hammer is prepared like a nail, with a small spike and a very large head, 80 as to be driven into the
iron to retain its position, until finally secured by the operation of welding.
In putting a piece of steel into the end of an iron rod to serve for я centre, the bar is heated, fixed
horizontally in the vice, and punched lengthways with a sharp square punch, for the reception of the
steel, which is drawn down like a taper tang or thick nail, and driven in; the whole is then returned
to the fire, and when at the proper heat united by welding, the blows being first directed as for forming
a very obtuse cone, to prevent the piece of steel from dropping out.
For some few purposes the blistered steel is used for welding, either to itself or to iron. It is true
the first working under the hammer in a measure changes it to the condition of shear-steel, but less
efficiently so than when the ordinary course of manufacture is pursued, as the hammering is found to
improve steel in a remarkable and increasing degree.
The tires of wrought-iron wheels for locomotive engines and carriages, are in general bent to the circle by somewhat
analogous means to those employed in chain-making, as are likewise the skelps for the twisted barrels of guns: the latter
only require a mandrel or spindle with a winch handle at the one extremity, and a loop for the end of the skelp, which is
wound in contact with the mandrel by means of a fixed bar placed near the same; such barrels are colled up in three
lengths, which are joined together after the spirals are welded.
Wheels for railways display many curious examples of smithing: thus some, except the nave, are made entirely by
welding; others are partly combined with rivets; in all, the nave or boes is a mass of cast-iron usually poured around the
ends of the spokes, with the exception of Bourne and Bartley's patent wheel, in which the nave, spokes, and periphery, are
made entirely of wrought-iron and welded together.
The common practice of welding the tires of railway wheels is now as follows: the tires are cut off with ridges in the
centre, so as in meeting to form two angular notches, into which two thin iron wedges are subsequently welded radially;
the four parts thus united together in the form of a cross, make a very secure joint without the necessity for upsetting the
iron, which would distort the form of the tire.
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For the majority of works in which it is necessary to weld steel to iron, or steel to steel, the shear, or
double shear, is exceedingly suitable; it is used for welding upon various cutting tools, as the majority
of the cast-steel will not endure the heat without crumbling under the hammer. Shear-steel is also
used for various kinds of springs, and for some cutting tools requiring much elasticity.
It is more usual to reserve the cast-steel for those works which the process of welding is not
required, although of late years mild cast-steel, or welding cast-steel, containing a smaller proportion of
carbon has been rather extensively used; but in general the harder the steel the less easily will it
admit of welding, and not unfrequently it is altogether inadmissible.
The hard or harsh varieties of cast-steel are somewhat more manageable when fused borax is used as
a defence instead of sand, either sprinkled on in powder or rubbed on in a lump; and cast-steel, other-
wise intractable, may be sometimes welded to iron by first heating the iron pretty smartly, then
placing the cold steel beside it in the fire, and welding them the moment the steel has acquired its
maximum temperature, by which time the iron will be fully up to the welding heat. When both are
put into the fire cold alike, the steel is often spoiled before the iron is nearly hot enough, and therefore
it is generally usual to heat the iron and steel separately, and only to place them in contact towards
the conclusion of the period of getting up the heat. In forging works either of iron or steel, the uni-
formity of the hammering tends greatly to increase and equalize the strength of each material and in
steel, judicious and equal forging greatly lessens also the after-risk in hardening.*
Concluding remarks on forging; and the applications of heading tools, swage tools, punches, &c.-
With the utmost care and unlimited space, it would have been quite impossible to have conveyed the
instructions called for, in forging the thousand varieties of tools and parts of mechanism the smith is con-
tinually called upon to produce; and all that could be reasonably attempted in this place, was to convey
a few of the general features and practices of this most useful and interesting branch of industry. It is
hoped that such combinations of these methods may be readily arrived at as will serve for the majority
of ordinary wants.
The smith in all cases selects or prepares that particular form and magnitude of iron, and also adopts
that order of proceeding which experience points out as being the most exact, sound, and economical.
In this he is assisted by a large assortment of various tools and moulds for such parts of the work as
are often repeated, or that are of a character sufficiently general to warrant the outlay, and to some of
which I will advert.
The heading tools, Figs. 1777 and 1778, are made of all
sizes and varieties of forms; some with a square recess to
1804.
produce a square beneath the head, to prevent the bolt from
being turned round in the act of tightening its nut; others for
countersunk and round-headed bolts, with and without square
shoulders: many similar heading tools are used for all those
parts of work which at all resemble bolts, in having any
0000
sudden enlargement from the stem or shaft. The holes in the
swage-block, Fig. 1790, are used after the manner of heading
tools for large objects; the grooves and recesses around its
margin, also serve in a variety of works as bottom swages
beyond the size of those fitted to the anvil. At the opposite
extreme of the heading tools, as to size, may be noticed those
constantly employed in producing the smallest kinds of nails,
brads, and rivets, of various denominations; some of which
heading tools divide in two parts like a pair of spring for-
ceps, to release the nails after they have been forged. These
kinds are called wrought-nails and brads, in contradistinction
to similar nails cut out of sheet-iron by various processes of
shearing and punching, which latter kinds are known as cut-
brads and nails.
The top and bottom rounding tools, Fig. 1774, are made of all diameters for plain cylindrical works
and when they are used for objects the different parts of which are of various diameters, it requires
much care to apply them equally on all parts of the work, that the several circles may be concentric
and true one with the other, or possess one axis in common. To ensure this condition some of these
rounding tools are made of various and specific forms, for the heads of screws, for collars, flanges, or
enlargements, which are of continual occurrence in machinery; for the ornamental swells or flanges
about the iron work of carriages, and other works. Such tools, like the pair represented in Figs. 1805
and 1806, are called swage or collar tools; they save labor in a most important degree, and are thus
made. A solid mould, core, or striker, exactly a copy of the work to be produced, is made of steel by
hand-forging, and then turned in the lathe to the required form, as shown in Fig. 1807.
When cast-steel has been spolled by overheating, it may be partially recovered by four or five reheatings and quench-
ings in water, each carried to an extent a little less and less than the first excess; and lastly. the steel must have a good
hammering at the ordinary red heat. Some go so far as to prefer for cutting tools the steel thus recovered, but this seems
a most questionable policy, although the change wrought by this treatment is really remarkable; as the fragment broken
off from the bar in the spoiled state, and another from the same bar after part restoration and hardening, will exhibit the
extreme characters of coarse and fine.
The hammering we suspect to be the principal requisite, and in superior tools it should be continued until the work IS
nearly cold, to produce the maximum amount of condensation before hardening; but no hammering will restore the loss
of tenacity consequent upon the overheating. or even the too frequent heating, of steel, without excess.
+ The forge used by the nail-makers is built as a circular pedestal, with the fire in the centre and the chimney directly
over it; the rock-staff of the bellows extends entirely around the forge, 80 that one of the four or five persons who work
at the same fire is continually blowing it, whence the fire is always at the heat proper for welding, and which keeps the
nails sound and good.
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FORTIFICATION.
The top tool is first moulded to the general form in an appropriate aperture in the swage-block, Fig.
1804; it is faced with steel like a hammer, and the core, Fig. 1807, is indented into it; the blows of the
sledge-hammer not being given directly upon the core, but upon some hollow tool previously made;
otherwise the core must be filed partly flat to present a plane surface to the hammer. The bottom
tool, which is fitted to the anvil, is made in a similar manner, and sometimes the two are finished at the
same time whilst hot, with the cold striker between them; their edges are carefully rounded with a file
so as not to cut the work, and lastly they are hardened under a stream of water.
In preparing the work for the collar tools, when the projection is inconsiderable, the work is always
drawn down rudely to the form between the top and bottom fullers, as in Fig. 1772; but for greater
economy, large works in iron are sometimes made by folding a ring around them, as in Fig. 1780. The
metal for a large ring is occasionally moulded in a bottom tool, like Fig. 1808, and coiled up to the
shape of Fig. 1809, after which it is closed upon the central rod between the swages, and then welded
within them. The tools are slightly greased, to prevent the work from hanging to them, and from the
same motive their surfaces are not made quite flat or perpendicular, but slightly conical, and all the
angles are obliterated and rounded.
1809.
1805.
1812.
1808
1811.
1810.
1807.
1806
The spring swage tool, represented in Fig. 1810, is used for some small manufacturing purposes; it
differs in no respect from the former, except in the steel spring which connects the two parts; it is
employed for light single hand-forgings. Other workmen use swage tools, such as Fig. 1811, in which
there is a square recess in the bottom tool to fit the margin of the top tool so as to guide it exactly to
its true position; * this kind also may be used for single hand works, and is particularly suited to those
which are of rectangular section, as the shoulders of table-knives: these do not admit of being twisted
round, which movement furnishes the guide for the position of the top tool in forging circular works.
The smith has likewise a variety of punches of all shapes and sizes, for making holes of corresponding
forms; and also drifts or mandrels, used alone for finishing them, many of which, like the turned cones,
are made from a small to a large size to serve for objects of various sizes. Two examples of the very
dexterous use of punches are in the hands of almost every person, namely, ordinary scissors and pliers.
The first are made from a small bar of flat steel the end is flattened and punched with a small round
hole, which is gradually opened upon a beak-iron, Fig. 1812, attached to the square hole of the anvil;
the beak-iron has a shallow groove (accidentally omitted) for rounding the inside of the bows. The
remaining parts of the scissors are moulded jointly by the hammer and bottom swage tools; but the
bows are mostly finished by the eye alone.
In the Lancashire pliers, the central half of the joint is first made; the aperture in the other part is
then punched through sideways, and sufficiently bulged out to allow the middle joint to be passed
through, after which the outsides are closed upon the centre. This proceeding exhibits, in the smallest
kinds especially, a surprising degree of dexterity and dispatch, only to be arrived at by very great
practice; and which in this and numerous other instances of manufacture could be scarcely attained but
for the enormous demand, which enables a great subdivision of labor to be successfully applied to their
production.
FORTIFICATION is the art of constructing such works of defence as may enable a comparatively
small number of men to maintain possession of a city or place against the assaults of a superior force.
Modern fortifications, though differing in some subordinate details, which differences are dignified by the
name of systems, closely resemble one another in all their essential parts. In order to explain their
structure, it will be convenient to consider them first without reference to their form, or the position of
the ground lines in respect of each other, but merely as defences against an army with artillery ad-
vancing directly in front. The annexed figure repre-
sents a vertical section of a regular fortification on the
G
D
1813.
ground line X Y, the place to be defended being sup-
B
H
C
posed between X and A. The mass of earth ABCD
R
M
P
EFGH forms the rampart with its parapet. A B is
L
the interior slope of the rampart; BC is the terre-plein
of the rampart, having a breadth of about 40 feet, on which the troops and cannon are placed DE is
called the banquette, or step, on which the soldiers mount to fire over the parapet; EFG is the
. In practice the recess in the bottom tool would be deeper, and taper or larger above to guide the tool more easily to its
place; but if so drawn the figure would have been less distinct.
+ The remarks on steel also refer to the necessity of good primary forging and hammering to produce homogenelty;
and also to many of the other points generally admitted by practical men as being conducive to the success of hardening.
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parapet, of a height (about 7 feet) sufficient to protect the men and guns on the terre-plein, and sloped
in the direction F G towards M, the opposite edge of the ditch, so that a man approaching there may
be seen and fired at; G H is the exterior slope of the parapet; HI is the revetment, or wall of masonry
supporting the rampart, and strengthened by buttresses placed at small intervals behind it. This
must be of sufficient height to prevent its being easily scaled; but yet must not rise higher than the
edge of the exterior work at Qn in order that it may not be seen and breached by distant batteries.
The exterior front of the rampart, covered with the revetment HK, is called the escarp; M is
the ditch, the dimensions of which will be determined by the nature of the ground, but must be such,
in general, that its excavation or deblai must produce sufficient earth or remblai to form the rampart
the opposite side of the ditch LM is the counterscarp, also supported by a revetment of masonry MN
is the covered way, a space about 10 yards in breadth, having a banquette NOP, and protected by a
parapet PQ, the superior slope of which, QR, is called the glacis. The use of the covered way is to
allow troops to be drawn up, unseen by the besiegers, for the purpose of making sorties; it also enables
the garrison to keep up a closer fire on the approaches of the enemy, and its parapet forms a strong
protection to the revetment of the rampart.
It is easy to see that the strength of a place will be increased by a succession of such works, so that
when the besieged are driven from one they may retire to the next behind it. Sometimes there are
three ditches with intermediate works, or rather works raised within the ditch itself, similar to the
rampart, though of a less height, in order that the guns on the rampart may range above them. A
work of this sort, between the inner and the main ditch, is called a tenaille; that between the main
ditch and the outer ditch is called a ravelin. All works outside the ditch are called outworks.
Before proceeding to construct a fortification, it is necessary to lay down a plan. This will differ in
some respects according to the system adopted; but the following description, which properly belongs
to Vauban's First System, will explain the general method When the work is regular, the sides are
all equal, and therefore the general form will be that of a polygon inscribed in a circle. The first thing
to be done is to determine on the number of sides. We shall suppose them to be six, and the radius of
the circumscribing circle to be 360 yards, when the
construction will be as follows: Let A B, be two
1814.
sides of a hexagon inscribed in a circle; each of
B
these lines will be equal to the radius, or 360 yards.
Bisect A B in D; draw the perpendicular DE, on
I
which set off DE, equal to one sixth of A B or 60
yards; draw the lines EF and BEG, in which
F
take A H and BI, each equal to 100 yards, or five
H
ninths of D; make H F and IG each equal to the
distance HI; then the line A HGFIB is the prin-
cipal outline of the front; and by making the same
construction on each of the sides of the hexagon, we obtain the principal outline of the whole forti-
fication, or that by which the first figure of the work is defined.
The part F IBK L is called the bastion, BI and BK are the faces of the bastion; IF and KL are its
flanks; F L is the gorge; GF is the curtain; A F and BG are the lines of defence; B is the flanked
angle; I and K are the angles of the shoulder; GFL and M the angles of the flank. From the points
A and B as centres, and a radius of 40 yards, describe circular arcs; if lines be drawn from the oppo-
site angles of the shoulder HI to touch those arcs, the parts of those lines a c, b c, together with the arcs,
will represent the counterscarp of the ditch. The curtain is defended by a ravelin, which is constructed
thus: From c, the re-entering angle of the counterscarp, set off, on the perpendicular DE, a line c d,
equal to 110 yards, and from d draw de, df, in the directions of H and I, to meet the counterscarp; then
de and df are the faces of the ravelia, and oe and cf its semi-gorges. The counterscarp ghi of the
ditch of the ravelin is parallel to its faces, and rounded off at h. Stairs, called pas-de-souris, are con-
structed to facilitate the descent from the ravelin to the ditch. Besides the ravelin, there is usually
another appendage to the bastion and curtain. This is the tenaille, represented in the figure by the
parts Pq made in the direction of the lines of defence; but it has sometimes other forms. The tenaille
is made in the ditch before the curtain, with passages between the ends and the flanks of the bastion.
It is a low work, having its parapet only about three feet higher than the level ground of the ravelin,
and its use is to defend the bottom of the ditch by a grazing fire.
Such are the works which form the envelop of the place fortified; but various other constructions are
in most cases added, according to the nature of the ground and other circumstances, for the purpose of
protecting or strengthening such parts as are most exposed, or of interrupting the works of the be-
siegers. These additional constructions are either internal or external. Among the former are retrench-
ments of various kinds, either constructed at the same time with the principal works or thrown up
during the siege. They are made behind the ramparts, or the bastions most exposed to attack, their
use being to enable the garrison to continue the defence from behind a fresh obstacle when a rampart
or bastion has been breached. When a hill or rising ground overlooks any of the works, a cavalier is
raised, about ten or twelve feet higher than the rest of the works. This is commonly placed within
the bastion when it has the same form, but sometimes on the middle of the curtain when its form is
semicircular. Of the exterior works one of the most important is the counter-
1815.
guard, constructed to cover some of the principal parts, as the bastion or the
cavalier, in such a manner that without obstructing their fire it prevents them
from being breached till itself is taken. The counterguard is constructed paral-
lel with the faces of the work it is destined to cover; and it must be lower than
the principal work, though of a sufficient height to screen its revetment. A horn-
work, represented in the annexed figure, is composed of two branches, and a front
composed of two half bastions and a curtain, resembling a front of the body of
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FORTIFICATION.
the place. It is here represented as made before the curtain, but it may be also constructed before a
bastion. A crown-work is of the same nature as a horn-work, but larger, and having two fronts, which
give it somewhat the appearance of a crown. Horn-works and crown-works are constructed where a
large spot of ground lies beyond the fortification which might be advantageous to an enemy, or to cover
a gate or entrance into a town. Lunettes, a a, are placed on both sides of the ravelin, and are con-
structed on lines bisecting the faces of the ravelin at right angles. A bonnet, b, is a
1816.
work covering the salient angle of the ravelin. Tenaillons are similar in construc-
tion to lunettes, but having one of their faces formed on lines which are the produc-
tion of the faces of the ravelin, instead of bisecting those faces. The application of
all these and other works of a similar description depends on the nature of the lo-
calities; and it must be left to the judgment of the engineer to determine in each particular case which
is best adapted to the ground.
We have already alluded to the use and importance of the covered way. In order to increase its
strength traverses, or portions of parapet, are thrown across it, which screen it from an enfilading fire,
and enable the defenders to dispute its possession foot by foot. Places of arms, or places for assem-
bling troops, and protected by traverses and redoubts, are also formed on it at the re-entering and salient
angles of the counterscarp. The redoubts serve not only as a place of retreat, but facilitate the making
of sorties upon the enemy's lodgments.
The descriptions given above belong more especially to that method of fortification which, in the mili-
tary schools, is denominated Vauban's first system. In his second system,
represented in the annexed figure, he separated the bastions from the body
1817.
of the place by a ditch about 40 feet wide, in order that the besieger, after
the breach and capture of the bastions, might be compelled to renew his
operations against his enceinte or body of the place. The angles of the
polygon are crowned by pentagonal towers of masonry, called tower bastions,
to which, in fact, the regular bastions only form countergards. Vauban's
third system does not differ in any material respect from the second. He
1818.
increased the size of the ravelin, and gave it a redoubt. The tower bastions
were likewise made larger, and the curtain which united them was broken
inwards, so as to form two small flanks underneath; while casements for
cannon were constructed, to co-operate with those of the tower bastions in
the defence of the ditch.
Coehorn's system.-Contemporary with Vauban was the Baron de Coehorn, director-general of the
fortifications of the United Provinces of Holland. This celebrated engineer is also the author of three
different systems, though the third has never been constructed. His methods are only applicable in
low swampy countries, like Holland and the object which he kept principally in view was to throw
such obstacles in the way of a besieging force that the place could only be
approached with great difficulty and hazard. This he sought to accomplish
1819.
by covering and flanking his works more effectually than had previously
been done, and by depriving the assailant of the room necessary for erect-
ing his batteries. An idea of his methods may be formed from the annex-
ed figure, which represents his first system. It is constructed on a hexa-
gon the second was on a heptagon, and the third on an octagon. And it
may be remarked of his systems in general, that they differ from Vauban's principally in the greater
width of the ditch and the narrow space between the flanks.
Cormontaigne's system.-The methods of Vauban were improved in many essential respects by Cor-
montaigne. In his system, which is here represented, the faces of the bastion are
1820.
made longer than in Vauban's methods, and the flanks are placed at right angles
with the faces of the opposite bastions. The enlargement of the bastion renders it
capable of containing interior retrenchments; and the flanks, though shortened. are
better covered. His ravelins are also constructed on a larger base, and contain a
larger redoubt, from which the besiegers can keep up a reverse fire on breaches
made in the collateral bastions; 80 that the assault upon the latter becomes impracticable until the
ravelin and its redoubt are both captured. The combination round the extremities of the traverses of
the covered way are arranged in a zigzag line ; so that the passage round the extremity of one traverse
is defended by the fire of another in its rear, and the advance of the assailants along the covered way
thereby checked. In general, Cormontaigne's system possesses greater defensive properties, and IS
more economical of materials.
Modern System.-Fig. 1821 represents what is called the modern system it varies but little from
that of Cormontaigne. The ravelin is made to cover the shoulder of the bastion more effectually by a
greater projection, and its faces are retrenched by coupures or cuts through the rampart, perpendicular
to the faces of the bastion, which prevent the enemy
1821.
from taking the redoubt in the re-entering place of
arms without first possessing himself of the redoubt in
the ravelin.
All the systems above enumerated agree in their
principal features, and may be included under the name
of the bastion system. Some engineers, however, have
pointed out defects which appear to be inherent in the
system, and proposed to give the polygon a different
form. By suppressing the curtain and the tenaille, and
producing the faces of the bastions inward, a line of
rampart would be formed presenting simply a succession of salient and re-entering angles. But as the
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plan has never been practically carried into effect, it is unnecessary to enter into particulars. In the
present state of the military art, such is the superiority of the means of attack over those of defence,
that however strong the works may be, and however skilfully disposed, their reduction, when assailed
by adequate means, is, generally speaking, a matter of absolute certainty. The besieging army, shel-
tered by its trenches from the missiles of the garrison, advances in zigzag lines parallel to the faces of
the ramparts, till it passes over or circumvents all the exterior defences of the place, and arrives at the
main wall, where a breach has been made by batteries erected for the purpose. To this covered mode
of attack, supported by the ricochet batteries, by which the defenders are driven from the ramparts and
the guns dismounted, it is perhaps impossible to offer any effectual resistance. Indeed, such is the per-
fection to which the art of attack has been reduced, that even the length of time which any fortress will
be able to hold out against an enemy provided with the proper train of sappers and miners, and the
implements necessary for carrying on their operations, may be computed with the greatest precision.
Field fortification.-Field fortification is the art of constructing all kinds of temporary works for
assisting the operations of an army in the field, and enabling it to maintain a position against a superior
force. On account of the endless varieties and accidents of the ground, the observance of fixed rules is,
indeed, impracticable: nevertheless there are certain general maxims which apply to the construction
of fortifications of all kinds, whether temporary or permanent. For example, works constructed to flank
others, must not be at so great a distance as to be beyond the effective range of musketry the angles
of defence should be nearly right angles, and the salient angles as obtuse as possible. The general na-
ture of defensive works is also the same in all cases, namely, a ditch and a parapet; though, as the
pickaxe and the spade are the only implements which an army in the field can carry about with it, the
depth and width of the ditch and the height of the parapet are in field-works necessarily limited to
what can be effected by these simple means.
Field-works are usually divided into three classes 1, works open at the gorge; 2, works inclosed all
round; and 3, lines either continued or with intervals. To the first class belong redans, single and dou-
ble, tenailled heads, and bastioned heads; to the second, redoubts, star forts, and
1822.
bastioned forts; and to the third, lines of various kinds for defending a position.
The redan is the simplest of all works, consisting merely of two lines, A B and A C,
forming an angle with each other. It is only employed for such purposes as defend-
ing the avenues of a village, bridge, or defile. The length given it is usually about
B
C
50 yards. When the redan is thrown out in front of other works it is called a fleche,
D
or arrow. Lunettes are also applied for similar purposes, and are formed by adding
two parallel faces, BD and C E, to the redan, at the extremities of its open flanks.
1823.
The double redan, or bonnet de prêtre, consists of two faces, A B and CD; and two
A
c
flanks A E and CE, usually shorter than the faces, and affording a reciprocal defence
E
to each other. The re-entering angle at E should be a right angle; if it is less, the
two flanks are in danger of being struck by each other's fire; and if it is much greater
B
than a right angle, the defence will be weakened; for it is found by experience that soldiers placed be-
hind a screen invariably fire straight before them, or at right angles to the screen. When a greater
extent of front is to be fortified, the lines are disposed in the form of bastions or tenailles, and thence
called bastioned heads, and tenailled heads.
Redoubts are works closed on all sides, of a polygonal or quadrilateral figure, and usually square.
An opening is left in one of the sides, for communication with the exterior, and a traverse is thrown up
within for protection. As the work is without flanks, the ditches are left without defence. The angles
are sometimes rounded, or cut off, in order that a fire may be maintained on an as-
1824.
sailant advancing in the direction of the diagonal.
Star forts are inclosed works constructed upon an equilateral triangle or a square.
In the former case they have six points, in the latter eight. When constructed on a
square, each of the sides (which may be about 90 vards long) is divided into three
equal parts, and on the middle part an equilateral triangle is constructed, which gives
the trace of the figure. The object of this work is to remedy the defects of the redoubt
by flanking the angles of the square; but as a-considerable space is consumed by the
re-entering angles, it scarcely admits of sufficient troops and artillery being placed in it for its defence.
Bastioned forts are constructed in the field on the same principles as in permanent works; but are
only constructed on the square or pentagon. The distance A B, or exterior side of the polygon, should
not exceed the range of musketry, or about 200 yards. They are employed only
1825.
in fortifying important position: and require, accordingly, to be constructed in a
more solid manner than other works of a temporary nature.
The last class of field-works comprehends lines of various descriptions. Con-
tinued lines are constructed to inclose a front, or connect principal works with one
another by a continued parapet. They are constructed, according to circumstances,
with redans, tenailles, or bastions, placed at certain intervals, seldom exceeding
180 yards. From the descriptions given above, the different forms of the redan
line, tenaille line, and bastion line, will be readily conceived. Sometimes they are
formed of a succession of faces and flanks at right angles. In this case they are called lines-encremail-
lières. The flanks are about a fourth of the length of the faces, and afford a defence to the ditches.
Lines with intervals consist of isolated works, as redans or redoubts,
1826.
placed at distances which should not exceed 200 yards, and so as to
afford one another a mutual defence.
Besides the works now enumerated, various expedients are resorted to in order to prevent, or at least
to render more difficult, the approaches of an enemy. Among these are palisades, abatis, trous-de-coup,
chevaux-de-frize, crows' feet, &c.
The principal authors on fortification are Errard, Stevinus, Antoine de Ville, Compte de Pagan, Coe-
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FOUNDATIONS.
horn, Vauban, Mallet, Belidor, Blondel, Montalembert, Bisset, Bousmard, Carnot, Mouzé, &c. For a
practical treatise the reader may be referred to the article " Fortification" in the Encyc. Metropolitana.
Also the works of D. H. Mahan, Professor of Military and Civil Engineering in the United States' Mili-
tary Academy; and of H. W. Halleck, of the U.S. Army.
FOUNDATIONS. In preparing the foundation for any building, there are two sources of failure
which must be carefully guarded against: viz. inequality of settlement, and lateral escape of the sup-
porting material; and, if these radical defects can be guarded against, there is scarcely any situation
in which a good foundation may not be obtained. It is therefore important that previous to the com-
mencement of the work, soundings should be taken to ascertain the nature of the soil and the ray of the
strata, to determine the kind of foundation; and the more important and weighty the superstructure,
the more careful and deeper the examination.
Natural foundations.-The best foundation is a natural one, such as a stratum of rock, or compact
gravel. If circumstances prevent the work being commenced from the same level throughout, the
ground must be carefully benched out, i. e. cut into horizontal steps, so that the courses may all be per-
fectly level. It must also be borne in mind that all work will settle, more or less, according to the
perfection of the joints, and therefore in these cases it is best to bring up the foundations to a uniform
level, with large blocks of stone, or with concrete, before commencing the superstructure, which would
otherwise settle most over the deepest parts, on account of the greater number of mortar joints, and
thus cause unsightly fractures.
Many soils form excellent foundations when kept from the weather, which are worthless when this
cannot be effected. In dealing with soils of this kind nothing is required but to keep them from the
action of the atmosphere. This is best done by covering them with a layer of concrete, (see mortar.)
For want of this precaution many buildings have been fractured from top to bottom by the expansion
and contraction of their clay foundations during the alternations of drought and moisture, of frost and
heat, to which they have been exposed in successive seasons.
Artificial foundations-Where the ground in its natural state is too soft to bear the weight of the
proposed structure, recourse must be had to artificial means of support, and, in doing this, whatever
mode of construction be adopted, the principle must always be that of extending the bearing surface as
much as possible; just in the same way, that, by placing a plank over a dangerous piece of ice, a couple
of men can pass over a spot which would not bear the weight of a child. There are many ways of
doing this-as by a thick layer of concrete, or by layers of planking, or by a net-work of timber, or
these different methods may be combined. The weight may also be distributed over the entire area of
the foundation by inverted arches.
The use of timber is objectionable where it cannot be kept constantly wet, as alternations of dryness
and moisture soon cause it to rot, and for this reason concrete is very extensively used in situations
where timber would be liable to decay.
In the case of a foundation partly natural and partly artificial, the utmost care and circumspection
are required to avoid fractures in the superstructure; and it cannot be too strongly impressed that it is
not an unyielding, but a uniform yielding foundation that is required, and that it is not the amount, so
much as the inequality, of settlement that does the mischief.
The second great principle laid down at the commencement of this article was-To prevent the
lateral escape of the supporting material. This is especially necessary when building in running sand,
or soft clay, which would ooze out from below the work. and allow the superstructure to sink. In soils
of this kind, in addition to protecting the surface with planking, concrete, or timber, it is often necessary
to inclose the whole area of the foundation with piles driven close together; this is called sheet-piling.
Where there is a hard stratum below the soft ground, but at too great a depth to allow of the solid
work being brought up from it without greater expense than the circumstances of the case will allow,
it is usual to drive down wooden piles, often shod with iron, until their bottoms are firmly fixed in the
hard ground. The upper ends of the piles are then cut off level, and covered with a platform of tim-
ber on which the work is built in the usual way. The piles are generally of about 1 foot diameter, and
are driven at distances of from 2 to 3 feet from centre to centre.
Where a firm foundation is required to be formed in a situation where no firm bottom can be found
within an available depth, piles are driven, to consolidate the mass, a few feet apart over the whole
area of the foundation, which is surrounded by a row of sheet-piling to prevent the escape of the soil
the space between the pile heads is then filled to the depth of several feet with stones or concrete, and
the whole is covered with a timber platform, on which to commence the solid work.
Foundations in water.Hitherto we have been describing ordinary foundations; we now come to
those cases in which water interferes with the operations of the builder, oftentimes causing no little
trouble, anxiety, and expense.
Foundations in water may be divided under three heads: 1st, Foundations formed wholly with piles.
2d, Solid foundations laid on the surface of the ground, either in its natural state, or roughly levelled
by dredging. 3dly, Solid foundations laid below the surface, the ground being laid dry by cofferdams.
Foundations formed wholly of piles.-The simplest foundations of this kind are those formed by rows
of wooden piles braced together 80 as to form a skeleton pier for the support of horizontal beams; and
this plan is often adopted in building jetties, piers of wooden bridges, and similar erections where the
expense precludes the adoption of a more permanent mode of construction; an example of this kind is
shown in Fig. 1827.
There is, however, an objection to the use of piles partly above and partly under water, that, from
the alternations of dryness and moisture, they decay at the water-line; and in tidal waters, they are
often rapidly destroyed by the worm.
To obviate the inconveniences attending the use of timber, cast iron is sometimes used as a material
for piles; but this again is objectionable in salt water, as the action of the sea-water upon the iron con-
verts it into a soft substance which can be cut with a knife, resembling the lead used for pencils,
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In situations where a firm hold cannot be obtained for a pile of the ordinary shape, such as shifting
sand, Mitchell's patent screw piles may be used with great advantage. These piles terminate at the
bottom in a large iron screw 4 feet in diameter, which, being screwed into the ground, gives a firm foot-
hold to the pile. This is a very simple and efficient mode of obtaining a foundation where all other
means would fail, and has been used in erecting light-houses on sand-banks with great success.
An ingenious system of cast-iron piling was adopted by Mr. Clark in the erection of the Town Pier
at Gravesend, in forming a foundation for the cast-iron columns, supporting the superstructure of the T
head of the pier. Under the site of each column were driven three cast-iron piles, on which an adjust
ing plate was firmly keyed, forming a broad base for the support of the column, which was adjusted to
its correct position, and bolted down to the adjusting plate.
1827.
SCALE.-20 feet=1 inch.
A kind of foundation on the same principle as piling has been lately much used in situations where
ordinary piling cannot be resorted to with advantage. The method referred to consists in sinking
hollow cast-iron cylinders until a hard bottom is reached. The interior of the cylinder is then pumped
dry, and filled up with concrete or some equally solid material, thus making it a solid pier on which to
erect the superstructure. The cylinders are made in lengths, which are successively bolted together as
each previous length is lowered, the excavation going on at the bottom, which is kept dry by pumping.
It often happens, however, in sinking through sand, that the pressure of the water is 80 great as to
blow up the sand at the bottom of the cylinder; and, when this is the case, the operation is carried on
by means of a large auger, called a miser, which excavates and brings up the materials without the
necessity of pumping out the water. The lower edge of the bottom length of each cylinder is made
with я sharp edge, to enable it to penetrate the soil with greater ease, and to enter the hard bottom
stratum on which the work is to rest. This method was adopted by Mr. Redman in the erection of the
Terrace pier at Gravesend.
Before closing our remarks on pile foundations, we must mention a very curious system of carrying
up a foundation through loose wet sand, which is practised in India and China, and is strictly analogous
to the sinking of cast-iron cylinders just described.
It consists in sinking a series of wells close together, which are afterwards arched over separately,
and covered with a system of vaulting, on which the superstructure is raised. The method of sinking
these wells is to dig down, as far as practicable, without a lining of masonry, or until water is reached;
a wooden curb is then placed at the bottom of the excavation, and a brick cylinder raised upon it to the
height of 3 or 4 feet above the ground. As soon as the work is sufficiently set, the curb and the super-
incumbent brick-work are lowered by excavating the ground under the sides of the curb, the peculiarity
of the process being that the well-sinker works under water, frequently remaining submerged more
than a minute at a time. These cylinders have been occasionally sunk to a depth of 40 feet.
Solid foundations simply laid on the surface of the ground.-Where the site of the intended struc-
ture is perfectly firm, and there is no danger of the work being undermined by any scour, it will be
sufficient to place the materials on the natural bottom, the inequalities of surface being first removed by
dredging or blasting.
Pierre perdue.-The simplest mode of proceeding is to throw down masses of stone at random over
the site of the work until the mass reaches the surface of the water, above which the work can be car-
ried on in the usual manner. This is called a foundation of pierre perdue," or random work, and is
used for breakwaters, foundations of sea-walls, and similar works. Plymouth breakwater is an example
on a large scale.
Coursed masonry.-Another way, much used in harbor work, is to build up the work from the bot-
tom (which must be first roughly levelled) with large stones, carefully lowered into their places; and
this is a very successful method where the stones are of sufficient size and weight to enable the work
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FOUNDATIONS.
to withstand the run of the sea. The diving-bell affords a ready means of verifying the position of each
stone as it is lowered.
Béton.-On the continent, foundations under water are frequently executed with blocks of béton or
hydraulic concrete, which has the property of setting under water. The site of the work is first inclosed
with a row of sheet piling, which protects the béton from disturbance until it has set. This system is
of very ancient date, being described by Vitruvius, and was practised by the Romans, who have left
us many examples of it on the const of Italy. The French engineers have used béton in the works at
Algiers, in large blocks of 324 cubic feet, which were floated out and allowed to drop into their places
from slings. This method, which proved perfectly successful, was adopted in consequence of the
smaller blocks first used being displaced and destroyed by the force of the sea.
Caissons.-A caisson is a chest of timber, which is floated over the site of the work, and, being kept
in its place by guide piles, is loaded with stone until it rests firmly on the ground. In some cases the
stone is merely thrown in, the regular masonry commencing with the top of the caisson; which is sunk
a little below the level of low water, so that the whole wood-work may be always covered, and the
caisson remains as part of the structure. In others, the masonry is built on the bottom of the caisson,
and when the work reaches the level of the water the sides of the caisson are removed.
Westminster Bridge, London, is a noted instance of the failure of this method of building. The bot-
tom of the river has been scoured out to a depth of several feet since the erection of the bridge; and
the foundations of the piers remained in a dangerous state until they were secured by driving sheet
piling all around them, and underpinning the portions which had been undermined.
An improvement on the above method consists in dredging out the ground to a considerable depth,
and putting in a thick layer of béton on which to rest the bottom of the caisson.
There is a third method of applying caissons which is practised in Europe, and which is free from
the objections which commonly attend the use of caissons. A firm foundation is first formed by driving
piles a few feet apart over the whole site of the foundation. The tops of the piles are then sawn off
under water just enough above the ground to allow of their being all cut to the same level. The cais-
son is then floated over the piles, and, when in its proper position, is sunk upon them, being kept in its
place by a few piles left standing above the others, the water being kept out of the caisson by a kind
of well constructed round each of these internal guide piles, which are built up into the masonry. This
method of building in caissons on pile foundations is shown in Figs. 1828 and 1829. The piers of the
Pont du Val Benoit at Liége, which carries the railway across the Meuse, have been built on pile foun-
dations in the manner here described.
1829.
WATER
SUMMER
1828.
BOTTOM
OF
CAISSON
WELL
A similar plan of foundation was adopted in the construction of three of the piers of the railroad
bridge across the Connecticut, at Springfied, Mass. but to give the greatest stability to the work, the
bottom was previously dredged, the piles were then driven, and cut off level considerably below the
bed of the river. The spaces between the piles, and a few feet outside of them, was filled with béton,
and raked off even with the top of the piles; the caisson was then floated into its position. The foun-
dations of the other piers and abutments were of piles, but cofferdams were used, and the bottom laid
dry and excavated.
1830.
FLOOD
WATER
PUDDLE
PIER
SUMMER
WATER
LOUSE
GRAVEL
SCALE.-20 feet=1 inch.
Solid foundations laid in cofferdams.-There are many circumstances under which it becomes neces-
sary to lay the bottom dry before commencing operations. This is done by inclosing the site of the
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FOUNDRY CRANE.
703
foundation with a water-tight wall of timber, from within which the water can be pumped out by steam
power or otherwise. Sometimes, in shallow water, an earth embankment or a single row of sheet piles
only is sufficient; but in deep water two or even four rows of piles will be required, the space between
them being filled in with puddle, 80 as to form a solid water-tight mass, Fig. 1830. The great difficul-
ties in the construction of a cofferdam are-1st, to
keep it water-tight; and, 2d, to support the sides
1831.
against the pressure of the water outside, which in
tidal waters is sometimes 80 great as to render it
necessary to allow a dam to fill to prevent its being
crushed. Of the difficulties experienced in the con-
struction of a cofferdam in deep water, and of the
excavation for foundations, an interesting and in-
structive example may be found in the able report
of Captain Turnbull, on the construction of the Poto-
BETON
mac Aqueduct, published in the Civil Engineers' and
Architects' Journal.
In order to save timber, and to avoid the difficulty
of keeping out the bottom springs, it has been pro-
posed by a French engineer, after driving the outer
row, to dredge out the area thus inclosed, and fill it up to a certain height with béton. The cofferdam
is then to be completed by driving an inner row of piles resting on the béton, and puddling between
the two rows in the usual manner; and the masonry is carried up on the béton foundation thus pre-
pared. This construction is shown in Fig. 1831. See Day Dock.
FOUNDRY See CASTING.
FOUNDRY CRANE Fig. 1832.-Side elevation of the crane, and section of the masonry which sup-
ports it.
Fig. 1833.-Elevation of the geer side taken at right angles to Fig. 1832.
Fig. 1884.-Horizontal section on the line 1-2, Fig. 1832. Fig. 1835.-Section on the line 3-4.
S
s
1834.
t
E
0
M
1833.
R
850
1835.
S
1832.
A
1000 G
400
g
R
I
I
E
E
h
9
h
0
0
1843.
A
4
P
2
1
B
325
A
A
1844.
6
?
a
K
[
F
5
!
K
G
aug
1836.
C
0
0
510
S60
720
D
D
09114
D
006
n
A
J
280
D
SCALE.-17 feet=4 inches.
Fig. 1836.-Elevation of geers and pinions.
Fig. 1887.-Shows the arrangement of the break; Fig. 1838.-A section of the same.
Figa 1839 and 1840.-Horizontal section on the line 5-6; Fig. 1839 being the section of the frame
which supports the geering; Fig. 1840, the section of the body or shaft of the crane.
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FREEZING APPARATUS.
Fig. 1841.-Plan of the cast-iron plate and friction wheels against which the shaft of the crane bears,
and which facilitate its rotation. Fig. 1842.-Section of this plate on the broken line 7-8-9.
Figs. 1843 and 1844.Show a different arrangement of steps from that already given, Figs. 1832 and
1833.
Explanatory Letters.
A, vertical shaft or body of the crane cast in one piece; a, a steel point (easily replaced when worn)
at the lower end of the shaft, Fig. 1843. This step is cast with the base, and in Fig. 1844 it is steel,
and fitted in the base plate.
B, cast-iron base or step-plate; a, steel step; b, ribe to strengthen the shaft; c, cylindrical-turned
collar, against which the six strong cast-iron friction wheels d bear, maintaining the shaft perpendicular,
and allowing it to turn freely.
C, large plate cast in one piece, containing the wheels d; e, small corner pieces to strengthen the cast-
ing; f, man-hole to get at the step.
D, the masonry, in which is formed a circular well for the admission of the shaft A.
E, the oaken arm of the crane, supported by a strong brace F; g', shoes or sockets cast with the
shaft, which receive the feet of the arm and brace. Fig. 1835 shows the same in section. h, an iron
strap inclosing the top of the shaft and bolted securely to the arm E.
1841.
1838.
1837.
1840.
C
1839.
a
J
°d
300
50+
9
600
8
1842.
c
2
les
260
c
E
O
C
P
P
1.270
G, two cast-iron frames for the support of the geering, attached by bolts to the body of the crane
through the ears i; jj, projections which support the boxes of the intermediate geer shaft k, the
cranks of wrought-iron.
H, shaft which can be moved endwise, on which are the two pinions II'; l, a clutch which holds the
shaft H in either of three positions m, a rod connecting the two frames or sides G.
Operation.-When small weights are to be raised, the pinion I' is thrown into geer with L; on the
extremity of its shaft M the pinion N works in the geer o, on the same shaft P with the barrel Q.
on which is wound the chain r, which, passing over the rollers R and the pulley S, is attached at its
other extremity to the weight to be raised. Figs. 1832 and 1836.
But if the weight is considerable, the pinion I is thrown into gear with J, on whose shaft K is a
pinion q, geering into L.
The break consists of two curved strips of wrought-iron 00, connected by a hinge encircling the
pulley n, (on the shaft K,) and brought into more or less contact with it by the lever p, to the arms of
which the other extremities of the metallic strips o o are attached.
FREEZING APPARATUS. An experiment of freezing water in vacuo, by its own evaporation,
Fig. 1845, is shown by a shallow glass vessel, as a watch-glass, for containing the water to be frozen,
which is supported over a wide glass basin. containing strong sulphuric acid, the whole covered by a
low receiver. When the air is exhausted from the receiver, the acid will absorb the vapor from the
water as rapidly as it is found, thereby abstracting the sensible heat from the water, till congelation
ensues.
1845.
This is a mere matter of experiment, but within the last year an invention has
been patented by which ice can be manufactured mechanically in large quanti-
ties, and it is supposed economically in low northern and southern latitudes. But
it has not yet been sufficiently tested. It consists essentially of a force-pump, in
which air is divested of its latent heat by mechanical compression, and an engine
in which the same air is made to act expansively, and in the process to absorb
from the water to be frozen the heat due to its increase of volume. But there are several auxiliary
agents for giving this simple contrivance its greatest effective utility. Thus by an obvious arrange-
ment of attaching the pump and engine to the opposite ends of a common beam, the power consumed
in condensing air in the pump is, to a considerable degree, recovered in its expansion in the engine. At
the same time the heat evolved by the compression of the air is extinguished by a jet of water thrown
into the body of the force-pump by means of a smaller pump; while the heat necessary to impart to
the expanding air the elasticity and mechanical force due to its volume is furnished through a similar
pump, which takes from the cistern a portion of the liquid, and after injecting it into the expanding air
in the engine, returns it to the same cistern. The cistern thus operates as a reservoir of cold, and as
the sufficient means of abstracting heat from water which is to be converted into ice. It is proposed to
use the same air over and over again and thus the inventor attains the object of employing air which
previous condensation has deprived of heat, and subsequent expansion has left at a lower temperature
than the atmosphere.
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FRICTION.
705
FRICTION.-Friction is the resistance occasioned to the motion of a body, when pressed upon the
surface of another body, which does not partake of its motion. Under these circumstances, the surfaces
in contact have a certain tendency to adhere. Not being perfectly smooth, the imperceptible asperities
which may be supposed to exist on all surfaces, however highly polished, become to some extent inter-
locked, and in consequence a certain amount of force is requisite to overcome the mutual resistance to
motion of the two surfaces, and to maintain the sliding motion, even when it has been produced. By
increasing the pressure, the resistance to motion is increased also; and on the other hand, by rendering
the surfaces more smooth, and by lubrication, its amount is greatly diminished, but can never be en-
tirely nulled.
Friction ought not strictly to be called a force, unless that term be in this case taken in a negative
sense. The tendency of force, in the rigid meaning of the word, is to produce motion, whereas the
tendency of friction is to destroy motion. An active force may indeed oppose motion in one direction,
but only in virtue of a tendency to produce motion in the opposite direction; the peculiar characteristic
of friction, on the other hand, is that it tends to destroy motion in every direction. It is essentially a
passive resistance, a negative force, produced by pressure, to which it bears such relation that its
amount may be measured by the same unit and enunciated in the same terms.
Nor is the measure of the friction between two surfaces in contact, properly the amount of force
necessary to produce motion; but the amount of pressure necessary to balance the friction, and bring
the body to a state of indifference to rest or motion. To understand this, let us suppose that a heavy
hemispherical body rests with its flat surface upon a horizontal plane, and that the plane and the body
are perfectly smooth: on this supposition there would be no friction, and the smallest possible force
would put the body in motion. This condition being remarked, let us suppose that the surfaces in con-
tact are of the ordinary kind, and that a weight of 10 lbs. attached to the movable body and made to act
in the direction of the plane, is found to induce the same state of indifference to rest and motion as in
the assumed case of no friction; we then conclude that 10 lbs. is the measure of the friction. As it is
not always easy to determine when this condition is induced, it is better to regard the weight as an
active force, which may, by addition, be made more and more intense, till motion of the body is actually
induced. For the sake of convenience we may also speak of friction as a force and oppose it to other
force : this can induce no erroneous conclusion.
Friction being then considered a passive force, its effect is the result of having other force to resist.
If the measure of the friction of a body upon a plane be 10 lbs., and if an increasing force of 1, 2, 3 lbs,
and 80 on, be applied, the friction increases with the force till the limit is reached; motion then ensues
by the addition of any fraction of weight to the 10 lbs. The force of friction, although tending to pre-
vent or destroy motion, may also be conceived to act like other force,
in a direction opposite to that in which the balancing force acts: that
A
B
is, in the language of mechanics, if the force P, applied to balance the
friction F, act in the direction A B, the friction F acts in the direction B A. If then the body placed
upon the horizontal plane, as supposed, be capable of motion in the two directions A B and BA, the
body will remain at rest when acted upon by any force up to 10 lbs. in either of the directions. If
therefore we distinguish the forces acting in opposite directions by the positive and negative symbols +
and -, then the limits of equilibrium will be expressed by P = ± 10 lbs., according to the usual mode
of representing an equilibrium of forces.
What is here stated in reference to a heavy body placed upon a horizontal plane, is equally true of
the rubbing parts of every machine; the pressure upon the journals, by instituting resistance to motion,
that is, friction, the equilibrium will subsist between certain limits, and it is only by transgre-sion of
those limits on one side, that the equilibrium is destroyed and motion established. To determine accu-
rately those limits in machines, is one of the most important problems in mechanics; and it has only
been by the elaborate and admirably conducted experiments of the French Academy, that a sufficiently
extensive code of data has been attained possessing the requisite evidence of accuracy, to warrant im-
plicit confidence in the truth of the following important laws, which include the whole doctrine of fric-
tion as a retarding force in the dynamical operation of machines.
LAW L- The friction bears to the pressure upon the surfaces in contact, a ratio which is constant for
the same materials with the same condition of surfaces.
To express this somewhat more familiarly: If the surface of one body be pressed upon that of
another, with a certain force, and if that force be doubled, the friction will be doubled; and if the force
pressing them together be tripled, the friction will be tripled; and so on. Thus if a piece of cast-iron
weighing 100 lbs. be laid with its plane surface upon a larger surface of brass, level, and it be found
that a certain weight made to act in the direction of the supporting plane, is just sufficient to induce in
the mass of iron a state of indifference to rest or motion, that weight is the measure of the friction be-
tween the two surfaces; and if these be well polished and clean, and without lubricant of any kind, the
weight which it will be necessary to apply will be 14.7 lbs. If now we place a weight of 100 lbs. upon
the mass of cast-iron, making the gross pressure upon the surfaces in contact 200 lbs,, the weight neces-
sary to balance the friction will be increased in the same ratio, that is F = 14-7 lbs. X 2 = 29 lbs.
Another weight of 100 lbs.. placed on the first, making the pressure 300 lbs., will increase the measure of
friction to 14-7 lbs. X 3 = 44.1 lbs. And 80 on for every increment of pressure as expressed by the law.
If now we divide the weight which balances the friction, by the weight which measures the pressure
upon the surfaces, we obtain a ratio which is manifestly constant, since the pressures upon the surfaces
and the weights balancing the friction, corresponding to those pressures, are respectively multiples
throughout, of the first units 100 lbs. and 14-7 lbs. Thus we have
14.7
lbs.
294
lbs.
44.1
lbs.
100
lbs.
200
lbs.
300
lbs.
From this then it appears, that knowing the measure of the friction for a given unit of pressure upon
89
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FRICTION.
the surfaces in contact, these remaining constant in kind and condition, the measure of the friction an-
swering to any other pressure may be deduced. In the case assumed we have a common ratio of .147
between the pressures of contact, and the measures of the friction; this ratio therefore being known,
together with the pressure in the particular case, the measure of the friction for that case will also be
known. Putting P = the pressure upon the rubbing surfaces; F = the measure of the friction;
and f=ₚ; then we have F=fxP.
In this formula the ratio f of the friction to the pressure is termed the coefficient of friction. Its
value, as already announced, is constant for the same materials and condition of the surfaces in con-
tact; but varies as these vary. Thus in the particular case taken, the value is .147; but if the rubbing
surfaces be unctuous, it is reduced to 132; that is, by repetition of the experiments described above,
with this new condition of surfaces, we should find
132 X 100 lbs. = 132 lbs.
=
=
-132
X
200
lbs.
=
26'4
lbs.
}
measures
of
the
friction.
=
= 132 X 300 lbs. = 396 lbs.
If a cast-iron plate be substituted for the brass plate used as the supporting surface, and the surfaces
be first well polished, clean, and dry, next wetted with water, and lastly, be freely lubricated with hogs'
lard, we have the three values = 314, answering to these conditions; hence taking
P as before, we have by substitution in the formula F=fxP, the following results:
Surfaces wet.
Surfaces dry.
Surfaces lubricated.
For 100 lbs.
F = 15.2 lbs.
F 31·4 lbs.
lbs.
200 lbs.
F = 304 lbs.
628 lbs.
= 14 lbs.
300 lbs.
F = 45-6 lbs.
F 932 lbs.
F 21 lbs.
The determination of f, that is, of the coefficient of friction, for different kinds of materials, and also
for different states of their surfaces in contact, is manifestly the business of experiment. There is no
a priori rule by which it can be arrived at in the present state of our knowledge of the physical prop-
erties of bodies.
1846.
There is another mode of considering the subject
here discussed, which has its expression likewise
in the subjoined table, and which it becomes us
therefore to explain.-Let us suppose the arrange-
P
ment as in the experiments described, and that AB,
Fig. 1846, is the supporting surface, and C the mass
of cast-iron resting upon it. Again, let the pressure
of the mass acting perpendicularly to the surfaces
in contact, be denoted by P, and let the force Q,
parallel to the surfaces, be applied to slide the
c
body towards A. Then since the forces P and Q
a
F
act in directions perpendicular to one another, B
A
they manifestly cannot counteract one another;
consequently, were there no third force F opposed to Q. the system would be unbalanced, and there
would obviously be motion of the mass C in the direction of the second force. The third force F is the
friction, and so long as the force Q does not exceed its limit, the system must remain stable.
This being understood, let us suppose that the force P, Figs. 1847 and 1848, instead of having its direction
perpendicular to the surfaces in contact, is impressed obliquely; if then the parallelogram of forces P' Q be
completed, the force P, represented by the line M, is equivalent to two others represented by P'M, by
which the surfaces are pressed together,
and Q M which tends to give motion to
A
the body in a direction parallel to the sur- B
1847.
B
1848.
faces. Now the actual friction F of the "P
surfaces must be a certain fraction of
P
P
P
PM; let it be MQ'=MF and complete
P
P
the parallelogram P'Q', and draw its
diagonal P"M. Since then repre-
sents the friction of the body upon the
plane, that is, the resistance called into
action by the force PM, and since Q M
represents the whole tendency of PM to
produce motion of the body, it follows
that the body will move or not according
as QM is greater or less than Q'M, that
is, as PP' is greater or less than P"P',
or as the angle PMA is greater or less
than the angle BMA. These conditions
Q
d)
M
are shown in the diagrams: in the first
F
É
a
M
F
there would be motion induced by the preponderance of force QQ'; in the second, the friction F =
MQ' being greater than QM, the system would remain at rest.
The angle BMA is termed the limiting angle of resistance, or more shortly the angle of friction.
Its tangent is the fraction which is the coefficient of friction. The angle is manifestly
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FRICTION.
707
the same for surfaces of the same nature, whatever be the actual amount of the impressed force P; but
is different for different surfaces.
From this then it appears that the force impressed upon the surface of a solid body, at rest, by the
intervention of another solid body, will be destroyed, whatever be its direction, provided only the angle,
which the direction makes with the perpendicular to the surface, do not exceed the angle of friction of
that surface; and that this is true, however great the force may be. Also that if the direction of the
force lie without this angle, it cannot be sustained by the resistance of the surfaces in contact; and that
this is true, however small the force may be.
This beautiful principle of the angle of friction was first examined by the celebrated mathematician
Euler. His mode of demonstration was different, and in some respects, more obvious; it consisted in
showing at what angle of inclination a body would begin to slide down an inclined plane. By similar
reasoning to that employed above, it is readily determined that the body will just be sustained on the
inclined plane, without slipping, when the inclination of the plane is equal to the limiting angle of re-
sistance; and the tangent to the angle of inclination is the ratio of the friction to the pressure. Know-
ing therefore this angle the coefficient of friction is known, and conversely, the coefficient being known
the inclination is likewise known.
LAW II-The measure of friction is independent of the extent of surface, the pressure and the condi-
tion and character of the surfaces remaining the same.
This important property of friction was also first announced by Amontons; and finally established
by M. Morin, who found it to hold good, even at pressures so great that the surfaces were considerably
abraded. It might, in fact, be inferred from the law previously explained, to which it is nothing more
than a corollary; for by increasing the surface which supports the pressure, the amount of pressure
upon every point of the surface is diminished and although there are more rubbing points, their aggre-
gate amount of friction must of necessity be the same as before. It can readily, however, be conceived
that there will be a limitation to the proposition, when the rubbing surface is 80 small in proportion to
the pressure, that abrasion of the surfaces ensues to an immoderate extent, (as in the operations of cut-
ting and hewing, which are not contemplated in the enunciation;) but if the surface is sufficient to ren-
der the cutting and wearing, and also the heating, imperceptible, then the friction is as the pressure,
and independent of the extent of the surfaces.
LAW III-The friction is entirely independent of the velocity of continuous motion.
This fact results from the experiments of M. Morin; but it must not be supposed that it implies that
the same amount of mechanical power is expended in overcoming friction at all velocities of motion.
On the contrary, the law implies that the amount of mechanical power expended in overcoming the
friction, is proportionate to the velocity of the motion, since a constant force must be exerted with a
varying velocity. For instance, whatever amount of mechanical power may be lost by the friction of
the parts of any machine, while moving with a given velocity, (supposing the pressure on the rubbing
parts to remain constant,) a double power will be lost by friction when the machine moves with a dou-
ble velocity and 80 on in proportion. It also follows that the amount of mechanical power lost by
friction will, in all cases, be proportionate to the space passed over by the surfaces in contact without
regard to time; for instance, the amount of mechanical power, which must be expended to move a car-
riage for a given distance along a level railway, will be the same whether it travels quickly or slowly
over that distance. The friction is, in short, a uniformly retarding force, and is always the same
fraction of the pressure, however great, (within certain limits,) and however small that pressure
may be.
From the preceding discussion, it then appears that the whole doctrine of friction may be reduced to
the single proposition that the friction is proportionate to the pressure upon the surfaces in contact, and
independent of the extent of these surfaces, and of the velocity of their motion. There is still, however,
to be noted the extreme case of no velocity after the two surfaces have remained for a considerable
time in contact. If a body be laid upon an inclined plane, and the angle of this be very slowly increased,
the body will not begin to slide down when the inclination is exactly equal to the angle of friction.
This condition of quiescent friction was also investigated by M. Morin, and a summary of the results
which he obtained will be found in the subjoined table. It must, however, be observed that this species
of friction does not only differ in its amount from the friction of surfaces in continuous motion, but like-
wise in its nature, especially in this, that the friction of quiescence is subject to causes of variation and
uncertainty from which the friction of motion is exempt. Nor does the variation appear to depend upon
the extent of the surfaces of contact; for with different pressures, the ratio of the friction to the pres-
sure, that is, the coefficient of friction, varied greatly, although the surfaces in contact remained the
same. This uncertainty appears at first to complicate the whole question; but fortunately the difficulty
is removed by a second very important fact developed accidentally in the course of the experiments;
namely, that by the slightest jar or shock, even the most imperceptible movement of the surfaces of con-
tact, the friction is made to pass from a state accompanying quiescence to that entirely different state
of friction which accompanies motion, and as every machine, of whatever kind, may be considered
subject to such shocks, it is evident that the state of friction to be made the basis on which all questions
of statics are to be determined, should be that which accompanies continuous motion, the laws of which
are uniform and precise.
The actual measure of the friction of two rubbing surfaces for a given pressure, must obviously de-
pend upon the hardness and smoothness of the surfaces, as upon these depend the extent of the mutual
penetration and interlocking of the insensible asperities. It was also supposed to be established by the
experiments of Coulomb, that the friction between similar substances is greater than between substances
which are dissimilar; but this conclusion, although it has been long received as a general law of fric-
tion, is not sanctioned by the investigations of M. Morin, which are in every respect more worthy of
confidence than those upon which the assumption is based.
When lubrication is employed to lessen the friction, a distinction is to be made between the case in
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FRICTION.
which the surfaces are simply unctuous and in intimate contact, and the case in which the surfaces are
wholly separated from one another by an interposed stratum of the unguent. If the pressure upon the
surfaces of contact of given dimensious be increased beyond a certain limit, the latter of these cases
passes into the first; the stratum of unguent being pressed out, and the unctuous surfaces which it
separated from one another being brought into intimate contact. As long as either of these two states
romains, the laws of its friction are not affected by the pressure of the unguent; but in the transition
from the one state to the other, an exception is made to the independence of the friction upon the extent
of the surfaces of contact for supposing the extent of two surfaces of contact between which a stratum
of unguent is interposed, and which sustains a given pressure, to be continually diminished, it is evident
that the portions of this pressure which take effect upon each element of the surfaces of contact will be
continually increased, and that they may thus be so increased, as to press out the interposed stratum
of unguent, and cause the state of the surfaces to pass into that designated as unctuous, thereby chang-
ing the coefficient of friction. The second law of friction then, which is known as the law of the in-
dependence of the surface," is to be received in the case where a stratum of unguent is interposed,
within certain limits.
The observation made by M. Morin, that whenever two perfectly clean surfaces were made to move
upon one another, both were worn into alternate ridges and channels, accompanied by the formation of
a powder, is not without its practical value. During the experiments this effect was invariably pro-
duced whenever the pressures were very great, and was commonly attended in the experiments upon
the friction of woods. with the odor of burning wood. The effect was also found to be very considera-
ble in the case of fibrous metals, such as wrought-iron, sliding upon each other; less in the case of
granular metals, such as cast-iron, sliding upon the fibrous; and least of all when the granular metals
were slid upon one another.
This was found not to be the case when the surfaces of contact were unctuous, and the circumstance
suggested to M. Morin what appears to be a true explanation of the remarkable difference between his
results and those of Coulomb. He conceives that in the experiments of that celebrated engineer, the
requisite precautions had not been taken to avoid unctuosity-such as might present itself accidentally
in polishing the surfaces. In that case abrasion would be prevented, and instead of a new surface being
continually presented by wear, the same surface would remain, and receive by the motion continually a
more perfect polish.
Rolling friction.-The theory of rolling friction is by no means firmly grounded. We know that it
increases with the pressure. and that it is greater for a smaller than for a larger diameter of the rolling
body; but in what algebraical dependence this friction stands to the pressure and diameter of the
rolling body, cannot as yet be considered as determined. Coulomb made only a few experiments with
rollers, from two to twelve inches thick, of lignum-vite and elm, which were rolled along a surface of
oak, by means of a thin thread passing over a roller whose extremities were stretched by unequal
weights. From the results of these experiments, rolling friction appears to increase directly with the
pressure and inversely with the diameter of the roller, 80 that the force necessary to overcome
this friction may be expressed by F=/R, if R be the pressure, r the radius of the roller, and f the
coefficient of f.iction derived from experiment. If r be given in inches, then from these experiments,
for rolling upon compressed wood, if the wood be These formulas suppose
that the force F acts at the circumference of the roller, but if the force be applied to the axis of the
rolling bodies, by which, as in every description of carriage, axle friction ensues, the required force is
F, because here the arm is only half that of the diameter with respect to the point of application.
Explanation of the tables.-The first and most extensive of the following tables, contains a very
complete summary of M. Morin's experiments of the friction of plane surfaces sliding upon another. It
embraces the three conditions of clean and unctuous surfaces, and surfaces between which a stratum of
the lubricant is interposed. The coefficient of friction is given for each of those conditions for both the
friction of motion and the friction of quiescence, and also the limiting angle of resistance answering to
the coefficients of friction in the cases of clean and unctuous surfaces. The sliding surfaces were varied
from 03336 to 2.7987 square feet, and the pressures from 88 lbs. to 2205 lbs. The surfaces of the
woods were planed, and those of metal filed and polished with the utmost care; and when the friction
of the clean surfaces was to be determined, any unctuosity was especially guarded against. In the
experiments upon unctuous surfaces, the unguent was carefully wiped off, 80 that no interposing layer
of it should prevent their intimate contact. In the experiments to determine the friction with unguents
interposed, the extent of the surfaces bore such a relation to the pressure, that a stratum of the lubri-
cant was retained between them. The relations kept in view were such as are commonly found in the
larger class of machines in which the adhesion of the lubricant to the surfaces of contact may, as re-
spects opposition to motion caused by its viscidity, be overlooked as altogether insignificant compared
with the friction. As respects the nature of the substance used in lubrication, it will be observed by
comparison of the coefficient of the friction of motion, that with hog's lard and olive oil, surfaces of
wood on metal, wood on wood, metal on wood, and metal on metal, have all very nearly the same fric-
tion, the value of the coefficient being in all those cases included between 0.07 and 0-08. With tallow
the coefficient is the same except in the case of metals upon metals; this lubricant seems therefore
less suited for metallic surfaces than the others named.
The second table contains the results of experiments upon the friction of axles of different materials
upon their bearings. It requires no further explanation, but attention may be directed to the advan-
tage to be derived from attention to the mode in which the lubricating substance is applied.
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FRICTION.
709
SUMMARY OF M. MORIN'S EXPERIMENTS OF THE FRICTION OF PLANE SURFACES.
Friction of
Friction of
motion.
quiescence.
SLIDING
SURFACE
Limit-
Limit-
STATE OF THE SURFACES.
SURFACE.
Co-effi
ing an. an-
Co-effi.
AT REST.
ing an-
cient of
gie of
cient of
gle of
friction.
resist.
friction.
resist-
nuce.
ance.
Without lubrication
0.478
25.33'
0-625
39. 1
Oak
Oak
Direction of fibres parallel to
tallow
0.975
0-160
the motion
Lubricated with
lard
0.067
Without lubrication
0.324
17 58
0.540
28 23
Uncinous
0.143
8 9
0-314
17 96
do
do
Fibres of the moving surface
tallow
0.083
0-254
perpendicular to the motion.
Lubricated with
lard
0.072
water
0.250
Fibres of both surfaces perpen-
do
do
dicular to the direction of the
Without lubrication
0.336
18 35
motion
Fibres of the moving surface
do
perpendicular to the surface of
do
contact, and those of the qui-
Without lubrication
0.192
10 52
0.271
15 10
eacent surface parallel to the
motion
do
do
Fibres of both surfaces perpen-
dicular to the surface of con-
Without lubrication
0.43
23 17
tact, or the pieces end to end
Without lubrication
0.246
13 50
0.376
20 37
Unctuous
0.136
7 45
Oak
Elm
Fibres parallel to the motion
dry soap
0.136
Lubricated with
tallow
0-073
0.178
lard
0.066
Without lubrication
0.432
23 92
0.694
34 46
Unctuous
0-119
6 48
0.420
22 47
Fibres parallel to the motion
dry soap
0.137
0.411
Elm
Oak
Lubricated with
tallow
0.070
0.142
lard
0.060
Fibres of the moving surface
Without lubrication
0.450
24 16
0.570
29 41
perpendicular to the motion
Without lubrication
0.360
19 48
0-530
27 56
Beech
Oak
Fibres of both surfaces parallel
Unctuous
0.330
18 16
to the motion
Lubricated with tallow
0.550
Ash and Sor-
Without lubrication
0.400
21 49
0.570
29 41
rel wood
do
do
0.355
19 33
0.590
27 29
Fir
Oak
Fibres of both surfaces parallel
do
do
0.370
20 19
0.440
23 45
Pear-tree
to the motion.
do
do
0.619
31 47
0.619
31 47
Wrought-iron
Cast-iron
Lubricated with
dry soap
0.214
tallow
0.085
0.108
Tallow
0.098
Greased and saturated with
water
0.256
0.649
Oak
Wrought-iron
Without lubrication
0.252
14 9
Elm
Elm
do
do
Unctuous
0.138
7 52
Wrought-Iron
do
tallow
0.078
Lubricated with
lard
0.076
olive oil
0.055
Without lubrication
0.490
26 7
Unctuous
0.107
6 7
0.100
5 43
dry soap
0.189
tallow
0.078
0.100
Cast-iron
Oak
do
do.
Lubricated with
lard or
olive oil
0.075
0.100
Greased and saturated with
water
0.218
0-646
Fibres of the wood parallel to
Lubricated with tallow
0.80
Oak
Cast-iron
the motion
do
do. perpedicular
Without lubrication
0.372
20 25
to the motion
do
do.
0-195
11 3
tal-
Surface unctuous with
low
0.125
7 8
Cast-iron
Elro
do
do. parallel to
lard
0.137
7 49
the motion.
tallow
0.077
Lubricated with
lard
0.091
olive oil.
0.061
Surfaces unctuous
0.135
7 42
0.098
5 36
do. lubricated with tallow
0.066
Elm
Cast-iron
Without lubrication
0.394
21 31
Hornbeam
do.
Pear-tree
do.
do
do
do
do.
0.436
23 34
do
do.
0.617
31 41
0.617
31 41
Copper
Oak
Surfaces unctuous
0.100
5 43
Lubricated with tallow
0.069
0.100
Without lubrication
0.138
7 52
0.137
7 40
Surfaces unctuous
0.177
10 3
Wrought-iron
Wrought-irom
Fibres of both surfaces par-
tallow
0.082
allel to the motion
Lubricated with
lard
0.081
olive oil
0.070
0.115
Without lubrication
0.194
10 59
0.194
10 50
Surfaces unetuous
0.118
6 44
Wrought-iron
Cast-iron
do
do
tallow
0.103
Lubricated with
lard
0.076
olive oil
0.066
0-100
5 43
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FRICTION.
SUMMARY OF M. MORIN'S EXPERIMENTS OF THE FRICTION OF PLANE SURFACES.-(Continued.)
Friction of
Friction of
motion.
quieecence.
SLIDING
SURFACE
Limit-
Limit.
STATE OF THE SURFACES.
Co-effi.
ing an-
Co-effi-
ing an-
SURFACE.
AT REST.
cient of
gle of
cient of
gie of
friction.
restal.
friction.
resist.
ance.
ance.
Surfaces unctuous
0.143
8' 9'
Cast-iron
Wrought-iron
Fibres of both surfaces par-
Lubricated with tallow
0.100
5.43'
allel to the motion
Without lubrication
0.152
8 39
0.162
9 13
Surfaces unctuous
0.144
8 12
water
0-314
soap
0.197
tallow
0.100
5 43
0.100
5 43
Cast-iron
Cast-iron
do
do
Lubricated with
lard
0.070
0.100
olive oil.
0.064
lard and
pl'bago.
0.055
Without lubrication
0.172
9 46
Surfaces unctuous
0.160
9 6
Wrought-iron
Bronze
Fibres parallel to motion
tallow
0.103
Lubricated with
lard
0.075
olive all.
0-078
Without lubrication
0.161
9 9
Surfaces unctuous
0.166
9 26
tallow
0.081
Bronze
Wrought-iron
do
do
Lubricated with
lard and
pl'bago.
0.089
olive oil.
0.072
Without lubrication
0.147
8 22
Surfaces unctuous
0.132
7 98
Cast-iron
Bronze
do
do
tallow
0.103
Lubricated with
lard
0.075
olive oil.
0.078
Without lubrication
0-217
12 15
Surfaces uncluous
0.107
6 7
Bronze
Cast-iron
do
do.
tallow
0.086
0-106
Lubricated with
olive oil
0.077
Without lubrication
0.201
11 22
Bronze
Bronze
do
do.
Surfaces unctuous
0.134
7 38
0.164
9 19
Lubricated with olive oil
0.058
Without lubrication
0.189
10 49
Surfaces unctuous
0-115
6 34
Brass
Cast-iron
do
do.
tallow
0.072
0.103
Lubricated with
lard
0.068
olive oil
0.066
Without lubrication
0.202
11 26
Steel
tallow
0.105
0-108
Cast-iron
do
do
Lubricated with
lard
0.081
olive oil
0.079
Lubricated with
tallow
0.093
lard
0.076
Steel
Wrought-iron
Fibres of iron parallel to the
Without lubrication
0.152
8 39
Steel
tallow
0.056
Bronze
motion
olive oil
0.053
Lubricated with
lard and
pl'bago.
0.067
Fibres of the oak parallel
Black leather
Without lubrication
0.265
14 51
0.74
3631
leather laid flat
(as used for
Oak
do.
polished and
light straps)
hardened by
do
do
0.296
16 30
hammering
Ox hide (such
0.52
27 29
0.605
31 11
as used for
Without lubrication
do
rough
0.335
18 31
0.43
23 17
strong belts
Fibresof woodparallel
smooth
Leather saturated with
&c.)
water
0.29
0.79
Surface unctuous
0.229
12 54
0.267
14 57
Greased and saturated with
do
Cast-iron
do
do
water
0.365
Lubricated with
tallow
0.159
olive oil.
0.133
0.122
Surfaces unctuous
0.244
13 43
do
Brass
do
do
tallow
0.241
Lubricated with
olive oil.
0.191
Fibres of hemp not twisted and
placed in a direction perpen-
Hemp
Oak
dicular to those of the motion
Greased and saturated with
fibres of the oak parallel to the
water
0.338
0.889
motion
Hemp
Cast-iron
Fibres of hemp, as above
Hemp-twist
Cast-iron
do
tallow
do.
0.194
Lubricated with
olive oil.
0.153
Fibres of the wood and direction
Hemp-band
Oak
of the cord parallel to the mo-
Without lubrication
0.52
27 29
0.64
22 38
tion
Hemp plait
band ofsmall
do
do
do
do
do
0.28
17 45
0.50
26 34
cords
Old cordage
If in. diam
do
do
do
do
do
0.58
27 29
0.79
38 19
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FRICTION ROLLERS.
711
RATIOS OF FRICTION TO PRESSURE FOR AXLES IN MOTION IN THEIR BEARINGS.
I.-ACCORDING TO MORIN'S EXPERIMENT.
State of Surfaces and nature of Lubrication.
Designation of surfaces
Oil, tallow, or hogs' lard.
Dry
Greasy,
Lubricated,
Purified
Hogs' lard
Greasy,
in contact.
or slightly
and wet with
and wet with
Supplied in
The grease
very soft
with
very soft to
greasy.
water.
water.
the ordinary
continually
grease.
plumbago.
the touch.
manner
renewed.
Bronze on bronze
0.079
do. on cast-iron
0.049
Iron on bronze
0.251
0.189
-075
0.054
0.000
0·111
do. on cast-iron
.075
0.054
Oast-iron on cast-iron
0.137
0.079
.075
0.054
do. on bronze
0.194
0·161
0.075
0.054
0.065
0.137
Iron on lignum-vite
0.188
0.125
0.166
Cast-iron on do
0-185
0.100
0.92
0.109
0.140
Lignum-vite on cast-iron
0-116
0-153
do.
on lignum-vitse.
0.170
IL-ACCORDING TO COULOMB'S EXPERIMENT.
Dry.
Olive-oil.
Hogs' lard.
Tallow.
Greasy.
Old
lubrication.
Observations.
Iron on copper
0-155
0·130
0.120
0.085
0.127
0-133
The number relative to
Iron on wood
0.050
the friction of iron on
Green-oak on lignum-vite
0.060
wood is deduced from a
0.038
0-070
pulley. the lubrication of
do. on elm
0.030
0-050
which, or the nature of the
Box on lignum-vitse
0.043
0.070
axis and bearings, are not
Box on elm
0.035
0.050
mentioned by Coulomb.
FRICTION ROLLERS. The obstruction which a cylinder meets in rolling along a smooth plane is
quite distinct in its character, and far inferior in its amount to that which is produced by the friction of
the same cylinder drawn lengthwise along a plane. For example, in the case of wood rolling on wood,
the resistance is to the pressure, if the cylinder be small, as 16 or 18 to 1000; and if the cylinder be
large, this may be reduced to 6 to 1000. The friction from sliding, in the same cases, would be to the
pressure as 2 to 10, or 3 to 10, according to the nature of the wood. Hence, by causing one body to
roll on another, the resistance is diminished from 12 to 20 times. It is therefore a principle in the
composition of machines that attrition should be avoided as much as possible, and rolling motions sub-
stituted whenever circumstances admit.
On this principle depends the advantages resulting from the application
1819.
of friction wheels and friction rollers. The extremity of an axle C, instead
of resting in a cylindrical socket, is made to rest on the circumferences of two
wheels, A and B, to the axles of which, a and b, the friction is transferred,
and consequently diminished in the ratio of the radius of the wheel A to the
B
radius of the axle a. This ingenious contrivance appears to have first been
applied by M. Sulley, in the year 1716.-Descr. Abrigée d'une Horoge, &o.,
Bordeaux, 1716.
The following are deductions from Coulomb's experiments relative to the
friction of rolling bodies: 1. Like the friction of sliding bodies, it is a con-
stant force. 2. It is affected by the nature of the surface 80 far as polish is
concerned; but is not lessened by the interposition of unctuous substances.
8. It is less between heterogeneous than between homogeneous substances. 4. It is directly propor-
tional to the pressure. 5. It has no relation to the magnitude of the surface. 6. It is much less than
in the case of sliding surfaces, and varies in the inverse ratio of the diameter of the rolling body.
The friction of the axle of a wheel or pulley (whether the axle itself turns, or the wheel turns on the
axle) is of a different kind from that of a cylinder rolling on a plane. It is less than that of sliding but
greater than that of rolling bodies, and follows in all respects the laws of the friction of sliding bodies.
A great advantage is here obtained by greasing the surfaces. By the application of fresh tallow the
friction is reduced to one half.
Friction is one of the most effectual means of arresting motion. In some
1850.
machines, especially wind-mills, cranes, &c., it is very important to have the power
of suddenly stopping the machine, or at least of controlling its motion. This is
effected by means of a strong bridle of wood or iron, a b c, fixed at one end, and
at the other furnished with a lever, by pressing on which, the bridle is brought
into close contact with the broad rim of a wheel which participates in the general
motion of the machine. The bridle may be made to bear on the whole circum-
ference of the wheel; and a moderate pressure on the lever will produce a resist-
ance sufficient to destroy the motion almost instantaneously.
Coulomb's experiments were also directed to ascertain the resistance arising
from the rigidity of ropes when bent round rollers or cylinders. The results are
as follows 1. The resistance of ropes are directly proportional to the tensions to
which they are subjected. 2. The resistance increases with some determinate power of the diameter,
and is greatest in ropes that have been strongly twisted. or are coated with tar. 3. The resistances are
inversely as the diameters of the cylinders about which the ropes are bent.
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FRINGE MACHINE, SHAWL.
When a rope is wound more than once round a cylinder, the resistance increases in a geometrical
progression. This principle is frequently applied in practice: thus, in arresting the progress of a vessel,
a rope is wound round a post, and a very few turns is sufficient to overcome any force which the rope
is capable of withstanding.
FRINGE MACHINE, SHAWL, invented by Milton D. Whipple, and used at the Bay State Mills,
Lawrence, Mass., to twist the fringe of shawls, is a very successful, and as far as our knowledge extends,
the only machine which has ever been applied for this purpose. We extract from the patentee's spe-
cifications the following description of it and its operations:-
The machine is so constructed as to imitate and perform the ordinary manual operations of dividing
the yarns into proper quantities to form the two single strands, and then twisting the said strands
separately in one direction, and afterwards bringing together and twisting them in opposite directions
to form the fringe.
A'A'A'A' is the framework of the
machine. a a, a' a' is a stretching frame,
1851.
having a strip of card teeth bb, Fig. 1852,
on the stationary side of the frame, and a
set of vertical points on the sliding bar
a' a'. The yarn from which the fringe is
0
à
formed, having woven fabric on each side
as usual, is stretched from said card teeth
to said points, and the bar a' a' is arranged
и
0
so as to slide in and out to accommodate
t
different lengths of fringes. This stretch-
0
ing frame is moved, or fed along by means
of rack teeth formed on the under side of
the bar a a, as shown at c, Fig. 1851,
which engage with the teeth of a pinion
d, on the shaft e said pinion being
q
shown by dotted lines in Fig. 1852. This
shaft has one of its bearings on the top of
one side of the framework A'A'A'A',
as shown at Fig. 1852; its other bearing
being in a diagonal mortise g in the ad-
justable aliding bar hh, fitted in the op-
posite side of the framework, as shown
by dotted lines in Fig. 1852, and in detail
q
in Fig. 1854; 80 that by moving the said
sliding bar in one or the other direction,
the pinion may be thrown into or out of
geer with the rack, and permit the stretch-
ing frame to be moved backwards, after
twisting the fringe of one side of a shawl,
for a new operation. During the oper-
ation of twisting, this frame is fed along
accurately by means of a ratchet wheel i,
q
on the shaft 11, the teeth of which are
operated upon by the long pawl k, work-
ing on an eccentric l, fitted on the driving
shaft m m, as shown in Fig. 1852, and by
dotted lines in Fig. 1853.
The feed motion is regulated by means of the adjustable forked supporter n, in which the pawl k
rests, as shown in the drawings. By raising or lowering which supporter, the fall of the pawl k, when
it is drawn backwards on the ratchet wheel i, by the action of the eccentric l, will be diminished or
increased, as the case may be.
The machinery for dividing the yarns into proper quantities, to form the two single strands, as here-
inbefore suggested, is as follows :-0 are two metallic triangular dividing plates, set at a proper
interval apart on opposite sides of the elliptical ring pp, which ring is firmly fitted on the top of the
vertical sliding beam gg, Figs. 1852 and 1853, arranged so as to slide up and down in proper guides r,
as shown in the drawings. The plates 00 are curved transversely and vertically, 80 as to effectually
separate the yarns, and have a rectangular slot or opening formed through each, as shown at Fig. 1851,
for the passage of twisting fingers or rubbers, hereinafter described. The yarns embraced between
these plates 00 are subdivided or halved, for the purpose of forming two strands by means of the
separator tu, having the same triangular contour as the plates 00, so as to enter, as they do, between
the yarns at a mere point at first, and not get entangled with them. This separator is constructed in
two parts, with sufficient space cut out to allow the passage of the rubbers or twisting fingers before
referred to; both of said parts being connected to the top of the sliding beam VV, arranged side by
side with that before referred to, and denoted by q q. and moving up and down in the same guides.
One of said parts t of the separator is required to be fixed to said beam VV, and the other U is hinged,
as shown by dotted lines in Fig. 1851, so as to turn from it, when in descending, it comes against the
top of the upper twisting fingers;-the operation being similar to that of a pair of callipers or bent
compasses used for measuring the diameter of cylinders, &c.
After the yarns have been divided, as above described, into two parcels for the formation of two
strands, they are twisted by the curved twisting fingers or rubbers W X, which slide over each other,
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a
B
n
FRINGE MACHINE, SHAWL.
H
m
E
m
1852.
y
á
a
a'
a
&
06
E
d
c
a
I
f
I
I
l
714
FRINGE MACHINE, SHAWL.
y
:-
V
1853.
I
g
A.
a
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FULLING.
715
one above and the other below the yarns, as they pass through the openings in the dividing plates o o
and separator t u.
These twisting fingers or rubbers should be clothed with leather, or some other suitable substance,
sufficiently rough to turn and twist the yarns. They are connected to the ends to two arms a b¹, pro-
jecting out when the machine is stationary, about at right angles to each other, from the vertical shafts
c', d d', and arranged with set-screws so as to be adjustable thereon.
The vertical shafts have proper bearings in the framework, and are connected in their movements, so
as to turn together by the pinions e' f' arranged on them as shown in the drawings. Said shafts are
turned inwards, 80 as to bring the twisting fingers towards and over each other by the projecting stud g,
inserted in the shaft c' c', as shown in Fig. 1858, and abutting against the cam formed on the pulley h',
on the driving shaft, as shown in Fig. 1852. The outward or back turning of said shafts c' c', d'd' is
effected by the heavy counteracting weight i', connected to the shaft d' d, as shown in Fig. 1853.
When the rubber or twisting fingers are passing over each other, twisting the yarns into two strands,
the yarns are supported and lifted up in grooves in the upper side of flange pieces set on each side of
the two parts 1 u of the separator, as shown at k' k' k', &c., Fig. 1853, by dotted lines; and after the
two strands are sufficiently twisted, the separator tu is drawn downwards, opening over the rubbers or
twisting fingers in its descent; which descent is effected by the cam l' on the driving shaft m m, said
cam operating on the treadle m' m', the moving end of which is connected to the vertical sliding beam V v,
on which the separator is fastened as above suggested.
1854.
When the separator IS withdrawn after the two strands are twisted, as above explained, the rubbers
or twisting fingers are moved outwards by the action of the weight as above described,-twisting the
two strands together firmly, and forming the fringe as perfectly as it can be done by the most skilful
operative.
The two dividing plates o o are then withdrawn by a cam n' on the driving shaft, said cam operating
on the treadle o' o', and vertical sliding beam qq, on which said plates are fixed, in the same manner as
explained above, for the beam V V and cam and treadle by which it is operated. The stretching frame
is now fed along, and the cams ceasing to act upon the treadles, the retroacting springs p', p',
connected to the beams V V and qq, bring them, and with them the plates 0 and separator 26,
between the yarns for another operation.
While the yarns are being divided by the plates 00 and separator, it is absolutely essential that they
should be stretched transversely a little and held tight, in order to be easily divided, and that during
the operation of twisting, this stretching and holding should be gradually relaxed. This result is
attained by the long metallic hooked depresser and holder q' r', which moves up and down in proper
guides or mortises in the framework. The end r' of this depresser and holder falls on the yarn just
behind the plates o o and separator 26, and immediately after said yarns have been divided, and presses
them into a groove or bent plate formed at 8', Figs. 1852 and 1851, to receive them. This bent
depresser is operated by an arm t', which extends at right angles from one side of it, and rests on the
face of a proper cam, formed to regulate its motion on the pulley h', as shown by dotted lines in
Fig. 1853.
The patentee claims-First. Dividing the yarns into proper quantities for the formation of the two
strands, by means of the dividing plates and separator.
Second. Twisting the two strands separately first, and then together, by means of the twisting fingers
or rubbers, constructed and arranged 80 as to turn inwards and outwards over each other, one above and
the other below the yarns.
Third. The peculiar construction and arrangement of the separator, 80 that it may open over the
rubbers, and drop down just before the two strands are to be twisted together.
Fourth. A machine for twisting the fringes of shawls, &c., having a stretching frame, dividing plates,
and separator, twisting fingers or rubbers combined, and operated successively, as hereinbefore specified
and described.
1855.
FROG. The cast-iron crossing plate at the in-
tersection of two lines of rails on a railroad. The
intermediate point, being subject to great wear from
its small surface and exposed position, is usually
made of steel. This improvement was made the
o
subject of a patent in 1837.
FULCRUM, in mechanics, the prop, support, or fixed point upon which a lever is sustained; and
about which the lever is supposed to turn freely.
FULLING. A process by which woollen cloths are divested of the oil imbibed for the operation of
carding, and the texture is at the same time rendered much closer, firmer, and stronger. This process,
also called milling, was formerly entirely performed by the machine described under the head of Fall-
ing Stocks, also called fulling stocks, and fulling-mill. The stocks, although still in extensive use, are
fast being superseded by a superior class of machines, in which the cloth passes between squeezers, and
is not subjected to heavy b'ows. By these machines the pressure can be regulated according to the
quality and requirements .f the fabric. the milling is more perfect, the power expended is less, and,
not least, the disagreeable noise consequent on the use of stocks is avoided.
Figs. 1856, 1857, and 1858, represent different views of one of this class of machines. Fig. 1856 is a
side elevation, Fig. 1857 a cross section, and Fig. 1858 a front end elevation of the machine. It will be
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716
FULLING.
perceived that the machine is composed of four cylinders n n' ff' running horizontally, arranged in pairs
one above the other, and two vertical cylinders gg'. Both horizontal and vertical cylinders are sub-
jected to pressure: to the former it is applied by means of the weight movable on the arm of the
m
1856.
C
I
a
a'
9
9
d
A
A
0
6
a
A
1858.
1857.
t
a
5
o
D
a
(1)
8
e
n
D
0
n
0
0
D
0
o
A
a
a
lever C, which forces down the yoke k on the boxes of the cylinder. The pressure is applied to the
vertical cylinders by the variable weight 8, through the levers w. In both cases the pressure to be ex
erted can be varied at pleasure.
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FULLING.
717
The operation is as follows one end of the cloth having been passed between the sets of horizontal
and vertical cylinders, the two ends of the cloth are then attached together, 80 as to make an endless
band. The machine is now set in motion by the pulley e on the shaft b, and the cloth continues to
make the round between the cylinders or squeezers, falling in folds at the front of the machine, and
drawn up again at the back till the washing and fulling is finished.
A rotary fulling-mill, still better than the
1859.
preceding, is given in Figs. 1859 and 1860.
Fig. 1859 is the side elevation, and Fig.
1860 the longitudinal section, showing the
interior arrangement.
P
A A is the main cylinder, (driven by a
geer;) on either side are cheeks between
which the small cylinders or rolls B' B' B' re-
Bo
volve, and between these rolls and the cyl-
inder the cloth passes. C is the lower side
or bottom of a trough which receives the
K
cloth after it has passed the roll B', and
down which it slides into the tub d' d' d', L
curved, as shown in the drawings. D is the
top of the trough, and is supported by the
cross piece d; its upper extremity touches,
but without friction, the surface of the roll
B'. EE are the grooved sides of the trough;
their upper extremities are held by small
iron straps attached to the frame by screws,
and to EE by pins; the centre of the sides
are fastened to small iron plates F F, which
are supported on the standards G G, on which
they turn freely; the standards themselves,
attached to the plates HH, can turn on the
pivots IL
L is a cord attached to the ends of the levers KK, by which, through the aid of a pulley, the weight
M tends to draw them together. NN, a cross piece attached to the frame and supporting the pivots I,
and guide plates C'.
The journals 2, 3, 4, of the rolls B' Bª, run in bearings, inserted in the bars PPP, whose lower ex-
tremities are maintained in a position by the guide rings 8, attached to the frame, which admits of a
motion in the direction of their length; while at their upper extremities are racks into which play the
toothed segments ppp, fixed in pairs on the shafts n n n.
P' 'P'P', weights movable on the arms of the levers L' L', whose fulcra are at nn n. and attached
to the toothed segments P by these weights the force with which the rolls B' B' B' press on the
cylinder A is regulated. QQQ, guide rolls which keep the racks in geer with the segments.
R', a plate perforated with an oval hole, through which the cloth is first passed, the effect of which is
to straighten the folds; thence the cloth passes over a conducting roll S, through the short tube R, to the
main cylinder; the tube R is supported by a cross plate attached to the frame.
The draft or drawing in of the cloth is oc-
1860.
P
casioned by the pressure of the roll B' on the
P
main cylinder, which cylinders are geered
together by the pinion X' and the geer X,
on their respective shafts.
Operation of the machine.-The cloth is
first passed through the aperture R', over the
B
roll S, through the tube R, to the groove or
space between the cheeks of the main cylin-
der A, thence beneath the rolls B' B' B', and
is delivered through the trough CD E at the
N
back of the machine. The ends of the cloth
are now fastened together, the mill is set in
motion, and the operation is performed as in
the preceding machine. The cloth is pre-
sented successively in a continuous round to
the action of the squeezers till the fulling is
finished.
It will be easily perceived that the effect
of the passage of the cloth beneath the rolls
B' B² B' is a stretching of the cloth in the
direction of its length, which causes a thick-
ening or fulling of the cloth in the width.
The cloth should also undergo a compression
or fulling lengthwise. This is effected by the
sides E E of the trough CED; these sides hold by iron straps at their upper extremities, at a constant
distance, equal to that between the cheeks of the main cylinder, while their lower extremities, by means
of the pivots G G and II, admit of a lateral motion at these extremities. The weight M is made to act
through the levers K K, which brings them together, and prevents the discharge of the cloth; the result
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718
FULLING-MILL FOR CLOTH.
is that the cloth being still delivered by the roll B¹ is forced into the guide box till the pressure is suffi
cient to overcome that with which the two sides of the box are brought together by the weight M. The
sides of the box then take a nearly parallel position. The cloth escapes gently and falls into the cir-
cular box or tub, which composes the lower part of the machine.
As by the weights P'P' P' the pressure on the cylinders B' B²B' can be regulated, and consequently
the fulling breadthways of the cloth, so by varying the weight M more or less resistance can be opposed
to the discharge of the cloth, and by this means the fulling of the cloth lengthways can be increased or
diminished.
A system of percussion has also been added to this machine. Small revolving or reciprocating
beaters, making their blows on a fulling table, strike the cloth as it leaves the expanding trough.
These machines have long been used in England and on the continent. They are now manufactured
in this country, and where they have been adopted have given satisfaction.
FULLING-MILL FOR CLOTH. Fig. 1861 is a side elevation of the mill.
Fig. 1862 is an end elevation of the same.
The same parts are designated by the same letters of reference in both drawings
1861.
g
h
g
a
k
E
E
k
S
m
e
a
A
R
b
m
P
A
j
j
B
C
C
w
I
C
C
kk, the side framing of the machine, made of strong rectangular pieces of wood, connected together
at the top by the cross beams dd, the cross rails gg, upon which the four pieces hhhh rest in positions
parallel to dd, and at right angles to the rails g g. The use of the beams hhhh is, besides affording
additional stiffness to the framing, to carry the four pedestals ffff. in which are the working centres
of the feet, or beaters A A. These are suspended by the legs, or pieces EE From the under side of
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FULLING-MILL FOR CLOTH.
719
the feet, the lifters, or wipers BB project; and by means of these the feet are continually thrown back
by the two pairs of wipers CCCC, upon the common driving shaft I The upright framing is secured
at bottom by cross beams, into which the uprights k k are mortised; and these are bolted down usually
to a solid foundation of stone. R is the rowhead of the receptacle or trough into which the cloth to be
washed is put, and in which the beaters A A are suspended. The end R of this receptacle is formed
of two or more blocks of wood, commonly oak, firmly jointed together, and is shaped internally into a
parabolic curve, against which the cloth is pressed, by the beaters A A, alternately, during the opera-
tion of washing. By this means the cloth is continually, but slowly, being turned round by the action
of the beaters upon it. Water is meantime supplied from the cistern a, which extends across the back
of the framing, through a series of small holes pierced in the back of the trough R, and is let off through
holes pierced in the bottom of the same. The centre a is filled from a well or other reservoir, by the
pipe P.
1862.
h
h
h
h
g
d
d
0
O
lc
E
E
D
E
k
1863.
S
S
A
0
0
S
X
e
0
b
B
m
b
i
B
W
C
C
Y
I
C
C
The feet A A, as above described, are worked by the double wipers CCCC on the wiper shaft I;
these wipers being set pair and pair at right angles to each other, work the feet alternately; 80 that
when one foot is being caught by its wiper, the other is at that moment being released. The feet thus
rise and fall alternately, and make each two strokes during one revolution of the shaft I. Into the heel
of each foot is screwed a staple of iron m, which receives a hook-catch 8, jointed upon a lever, having
its centre of motion at the stud o. The use of this arrangement is to keep up the feet when the cloth
is being taken out of the trough. This lever and catch are represented separately by Fig. 1863.
The wiper shaft is usually connected to one of the main shafts of the works by a friction coupling of
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FURNACE.
some kind, for the purpose of starting the machine with as little shock as possible. An efficient and
simple coupling of this sort is, however, still a desideratum in practical mechanics.
In the machine from which these
drawings were made, the wipers are of
b
1864.
cast-iron This, however, is not to be
recommended, as the wipers are liable
to break by concussion with the lifters
if
a
B B; and, being cast pair and pair, in
one piece, they are difficult and costly
a
to replace. The most approved, and
now the most common mode, is to cast
strong centres which fit upon the shaft
I, and to attach to these malleable iron
1865.
wipers, which are not only less lia-
ble to fracture, but are also replaced
with more facility in cases of failure
from accident or decay. This arrange-
ment is represented by the annexed
wood-cuts, of which Fig. 1864 is an
C
elevation, and Fig. 1865 a plan of a
b
B
pair of the wipers. c, is the wiper
shaft, upon which the cast-iron centre
is keyer This centre is cast with two
flange pieces projecting in the plane of
I
the axis, and strengthened by feathers
on one side. These pieces are of the same breadth as the malleable iron arms ab, a b, which are to be
bolted to them at aa
FURNACE An enclosed fireplace for generating great quantities of heat. Furnaces are of various
forms, according to the purposes to which they are applied. In some cases it is intensity of heat that
is required, as in the furnaces for smelting, casting, and forging metals, for descriptions of which see
iron, metallurgy, &c. In other cases, a steady temperature is to be maintained, as in furnaces for the
generation of steam. The first object in the erection of a furnace is to procure a sufficient supply of air
for the support of the combustion of the fuel. In most of the former class of cases air is supplied by
blowers, fans, dic.; in the latter, more commonly, but not entirely, the draft is created by high stacks
of chimneys.
Flues-To determine the area of the flue and chimney, it must be considered that 15035 cubic feet
of air are required for the combustion of 1 lb. of coal. Of this air 44.64 feet combine with the gases
evolved from the coal, and 105-71 feet with the solid portion of the coal. The combination of the air
and gases increases their volume 1-10th. The 44.64 feet thus become 49104 feet. The sum of 105.35
with the carbon remains the same. The total product of the combustion (without considering the in-
crease of volume resulting from raising the temperature) of 1 lb. of coal. is therefore 105.71 + 49-104
= 154814 cubic feet. Assuming the temperature of the furnace at 1000° Fahr., at which aēriform
bodies are expanded to about three times their original bulk, the product will be 154814 X 3 = 464'442
feet. Adopting the result of Dr. Ure's experiments, viz. that the products of combustion pass off at a
velocity of 36 feet per second, the area to allow this quantity to pass off in an hour will be 516 square
inch. In a furnace in which 18 lbs. are burnt per hour on each square foot of grate, which is, according
to Mr. Parkes, the average consumption throughout England, the minimum area over the bridge, or of
the flue immediately behind the furnace, would be 516 X 13 = 6-709 square inches. In practice, how-
ever, as a large surplus of air is always admitted, and the exactness supposed in this calculation cannot
be secured, it is found advantageous to make the area 2 square inches instead of 516. This gives 26
square inches of area over the bridge to every foot of grate where 13 lbs. of coal are consumed per hour
to every foot of grate. As the temperature and bulk become gradually reduced in proportion to the
distance from the fire, the area of the flue towards the chimney may be narrowed; but this should be
done without awkward bends or sharp angles.
Proportions of heating, or flue surface to size of grate.-In boilers burning 13 lbs. per foot per hour,
18 superficial feet of heating surface to each foot of grate is a good proportion. This proportion omits
the bottom surface of flat flue-, and from 1 to t the surface in circular flues, as being inoperative.
Chimneys.-The area of the chimney should be 4 that of the opening over the bridge, viz. 11 inch
per lb. of coal consumed, or 191 inches for each foot of fire surface burning 13 lbs. per hour. But the
whole diminution of flue should be made gradually, and not by any sudden contraction. A common
rule is, that the minimum area of chimneys 24 to 30 yards high, is 400 square inches for each 20-horse
power.
Chimney at St. Rollox's Chemical Works, Glasgow.
Total height from foundation
447 feet 6 inches.
Depth of foundation
15
=
0
as
Total height above surface 432
"
6
$
Diameter at base
45
"
0
"
"
surface
40
"
0
"
"
top
13
«
B
"
Thickness-bottom 31 bricks. at top 11.
Internal flue 260 feet high, and perfectly vertical.
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FURNACE.
721
Circular chimney at Friar's Grove Chemical Works, near Newcastle.
Extreme height
254 feet 9 inches.
Outside diameter at bottom of foundation
27
"
6
"
Inside diameter at bottom of foundation
14
"
3
"
Thickness
24 feet 8 inches
31 bricks.
Thickness
107 "
3
"
Thickness
53 "
21
"
Thickness
46
u
6
"
2
"
Stone top
6 "
Uniform taper of 11 inch per yard.
Foundation, clay.
The temperature of the furnace and the surrounding flues.-It is a difficulty of no ordinary descrip-
tion to ascertain with sufficient accuracy the temperature of a furnace. In fact every fire and every
furnace is continually changing its temperature, as well as the nature of the volatile products as they
pass off during the process of combustion. When a furnace is charged with a fresh supply of fuel, its
temperature is lowered, and that from two causes first, by the absorption of heat which the cold fuel
takes up when thrown upon the fire; and, secondly, by a rush of cold air through the open door of the
furnace. Attempts have been made to remedy these evils by the aid of machinery and continuous
firing, but taking the whole of the existing schemes into account, and bestowing upon them the most
favorable consideration, it is questionable whether they are at all equal (either as regards efficiency or
economy) to the usual way of working the fires by hand. Provided a class of careful men were trained
to certain fixed and determined regulations, and paid in proportion to the saving effected.
The results of experiments obtained by Mr. Houldsworth's Pyrometer, indicating the mean tempera-
ture of the flues in a steam engine boiler, and the effects produced by the admission of air through
regulated and permanent apparatus behind the bridge, show that in taking the quantity of water evap-
orated by 1 lb. of coal as the measure of economic value, the mean of nearly the whole experiments is
as 100 to 112-65, or about 121 per cent. in favor of a regulated and continuous supply of air. Taking,
however, the mean of some of the experiments, and comparing it with some of the others, it will be
observed that a much higher duty is obtained; and having accomplished a maximum, there appears no
reason for doubting why it should not be continued, and still further advantages secured by a judicious
arrangement of the furnace for the admission of oxygen to the uninflamed gases, which under other cir-
cumstances would make their escape into the atmosphere unconsumed. In furnishing this supply it is
not absolutely necessary to administer it immediately behind the bridge, as the same quantity of air
taken through the grate bars, or in at the furnace doors, would nearly effect the same purpose, not only
as regards the quantity of heat evolved, but also as respects the transparency of the gases and the
consequent disappearance of smoke.
Mr. Houldsworth estimates the advantages gained by the admission of air (when properly regulated)
at 35 per cent., and when passed through a fixed aperture of 43 square inches, at 34 per cent. This is
a near approximation to the mean of five experiments, which gives 831 per cent, which probably ap-
proaches as near the maximum as can be expected under all the changes and vicissitudes which take
place in general practice.
In order to ensure economy and effect in the combustion of fuel, a large and copious supply of air
must be admitted to the furnace, and that in the ratio of 10 volumes of air to 1 of coal gas; when that
quantity is at its maximum or in excess, there is no smoke; when it is different, smoke is invariably
present. Now perfect combustion is the prevention of smoke. It therefore follows, that in order to
render the residue of the products of combustion transparent, or 'smokeless," a supply of air amounting
to ten times that of the gases evolved must be admitted. Should it exceed that quantity the effect will
not be smoke, but an additional expenditure of fuel to supply the loss of heat which this excess of air
would require for absorption, rarefaction, &c. Hence the necessity which exists for power to regulate
the admission, if not the exact, at least an approximate quantity of air. On the other hand, should the
supply be deficient in quantity, (which is often the case,) a dense volume of smoke is then visible, ac-
companied with all the defects and annoyances of imperfect combustion.
It is difficult to determine the exact quantities of gas evolved from every description of fuel, and
probably equally so to supply its equivalent of air; but in order to attain certainty in this respect, let
the openings be made sufficiently large, and by a little attention to the quality of the fuel and quantity
of air required for its combustion, the apertures may be contracted till such time as a mean average
and a close approximation to the maximum effect are obtained.
The concentration of heat is a consideration of much importance in the economy of the steam engine
and the industrial arts; and much depends upon its preservation.
For this purpose we should recommend the flues and furnaces of boilers, and other fires, to be closely
encased with good building material adapted for the retention of heat, and all steam boilers to be well
covered and clothed, 80 as to prevent (as much as possible) the escape of heat in that direction; and
for steam engines, that all the steam pipes, cylinders, &c., should be closely enveloped in a thick coat-
ing of felt, canvas, or wood, and afterwards well painted. These precautions being taken, the effects
will soon become visible in a saving of 15 to 20 per cent. of fuel.
The above extracts are from Reports on English practice, and have their application more particularly
to furnaces using bituminous coal.
On the principle above enunciated, that in the combustion of fuel a certain quantity of air is requisite,
and that either an excess or deficiency is prejudicial to proper and economic combustion, Messrs. Bar-
ron and Brothers, of New York, have constructed their portable blast furnace.
The furnace is 80 arranged that all metals are melted by it at a less expense of time and fuel than
by any other furnace.
91
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FURNACE.
Gold, silver, and copper, can be melted by it in less than ten minutes. No. 1 size will melt from 4
to 12 ounces of gold with less than one quart of coal No. 2 will melt from 50 to 100 ounces with two
quarts of coal; Nos. 3 and 4 from 100 to 500 ounces.
Fig. 1866 represents not only the furnace, but also an operating table, to which is attached blow-
pipes, bellows, &c.; it forms a convenient stand for the furnace, but is not necessarily connected with it.
Fig. 1867 represents a contrivance for supplying it with air by a small pair of bellows resting on a
table. P is the bellows, R a block for the support of the nose of the bellows, to keep it at a convenient
height and distance with respect to the air-pipe O. It will be seen that as the air comes out of the
bellows in a condensed form, by the time it reaches o it begins to expand, and the heat it abstracts by
that action is drawn from the tube O, and not from the fire in the furnace, at the same time the warm
and expanded state in which it reaches the fire, causes it to be equally diffused through the burning
material, and produces throughout an effective intensity of heat.
1866.
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1868.
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1867.
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Fig. 1868 exhibits a section of the furnace. K is an inverted crucible on which another crucible L is
placed, surrounded by fuel. o is the tube through which the air is supplied.
The operating table, Fig. 1866, is not necessarily connected with the furnace-nevertheless its con-
veniences deserve the consideration of the artisan. It is a table covered with a sheet-iron top, having
holes through which are brought three blow-pipes H H H, supplied with air by the bellows C under-
neath, which is furnished with a wind chest whereby a steady stream of air is sustained. Before the
blow-pipes you can place either furnaces F or G, or spirit lamp J, as may be required. The table and
furnace and spirit lamp supply all that is needful to render the melting and soldering of metals safe as
well as easy.
FURNACE, Reverberatory. Figs. 1869 to 1872. These Figs. represent the form and dimensions of
a most important adjunct to Nasmyth's steam hammer, which, with slight modifications, will be found
applicable in many stages of the iron manufacture.
A A, the hearth and building upon which the fur-
nace is erected. It is lined throughout with fire-
bricks, and the hearth is formed at a slight inclination,
so that the flame and heat may more effectually react
1869.
from the arched roof upon the work placed on it.
BB, the roof and sides of the furnace, also formed
of fire-bricks. The roof is arched throughout its en-
tire length, in order that the heat may be reflected
B
and concentrated upon the work placed on the hearth.
CC, the sheet-iron sides of the furnace, by which
the brick-work is secured and retained in its proper
form.
DD, the end plates for binding the side plates to-
gether. Instead of being riveted to the side plates,
they are secured by bolts and nuts, so that the whole
C
structure may be easily taken asunder when it is
@
necessary to rebuild the furnace.
E, the ash-pit.
F F, cross bearers of wrought-iron for supporting
the furnace bars a a a. The ends of the bearers rest
in small cast-iron brackets bb, secured to the sides of
the ash-pit.
G, the passage to the chimney, formed in continuation of the arch of the roof.
H H, the chimney, constructed internally and throughout its entire height, of fire-bricks.
II, corner pieces of ordinary bricks built upon the angles of the interior chimney for the purpose of
giving stability to the whole structure, which is further bound together by bolts ddd passing through
the small cast-iron pieces ccc.
JJ, cast-iron sole plate for supporting the brick-work of the chimney, and which is itself supported by
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1872.
1871.
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724
FURNACE.
K K, four strong cast-iron columns resting on a solid foundation of mason-work.
L, the stoke-hole, through which the fuel is introduced into the furnace. The mouth of this stoke-
hole is so constructed as to admit of its being stopped with a piece of coal when the furnace is in full
operation.
M, a small square aperture in the side of the furnace by which the attendant is enabled to inspect
the state of the furnace without interrupting the progress of the work. It may be stopped with a
single brick.
NN, the main openings into the furnace, through which the shaft or other work to be heated is
passed.
O, the sliding door by which the aperture N is guarded. It consists of a square cast-iron frame,
lined internally with fire-bricks, and fitted to slide vertically between guides of angle iron.
PP, levers working upon the cast-iron brackets QQ, surmounting the furnace. They are loaded at
the outer ends with counter-weights, and attached by short connecting rods to the doors 00, so as to
enable the stoker to raise or lower the latter with the utmost facility.
R, a register or damper surmounting the chimney, for the purpose of regulating the draught of the
furnace. It is brought within the command of the attendant workman by means of a long chain or
wire ee, depending from the lever upon which it is hung.
FURNACES, Hot-air. See WARMING.
FURNACE. Ovens, and machinery used for making bread.
Fig. 1873 represents a front view of a bread machine recently erected in Glasgow, under Messrs.
1873.
Robinson and Lee's patent. One ton and a half of loaf bread, or a ton of biscuit, is produced by this
invention hourly, without the intervention of human labor in any stage, although the machine itself
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FUTTOCK.
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occupies less than a square yard of space. It is well known that the process of setting the sponge, in
the common mode of bread-making, consumes a considerable period of time, and occasions great waste
of the nutritive qualities of the flour. The patentees of this machine state that they prevent both these
losses by the use of carbonated water, which can be very cheaply prepared; but the machine is equally
adopted for those who prefer yeast in the manufacture of bread. By a very simple but ingenious pro-
1874.
1875.
1876.
100
10
42
cess, the liquid and flour are made to fall together in due proportions upon a cone A, which partially
mixes and conveys them into the kneading trough B, whence the dough is forced out at an aperture C,
and cut off by an eccentric knife D in the precise quantities wished. Falling upon a roller E, these
pieces are carried by the same machinery through a moulding tube F, and thence into the oven, Figs.
1874 and 1875; where the steam by which the whole concern has been kept moving is, after passing
through a red-hot coiled pipe in the furnace, Fig. 1876, applied in direct contact with the batch, and
produces a very pure crust. The heat, too, is both indicated and regulated by a self acting pyrometer,
whereby the baker can assure his batch against being either burned or slack baked.
FUSE, for blasting. In this country the safety fuse" is most generally employed. It consists of a
cotton tube filled with powder, wound with tarred thread or twine, and a coat of tar is then applied on
the outside. The whole forms a cord of about 3-16th of an inch in diameter, 80 hard and firm in its
texture as to resist the action of tamping. It is impervious to water, and burns regularly at a rate of
about 21 feet per minute. An improvement on the safety fuse has been patented, namely, the introduc-
tion of a thread in the centre of powder to ensure its continuity, and prevent any chance of a miss-fire.
Powder hose is sometimes used in England, made of strips of linen or cotton cloth sown together, and
filled with powder; these, when full, vary from half inch to an inch in diameter. The hose is inclosed
between two hollowed strips of wood, where it would not be damaged by the tamping, and a piece of
port fire is attached to the match end, to afford time to the blaster to escape before the charge is ex-
ploded.
FUSEE, in clock-work, is a mechanical contrivance for equalizing the power of the main-spring of a
watch; for as the action of a spring varies with its distance from the quiescent position, the power
derived from the force of a spring requires to be modified according to the circumstances, before it can
become a proper substitute for a uniform weight, which is what it is intended to supply. In order,
therefore, to correct this irregular action of the spring, the fusee F, Fig.
1877, on which the chain or catgut acts, is made somewhat conical, 80
1877.
that its radius at every point may correspond with the strength of the
spring, being greater and greater as the action of the spring becomes
more and more weakened by unbending. If the action of the spring di-
minished equally, the fusee would then require a perfect conical figure;
F
but the decrease of the power of the spring does not follow that uniform
law, and, in consequence, the figure of the fusee deviates from the form which it would otherwise take,
and becomes a solid, generated by the revolution of an equilateral hyperbola about its asymptote. See
WATCHES.
FUSIBLE METAL, consisting of 8 parts of bismuth, 5 of lead, and 3 of tin; it melts at the heat
of boiling water, or 212° Fahr. By the addition of a very little mercury it becomes still more fusible,
and is used for certain anatomical injections, and for the filling of carious teeth.
FUTTOCK, or ship timber converting machine. We are glad to have it in our power to lay before
our readers a set of engravings of the machinery of Mr. J. Webster Cochran, of New York, for sawing
Futtocks and other timber used in ship building. We exhibit this machine not merely as described in
his English specifications, but as it has been since improved in many important particulars. We shall
take the specification for the groundwork of our description, and deviate from it only when this may
be rendered necessary by the modifications introduced by the inventor.
Fig 1878 is a front or end elevation of the machine. Fig. 1879 is a side elevation. Fig. 1880 a plan.
Fig. 1881 is a transverse section through the chuck-plate wheel; and Fig. 1882 is a detached view of
part of the steam machinery.
A A A are the stationary framing or sills upon which the sliding carriago of the mill is mounted.
They are firmly fixed, in the usual way, upon the ground, or upon masonry in the building in which the
mill is intended to be placed. Two longitudinal rail plates a a, of the usual description, having V edges
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FUTTOCK.
on their upper sides, are securely fixed upon the horizontal longitudinal sills or beams of the framing,
and upon the V edges of these rail plates the sliding carriage moves in the usual way, for the purpose
of advancing any piece of wood which it may carry up to the saw or saws, in order that it may be cut
into the required shape or shapes.
The sliding carriage in or upon which is to be placed any log or piece of wood intended to be cut,
consists of two longitudinal bars BB, (which form the base of the carriage,) placed parallel to each
other, and braced together into the form of a rectangular frame by the transverse rod b, and the head
block or plate C C.
1881.
1880.
1879.
1882.
1878.
The under sides of the longitudinal bars BB have each a longitudinal groove extending the whole
length of the carriage, and fitted to the V edges of the rail plates aa, 80 that the carriage may slide
easily and securely along the ordinary way.
There are also on the under sides of the longitudinal bars BB two toothed racks, extending along the
whole length of the carriage. These racks are placed parallel with the grooves before mentioned, and
so that a pair of pinions hh' may, when a piece of timber is to be cut, move the carriage along upon
the rail plates a a, by means of trains of wheels connected with the pinions. And when the piece of
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FUTTOCK.
727
timber has been cut, the machinery may be thrown out of geer, and the sliding carriage moved back by
any of several well known means.
The sliding carriage is kept down in its proper position by two friction rollers h²h, one on each side,
which have their edges fitted to the V rails which run along the upper sides of the sliding carriage, as
after mentioned. Each of these rollers is attached to the inside of one of the standards or fender posts
JJ, (within which the sawgate works immediately above" the sliding carriage.)
Upon the head block CC is mounted the poppet head cc, which is made capable of being moved
laterally in a dovetailed groove, for the purposes of adjustment. In this poppet head is an axle, which
carries the chuck plate D, and this chuck plate is made capable of turning freely upon its axis. This
chuck plate has a dovetailed groove extending across the face of it, and having fitted into it the foot of
the jaws or clips dd, the lower of which is made fixed and the other movable.
The movable jaw is kept in its place by two bolts, and by a nut; upon one of these bolts it may be
screwed towards the other jaw, for the purpose of holding one end of a log of wood or piece of timber
firmly in the carriage. And the lower or fixed jaw, or clip, must be mounted in such a way that the inner
surface will at all times coincide with an imaginary line drawn across the face of the chuck plate D, and
through the centre of the axis thereof. These jaws or clips may, by means of the screw shaft g, be
moved across the face of the chuck plate in either direction, as may be required for the purpose of balan-
cing a log or piece of wood, which is to be held between the chuck plates whilst it is being cut.
The head block EE is mounted upon the side bars BB of the sliding carriage. Along the tops of the
side bars BB are V edges, and under and across the ends of the head block E E, are grooves to receive
the last mentioned V edges, 80 that the head block EE, when placed across the sliding carriage, with
its grooves upon the same V edges, may slide easily along. above, or upon the tops of the sliding car-
riage, in the direction which may be required for the purpose of adjustment, according to the length of
the log or piece of timber to be cut.
The head block E E has motion given to it (along the carriage) by means of a pair of pinions, which
are fixed upon a transverse shaft under the head block, and which serve the purpose of keeping the
head block down in its proper position on the carriage. This transverse shaft forms the axis of each of
the last mentioned pinions, and the bearings of the shaft (in which it is made to turn by means of a
hand wheel, handle, or other convenient means) are fastened to the under side of the head block E E.
The last mentioned pinions are placed in such a position that the teeth of these pinions take into the
teeth of the toothed rack, which is placed upon the under sides of the longitudinal bars BB, as before
mentioned; and as the pinions are turned round in the one direction or the other, the head block EE
will be moved towards the one end of the sliding frame or the other.
Upon the head block E E is mounted a puppet head ec, which is made capable of being moved lat-
erally in a dovetailed groove, for the purpose of adjustment, in like manner as the poppet head c c, on
the head block C C. In this poppet head e is an axle, which carries a toothed wheel K, to which is
attached the chuck plate F, and this wheel with the chuck plate is made capable of turning upon its axis.
This chuck plate has a dovetailed groove extending across the face of it, and having fitted into it the
foot of the adjustable jaws or clips ff, which are intended to hold the other end of the log of wood or
piece of timber placed in the sliding carriage to be cut. These jaws or clips are constructed and
mounted in or upon the chuck plate F, in like manner as the jaws or clips dd, which are mounted in or
upon the chuck plate DD.
The fixed and movable jaws of the clips may be made also with quadrant slots. in order that the
movable jaw or clip may be capable of being turned to one side or the other, 80 as the better to grasp
and hold the end of any irregularly formed end of a piece of timber.
In each of these figures there is represented a log or piece of timber m, held in the sliding carriage
by means of the jaws or clips, showing its appearance after it has been submitted to the action of the
saws, and had two of its sides cut so as to make it externally of the required shape.
To place a log or piece of timber in the sliding carriage in a proper position for being cut, one end of
it must be placed between the jaws or clips of the chuck plate D, which is mounted on the fixed head
block cc, and the movable head block E E being then moved to a proper position for enabling the jaws
or clips of the chuck plate F to receive the other end of the log or piece of timber, that end of the log
or piece must then be placed between those joints or clips. The nut of the screw bolt of each pair of
jaws or clips is then to be turned 80 as to bring the movable jaw or clip down upon the log and hold it
securely.
In the place of the roller, which is ordinarily used in sawing mills or machines, for the purposes of
supporting a log or piece of wood, at an intermediate point between the ends, and near to the saws of
the mill, an oscillating cylindrical roller is used, or a roller having its axis capable of being deflected
from a horizontal position.
This roller support is placed at a position as near as conveniently may be to the saws of the mill,
and in front thereof, and must be independent of, and separate from, but within the frame of the sliding
carriage. This roller, and the machinery connected therewith, may be supported by any framing, or
other convenient means, upon the ground, or in connection with the stationary framing of the mill.
G, Fig. 1878, represents a cylindrical iron roller mounted upon an axle in an oscillating segment
piece H. This segment piece is supported by an axle, stud, or trunnion, at each side thereof, which is
mounted in the frame H; these axle studs being placed at right angles with the axle of the roller.
The segment piece H has the semicircular edge thereof toothed, 80 as to take into the threads of the
endless screw L, and the segment piece is held down by a quadrant slot in the segment piece, and
working on a pin or pins in the frame I, so as to allow of the oscillation of the segment piece for the
purpose of varying the deflection of the axis of the roller G, in any manner which may be required.
The quadrant slot is to be made of a sufficient length to allow of the deflection of the roller support
to any extent which may be requisite.
Each side of the frame II is fitted within two upright supporters inn in*, the sides of the frames
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FUTTOCK.
having longitudinal grooves or slots to receive the ends of pins to be driven through the uprights into
the grooves, so as to keep the frame II securely within its two uprights, and yet allow it to be varied
or depressed as may be required.
The frame II is supported by two jack screws 4, 4, which are threaded into the lower part of the
frame II, and the shoulders of these screws work against a stationary rail or bar I*, which is firmly
fixed to the stationary framing, or foundation of the mill.
The lower ends of the jack screws are furnished with bevel wheels 3, 3, which respectively take into
two bevel wheels 2, 2; and the bevel wheels 2, 2, are fixed upon a transverse shaft 1, which may be
turned by a handle or other convenient means. By turning the shaft 1, the bevel wheels will be put
in motion and the jack screws turned, and as these screws are turned the one way or the other, the
frame II may be raised or lowered as may be desired. By these means the frame II, and the roller
G, may be lowered 80 as to remove the roller G out of the way when desirable so to do; and by rais-
ing the frame II and the roller G, the roller may be elevated in such a way as to form an intermediate
support to a log or piece of wood whilst the saws are cutting it.
If the pieces of wood intended to be cut in a mill, should happen to be of such a description that they
will not be held sufficiently steady during the operation of sawing by one intermediate roller support,
such as before described, the same mill may be constructed with an additional oscillating roller support,
(similar to that before described,) and capable of being raised and lowered as before mentioned, and
such additional oscillating roller support may be placed behind the vertical saws, or in any other posi-
tion which may be found desirable, for the farther or better supporting the pieces of wood to be cut in
the mill.
Pieces of wood for shipbuilding, and for various other purposes, frequently require to be cut into irre-
gular shapes, and for the purpose of preparing such pieces of wood of the desired shapes, it is often ne-
cessary that one or more of the surfaces thereof should be cut with a varying bevel or surface, or with
a surface cut in a twisting or winding manner, the bevel or direction of a cut, or cuts, constantly vary-
ing, either regularly or irregularly, in one or more than one direction as the cutting proceeds.
The saws of a vertical saw-mill cannot, as such mills are usually constructed, be moved out of their
perpendicular position, to either the one side or the other for the purpose of varying the bevel or surface
of a log, or piece of timber, which they are cutting.
This object may, however, be attained by gradually turning a log, or piece of timber, which has been
placed in a mill to be cut in the requisite direction, or directions, as the operation of sawing proceeds.
For the purpose of being enabled to turn a log, or piece of wood, during the cutting thereof, this in-
proved sawing machine is constructed with revolving chuck plates and oscillating segment pieces, with
roller support, or supports, as before described.
These chucks and the intermediate roller support, or supports, may be turned in the manner required
by the hand, or by any convenient machinery effecting that object, such as that now about to be described.
The teeth of the wheel K, behind the chuck plate F, take into an endless screw L, as shown in Fig.
1881, which is fixed upon a transverse shaft K¹, and in like manner the teeth of the oscillating segment
piece H take into the endless screw L'. The chuck plate D may, if it should be thought desirable, be
furnished with a rim of teeth taking into an endless screw in like manner; but a machine will work
sufficiently well for all ordinary purposes without this addition to the machine as represented in the
figures.
When a log or piece of wood has been placed with its ends in the jaws or clips of the turning chuck
plates, the roller support G must be raised until the upper surface thereof comes in contact with the
log; and the mill or machinery must be put into geer in such a way that the direction and degree of
the inclination (if any) of the axis of the roller support G to the horizon must at all times be the same
as that (if any) of the face of the fixed jaw or clip of the chuck plate F.
The chuck plate F, and the segment piece H, must at all times be turned together in the same
direction, and in the same degree, or with the same speed; and the chuck plate D being left free to turn
upon its axis, will be turned as the log or piece of wood may be turned.
Upon the end of the driving shaft K¹, of the endless screw taking into the teeth of the chuck wheel
K, is fixed a bevel wheel K³, taking into another bevel wheel K' upon the driving shaft y, which last men-
tioned wheel is prevented from turning upon the shaft by means of a feather or key in the boss of the
wheel, which takes into a groove along one side of the shaft y. For the purpose of preventing the
shaft y from springing, and also for keeping the bevel wheel K' in geer with the other bevel wheel Kᵃ,
a collar K° is fitted upon the boss of the bevel wheel K⁴, (within which collar the boss of the wheel
turns freely ;) and the collar is attached by its arm to the under side of the head block E.
The boss of the wheel K' is kept in its place within the collar K' by a narrow collar fastened upon
the outer end of the boss by a set screw.
And as the head block E on the sliding carriage, with the same head block, is moved along in either
direction, the bevel wheel K4 which the shaft y turns will be moved along at the same time, and kept
in geer with the other bevel wheel K', with which it is intended to work.
The driving shaft K" has its bearings in the movable frame II, with which it must rise and fall.
One end of this driving shaft passes through its bearings in one side of the frame II, and through the
next adjoining upright inn, in which a slot is cut, 80 that the shaft K' may pass up and down within
the slot, as the frame I I rises and falls. The shaft K' has its outer end fitted into a hole or bush in
the collar upon the boes of the wheel, 80 that the collar must be raised or lowered in like manner as the
end of the axle which works within the same bush or hole.
Upon or near to the end of the shaft K³, which is next to the collar, is fixed a bevel wheel, which
takes into another similar bevel wheel. The bevel wheel, with its long boss below it, is placed upon an
upright driving shaft, which has a groove or key-way cut along one side of it, to receive a feather
placed in the inside of the boss of the bevel wheel, which is made to move freely up and down within
the groove.
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The bevel wheel and its boss move freely up and down upon the shaft, and the boes of the bevel
wheel, which turns freely within the collar, is kept securely within that collar by means of a narrow
collar fastened upon the end of the boss by a set screw, in the usual manner. The bevel wheels are
thus at all times kept in geer with each other.
The shaft has its bearings at the foot in a socket or step, and at the top in a bracket, as shown.
Upon the top of the shaft is fixed a bevel wheel, which takes into another bevel wheel fixed upon
the shaft y.
The boss of the bevel wheel nb is made to move in a bearing or bush at one end of a bracket or arm,
within which the boss turns freely, and the bracket or arm is fixed to the frame I*, and by these
means the shaft y is kept steady, and in its proper position whilst in motion.
When the driving shaft y is left at rest, the movable chuck plate F, and the segment piece H, with
the roller G, will also be left in a state of rest; that is, they will not be turned either to one side or
the other of the machine. And when it is unnecessary that a log or piece of timber should be turned in
either direction during the process of cutting, for the purpose of producing a piece of wood of the in-
tended shape, then the chuck plates and roller support are to be left in a state of rest; and if the chuck
plates and roller support are turned by machinery, as shown in the figures, then also the driving shaft y,
and all the machinery connected therewith and before described, are to be left in a state of rest.
But when it is necessary that a log or piece of timber should be turned during the process of cutting,
then that may be done by hand, as before mentioned; or if the machine be such as before described,
then motion is to be given to the shaft y, and such motion regulated and (when necessary) accelerated
or retarded by the machinery next to be described. And whenever motion is given by means of the
driving shaft y to the transverse driving shaft K¹, and the movable chuck plate F, a similar motion
will, by means of the train of wheels before described, be also communicated to the transverse driving
shaft K², and the segment piece H, carrying the roller support G.
To show more clearly the mode in which the saws are mounted and worked, we have given in Fig.
18824 a front elevation of the machine, with all the parts removed that have no relation to this branch of
the invention, and also in Figs. 1883, 1884, 1885, 1886, 1887, and 1888, 1889, some of the more im-
portant of the minor details. Although any required number can be used at the same time, the saw-
gate is represented as fitted with two saw blades with their respective shackles and sliding frames;
but as both saws are actuated by precisely similar means, we shall, for the sake of greater distinctness,
confine ourselves to describing the parts belonging to one saw blade only.
The sawgate M M consists of two top and bottom rails C O, which are connected together by the
upright rods N N, to the lower end of which are jointed the rods by which motion is communicated to
the gate from the cranks of the main driving shaft. The saw blade i is attached at the top and bottom
to two cylindrical axes G G, which are separately represented along with the parts peculiar thereto in
Figs. 1883, 1884, 1885, 1886; Figs. 1883, 1884, 1885, being side elevations, and Fig. 1884 a cross section on
the line E F of Fig. 1886. The axes G G are hollowed out in the centre from a to b, as represented in
the cross section, Fig. 1884, and fit by means of the parts 80 hollowed out upon the projecting pieces
H H, which form the extreme ends of the top plates of the shackles IL The form of these projections
H H is shown separately in Fig. 1887, which is a plan of the top plate of the shackles. When the axes
G G are fitted upon H H, and the saw connected to them by the pins cc, the saw blade is brought to
the proper degree of tension by means of the top screws X'X'. The points of these screws, which are
conical and made of hardened steel, take into hollows formed in the pieces H H, so that the saw blade
has thus, in so far as respects the screws by which it is stretched, perfect liberty to turn round in any
direction, the friction of the bearing parts presenting a very trifling obstacle to its rotation. The saw
is, however, limited at the same time in respect of angular motion by the sides of the recesses formed
in the axes G G, and the neck which connects the bearing points H H of the shackles II; the range
allowed to the saw by the parts just described being still sufficiently extensive for all practical pur-
poses. (It may be turned till it stands at an angle of 45 degrees, or even a greater angle, with the
central line of the sliding carriage upon which the wood to be cut is placed.) It is to be observed, that
when the saw is stretched, the points of resistance to its tension are not the rails of the sawgate; for
the strain falls entirely upon the shackles or buckles II, which, together with the rods L and M, form a
frame complete in itself, which fits accurately into and slides upon the sawgate. By this improved
method of mounting the saw, great facilities are obtained for connecting and disconnecting it from the
frames, while the friction of the bearing points being reduced to a very small amount, the workman is
enabled to direct the course of the saw in any intended line with great precision and ease.
On the rod or strut L there is closely fitted a hollow shaft or tube 0°, two ends of which bear against
the top and bottom shackles II. So that by this means it is prevented from moving in a longitudinal
direction upon the rod L, but is still left free to be turned round upon it, as on an axis. To the upper
and lower ends of the shaft or tube, there are securely fixed cross arms 0ª O', corresponding with similar
cross arms P' P', which are keyed upon the axes G G of the saw. These two sets of cross arms are
again connected with each other by rods qq, (a plan of which is given in Fig. 1888,) 80 that, if the
hollow shaft O° be made to turn by any means either to the right or left, an equivalent movement of
the saw upon its axes G G takes place at the same time. PP are two round rods, which are secured
to the upright standards of the framework of the machine, and occupy positions parallel to each other,
and also parallel with the sawgate. T is a bridge, or sliding bearing, which is free to slide to and fro
upon the rods PP, that is, from one side of the sawgate to the other, being attached to the rods by the
bosses dddd U and p' are two bosses inserted into the upper plate of the bridge T, in such a way
that they are at liberty to revolve in the holes into which they are inserted while they are prevented
from getting out of their places by collars ff formed on, or affixed to, their upper and lower ends. One of
these bosses, U, embraces the upright hollow shaft 0°, and allows of its moving freely up and down
within it. On the side of the hollow shaft 0 there is a feather 6 which takes into a corresponding groove
formed in the boss U, 80 that if the boss is made to revolve, the hollow shaft must go round along with
92
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FUTTOCK.
it. W is a worm-wheel which is attached to, or formed in one piece with the brass U, and geers into
an endless screw X, upon the end of which there is a hand-wheel X', 80 that the attendant may be
enabled, through the intervention of the endless screw X, the worm-wheel W, the hollow shaft 0, the
cross-arms 0ª P', and the rods qq, to cause the teeth of the saw to be directed at pleasure, more or less
towards the right or left, according to the form desired to be given to the piece of wood.
1882f.
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When the saw has been inclined towards either side of the sawgate (by means of the apparatus
before described) during the operation of cutting a log or block of wood, the regular feeding in of the
wood takes place by the advance of the travelling bed under the sawgate. The saw would, therefore,
very soon be broken unless the shackles were made by a free lateral motion, or some other means, to
advance towards that side of the sawgate to which the teeth of the saw are directed. To effect this
object, the arrangement next to be described is adopted: V' is a hand-wheel fixed upon, or made in one
piece, with the brass Pᵃ, which is connected with a hollow shaft 0* upon the rod M; being in this
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respect exactly similar to the hollow shaft, 0° and brass U, before described. The hollow shaft 0* has
pinions Y Y affixed to each end, which geer into racks Y' Y', which last are fixed to the upper and
lower rails of the sawgate. In general the draft of the saw itself is sufficient to cause the shackles to
move along the sawgate; but whenever any obstruction to the lateral movement is experienced, all
that the attendant has to do is to turn the hand-wheel Vs in the required direction, which causes the
pinions Y Y, by geering into the fixed racks, to draw the shackles and saw along with them.
The arrangements which have just been described for regulating the lateral and simultaneous move-
ment of the shackles, both at top and bottom of the sawgate, serve the further purpose of keeping the
saw at all times vertical in the sawgate, it being impossible, on account of the racks and pinions, for one
of the shackles to be moved without a corresponding movement being produced in the other.
Not only may the machine be worked with either one or more saws at a time, but one saw may be
used to cut in a curvilineal direction, while the other cuts in a straight line.
Thus if both or either of the sides of a log should be intended to be cut in a curved or irregular
line, that object may be attained by turning, from time to time, the saw in the required direction; and
when simultaneously making two cut, in a log by my said machine, it is not at all necessary that the
cuts should be made parallel with each other, for the lateral movements of the saw within the sawgate
being perfectly independent of each other, each saw may be turned in the required direction for the
purpose of making the intended cut in the line described, however much the two lines to be cut by the
two saws may vary from each other.
" Neither is it necessary that two saws should be actually used for the purpose of cutting timber in
one of my said machines, although two saws may be mounted in the sawgate; for the peculiar con-
struction of my said sawing machine may be made available for the purpose of making single as well
as double cuts. And if it should happen that the shape into which a piece of timber is intended to be
cut requires the adoption of such a mode of proceeding, I can enter one of the saws and commence
cutting a piece of timber with it, and after the cutting with one saw has proceeded the requisite dis-
tance, I can then enter the other saw also, so that both saws may then proceed with the cutting of the
log; or the cutting with either or both of the saws alternately or simultaneously may be varied from
time to time, as may be required for the purpose of cutting the pieces of timber into the desired
shape."
This invention has recently been introduced into England from this country, and has been in active
operation for two years in the government dock-yard at Woolwich, where the estimation in which it is
held is fully testified by certificates of the highest officers of the admiralty, and other persons of dis-
tinction, in Europe, competent to judge of its merits. It has also been adopted by the government of
Sweden; has met the approval of the officers of the Russian government and of several other conti-
nental naval boards. We are confident that the machines erected at Woolwich in 1847 were the first
and only ones that ever had converted compass timber for a ship's frame for actual use. Mr. Cochran
is now under contract for the construction, in England, of machines for the dock-yards of that country.
Machines are now in the course of erection in this city, and are considered by the most competent
judges to be one of the greatest improvements of the present day. Cochran's Patent Machine for
Sawing Ship Timber" is capable of cutting both straight and crooked work at the same time. One
futtock can be sided at the same time the curvilinear and bevelled sides of another are being sawed, or
a straight timber can be cut at the same time that a crooked one is sawed into planking, with the grain
of the wood.
FUTTOCK PLATES. Flat iron bars or plates, receiving at one end the lower dead-eye of the top-
mast rigging, and at the other the futtock shroud.
FUTTOCKS. In nautical language, the timbers between the floor timbers and the top timbers.
GALVANISM. This term is generally used as synonymous with that of voltaic electricity, or the
phenomena resulting from the evolution of electricity by the contact of different metals, or by chemical
action, as manifested by the galvanic or voltaic battery. For descriptions of some of the more useful of
these batteries and their practical application, see ELECTRICITY, ELECTRO-METALLURGY, TELEGRAPH.
GALVANIZED IRON. Iron covered with a coating of zinc and tin. This process is as follows:
Clean the surface of the iron perfectly by the action of dilute acid and by rubbing; then plunge it first
into a bath of zinc, stirring it about till it is alloyed superficially with this metal; then immerse it
in a bath of tin, such as is used for making tin plate. The tin forms the exterior coat. Iron thus pre-
pared is found to withstand the action of rust much longer than tin plate, and is now used extensively
for gutters and leaders, and in other exposed situations.
GALVANOMETER An instrument for ascertaining the presence of a current of electricity, espe-
cially galvanic or voltaic electricity, by the deviation which it occasions in the magnetic needle. The
simplest form of galvanometer is a magnetic needle poised upon a point, and surrounded by one or more
coils of copper wire covered with silk, the ends being either left free or terminating in two small copper
cups containing mercury, for the convenience of communication with the source of electricity. When
this needle is placed parallel to the coil, and in the magnetic meridian, it immediately deviates when
the electric current passes through the coil; and the deviation is either to the east or the west, according
to the direction of the current. See ELECTRO-MAGNETISM.
GAS, and the machinery employed in the manufacture of. All substances, whether animal, vegetable,
or mineral, consisting of carbon, hydrogen, and oxygen, when exposed to a red heat, produce various
inflammable elastic fluids, capable of furnishing artificial light. We perceive the evolution of this
elastic fluid during the combustion of coal in a common fire. Bituminous coal, when heated to a certain
degree, swells and kindles, and frequently emits remarkably bright streams of flame, and after a certain
period these appearances cease, and the coal glows with a red light.
The flame produced from coal, oil, wax, tallow, or other bodies which are composed of carbon and
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GAS.
hydrogen, proceeds from the production of carburetted hydrogen gas, evolved from the combustible
body when in an ignited state.
If coal, instead of being burnt in the way now stated, is submitted to a temperature of ignition in
close vessels, all its immediate constituent parts may be collected. The bituminous part is distilled
over, in the form of coal-tar, &c., and a large quantity of an aqueous fluid is disengaged at the same
time, mixed with a portion of essential oil and various ammoniacal salts. A large quantity of carbu-
retted hydrogen, carbonic oxide, carbonic acid, and sulphuretted hydrogen, also make their appearance,
together with small quantities of cyanogen, nitrogen, and free hydrogen, and the fixed base of the coal
alone remains behind in the distillatory apparatus, in the form of a carbonaceous substance called coke.
An analysis of the coal is thus effected by the process of destructive distillation: the products which
the coal furnishes may be defined as follows:-
Oxygen, which was discovered by Priestley in 1774.
This gas has resisted all attempts to convert it into a liquid; it is colorless and inodorous, and
heavier than atmospheric air, 100 cubic inches weighing 34193 grains, while 100 cubic inches of the
latter only weigh 31.0117. As atmospheric air is considered as unity when comparing the density of
gases, the specific gravity of oxygen is 1.1026. It eminently supports combustion, all combustible
bodies when introduced into it burning much more vividly than in common air; indeed it is to the
presence of this gas that the property of supporting combustion, which common air possesses, is owing.
Hydrogen was discovered in the year 1766 by Cavendish. It is gaseous, and the lightest body
known, its specific gravity being only 0-06896. This gas is colorless, and, when perfectly pure,
inodorous. It is not perceptibly dissolved by water: it has a powerful affinity for oxygen, and is there-
fore eminently combustible. Intense heat is developed by the combustion of hydrogen in oxygen gas,
but little light: the compound thus produced is water.
Carbon is well known under the form of coke, charcoal, lampblack, &c. It is one of the principal
constituents of all varieties of coal, and is the basis of the illuminating gases.
It is a colorless and inodorous gas, rather lighter than common air, having a specific gravity of 0-9727;
is sparingly absorbed by water, and does not precipitate lime-water. It is inflammable, burning with
a beautiful blue flame; the product of its combustion is carbonic acid. Carbon unites with hydrogen
in many proportions, and many of these compounds are produced during the distillation of coal, but the
only two of importance are carburetted hydrogen and olefiant gas.
Carburetted Hydrogen is abundantly formed in nature in stagnant pools, ditchés, &c, wherever vege-
tables are undergoing the process of putrefaction: it also forms the greater part of the gas obtained
from coal. Carburetted hydrogen consists of 100 volumes of vapor of carbon and 200 of hydrogen.
It is colorless, and almost inodorous; is not dissolved to any extent by water and is much lighter than
atmospheric air, its density being 0.5594. It is very inflammable, burning with a strong yellow flame
the products of its combustion are carbonic acid and water. The carburetted hydrogen, or coal-gas,
when freed from the obnoxious foreign gases, may be propelled in streams out of small apertures,
which, when lighted, form jets of flame, which are called gas-lights.
Olefiant Gas is thus named from having the property of uniting and forming an oily substance with
chlorine. It is a product of the distillation of oil, resin, and also of coal, when the process is well con-
ducted. It is colorless, tasteless, and without smell when pure. Water dissolves about one-eighth of
its bulk of this gas. It is formed of two volumes of hydrogen, and two of the vapor of carbon, con-
densed into one volume. It burns with an intense white light, and requires a large portion of
oxygen for its combustion; one volume of the gas requiring not less than three volumes of pure oxygen,
or fifteen volumes of atmospheric air, for decomposition. The products of the combustion are water
and carbonic acid.
Sulphur exists in coal as an impurity, under the form of the sulphuret of iron. During the distilla-
tion it is decomposed, the sulphur combining with a portion of hydrogen, and escaping under the form
of sulphuretted hydrogen gas, part of which unites with the ammonia, and is condensed in the aqueous
fluid which floats on the surface of the tar; while another portion escapes uncombined, and would mix
with and deteriorate the gas, were it not intercepted by the lime purifiers.
Sulphuretted Hydrogen is a colorless gas, with an offensive taste and odor, resembling that of putre-
fied eggs. It dissolves in its own bulk of water, to which it communicates its taste, odor, and character-
istic properties. It is combustible, burning with a blue flame, and emitting a suffocating smell similar
to that of a burning match. During the combustion its hydrogen unites with oxygen to form water,
while its sulphur unites with another portion of oxygen to form sulphurous acid. It is to the presence
of the vapor of this substance that the disagreeable property of tarnishing metals which characterizes
the combustion of impure gas is owing. Its specific gravity is generally estimated at 1.178.
Nitrogen is one of the constituents of coal. It has the property of extinguishing burning bodies, and
is not absorbed by water; its specific gravity is 0.9760, being lighter than common air, of which it
forms a constituent part.
Ammonia is formed during the distillation of coal, and of all organic substances containing nitrogen.
In such distillation the nitrogen unites with hydrogen in the proportion of one to three, and ammonia is
the result. It is a colorless gas, very pungent, acting strongly on the eyes and nose when respired. It
dissolves in a very small portion of water, one volume taking up about 750 of the gas, forming a liquid
possessed of similar properties, and sold in the shops under the name of Spirits of Hartshorn.
The presence of Cyanogen is frequently detected in coal-gas before purification; it contains its own
bulk of nitrogen, and twice its volume of the vapor of carbon.
Chlorine is one of the elementary substances, supporters of combustion. It is possessed of striking
properties, but that which alone is of interest at present is its action on olefiant gas. On mixing
chlorine with a gas in which olefiant is contained, a diminution of volume is observed, and drops of oil
are seen to fall on the surface of the water over which the operation is conducted. This fact enables
us to estimate correctly the bulk of olefiant in any given portion of mixed gases.
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With a view to the generation of gas on a large scale, the coal is put into vessels called retorts, and
furnished with pipes connected with reservoirs, to receive the distillatory products. The retorts are
fixed into a furnace, and heated to redness: the heat develops the gaseous and liquid products of the
coal the latter are deposited in receivers or tanks, and the former conducted through lime-water, or
thin strata of the hydrate of lime, and purified. The sulphuretted hydrogen and carbonic acid, which
are mixed with these, become absorbed by the lime and moisture, and the pure carburetted hydrogen is
stored up in a vessel called a gasometer, and is then ready for use. From the reservoir in which the
gas has been collected proceed pipes, which branch out into small ramifications, until they terminate at
the place where the lights are wanted and the extremities of the branch pipes are furnished with stop-
cocks, to regulate the flow of the gas into the burners or lamps.
The production of gas-lights is therefore analogous to that of flame produced from tallow, wax, or oil.
All these substances possess, in common with coal, the elements of certain matters, which are capable
of being converted into inflammable elastic fluids by the application of heat.
The capillary tubes, formed by the wick of a candle or lamp, serve the office of the retorts, placed in
the heated furnace in the gas-light process, and in which the inflammable gaseous fluid is developed.
The wax, tallow, or oil, is drawn up into these ignited tubes, and is decomposed into carburetted hydro-
gen gas, and from the combustion of this substance the illumination proceeds. In the lamp, as well as
in the candle, the oil or tallow must therefore be decomposed before they can produce a light; but for
this purpose the decomposition of a minute quantity of the materials successively is sufficient to give a
good light: thus originates the flame of a candle or lamp.
Nothing more therefore is required in the gas-light process which coal affords, when submitted to a
temperature of ignition in a close vessel, than to collect these products in separate reservoirs, and to
convey one of the products, the inflammable gas, by means of pipes and branching tubes, to any
required distance, in order to exhibit it there at the orifice of the conducting tube, so that it may be
used as a candle or lamp.
The whole difference between the greater process of the gas-light operation and the miniature
operation of a candle or lamp, consists in having the distillatory apparatus at the gas-light manufactory
at a distance, instead of being in the wick of the candle or lamp-in having the crude inflammable
matter decomposed, previous to the elastic fluid being wanted, and stored up for use, instead of being
prepared and consumed as fast as it proceeds from the decomposed oil, wax, or tallow; and lastly, in
transmitting the gas to any required distance, and igniting it at the burner or lamp of the conducting
tube, instead of burning it at the apex of the wick.
Retorts.-The proper mode of constructing retorts in which coal
1890.
is distilled, and the art of applying them, form objects of primary
importance in every gas-light establishment.
The forms of the retorts used at the present time are various. The
annexed Figs. 1890, represent sections of a retort, of cast-iron, com-
monly known by the name of a D. The charge is 3 bushels, or 21 cwt.,
which may be drawn at the end of six hours. The dimensions can-
not be increased with economy beyond those marked on the draw-
ings. Retorts of smaller dimensions are more usually adopted.
Mode of setting a bench of five D retorts.-These Figs. represent a front elevation, two sections and
plan of a bench" of five common retorts, such as are in general use.
Fig. 1892 is a front elevation. Fig. 1893, a transverse section, through a b in Fig. 1894. Fig. 1894,
a longitudinal section, through c d in Fig. 1893.
Fig. 1895 is a plan showing the furnace and side openings below the fire-tiles, on which the lower
retorts rest, and the bedding of the lower retorts. Fig. 1896 is a plan over the three lower retorts, the
two upper retorts being removed. Fig. 1897 is a plan over the oven-arch, showing the flues, &c.
The same letters refer to corresponding parts in the several views.
A. Retorts of the kind called D's. Some engineers prefer those of a cylindrical form, but D's allow
of the coal being laid in thinner strata, consequently it is more evenly acted upon by the heat, an
advantage under every circumstance. Set in the manner shown in the Figs. the bottoms of those
retorts placed immediately over the furnace are well protected. The dimensions are-length 7 feet,
diameter 1 foot 2 inches, thickness of metal 11 inch. Their weight is about 15 cwt. of cast-iron.
The most economical charge is two bushela, or 11 cwt. of coal to each retort, drawn at the end of six
hours. This charge will fill the retort to the depth of about five inches; if the coal be moderately
small, the layer will be rather less in thickness. At a heat of 27° of Wedgewood's pyrometer, or that
of melting copper, each charge ought to produce about 650 cubic feet of gas, of the specific gravity
400, (the specific gravity varies between 390 and 420, according to the heat at which the retorts are
worked, and the quality of the coal carbonized,) from Newcastle coal, making the products of the entire
bench equal to 3250 cubic feet in six hours.
To introduce the coal into the retorts, a "scoop" ought to be employed,
1891.
in preference to the primitive mode, with a shovel. The scoop is a semi-
cylinder made of thin plate-iron, six feet six inches long, and twelve inches
in diameter, with a cross-handle at one end, represented in Fig. 1891.
The charge for the retort is placed in this; one man takes the cross-
handle, and two others at the opposite end lift it with its contents up to
the retort; it is then pushed forward, quite to the bottom, turned round,
and withdrawn immediately, and the coal left in the retort raked into an
even stratum.
The lid, previously luted, is now quickly jointed on to the retort-mouth. It must be obvious that
the loss of gas by this simple method is very trifling, the whole operation not occupying more than forty
seconds; whereas, when the shovel is used, the coal is thrown in 80 much by degrees, that more gas is
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GAS.
lost, owing to the greater length of the operation, and the heat producing some effect on each separate
shovelfull: in either case the loss is inconsiderable.
Previous to drawing the charge, loosen the lids of the retorts, and apply a light to the issuing gas,
beginning at the upper retorts. This precaution is necessary to prevent explosion.
S is the mouth-piece, ten inches long, with a socket cast on the top to receive the stand-pipe. There
ought to be a neck to this socket, as shown in Figs. 1892 to 1894; because the joint, when close upon
the top, from its greater thickness, retains much heat, and decomposes the tar which will accumulate at
this place and eventually choke the pipe with hard carbon. The length of the neck may be from four
to five inches.
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1892.
1893.
The mouth-piece is three-quarters of an inch in thickness, secured to the retort by bolts, and a
cement joint made between their flanches. Iron cement is the most valuable for this purpose, and is
used in all places where heat is present. It may be compounded as follows: To one ounce of sal-
ammoniac, add one ounce of flowers of sulphur, and thirty-two ounces of clean cast-iron borings; mix
all well together, and keep the composition dry. When the cement is wanted for use, wet the mixture
with water, and when brought to a convenient consistence, let it stand for a few hours; then apply it
to the joints, and screw them together. The flanches ought to be kept about three-eighths of an inch
apart, by wrought-iron wedges, and the cement well filled in between them with a square blunt-pointed
chisel, called a caulking-chisel; the cement is stopped from being driven through by a hoop of thin iron
placed inside the pipe or retort to be thus operated upon, which is afterwards removed. A consider-
able degree of action and reaction takes place among the ingredients, and between them and the iron
surfaces, which causes the whole to unite as one mass; the surfaces of the flanches become joined by
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1894.
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1895.
1896.
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GAS.
a species of pyrites, all the parts of which adhere strongly together. Mr. Watt found that the cement
is improved by adding some fine sand from the grindstone trough.
A very economical joint for the retort mouth-piece is made of five parts of fine clay, and one part of
the mixture just described.
The face of the retort mouth-piece is bevelled inwards, and is chipped and filed, if necessary, to re-
move any lump that would prevent the lid from fitting close; a clean and true casting, however,
seldom requires this to be done.
1897.
R
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The lid is jointed on to the face of the mouth-piece, with "luting" made of the spent lime from the
dry purifiers, mixed with a little fire-clay, and tightened into its place by a strong, square-threaded
screw, and cross-bar of wrought-iron, the ends of the cross-bar being passed through projecting ears,
against which it bears when the screw is turned.
B is the "stand-pipe," through which the gas, as it is generated, passes from the retort; it is three or
four inches in diameter at the top, increasing to five inches at the bottom, to prevent the tar which
adheres to the lower parts from obstructing the flow of the gas. The lowest joint is made with a socket,
instead of a flanch, to allow for some expansion without injury.
B' is the "bridge-piece," connecting the stand and dip-pipes.
C is the "dip-pipe," passing through the upper metal of the hydraulic main, upon which it is jointed,
and having its lower extremity, which is three inches in diameter, immersed four or five inches into the
tar contained therein. The holes in the hydraulic main, through which the dip-pipes pass, are generally
drilled and chipped out while the apparatus is in process of erection; because they are at unequal
distances from one another. The height of the dip-pipes from the surface of the tar, measured from
the lower bend of the bridge-piece, ought to be sufficient to contain the perpendicular head of tar forced
up into them by the pressure of the gas from the working retorts. This would probably in no case
exceed three feet.
DD are the bonnets, to be removed when the pipes require clearing, jointed by putty and paste-
board.
E is the "hydraulic main," running the entire length of the retort-house, over the benches, in a per-
fectly horizontal direction, and sufficiently high up to allow of head-room; and to be removed from the
flame issuing from the retorts while charging. They are sometimes turned the reverse way to that
shown in the Figs, and made to rest upon the brickwork of the benches; but this is inconvenient when
the brickwork has to be taken down or repaired.
This main is three-quarters of an inch in thickness, and cast in convenient lengths, contrived to reach
over two benches; in this case they would be equal to 13 feet 6 inches. The joints are made with iron
cement. Its use is to cut off the communication between the retorts, when one or more benches are
charging or open. Being half full of tar, the gas evolved from the retorts in action remains in the upper
part, and the ends of the dip-pipes immersed under the surface are effectually sealed.
The diameter of the hydraulic main must be sufficient to form a reservoir capable of supplying the
quantity of tar contained in the open dip-pipes without suffering it to fall below their immersed ends,
and thus open a communication between the open and working retorts.
In the general arrangement of the hydraulic main two things must be observed. First the diameter
must be sufficient to supply at least 20 inches perpendicular head of tar to each dip-pipe, without
causing the general level to fall below their immersed ends; and secondly, the lower part of the cir
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cumference of the pipe, which conveys the gas to the condensers, must be 80 placed that the tar may
always be kept from rising too high, and either choking the free exit of the gas or increasing the working
pressure of the retorts unnecessarily. The diameter of the main in the engraving is 18 inches-amply
sufficient for fifteen benches of retorts.
F is a light, hollow, cast-iron pillar, supporting the hydraulic main in the centre of each length; it is
based upon the cast-iron girder which supports the firing-floor.
G is the pipe through which the gas makes its exit from the hydraulic main to the condensers,
furnished with a slide-valve to disconnect the mains at each side of the house, when at any time it may
be found requisite to repair or clear them.
H is a small pipe for conveying the surplus tar formed in the hydraulic main to the tar-well situated
beneath the firing-floor; its lowest extremity is sealed, by being immersed in the tar contained in the
well, or in a small vessel by the side and connected with it; the latter is the most convenient. This
surplus pipe is not absolutely necessary, because the siphon at the bottom bend of the first stand-pipe
would perform its duty, but it is advisable to draw off the tar as soon as possible.
In the construction of retort-houses the firing-floor is raised upon flat 9-inch brick arches over the
coke vault, high enough to give head-room, a space about 24 inches wide being left in front of the
benches for the coke to fall through when drawn from the retorts: it should be of such a material as
will not be injured by frequent blows; some prefer cast-iron. The flat arches supporting the floor
spring from cast-iron girders fixed at one end in the brickwork of the benches, at the other in the wall
of the retort-house. The distance between the centre and centre of these girders is six feet nine inches.
L is the furnace for heating the retorts; its breadth is 14 inches, the length of the fire-bars 24 inches.
The bars are placed loosely upon the bearers, and must occasionally be clinkered," or lifted from their
seat in the front and cleared from the slag which adheres to them.
M M are side openings, three inches square, left in the brickwork, through which the heat of the
furnace passes.
N N are 4}-inch walls, built of fire-bricks, one between each of the openings M; they serve to
support the fire-tiles T, on which the outside lower retorts rest. The direction of the flues is shown by
arrows.
P P are fire-bricks, placed on end, and a fire-lump, upon which the two upper retorts rest. The heat
acting on these being somewhat moderated, no guards of fire-tiles are necessary.
o o are openings, 3 inches by 41, in the crown of the main arch communicating with the branch flue.
Q is the branch flue, one being built over the centre of each bench of retorts.
R is the main flue, running the entire length of the benches, and connected with the chimney into
which all the branches lead. Between this main flue and each branch is a damper Z, to regulate the
draught through the furnaces.
S'S' are cast-iron plugs, covering sight-holes, through which the heat of the retorts is seen and judged of.
V is the furnace-door, protected by a fire-lump inside.
W is a cast-iron plate, 11 inch thick, on which the fire-door is hinged, serving also to protect the face
of the brickwork which it covers. In the centre, and about six inches above the fire-door, a square
opening is cast for the admission of an iron spout, when it is required to burn tar.
X is a pan at the bottom of the ash-pit, for evaporating ammoniacal liquor, and the offensive unsale-
able liquid products which cannot be disposed of otherwise.
Y Y are openings left in the walls N, by which the carbon deposited from the furnace is cleared away.
It must be obvious that the durability of the distillatory apparatus greatly depends on the manner
in which the heat is applied to effect the decomposition of the coal contained within the retort. If the
heat be very intense, the whole vessels are rapidly destroyed; if it be too languid, the distillation is
protracted, the gas is of inferior quality, much fuel, time, and labor are wasted to no purpose, and the
retorts are speedily deteriorated, as the heat acts upon one part more than upon another. The experi-
ments by which the present plan of heating retorts was arrived at, were many and expensive. Origi-
nally they were built in brickwork singly, and heated by flues passing beneath and over them, without
any guard, except in some instances that of an iron saddle. They were afterwards placed in pairs,
then in a great number; but nevertheless, until the guard of fire-tile was used, the wear and tear was
enormous.
The great obstacle to working more than two retorts to one furnace evidently arose from the diffi-
culty of conducting the heat by means of flues around the series of retorts in such a manner that it
should act with equal force on all. Different workmen constructed these flues in different ways: in
short, the forms varied in every possible manner, and still with the same result. The fuel required for
heating the retorts, when set without guards, was less by nearly ten per cent. than that required for
the same purpose on the oven plan; but the greater duration of the retorts much more than compen-
sated for the additional fuel.
The oven represented in Figs. 1893 and 1894 is one of the latest arrangements. The heat from the furnace
passes through the square openings M at each side, and is thus equally divided along the whole length
of the retorts; from between the walls N it rises between the fire-tiles at the outer sides of the lower
retorts. The flame is not suffered to impinge upon any part, but is equally distributed throughout the
oven, and consequently the retorts work and burn out" evenly. The lower retorts, which would
otherwise be exposed to a more direct heat, are carefully guarded by fire-tiles, which at the same time
prevent the bottoms from bulging. The openings 0 at the top of the main arch act more in the manner
of safety-valves than flues, serving to regulate the final exit of the heated air, and, being distributed
along the outer length, they do not draw the flame to one part.
The whole interior of the oven, as well as those parts in contact with the flame, must be constructed
of fire-bricks. The main arch, six feet in span and half a brick in thickness, is formed of bricks moulded
on purpose to suit the curve, the joint being kept as close as possible. As this arch is permanent, much
care should be taken in its formation.
93
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A bench of retorts on this plan, if well and regularly used, ought to last from 12 to 14 or even 15
months, and ought never to be suffered to become cold. The first portion of oxide which forms upon
the surface, when allowed to cool, cracks and falls off, leaving a new surface to be acted upon the next
time it is heated.
When it becomes necessary to reduce the number of working retorts on the approach of summer,
those that are nearly burned out should be selected; or, if there are none in this condition, let them
down" very gradually, by keeping the damper closed after the fire is raked out it will be a week before
they become quite cold. The same precaution should be taken in getting up" the heat-opening the
damper gradually.
When a bench of retorts is newly set, the green work must be suffered to get quite dry before any
fire is lighted.
The results of a chaldron, or 36 bushels of Newcastle coal, weighing 27 cwt., distilled in retorts set
in the manner just described, and the quantity of fuel used for the distillation, will be as follows :-
Gas of specific gravity -400 8650 cubic feet. Gas of specific gravity 400. 8600 cubic fect.
Coke of good quality
14 cwt.
Coke
13 cwt. 3qr.
Ammoniacal liquor
121 gallons.
Ammoniacal liquor
121 gallons.
Thick tar
12
do.
Thick tar
111 do.
Tar used as fuel
19
do.
Coke used as fuel
6 cwt.
Lime for purifying
86 lbs.
Lime for purifying
84 lbs.
In country towns, where the quantity of gas made during the winter seasons does not exceed 10,000
cubic feet in twenty-four hours, the retorts must be set singly, as represented in Fig. 1898, the flue
passing beneath and over the retort, which rests upon a half-brick arch, cut flat at the top to receive
it; the end is guarded by a thick fire-tile.
1898.
1899.
TopFlue
Furnaces
When the quantity of gas made in twenty-four hours does not exceed 30,000 cubic feet, or when the
quantity made is decreased 1200 cubic feet at a time, on the approach of summer, the ovens may
contain two retorts, as shown in Fig. 1900. The flues are arranged in a similar manner to those in a
large oven.
1901.
1900.
:-
The Fuel used for heating the retorts may be either coal or coke, according to the relative value of
each in the district. If coal is used, a well-regulated bench will require about 18 to 20 per cent. of the
coal distilled ; that is to say, to heat the retorts for the production of 12,000 cubic feet of gas, from 5
to 51 cwt. of coal will be necessary. The use of coke as fuel is general in those places where coal is
valuable, and where coke is less in requisition as fuel for manufacturers. The quantity of coke for
heating the retorts will vary from 40 to 45 per cent. of the quantity produced; that is to say, from 16
to 18 bushels of coke are requisite to distil one chaldron of coal, or 5 cwt. will distil one ton.
Mr. Croll has introduced a system of using the coke as fuel while red-hot. The charge from the re-
torts is drawn into a wrought-iron carriage, and immediately taken to those furnaces which require
feeding. The saving effected by this simple process is equal to 10 or 12 per cent. The reason is
evident; because when a quantity of black coke is thrown on the previously-heated mass of fuel, the
flues will to a certain extent become cool, since the heated air is absorbed. When hot coke is thrown
on, no absorption takes place, and the flues are kept up at a uniform temperature.
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The use of tar as fuel has of late become frequent, and is the most economical, as far as it is availa-
ble. In almost every instance it is worth more to burn than to sell. The quantity required for car-
bonizing a chaldron of coal varies from 24 to 27 gallons.
The furnace used for burning tar is the same as that used for
other fuel, and is fed by a small continuous stream, conducted by
a wrought-iron service-pipe, from a tank placed on the top of the
1902.
retort-benches, on to a sheet-iron spout projecting a few inches
outside the furnace-plate, and into the furnace itself, as shown in
Fig. 1902, were it spreads over a "breeze-bottom," previously
brought to a red heat.
When retorts have been at work for some months, their
interior surfaces become incrusted with a hard carbonaceous
deposit, approaching, in some of its properties, to plumbago; in
process of time carburet of iron and the more infusible parts of
the coke form a thicker crust, which it becomes necessary to re-
move, both to prevent the destruction of the retort, and to allow
the fuel to have full effect upon the coal contained within. This
was formerly effected with great difficulty by crowbars, the
force required often increasing the evil it was intended to remedy.
It was afterwards found. that leaving the retort open, and allowing cold air to come in contact with
the heated interior, the deposit contracted, and could be broken away in about twelve hours without
danger to the retort.
In order to take off this crust without endangering the retorts, an air-blast is used, as follows :-A
cast-iron pipe, about three inches in diameter, is carried along the front of the benches, at a little
distance above the upper retorts; at points in this pipe, directly over every retort, a screw and plug is
attached, into which screw, when the plug is removed, a wrought-iron service, about an inch in
1903.
1904.
1906.
1905.
diameter, can be fixed, and led into any open retort The main pipe is connected with a blowing
cylinder, worked by the steam-engine, 80 that a strong blast can be made to impinge upon any part of
the hard incrustation, which gradually yields to it, and may then be removed without difficulty.
Ear-shaped retort.-Fig. 1903 is a front elevation of a bench containing three retorts
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GAS.
Fig. 1904 is a section taken transversely.
Fig. 1905 is a longitudinal section through the centre of the arch.
Fig. 1906 is a plan of Fig. 1904.
Figs. 1907, 1908, and 1909 are views of a mouth-piece on a scale of t an inch to a foot, which will
show the method usually adopted for securing the lid in all ordinary retorts.
1909.
1907.
1908.
1.0
The great objection to the ear-shaped retort is, that the bottom bends are liable to become filled up
with hard carbon, and when that is the case they are sure to crack. The principle on which they are
constructed is good; and if they could be charged properly, viz. with a stratum of coal from 3 to 31
inches thick, evenly spread over the bottom, they would be found to make more and better gas than
D's and circular retorts, (where the stratum of coal is thicker,) simply because it would be more evenly
acted upon. In all cases, with the same degree of heat, the thinner the stratum of coal the better the gas.
The mode of setting these retorts may be precisely similar to that explained in Figs. 1902 and 1903.
Brunton's patent.-Fig. 1910 represents a front view of a bench of four retorts, upon Mr. Brunton's
principle.
1911.
1910.
B
B
D
D
F
E
LAAI
A A are the retort-mouths, the lids of which are fitted with stuffing-boxes, for the reason to be pre-
sently described, and permanently jointed in their places with iron cement.
B B are hoppers, capable of holding from 20 to 28 pounds of coal, which, when an air-tight slide-
valve C is drawn back, falls into the retort through the neck D: the valve is closed immediately.
1912.
B
D
K
G
F
H
R
E is the furnace, projecting beyond the face of the brickwork in which the retorts are set.
F F are handles for working a piston contained in the mouth-piece A.
Fig. 1911 is a transverse section of one half of a bench. The retorts G, shown as circular, may be
varied in form if thought necessary. We believe the patentee gives thepreference to those of a D shape.
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E is the furnace; the direction of the flues is shown by arrows.
Fig. 1912 is a longitudinal section through the centre of the furnace.
H is a short pipe, open to the interior of the retort, sealed at the lower end by dipping into water,
through which, after a charge is thrown into the retort from the hopper B, a portion of coke is expelled,
by advancing the piston contained in the mouth-piece.
1914.
I
1913.
6
и
H
E
I is the pipe by which the gas, as it is formed, passes to the hydraulic main.
K is a bonnet, to be taken off at any time when required to examine the interior of the retort.
Fig. 1913 is a back view of Fig. 1910.
Fig. 1914 is a plan below the retorts. (The same letters refer to corresponding parts in all the
figures.)
1915.
The annexed diagram, Fig. 1915, will explain
the construction of the piston before alluded to.
a is the piston, drawn back in the proper po-
sition to receive a charge, which, when the slide-
valve is opened, will fall into the space b, and be
propelled forwards into the heated part of the re-
tort by turning the screw c, which works in a nut
d on the back of the piston.
e is a collar upon the shaft of the screw, work-
b
ing between the bottom of the stuffing-box and a
washer held in its place by four pins. The stuf-
fing-box is made tight in the usual way, by screw-
ing the gland f against a gasket.
g is a shield loosely attached to the front of the piston, to prevent the accumulation of small coal-
dust in the mouth of the retort. When the charge is thrust forward, the piston is turned back directly
into the mouth, to preserve it from the action of the heat.
That part of the retort adjacent to the flues only is heated, consequently the only part liable to much
wear and tear.
The only part requiring renewal is that of the retort situated between the outer walls of the bench,
and weighing about 9 or 10 cwt. The fuel required to carbonize the coal is about 25 per cent. in coal
on the quantity distilled.
Reciprocating retort, the invention of Mr. George Lowe.
It has been stated that the first portion of vapor produced by coal when undergoing destructive dis-
tillation in ordinary retorts will, when converted into gas, form that of the most brilliant quality, and it
is to effect this that the following arrangements have been patented.
Fig. 1916 is a back elevation of two pairs of retorts. A1, A3, Aᵃ, A' are the retorts; BB the stand-
pipes; CCC, slide-valves for opening and shutting off the communication between the retorts and
hydraulic main; D is the hydraulic main. The front elevation differs but little from it.
Fig. 1917 is a plan of the lower pair of retorts; the operation is as follows:-Supposing the entire
bench to be at the requisite heat for decomposing the coal, and that they are working six-hours' charges,
the lids of the retorts A' and A' are removed, and by means of scoops (each half the length of the
retort) the coal is introduced at both ends, and the lids immediately secured in their places: the slides
F' and F' are opened, and C' and Ca closed. The bituminous vapors that rise first will pass through
the pipes EE, and thence through the entire length of the hot retorts A2 and A', and be converted into
gas, which will pass to the hydraulic main by the stand-pipes on which the slide-valves Cs and Cª are
fixed, and which remain open. When the distillation has gone on for half the duration of the charge-
viz. three hours-the valves C' and C' are opened, F' F' shut, and the gas evolved from the retorts A'
and A' passes through the stand-pipes attached to them. The retorts A2 and A' are now charged, the
mouths closed, the valves F' and F' again opened, and Cs and C4 shut. The operation is now reversed,
the first vapors passing through the two first-charged retorts until their charge is expended, when C2
and C' are opened, F' and F' closed, and the charge drawn. They are then immediately recharged,
and the operation of opening and closing the valves repeated.
Retorts on this construction have been worked, and are found to act well, producing gas of average
quality and in greater abundance than by the ordinary method. The reason of the gas being only of
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GAS.
an average quality is, that the carburetted hydrogen made after the production of bituminous vapor has
ceased, still passes over the red-hot surface of another retort and deposits some portion of its carbon,
the rich gas formed by the conversion of the bituminous vapor only serving to make up the deficiency.
1917.
c⁴
C°C¹
8
D
1916.
B
B
E
A4
As
At
A2
E
E
As
A4
E
E
F2
If, instead of having only two retorts in a set, the number could be increased to six, and after the
first hour the gas be allowed to pass away on the ordinary plan, both the quantity would be augmented
and the quality improved.
Revolving web retort.-This retort is arranged 80 that the coal is acted upon in a thin stratum and
converted into gas at once: the chemical advantages of this method are many ;-all the elements of
the coal are liberated at nearly the same time, and unite with one another in such proportions as to
form gas of the best illuminating quality, and in greater abundance than when the coal is carbonized in
mass. The condensed bituminous vapor which forms tar in the ordinary process is by this nearly all
converted into olefiant gns.
1918.
a
C
G
Brich Rnbble
D
M
Fig. 1918 is a longitudinal section through A B in Fig. 1920.
Fig. 1921 is a transverse section through CD in Fig. 1918.
Fig. 1919, plans of the retort in section, over the top of the retort, the web, and furnace,
respectively.
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The same letters refer to corresponding parts in all the figures.
E is a hopper containing the coal; F is the discharging-disk; G is the retort; H is a web on to which
the coal is discharged by the disk F; II are revolving drums carrying the web H; K is the furnace;
LL the flues passing under and over the retorts, and finally into the main flue; M the shoot into which
the coke falls; the end of which may either dip into water or be furnished with a tight door.
The retort itself, and the cham-
ber in which the drums work,
are made of wrought-iron boiler-
plates, riveted together 80 as to be
1919.
quite gas-tight. The only parts
subject to wear and tear are the
retort adjoining the flues and the
web, both of which are heated;
G
F
the latter however never becomes
so hot that the shape alters. The
action of this arrangement is as
follows :-
All the coal must be either
ground, or beaten small and
H
screened, so that no lumps re-
main larger than coffee-berries,
and a twenty-four hours' charge
must be thrown into the hopper
and secured by a luted cover.
The discharging-disk, which is
nine inches in diameter, with six
arms, is made to revolve uni-
formly with the drum below it, at
the rate of four revolutions an
hour for this purpose two shafts
run the entire length of the retort-beds, on one of which the drums are fixed; on the other are the dis-
charging-disks, connected at one end by a strap. The diameter of the hexagonal drums is so regulated,
that the coal which falls on the web from the discharging-lip will at one revolution have passed the
entire length of the retort. Fifteen minutes is quite time enough to convert the coal so distributed into
gas. Each link of the web is 14 inches long and 24 inches broad, having a surface of 336 square inches,
upon which the contents of one partition of the disk will be discharged, viz. a little more than 124 cubic
inches of coal in a stratum less than three-eighths of an inch thick. Each successive link receives the
same quantity, so that, in one entire revolution of the disk and drum, 745 cubic inches of coal (equal to
21 pounds) are distributed over a heated surface of 2016 square inches, and converted into gas.
Eighty-four pounds of coal will by this process make 450 cubic feet of gas of the specific gravity 490.
It therefore follows, that in 24 hours 18 cwt. of coal will be discharged by each retort, making 10,800
cubic feet of gas, equal to to 12,000 cubic feet per ton.
1920.
1921.
d
G
I
Is
K
B
M
These retorts are considerably more expensive in the first instance than those in general use, but in
the end they would be found cheaper. Indeed, the entire arrangement is one of great economy, and by
far the most scientific process yet adopted for making coal-gas; it requires no attendance, except that
of keeping up the furnace and charging the hopper once in twenty-four hours. No gas is lost, and no tar
made. The coke produced is increased in quantity by about 75 per cent., but its quality is not 80 well
fitted for general purposes (although superior for culinary uses) as that produced by the common process.
The power employed for turning the shafts may be A water-wheel which would be preferable to a
steam-engine, unless in large works, where the latter could be employed for other purposes. An overshot
wheel, six feet in diameter and nine inches in breadth of float, would drive twelve retorts at the speed
required; the water for turning such a wheel for twelve hours may be pumped up by two men in about
an hour and a half. This form of retort is in first cost more expensive than others, but it is believed to
be in the end more economical.
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The quantity of gas produced by five D retorts, such as are shown in Fig. 1892, will be about
14,000 cubic feet in twenty-four hours, of specific gravity 390 or 400, and the quantity produced by
four of the proposed retorts will be 43,200 cubic feet in twenty-four hours, of the specific gravity .470
or 490.
All the machinery, except the retorts and webs, will last for years without any repair, except what
may arise from contingencies, to which all machinery is subject.
Earthen retorts.-In speaking of clay or earthen retorts, it is necessary to limit our remarks upon
them to the results of practice; for in many instances, owing to actions not entirely and clearly ac-
counted for, the results given by these vessels differ from those which theory in its strict sense would
admit as being correct.
One practical point must be observed, that clay retorts of small dimensions are less economical than
those of larger size, owing to the great per centage of fuel required to keep them at a proper tempera-
ture for decomposing the coal. The advantage of using the latter description of distilling vessel is sim-
ply a question of profit and loss, or whether it is cheaper to burn iron or coal. The material of which
they are formed is a non-conductor of heat, consequently the absorption of caloric is less rapid; and
although they retain their heat when a fresh charge is introduced better than iron retorts, yet not
sufficiently to bring down the quantity of fuel as low as that required for metal. Notwithstanding this,
even small clay retorts are preferred in many places, particularly in Scotland. Mr. James Reid, of the
Montrose Gas-works, has favored us with the following description of his earthen retorts:
1922.
D
D
D
e
so
" We have had clay retorts in operation for the last three years, and from the great difference in
price, compared with that of iron retorts of the same size, and from the immense superiority over metal
in working them, we have entirely given up the use of the latter. I tried the clay retorts in the shape
of an ellipsis, in the D and circular form. The size I find best adapted to all purposes is eight feet long,
fourteen inches diameter, and four inches thick: such a retort costs £2 6s. ; the pillars or columns for
supporting them are 6s. each, and each retort finished costs £3 48. The mouth-pieces are cast metal,
and fastened to the end of the retorts by bolts and flanches, as in the ordinary description, and jointed
with fire-clay and iron cement. The retorts are made in two lengths, and are jointed by a body of fire-
clay well diluted with water. The most economical plan for erecting them is to set them, three under
one arch, heated by one fire. Their only drawback is, that when the heat is let down they contract
unevenly on cooling, and are liable to leak when again required for distillation; they generally last two
years."
Clay retorts have been used for some years at Wolverhampton with success. The retorts are circu-
lar and made in joints of 32 inches long. In several places these retorts are made at the works.
The reader will fully understand their plan of construction from the elevation and sections. Trans-
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745
verse section and elevation, Fig. 1922, and Fig. 1923, longitudinal section, which require no description, ex-
cept that the bottom is exposed directly to the heat of the fire, and is slightly cambered," or curved up-
wards, to enable it with more certainty to retain its form. The cement with which the parts of the
oven are jointed is a composition the ingredients of which are not known, but seems to be an excel-
lent substance, and when the interior is coated with it, becomes vitrified and quite gas-tight under con-
siderable pressure.
In England and Scotland the fire-clay retort has superseded the use of metal in no less than forty
towns; in some instances it has lasted for the extraordinary period of twelve years. The oven or
D-shaped retorts are found to be the most advantageous, being made with a capacity to carbonize one
cwt. of coal every hour. They can be constructed either to be heated by coke ovens, or coke furnaces,
or by the burning. of tar: with coke ovens they are more durable. It appears that clay retorts, when
constructed upon such a scale as that given in Fig. 1922, have great power to retain their heat when
brought to the proper temperature for decomposing the coal, viz. 27° of Wedgewood, and the intro-
duction of a fresh charge is not nearly so much felt by them as by metal This power of retaining heat
is proved by constant practice to produce 1000 cubic feet of gas per ton from the same coal more than
the average of the London produce, and the consumption of fuel is not more than 22 or 23 lbs. of coke
to carbonize 100 lbs. of Newcastle coal, taking the average of six months' working.
1923.
A)
B
When properly constructed, these retorts are not in any degree liable to fracture or to the escape of
gas, but are of such strength as to resist the greatest pressure which is likely to be put upon them.
The coke also made by them is invariably of better quality, and produces less breeze or waste.
Oil gas.-It appears, at first sight, both inexpedient and superfluous to distil oil for the production
of gas, when we consider that oil can be burnt in lamps without any further preparation, whilst it
loses carbon by deposition in the retorts. Purified lamp-oil is consequently never used but gas can
be prepared from impure oils, train-oil, or refuse fat, with as much ease as from the purer kinds. The
manufacture of gas is, therefore, under certain circumstances, an admirable means of using up such
materials for the production of light, as could not otherwise be employed, or only applied to the lowest
uses. The experiments of Henry, which extend also to this part of the subject, show at once the plan
that must be adopted upon a large scale. His results are given in the table in the following page; from
which it appears that oil gas is superior to that obtained from coal, as is also shown by its density,
and that the produce, dependent chiefly upon the temperature, is of the best quality when obtained at
a low red heat. This temperature suffices to convert the oil into gas, but is not sufficiently high to
decarbonize the gas to any great extent. The apparatus for obtaining gas by the distillation of oil is
represented in the following drawing, Fig. 1924. To accelerate the evolution of gas, and shorten the time
which the gas already produced has to remain in the red-hot vessel, the retort a is filled with bricks, or
94
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lumps of coke, which extend the red-hot surface very materially. The second cylinder b, serves both
as reservoir and hydraulic main at the same time, and, with this object in view, a and b are connected
in two places d and g. Oil flows from a large cistern above the apparatus in a constant stream through
the tube c to b, which b is thus kept filled up to a certain level. From b the oil descends through e to
a, is converted into gas and tar, returning through d to b. The tube d makes a short bend, and just
enters below the fluid level in b, so that the vapors of the decomposed oil must constantly pass through
the reservoir of oil, and deposit their tar. The retort a is, therefore, constantly supplied, not only with
oil, but with a mixture of oil and tar, in such a manner, that all the condensed products return to the
1924.
b
retort together with a fresh quantity of oil, until they are completely converted into gas. If the ex-
periment is made in a long tube, inclined at the hinder part, whilst the front is kept cool, hardly any
tar will be produced. The gas which collects above the oil in b, passes on through the tube g. As the
objections raised in the case of coal gas do not here occur, cast-iron retorts are solely used in oil gas
works, with the same firing in other respects, r being the grate. According to trustworthy statements,
1 cubic foot (= about 4 gallons) of oil produce 600 to 700 cubic feet of gas, which is equivalent to from
90 to 96 per cent. by weight; the remainder is carbon, which is deposited between the coke or bricks,
and some unavoidable loss. The production of oil gas is a continuous process, and thus differs from the
distillation of coal. The retorts only require opening now and then, for the removal of the deposit of
graphite. Vapors of the same composition and properties are found in oil gas, as in coal gas. Thus,
according to Hesz, all the volatile empyreumatic oils, which occur mixed with each other in tar from
oil, have the same composition per cent. as olefiant gas. Faraday had previously observed in England,
where oil gas was compressed for technical purposes with a pressure of 30 atmospheres, that these
vapors were condensed to a fluid, of which 1 part occupied the space of 7500 parts of gas.
Substances
Temperature of the
Specific gravity
of the gas.
Absorbed by
chlorine.
Light
carburetted
hydrogen.
Carbonic
oxide.
Hydrogen.
Nitrogen.
distilled.
Distillation.
In 100 parts of illuminating gas.
Bright red heat
0.464
6
28.2
14.1
45'1
6·6
Oil
Ditto
0.590
19
32.4
12.2
324
4
Lowest possible temperature
0.758
22.5
50.3
15.5
7.7
4
Train-oil
Low red heat
0-906
38
46.5
95
3
8
Resin gas.-If resin (colophony) were usually fluid, instead of being solid, there would be no differ
ence in the mode of obtaining gas from it to that practised in the oil-gas manufacture; as this, however,
is not the case, it becomes necessary to render the resin fluid by some suitable means, that it may be
easily supplied to the retort. The volatile oil from tar is frequently used for this purpose.
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The flame from the retort fire, before escaping by the chimney, is caused to heat up a vessel con-
taining resin. As this melts, it trickles through a sieve, into the second division of the vessel, leaving
the impurities and the solid portion behind, where it is mixed with an equal part of the oil of resin (tar).
Thus a solution which will no longer solidify is obtained, and with it the retort is supplied, as with oil
in the former case. When the gas has parted with its condensible vapors in the coolers, it is in a fit
state for consumption, no further purification being required, as is likewise the case with oil gas.
One of the best arrangements for resin gas, and which has stood the test of practice, is that which
has been extensively carried out by Chaussenot, and is shown in Fig. 1925; the resin is here melted
by itself, and the oil of tar collected and disposed of as a secondary product. The draught to the fire-
place P is regulated through the ash-pit by means of the plate Q, which can be moved horizontally
backwards and forwards in the groove h. The air passing from below through the grate r r, and the
fuel, creates a powerful flame, which passing, in the first instance, through the apertures in the
roof, plays round the retort A, in the space M, and then, before reaching the chimney, heats the vessel
I, containing the resin, by means of the flue NN. If this vessel requires filling, the fire is shut off from
N, by the damper b, and is allowed free egress at the aperture 0, by drawing back the damper c.
Both the dampers are worked by iron rings and rods from without. In Chaussenot's apparatus, it is not
necessary to dissolve the resin in tar-oil, because the vessel I, in which the resin is melted, and the
conducting tube H, being constantly surrounded with hot air, no solidification of the melting resin at
the bottom f need be apprehended. Combustible gases are generated by merely melting the resin,
which may possibly endanger the whole apparatus. To avoid such contingencies, the edge of I is fur-
nished with a groove filled with water и и. into which the lid K dips at v v, and is consequently secured
by a water-valve. By means of the appendage y, the vapors can be conducted into the chimney, or
under the grate. The melted resin flows consecutively through H G and x, into the retort A. Between
1925.
Ga
G and H is a plate o, with a funnel-shaped aperture in the middle, in which the conical end of the rod
d is movable. If this is raised through the stuffing-box e, the retort A receives a larger flow of melted
resin ; if it is pushed down the stream diminishes, or the flow ceases entirely. The resin flowing from
x is carried to that part of the retort containing the coke, by means of the inclined plate g. The coke
is prevented falling into the neck of the retort by the grating 1; here, too, the gas escapes through a
tube downwards to the tar cistern C, and from thence through E to the cooling pipe D, which is im-
mersed in " ater in a long trough P. C is constantly nearly filled with tar, that the mouth of to may
always rem n immersed; this, therefore, dips into C, whilst the gas-pipe E, behind the sectional level
in the draw H. only just passes through the material of the main C. The neck F. situated above x, has
a small appendage a'; this, as well as a" and a", is constantly immersed, and all three are used only
for introducing iron rods in cleansing the approaches to the retort; a is a similarly constructed appen-
dage for screwing up the lid of the retort; a a' a" and a"" are all furnished with iron semicircles and
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GAS.
screws, for forcing iron plates flat against the apertures. In such a furnace, therefore, distillation goes
on continuously, until the deposition of carbon renders a renewal of the coke necessary. Resin gas is
not 80 highly illuminating as oil gas, and is of about the same quality as coal gas; it is used in many
towns, as in Frankfort-on-the-Maine, Antwerp, &c. 14 to 23 cubic feet of gas are obtained from 1 lb.
of resin.
Gas from soap-roater.-Few cases are adapted to give 80 favorable an idea of the practical value of
gas illumination, as the process carried out at the works of Houzeau Muiron, at Rheims, where very
good gas is obtained from refuse which previously cost something to throw away, and which now is a
source of profit to the manufacturer. This refuse is the soap-water, in which woollen stuffs have been
freed from fat. Besides the unchanged fat with which those goods are charged as they come from the
loom, the soap-water contains a solution of oleate and stearate of soda, and compounds of the same
acids with lime in suspended flakes, and lastly, animal matters extracted from the wool. From all parts
of the town the soap-water is collected, and brought to the reservoirs of the works, where 300 cwts. at
a time are treated with 2 per cent. of sulphuric acid, (or twice as much hydrochloric,) mixed with equal
parts of water. After the lapse of 12 to 18 hours, complete coagulation is effected. The water contains
Glauber's salt (sulphate of soda) in solution; a little gypsum is formed at the same time, and an impure
gray fatty matter rises to the surface. This consists of the fatty acids, oil, and animal matter with
much water the greater part of the latter has already been mechanically separated, and the remainder
is removed by melting in copper vessels; the contents are then drawn off into a second boiler containing
some sulphuric acid to effect a clarification. The filtration which follows affords a clear oil, and this
gives with crude soda (containing sulphuret of sodium) a very tolerable soap, whilst sulphuret of iron
separates, together with a black solid residue, containing much fat for distillation in the gas retorts.
The process of distillation is like that practised with resin: the tar produced the first day is used on the
morrow to dissolve and render fluid the solid residue, and 80 on. The ohm (= about 30 gall.) of soap-
water costs 28 kreuzèrs, about 18 cents.)
Gas from animal matter.-In the distillation of animal matters, bones, flesh, &c., as it has long been
practised for the production of bone-charcoal and bone-black, tar (stinking oil, Dippel's animal oil) and
gases are generated. The illuminating power of the latter has latterly attracted the attention of man-
ufacturers. Seguin, in particular, has carried on the process on a large scale, making use of the gases.
The material, for instance, the flesh of dead animals, contains 60 per cent. of water, which must be re-
moved by drying before being placed in the retorts, and the latter should be kept at a cherry-red heat.
The sulphur (a constituent of albumen, fibrine, &c.) is chiefly found in the gas as sulphuret of carbon,
the nitrogen of the flesh as carbonate of ammonia. After being properly cooled, the gas is first passed
through a solution of chloride of calcium, where carbonate of lime and sal-ammoniac are formed, and
from thence through tubes containing lumps of sulphur, which condense the sulphuret of carbon to the
fluid state, and dissolve in it. The latter would be converted in the flame into sulphurous acid and
carbonic oxide.
Retort-house.-The adjoining cut, Fig. 1926, represents a retort-house built of brick, for coal gas, upon
the most simple construction, and well adapted for a town requiring 70,000 cubic feet of gas for the
supply of each night in the winter season. Being without coke-cellar, the charges must be drawn into
wrought-iron barrows, the contents wheeled into the open air and spread abroad to cool
1926.
arche
open arches
a
a
reforts
ground
line
The outside walls are calculated to give the greatest security with the least possible material. The
piers a a are 18 inches thick at the base, projecting 41 inches (on the outside) from the brickwork filling
the space between them. Half way up the walls there is a 41-inch offset, which leaves the thickness
of the panels 14 inches below, and 9 inches above the offset.
The roof is of wrought-iron; the ventilator is of wood.
The retorts were set five in one oven, making forty retorts, which will allow two extra benches for
repairs.
In twenty-four hours, thirty working retorts will carbonize 240 bushels, or 180 cwt. of coal, and pro-
duce 78,000 cubic feet of gas. In some places, where little gas is required in the summer season, one-
half or even the entire number of retorts may be set three to one oven with economy.
In the example, Fig. 1927, advantage was taken of sloping ground to form a coke-shed, which saved
a considerable quantity of brickwork. The charge, as it was drawn, fell through the space in front of
the retorts, and was carried by an inclined plane into the shed behind.
This house is considerably larger than that described in the last example, and is furnished with a
coal-store. It may perhaps be as well to state here, that coal from which gas has to be distilled should
if possible be always kept under cover, because, when moisture is present, the hydrogen arising from
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the decomposition of water will deteriorate the quality of the gas. It is, therefore, a matter of econ-
omy to construct a sufficient shed to preserve the coal in a dry state.
The house contained 55 retorts, allowing two benches of five retorts each for repairs. The coal car-
bonized by the remaining 45 retorts was 360 bushels, or 270 cwt. in twenty-four hours, producing
117,000 cubic feet of gas.
The cost of these buildings will depend upon the price of brick, lime, labor, &c., and will vary in
different localities.
Chinineys.-The draught absolutely required for the proper combustion of the fuel beneath the
retorts is little; indeed, that usually given to a common coke-oven would be sufficient. It is necessary
to build a high chimney, however, to carry off the smoke, which, if not allowed to spread, would become
a nuisance to the neighborhood. The height of a chimney does not decrease the quantity of smoke, but
distributes it over a larger surface and causes less inconvenience.
To obviate the excess of draught, it is advisable to
1927.
make an opening into the shaft communicating with the
ventilator
external air. The dampers of the retort-flues might be
used to adjust the draught, but this would be relying too
much upon the workmen. It often happens, if there is
no check, that during the night the heat of the ovens will
be neglected, and suffered to fall below the proper tem-
open
arches
perature; and then, to make up, the dampers are opened
and the furnaces forced, to the deterioration of the retorts,
the waste of fuel, and the production of inferior gas.
When there is an air-opening into the shaft this cannot
be done, and there will therefore be less danger from
such carelessness.
coal store
With this precaution, the chimney may with advantage
be built seventy feet high, even for a small number of
retorts; but the height of the shaft must always be regu-
lated by the description of property surrounding or in the
vicinity of the works.
Purifiers.-The gas, when it leaves the reforts, retains its impurities, and in this state is quite unfit
for illumination. The impurities are bituminous vapor, ammoniacal gas, essential oil, and sulphuretted
hydrogen; the processes adopted for removing these are partly mechanical and partly chemical. The
first operation is the condensation of the volatile portions, which is effected at different places in differ-
ent ways. The condensers generally adopted either consist of a series of pipes arranged in the manner
of a distiller's worm, or of a number of chambers contained in a tank, and surrounded by cold water;
at the lowest points of these vessels siphons are attached, sealed by dipping them into tar to a sufficient
depth to prevent the gas from escaping, and through them the condensed bituminous and ammoniacal
vapors pass away to the cistern constructed to receive them in the forms of tar and ammoniacal liquor.
The same tank serves to contain both, the difference of their specific
gravities keeping them separate; the ammoniacal liquor, being the
1928.
lightest, swims on the surface of the tar. The tank is generally sunk
below the surface of the ground; the respective heights of the two
fluids are registered by floats and gages, and, when found necessary,
are pumped out. If there be no sale for the tar, it is burned beneath
the retorts, and the ammoniacal liquor is either evaporated in the
cast-iron pans placed under the furnaces for that purpose, manufac-
tured into the carbonate and muriate of ammonia, or used as manure.
The simplest and best condenser is formed of a few upright pipes.
Their number and length being regulated by the quantity of gas
required to pass through them, ten feet run of pipe for every 10,000
feet of gas is ample; in height they may be equal to that of the wall
of the retort-house, for the convenience of placing a tank on the roof
to supply them with water. At the bottom of each bend is a siphon,
similar to that represented in the annexed woodcut, by which the
condensed vapors before mentioned are conveyed to separate vessels,
the fluids passing away being of different values, (that from the last
siphon is the most valuable.)
These pipes must be kept wet in warm and dry weather by small
streams of water running on to them from a tank placed at the top
of the retort-house. The quick evaporation of this moisture will
keep the pipes much colder than if they were completely immersed
in water. If after condensation 'dry lime" (the term dry lime" is
used in contradistinction to lime-water, the tirst being simply a
hydrate, the latter holding lime in suspension with a large quantity of fluid) is used for purifying, the
gas must pass through a wash-vessel, that a portion of sulphuretted hydrogen may be absorbed before
the gas comes in contact with the lime in the purifiers; and to effect a final separation of the ossential
oil, ammoniacal and carbonic acid gases, the essential oil is 80 intimately mixed that it may be detected
in gas after it has passed through a pipe a mile long. (Its presence may be proved by shaking the gas
with a little alcohol contained in a bottle; the oil will unite with the latter, forming a soapy liniment.)
A wash-vessel is shown in Figs. 1929, 1930, and 1931 : A is the inlet pipe for the gas, which displaces a
column of water about three inches high, and passes first through the openings 666 and at the sides of
the wrought-iron box B, then through the continuous opening or slit C C, (which must be equal in area
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to that of the inlet and outlet pipes, viz. in this example, 50-265 square inches, the diameter of the pipes
being eight inches,) and finally through the water. The use of the opening CC is to divide the gas into
small portions and distribute it over a large surface. The more minutely it is divided, the better will
the wash-vessel effect its object.
D is the outlet-pipe.
E is a siphon, for maintaining the water at a certain level; the part which enters the tank is con-
ducted to the bottom, in order that the sediment may run off. The upper end of this dip-pipe is open,
or it would otherwise form an actual siphon and drain the tank.
F is a portion of a condenser, called by workmen a gridiron condenser," which, when separators are
used, may be dispensed with.
1929.
B
B
1930.
B
B
After this last process, the gas is in a state to come in contact with the dry or hydrate of lime to be
purified, which is much the best for that purpose, as it is attended with less nuisance, less pressure,
(which is also of importance,) and the sulphur which has united with the lime may be sublimed from it
by putting the spent lime from the machine into burnt-out retorts kept at a heat just red by daylight,
with the refuse coke-dust and cinders, for which there is no sale. The sulphur thus produced is a mar-
ketable commodity. The larger the surface of dry lime to which the gas is exposed the better for if
it be allowed to pass through the stratum with much velocity and in an undivided stream, it will work
a passage in such a way that a great bulk will not be purified
1931.
at all, for of course it will pass through that part where it
meets with the least resistance from this not having been
understood or attended to, many superintendents have aban-
doned the use of dry-lime purifiers. The quantity of lime
required for purifying coal-gas by the above process will
depend upon the quality of both the lime and gas. One
bushel of quick-lime will suffice in some places to purify
10,000 cubic feet of gas, while in others twice that quantity
will hardly serve. By being slacked and reduced to a proper
consistency for use, its bulk will be more than doubled ; two
bushels of this hydrate will spread over a surface of 25
square feet, 21 inches deep, which is about the thickness
found in practice to be the best.
In Figs. 1932 and 1933 are represented an elevation and plan in section of one of a series of three
" dry-lime" purifiers, through which the gas passes successively; in other words, they are " worked to-
gether," and, though separate, may be considered as one machine.
A is the inlet pipe from the wash-vessel, entering at the bottom of the first purifier.
B is a plate of sheet-iron, about two feet square, placed over the mouth of the inlet-pipe, to separate
the stream of gas in some degree, as well as to prevent any lime from falling into the pipe.
CCC are the layers of hydrate of lime, spread upon screens formed of an outside frame, and a num-
ber of round rods or wires about 5-16ths of an inch in diameter, stretched across them in one direction,
to afford greater facility for clearing, with a small interstice between each. These screens are placed
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one over another, in three tiers, from six to eight inches asunder; each tier may consist of four screens,
for the convenience of lifting them out and replacing them.
D is the outlet-pipe leading to the second purifier. This arch-pipe is made of thin plate-iron, sealed
at each end by a water-joint; because, when the lid has to be lifted, this arch-pipe must be removed,
and any other kind of joint would be troublesome.
E is the lid of the purifier, also sealed by a water-joint: e e are round 5-8ths rods, keyed at one end
into the keep-ring k, and riveted to each corner of the lid at the other; a chain is hooked on to the ring
k, and passed over a pulley to a balance-weight, by which, and the rods just mentioned, the lid is lifted.
F F are blank flanches or bonnets, through which, when removed, the pipes are cleared from any de-
posited impurity.
1932.
F
D
G G are clamps, to keep the lid of the purifier in its place.
A is the pipe leading from the wash-vessel into one partition of the hydraulic valve, which shall be
described immediately.
B is the pipe leading to the three purifiers CD E in action, and rising into the same partition of the
valve as B.
F is the pipe leading the purified gas back to another partition of the valve.
1933.
E
A
D
G
G is the pipe conveying this gas to the meter and gasometers; the connection between the two last-
named pipes is formed in the same way as that between the pipes A and B. It will be evident that
the lime contained in the first purifier will be spent or saturated before the other two, and that con-
tained in the third will be comparatively untouched. At the expiration of twenty-four hours CD and
E must be shut off, by changing the divisions of the hydraulic valve to the situation shown by the dotted
lines in the figure representing that valve, and turning the gas through HIK, having previously been
put in readiness; at the instant of turning the valve the gas will pass through both sets of purifiers, all
the communications being open.
When the covers of CD and E are taken off, remove the screens from C, and place those from E in
their stead. The lime from C is quite expended, and must be either heated to sublime the sulphur, or
laid aside until it can meet with a sale as manure, or be otherwise disposed of. That from D may be
spread for a time in the open air, (if there be room in the works,) and in a week or two it will be fit to
use in the first purifier. After renewing the lime in the second and third purifiers, replace the covers,
and they are again ready for action. The same operation is repeated when H I and K are spent.
Fig. 1934 represents the hydraulic valve just mentioned.
A is a cast or sheet iron tank, three feet diameter and two feet six inches deep, generally filled with
tar to within six inches of the top.
B is a light sheet-iron or tin gasometer-shaped vessel of less diameter, divided into three partitions
by the plates CD and E, of less depth than the rim.
F is the pipe from the wash-vessel or condenser.
G is the pipe leading to the first set of purifiers.
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GAS.
H is the outlet or return pipe from them.
I is the pipe leading to the meter and gasometers. These pipes, in the present position of the valve,
are all in action.
F and G, being in the same partition, communicate with each other, as do H and I, for the same
reason. When the purifiers have to be changed, the vessel B is lifted up, until the bottom of the par-
tition, at C in the elevation, Fig. 1933, clears the pipes, the outside rim remaining immersed in the tar,
(the stops S on the guide-rods prevent it from being lifted too high,) and turned partly round until it
occupies the position shown by the dotted lines in the plan, Fig. 1934}. The length of each dot N
through which the guide-rods M pass, mark this position and effectually prevent mistakes, for the vessel
cannot be turned the wrong way.
1934.
K and L are the pipes connected with the second set of
purifiers thrown into action and into communication with F
and I, when the vessel B is shifted to the position shown by
the dotted lines in the plan.
P is a wooden frame supporting the pulleys and bal-
S
S
ance-weight Q to assist in lifting the vessel B, which, while
Q
in action, is kept from rising with the pressure of the gas
by a bolt.
P
In preparing the lime for the purifiers, it ought to be
beaten, well sifted, and water added, until, by compression
B
in the hand, the lime will just adhere; if any lumps re-
main, their outside only will be acted upon; when broken,
they will be found untouched in the inside; and although
such lumps may be used again, it is always better to sys-
temize the process in the first instance, and prevent even
the smallest waste.
Lime-water purifier.Fig. 1935 is an elevational section
of a lime-machine, and Fig. 1936 a plan through a b in
Fig. 1935.
A is the inlet-pipe through which the gas passes into
the chamber B, which is four feet diameter, jointed to the lid
K
G
of the purifier, and supported upon two cast-iron beams C.
On to the bottom flanch of this chamber a circular ring of
thin wrought-iron plate is riveted, of such diameter that its
outside rim will be within five inches of the tank of the
purifier.
D is a hoop supported from the tank by bolts dd, etc., having its upper edge level with the before-
named plate, and its lower edge four or five inches below it. The space left between this hoop and the
ring is three-eighths of an inch, through which the gas (after having overcome the pressure of the
column of water contained in the tank, plus the pressure in the gasometers) will pass, and bubble up
through the lime-water.
E is an arm made to revolve on the spindle S: the parts e e of this arm continue through the aper-
ture and over the ring, serving to keep the lime from settling or obstructing the passage of the gas.
F is the outlet for the purified gas.
G is a stuffing-box, through which the spindle S passes.
H is a miter-wheel, connected to a water wheel or steam-engine for turning the spindle.
1935.
19341.
F
G
K
B
Lime
H
E
L
b
a
N
I
I is a pipe, through which the lime-water is drawn off when it has become saturated with the im-
purities of the gas. It will be observed, that by this contrivance the water can be completely drained
off, by opening a slide-valve bolted to the flanch of the pipe K, without suffering the gas to escape
along with it, because a column of water will remain in the tube I equal to the height of the bottom
of the tank, measured from the inner radius of the curve of the tube, viz. twelve inches, which is always
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more than sufficient to overcome the pressure of the gas in the purifier when the valve on the inlet-
pipe A is closed, which should be done before that at K is opened.
L is a cylindrical vessel, open at the top, for filling the purifier; it also serves to show the quantity
of water required; when the machine is at work the column contained in the vessel will be as much
higher than that in the tank, by the pressure of gas in the gasometers, usually about three inches.
The lime-water may be mixed in a cistern, and drawn off by a hose into any of the machines, care
being taken to keep the mixture well agitated while passing. The proportions are one measure of
paste-lime to three of water; that is, to every five bushels of paste-lime about 120 gallons of water
must be added. The size of the lime-machines ought to be 80 regulated that they will contain suffi-
cient lime-water to purify the quantity of gas made in twenty-four hours, without having occasion to
fill them higher than the water-line shown in the engraving.
Four lime-machines are necessary, two being in action and two out, alternately. When that ma-
chine is spent through which the gas first passes, shut it off, and open a third, leaving the second to
perform the duties of the first, and 80 on.
The quantity of lime required for the complete purification of coal gas varies very much with the
quality of the lime and the gas; that coal which produces the greatest volume of sulphuretted hydro-
gen from the presence of iron pyrites will require the most lime. As the best means for arriving at a
proper practical conclusion, we annex the quantities used at different gas-works in various places.
1936.
R
At the Imperial Gas-Works, London, one bushel of quicklime purifies on an average 10,000 cubic
feet of gas, the price of lime being 7d per bushel. The lime is used both as a hydrate and in the fluid
state, in the following proportions:-For the purification of 1,000,000 cubic feet, the produce in the
winter season of twenty-four hours, eighty bushels mixed as dry lime," and twenty bushels mixed into
a fluid this quantity performs its part thoroughly.
At Cheltenham 11 bushel of quick-lime, reduced to the state of a hydrate, will purify 10,000 cubic
feet of gas perfectly cost per bushel from 5d. to 6d.
At Birmingham the purification of 1000 feet costs, in lime and labor, from 11d to 1td, but in reality
not nearly so much, as the refuse is sold for two-thirds the original cost of the lime. Lias lime is used,
and dry purifiers."
With the dry-lime purifiers at Chester, 1 cwt. 2 qrs. is required to purify 10,000 cubic feet of gas.
The Welsh lime is used, its price being 13s. 4d. per ton; therefore the purification of 10,000 feet will
cost 12d without labor, which is about the average cost.
In making the dry-lime purifiers, that they may present a sufficient surface to the gas which passes
through them, an excess, rather than a smaller area, should be given. A bushel of lime, when reduced
to the state of a hydrate, contains very nearly 4500 cubic inches: allowing that this quantity will
purify 5000 cubic feet, it follows that 12.5 square feet of screen surface is required, the depth of the
lime being 25 inches.
For retorts calculated to produce 300,000 cubic feet of gas in twenty-four hours, the purifiers should
present a surface of at least 750 square feet. If three machines are worked together, each containing
five screens, their dimensions may be 8 feet 6 by 6 feet, and 3 feet deep, four bushels of hydrate of lime
being spread on each screen. The surface presented by three machines like Fig. 1932, is 324 square
feet they were erected for an establishment producing 130,000 cubic feet of gas in twenty-four
hours.
The work performed by a lime-water purifier is generally computed by its contents in gallons, and
the head of water or pressure opposed to the passage of the gas through it. Taking the latter at a
constant quantity of eight inches, the computation is easy. 4500 cubic inches of hydrate of lime, (which
has been before stated is the quantity produced by reducing one bushel or 2150 cubic inches of quick-
lime,) mixed with forty-eight gallons of water, will purify 10,000 cubic feet of gas, if properly applied.
In the example at Fig. 1935, the lime machine contains 316 gallons, which will hold in solution thirteen
95
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bushels of hydrate of lime, and purify 65,000 cubic feet of gas. Two of these machines will therefore
do the same work as the three dry-lime purifiers before mentioned, viz. 130,000 cubic feet.
Notwithstanding, however, that the quantity of lime required may be well known, it is necessary to
test the gas in its progress through the various purifiers. A saturated solution of the acetate of lead in
distilled water is an excellent test, detecting the presence of the minutest quantity of sulphuretted
hydrogen, and more convenient than the carbonate, from its complete solubility. Test-papers may be
printed in the following form :-
Station and Date.
Crude Gas.
1st Purifier.
2d Purifier.
3d Purifier.
Lime machine having been charged - hours with - bushels of lime.
Fill a bladder, furnished with a stop-cock, full of gas from the main, before it enters the purifiers, and
also one from each separate purifier, and let the bladders be labelled; with a camel-hair pencil paint
the square marked crude gas with the test solution, and force the gas from the proper bladder upon it
while wet; the paper will immediately be turned black then paint the square marked 1st purifier, and
force the gas into it, and proceed in like manner with the two others: the paper in the fourth square
ought not to be discolored. The squares must not be moistened at once, because the first impure gas
would in that case blacken them all.
Lime for the purpose of purifying coal-gas should be free from foreign matter. That which slackens
the quickest, and produces the greatest heat during the operation, is the best. When dissolved in
diluted muriatic acid it should not effervesce, and should, when perfectly pure, leave no insoluble residue.
Gas-meter.-Before passing the purified gas to the gasometers, it is necessary that it should be meas-
ured and its quantity registered, which operations are effected by the meter. Of this machine there are
two kinds,-the station-meter, for measuring the total products of the coal at the works before it is sup-
plied to the mains; and the consumer's meter, for measuring small quantities as supplied to individuals.
Station-meter.-Fig. 1937 is a front elevation in section. Fig. 1938 is a side elevation, also in sec-
tion, of a station-meter of the capacity of 200 cubic feet, by which 300,000 cubic feet of gas may be
measured and registered in twenty-four hours.
1937.
1938.
F
A
n
Water
Line
K
G
E
D
K
H
The principal part of the machine consists of a hollow drum of thin sheet-iron A A, revolving upon
an axis a, and divided into compartments, 80 arranged, that, as the gas enters, it shall in revolving suc-
cessively fill all the chambers, pass through them, and be discharged measured.
The part of the drum which contains the gas is in the form of a concentric ring, one foot six inches
broad, and six feet deep, and seven feet six inches in extreme diameter, which will be understood by
reference to the engraving. The plates which form the sides are of the same outer diameter as the
drum, viz. seven feet six inches, but are two feet nine inches broad they will therefore project within
the smaller diameter, leaving the centre circle (through which the inlet-pipe K passes) two feet in
diameter. The surface of the water contained in the drum and outside tank of the meter, is four inches
above the upper circumference of this centre circle, when the drum is in its place; 80 that the cominu-
nication between the outside and inside of the drum is cut off by a head of water of that height, and
continues to be so in every part of the revolution. It is evident, therefore, that the gas must enter any
chamber having its inner hood above the surface of the water.
BCD E represent the inner hoods, and the direction of the gas from the inlet-pipe is shown by the
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small arrow at B. As the chamber fills with gas, it displaces the water, and causes the drum to re-
volve. Before B dips into the water, the hood C rises above the surface, and opens a communication
for the gas into its chamber; and 80 on with E, when it will have completed one revolution and
measured 200 cubic feet.
The same action that allows the free passage of the gas into the chambers causes it to be expelled
from them through the outer hoods FGHL in the direction of the arrow at F: each of these outer
hoods is sealed alternately in the same manner as the inner hoods, and opened for the passage of the
gas from them, by one constantly being above the water-line. The direction in which the drum revolves
is marked by the arrow over the top of the case.
The bevels of the division-plates dd are arranged so that they will enter the water without effort.
The axis a a on which the drum revolves is supported on friction rollers; on the front end of this axis a
spur-wheel S is fixed, working into another wheel T, having half the number of teeth; at every half
revolution of the drum it will therefore make an entire revolution its spindle passes through a stuffing-
box, and is furnished at the opposite end with another wheel V, which marks 100 feet on the index.
From a pinion on the spindle of this last wheel another wheel is worked, having ten times the number
of teeth on the pinion, which will therefore mark thousands. This last wheel is again furnished with a
pinion and works into a third wheel, which will mark tens of thousands, and so on; the quantities
marked on the dials increasing in a tenfold ratio up to hundreds of millions, or higher if thought
necessary.
The entire train of wheel-work is shown in Fig. 1939, where a is
the first spur-wheel, working upon the main axis; b the second wheel,
1939.
both being inside the meter-case c is the wheel on the opposite
end of the shaft of b, which projects through a stuffing-box on the
case, in order to communicate motion to the train of wheel-work,
which must of course be on the outside of the meter-case d is the
b
wheel driving the hand which marks hundreds on the index, and
having 100 teeth, (c has likewise the same number of teeth ;) e is the
d
pinion on the wheel d, having ten teeth; f is the wheel driving the
h
hand which marks thousands on the index, having 100 teeth, and
e
driven by the pinion e; g is the pinion of the wheel f driving h, which
marks tens of thousands on the index: and in like manner any quan-
tity may be registered. If it be required to register units, (and in
smaller meters it is useful,) the first wheel d is made to drive a pinion p. having ten teeth, to the spindle
of which the hand marking units is attached.
The consumer's meter is constructed upon precisely the same principle as that shown in Fig. 1937
but the partitions of the drum are differently arranged, and placed in such a manner, that, as they reach
the water, the surface presented shall be as small as possible. or the resistance offered shall be so
gradual that the stream of gas flowing through the machine is uniform and constant. This is necessary
in a meter from which any number of lamps are immediately supplied because the most minute
diminution or increase of the volume of gas flowing to them would cause a variation in the light, and
produce an oscillation. In a station-meter the intervention of the gasometer will remedy this defect.
A variation in the arrangement of the drum, therefore, is a matter of necessity.
1940.
As in the former case, the outer circumference or rim of the drum is divided into four partitions,
separated from each other by partition-plates, not running across directly at right angles with the face,
but bevelling from the plane of the water, meeting the wrap of the opposite hood. The sides of these
partitions are also bevelled; the space left between each plate forming, on one side of the drum, the
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inlet, and on the other side the outlet for the gas: the area of the latter being greater than the inlet, to
insure perfect freedom of action. The dotted lines show the wrap of the hoods. Fig. 1940 represents
a view of the front or inlet side of the drum, with the convex cover removed. The outlets will present the
same appearance, but of course reversed. By referring to Figs. 1941 and 1942, the remaining parts will be
1941.
1942.
62
P
a
water line
2
UNITED
10
side view inlet.
c
d
6
200
understood. The direction of the gas is marked by arrows. The box a, in which the inlet-valve is con-
tained, is soldered tight, having no communication with the rest of the case, except through the valve,
the position of which is shown by the arrows; b is the inlet-pipe projecting above the water-line, con-
veying the gas into the meter by the bent arm c, rising above the water between the convex cover and
the inlet-hoods; d is a float attached to the inlet-valve, adjusted so that when the water falls below the
centre opening, the valve will close, and the gas cease to enter the meter.
Motion is communicated to the train of wheel-work behind the index from a spiral worm w, fixed on
to the axis of the drum, working into a wheel, the spindle of which passes through the tube t, sealed by
dipping under the water contained in the case.
The following are the principal dimensions of consumer's meters:-
Number of lights
5
10
20
30
50
80
100
150
200
400
800
Diameter of drums (inches)
121
141
171
191
211
25
271
33
33
44
60
Depth of drums
"
5
6}
91
10]
11}
121
13}
201
241
301
401
Diameter of water circle
"
34
31
41
5
5
61
71
9
10
15
21
Centre opening
"
11
2
21
3
31
4
5
6
7
10
15
Hollow cover projects
"
t
1
1 g
11
1]
11
11
21
31
31
41
Depth of inner hoods
"
t
I
I
§
-
1
1
11
2
8
5
Depth of outlet
"
t
1
11
1 g
11
11
11
2
21
4
51
Capacity in cubic feet
"
25
50
100
1:50
200
3:00
400
800
10-00
20-00
50.00
Gasometers.-The simplest and most general kind, consist of an iron vessel, open at the bottom, and
inverted into a tank of water below the surface of the ground, having perfect freedom to rise and fall,
and guided by upright rods fixed at several points in the circumference. The diameters and numbers
of the vessels will vary according to the magnitude of the works to which they are attached, and the
space to be occupied by them. If the works are situated in a town, where ground is too valuable to
allow an increased extent, Telescope Gasometers" are used, which consist of three iron tanks, the one
within the other, and working like the slides of a telescope. These require counterpoises, which the
simpler form do not, and are more expensive; they work with equal precision, but are not used save in
cases of necessity.
Fig. 1943 represents the half section of a simple gasometer, capable of containing 150,000 cubic feet,
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the diameter being eighty-seven feet six inches, and height twenty-five feet. The sides A A are made
of No. 16 iron-plate, (Birmingham wire-gage,) weighing 21 pounds to the square foot, riveted together;
the top B of plate weighing about three pounds to the square foot, or No. 14 gage.
CC, etc., are rings of three-inch T iron, placed five feet asunder, and riveted strongly to the sides;
the rivets ought not to be more than three inches apart. The top and sides are secured together by
three-inch angle-iron, rolled to fit the curve.
Values
Inlet
Esit
$
1943.
stayer
dd are rings of bar-iron, about half an inch thick and three inches deep, fastened to the top by clips,
which are riveted; these rings are placed about six feet apart, and strengthened further by diagonal
bars, from one to another, breaking-joint.
E are stays formed of wrought-iron pipe, about 11 inch diameter, fixed in the situations represented,
their ends being bolted to the T iron at the sides, and the rings on the top.
G are vertical rods, fixed at their upper and lower ends to the brickwork of the tank, and being
passed through eyes fast to the bottom of the side of the gasometer, serve to guide the vessel in its
rise: their positions are between the standards S, on which are also guide-rods acting in like manner.
The eyes serve as stops to prevent the vessel rising out of the water.
The standards S, eight in number, are each formed of three cast-iron frames, six feet broad at their
bases, of the same height as the gasometer, and jointed together in the form of a T on the plan; they
are secured to the stone plinth by dovetailed lock-nuts, keyed and leaded.
H is the wooden curb, which ought always to be attached to a gasometer; its use is to regulate the
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GAS.
flow of gas from one gasometer to another. While immersed in the water of the tank it acts as a float,
and, to some extent, buoys up the vessel; when the gasometer has risen to its full height, it acts as a
weight, being partly out of the water, thus causing the gas to flow into another gasometer not yet full,
and which, having its curb completely immersed, is under less pressure.
I is the inlet-pipe, of the same diameter as that leading from the retorts, viz. eight inches. Its mouth
above the water-line should be rather bigher than the edge of the tank.
K is the outlet-pipe, twelve inches diameter, entering the gasometer, under the same circumstances
as the inlet-pipe.
L are receivers in which the tar or water collects from the mains, being pumped out by a small hand-
pump, of which a and b represent the suction pipes. P, masonry or brickwork.
A gasometer 100 feet diameter and 39 feet high at the sides, containing 300,000 cubic feet, weighs
as follows:-
Tons. Cwt. Lbs.
30 Pieces of bottom curb
6
16
30
8 Bags of rivets
0
9
94
60 Plates and rivets for bottom curb
0
1
32
24 Bottom eyes
0
8
24
100 Small sheets, 2 plates each, for side plates
2
8
17
300 Large ditto, 6 plates each, ditto
19
6
7
30 Short pieces of angle-iron bottom curb
0
3
o
24 Vertical stays
10
16
56
60 Pieces of angle-iron top curb
2
13
54
350 Short bracket irons, for crown framing
1 9 45
4 Bags of rivets
0
5
o
1 Centre crown plate
0 9 101
1 Cast-iron cup and ring
0
18
62
1 Centre pipe
0 10 28
6 Bags of rivets
0
9
86
1 Ditto 1-bolts
0 3 90
150 1-inch bolts for top curb
0
5
1
50 Upright rods
2 11 103
50 Ditto, ditto, 6 feet long
1
2
56
50 Ditto, ditto, 3 feet 6 inches long
0
9
7
150 Long braces
3 4 37
196 Crown plates
17 5 71
8 Diagonal stays, at centre pipe
0 2 64
48 Small plates, at bottom and top curb
o
4
4
1 Man-hole, cover, ring, and bolts
0 0 52
130 Small plates for joints and bolts
0 3 15
100 1-inch bolts, and 100 t ditto
0 8 64
100 f-bolts
0 0 60
50 Principal bars for roof
11 17 51
50 Secondary bars
3
16
58
50 Tie-rods for principal
4
17
86
1 Bag of bolts
0 1 17
200 Diagonal stays for roof
1 11 110
72 Cast-iron brackets for vertical stays
0 15 72
24 Timbers for middle, curb, and king-post
1 0 64
48 Tie-rods and bolts for ditto
0 12 24
12 Cast-iron carriages, rollers, and bolts, complete
2 6 56
4 Pigs of lead for ditto
0
3
0
2 Extra man-holes, plates and rings, over 18-inch pipes
0 0 100
Tons
100
6
101
24 Brackets for guide-rods
2
2
16
24 Lock-nuts for bottom of guide-rods
0
5
16
24 Guide-rods, each 6, 3, 20
9
3
8
12 Sets of tripods, each 8, 18, 3, 1
104
5
12
528 1-inch bolts for ditto
0
18
96
Tons
116
14
36
A gasometer 36 feet diameter and 12 feet deep contains 12,200 cubic feet, and weighs as follows:-
Tons. Cwt. Lbs.
Ironwork of gasometer, sides of No. 18 and top of No. 17 wire-gage
2
17
57
Wood-curb and diagonals
1
0
97
Stays and bolts
2
5
7
Sundry bolts, man-hole, etc.
0
2
28
Tons
B
5
67
8 Sets of tripods
4
19
28
3 Guide-rods
0
3
21
Tons
5
2
49
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It is hardly necessary to observe, that the cost of brick tanks will never be twice alike. If the
ground in which the tank of the gasometer represented in the engraving was built, had been less favor-
able, the thickness of the retaining wall must have been greatly increased, and other expenses incurred,
perhaps amounting to one-half more than the cost.
The " working pressure" of a gasometer will depend upon the
area of water surface, and the weight of the vessel itself. For
1944.
example, in the gasometer quoted as 100 feet diameter, the area
of water surface is 7854 feet, a stratum of which 5 150 the deep will
be equal in weight to the gasometer, viz. 100 tons 5 cwts. Its
working pressure will therefore be equal to a column of water 5
the of an inch high.
The governor.-The governor is a machine for regulating and
equalizing the flow of gas from the gasometers to the street-mains,
and is much more perfect in its action than any slide-valve applied
for that purpose requiring attendance.
Fig. 1944 is an elevation, in section, and a plan of a governor
capable of equalizing the flow of 300,000 cubic feet of gas in
twenty-four hours.
A A is a cast-iron tank containing water, five feet four inches
diameter, and four feet six inches deep, in which the regulating
vessel B B floats.
C is a cone of cast-iron, turned true in the lathe, and suspended
by an eye-bolt to the top of the floating vessel.
D is the inlet-pipe, having a plate d on the top, furnished with
an aperture, bored out to fit the diameter of the cone at the base,
and which, if raised to that height, will completely shut off the
gas from entering the vessel.
E is the outlet-pipe, its diameter being regulated by the dis-
tance to which it has to convey the gas to the equilibrium-cylinder
D
E
of the street-mains.
The floating vessel B, when immersed in water, of course loses
a portion of its weight, equal to that of the water which it dis-
places; and the density of gas contained in it will vary as the
immersion. By making the chain F of a proper weight, it may
be made to answer the purpose of a regulator of the pressure.
Let it be supposed, for example, that the vessel weighs 1000 lbs.,
and loses 100 lbs. of that weight when immersed in the water,
and that a portion of the chain, equal in length to the height
which the vessel risea, shall weigh 50 lbs., and the counterbalance
weigh 950 lbs.
lbs.
Then, when the vessel is immersed, its effective
weight is
900
To which must be added the portion of chain now
acting, as increasing the weight of the vessel
50
The sum corresponds with the actual weight of the
counterbalance
950
lbs.
Again, let the vessel be elevated out of the water, its actual and effective weight
then is
1000
To balance which is opposed the counterpoise
950
And the portion of the chain now removed to the other side of the pulley to counter-
poise, and acting with it
50
The sum corresponds with the actual weight of the vessel
1000
The effects of the vessel and counterpoise being thus opposed to each other, the pressure of the gas
contained therein is equalized.
By adding or removing the weight of the counterbalance, an increase or decrease of pressure may be
effected.
The action of the governor is as follows:-The outlet-pipe is connected with the mains, and the
inlet-pipe with the gasometer supplying gas into the machine: it will be evident, that if the density of
the gas in the inlet-pipe becomes by any means increased, a greater quantity of gas must pass between
the sides of the adjusting cone and the aperture in the plate d, the consequence of which will be that
the floating vessel will rise, and therefore contract the area of the opening in d; and if, on the contrary,
the gas in the inlet-pipe decreases in density, the vessel will descend; 80 that whatever density the gas
may at any time assume in the gasometers or mains, its pressure in the floating vessel will remain uni-
form, and consequently the velocity of the gas passing into the mains will be regular; for when the
aperture of the plate d would admit more gas than necessary for the supply to the mains, the floating
vessel rises and diminishes the area of the inlet-pipe; and when, on the contrary, the inlet does not
allow a sufficient quantity of gas to come from the gasometers, the gas passes out of the governor into
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the mains, and in 80 doing the vessel déscends, and increases the area of the inlet-pipe, to admit the
requisite gas into the mains.
This action is not influenced by any circumstances connected with pressure or velocity, but is constant
and uniform, insuring at all times a proper and sufficient discharge.
Pressure indicator.-If a governor be not used, it is advisable to have a Pressure Indicator attached
to the main or mains that leave the works, to serve as a check upon the conduct of the workmen, whose
duty it is to regulate the pressure of gas in them according to the demand at certain hours of the night.
It is thus constructed:-A small gasometer about twelve inches diameter is made to move in a tank of
water in such a manner that it shall rise or fall according to the pressure in the mains, with which it is
connected by a small pipe; a guide-rod, furnished on the top with a pencil, marks the exact amount of
pressure upon a sheet of paper coiled round a cylinder. This cylinder is moved round once in twelve
hours by a time-piece. It is evident, therefore, that if the paper be divided by
horizontal lines corresponding to the rise or fall of the gasometer by every tenth
1945.
of an inch increase or decrease of pressure; and if it be divided by vertical lines
corresponding to the revolutions of the time-piece in twelve hours, it will effect
the object required. The gasometer must be formed with an air-vessel inside,
so that when it is totally immersed it shall be in exact equilibrium with the ex-
ternal atmosphere; and when risen to its full height it shall have a pressure
equal to that required to force the gas through the mains; say the height to
which the gasometer rises is equal to ten inches, and the pressure required is
three inches; then if the paper be divided into thirty parts by horizontal lines,
each division will indicate one-tenth of an inch.
Pressure-gages, as the name implies, are instruments by which the velocity
with which the gas flows into the mains is ascertained. They are made of glass
tubes partially filled with colored water, and furnished with graduated scales
divided into inches and tenths from a point in the centre of the scale marked
zero.
When no gas is passing into the main to which one of these instruments is
attached, the columns of water contained in the tubes are in equilibrium with
B
the external air, and stand at 0. When the gas is admitted, the equilibrium is
destroyed; the gas depresses one column and raises the other, the total varia-
tion being the amount of pressure.
Fig. 1945 shows a section of a water-valve: it is formed of an air-tight cyl-
inder A A, containing a portion of tar or water. B is the inlet-pipe, which com-
municates with the gasometer; C is the outlet-pipe, which conveys the gas to
the mains; DD is an inverted cup, ten inches deep, furnished with a rod passing
through a stuffing-box, by which it is raised or lowered. When the cup is in
the situation shown in the figure, it is evident that the communication between
the outlet and inlet pipes is shut off by the pressure of a column of water ten
inches high. When the cup is raised above the mouth of the outlet-pipe by the
rack and pinion, a free passage is left for the gas.
This description of valve may be fixed with advantage between the gas-holders and the mains, or
between any system of lime-water purifiers.
Mains.-The term main is applied to all cast-iron conduit-pipes that serve to convey gas from the
works to the place or district to be lighted, and especially applied to those pipes from which smaller
ramifications branch. The diameters of the mains vary from 11 to 15 or 18 inches, according to the
quantity of gas required to be supplied, and the distance it has to flow.
The 11-inch mains are cast four feet six inches long, the two and three-inch mains about six feet long,
and all the other sizes nine feet, with a socket at one end, and a plain bead
at the other.
1946.
1947.
1948.
Sockets.-Figs. 1946, 1947, and 1948, represent the sections of sockets of
different sized pipes to a scale of 1} inch to one foot. Fig. 1948 is that
of mains from nine to fifteen and eighteen inches diameter. The usual thick-
ness of metal is shown by the hatched lines, and is proved to be sufficient.
The depth of these sockets is 4} inches.
Fig. 1947 is a section of the sockets of mains from four to eight inches
diameter ; their depth four inches.
Fig. 1946 is the thickness of those of a smaller diameter, three inches
deep.
The thickness of the main pipes ought to be as follows :-
11 inch diameter
t inch thick.
9 inches diameter
inch thick.
2 do. do.
"
"
10 do. do.
"
full.
3 do. do.
"
full.
12
do.
do.
"
"
4 do. do.
"
"
13
do.
do.
"
"
5 do. do.
"
"
14
do.
do.
"
"
6 do. do.
"
full.
15
do.
do.
"
"
8 do. do.
"
"
18
do.
do.
"
"
The annular space left between the bead end of one, and socket of the next pipe, should be about
half an inch in the large mains, and not less than three-eighths in the small.
Joints.-To make the joints, spun yarn is driven between the pipes to within 21 inches of the lip of
the socket, and a good fitting of the two pipes being effected, melted lead is poured into the remaining
cavity, which, when set, is caulked or hammered in with a blunt square-pointed chisel.
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In order to guard against the danger of water remaining that enters from the external surface into
the pipes, and the deposition of other condensed matter, a reservoir should always be placed at the
lowest point, where two or more descending mains meet and form an angle, to receive the water, etc.,
that may happen to collect at this angular point, an accumulation of which would obstruct the passage
of the gas through the mains. These receivers ought to be at least twice the diameter of the mains
between which they are interposed, and four times that diameter in depth. These receivers afford the
best indication of the sound or leaky state of the system of mains. In all instances where the pipes
are perfectly sound, observation has shown that half a mile of gas-mains, three inches in diameter, does
not deposit more than a quart of condensed vapor or water in the year; on the other hand, when the
mains are leaky, the water of the reservoir requires to be pumped out, particularly in wet weather, as
frequently as once a fortnight. The loss of gas by such leakage is much greater than is generally
imagined. In order to keep the common air out of the faulty mains, a constant influx of gas is often
necessary this is of course so much gas lost to the economy of the establishment.
Distribution of gas through mains.-The velocities of different gases under the same pressure will
be to one another, inversely, as the square roots of their specific gravities; therefore a heavy gas will
be discharged through the same opening with a less velocity than, that due to a lighter gas. For ex-
ample, if coal gas of the specific gravity 420, and with a pressure of five-tenths of an inch, flows through
a circular orifice one-fourth of an inch in diameter, at the rate of eighty cubic feet per hour, gas having
the specific gravity 400 will flow through the same opening at the rate of 819 per hour, pressure ro-
maining the same. For by inverse proportion,
As 400 = 20-000
Is to 80, the quantity discharged of the heavy gas,
So is 420 = 20-493
To 819, the quantity of lighter gas discharged.
The discharges of the same gas through different open-
ings and under the same pressure, are proportional to
the areas of the orifices in circular inches, or to the
Diameter
Quantities of gas discharged in cuble
squares of their diameters. Allowing an excess in the
of orifice in
feet per hour. Pressure = 5-10ths.
inches and
larger openings for the difference of the friction, the
parts.
By experiment.
By calculation.
results of the annexed experiments will agree very
nearly with this law.
25
80
To obtain the velocities of the same gas from any
50
321
320
other opening, say,
75
723
720
As the square of given opening,
1:00
1287
1280
Is to the given quantity discharged,
1.125
1625
1620
So is the required opening
1.25
2010
2000
To the required quantity discharged.
150
2885
2880
The quantities of the same gas discharged in equal
600
46150
46080
times by a horizontal pipe under the same pressure and
for different lengths, are to one another in the inverse
ratio of the square roots of the lengths. Hence, when we know the quantity of gas discharged from a
given length of pipe, we may find the quantity discharged by any other length with any pressure, and
of gas of any specific gravity.
Example of the foregoing rule.-It is required to find the number of cubic feet that will be discharged
from a horizontal pipe six inches diameter and 1760 yards long, the specific gravity of the gas being
-420, and the pressure, equal to five-tenths of an inch perpendicular head of water. We know by
experiment that 44,280 cubic feet will be discharged by a six-inch pipe 3.46 yards long; therefore, by
inverse proportion, say,
As 1760 = 41-952, the required length,
Is to 44,280, the known quantity discharged,
So is 3:46 = 1·860, the known length,
To 1963-2, the required quantity discharged.
We therefore find that the loss by friction in a pipe a mile long is 44,116'8, the initial velocity being
equal to 46,080 by calculation.
A horizontal main, 16 inches diameter and 1760 yards long, is laid from the works to the equilibrium
cylinder: it is required to know how many cubic feet of gas of the specific gravity 390 will be dis-
charged with a pressure equal to a head of water of 6-10ths of an inch.
We have found by the last example that a six-inch pipe, one mile long, with a pressure of 5-10ths of
an inch, will deliver 1963 cubic feet of gas having the specific gravity 420, in one hour. Then say, as
36, the square of the diameter of the six-inch pipe, is to 1963, the quantity of gas delivered, 80 is 256,
the square of the diameter of the sixteen-inch pipe, to 13,959, the required quantity delivered by a
sixteen-inch, one mile long. For the difference of specific gravity, say,
As 390 = 197, the specific gravity of the lighter gas, is to 13,959, the quantity delivered of the
specific gravity 420, 80 is 420 = 204, the specific gravity of the heavy gas, to 14,455 = the quantity
delivered of the specific gravity 390.
And for the difference of pressure, say,
As .50 = 707, the first pressure, is to 14,455, the quantity discharged through a sixteen-inch pipe
by that pressure, so is ·Bo = 774, the required pressure, to 15,824, the required quantity, of specific
gravity 390 discharged from a sixteen-inch pipe, with a pressure equal to 6-10ths of an inch head of
water. The actual quantity discharged is about 16,500 cubic feet.
96
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An accurate experiment was made by Mr. Clegg, at the Pancras Station, on the quantity of gas dis-
charged through a four-inch main, six miles in length, with a pressure of three inches perpendicular
head of water. The specific gravity of the gas was not taken until some hours after the experiment,
when it was found to be 398.
A new four-inch main had to be laid for the purpose of supplying parts of the parish of St. Maryle-
bone with gas; after completing a circle of nearly six miles in circumference, it terminated within the
distance of a short street from the point at which it left the works. By completing this distance, the
two ends of the pipe were brought together on exactly the same level. There were no short bends,
and all the services and branches were closed. The pipe measured exactly six miles in length. The
leakage was ascertained in the first place by shutting the valve adapted to the returned end, and ob-
serving the gasometer; it was found to be thirty-three cubic feet at the end of one hour, and was
allowed for. At the commencement of another hour the valve was opened and free passage given to
the gas, which was allowed to escape: by observing the gasometer at the end of this hour, it was found
that 885 cubic feet had been expended; deducting thirty-three cubic feet from this for the leakage,
852 will remain for the actual quantity discharged at the end of six miles. This experiment is valua-
ble to the practical man, both for the unquestionable data it supplies, and for its close approximation
to the rules here laid down.
The quantity discharged by calculation is
873 cubic feet
By experiment
852
"
Difference
21
TABLES of the different quantities of coal gas of the specific gravity 420, delivered in one hour, from
horizontal pipes of different diameters and lengths, and under different pressures.
QUANTITIES DELIVERED BY A TWO-INCH MAIN IN CUBIC FEET.
Length of
Pressure in inches and parts.
Perpendicular head of water.
pipe in
yards.
0.50
0.75
100
1.50
2-00
300
10
2896
3558
4185
4923
5792
6950
15
2364
2904
3331
4089
4728
5768
20
2047
2507
2886
3541
4094
4994
25
1830
2241
2580
3165
3660
4465
30
1673
2049
2368
2894
3346
4082
40
1445
1770
2037
2490
2890
3525
50
1294
1585
1824
2238
2588
3157
100
915
1121
1290
1582
1830
2232
150
748
916
1054
1304
1496
1825
200
647
792
912
1119
1294
1578
250
579
709
816
1010
1158
1412
800
522
639
736
903
1044
1273
400
457
559
644
790
914
1115
500
409
500
576
707
818
997
QUANTITIES DELIVERED BY A SIX-INCH MAIN IN CUBIC FEET.
Pressure in inches and parts.
Perpendicular head of water.
Length of
pipe in yards.
0.50
0.75
1-00
150
200
3-00
100
8242
10095
11657
14276
16484
20190
150
6730
8242
9517
11657
13460
16484
200
5828
7138
8242
10095
11657
14276
300
4759
5828
6730
8242
9517
11657
440
3929
4813
5557
6806
7858
9626
500
3686
4515
5213
6384
7372
9030
600
3365
4121
4759
5828
6730
8242
700
3115
3816
4406
5396
6230
7632
880
2778
3403
3929
4813
5557
6807
900
2747
3365
3886
4759
5494
6730
1000
2606
3192
3686
4515
5213
6384
1760
1965
2406
2778
3403
3929
4813
2640
1604
1965
2269
2778
3208
3929
3520
1389
1702
1965
2406
2778
3403
5280
1134
1389
1604
1965
2269
2778
7040
982
1149
1389
1702
1965
2298
8800
879
1076
1287
1521
1758
2152
10000
824
1010
1166
1428
1648
2019
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GAS.
763
QUANTITIES DELIVERED BY A TWELVE-INCH MAIN IN CUBIC FEET.
Pressure in inches and parts.
Perpendicular head of water.
Length of
pipe in yards.
0.50
0.75
100
1.50
200
3.00
100
32968
40380
46628
57104
65936
80760
150
26920
32968
38068
46628
53840
65936
200
23312
28552
32968
40380
46628
57104
300
19036
23312
26920
32968
38068
46628
440
15716
19252
22228
27224
31432
38504
500
14744
18060
20848
25536
29488
36120
600
18460
16484
19036
23312
26920
32968
700
12460
15264
17624
21584
24920
30528
880
11112
13612
15716
19252
22228
27224
900
10908
13460
15544
19036
21816
26920
1000
10424
12768
14744
18060
20848
25536
1760
7860
9624
11112
13612
15716
19252
2640
6416
7860
9076
11112
12832
15716
3520
5556
6808
7860
9624
11112
13612
5280
4536
5556
6416
7860
9076
11112
7040
3928
4596
5556
6808
7860
9624
8800
3516
4304
5148
6084
7032
8608
10000
3297
4038
4663
5710
6594
8076
In the foregoing Tables we have considered the mains as horizontal.
In mains rising above the horizontal line the quantity of gas delivered by them will be greater, and
in mains falling below that line it will be less. In the first instance, the resistance offered to the flow
of gas by the atmospheric pressure will be lessened, and in the latter it will be increased, and will
cause a difference in the necessary pressure for the discharge of the gas of one-tenth of an inch head of
water for every ten feet rise or fall.
The effect of bends and angles in the main, upon the quantity of gas delivered, is essentially a matter
of experiment: they may be considered as 80 many mechanical obstructions. The results of the fol-
lowing experiments will show, in some measure, what allowance to make for quadrant, semicircular,
and right-angle bends. A two-inch pipe thirty feet long, perfectly horizontal and free from obstruc-
tions, delivered 2898 cubic feet of gas in one hour, with a pressure of five-tenths of an inch head of
water. The same pipe, disconnected in the middle of its length, and returned by a semicircular bend
to the point at which it left the gasometer, delivered 2754 cubic feet in the same time, being a differ-
ence of nearly one-twentieth in the whole quantity. The semicircular bend was removed and a quad-
rant bend substituted, making the two fifteen-foot lengths of pipe form a right angle with one another;
the quantity delivered was 2834 cubic feet in the hour, a difference of about 1-45th of the first dis-
charge. Again, the pipes were disconnected, and a right-angle bend substituted for the quadrant; the
quantity delivered in the hour was 2824, a difference of 1-39th of the first discharge.
Services are wrought-iron or pewter tubes, for the purpose of supplying the interior of houses with
gas from the mains; every small tube on to which a burner is fixed, whether for public or private use,
is called a service. The arrangement of these tubes, and their adaptation to the interior of private
dwellings, shops, &c., is a separate branch of business, and fitters" are almost universally employed,
who work independently of the gas companies.
In order that the pipes for conveying the gas from the mains and distributing it through the houses
or other buildings to be lighted, may in the first place be neither unnecessarily large or too small, the
following rule is given:
One gas-lamp consuming four cubic feet in an hour, if situated forty feet from the main, requires a
service not less than a quarter of an inch in the bore.
2 lamps,
40 feet from the main, require a three-eighth service.
8
"
30
44
"
a three-eighth tube.
4
"
40
"
"
a half-inch service.
6
"
50
"
=
a five-eighth service.
10
"
100
"
a
a three-quarter service.
15
"
130
"
"
an inch service.
20
"
150
"
"
a service 11 in diameter.
25
"
180
"
"
a 11 service.
30
"
200
"
"
a service 11 in diameter.
It is desirable that all bends should be circular. No branch ought to proceed from a service of a
quarter of an inch in the bore, and no more than two from a three-eighth service. All pipes, before
they are fixed, must be proved by condensing air into them by means of a hand-syringe while under
water; the leak will be easily detected by the air-bubbles which rise through the water. For con-
ducting the gas from the street-mains into the interior of a house, or any building to be lighted, a
wrought-iron pipe of sufficient diameter is tapped into the main, and carried in a straight line to the
nearest wall of that building, through which it must pass; and on the inside be furnished with a good
stop-cock. If all the fittings rise from the main no siphon is necessary, but if any part of them fall
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GAS.
below the main a small receiver must be attached to the lowest point, fitted with a screw-plug at the
bottom, 80 that any moisture may be drawn off. The pipes which convey the gas to the burners must
be in as direct a line as possible, to avoid unnecessary expense and obstructions. The union joints
used to connect two services together must be of the same diameter as the pipes, and soldered firmly
on to them.
The excessive cost and defective construction of fittings have in numerous instances tended more
than any thing besides to engender prejudices against gas, and more particularly in private houses.
Gas-fittings ought to be made of the best materials; they should be judiciously arranged, and fixed
by skilful workmen. The choice of a situation for the main cock is of importance; it should be placed
as near as possible to the inside of the wall through which the gas is admitted from the street-main,
and where it will at all times be accessible to the inmates of the house. The key or spanner by which
it is turned should always be attached, and the nick which indicates whether it is open or shut should
be distinctly marked. The cock should be literally a stop-cock.
Throughout their various ramifications the pipes should have a slight inclination towards the point
where the main cock is fixed, and thence to the street-main; this is to allow the water, which is occa-
sionally deposited in them, to drain off without interrupting the passage of the gas. In fittings which
are not thus arranged the water accumulates in some curvature of the pipes, and occasions an oscilla-
tion, or, as it is very commonly called, jumping of the lights.
The intensity of light is ascertained by an instrument called the Photometer, invented by Count
Rumford; it is constructed on the principle that the power of a burning body to illuminate any defined
space is directly as the intensity of the light, and inversely as the square of the distance. If two un-
equal lights shine on the same surface at equal obliquities, and an opake body be interposed between
each of them and the illuminated surface, the two shadows must differ in intensity and blackness, for
the shadows formed by intercepting the greater light will be illuminated by the lesser light only and
inversely, the other shadow will be illuminated by the greater light-that is, the stronger light will be
attended with the deeper shadow but it is easy, by removing the stronger light to a greater distance,
to render the shadow which it produces not deeper than that of the smaller, or of precisely the same
intensity; this equalization being effected, the quantity of light emitted by each lamp or candle will be
as the square of the distance of the burning body from the illuminated surface. By reference to the
diagram, Fig. 1949, the instrument will be rendered perfectly intelligible.
A is a wooden box, painted black inside, except at the back
D
B, which is painted white, (or a sheet of fine white paper
©
fastened to it may be preferable;) C is the substance inter-
cepting the light of the gas-lamp D, and throwing a shadow on
the paper. C is formed of a strip of thin brass, about a quarter
of an inch broad, movable round its axis on a pin at the top and
bottom, so that its shadow may be adjusted to correspond in
breadth to that cast by the lamp; for the candle being nearer,
1949.
if its intercepting wire were of the same diameter as that of the
lamp, the shadow would of course be much broader, and tend
to deceive the operator. D is the lamp placed 5 feet from the
wire C;. E is the candle-socket sliding upon a rod, which is
marked according to the number of candles the gas-lamp is
equal to.
If, when the candle is placed at 1, the two shadows are
equal, the lamp only gives a light equal to one candle; if at 2, the lamp is equal to 4 candles; and if
at 4, the lamp is equal to 16 candles.
A simple rule-of-three statement will give the comparative quantities of light, the candle being at
any distance. The burner remaining 5 feet from the interposed wire, supposing the candle to be
1 5-10ths of a foot from its wire,
The square of 1.5 = 2-25.
The square of 5·0 = 2500.
Then as 2.25, the square of the candle's distance, is to 10,
80 is 25'00, the square of the lamp's distance, to 11·11, the number of candles
the gas-lamp is equal to.
Gas-exhauster.-Much attention has been directed to discover an effectual method of relieving the
retorts from the pressure occasioned by the necessary obstructions with which the gas has to contend
in the purifying process, and in its subsequent passage to the gas-holder.
The pressure required to surmount these resistances, varies in different establishments according to
the method of purification employed, in some cases being equal to a column of water of 36 inches.
The annexed engraving represents a gas-exhauster designed by Mr. Methven for the Commercial Gas
Company's Works, Stepney.
This machine consists of three vertical wrought-iron cylinders, which are made to rise and fall in a
tank containing water, by the revolution of a treble crank-shaft with connecting rods and guides.
Each of these cylinders is inverted over a chamber of cast-iron, the interior of which communicates
with the hydraulic main. The top of each chamber is provided with a flap-valve, which allows the gas
to escape into the movable cylinders, during the ascent of the latter by the action of the crank. The
cylinders have valves on the top, similar to those in the cast-iron chambers, which during the descending
stroke allow of the discharge of the gas into the upper part of the external cistern. From the cistern a
main leads through the purifiers to the gas-holder, and the gas is thus pumped out of the retorts and
discharged into the gas-holder, independent of any amount of pressure required to be overcome in its
passage.
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The velocity of this machine is regulated by the use of conical strap riggers to suit as nearly as
possible the amount of gas being generated, but in order to avoid the possibility of the pressure upon
the hydraulic main becoming less than that of the surrounding atmosphere, and the gas thereby
becoming impoverished by the admixture of atmospheric air, a regulating machine is attached to the
exhauster, which, by self-action, maintains that pressure perfectly uniform. The regulator consists of a
chamber which communicates alike with the inlet and outlet passages of the exhauster, and which is
divided by a valve or conical plug acted upon by a float sustained in water, under the immediate
influence of the exhausting power of the machine. The action of the float is communicated to the
valve with the smallest amount of friction by a lever and connecting rod with the usual adaptation of
a water joint, and the effect is, that when the machine from any cause is reducing the pressure of gas
upon the hydraulic main below that of the atmosphere, and thereby causing a partial vacuum in the
retorts, the float of the regulator is by the same means depressed, and the communication between the
inlet and outlet of the exhauster, thereby opened to a sufficient extent to restore the equilibrium.
1950.
The most perfect equilibrium is maintained between the interior of the hydraulic main and the
atmosphere, during the various velocities. The pressure has been even increased to 48 inches of
water without any sensible variations in the effect upon the gage indicating the pressure upon the
hydraulic main. The highest speed of this machine is calculated to discharge 60,000 cubic feet of gas
per hour, at a pressure of 30 inches, and will not then require a driving power greater than that of
three horses.
Dry gas-meters.-The ordinary wet gas-meter described, is unexceptionable where fraudulent means
are not employed for under-estimating the amount of gas consumed, but its construction admits of great
deception being practised by dishonest consumers. If, for instance, the water level in the meter be
lowered, more gas will pass through than is registered by the instrument; if the case of the meter be
tilted forward to an angle of from 5° to 13°, according to its construction, and a proportion of the water
drawn off, so as to expose the outlet of the measuring chamber, the gas will pass through it without
affecting the index, and without being registered at all. This is constantly done, and the large amount
of gas which is unaccounted for in the calculations kept at the gas-works, and which is frequently at-
tributed to leakage, is no doubt traceable to this nefarious practice. In cold weather the water in the
meter is liable to freeze, and the passage of the gas is then completely stopped. The use of a solution
of caustic potash or soda has been proposed, which is not so easily affected by frost, to replace the
water in the meter, which will also tend to render the gas more pure, should either carbonic acid or
sulphuretted hydrogen have escaped the general purifiers. The objections to the use of the wet meter
stated above, have given rise to great ingenuity in the construction of a variety of measuring instru-
ments, in which the use of water or any liquid is dispensed with, and in which the gas is measured by
the number of times that a certain bulk will fill a chamber capable of undergoing contraction and ex-
pansion by the passage of the gas. These alternate contractions and expansions of the chamber set
certain valves and simply constructed arms in motion, which, by the aid of a few wheels, can be made
to turn the hand of a dial, as in the ordinary wet meter. We will restrict our remarks upon dry
meters to one of the most recent inventions, which appear well calculated for affording accurate meas-
urements.
Messrs. Croll and Richards' meter consists of a cylinder or case A A, Fig. 1951, divided by a plate B
in the centre into two separate cylindrical compartments, which are closed at the opposite ends by
metal disks C C. These metal disks serve the purpose of pistons, and are kept in their places by a
kind of universal joint attached to each; the space through which the disks move by the action of the
gas, which affords the means of measurement in this meter. is governed by metal arms and rods, shown
in the side cut, Fig. 1952, which space, when once adjusted, cannot vary. To avoid the friction attend-
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GAS.
ing a piston working in a cylinder, a band of leather DD is attached, which acts as a hinge, and folds
with the motion of the disk; this band is not instrumental in measuring the gas, 80 that its contraction
or expansion would only decrease or increase the capacity of the hinge, the disk being still at liberty
to move through the required space only. The leather is also attached in such a manner that it can
only bend in one direction, and this renders it much more durable.
1951.
1952
D
D
B
C
C
D
D
The machine is comparable to a steam-engine measuring its steam, which it does in all cases by the
strokes of the piston. The gas enters the cylinder at the top, from the space occupied by the arms,
valves, &c., Fig. 1953, and forces the disks bodily forward through a certain space the motion commu-
nicated by the disks to the arms and rods causes the supply of gas to be cut off, and admits of its
escape by another valve; at the same moment the gas is admitted to the other side of the disk, and
this is forced to return to its original position, traversing, of course, the same space as before. Each
backward and forward motion consequently indicates the passage of a constant quantity of gas, and
the same apparatus which admits and shuts off the supply by means of valves is connected with clock-
work, and thus the motion of the disk, or the quantity of gas which has passed through the meter can
be indicated upon a dial-plate, as in the ordinary wet meter.
Gas-burners-From the leaden pipes-in the circuit of which the meter is placed, if used at all-
the gas enters brass tubes, which project from the wall, and passes to the burners, each of which must
be furnished with a separate brass stop-cock. Good tight stop-cocks are much more difficult to make
for so light a gas, than for liquids. Instead of fixing the carefully ground conical plug into its place by
a screw, which occasions either too much friction or an imperfect joint, it is better to use a watch-
spring, which, in spite of the wear, keeps the plug always tight. The gas-burners are quite similar to
lamp-burners; by the former we are to understand the different mouth-pieces attached to the ends of
the tubes for burning the gas. As neither the wick nor the level of the oil has here to be considered,
the management of these burners is comparatively simple; but as the amount of fat in candles and
lamps required regulation, 80 here the amount of gas consumed in a given time must bear a proper
relation to the current of air from without, i. e. the flame must neither smoke, nor must it be too short
and blue. Such regulation is partly effected by the cock attached to the burner, and all excess of gas
is avoided from the beginning by allowing the gas to issue only from very small apertures. In passing
through such apertures, the original velocity of the current of gas is much increased, and the flame thus
acquires the proper size and height.
A great variety of gas-burners have been successively brought into public notice, all of which lay
claim to the production of an increased intensity of light with a smaller consumption of gas. It is im-
possible, however, from a mere inspection of the flame produced by these burners, without accurately
measuring the amount of gas consumed by each, to arrive at any conclusion as to which form is the
most economical or generally desirable. Until impartial comparative experiments have been instituted
with all, decided preference cannot be ascribed to any one in particular.
Fig. 1954 is a representation of Whinfield's lucent burner, in which the Liverpool button is applied
to an Argand gas-burner, and the peculiar form of chimney causes an external current of air to
impinge at a certain angle upon the flame, producing the same effect as the metallic cone in the solar
lamp. A basket of wire-gauze is fitted into the crutch of the burner, which moderates the supply
of air from below, and prevents the flickering caused by sudden draughts, by fixing the chimney
to a circular ring, which screws up or down upon the triangular support. Lowe, in his improvement
upon this form of burner, alters the direction of the external current caused by the contraction of the
chimney, and by converting the button into a screw, its height can also be altered and the internal
current regulated.
Fig. 1955 shows a form of burner patented by Mr. Leslie, in which the gas is caused to flow through
a number of small copper tubes, instead of from the apertures of an Argand burner. The object of this
is to effect a more complete combustion of the gas by surrounding each single jet with abundance of
air, as it issues from the orifice; and the low form of chimney or combustion chamber diminishes the
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767
velocity of the draught, and adds, consequently, to the illuminating power of the flame. The orifices
of the copper tubes become stopped up, either with sulphuret of copper or the ammoniacal oxide, and
require to be cleansed with a stiff brush. The only effectual remedy for this objection to the burner, is
the use of purer gas.
1953.
1954.
Ventilation of gas-burners.-Serious objections still stand in the way of the introduction of gas-light
into private dwellings, unless some means can be adopted for removing the products of combustion.
For every cubical foot of gas burnt, rather more than a cubic foot of carbonic acid is produced. A pound
of coal gas contains, on an average, 03 of hydrogen, and 07 of carbon; it produces, when burnt, 2.7 of
water, and 2.56 of carbonic acid gas; consumes 4'26 cubic feet of oxygen, which is the quantity con-
tained in 193 cubic feet of air. It is thus obvious that the air of a close chamber must soon be vitiated
by the combustion of gas, and that the consequences of breathing an atmosphere impregnated with a
large proportion of carbonic acid must consequently soon be felt by the inhabitanta. The water evolved
at the same time, in the state of steam, is found to be seldom free from sulphurous and sulphuric acids,
derived from impurities in the gas: and this, condensing upon the furniture, books, goods in shops, dec.
very soon damages them in a very perceptible manner. The large quantity of water evolved from the
Bude burner in lighthouses, condensing on the glass windows and materially impeding the passage of
the light, attracted the attention of Mr. Faraday to the invention of some means for effectually removing
the noxious products of combustion. After several more or less successful trials, the method illustrated
by Fig. 1956 has been adopted, and exhibits a beautiful adaption of the principle of a descending draught
to a lamp-burner: a is an ordinary Argand burner, with a common straight chimney ee; the glass-
holder c is, however, 80 constructed as to sustain not merely the chimney, but an outer cylinder of glass
also ff. larger and taller than the inner one ee; the glass-holder has an aperture d. connected by a
mouth-piece with a metal tube i, which serves as a ventilating flue, and which, after passing horizontally
to the centre of the chandelier, ascends to produce draught, and carry off the products of combustion
into the chimney or the open air; d is the pipe connected with the burner for supplying gas. The outer
cylinder f is closed at the top by a plate of mica g; or still better, by two plates of mica, one resting on
the top of the glass, and the other h dropping a short way into it. They are connected together by a
metal screw and nut, which also keeps them a little apart from each other. The chimney and burner
may then be surrounded by a ground-glass globe, which has no opening except at the bottom for the
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768
GATES, WROUGHT-IRON.
admission of air to the burner. The course of the current of air, carrying with it the products of com-
bustion, is indicated by the direction of the arrows.
It is stated that the intense heat produced by the hot current of air traversing the space between the
two glass cylinders, causes the glass to become more or less opaque, and thus obstructs the passage of
the light. To avoid this objection, the same principle has been applied in a still more elegant and
perfect manner to a ventilating gas-burner, a section of which is represented in Fig. 1957 b is the
1955.
d
0
1956.
C
1957.
f
i
b
K
a
a
c
d
b
burner, with an ordinary chimney, discharging the products of combustion into the metal tube F; K is
a large glass tube, open at the top, in the vicinity of the metal flue F, from which it is suspended.
The air for feeding the flame descends in the direction of the arrows, enters the burner at b, and is
carried off through the flue F C, after having supplied oxygen to the flame and become vitiated.
Ventilating burners of this kind not only prevent the diffusion of the products of combustion through
the apartments in which they are erected, but with the hot current of gas ascending through the
metal tube a large quantity of air from the room is also carried away, and thus a proper circulation
established.
GATES, wrought-iron, for the United States Dry Dock at Brooklyn, New York.
The danger of accident by fire and decay, and the increasing difficulty of procuring timber, especially
of large dimensions or peculiar shapes, has directed the attention of engineers to the substitution of iron
for wood in structures designed for permanence. European engineers have been long forced to make
this substitution, by the increasing cost of timber.
The ingenuity and skill of artisans have led to some very beautiful designs and applications of iron,
producing great strength with small weight and dimensions. The substitution of iron for wood has been
heretofore chiefly confined to the construction of vessels and bridges. Sufficient experience has demon-
strated the great superiority of iron over wooden vessels, and as soon as the prejudices of the old
constructors are overcome it will doubtless be used exclusively.
In America timber can be obtained at a moderate cost, unless it be of unusual dimensions or shapes,
and a general substitution of iron will be more distant. The difficulty of procuring the immense tim-
bers required for the construction of the folding gates of the graving dock at New York, led to an
examination of the question of substituting iron for wood.
There have been no works of this kind constructed in America; and even in England and France
most of the recently built docks have been provided with gates of wood. A few iron gates of large size
have been constructed; among them are those for the new graving and wet docks at Woolwich, Sheer-
ness, Shinburness, Bristol, Dundee, and Montrose, and for the locks on the Caledonian and Elsmere
canals at an earlier date. and also for the docks at Sevastapol on the Black Sea.
The mode of constructing these gates has not been published, except in the case of the docks at
Montrose, and the gates of the locks of the Caledonian canal. The general plan which has been
adopted has been to construct a frame of cast-iron, and cover it with a sheathing of wooden planks;
some of those recently constructed are covered with a sheathing of boiler-plate.
The low temperature of the atmosphere in this climate renders the use of cast-iron dangerous where
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GATES, WROUGHT-IRON.
769
it is subject to violent concussions; and to avoid this difficulty Mr. McAlpine (the engineer who designed
these gates) proposed the adoption of wrought instead of cast iron for the frames of the gates.
The successful introduction of these plates of wrought-iron in the construction of the tubular bridges
over the Menai Straits, has given a direction to the use of this kind of iron which will produce important
changes in the designs of such structures.
A beautiful application of the same description of iron has been made in the design for the gates of
the graving dock at New York.
It is believed that no experiments have hitherto been made, at least none have been published, on
the strength of iron thus applied. Some of the best practical engineers in the United States have ex-
pressed doubts as to the strength of the horizontal ribs of the gates as arranged on the annexed plan.
To satisfy these doubts, a trial-bar was modelled after the form proposed, and full size, and subjected
to pressure. The result of this experiment has proved that the strength of a bar thus formed has been
under instead of over rated.
The following tables of the deflection of the bar under various weights possess great interest.
The bar was set up, supported at its extremities, and loaded by weight suspended from the centre;
provision was made against the lateral extension of the bar by placing it between solid abutments of
masonry, which happened to be convenient for the purpose; care was also taken to preserve it in a
truly vertical position. The whole arrangement is shown in the annexed sketch.
$16
1960.
1959.
1958.
1961.
Fig. 1958, elevation of the apparatus used in testing the strength of the wrought-iron bar intended for
the folding gates of the United States Dry Dock, Brooklyn Navy Yard
Fig. 1959, plan of the same.
Fig. 1960, cross section of the frames for preserving the bar upright Fig. 1961, scale.
Levels taken at each loading on different parts of the bar, as well as the weights applied at each
loading, are given in the tables. The weights are given in pounds, and the deflections in decimals
of a foot.
97
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770
GATES, WROUGHT-IRON.
The bar was thirty-seven feet long, twenty-two inches wide, and three-fourths of an inch thick, and
made of three plates, for the length, secured by splicing plates riveted.
The point marked No. 5 in the table was in the centre of the bar, and the other points equally dis-
tant from each other.
TABLE No. 1.
TRIALS.
No. 1.
No. 2.
No. 3.
No. 4.
No. 5.
No. 6.
9,798 lbs.
16,821 lbs.
24,697 lbs.
32,883 lbs.
39,710 lbs.
55,132 lbs.
No. of mark
on boards.
Total
Total
Total
Total
Total
Total
Deflec-
Deflec-
Defiec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Defiec-
Deflec-
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
0
000
000
005
-005
009
004
005
001
008
.009
012
003
1
-000
000
003
003
005
002
004
002
003
.001
001
000
2
-002
002
005
007
002
005
'010
.015
004
-011
-011
022
3
001
001
004
005
007
012
005
017
007
024
007
031
4
003
003
009
012
008
020
004
024
010
034
014
048
5
025
025
007
032
008
040
006
046
022
068
005
073
6
001
001
010
009
008
017
003
020
010
030
010
040
7
.004
004
008
012
004
016
008
024
'001
025
016
*041
8
-002
002
.005
003
005
008
002
010
-001
009
002
-011
9
.001
'001
003
002
001
003
000
003
000
003
-002
005
10
*000
000
003
003
003
006
008
002
008
-006
003
003
The bar was then left, loaded with 55,132 pounds, for 201 hours, at which time the loading was
resumed.
TRIALS.
No. of mark
on bar.
No. 7.
No. 8.
No. 9.
No. 10.
No. 11.
No. 12.
55,132 lbs.
61,786 lbs.
67,788 lbs.
76,143 lbs.
84,620 lbs.
92,609 lbs.
0
.006
003
000
003
000
003
002
.005
002
003
000
003
1
000
001
.002
003
001
004
002
002
002
.004
000
004
2
.005
007
.004
025
005
026
003
029
003
032
019
051
3
001
030
005
035
.005
.040
012
.042
-011
053
044
097
4
001
049
011
060
012
072
007
079
010
089
080
-169
5
.003
070
008
178
*011
089
007
076
012
-108
057
-165
6
000
040
005
045
005
050
005
055
013
068
051
-119
7
.008
033
008
041
004
045
008
053
008
-061
039
·100
8
-002
013
001
014
002
016
001
015
004
-019
019
039
9
004
.001
-001
000
003
003
-001
004
000
.004
004
008
10
001
004
002
'002
.001
003
001
004
001
003
000
003
Table showing the amount of elongation in the bar during the first experiments.
Weight
No. of
Different points on the bar.
on the
bar in
Experi-
Observations.
pounds.
ments.
a.
1
2
3
4
5
6
7
8
C.
in.
in.
in.
in.
in.
in.
in.
in.
in.
in.
a and C were
0
0
0
0
0
0
O.
O.
0.
0
0
9,798
1
points immedi-
32,883
4
005
005
ately over the
39,710
5
005
003
001
001
.003
005
plumb face of
55,132
6
010
.008
005
.003
.005
007
.005
010
altar No. 9 ;-
more reliance
61,786
8
.010
008
005
003
005
007
008
010
69,788
9
.015
010
may be placed
on their accura-
76,143
10
016
-010
84,620
11
.016
.013
cy than on that
of the others.
92,609
12
NOTE.-In consequence of an imperfection in the arrangement which was made for securing the beam in a vertical
position, at the twelfth loading, it lurched to one side, and prevented a continuance of the experiment.
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GATES, WROUGHT-IRON.
771
The bar was repaired, and the following experiments were made without abutments, which allowed
the ends to move horizontally ; it was loaded as stated in the first set of experiments.
TABLE No. 2.
No. 5.
No. 1.
No. 2.
No. 3.
No. 4.
33,673 lbs.
No. 6.
Between 4 and 5
11,771 lbs.
20,354 lbs.
31,495 lbs.
33,673 lbs.
an interval of 15
No. of mark
35,961 lbs.
on bar.
hours.
Total
Total
Total
Total
Total
Total
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Defiec-
Defiec-
Deflec-
Deflec-
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
.
0
001
001
.001
002
001
.003
1
-002
-002
001
.003
001
004
2
013
013
.014
027
018
045
8
026
026
021
047
030
077
4
035
-035
028
063
038
·101
5
035
.035
035
070
046
-116
-010
-126
.005
181
007
138
6
031
031
031
062
045
.107
7
029
-029
023
052
032
084
8
.016
016
-012
028
.020
048
9
.005
-005
008
013
003
016
10
000
000
000
000
001
.001
No. 7.
No. 8.
No. 9.
No. 10.
No. 11.
No. 12.
38,033 lbs.
40,131 lbs.
41,973 lbs.
44,456 lbs.
46,074 lbs.
48,179 lbs.
No. of mark
on bar.
Total
Total
Total
Total
Total
Total
Defiec-
Deflec-
Defiec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Defiec-
Deflec-
Deflec-
Defieo-
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
0
.005
006
1
-010
010
2
.074
085
3
.130
-154
4
175
.203
5
014
-152
.008
·160
.017
.177
.023
.200
008
208
020
228
6
183
209
7
.143
·166
8
085
098
9
028
033
10
004
000
004
000
004
The bar was then left, loaded with 48,179 lbs., for 20 hours, at which time the loading was resumed.
No. 15.
No. 16.
No. 18.
No. 13.
No. 14.
56,694 lbs.
56,694 lbs.
No. 17.
58,894 lbs.
Between 15 and
Between 15 and
Between 17 and
48,179 lbs.
52,209 lbs.
16 an interval of
16 an interval of
58,894 lbs.
18 an interval of
No. of mark
bar. go
20 minutes.
20 minutes.
20 minutes.
Total
Total
Total
Total
Total
Total
Deflec-
Deflec-
Deflec-
Defiec-
Deflec-
Defiec-
Deflec-
Deflec-
Defiec-
Deflec-
Deflec-
Defico-
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
0
002
008
001
-009
001
010
000
010
000
-010
000
010
1
003
013
000
013
000
013
000
.013
000
013
000
018
2
008
093
002
095
-016
'111
010
-121
007
128
006
134
8
-013
167
004
.171
036
207
-018
.225
016
.241
-012
253
4
015
-218
.008
.226
043
269
026
295
019
314
-015
329
5
018
246
-015
261
047
308
026
334
025
359
-015
379
6
017
226
004
230
050
-280
027
307
020
327
020
.341
7
013
179
004
183
036
219
-020
239
016
.255
-014
267
8
008
-106
.003
.109
029
.129
014
.143
.009
152
.009
-161
9
003
036
-002
038
009
047
000
047
004
051
.001
052
10
000
004
000
004
000
004
-001
.005
000
.005
000
005
Digitized by
Google
772
GATES, WROUGHT-IRON.
1966.
1964.
1963}.
SC
1962.
2'2'
1963.
1965.
1967.
Digitized by Google
GATES, FLOATING.
773
No. 23.
No. 24.
No. 19.
No. 20.
No. 21.
No. 22.
65,284 lbs.
65,284 lbs.
Between 22 and
Between 23 and
60,904 lbs.
No. of mark
63,104 lbs.
65,284 lbs.
65,284 lbs.
23 an interval of
24 an interval of
on bar.
2 hours 50 min.
17 hours.
Total
Total
Total
Total
Total
Total
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
Defiec-
Deflec-
Deflec-
Deflec-
Deflec-
Deflec-
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
tion.
0
*000
010»
000
010
000
010
001
-011
000
012
*001
015
1
000
-013
000
-013
000
-013
-001
014
000
014
003
017
2
008
-142
023
.165
015
-180
011
191
.004
-195
005
200
8
.014
267
048
315
013
328
038
366
.007
373
006
379
4
022
351
064
415
022
437
049
486
007
493
010
503
5
026
405
076
481
034
-515
054
569
012
581
010
591
6
022
363
077
440
028
468
039
507
013
520
007
527
7
016
283
059
342
028
370
024
394
007
.401
008
409
8
-010
.171
029
200
019
219
012
231
005
-236
005
241
9
-003
055
-013
068
008
.071
003
074
001
-075
006
081
10
000
-005
000
005
000
005
000
005
000
-005
000
005
These experiments having demonstrated
that the bars as arranged were of sufficient
strength, the construction of the gates was
No. 25.
No. 26.
No. 27
commenced.
Fig. 1962 shows an elevation of the back
67,314 lbs.
side of the gate.
No. of mark
71,804 lbs.
75,299 lbs.
Figa. 1963 and 19631 are vertical and hori-
on bar.
Total
Total
Total
zontal sections of the mitre post.
Deflec-
deflec-
defiec-
Deflec-
tion.
Figs. 1964 and 1965 are the same sections of
tion.
tion.
tion.
the quoin post.
Fig. 1966 is a plan of the horizontal rib, and
0
002
015
010
a horizontal section of the gates.
1
002
019
Fig. 1967 is an elevation of the front of the
2
-005
205
423
gate.
3
007
386
844
In the article " Dry Dock," at page 401, a
ft. in.
full description and specifications of these
4
007
512
820
1.152
gates are given, to which the reader is re-
5
004
595
1.450
ferred.
6
-003
530
860
1272
There being nothing peculiar in the cap-
7
001
410
953
stans and sluice-gates and other fixtures,
8
008
249
514
they have been omitted in the drawings.
9
003
084
-169
GATES, CANAL See Locks OF CANALS.
10
000
005
*000
GATES, FLOATING. Specifications for
constructing the wrought-iron floating gate, or
The levels of experiment No. 57 were taken after the
caisson, for the United States Dry Dock, at the
bar broke.
Brooklyn Navy Yard, represented in plan, sec-
tion, and elevation in Figa. 1968, 1969, 1970.*
Dimensions.-The vessel is to be 50 feet long on the keel and 69 feet on the deck. The width in the
centre is to be 4 feet on the bottom, and curved to 16 feet at 6 feet above the bottom, and to continue
this width to the top.
The width at the end is to be two feet.
The whole height is to be 31 feet.
The sides are to be curved on a radius of 88 feet 7 inches at the top, and diminished 80 as to pre-
serve the width at the stems (2 feet) and in the centre (16 feet) for the upper section of 24 feet.
The ends or stems are to be built to conform to the shape of the masonry of the dock. The bottom
or keel is to be 50 feet long, straight; the stem is to be curved on a radius of 3 feet 10 inches for 21
feet in height, and then on a curve of 56} feet radius for 19] feet in height, and then carried up on a
bevel to the top, 9 feet in height, making the whole height (including the keel) 31 feet.
Ribs.-There are to be 26 ribs on each side of the gate. The 14 centre ribs are to be 24 inches
apart, 4 to be 25, 4 to be 26, and 4 to be 27 inches apart; each set of ribs are to be formed of 4 plates
exclusive of the bulwarks. The two bottom plates from the opposite side are to lap past each other
8 feet over the keel, the lips being turned opposite ways to allow them to be riveted together where
they lap.
The two bottom plates are to be each 20 feet long, and are to be formed of angle iron, 5 inches on
each angle and I inches thick, with rivets # inches diameter, and 4 inches apart, or rectangular plates
of iron 6 by 1 inches, secured by angle iron.
The two side plates are to be each 20 feet long, and to lap past the bottom plates 9 feet, and to be
riveted to them; the rivets are to be 1 inch diameter, and 6 inches apart. They are to be formed of
angle iron, 4 inches on each angle and 1 inch thick.
A general description of the caisson or floating gate is given in the article " Dry Dock," p. 402.
Digitized
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Google
774
GATES, FLOATING.
"A
1969.
B
N°
HC
1968.
Plan.
DD
00
1970.
+
a
+
Digitized by Google
GATES, GUARD.
775
The bulwarks are to be formed of plates 7 feet long, and to lap on and be riveted to the side plates;
they are to be formed of angle iron 21 by 3 inches, and i inch thick.
Sheathing.-The bottom plates are to be bent to form the sides of the keel they are to be 6 feet
long, 2 feet wide, and I inch thick. The vertical joints are to be butted; the plates are to be riveted
to the angle iron running lengthwise of the keel, with 1 inch rivets 21 inches apart; they are also to be
riveted to the angle iron of the ribs in the same manner.
The horizontal joints are to be butted on a line, and the plates to be riveted to a piece of iron on the
inside, between the ribs, 4 by 5 inches; the rivets to be as before described.
The rivets on the bottom and sides of the keel and stem, and the bottom of the vessel, are to be
countersunk.
The sheathing plates, to a vertical height of 6 feet 10 inches, will be made of the same sized plates,
and secured and riveted in the same manner.
The next two courses above are to be made of t inch plates; the next four courses above of 1 inch
plates; the next three courses of t inch, and the bulwarks of 3-16th inch plates, all secured and riveted
in the manner above described.
The rivets through the & and t inch plates will be 1 inches diameter, and 21 inches apart through
the 1 and t inch plates they will be 9-16th inches diameter, and 21 inches apart; through the 3-16th
inch plates they will be i inches diameter. The lapping plates on the inside of the horizontal joints
will be made of the same thickness as the sheathing plates. The bulwarks will be braced with light
wrought-iron knees, and sealed up on the inside with light sheet-iron.
The keel and stems.-The keel and stems are to be formed of a single plate of iron for the keel, and
each stem forged and welded together. The plates are to be 2 feet wide, and I inch thick.
The sides of the keel are to be made by bending the bottom sheathing plates, and of the stems, by
bending the side sheathing.
The bottom plates and the sheathing are to be connected by angle iron, 4 inches on each flange, and
1 inch thick, to which both plates are to be riveted. The rivets are to be 1 inch diameter, 21 inches
apart.
The stiffening plates in the keel will be 3 feet long on the top, 15 inches deep, and 1 inch thick;
plates of cast-iron, transversely and longitudinally, are also put in.
The part which projects into the keel will be cut to the interior shape, cutting out the bottom corners
for the angle iron, and the shoulders to fit against the bottom sheathing plates.
The stitfening plates will be placed between the plates of each rib, and will be riveted or bolted
through both plates, where they lap past each other.
The nine courses of horizontal stiffening plates in the stems are made of cast-iron, conforming to the
curve of the sides of the vessel on the outside edge, and fitted to the shape of the interior of the stem.
They are to be placed at each horizontal joint of the sheathing, and take the place of the butting strips.
Plates of angle iron 3 inches wide on each flange, and 1 inch thick, will be riveted to the sheathing
plates, and bolted to the stiffening plates.
Deck.-The angle iron is to be 4 by 2 inches, 1 an inch thick. The covering is to be formed of sheets
about 6 feet long, 2 feet wide, 3-16th inch thick, made of scratched iron. Rivets to be 1 inch diameter,
and 2 inches apart.
The combing of the hatches will be made of cast-iron, bolted to the angle iron.
Suituble ring-bolts will be put in the deck, and on each quarter outside of the vessel.
Tube braces will all be 14 inches diameter, and made of & inch wrought, or 1 inch cast iron; the flanges
of the tubes are to be 21 inches wide on each end, and bolted to the sheathing.
The cast-iron chambers will be cast in halves, and planed and fitted together, and riveted through the
chamber and flanges of the tube, and secured with tap bolts on the top.
The valves will be of cast-iron, planed and fitted; the seats will also be planed and fitted closely.
There will be four branch pipes discharging into the interior of the vessel, by means of similar valves.
The valves will be raised by a stem of 1f inch round iron, guided by a frame, and operated by a
hand-wheel and screw on the level of the deck.
There will be a steam-engine with a cylinder of 6 inches diameter and 18 inches stroke, and a suit-
able locomotive boiler set under the deck, and two double acting force-pumps 15 inches diameter, (the
pumps are also to be arranged to be worked by hand.) The whole is to be made portable.
A flight of iron steps is to be put in at the stem at each end, and extend from the deck to the bottom
of the vessel.
The keel will be suspended from and braced to the sides of the vessel, to meet the different strains to
which it will be subjected when floating, and when aground in peace. This bracing is made by a
trussing of hollow cast-iron pipes, 5 inches diameter, through which are passed suspension rods of
wrought-iron, 21 inches diameter.
General remarks.-All of the joints exposed to the water shall be chipped, and calked so as to be
water-tight.
All of the iron and other materials used shall be of the best quality, and shall be bent and forged to
the required shape, to conform to the plans, and shall be neatly and accurately fitted.
The riveting shall be done when hot, and the rivets made to fill the hole completely.
The whole surface, both outside and inside, shall be painted with two coats of red lead and oil, and a
third coat of such other color as may be directed.
GATES, GUARD. One of the most complete examples to be found is at Lowell, Massachusetts, at
the head of the Northern Canal, the principal feeding canal to the large manufacturing establishments of
that city. It was constructed by James B. Francis, Esq., Agent of the Locks and Canals Company. The
average width of the canal is 100 feet, the depth of the water 15 feet; the sides being nearly perpen-
dicular. The guard gates are placed at its entrance from the Merrimack river, for the purpose of regu-
lating the quantity of water to be admitted, and for protecting the canal and a considerable part of the
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GATES, GUARD.
city from freshets, which sometimes raise the level of the water in the river 10 to 13 feet above its
ordinary height. The entrance to the canal being nearly in the direct line of the stream, it was necessary
that the guard gates and masonry should be of great solidity, to withstand the violent action of the
ice in the spring freshets; as the river sometimes breaks up suddenly when the ice is from eighteen
inches to two feet thick, and not sensibly weakened by previous warm weather.
Figs. 1971 and 1972. The water is admitted to the canal through ten openings, each eight feet wide
and fifteen feet deep in the clear. These openings are separated by piers of hammered granite A A,
two feet thick, fifteen feet high, and a little over fifty feet long. These piers rest on a granite paving
BBB, laid on the rock CC of hard mica slate. The openings are covered with granite lintels D DD,
about two feet thick, resting on the piers; wells E E being left for the gates F. Above the lintels the
masonry is carried up under the gate-house to the height of twelve feet, and below the gate-house, six
feet higher, for the passage of the road G leading to the Pawtucket bridge across the river.
1971.
1972.
M
T
S
S
P
o
G
H W.
E
D
H
E
a
L. W.
A
A
The gates F are made of white-oak timber, one foot thick, laid one above the other, and connected
together with four bolts, two inches in diameter, passing through the feet of the castings H, to which
the screws I are attached, and passing down through the middle of the gate to a cast-iron plate K,
forming the bottom of the gate. The ends of the gate project into grooves at each end, and are faced
with plates of cast-iron 7 inches wide and 11 inch thick. These plates slide on the castings L built into
the masonry; the sliding surfaces being planed so that they make a joint nearly water-tight. The
gates are raised and lowered by means of two screws II, about 17 feet long and 5 inches diameter,
with threads of one inch pitch. These screws pass through the hubs of the pair of geers M M, which
are cut into female screws. The pair of geers are driven by one pinion N placed at the bottom of the
upright shaft 0, on the top of which is a bevel geer P, driven by another pinion Q placed on a hori-
zontal shaft driven by pulleys R and leather bands or belts SS, three inches wide. There are two sets
of pulleys and belts to each gate, one to raise the gate, the other to lower it. The proportions of the
geering are such that the belt travels 1800 times faster than the gate. The belts are all driven
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GEER-CUTTING MACHINE, BEVEL.
777
by the shaft T carrying the pulleys U. This shaft is driven
by a water-wheel of fifty-horse power, by which means
the whole of the gates can be lifted at one time, under
almost any circumstances, in fifteen minutes.
1973.
GEER-CUTTING MACHINE, BEVEL. For the cut-
ting of bevel geer an admirable machine has been recently
invented and patented by George H. Corliss, of Provi-
dence, R. I., in whose shop (Corliss, Nightingale & Co.) it
is in successful operation. From the specifications of the
patentee we extract the following full and clear descrip-
tion of the machine, its distinguishing characteristic, con-
struction, and operation.
Fig. 1973, plan of the machine.
Fig. 1974, a side elevation.
Figs. 1975 and 1976, enlarged cross sections, taken at
the line A a of Fig. 1973; the former with certain parts
removed.
Fig. 1977, another cross section at the line Bb of Fig.
1974.
Fig. 1978, a vertical cross section at the line C c of Fig.
1976.
Figs. 1979 and 1980, enlarged end and side views of the
cutter and carriage.
Fig. 1981, an enlarged separate view of the hinge which
0
0
E
forms the axis of the guide-bar on which the cutter carriage
x
1
slides.
Fig. 1982, an enlarged separate view of the end of the
guide-bar, with a stem connected therewith.
0
0
The same letters indicate like parts in all the figures.
In the machines heretofore employed for cutting cogs
of toothed wheels, a rotating burr cutter has been used;
and although this is, to a certain extent, effective for cut-
ting spin geer, yet in cutting the cogs of bevel geer it is,
h.
from the very nature of the case, defective. The cogs,
when cut with a rotating cutter, must be defective for the
following reasons: if the sides of the cutter-wheel be
parallel, the space cut out between the cogs will also be
parallel, whilst in bevel-wheels they should be in the lines
of the radii, that is, farther apart at the outer than at the
inner periphery; and if to avoid this the sides of the cut-
0
]
ter-wheel are bevelled, to make the spaces wider by cut-
0
0
ting deeper towards the outer periphery, then the spaces
will be wedge-formed in their section, which is at variance
with the proper formation of cogs, for the spaces below
0
0
the pitch-line should be vertical, or curved inwards, and
from the pitch-line upwards curved outwards; and these
0
0
curves should be sections of cones, which cannot be formed
u
by a rotating cutter, which, from
the very nature of its operation,
0
0
will make the same curve from
0
0
end to end of the cog.
The object of this invention is to
avoid this objection; and for this
purpose the first part of the inven-
tion consists in the use of a recip-
72
rocating cutter, governed by a
guide-bar on which the cutter
carriage slides, and which has its
axes of vibration to adapt the cut-
ter to the required depth of cogs
at the apex of a cone correspond-
a
ing with the bevel of the wheel
to be cut, whether such axes be
fixed or adjustable to wheels of
different sizes, that all the cuts
may be in the direction of the
radii.
The second part of the invention
consists in combining the guide-bar,
on which the cutter carriage runs,
with a secondary frame hinged to
the main frame outside of the circle
of the largest wheel intended to
98
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778
GEER-CUTTING MACHINE, BEVEL.
be cut in the machine, that the axis of vibration of the guide-bar may be elevated or depressed to
adapt the machine to different bevels; and that the main driving shaft, which communicates motion to
the operative parts of the machinery placed at the hinged end of the said frame, may be in the line of
the axis of vibration of the said frame, that the vibration thereof may not change the relative position
of the driving shaft and the parts receiving motion therefrom.
The third part of the invention consists in combining with the guide-bar a guide-plate, against which
it bears by means of a weight, spring, or the equivalent thereof, 80 that as the guide-bar descends to
give the proper depth to the cogs, the said guide-bar shall follow the curve of the guide, and thus de-
termine the form of the face of the cogs.
And the last part of the invention consists in making that part of the rear end of the guide-bar which
rests against the guide, movable, 80 as to have an endwise motion, in or on the said bar, in the direction
of its length; the said movable part or stem being bevelled back of where it rests against the guide,
and so connected, either with the guide-bar or some other part of the machinery, that at the time of the
cutting motion it will move forward. that its bevelled surface may be brought in contact with the guide
and give a lateral motion to the guide-bar, to relieve the cutter from the surface of the cog that is being
cut, to admit of its moving back clear of the cog; and then, at the end of the return motion, a reversed
motion to bring the cutter in the proper line for cutting.
1983.
q
1974.
a
In the accompanying figures, a represents the main frame of the machine, to the inside of which is
adapted a frame b that carries the spindle c of an index-plate, made in the usual manner. This frame
b is secured to the main frame by the bolts dd that pass through elongated holes ee in the side pieces
of the main frame; and as there are several of these holes along the frame, the index-plate can be
moved to any place required on the main frame, to adapt the machine to wheels of various sizes. The
upper end of the spindle c is adapted, like other cutting engines, to receive the wheel f to be cut. A
secondary inclined frame h is provided near one end with a shaft i, the journals of which run in boxes
jj at the end of the main frame, so that the secondary frame can be inclined to any desired extent with
the axis of the index-wheel to determine the bevel of the cogs to be cut. And the extreme rear end of
the secondary frame is provided with a bolt and temper-screw that pass through a segment mortice
in the main frame, by means of which the secondary frame may be secured and held in place at any
inclination required. The shaft i of the secondary frame extends out sufficiently on one side to receive
one loose pulley k, and two fast pulleys 1m, one on each side of the loose pulley. The loose pulley k
turns freely between and on the barrel of the other two in я manner well known to machinista. And
the inner end of the fast pulleys Im is provided with a pinion n, which engages and carries a cog-wheel
o that turns on a stud-pin p, and the arbor of the wheel carries a pinion (see dotted line in Fig 1974)
that engages and carries a sector-rack q on the end of a rock-shaft r, provided with a pendulous arm s,
to the lower end of which is joined a connecting rod t that takes hold of the rear end of a carriage &,
(as seen in Fig. 1980,) to which is secured the cutter v, in any appropriate manner. The carriage alides
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GEER-CUTTING MACHINE, BEVEL.
779
on a guide-bar w properly formed for this purpose, as shown in the figures, and in turn this guide-bar
alides inways x, connected by a socket y with a stud 2 that projects from an arbor a' which turns on
pivot screws b' b', that pass through the two cars c' c' of a plate d', secured by bolts or screws to the side
pieces of the secondary frame, 80 that by shifting these screws the plate can be moved along the sec-
ondary frame, as the index-plate and its spindle can be moved along the main frame to adapt the
machine to the cutting of wheels of various diameters. The guide-bar is thus connected with the sec-
ondary frame by a universal joint, and the connection of the universal joint with the secondary frame
can be shifted to adapt the machine to the cutting of wheels of different sizes, and as the axis of the
vertical vibration of the guide-bar must always be in the line of the axis of the index-plate. the mode of
shifting either the one or the other must be such as will admit of accurate adjustment. For this purpose
the holes in the main frame, through which the securing bolts pass, are elongated. The machine is
driven by two belts e'f', one being crossed, and the two governed by a double belt-shipper g', 80 formed
that when the direct belt e' runs on the pulley m, to give the cutting motion to the cutter carriage by
the connection of parts from the pinion 71, the crossed belt f' runs on the loose pulley k, and when the
belts are shifted at the end of the cutting motion, to reverse the motion, the crossed belt runs on and
1976.
1977.
h
B
x
h
1979.
1975.
h
u
V
b
carries the pulley 1, and with it the cutter carriage by the same connections, and the direct belt e' then
runs on the loose pulley; or, if desired, this arrangement of belt may be reversed. In this way the
desired motions are given, and the shifting of the belts is effected in the following manner: The belt-
shipper is attached to the outer end of two rods i'i' that slide in a plate h' attached to the frame, and
these way-rods i'i' are connected by a cross-bar is with one arm of a right-angle lever j', the other arm
of which passes to the inside of the main frame, and is there jointed to a rod k' which passes through a
thimble i, jointed to the pendulous arm 8 that communicates motion to the carriage. The rod k' is pro-
vided with two adjustable stops m'm', on each side of the thimble, and at such distance apart that
when the pendulous arm 8 moves forward to effect the cutting motion, towards the end of this motion
the thimble strikes one of the stops m', and shifts the belts to give the return motion, towards the end
of which the other stop m' is struck to re-shift the belts. In this way, by simply varying the distance
between the two stops m', any desired range of motion can be given to the cutter carriage, to adapt it
to the length of the cogs to be cut.
As before described, by reason of the universal joint connection, the guide-bar is free to move either
vertically or horizontally, and with it the cutter carriage which slides on it. Its rear end is suspended to
a cord o' which passes over a pulley p' with a counter weight q' attached to it, by which it is held up
against the end of a set screw r', the turning of which will therefore determine the depth of cut to be
made by the cutter. This guide-bar is also borne laterally by means of a bent lever s', (see also Fig.
1977,) one arm of which acts against it, and the other attached to a cord t' that passes over a pulley u',
and is provided with a weight v'. This weight always tends to bear the guide-bar in one direction,
horizontally, and against a guide-plate w', one edge of which is formed 80 as to determine the form to be
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780
GEER-CUTTING MACHINE, BEVEL.
given to the face of the cog, and as this plate can be removed, others may be substituted to suit the
various and desired forms of cogs. The rear end of the guide-bar, however, does not bear against this
guide-plate, but, instead of this, there is a stem x' with a socket in its forward end that slides accu-
rately, but freely, on a projection y', Fig. 1982, from the rear end of the guide-bar, 80 that one can slide
on the other longitudinally; and this stem it is that bears against the guide-plate. The rear end of the
stem is looped to receive the arm z' of a slide a². It will be observed that whilst the stem is in the
position represented in the drawings, as the rear end of the guide-bar is moved up and down to cut the
depth of the cog, the stem x' follows the curvature of the guide w', and therefore communicates a cor-
responding motion to the point of the cutter in a direction converging to the centre of the universal
joint, on which the guide-bar w vibrates, and that, therefore, any curve to be given to the cross section
of the cog will be gradually reduced as it approaches the axis of the wheel. But when the cutter is to be
moved back, it is necessary that it should run clear of the metal, and for this purpose the stem x', back
of the part which is represented as bearing against the guide-plate, is curved inwards, or bevelled as
at b², so that when this part is brought in contact with the guide-plate a slight lateral motion is given
to the guide-bar sufficient to relieve the cutter. The required endwise motion for this purpose is given
to the stem by the operation of shifting the belts to reverse the motion of the cutter. The inner arm
of the lever j', of the belt, carries a box c3, that slides freely on the slide a³, and towards the end of the
forward motion of the cutter carriage; this box strikes against a stop dᵃ, from which the arm z', con-
nected with the stem x', projects and forces forward the stem to the distance required to bring the
bevel ba against the guide-plate w' to relieve the cutter. The cutter carriage then runs back and
towards the end of this back motion; the box on the lever of the belt-shipper strikes another stop e3,
on the slide a², and moves back the stem to bring the cutter in the proper line for making its cut. In
this way at each operation the cutter is relieved and returned to its proper position for cutting. The
cutter is fitted in any desired manner in a socket in the carriage, and when it is desired to cut cogs of
the form represented in the enlarged Fig. 1983, the cutting edge of the cutter must be bent forward, as
shown in that figure.
1982.
w
1980.
o
0
0
и
1978.
on
1981.
x
y
b
O
0
c'
h
In a machine constructed and operating on the principle of this invention, every cut converges to the
apex of a cone that represents the bevel of the wheel, and therefore the cogs, and the spaces between
them, will gradually and in the true proportion diminish from the outer to the inner periphery. Thus far
as to the mode of operation of the machine for cutting the faces of the cogs on one side but as each cog
has two faces on opposite sides, 80 soon as one face of all the cogs have been cut, the machine must be
reversed to cut the other side, and for this purpose it is simply required to reverse the cutter V, the
guide-plate 20', and the lever 8. The reversed position of these parts is shown in dotted lines in Figs.
1977 and 1979. By the shifting of these parts, it will be observed that the machine will cut the re-
versed side of the cogs. The lower end of the cutter should be properly formed to give the required
shape to the bottom of the cogs.
The patentee claims, first, The method of cutting the cogs of bevelled wheels by means of a recipro-
cating cutter that moves in or on a slide, or slides, that vibrates on an axis that coincides, or nearly so,
with the apex of a cone representing the bevel of the whecl to be cut, substantially as herein described,
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GEER-CUTTING ENGINE.
781
by which vibration the depth of the cut is determined, and irrespective of the adjustment of the axes
of vibration as described.
Secondly, The guide-bar, (or its equivalent,) on which the cutter carriage runs, and having its axis of
vibration for the depth of cut, as above described, when combined with a secondary frame jointed to the
main frame at some point outside of the circumference of the wheel to be cut, that the machinery may
be adapted to the cutting of cogs on various bevels.
Thirdly, In combination with the guide-bar, having a universal joint, or the equivalent thereof, and
operated substantially as described in combination with the guide-plate, to guide the cutter and deter-
mine the form of the face of the cogs, as described.
And lastly, Making that part of the guide-bar which rests against the guide-plate to determine the
form of the face of the cogs separate from, and movable on, the guide-bar, and properly bevelled to
relieve and clear the cutter for its back movement, substantially as described.
GEER-CUTTING ENGINE. Figs. 1984 and 1985 are front and side elevations of a geer-cutting
engine, as built by the Lowell Machine Shop, sufficiently large to cut a geer 7 feet in diameter and 8
a
m
F
0
N
c
X
E
If
1985.
a
A
inches face. This is a heavy and strong-built machine, adapted to cutting spiral spur and bevel geers,
without any additional fixtures.
M is the spindle to which the geers are fastened when being cut, and to which is attached the dial-
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782
GEER-CUTTING ENGINE.
plate B, on the upper surface of which are drilled circular rows of holes very accurately spaced off ; by
means of this, and the spring and point N, Fig. 1984, the geer is divided into the required number of
teeth.
A, hand-wheel for raising and lowering spindle M when cutting small geers. For cutting large spur
or bevel geers, the geer remains stationary, and the head to which the cutter is attached is traversed
up and down by means of the crank D, which moves the pinion d, geering into a larger geer H, on chain
pinion-shaft. An endless chain running up over a pulley K is attached to the plate, to which the cutter
shaft stand is attached. This stand can be turned around at any angle for spiral or worm geers.
1984.
o
K
G
e
H
0
D
E
M
R
B
6
Z
R, guide for spindle when cutting worm, or slightly spiralled geers. When spiral geers of greater
angle are to be cut, there is a circular inclined plane of plate steel screwed to the cylindrical part of the
yoke, (under the dial,) which bears on a friction roll attached to the main frame. It is kept against this
roll by means of the weight G, at the end of the string passing over the grooved pulley F.
P, weight to balance spindle M and the geer, being cut. This weight has a pinion playing into the
rack on the top of the long arm of the lever o, by means of which it can be moved forth and back to
balance geers of different weight.
G', crank and pinion geering into segment, for setting the head at an angle for cutting bevel geers.
C, driving pulley coupled to cutter shaft.
L, geer on nut for rai-ing the cutting head. It is worked by a pinion L' on the end of the upright
shaft, to which a hand-wheel is attached.
E, crank and bevel geers which communicate with the screw inside of frame, by means of the geers
E'. Turning this crank moves the head stock to different positions, for different sized geers.
bb, arms to which the cord and weight are attached when cutting spiral geers.
This machine is a very convenient one to work at, as the operator can stand in one position and com-
mand overy part of it.
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GEER-CUTTING ENGINE.
783
Figs. 1986, 1987, another form of geer-cutting engine for cutting bevel, spiral, and spur geers, also
made by the Lowell Machine Shop.
Fig. 1986, side elevation.
Fig. 1987, front or end elevation.
EE are the end standards which form part of the frame.
D, swing slide, in which the cutter head slides when cutting bevel geers.
B, hand-wheel on pinion shaft passing through the axis of the swing slide D, which has a pinion
geering into a rack on the back side of the cutter head, for traversing the cutter.
E
X
o
4
R
A
1986.
L
I
R
C, handle nuts for fastening the swing slide in the circular slot at any angle required.
A, driving pulley on the shaft that drives the cutter shaft. This pulley and shaft are fixed. The
cutter shaft can be taken out without throwing off the belt, as the two shafts are connected together
with a clutch coupling.
N, hand-yheel on screw for traversing cutter head to suit geers of different diameters, or in cutting
worm geers, &c.; to the left of N are seen the screw and lever for fastening the head.
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784
GEERING.
G, dial or index, having rows of holes of different numbers drilled on its face, which can be divided
by means of the point and spring I, 80 as to cut any number of teeth wanted.
K is a hand lever for raising spindle F and dial with the geer while cutting. This lever is on one
end of a short shaft passing through a stand, and on the other end there is a quadrant, to which a chain
is attached, that connects with the long lever L, on which the spindle stands.
1987.
A
B
D
c
C
E
H
K
G
P
L" is a balance lever weight to counterbalance the spindle and dial, and the weight of the geer
which is being cut. The weight has a movable cover for the purpose of putting in more or less weight,
as the heft of the geer being cut may require.
To the extreme left of the upper part of the frame, Fig. 1986, is a thumb-nut for tightening up the
spindle in case it should wear and become loose.
H, pulley over which the cord passes to support the weight P, used in cutting spiral geers.
GEERING is the general term employed to denote a combination of mechanical organs, interposed
between the prime mover and the working parts of machinery. Frequently, however, the signification
is restricted to the series of toothed wheels by which the motion is conducted from one revolving axis
to another, independently of the shafts and bearings by which they are supported. Two toothed wheels
are also said to geer when they have their teeth engaged together, and to be out of geer when separate
and consequently out of action.
In the transfer of motion from one axis to another in a system of mechanism, wheels are the most
important organs. Of these there are two principal varieties with several modifications, distinguished
by peculiarities of form, construction, and adaptation.
When motion is to be transferred from one axis to another which is parallel to it, the peripheries of
the wheels act upon each other tangentially, and the teeth are disposed round their cylindrical surfaces
in the direction of radii from their centres. Wheels of this sort take the general name of spur geer. In
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GEERING.
785
the ordinary cast-iron wheels, the teeth are made in one piece, with the rim, and commonly the wheel
consists of one entire piece, though sometimes the wheel is cast in segments when of very large size,
and especially if intended for shipment, for convenience of packing and transport. Cast-iron wheels of all
sizes above, and frequently below 18 inches diameter, are made with arms; but in
very small-sized wheels the arms are commonly omitted, and the rim and teeth are
1988.
united to the central boss by a thin continuous plate, as represented in elevation and
section, by the annexed cuts. Wheels of this sort are usually denominated plate-
wheels, to distinguish them from those of similar size having arms, and which are
therefore described, especially by clock-makers, as being crossed out. In very
small machinery the wheels are sometimes formed out of plain disks by cutting
out a series of equidistant notches round the circumference.
In wooden wheels, which were in general use for all species of millwork till towards the end of the last
century, and of which we have still some examples, the teeth are formed of separate pieces, and fixed
into equidistant mortises pierced through the rim of the wheel. The rim is formed of segments of hard
wood firmly bound together by iron straps and bolts, and is connected to the shaft by a wooden framing,
consisting of bars set at right angles. The square opening, thus left at the centre to receive the shaft,
also of wood, and square at that part, is purposely made larger than the section of the shaft, to admit
of adjustment and fixing by wedges. The arms are, however, very frequently mortised into the shaft:
but such a mode of fixing weakens the shaft, and at the same time renders it difficult to get the wheel
off, should this be required in consequence of the failure of the shaft.
Wheels of this kind are technically known as cog-wheels, and the teeth take the name of cogs. These
are made of some well-seasoned hard wood, as mountain-beech, plane-tree, hornbeam, hickory, and the
like, with the grain disposed in the direction of their length, which being the radical direction, is the
most favorable to transverse strength.
A modification of this construction of toothed wheels is still very commonly employed in millwork
under the name of mortise-wheels. In these, the body of the wheel is of cast-iron, and the teeth of
wood, fixed into mortises made in the rim, as in the old cog-wheel. The individual teeth, or cogs, are
often formed so that the part which projects without the rim is the tooth; and the shank, tail, or tenon,
is made to fit its mortise in the rim of the wheel very tightly, and is left sufficiently long to project on
the inside, so that being driven into the mortise up to the shoulders, it is secured in its place by an
iron pin inserted into a hole bored through the tenon, closely under the rim of the wheel.
There is, however, another mode of fixing the cogs, which is more commonly practised than that
described. This mode will be understood by reference to Fig. 1990, from which it will be observed
that the cogs, instead of being made fast in their places by pins, are retained in the mortises of the rim
by dovetail keys v v, driven between every contiguous pair inside of the rim. The tenons. when the
cogs are intended to be fitted in this manner, are made with an expanding dovetail at their extremities,
to receive one side of the key, which being driven tightly into the V-shaped space, thus formed between
the ends of each pair inside of the rim of the wheel, retains the cogs in their places. The keys, which
are made of well-seasoned hard wood, usually.of the same kind as that used for the cogs, are made
long enough to project some way beyond the side of the rim, to
1991.
allow of their being driven in more tightly, should the cogs in the
course of working become loose. The ends of the tenons are
b
1,
c
S
8
c
also very commonly made flush with the surface of the keys, but
b
b
the mode of finishing shown in Fig. 1991 has some advantage in
point of strength.
Spur mortise-roheel.-Fige. 1989 and 1990 give two views in
elevation, and Fig. 1991 a section of a mortise spur-wheel of 841
1989.
inches diameter, and containing 48 coge; pitch 21 inches.
Fig. 1991 is a section of the wheel where a a represents the
cogs; r r the ring; c c the face arms; bb the feathers of the arms,
and SS the socket or eye of the wheel
Fig. 1989 is a view parallel to the axis of the wheel, and Fig.
1990 is a plan of the same wheel in the line of its centre.
These figures are intended to illustrate the mode of drawing
the wheel. The pitch and number of cogs being given, the first
part of this operation is to determine the diameter of the pitch
circle. This may be done by multiplying the pitch of the teeth
1990.
by their number, and dividing the product by 3.1416; or it may
be directly found from the rule and table given in page 795; or
the compasses may be at once set to draw the pitch circle from
scale of Fig. 2022, (see pages 799 and 800.) The pitch being
21 inches, the radius of the pitch circle will be found in the line
which runs parallel with A D, and which is marked 24; and the
distance C to 48 in that line being the radius for a 21 inch pitch
with 48 teeth, one point of the compasses placed in the intersec-
tion of the line 21 by C B, and the other in the intersection of the
line terminating in 48, will be that radius. The other required
dimensions will also be found in the line 21; the distance A C = the pitch; a c = the length; b = the
:hickness; a c = the length from the pitch line to the point, and twice this is the working depth; the
width of space is A b, and their lateral clearance is A b C b, and the bottom clearance a C 2 c.
The same scale may be used in finding the proportions of parts in making out reduced drawings of
wheels to different scales. If the compasses be set to the required pitch, and moved up the line C B,
keeping one point in CB until the other point meets the line A B, the points running parallel to A C,
99
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786
GEERING.
then in a line drawn parallel to A D, and passing through the points in which the compasses meet the
converging lines, will be found all the other required dimensions in accordance with that scale.
Fig. 1989 shows the method of finding the shape and position of the teeth, by the application of the
T square to Fig. 1990, as indicated by the dotted lines eeee at 2, 2, 2. The lines forming the outline
of the shaft are found in a similar manner from Fig. 1990.
The mode of drawing the curves of the top and bottom of the teeth is shown by the dotted circles,
marked ffff, and which are drawn from the centres of the teeth a a. This curve is, however, very
variable, and depends much upon the size of the pinion intended to work in the wheel.
The mortise-wheel is preferred, where a high velocity with smoothness of motion is required. It is
usually made to work into a wheel with cast-iron teeth, a pair of this sort being found to work together
with less vibration, less noise, and less wear, than when both wheels of the pair have iron teeth. For
these reasons it is very common, in good millwork, to make one wheel of every large-sized pair with
wooden cogs, especially when the speed is high, and subject to variations of velocity. But it may be
here remarked, that in cases where a very large wheel is required to geer with a smaller one, the former
is commonly made the mortise-wheel.
It may be here well to observe, that when two wheels geer together, the one which communicates
the motion to the other is called the driver or leader; and the wheel impelled is the follower. If the
two wheels be of very different sizes, the smaller one very commonly takes the name of pinion, which
may be regarded as the diminutive of toothed-wheel. For the sake of further distinction the teeth of
pinions are often termed leaves. In geering of the ordinary kinds, the pinions are commonly of the
same form of construction as the wheels with which they act; but in the old wooden machinery the
pinion is commonly formed by inserting the extremities of a number of wooden cylinders into equidistant
holes, in two parallel disks, (technically called heads and cheeks,) upon a square shaft. A pinion of
this description is denominated a trundle, lantern, or wallower, and its cylindrical teeth are termed
staves, sometimes rounds and roundles, very commonly pronounced rungs.
In early machinery the toothed wheels were often cut out of thin metal plates, which rendered it im-
possible to make a pair thus formed to work together, for the slightest deviation of one of the wheels
from the plane of rotation of the pair, would allow the teeth to lose hold of each other sidewise. To
obviate this, one of the wheels of a pair was always made either in the lantern form, as just described,
or more commonly with pins inserted at one end only, into a disk. A modification of this method also
in use, was to form the teeth on the edge of a hoop; by these arrangements, the thin wheel was enabled
to retain its hold of the teeth of the wheel with which it geered, notwithstanding a little deviation from
the plane of rotation. This form of wheel is still in common use in watch and clock work, under the
names of crown and contrate wheel.
Fig. 1992 represents the case of a wheel working into a rack, commonly called
1992.
a rack and pinion.
If the rack be curved upon the pinion it becomes an internal or annular
wheel, that is, a wheel having the teeth inside of the rim, as represented by Fig. 1993. In this the
axes of the wheel and pinion are parallel, and moreover, revolve in the same direction. The arms of
the internal wheel are necessarily situated behind the rim to prevent their interference with the pinion,
and the latter must overhang its bearing, that is, be fixed on the
extremity of its shaft, to avoid interference with the arms of the
1993.
1994.
wheel
When the pinion is made half the diameter, that is, equal in
diameter to the radius of the annular wheel, the arrangement
admits, in small steam-engines, of an application, known as
White's parallel motion. In this the annular wheel is fixed, and
the pinion is attached upon a crank-arm. The rod being at-
A.
tached at the circumference of revolution of the pinion, it is
thereby made to describe a right line, coinciding with a diameter
of the annular wheel, which is therefore equal to the length of
the stroke of the engine.
Similar combinations to that of the crown-wheel and pinion
were early introduced into mechanism. In examples of this con-
struction, which are still to be found along with cog-wheels and trundles, the cogs are simply disposed
on the rim of the wheel, from which they project in lines parallel to the axis, 80 as to geer with those
of an ordinary cog-wheel, having the cogs disposed round the circumference, or with a trundle when
1995.
1996.
one of the axes revolves much quicker than the other. This is exemplified in the hand-mill still to be
found in some parts of Germany and the north of Europe, as depicted in Fig. 1995, in which we have
the face-wheel upon the crank-axle, geering with the trundle upon the millstone axle, which forms an
angle of 90° with the former.
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GEERING.
787
In several parts of Scotland, the combination shown in Fig. 1996, as a first pair in the geering of a
thrashing-mill, is still common.
In spur-geer, the principle depends upon two cylindrical surfaces being made to act on each other
tangentially; in bevel-geer the cylinders are replaced by thin frusta of cones, which have their smooth
surfaces exchanged for a regular series of equidistant teeth directed to the apex of the cone; so that a
right line passing through the apex, if brought into contact with any part of the side, or top of a tooth,
shall touch it throughout its whole breadth; consequently in any pair adapted to work together, the
apices of their cones must meet in the same point, and thus the contact of one tooth with another will
take place along their sides. This is illustrated in Figs. 1997, 1998, and 1999.
Arm
Tooth and Space
1997
1998.
1999.
nnn
Detailed drawings of a mitre-wheel. Fig. 1997 is a section, Fig. 1998 a side view, and Fig. 1999 a
face view of a mitre-wheel. This is a kind of bevel-wheel that is used when it is required to change
the direction of motion 90° without altering its angular velocity-a case which occurs very frequently
in practice. It is obvious that only one pattern is required for the pair of wheels of this kind, and the
method of drawing any one of them will apply to both. The following is the process:
Draw a line A B equal to the diameter of the wheel, (diameter of pitch circle;) bisect A B, and pro-
duce a line at right angles to it, which will represent the centre line of the shaft. The points C and D
in this line, Figs. 1997 and 1998, where the produced centre lines of the two shafts intersect each other,
is the point to which all the lines running in the direction of the breadth of the teeth are drawn. The
distance of the point D or o from the line A B is equal to half the diameter of the pitch circle. This
will be evident if BC be drawn from the point B at right angles to A B: the line BC being equal to
A B, will represent the proper position of the other wheel, and if bisected in E, the line ED produced
perpendicular to it will be the centre line of the shaft. The point D is therefore the position of the
common apex of the two cones.
Join A D and BD, and A o and BO, and at right angles to these lines draw e m and ri, Fig. 1997,
passing through the points A and B. Make A k, Bn equal to the breadth of the teeth, and draw kg
and n h parallel to A m, BL Set off upon A m, BI the length of the teeth, as f, r 8; also the thick-
ness of rim, as fm, 8 I; and from these points let lines be drawn to the apex of the cones, as shown.
Join g h, and make q v equal to the size of the eye; Pq and V w are each to be equal to the intended
thickness of the eye, and Pt equal to the depth. Draw pt, qu, vx, wy, at right angles to gh and
join t m and y I, and thus a section of the wheel is determined, from which all the lines and points re-
quisite for drawing the plan can be found.
Fig. 1998 is a face view, the mode of proceeding with which is to transfer the points 1, 2, 3, 4, 5,
from Fig. 1997 to it, by means of the T square, which determines the extremities of the teeth and rim
circles are then described passing through these points, and that passing through the point 4 is divided
into the number of teeth intended to be in the wheel: the thickness of the teeth is then set off, and
drawn in a similar manner to that described in Fig. 1990. The lines forming the edges of the top and
bottom of the teeth are radial lines, and of course are drawn in the direction of the centre of the wheel.
Fig. 1999 the side view. The elementary lines for this drawing, viz. 6, 7, 8, 9, 10, correspond to
the lines in the section having the same figures, and the points forming the teeth are derived from Fig.
1998, by the application of the square. For example, the two points a b, forming the top of the out-
side of the tooth F, are transferred to the line marked 8, on Fig. 1999, and the points c d to the line
marked 7; these points being connected by the lines ac and bd, form the end of the tooth straight
lines are then drawn from a b in the direction of the point D, until they meet the line marked 10, and
n line in the same direction from c meeting the line marked 9. The terminations of these lines mark
out the extremities of the inside of the tooth, which being joined, complete the tooth F. The shape and
direction of the other teeth in the wheel are found by a similar operation to that used for finding F,
keeping in view that the slope of all the teeth tends to the point D.
The eye of this wheel is intended for a round boss, on which it may be keyed in the usual manner
The thickness of the web is equal to that of a tooth of the wheel; the arms have a thickness somewhat
less, and the thickness of the metal of the eye is equal to the pitch of the teeth.
The radius representing the circle of action of wheels of the kind described, is found by producing
the line BI till it meets the centre line of the shaft.
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788
GEERING.
Bevel-wheel and pinion.-This pair of wheels, shown in Fig. 2000, differs from that in the preceding,
in being of unequal size; and hence come under the denomination of bevel-wheels. Both wheels of this
pair are supposed to be placed on horizontal shafts, in which they differ from the pair of bevels in Fig.
2001, of which the pinion is placed on an upright or vertical shaft, having its bottom bearing in a foot-
step, while the wheel with which it is in geer is placed on a horizontal shaft. The mode of drawing a
pair of wheels of this kind will be understood from what follows.
Fig. 2000 is a side view of the wheel and pinion.
2000.
2001.
When only the side view of a bevel-wheel and pinion is required, it is not necessary that the whole
section, as in Fig. 1997, should be drawn, farther than to determine the position of lines a bcde and f,
and the position of the apex of the two cones, as at 0, Fig. 1997. It should also be observed, in the
example given in Fig. 1997, that the view in Fig. 1998 was requisite for drawing the side view, only
80 far as finding the position of the four points of the teeth abc d was concerned; but for common
purposes, these points can be found with sutti-
2004.
cient exactness by merely drawing circles of the
same diameter as the wheel and pinion, and
dividing them into the given number of teeth,
and marking off their thickness. This will be
readily understood, by examining Fig. 2000, in
which circles, so divided, are laid down equal
in diameter to the wheel and pinion; and 6. 7,
8, &c., show the thickness of the teeth. Now
by applying the T square, as at 6 and 7,* and
5538
marking these points upon the pitch line c, the
2003.
lines forming the sides of the teeth at 3, 4, are
found by drawing them parallel to the centre
line, which is drawn to the point where the
lines 1 and 2, forming the bevel of the ends of
the teeth, meet. This point is not shown in the
drawing, being at too great a distance for the
size of the plate. The lines forming the face of
the teeth are all drawn to the point 0 where
the cones meet, as shown by the lines gg; and
exactly the same mode is adopted in determin-
ing the shape and position of the teeth of the
2002.
pinion C.
When the wheels are drawn to a small scale,
as in Fig. 2001, the two lines forming the sides
of the teeth may both be drawn to the same
point, as shown at a, as in such cases they will
not differ sensibly from the parallel.
A bevelled mortise-wheel.-Figs. 2002, 2003,
and 2004, are plan, section, and side view of a
bevel-wheel, having wooden teeth, commonly
termed cogs. The ratio which the wheel and
pinion bear to each other is four to one, as will be observed from the section, Fig. 2003, in which A B
The scale is too small in the cut to show these figures, but the process will readily be followed by a glance at the
method pursued in Fig. 1997.
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GEERING.
789
represent the diameter of the wheel, and BC that of the pinion. By following the instructions given in
Figs. 1997, 1998, and 1999, the point D will be found to be the junction of the two cones, and conse-
quently that point to which all the lines of the teeth are drawn.
The manner of finding the points for drawing the plan, Fig. 2002, is by applying the square to Fig.
2003, as shown by the dotted lines 1, 2, 3, 4, 5, 6, 7, &c., and the shape of tooth in Fig. 2004, is pre-
cisely the same as described in Fig. 1999.
In these examples, motion is led off at an angle of 90°; but bevel-geer may be employed to change
the direction of the motion to any angle required. This will readily appear from the following dia-
grams. in which, for the sake of simplicity, we suppose the cones continued till their apices meet.
In Fig. 2005 we have an illustration of the principle of those cases already described. Here a is the
point at which the apices meet, and supposing the motion to be conveyed in the axis Aa, it is trans-
ferred to the axis a B in a right angle to its first direction.
In Fig. 2006 the change of direction is no longer a right angle; for the angle included between the
axes is obviously less than 90°, and might evidently be made still less by diminishing the angles which
the slanting sides of the cones make with their respective axes. Wheels of this kind-rather wheels
of which the angle included by the axes is less or greater than a right angle-are usually distinguished
by the name of conical-wheels.
2008.
2005.
2007.
2006.
In Fig. 2007 the apices of the two cones meet in a point, so that one of them becomes a plane sur-
face; its teeth therefore become radial as referred to its apex; in other words, they diverge in the
manner of radii, drawn from the centre a. The change in the direction of the motion is in this case
greater than 90°, and might be further increased, if consistent with the relative velocity of the pair, by
increasing the angle of the cone.
In Fig. 2008 we have an expression of a mode of changing the angle of direction differing from those
shown in the preceding figures, inasmuch as one of the cones has become hollow, and the teeth are dis-
posed upon its interior surface, thereby forming an internal bevel-wheel analogous to the internal spur-
geer previously noticed; wheels are, however, very rarely made in this manner.
2009.
When the direction approaches a right line, the cones may be made to roll upon
each other, as in Fig. 2009.
In cases where the axes do not meet in a point as hitherto considered, the geer-
ing becomes somewhat more complicated.
The direct mode of arrangement in this case is to employ an intermediate dou-
ble bevel-wheel.
To avoid the multiplication of parts, the object is more commonly attained by a
modification in the direction of the teeth, by which they are made to come into
contact in an oblique position, answering to the obliquity of the position of the
cones upon which they are formed. This artifice is often practised when it is ne-
cessary to cross the two axes,-which it must be observed are not theoretical lines but actual shafts of
diameters proportionate to the power they are required to transmit. This arrangement is represented
by Fig. 2010, and illustrates that variety of toothed-geer, known as skew-wheels. Wheels of this char-
acter are commonly avoided in practice; as, on account of the oblique form of the teeth, they are not
only of more difficult construction, and therefore rarely possess the same degree of accuracy which we
find in bevels of the ordinary sort, but the strain upon the shafts is likewise oblique, and therefore more
severe upon the bearings.
Another form of toothed-wheel, known as " Hooke's Geering," from the name of the inventor, Dr.
Hooke, consists in disposing the teeth upon the peripheries of the wheels in equidistant steps, or in
such a manner as to form a continuous slope. This remarkable contrivance, which has several times
since been re-invented and patented, was intended, to use the words of the learned inventor, First, to
make a piece of wheel-work 80 that both the wheel and pinion, though of never 80 small a size, shall
have as great a number of teeth as shall be desired, and yet neither weaken the work nor make the
teeth 80 small as not to be practicable by any ordinary workman Next, that the motion shall be 80
equally communicated from the wheel to the pinion, that the work being well made, there can be no
inequality of force or motion communicated. Thirdly, that the point of touching and bearing shall be
always in the line that joins the two centres together. Fourthly, that it shall have no manner of rub-
bing, nor be more difficult to be made than the common way of wheel-work, save only that workmen
have not been accustomed to make it."
The mode of construction contemplated by Dr. Hooke was to make the wheel and pinion of several
plates, laid one beside the other, and to bolt them together. These plates are individually cut into
wheels, which are fitted together in the manner described, but in such order that the teeth of the suc-
cessive plates follow each other in regular gradation, 80 that the last tooth of each group may, within
one step, answer to the first tooth of the next group. The pinion being constructed in the same manner,
and of the same number and thickness of plates, it is obvious that the inequalities in the touching sur-
faces are reduced in proportion to the number of thicknesses; and the amount of rubbing friction is
reduced to what it would be between the two next teeth of one of the sets.
This is still further reduced by reducing the steps formed by the ends of the teeth to a straight, or
rather a spiral edge. A wheel and pinion of this kind, observes Dr. Hooke, are equivalent to the same
having an infinite number of teeth, and are best made each of a single plate of convenient thickness,
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790
GEERING.
" which thickness must be more or less, according to the bigness of the sloped tooth And this is always
to be observed in the cutting of the teeth, that the end of one sloped tooth on the one side be full as
forward as the beginning of the next tooth on the other side;" in other words, that the end b of one
tooth on the right side be full as low as c, the beginning of the next tooth on the left side.
9010.
In a pair of wheels of this construction it is easy to perceive that the contact of the teeth will bear
every instant at a single point, which, as the wheels revolve, will travel from one side to the other, a
fresh contact always beginning on the first side immediately before the last contact has ceased on the
2011.
2012.
A
B
B
opposite side. The contact, moreover, being always in the plane of the centres of the pair, the action
is reduced to that of rolling; and as there is no sliding motion, there is consequently no rubbing friction
between the teeth.
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GEERING.
791
The motion of wheel work of this description is remarkably smooth and free of vibration, but is liable
to the objection of introducing endlong pressure upon the axes, in consequence of the obliquity of the sur-
faces of contact to the planes of rotation. To obviate this objection, the wheels have been made with dou-
ble sloped teeth, in the form represented in Fig. 2011. This wheel may be conceived to be composed of
two thicknesses of metal, each having teeth formed upon its periphery in the same manner as the wheel
of Dr. Hooke just described, and that these plates are fitted together with the direction of the teeth reverse
to each other. More strictly, the wheel may be supposed to consist of two equal and concentric plates,
which being, in the first place, made as separate wheels, have their teeth of equal size, and cut at equal
but contrary angles with the axis of rotation, are fitted together so that the teeth of the one plate meet
those of the other plate in the plane of contact. The slopes of the teeth on the two sides being thus
reverse, and projected at equal but contrary angles with the axis of the wheel, and the pinion being
formed in the same manner, the action of the respective sides of the V-shaped teeth on each other will
be as before described; but the endlong pressure arising from the obliquity of contact on one side, will
be exactly equal and opposite to that resulting from the obliquity of action on the contrary side; these
pressures must, therefore, neutralize each other, and relieve the journals of an amount of friction which
is necessarily involved in the mode of action contemplated in the original invention.
A further modification of Dr. Hooke's geering has of late been somewhat extensively adopted, espe-
cially in the newer cotton-spinning machines. This consists, when the direction of the motion is simply
to be changed to an angle of 90°, in forming the teeth upon the periphery of the pair at an angle of 45°
to the respective axes of the wheels it will then be perceived that if the sloped teeth be presented to
each other, in such a way as to have exactly the same horizontal angle, the wheels will geer together,
and motion being communicated to one axis, the same will be transmitted to the other at a right angle
to it, as in a common bevel pair. Thus, if the wheel A, Fig. 2012, upon a horizontal shaft have the
teeth formed upon its circumference with an angle of 45° to the plane of the axis, it can geer with a
similar wheel B upon a vertical axis. Let it be upon the driving-shaft; then the motion transmitted
will be changed in its direction, as if A and B were a pair of bevels of the ordinary kind, and as with
bevels generally, the direction of motion will be changed through an angle equal to the sum of the
angles which the teeth of the wheels of the pair form with their respective axes.
2013.
The contrivance, as stated, is directly a modification of Dr. Hooke's geering; but, in effect, it may be
described as a modification of the tangent screw and screw-wheel. In this last arrangement, repre-
sented by Fig. 2013, in its common form, it will be observed that the plane of the thread coinciding 80
nearly with that of the axis of the wheel, renders it necessary that the screw be uniformly the driver;
and as the screw, by one revolution, passes only a single tooth of the wheel, the motion is necessarily
slow. Both of these circumstances are manifest advantages in a large class of instances; but for very
many purposes it is desirable to retain the principle of the screw, with an increase of velocity and a
diminution of its rubbing friction. This is accomplished by diminishing the inclination of the thread of
the screw to the axis-more correctly by increasing the number of separate spiral threads upon the
surface of its cylinder; for, as every one of those spirals will pass its own wheel-tooth across the line of
centres in a revolution of the screw, it follows that as many teeth of the wheel will pass that line dur-
ing one revolution of the screw as this last has threads. If. therefore, we suppose the number of threads
to be increased until they equal in number the teeth of the wheel, then the screw and wheel may be
made exactly alike. This is precisely the case exemplified by Fig. 2012. in which we suppose A and
B to be the same size, and to have the same number of spiral teeth-which might manifestly be con-
tinued round the axes of the wheels without affecting in the least their mode of action.
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792
GEERING.
Relative direction and velocity of rotation.-A wheel describes a circle because its axis is fixed; but
the direction and the velocity of its rotation depend upon its connection with the next wheel of the
train, which lies between it and the moving power and it is evident that the relative velocities of any
given pair, must depend upon the relative magnitudes of the circles which they respectively describe.
Thus, supposing the circumference of the wheel be double that of its pinion, and, therefore, to have
double the number of teeth upon it, every revolution of the wheel must of necessity effect two revolu-
tions of the pinion about its axis. And similarly knowing the respective circumferences of any pair
acting together, it is easy to assign the ratio of their velocities. This form of the question, however,
more rarely comes into use than that requiring the determination of those quantities from the diameters,
which is slightly more involved. and renders it necessary, before entering further upon the consideration
of the subject, to examine the conditions a little more closely.
Supposing that A and B, Fig. 2014, are two axes
2014.
of motion referred to the same perpendicular plane,
Pi
and that A B is a right line connecting them. Further,
let it be supposed that the moving force is transmit-
ted through A, and that it is required to connect it
with B in such a way-that is, by a pair of spur-
OB
wheels of such sizes-that while A makes two revo-
lutions B shall make three revolutions, the distance
between A and B being six feet.
It is manifest that the circumferences of the wheels,
the axes being fixed and the circumferences in geer,
must of necessity have the same velocity. Thus,
supposing for an instant that the question is already
resolved, and that the circles described about A and
B, having their point of contact at c, then if a con-
stant force, P1, act tangentially to the circle described
about A with the radius A c, it is evident that the
rotation of this circle being transmitted to that de-
scribed about B with the radius Bc, will cause it to
describe an equal length of arc to that through which
itself passes, in any unit of time. But although the
arcs be of the same absolute length, it is easy to per-
ceive that they form very different portions of their
respective circles. In fact the arcs described by the
B
two points of a and b, taken as portions of the circle
to which they belong, are in the inverse ratio of the radii A c and Bc by which the circles are
described.
Now, if this be true for a part of a revolution, it is equally true for a whole revolution of either of
the wheels, and consequently for any number of revolutions. Hence, to obtain the radii of the wheels,
it only remains to divide the distance between the centres-that is, the line A B into parts inversely
proportional to the number of revolutions which the wheels respectively make in the same unit of
time. These rules are expressed as follows:-
I. To find the radius of the wheel, the relative number of revolutions and the distance between the
centres of the pairs being given, multiply the distance between the centres by the numbers expressing
the velocity of the pinion, and divide the product by the sum of the numbers expressing the relative
velocities of the pair-understanding by velocities the number of revolutions which the wheels make in
the same time.
IL To find the radius of the pinion or other wheel, multiply the distance between the centres by the
number expressing the velocity of the wheel, and divide the result by the sum of the velocities; or sub-
tract the radius of the wheel from the distance between the centres: the remainder is manifestly the
radius of the pinion.
Now in the arithmetical question proposed, the distance d between the centres is six feet, the velocity
of the wheel two, and that of the pinion three; hence,
6 feet 2+3 X 3 = 18 5 feet = 3 feet 7½ inches.
6 feet X 2 = 12 5 feet = 2 feet 43 inches.
2+3
Sum of radii d = R + = feet.
Having the radii or diameters of the wheels given, it is not necessary to find their circumferences in
order to determine the ratio of the velocities of their axes. The relative number of revolutions which
they will make in a given unit of time is ascertained by dividing the measure of the one by that of the
other, the quotient being the number of revolutions, or parts of a revolution, the axis of that wheel will
make which is made the divisor, while the axis of the wheel whose diameter or radius is divided makes
one revolution.
Questions of this kind may be solved very readily by means of the compasses and a scale of equal
parts. Thus let A and B, Fig. 2014, be the given centres, the ratio of their velocities being respectively
two and three, if the line joining the centres A and B be divided into 2+3=5 equal parts, that is, into
as many equal parts as there are units in the terms of the given ratio, the radius of the wheel upon A
will contain three of these parts, and the radius of the pinion on B will contain the remaining two parts,
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GEERING.
793
and the point of contact of the wheels will be at c. This method is very convenient in practice when
the terms of the ratios are small.
In the preceding examples, only a single pair has been taken; but it frequently occurs in practice
that motion is to be transferred through a system of shafts, with varying degrees of intensity, according
to the purposes to be attained. It likewise not unfrequently happens that a pair of shafts are to be
connected at such distances as to require the interposition of carrier wheels, that is, wheels intended
simply to connect the two, without being subservient to any other purpose.
Let there be two motion-axes, A and B, of which the angular velocities are as 27 to 343, and let it
be required to connect them by four wheels on two intermediate shafts, the wheels to have a common
velocity ratio throughout. Let A be the driver; then the intensity of the motion is required to increase
from 27 towards B, in which it is expressed by 343.
Now, it has been shown that if a pair of wheels be in geer, their radii are to each other as the angubar
velocities, that is, the relative number of revolutions which they make upon their axes. In order, there-
fore, that the geering pairs in the question proposed may have a common velocity ratio, it is obvious
that the same must apply to the axes upon which they are fixed. These velocities ought, therefore, to
form a geometrical progression, of which the first and last terms, (A = and B = 343,) and also the
number of terms, namely, the four axes, are given. Now, the formula for all such questions, m being
the number of geometrical means to be inserted, P the ratio, is for an increasing series.
P m+1 which becomes
Hence the angular velocity
Also, A will be connected with C, and 0 with D, and D with B by wheels of radii 7 and 3 respectively.
These examples illustrate the whole process of calculation of the transfer of angular velocity from
one axis to another, and include every case of the kind to be met with in practice.
In the case taken, we have supposed the motions of the pair to be in the same plane, and the axes of
rotation of the circles parallel. But it is often found necessary to change the direction of motion through
all conceivable angles, as in case the axes of rotation meet in a point by common bevels and face wheels,
and when the axes are neither parallel nor do they meet in direction by screw-wheels. These cases
require to be separately noticed.
Let us, in the first place, suppose that the two axes of rotation B A and CA intersect in A, and in-
clude the angle BAC. If we suppose a cone to be generated by the revolution of the line A E about
A B, and another by the revolution of the line A E about A C, then these cones
2015.
being made to revolve in contact about their respective axes A B and A C, their
surfaces will roll upon one another along their whole length of contact A E.
For, as already shown, if n times the circumference of a circle D e be equal to
m times that of a circle F e, and these circles be conceived to revolve in contact
about their centres b and c, and to carry the cones with them, then it is evident
that whilst the cone EAG makes n revolutions the cone E A H will make m
revolutions. But n times the circumference of any other circle EG of the one
cone, is equal to m times the circumference of the corresponding circle EH of
F
the other cone; for the diameters of these circles, and, therefore, their circum-
D
ferences are to one another in the same proportion as the diameters and circum-
M
ferences of the circles e D and e F. It is therefore obvious, that whilst the cones
G
make n and m revolutions respectively, the circles EG and EH are carried
B
through n and m revolutions respectively, and that n times the circumference
E
of EG being equal to m times the circumference of EH, it follows that these
circles roll in contact through the whole of their path. And the same is equally
true of any other corresponding circles in the cones, and therefore of their whole surfaces, 80 that the
rotation of one axis being communicated to the other, by the rolling together of the two cones, the sur-
face of the one cone will carry with it the surface of the other along the whole line of contact A E with
equal perimetral velocities, and with angular velocities inversely proportional to the circumferences,
diameters, or radii, of the corresponding circles.
In practice, thin frusta only of the cones, with teeth upon their perimeters, are employed; but in
this there is no new consideration involved, as respects the angular velocities of the axes upon which
the wheels are carried. In determining the size of a pair of bevels, we are not, however, limited to any
particular diameters as when the axes are parallel; the wheels may be made of any convenient sizes,
and the teeth consequently of any breadth, according to the stress they are intended to bear.
The question, however, which presents itself here, is the mode of determining the relative sizes of the
conical frusta of a pair; and this resolves itself into a division of the angle included between the two
axes inversely as the ratio of their angular velocities. Let B and C be the position of the two given
axes, and let them be prolonged till they meet in a point A. Further, let it be required that C make
seven revolutions while B makes four. From any points D and E in the lines A B, A C, and perpendicular
to them, draw Dd and E e of lengths (from a scale of equal parts) inversely as the number of revolu-
tions which the axes are severally required to make in the same unit of time. Thus, the angular velocity
of axis B being 4, Fig. 2016, and that of the axis C being 7, the line Dd must be drawn = 7, and the line
Ec=4 Then through d and B parallel with the axes A B and A C draw d and till they meet in
100
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794
GEERING.
c. A straight line drawn from A through c will then make the required division of the angle B A 0,
and define the line of contact of the two cones, by means of which the two rolling frusta may be pro-
jected at any convenient distance from A.
Otherwise, having determined the relative perimeters,
2016.
diameters, or radii, of the pair, then the lines D d and E
are to each other directly as these quantities.
The point c may also be found more directly thus: From
A towards C in the axis A C, set off from a scale as many
equal parts (Af) as there are units in the number (7) ex-
pressing the velocity of that axis; from the point f draw
fc parallel to A B, and set off from the same scale as
many parts (fc) as there are units in the number (4) ex-
pressing the velocity of the axis A B; then a line drawn
from A through c, as before, will divide the angle, as required.
By one or other of these methods the division of the
angle of inclination of the axes may always be determined,
the ratio of the angular velocities of the pair being known.
The case in which the axes are neither parallel nor inter-
secting, admits of solution by means of a pair of bevels
upon an intermediate axis, 80 situated as to meet the others
in any convenient points.
Thus, if DF and EG, Fig. 2017, be the two given axes,
they may be connected by a third axis FG intersecting them
in the points F and G; and if a shaft be mounted in the posi-
tion of this third axis with a pair of bevels upon it, geering
with the bevels on the main axes, and having their apices
in the points F and G of these axes, the motion of the driving-
shaft will be communicated, as if the two bevel-wheels C and M were in immediate contact; the ratio
of their velocities remaining the same, provided the bevels H and K be of the same size. If it be re-
quired to bring up the speed or reduce it, between the two shafts, in a higher ratio than is convenient by
that arrangement, the interposed bevels will afford additional facility of accomplishing the purpose.
When the contiguity of the shafts is such as to per-
2017.
mit of their being connected by a single pair, skewed-
bevels are frequently employed as shown in Fig. 2010;
and as respects the relative velocities of a pair of this
kind, it is evident that the same law obtains as in the
F
preceding cases.
When the axes are at right angles to each other, and
H
do not intersect, the wheel and screw may be em-
ployed to connect them. The velocity of angular
c
motion is in this arrangement immediately deduced
from that of the screw, its number of threads, and the
number of teeth in its geering wheel. Thus, if it be
required to transmit the motion of one shaft to another
contiguous, and at right angles to it-the angular mo-
tions being as 20 to 1; then, if the screw be a single-
threaded one, the wheel must have 20 teeth; but if
double-threaded the number of teeth will be increased
M
to 40, for 2 teeth will be passed at every revolution.
If the velocities be as 2 to 1, the condition is, that the
screw have half as many threads upon its barrel, as
D
there are teeth on the wheel; and if 1 to 1, the wheel
and screw lose their distinctive characters: both be-
come many-threaded screws under the form of wheels,
E
as represented by Fig. 2011. Wheels of this sort may
often be applied with peculiar advantage, especially in light geering; and when 80 applied it is not
essentially necessary that the axes be at right angles to each other any more than it is in bevel-geer.
If the screw have few threads compared with the number of teeth of the wheel, it must always
assume the position of driver on account of the obliquity of the thread to the axis; and in this respect
its action is analogous to that of a travelling rack, moving endwise one tooth, whilst the screw makes
one revolution on its axis.
On the pitch of wheels.-The primary object aimed at in the construction of toothed-geer is the uni-
form transmission of the power, supposing that to be constant and equal This implies that the one
wheel ought to conduct the other, as if they simply touched in the plane, passing through both their
centres. This plane is denoted by the line A B, in Fig. 2018.
When this line-which is usually denominated the line of centres-is divided into two parts. A c and
Bc, proportional to the number of teeth formed upon the perimeters of the pinion and wheel, these two
parts are proportional or primitive radii of the pair; and a circle CC being described from each centre
passing through the common point c, limite what is called the pitch line or circle; that is, a circle de-
scribed from the centre A, and another from the centre B, through the same point, are called, the first,
the pitch circle or pitch line of the pinion, and the other of the wheel. They are also sometimes called
the primitive and proportional circles. If the pitch circle be divided into as many equal parts as there
are teeth to be given to the wheel the length of one of these parts is termed the pitch of the teeth.
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GEERING.
795
One of these arcs, as that intercepted by pp in Fig. 2018, comprehends a complete tooth and space,
meaning by space the hollow opening between two contiguous teeth.
B
C
R
R
2018.
By the pitch lines of a geering pair is, therefore, to be
D P X N
N
X
understood the proportional circles in which they would
*
revolve upon each other if they were simply cylinders
Pitch in inches
RULE.-To And the
RULE. -To find the
without teeth; and the pitch of the teeth is the length
and parts of an
diameter in inches,
number of teeth, mul-
inch.
multiply the number
tiply the given diam-
of are of the pitch circles, measured from the centre of
of teeth by the tabu-
eter in inches by the
one tooth to the centre of the contiguous one. Any right
lar number answer-
tabular number an-
ing to the given pitch.
swering to the given
lines, P and P, drawn from the centre of the wheels till
pitch.
they meet the pitch circles or lines, are termed propor-
tional radii, because they determine the relations of their
P
*
Values of P
Values of
Values of
angular velocities; and any similar radial lines, P' and
*
P
P', continued to the extremities of the teeth, are called
the true radii of the wheel and pinion-for no very ob-
6
19095
5236
vious reason. In bevel and conical wheels the pitch cir-
5
15915
6283
cle is the base of the frustum, as AB of Fig. 1997.
41
14270
6981
Rules.-L To find the pitch of the teeth of a wheel,
4
1.2732
-7854
the diameter and number of teeth being given, divide
31
1.1141
8976
the diameter D, (in inches,) by the number of teeth N,
8
9547
10472
and multiply the quotient by 3.1416: the product is the
pitch in inches or parts of an inch.
21
8754
1-1333
II. To find the diameter of a wheel, the number of
21
7958
1.2566
teeth and pitch being given, divide the pitch by 3-1416,
21
7135
1'3963
and multiply the quotient by the number of teeth.
2
6366
15708
III. To find the number of teeth, the diameter and
pitch being given, divide 3.1416 by the pitch, and multi-
1½
5937
1.6755
ply the result by the diameter in inches.
11
.5570
1.7952
In ordinary geering the pitches most commonly in use
13
5141
1.9264
range from 1 inch to 4 inches, increasing up to 2 inches
1f
.4774
2.0944
by eighths, and beyond by fourths of an inch. Below
1]
4377
2.2848
inch, the pitches decrease by eighths down to t inch.
11
3979
2.5132
The pitches being few and definite, the rules given
1f
3568
2.7926
above may be greatly simplified by the use of the an-
1
3183
3.1416
nexed table, which will be found very convenient when the
diameter D is to be determined, the pitch P and number
-2785
3.5904
of teeth N being given; and conversely, when the diame-
4
2387
4'1888
ter and pitch are given to find the number of teeth.
a
1989
50266
The use of this table may be rendered obvious by the
1592
6.2832
following examples :-
1
-1194
8.3776
1. Given a wheel of 88 teeth, 21-inch pitch, to find the
0796
125664
diameter of the pitch circle. Here the tabular number in
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796
GEERING.
the second column answering to the given pitch is 7958, which, multiplied by 88, gives 70.03 for the
diameter required.
2. Given a wheel 33 inches diameter, 14-inch pitch, to find the number of teeth. The corresponding
factor is 1.7952. which multiplied by 33 gives 59-242 for the number of teeth, that is, 591 teeth nearly.
Now, 59 would here be the nearest whole number; but as a wheel of 60 teeth may be preferred for
convenience of calculation of speeds, we may adopt that number and find the diameter corresponding.
The factor in the second column answering to 11 pitch is .557, and this multiplied by 60 gives 33.4
inches as the diameter which the wheel ought to have.
A mode of sizing wheels in relation to their pitches, diameters, and numbers of teeth, is adopted in
some engineering factories as a simplification of that explained above.
Suppose the diameter of the pitch circle to be divided into as many equal parts as there are teeth to
be given to the wheel; let one of these parts be called the diametral pitch, to distinguish it from the
circular pitch hitherto employed, and let a few definite values (in terms of the inch) be assigned to it;
then it is clear, that calling M the diametral pitch, we have the relation N=M And as M is always
a simple fraction of an inch, let M=1/, then we have the general expressions,
N
N=mXD
D=N
To illustrate this by an arithmetical example, let it be assumed that a wheel of 20 inches diameter is
required to have 40 teeth; then the diametral pitch,
that is, the diameter being divided into equal parts corresponding in number to the number of teeth in
the circumference of the wheel, the length of each of these parts is 1 an inch, consequently m = 2; and
according to the phraseology of the workshop, the wheel is said to be one of two pitch The circular
pitch corresponding to this diametral pitch is by the properties of the circle 3 X 3.1416 = 1.5708
inch.
In this mode of sizing wheels a few determined values are given to m, as 20, 16, 14, 12, 10, 9, 8, 7,
6, 5, 4, 3, 2, 1, which includes a variety of pitches from 16 inch up to 3 inches, according to the following
table, which shows the value of the circular pitches corresponding to the assigned values of m.
Values of m.
1
2
3
4
5
6
7
8
9
10
12
14
16
20
Corresponding circular
pitch in decimals of an in.
}
3.142
1.571
1047
-785
628
524
449
393
.349
314
.262
.224
-196
.157
From this table, having the value of m given, the corresponding circular pitch is found; and from the
rules given above, if the number of teeth and value of m be known the diameter of the wheel is also
known, for D=N÷m. Thus if the number of teeth be 80 and m = 10, then the diameter D=8
inches, and the circular pitch is 314 inch, that is, 5-16th inch very nearly. Generally, the diameter and
value of m being given, the number of teeth is found from the rule N =m X D. Thus the value of m
being 10, and the diameter 20 inches, the number of teeth is 200.
From these remarks, it is easy to perceive that this mode of sizing wheels differs from that before
explained simply in this, that it expresses in small whole numbers the quantity * | P instead of the quan-
tity P, and therefore affords a ready way of calculating the diameter and number of teeth of any re-
quired wheel. This method, however, has not hitherto been introduced into millwright work; but has
been confined to the sizing of small wheels of spinning and like machinery.
It has long been regarded as a rule among millwrights that the number of teeth in a wheel should
be prime to the number of teeth in its pinion; in other words, that the number of teeth of the wheel
should not be divisible by the number of teeth in the pinion without a remainder; and that the best
possible relation of the numbers is such, that in effecting the division the remainder be 1. This one is
termed a hunting tooth, and effects the purpose of preventing the same pair of teeth of the wheel and
pinion from coming together until the former has made as many revolutions as it has teeth. By such
an arrangement it is supposed the wear would be less uniform; and it may be observed, that if the
teeth be at first incorrectly made, there is some advantage to be gained by taking prime numbers.
But in the practice of the present day, when millwrights are fully alive to the method and advantages
of giving to the teeth, in the construction of their wheel-patterns, the proper geometrical form. and do
not trust to the wheels wearing themselves into shape, the precaution of making the numbers of the
wheel and pinion prime to each other, is less required, and may, in fact, be disregarded in proportion
as accuracy of construction is attained.
In respect of the relative sizes of the pairs which geer together, the main purpose to be accomplished
is the modification of the contemporary velocities of the parts to such extent that their respective speeds
shall be adapted to the work to be performed at the several points.
To exhibit the method of applying the principles of angular velocity to the computation of the num-
bers of a system of toothed geering, we shall consider, in the first place, the action of a single pair.
The fundamental proposition may be stated thus :-If there be an equal pair in geer, then whether the
pinion drive the wheel or be driven by it, the number of turns of the wheel multiplied by the number
of its teeth, is equal to the number of turns which the pinion makes in the same time, multiplied by
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GEERING.
797
the number of its teeth, so that the number of the contemporary turns of the wheel and pinion are re-
ciprocally proportional to the numbers of their teeth.
Applying this principle to a system of geering, we deduce the following rules: To find the number
of revolutions of the last pinion of the system, multiply the number of revolutions of the first wheel by
the quotient which is found by dividing the continued product of the numbers of teeth of all the wheels,
by the continued product of the numbers of teeth of all the pinions.
It thence also follows that the number of revolutions of the last pinion, for one revolution of the first
wheel, is equal to the product of all the wheels divided by the product of all the pinions.
And conversely for one revolution of the last pinion, the first wheel will make that portion of a revo-
lution expressed by a fraction, having for its numerator the product formed by multiplying together the
numbers of the teeth of all the pinions, and for its denominator the product formed by multiplying to-
gether the numbers of teeth of all the wheels.
From these rules it immediately follows, that whether a system of geering contains one wheel and
pinion, or any greater number of wheels and a like number of pinions, if we designate the product of all
the wheels by W, and the product of all the pinions by P, and if p represent the number of revolutions
made by the last pinion during one revolution of the first wheel, we shall have
W
In reference to the strength of the teeth of wheels, the first subject of inquiry is the stress they are
severally required to sustain when in action.
The fundamental principle involved in the consideration of this subject, is expressed by the condition
that the pitch being the same, the stress is inversely as the velocity; and this is obviously true, since the
teeth which act with superior force must be proportionally stronger; and the momentum of the power
remaining constant, the higher the velocity becomes, the more is the weight of the power diminished,
80 that in any combination of wheels, the stress upon the teeth is reciprocally proportional to the ve-
locity at a given point of the train. Thus, the strength which is sufficient to transmit a given amount
of horse power, when the velocity is one foot per second, will be equal to the transmission of double
that amount when the velocity is two feet a second, three times the amount when the velocity is tripled.
Knowing therefore the strength of teeth necessary to transmit a given amount of horse power, the same
strength of wheel will be sufficient under any other circumstances of increase, or diminution of velocity,
when the horse power of the first mover in both cases, divided by the velocity in feet per second, pro-
duces the same quotient. Thus assuming as the standard the received mechanical unit of a horse
power, namely, 33,000 pounds raised one foot high in a minute, or 550 pounds raised one foot in a
second, then if H be the number of horses' power of any first mover, and v the velocity of the pitch
circle (in feet per second) of any wheel in the system of geering moved by it, then the stress will be
expressed in pounds by 550 X H
v
For example, if the pitch line of a wheel move with a velocity of 11 feet per second, and the power
of the prime mover be twenty-horse power, the stress will be 550 11 X 20 = 1000 pounds.
Otherwise, if P be the power of the prime mover in pounds, and V be the velocity of that power it
feet per second, the stress on the teeth of a wheel through which the power is transmitted, and of which
P X V
the velocity of the pitch circle is v, will be expressed in pounds as before, by
v
It is necessary, however, to be observed, that the absolute power of the prime mover must only be
considered at those points of the geering through which it is wholly transmitted; for if the power be
taken off at different points, it is obvious that the stress will be successively diminished as these points
are passed. For instance, the power of a steam-engine being employed to drive a cotton factory if the
first geering be 80 arranged that the whole power of the engine is transmitted from the fly-wheel shaft
to a vertical shaft, which ascends from the bottom to the top-flat of the building, by a bevel pair, and if
the geering of the several flats be successively connected with this upright shaft, it is clear that, in esti-
mating the stress at the several points, with a view to ascertaining the requisite strength of the several
pairs, the whole power of the engine ought to be taken only at the first point; that is, at the point
where it is connected with the vertical shaft. In estimating the strength of the bevel pair there placed,
H, in our formula, will be equivalent to the whole power given off by the engine; but at the successive
points, where the power is taken off to drive the machinery of the several flats, H will represent only
the amount of power requisite to do the work at these points.
A difference is besides very properly made in practice, in the strength of those wheels of a system of
geering which are placed near the first mover, to compensate for irregularities in the motion; for were
the strength exactly limited to the resistance to be overcome under constant action, a sudden accelera-
tion of the speed would tend to stripe the wheels, in other words, to break the teeth. Also in operations
of an irregular kind, the strength ought to be greatly more than is requisite in such geering as that of
a cotton factory. Thus the geering in iron-works, and the like, is greatly beyond the strength which a
calculation of the power of the prime mover would indicate, and this is required to counteract the sud-
den shocks which result from the chocking of rolls and the like.
It may also be necessary to remark, that, in estimating the strain upon a system of geering, it is the
actual power required to do the work which is to be taken as an element of the data-that is, the horse
power at which the resistance is valued.
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798
GEERING.
In the teeth of wheels, it is of importance that the whole be made of such strength as to sustain un-
injured the greatest stress that is likely to come upon it in the course of working in the worst possible
position; that is to say, in the direction in which the
3
structure is capable of offering the least effective resist-
D
ance to fracture. Now supposing the strain to act with
its whole energy upon the extreme corner of a tooth, it
is easy to perceive that it will there more readily pro-
2019.
duce fracture than if it acted along the whole line of the
breadth; for supposing it to act along the whole line of
B
breadth, if fracture of the tooth should take place, it
must traverse the whole line A B, or some line parallel
to it; but acting at D, should the force be sufficiently
great to break the tooth, the fracture will take place,
not along the root of the tooth A B, but in the line B b,
or in some line parallel to it-these being the lines of
least resistance. Rather, under the circumstances of
the force being applied at D, the strain will be greatest along the line Bb, which is defined from
BD=Db.
To show that this is strictly true, let it be borne in mind that the strength of beams of equal thickness
is directly as their breadths, and inversely as their lengths; consequently, if the proportion of the length
to the breadth be preserved, the strength will remain unaltered whatever difference is made in the
actual dimensions. But this being true, it necessarily follows that the line of fracture, under the cir-
cumstances presumed, will be along the line which, as a base, bears the least proportion to the perpen-
dicular height from that base to the point where the pressure is applied. This least proportion is when
B D = D b, for the base Bb is then only double the effective length of the beam, that is, double the
perpendicular e D. If a line be drawn from B to d, it will manifestly be more than double the altitude
of the triangle B d D, of which it is the base ; and, similarly, the line B c is more than double the alti-
tude of its triangle B c D.
This might be directly proved by application of the rules of maxima and minima rather, it might be
shown that the strain is greatest under a force acting at D, in a line determined by DB=Db, which
makes B b = 2 e D.
In effect, therefore, the line Bb (including all lines parallel to it) is the line of least resistance of the
tooth, and consequently the line in which fracture would be produced by a force sufficiently great ap-
plied at D. Presuming, then, that wheels, in consequence of inaccuracy of workmanship, unequal
wearing of brasses, vibration of shafts, and other circumstances incidental to the action of a system of
geering, are liable to stress acting upon them in the least efficient position of the teeth, it would appear
that the effective proportion of the breadth of the tooth, assuming the thickness to be uniform, does not
exceed twice the length. Whatever may be the force, the principle informs us that there is a limit be-
yond which no strength is practically gained, and this limit will be found in general not to differ
materially from double the length of the tooth.
It must not, however, be inferred from this that it is useless to make the breadth of any proportion
greater than that stated for although no additional practical strength be gained by increase of breadth,
it is still highly advisable that the dimensions named should bear a much higher ratio, than is given by
the consideration of the merely mathematical principle. This is accordingly followed in practice, and
the advantage is, that the wearing action, by being distributed over a larger surface, does not so soon
reduce the thickness, and thereby render the wheel too weak for the work it has to perform. Moreover,
there is the additional advantage in giving more breadth than is indicated above, that the surfaces OI
contact being longer, vibration is to some extent diminished; the centres are accordingly better pre-
served, and the wearing of the tooth becomes greatly more uniform. An error of workmanship, and
of unequal contraction of the casting, becomes likewise more apparent, and may possibly admit of
correction.
2020.
Ox3
P
P
As it is convenient to express all the dimensions in terms of the same unit, and the pitch being an
appropriate quantity, is nearly universally adopted as the term of comparison.
These proportions differ, though slightly, in different works and in different localities; but they are
the most commonly employed, and are besides the most consistent with good and accurate workman-
ship. For the sake of more easy reference, we collect them into a table, which the annexed Fig. 2020
will serve fully to explain. They stand thus:
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GEERING.
799
= Pitch of teeth,
= 1 pitch.
"
ac = Depth to pitch line, PP, =
a X a = Working depth of tooth, = 6
"
"
C - A a = Bottom clearance,
=
10
"
Ca= Whole depth to root,
=
10
"
Cb = Thickness of tooth,
=
"
b = Width of space,
IT
These proportions, as remarked, are found to work very advantageously, and are those adopted in
several workshops; but the following are preferred by some engineers of experience. Thus supposing
the pitch divided into 15 equal parts: then the
Depth from point to pitch line,
= 53 parts.
Depth from pitch line to root of tooth,
= 61 of
Whole length of tooth,
= 12 "
Working depth,
= 11
as
Thickness of tooth, (also of arms and rim,) = 7
"
Width of space,
= 8
"
.
In practice, these proportions are usually laid off in lines for the convenience of the workmen in the
pattern shop, so that for any given pitch the other dimensions may at once be determined by means of
the compasses, and without having recourse to calculation. In Figs. 2021 and 2022 two diagrams of that
sort are given. Fig. 2021 contains the proportions last enumerated, in which the pitch is supposed to be
divided into 15 equal parts; and Fig. 2022 is constructed nearly according to the proportions first given,
but embraces the recognized principle that the relative amount of clearance ought to vary inversely as the
pitch, wheels of small pitch requiring more clearance relatively than those in which the pitch is greater.
Accordingly, in this scale, the clearance in a wheel of 4-inch pitch is 1-10th the pitch, whereas were the
scale sufficiently extended, it would show a clearance of only 1-18th for a pitch of six inches.
The construction of these scales is very simple. Thus in Fig. 2021, and to six inches pitch, let A B
be divided into 15 equal parts, and draw BC perpendicular to it; and again divide BC into a
determinate number of parts from B, actual measures of the pitches for which the scale is intended
to be used that is, B a = t inch; Bb = 1 inch; B = 2 inches, and so on, and join a and A, b and A,
e and A, and so on. To complete the scale, draw 15 parallels to BC from the points numbered in the
line A B, numbering their intersections (if thought proper) with the line A C in the same order; and
also the two parallels T and U, (which are full lines in the diagram,) equidistant from the parallels on
each side of them.
The scale is thus ready for use, and its principle is evident. To get from it the several propor-
tions for a given pitch, say of 8 inches = Bd, let the compasses be extended from the intersection of the
parallel marked T, with the line A B, to the point where it intersects the line A d; this will be the part
of the tooth from the pitch line to the point, and equivalent to 57 parts of the pitch, (viz. of B d;) sim-
ilarly the compasses being extended from the intersection of the parallel U, with the line A B, to its
point of intersection of the line A d, will give the part of the length of the tooth from the pitch line to
the root, and equivalent to 61 parts of the pitch. For the whole length of the tooth (if wanted in one
measurement) set the compasses to the point where the parallel marked 12 meets the line A B, and
extend to its point of intersection of the line A d at 8, the length is 12 parts of the pitch Bd; the work-
ing depth is in like manner found from the parallel marked 11; the thickness from that marked 7; and
the width of space from that marked 8.
The proportions for any other given pitch comprised in the scale are found in precisely the same way,
and if the scale be well constructed they may be measured off with the utmost accuracy and readiness.
To save confusion it is, however, better in practice to insert in the diagram only those parallels, namely,
T, U, 12, 11, 8, 7, which are required the others are not requisite, and by inattention may lead to error.
Both this scale and that marked 2 are commonly drawn on hard-wood boards; but sometimes, for the
sake of greater accuracy, on plates of polished brass.
The description of the scale as here given supposes that the lateral clearance is constantly 1-15th of
the pitch; but as it is commonly desired and desirable that this should vary slightly with the pitch,
relatively increasing as the pitch decreases, two other lines, m n and pq, have been introduced into the
scale, to enable such modification to be adopted, should it be required. These lines are drawn at such
angles as to give a clearance at 6 inches pitch of 1-18th, which is increased at 4-inch pitch to 1-10th.
From these lines the thickness and space are to be taken, instead of using the lines marked 7 and 8,
setting the compasses in the points of intersection with the pitch lines, and extending perpendicularly
to the line A B; in other words, the shortest distance from the point of intersection with the pitch line
to the line A B, is the required measure of the space when the line pq is taken, and of the thickness of
tooth when the line m n is taken.
Fig. 2022 is more complete than the one described, and when well constructed insures, with moderate
care, a degree of accuracy and uniformity, in the construction of the various sizes of wheels for which it
is employed, that can hardly be otherwise attained. The principle of its construction is in effect the
same as that described, but its use is more extended; the diameter of the wheel being found from it
simultaneously with the length and thickness of tooth, width of space, and clearances. The scale is
adapted to wheels of all the pitches enumerated in the table, p. 795, from 1 inch up to 3 inches. The
mode of construction is this: having drawn the line AD of any convenient length, raise the perpendic-
ular CB to it, also of any convenient length. On the line A D lay off the greatest pitch of the scale
from C to A; then from C towards D lay off seven times the pitch once or twice, according to the sizes
of wheels to which the scale is intended to be applied. In the scale given, double of seven times the
Digitized by Google
800
GEERING.
pitch is laid off, namely, 42 inches; then each of these great divisions being subdivided into 11 equal
parts, one of these parts will be equal to four teeth upon the radius of the wheel, so that the whole line
CD will be divided into 88 radial pitches. Next on the line CB set off the pitches which may be re-
quired in the scale, and through these points draw the 24 parallels to A D, terminating in the lines A B
and DB. Then each parallel measured from the line BC to its point of termination in BD, is the
radius of a wheel of 88 teeth of the particular pitch marked against it on the line AB. They also
express the radii of wheels having less than 88 teeth when measured only to the corresponding point
in the line joining B, and the divisional on CD, against which the number of teeth is marked. Thus
the radius of a wheel of 52 teeth and 1 f-inch pitch, is T8= 15 7-16th inches very nearly. (The true
answer by the table, p. 795, is 308724 ÷ 2 = 154362 inches.)
PROPORTION SCALES FOR GEERING.
a
b
c
d
2021.
B 1/1%
1
1½
2
2½
3
3½
15
4
4½
5
5½
C
B
2022.
½
14
1/4
13
%
12
1/2
%
11
%
10
½
9
1
P
1½
8
1
1%
n
7
m
1%
0%
U/
0
1½
6%
1%
5
1%
4
1%
3
2
2½
2
2%
,
2%
2½
A
2%
2%
2%
D
A
88
84
8:0
7.6
72
68
61
GO
5.6
52
48
44
40
36
3 :
2:8
24
20
1,5
12
8
4321
all
22
21
20
19
18
17
16
15
11
13
12
11
10
9
8
7
6
5
4
3
12
1
14
13
12
11.
10
9
S
7
6
5
4
3
2
1
The scale may also be used when the number of teeth exceeds 88; for example, to find the radius of
a wheel having 100 teeth. Thus having found the radius answering to 88 teeth, upon the same parallel
take off the measure answering to the difference 100 - 88 = 12 teeth; and the two measures together
will be the radius required.
To adapt the scale to odd numbers of teeth, the first division on the right of C is divided into single
radial pitches, 80 that the radius of any wheel may be measured off without baving recourse to calcu-
lation of any kind. Thus, for example, if the wheel is intended to contain 50 teeth, the compasses being
Digitized by Google
GEERING.
801
extended from 52 to the intersection of the parallel answering to the particular pitch to where it meets
the line joining Q and B, will give the radius required, that is, a radius answering to 52 - 2 = teeth;
and any other number of teeth when not marked against the base may be found in the same way, ob
serving that it is more convenient to subtract than to add in this use of the scale.
For the proportions of the teeth, set off a = 7-tenths of the pitch, then will A a = 3-tenths of the
pitch, which corresponds to the depth from the point of the tooth to the pitch line. Again, set off
= 7-fifteenths of the 3-inch pitch, and 5-elevenths on the parallel against the 1-inch pitch; this will
be the thickness of the tooth, allowing from a fifteenth for clearance on the largest pitch, to a tenth on
those from f-inch and under; and A b will be the width of space, including the clearance. Lines being
drawn from those points to B complete the diagram, which will be found to contain all the proportions
enumerated in the preceding table.
To use the scale, lay off the addendum of the tooth; that is, the length beyond the pitch line, equal
to A a = in pitch, and the same length marked off within the pitch line will give the whole working
depth of the tooth, namely, 6-10ths pitch. Then with the measure C a = T⁷₀ pitch in the compasses,
mark off the whole length of the tooth, and this will allow 1-10th at bottom for clearance. Again, set
off the thickness of tooth = C b, and the space = b which will contain the clearance for the particular
pitch, varying from 1-15th to fully 1-10th on the small pitches. It is hardly necessary to observe that
these measurements must be taken upon the parallel corresponding to the particular pitch under con-
sideration at the time.
The amount of bottom clearance is here presumed to be uniformly 1-10th of the pitch; but if it be
thought advisable to make this vary as in the case of the lateral clearance, it will then be necessary to
insert a third line c B in the scale, and 80 related to a B that the space a c shall be throughout equal to
the depth of tooth from the pitch circle to the root, and giving any bottom clearance that may be desired.
In relation to the strength of wheels, M. Morin, in his Aide Mémoire de Mécanique Pratique, gives it
as a rule that when the velocity of the pitch circle does not exceed five feet per second, the breadth of
the tooth measured parallel to the axis ought to be equal to four times the thickness; but when the velo-
city is higher the breadth ought to be equal to five thicknesses, the teeth being constantly greased. If the
teeth be constantly wet, he recommends the breadth to be made equal to six thicknesses at all velocities.
With respect to the thickness of the tooth, it is plain that it must be dependent on the pressure which
the tooth is required to sustain. This relation may be conveniently expressed for all cases by the formula,
= o W. where t is the thickness of the tooth, W the pressure upon it in pounds, and c a constant
multiplier depending upon the nature of the material of which the tooth is formed.
Therefore for cast-iron c = 025; and reasoning in the same way for brass, we find it = 035 for hard
wood, = 038; so that for the thickness of teeth of these materials, we have,
For
cast-iron,
t=025 √W
For brass,
t=035 √W
which give t in inches or parts of an inch,
For hard wood, = 038 W
W being taken in pounds.
As an example of the application of these formulæ, let it be required to find the thickness of a tooth
(cast-iron) which is to sustain a pressure of 4000 pounds at the pitch circle, the breadth being double
the length.
Here W = 4000; therefore W = 63.25.
Hence t = 025 W = 025 X 63.25 = 1.58 inch.
The same calculation applied with the formula for brass, would give t = 2.21 inches; and for wood
it gives t = 2.4 inches.
The thickness of tooth given by our rules is intended to make allowance for wear at a velocity of
three feet per second, and has been found to be sufficient in practice. It is, however, less by a small
fraction than would be found by application of Mr. Tredgold's rule; that is, divide the stress at the
pitch circle in pounds by 1500, and the square root of the result is the thickness of the tooth in inches.
To compare this rule with that given above we subjoin the following table, which will likewise be
found useful in calculating the strength of wheels.
Thickness of teeth.
Stress in lbs. at
Actual pitches to
Corresponding thickness, al-
the pitch circle.
By Author's
which the wheels
By Tredgold's
would be made.
lowing 1-10th for clearance.
rule.
Rule.
lbs.
Inches.
Inches.
Inches.
Inches.
400
0.50
0.52
1g to 11
0536 to 0.593
800
0-71
0-75
11 - 11
0.714 0774
1200
087
0.90
11 - 2
0.893 0.952
1600
100
103
2 - 21
0.952 1012
2000
1.12
1.15
24 - 21
1031 1.132
2400
1.22
1.26
21 - 21
1.190 1.250
2800
1'32
1'86
21 - 21
1.250 1.309
3200
141
1'43
21 - 8
1'369 1429
3600
150
1.56
31 - st
1-488 1548
4000
1.58
163
31 - 81
1548 1607
4400
1·66
170
31 - 31
1607 1.667
4800
178
178
31 - 84
1667 1.726
5200
180
186
31 - 34
1726 1.786
5600
187
193
34 - 4
1-786 1.904
6000
194
200
4 - 41
1904 2024
101
Digitized
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802
GEERING.
The last column of this table is calculated from the expression pitch t. = (2 + to) = 2.1t. the clear-
ance being a tenth. The thickness, allowing 1-15th for clearance, may in like manner be calculated
from the expression pitch = t. (2 + 1'3) = 2067
The formula reduced to expressions giving the pitch p in the same manner as the thicknesses are
given above, will stand thus :-
Clearance a tenth.
Clearance a fifteenth.
For cast-iron teeth P 0525 W and p = 0517 W.
For brass teeth 0735 W and p = 0723 W.
For wooden teeth p = 0798 W and p = 0785 W.
By means of these rules the pitch may be directly calculated. Thus, for a pressure of 15,000 pounds
we have,
W = 15,000 = 122.5.
Consequently, the pitch of a cast-iron wheel capable of sustaining that pressure at the pitch circle,
allowing 1-15th for clearance, will be
0517 W = 0517 X 122.5 = 6'333 inches.
The wheel from which this example is taken has been several years in action, and has an actual pitch
of six inches, and the mean pressure at the pitch circle is 14786 pounds.
It may be here observed that it is common, in calculations relative to the strength of the teeth of
wheels, to make additional allowance for wear of the pinion; for if the pinion make double the number
of revolutions made by the wheel with which it is engaged, its teeth will manifestly be subject to double
the amount of wear by friction; consequently, to proportion the teeth of the pair 80 that they shall
wear equally long, it is necessary to give an allowance of thickness on those of the pinion equivalent
to the increase of abrasion to which they are subject. If we assume one-third the thickness as the
proper allowance, this will give for the thickness of the pinion the expression 3 , in which n is
the number of revolutions which the pinion makes for one revolution of the wheel, and t the thickness
of the teeth of the wheel. Thus, for example, if the pinion make 21 times as many revolutions as the
wheel, of which the thickness of the teeth is 1-12 inch, then the thickness of those of the pinion will be
3 3 = 168 inch.
This amount of difference, is not, however, commendable in practice. at least in spur-geer, and it is
therefore rarely adopted, as wheels would in that case require to be constantly made in pairs, which
would lead to an endless accumulation of wheel patterns. Instead of making the allowance spoken of,
the common practice is to adopt a larger pitch-rather, indeed, to use wheels somewhat beyond the
strength which is requisite for the work.
It has already been shown that by a horse power is meant a pressure of 33,000 pounds moved with
a velocity of one foot in a minute. But this is the mean of the force exerted, and as most prime movers
are more or less variable in their motion, any wheel required to transmit that motion should be strong
enough to bear the maximum force with safety. For ordinary and general purposes we may assume,
as a very safe approximation, that it exceeds the mean of the whole force exerted by the fraction
3-11ths. Making that allowance, we shall have, as the practical strain of a horse power, 550 lbs. X
1 = 700 lbs. raised one foot per second. By substitution of this value of the horse power, in the rule
formerly given, it will become '700 X H = the stress on the teeth of the wheel in pounds.
v
As an example, let a steam-engine of 12-horse power be applied to drive the machinery of a factory.
and let it be required to find the strength of the teeth of a first wheel on the main shaft, which will
have a velocity of four feet a second, at the pitch circle.
Here H = 12 and v=4; therefore 700 X H = 700 4 X 12 = 2100 lbs., the pressure at the pitch cir-
cle = W in the rule for the thickness of teeth.
Now the square root of 2100 is 45826, and supposing the wheel to be of cast-iron, then we have
= 025 W = 025 X 45826 = 1.1456 inch,
the thickness of the teeth of the wheel; consequently, if 1-10th be allowed for clearance, the pitch wil
be 1.1456 X 2.1 = 252 inches. The actual pitch would therefore be made from 21 to 21 inches.
If the wheel have wooden teeth, then the rule t = 038 W must be used, which gives 1.74 inch as
the thickness of tooth, and 3.66 inches as the pitch; the pitch to be adopted would therefore be 31
inches.
When cast-iron and wooden teeth work together, their action upon each other tends, in consequence
of the elasticity of the wood, to maintain a more uniform distribution of the strain, and being at first
commonly more accurately dressed, to prevent abrasion of the wood by the iron, they work with much
less friction, are less liable to shocks, and nearly exempt from accident by hard particles coming be-
tween the teeth.
The best practice, when a mortise and iron wheel are to work together, is to make both of the same
pitch, and in the first instance, of the same thickness of tooth-the pitch being of course calculated for
the wooden wheel by the rule p = 0785 W, which allows 1-15th for clearance, (and with good work-
manship this is amply sufficient in cases of the kind proposed afterwards to dress down the teeth of
the iron wheel, by the chipping tool, or the wheel-cutting machine, and file, to the exact form and thick-
ness, as given by the formula l = 025 W; that is, to a thickness in relation to the thickness of the
wooden teeth, which shall have the ratio of 25 to 38. Both of the wheels will then be of the same
Digitized by Google
GEERING.
803
strength, and from their superior finish, will work with much less friction, and, consequently, less wear
than if both wheels were of iron.
If m be the number of revolutions to be made by the wheel in a minute, and n the number of teeth
to be cut on it, and W the pressure upon each tooth in lbs., we shall have the following values of the
pitch p in inches and parts of an inch, agreeable to the method adopted in the preceding rules, namely,
H
For
12
3
1728
cast-iron
p
=
mn
m
H
2197
H
For
Brass
P
=
13
>
or
=
p
mn
m
n
H
2744 H
For hard wood = 14
or
=
p
mn
m
Conversely, the power which the teeth of a wheel of given pitch are capable of transmitting may be
readily calculated from the following rules, which are immediately deduced from the above:
For cast-iron
H
=
or
12'
1728
m
For brass
H
p³
=
or
13'
2197
For hard wood
H
=
or
14ª
2744
Thus supposing the pitch p = 3 inches, the number of teeth n = 60, and the number of revolutions
n which the wheel is designed to make per minute = 50; then the wheel being cast-iron, the power H
which it is capable of transmitting will be
H = 60 1728 50 = 47 horses' power nearly.
This wheel is employed to transmit 45 horses' power at the given velocity, and has been at work for
several years.
Every writer on the teeth of wheels has thought it necessary to adduce rules for finding the proper
breadth of the teeth. As respects strength, such a calculation has been shown to be in a manner un-
necessary beyond merely doubling the length, which is immediately deducible from the pitch; and as
respects durability there seems to be no theoretical limit to the breadth, for the more the pressure and
rubbing action is diffused, the less rapidly will the teeth be worn. The breadth to be assigned in prac-
tice must, therefore, be always a quantity to be determined by circumstances, and modified by the par-
ticular opinions of those concerned; if the motion be particularly uniform and free of vibration, the
breadth may be extended even to four times the pitch with advantage; but if the contrary circum-
stances obtain, this great breadth will in like manner have a contrary effect, the teeth becoming fre-
quently locked together, will more speedily wear out of shape if they be made too strong to twist and
break one another out at the ends. When the shafting is light, this is a frequent occurrence, although
the reason does not seem to be always understood; and accordingly, the remark is not uncommon, that
the wheel ought on account of its great breadth to have been more than sufficient for the work. How-
ever contradictory it may appear, strength in this sense is not an unfrequent cause of weakness and
failure.
Assuming that the teeth of wheels follow the same law of strength by increase of breadth as in thick-
ness, and referring back to the general formula for the strength of a beam of given dimensions, we
arrive at the conclusion that the breadth b and the length 1 are in the relation of b = & and suppos-
ing with some engineers of experience that a breadth of 6 inches is sufficient for a power equivalent to
9 horses, when the pitch line moves with a velocity of 8 feet per second, then we have the following
rule: Double the number of horses' power of the prime mover, and divide the result by the velocity of
the pitch circle in feet per second the result is the breadth of the teeth in inches.
Thus the power transmitted by a wheel moving at 51 feet velocity per second, transmits 16 horses'
power; the breadth of the wheel will therefore be
2 51 16 5.5 5.82 inches nearly.
Again, on the same principle, having the breadth and velocity of teeth given, multiply the velocity
of the pitch circle in feet per second by the breadth of the teeth in inches, and half the product will be
the number of horses' power which the wheel is capable of transmitting.
Thus, let the breadth be 12 inches, and the velocity 21 feet per second; then 12 X 21 = 252, half
of which is 126, the number of horses' power required.
It is easy to see, however, that unless the breadth be a function of the pitch, any calculation of this
kind cannot be satisfactory and from the remarks already made, there cannot exist such difficulty in
fixing upon the proper breadth the wheel ought to have for the particular purpose intended.
The following table may be useful in determining the relation of the dimensions of the teeth of
wheels of the given pitches, and the power which they are capable of transmitting safely at the various
speeds named. The table was originally constructed from the formula 2p"Xv 5 = H, and has since
been extensively used.
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804
GEERING.
Velocity of the wheel at the pitch circle.
Thickness
Length of
Least
Pitch.
of teeth.
teeth.
breadth of
teeth.
3 feet per
4 feet per
5 feet per
7 feet per
11 feet per
second.
second.
second.
second.
second.
Inches.
Inches.
Inches.
Inches.
H. P.
H. P.
H. P.
H. P.
H. P.
6
2.9
42
8·4
43 x
57
72
1001
158}
51
26
3.85
7.7
48
601
84to
133110
4
19
28
5.6
19
25
32
45
70
3½
16
2.45
49
143
19
24
34f
54
3
1·4
2.1
42
11
14
18
25
39
21
12
1.75
3.5
71
10
12,
171
27
2
0.95
14
2.8
4
6}
8
11
17
13
0.83
1.225
2.45
3
5
61
81/
13
1
0.71
1.05
2.1
2
31
4
6
10
1
0.59
0.875
1.75
2
2
3
4
64
1
0.53
0.7875
1.575
11
2
2
3
5
1
0.48
0.7
1.4
1
1
2
24
4
0.41
06125
1.225
1
1
13
2
34
0·36
0.525
105
7
1
1
2
0.33
0.4375
0.875
1
1
0'24
0.35
0.7
3
7
1
0.18
0.2625
0.525
3
0.12
0.175
0.35
3
To
To find the power which a wheel is capable of transmitting for other velocities than those in the
table :-For 6 feet per second, double the result given for 8 feet; for 8 feet double the result at 4 feet,
and so on; and for lower velocities than those given, divide the tabular number by the ratio which they
bear to those enumerated. Thus, for 21 feet velocity, take half the result at 5 feet, and so of other
velocities.
When a wheel and pinion, which differ very much in size, work together, the teeth of the latter, on
account of their unequal thickness, are capable of sustaining much less pressure than the teeth of the
wheel they are in effect, if not in fact, much reduced in thickness; and, in applying rules to the cal-
culation of the strength of wheels, the difference of size of the pair ought not to be overlooked, unless,
as is indeed very common in practice, the deficiency of strength be made up to the pinion by a flange
cast on one or both sides of the rim, of the same depth as the teeth, and binding these together like
the staves of a trundle. In this case the pinion is commonly the stronger wheel of the pair.
In the construction of wheels, the problem which presents itself relative to the shape of the teeth is
this, that the surfaces of mutual contact shall be so formed that the wheels shall be made to turn by
the intervention of the teeth, precisely as they would by the friction of their circumferences.
2023.
2024.
B
c
b
c
n
T
m
Thus, if we take Fig. 2023 to represent two teeth of a pair of wheels of which that marked A is the
driver; then it is plain that the faces of the teeth may be of such curvature in relation to each other,
that as the circle A revolves and carries with it the circle B by their mutual contact at C, the teeth
may continually touch one another throughout their lines of curvature, continually altering their rela-
tive positions and their point of contact t, as the primitive circles change their point of contact; and
this being true, it evidently follows that the two circles would be made to revolve by the contact of
teeth, whose surfaces are thus formed, precisely as they would by the friction of their circumferences
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GEERING.
805
at the point c. For observing the action of the circles upon each other, in the former case we find a
series of points of contact passing through c, and bringing about a corresponding rotation of points of
contact of the teeth at t; and in the latter case, the action being transferred to the teeth, the same
transposition of the points of contact at t is followed by the same transposition of points, as formely,
through c.
To form teeth whose surfaces of contact shall possess the property here assigned to the curves of
the teeth m m and nn, is the problem to be solved; and the solution is dependent on the following
Fundamental principle.-In order that two circles A and B may be made to revolve by the contact
of the surfaces of the curves m m and n n of their teeth precisely as they would by the friction of their
circumferences, it is necessary and sufficient that a line drawn from the point of contact t of the teeth
to the point of contact c of the circumferences, (pitch circles,) should in every position of the point t be
perpendicular to the surfaces of contact at that point; that is, in the language of mathematicians, that
the straight line be a normal to both the curves m m and n n.
In proceeding to establish this principle, we must in the first place recur to a proposition, which in
effect is that employed by the mechanic in the use of his templets for drawing in the curves of the
teeth. Thus if we have two circles, as in Fig. 2024, described about A and B as fixed axes, and these
circles be free to revolve by their mutual contact at T; then supposing A B the line of centres divided
as usual in T, in the inverse ratio of the angular velocities of the circles; if the circle B be provided
with a fine tracing point fixed into its circumference, and it be made to roll upon A, the point will
describe the curve b. Again, if the curve a b continued to c be cut out of thin plate and caused to
turn round the centre A, and the pin at b be carried by an arm round the centre B, the motion commu-
nicated by the pin to the curve will fulfil the required conditions. For at the beginning of the motion
let Te be the position of the curve, then the pin will coincide with T; and if the curve move into any
other position a driving the pin to b, the arc Ta will be equal to Tb, and the path described by the
pin in its motion will be that indicated by a b. But the ares T a and Tb are also those described by the
two pitch circles respectively in moving from T to the second position, and since these equal arcs are
described in the same unit of time, the angular velocity is not charged, but remains constant as if the
motion had been produced by the rolling contact of the two pitch circles.
2025.
2026.
B
b
DB
e
b
d
1
a
M
A
M
A
A further illustration of the same principle is afforded by Fig. 2025, in which A and B are centres of
motion, as before, and T the point of contact of the pitch circles of the wheels. In this case, let the
curve a c be described by a point b fixed in the circumference of a circle TbB, having for its diameter
the radius BT of the pitch circle of the wheel B. From the centre B, let a radial line Bb be drawn,
touching b and meeting the pitch circle in d. Further, let motion be communicated by contact from
the edge a b c of the curve which revolves about the centre A to the radial line Bbd, which revolves
about B, and let the beginning of the motion be reckoned from the position in which a coincides with T,
and therefore d with a; then in moving to any other position of contact, the ares simultaneously
described by the two pitch circles will be T a and Td. Now TB b is an angle at B, the circumference
of the rolling circle, and TBd an angle at the same point, which is the centre of the pitch circle; there-
fore Tb measures an angle double of Td. Also the radius Tb is half that of Td, consequently the are
Tb=Td=Ta; that is, the arcs of the pitch circles measured from the beginning of motion are equal,
and therefore the angular velocity ratio, as before, is constant and the same as would be obtained by
the rolling contact of the pitch circles.
To exhibit this principle in another point of view, let there be two circles having their axes in A and
B, and their point of contact c as shown in Fig. 2026 then supposing that the circle B is made to roll
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GEERING.
upon the circumference of A, a point in the circumference of the former will describe a curve a b; that
they are applied by their axes to a third plane MM, into which their axes are fixed, and which has
also an axis of motion coinciding with A; then it is evident if the plane M M be made to move while
the circle on A is kept at rest, the circle upon B will be made to revolve upon the circumference of this
last, and a point b fixed into its circumference will trace out a curve a b upon the plane M M, precisely
the same as would have been described by that point, if the latter plane bad remained at rest, and the
centre of the circle B had been set free from its axis, and been made to roll by its circumference on the
circumference of A. This is obvious, and it is also obvious that, both circles being fixed by their axes
to the plane M M, and the circle on A being made to revolve with an equal, but opposite angular
velocity to M M, and which communicates its angular velocity to the circles A and B, these revolving
meantime in respect to one another, and by the mutual contact of their circumferences precisely as
they would if the plane M M were at rest, then the circle A being carried round by its own proper
motion in one direction, and by the motion common to it, and the plane M M with the same angular
velocity in the opposite direction, will in point of fact rest in space; and at the same time the circle B
having no motion proper to itself, will revolve with the angular velocity of the plane M M, and all the
points of that circle will have angular velocities compounded of their proper velocities, and the veloci-
ties they receive in common with the plane M M; but these velocities being equal and opposite at the
point c, will there neutralize one another. Now this point c is the point of contact of the two circles;
so that while B revolves about A, the point c at which it is in contact with the latter is at rest; yet
this quiescent point of the circle B is continually varying its position on the circumferences of the two
circles, so that the circle B is thus made to roll on the circle A, which, in consequence of its own proper
motion in one direction being neutralized by the equal and opposite motion it receives from the plane
M M, is in reality at rest.
It therefore appears that by communicating a certain common angular velocity to both the circles A
and B about the centre A, the former is made to roll upon the latter at rest, and moreover that this
common angular velocity does not alter the form of the curve b, which a point b in the circumference
of B describes upon the plane M, that is, in effect upon the plane of the circle A; in other words, that
the curve traced under these circumstances is the same whether the circles revolve about fixed centres
by their mutual contact, or whether the centre of one circle be released and it be made to roll upon the
circumference of the other at rest. And this shown to be true, the principle announced becomes
evident; for if B roll on the circumference of A, it is evident that a point b will at any instant be de-
scribing a circle about their point of contact c, and this being true, it likewise follows that the point b
is at every instant of the revolution describing during that instant an exceedingly small circular are
about c, and therefore is bc always perpendicular to the curve a b at the point b; in other words, it is
always a normal to it.
Now returning to Fig. 2023, let P be a point exceedingly near to t in the curve n n, which is fixed
upon the circle B; it is evident from what has been shown, that as that point passes through the point
of contact t of the two curves, it will be made to describe on the plane of the circle A an exceedingly
small portion of the curve m m. But the curve which under these circumstances it describes, has been
shown to be always perpendicular to the line tc, now the curve m m being perpendicular to that line
at t, the point of contact with n n, that curve must likewise be perpendicular to it at the same instant,
and consequently we have tc; a normal to both curves at the point t. This is the characteristic prop-
crty of the two curves m m and n n by which they satisfy the condition of a continual contact with each
other at the same time that the circles revolve by the contact of their circumferences at c; and con-
versely, supposing the motion to be induced by the mutual contact of the curves, they will communi-
cate the same motion to the circles, as these would receive by the mutual contact of their circum-
ferences.
The principle here announced, exhibits a special application of one particular property of that curve
known to mathematicians as the epicycloid. The mode of generating it is that described, and that upon
which a mathematical definition of it is founded. Thus generally when two circles are in contact at
their circumferences, and the one is made to roll upon the other, any point beyond the centre in the
moving circle describes during its revolution the particular curve named. This curve, as already stated,
may be traced upon an immovable plane, against which a point in the moving circle is made to bear.
For the sake of distinctness this is termed the generating circle, and the circle upon which it rolls is
called the fundamental circle, and the portion of it on which the epicycloid rests is called the base.
The definition of the epicycloid is rendered obvious by reference to Fig. 2026, in which B is the gen-
erating circle, and A the fundamental circle of the epicycloidal curve a b. If the generating circle, in-
stead of rolling on the outside, roll within the base circle, the curve is usually called an interior epicy-
cloid; that generated when the circle rolls on the convex circumference, being termed for distinction an
exterior epicycloid.
An essential condition of the epicycloid is that the generating circle, in revolving from its first posi-
tion to different other situations, as shown in Fig. 2026, applies successively all the parts of its circum-
ference to those of the base; it is therefore evident that the base of the complete epicycloid is equal to
the circumference of the generating circle, and each portion of its base as a is equal to the corres-
ponding part c b of the generating circle by the rolling of which it is traced. Hence we have a method
of drawing the epicycloid by describing a series of circles which have all the same, diameters as the
generating circle B, and which all touch the base A then making the lengths of the arcs b taken from
the points of contact with the base equal to the ares a of the base, we can readily determine the
points of the curve, and consequently the curve itself.
The epicycloid may be described by the compasses in the following manner. Let us in the first place
take the exterior curve.
Having divided the circumference A B D, Fig. 2027, into a series of equal parts 1, 2, 3,
begin-
ning from the point A; set off in the same manner, upon the circle A x A y, the divisions 1', 2', 3',
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equal to the divisions of the circumference ABD. Then, as the circle ABD rolls upon the circle A x
A y, the points 1, 2, 3, will coincide successively with the points 1', 2', 3'; and, drawing radii from the
point 0 through the points 1', 2', 3', and also describing arcs of circles from the centre o, through the
points 1, 2, 3,
they will intersect each other successively
2027.
at the points de,
Take now the distance 1 to c, and
set it off on the same arc from the point of intersection of the
radius A C to t; in like manner, set off the distance 2 to d,
B
from b to и, and the distance 3 to e from a to v, and 80 on.
Then the points A tuv, will be so many points in the
epicycloid; and their frequency may be increased at pleas-
11
ure by shortening the divisions of the circular arcs. Thus the
A
form of the curve may be determined to any amount of accu-
racy, and completed by tracing a line through the points
found.
As the distances 1 to c,
which are near the commence-
ment of the curve, must be very short, it may, in some in-
stances, be more convenient to set off the whole distance t to
1 from c to t', and in the same way the distance b to 2 from
x
d to u³, and 80 on. In this manner the form of the curve is
0
the more likely to be accurately defined.
A second method of finding the points in the curve is, in
D
the first place, to find the positions n, of the centre of the
rolling circle corresponding to the points of contact 1', 2', 3',
&c., which may be readily done by producing the radii from
the centre O, to cut the circle EF. From these centres de-
V
scribe arcs of a circle with the radius of C A, cutting the cor-
If
responding arcs described from the centre o, and passing
1.
A
through the points t и v, as before.
Two distinct portions of the curves are represented in combination 80 as to form the faces of a tooth
of a wheel of which the primitive circumference is A x A y.
When the moving circle A BD is made to roll on the interior of the circumference A x A y, as shown
in the under part of Fig. 2027, the curve described by the point A is called an interior epicycloid. It
may be constructed in the same way as in the preceding case. The first operation is to divide the two
circles into equal parts, at the points 1, 2, 3, and 1', 2', 3', &c. Draw radii from the points 1', 2', 3',
&c., to the centre O, and also ares of circles through the points 1, 2, 3, &c., from the same centre o,
meeting the corresponding radii at the points de. Then by transferring the distances c to 2, d to 3,
to the axis A D, as in the other case, we find a series of points t u v, which may be increased in number
to any extent, and are points in the curve, through which, if a line be traced, the epicycloid will be
formed.
2028.
To determine the relation of the epicycloid and hypocycloid in
D
connection with the form of the teeth of wheels, let m p and p n, Fig.
2028, be respectively portions of these curves, having the same gener-
ating circle c Pp and having for their bases the pitch circles c D c
B
and c E c of two wheels. If the faces of the teeth upon the cir-
cumferences of these wheels coincide with these curves, it may be
m
shown that they will work truly together; for let them be in con-
c
76
tact at p, and let their common generating circle be in contact
with both pitch circles at c, then will its circumference manifestly
P
pass through the point of contact of the two teeth and if it were
made to roll through an exceedingly small angle upon the point c,
P
rolling there upon the circumferences of both circles, its generating
point would traverse exceedingly small portions of both curves.
But since a given point in the circumference of the generating cir-
cle is thus at the same instant in the perimeters of both the curves,
that point must of necessity be the point p of the curves and
since moreover the generating circle rolls upon the point of con-
tact c, its generating point traverses a small portion of the perim-
eter of each of the curves at p, it follows that the line cp is a
normal to both curves at that point; for whilst the generating
circle c P p is rolling through an exceedingly small angle upon c
E
the point p, it is describing a circle whose radius is cp. If the
teeth of a pair of wheels have their edges formed to these curves, they will therefore satisfy the condi-
tion that the line cp, drawn from the point of contact of the two pitch circles to any point of contact of
the teeth, is a normal to the surfaces of both at that point, and this condition has been shown to be
necessary and sufficient to the correct working of the teeth.
From this then it appears that if an epicycloid be described on the plane of one of the wheels with
any generating circle, and with the pitch circle of that wheel for its base; and if a hypocycloid be de-
scribed on the plane cf the other wheel with the pitch circle of that wheel as its base, and if the acting
surfaces of the teeth on the two wheels be cut 80 as to coincide with these curves, they will be driven
by the intervention of these teeth in the same manner as they would by simple contact of their pitch
circles.
It might be shown in exactly the same manner that the curves m p and n p may be generated by the
rolling of any other curve than a circle upon the pitch circles of the wheels; they would still possess
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this property, that a line drawn from any point of their contact to the point of contact of the pitch
circles is a normal to both, which, as already shown, is the one necessary and sufficient condition.
Further, it can be shown that a tooth of any form whatever being cut upon a wheel, it is possible to
find a curve which, rolling upon the pitch circle of that wheel, shall, by a certain generating point,
traverse the edge of the given tooth; and the curve thus found being made to roll on the circumference
of a second wheel, will trace out the form of tooth which will work truly with the first.
Let a Mb, Fig. 2029, be any curve whatever intended to
2029.
form the condition of the acting surfaces of teeth of the
wheel, and let c M be the pitch of the wheel; take c m =
c M, it is required to find the curve which passes through the
point m, and which being continually in contact with the
curve a M b will be impelled by the latter according to the
B
required condition. Now, as the common normal must al-
ways pass through the point c, if we draw the perpendic-
ular c t to the curve a Mb, which may be done by describ-
ing an arc of a circle from the point c as a centre, with a
a
radius such that that arc will cut the curve a M b in two
points infinitely near and joining the point c to the middle
&
c
M
of the distance of these two points, the point t will be the
point of contact of the two curves. Supposing now that
we divide the pitch c M and m into the same number of
equal parts at the points 1, 2 and 1'2', when these points
arrive successively in contact in the course of the revolution
6
of the two circles, they will coincide with the point c; and
the normal to the curve a Mb, passing through the point 1,
will also be the normal to the curve sought, and will pass
through its point of contact with a Mb. If, then, from the
point l' as a centre, with a radius equal to a normal to the
curve a M b, we describe an arc of a circle, it will be a tan-
gent to the curve sought. And doing the same with the other points of division, we find a number
of points through which, if a curve be traced tangential to the small arcs described, it will fulfil the
conditions of the problem, with more or less accuracy, according as the points taken have been more
or less numerous.
From this it therefore appears that, having the curve given of the teeth of one wheel, the curve to
which the teeth of the second wheel ought to be formed may be readily found; which is the problem
in its most general form, and may be stated summarily thus Given the form of the teeth of one wheel,
to find out the form of those of another that may work with it correctly. Solution Describe the pitch
circles of the required wheels, and find the curve which, revolving upon the one, will describe the given
tooth; make the same curve revolve within the other, and with the same describing point it will gen-
erate the tooth required.
2031.
2030.
0
B
B
o
D
D
C
e
o
a
o
A
R
It is however to be observed, that these curves, to be applicable in practice, imply the condition that
the curvature of the concavity of one tooth should be greater than the convexity of the other, or else
that both should be convex. The practical solution may be conducted in the following simple manner:
Let A and B, Fig. 2030, be two boards, whose edges are formed into arcs of the given pitch circles.
Attach to one of them the shape of the proposed tooth C, and to the other a piece of strong paper D,
the tooth being slightly raised to allow the paper to pass under it. Keep the circular edges of the
board in contact, and make them roll together. Draw upon D a number of successive positions of the
outline of the edge of C, which, touching one another in a corresponding number of points, a curve f e,
passing through these points, will be the corresponding tooth required for B. For it is obvious, from the
method it is obtained, that if the tooth be cut out, and be made to work upon C. it will touch that tooth
in every position; and therefore the contact of these curves will exactly fulfil the required condition,
by replacing the rolling action of the two pitch circles.
To illustrate the preceding process more particularly; by means of Fig. 2031, let o be the centre of
the piece B, supposed to be fixed and suppose the piece A rolling upon it over the arc c' of sufficient
extent to include the extreme positions of the acting surfaces. Then c and c', being the extreme points
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of contact of the pieces, draw the radii oc, oc', and from the centre o, with a convenient radius, draw
an arc de, meeting o c and c', produced at d and e; divide this arc into a number of equal parts, cor-
responding to the number of positions of the tooth C intended to be taken; the radii drawn to the points
of division will give corresponding points of contact at the circumference of the piece B, from which the
relative positions of the tooth C may be severally described. In Fig. 2039, the extreme positions of the
piece A and the tooth C are indicated by dot lines, though, with the exception of two other positions of
the tooth, the rest is omitted to prevent confusion. A curve nn, being traced 80 as to touch, in succes-
sion, the different positions of the tooth C, will indicate the form of tooth required for the piece B, 80 as
to geer with the piece A.
It is, however, true, that many forms of C may be tried which will prove impracticable; for some of
the successive portions of its edge may come up and interfere with parts of a b, previously drawn
thereby showing, that although it may be geometrically possible to assign a form of a b, which shall
work with any given form of C, it by no means follows that this is practically true; and, indeed, it does
not appear that any new forms of curves deduced from this general principle are likely to adapt them-
selves in practice 80 well as those commonly adopted.
There is also one curve highly applicable in practice, the importance of which requires that it be
noticed as a separate principle, which may be thus stated
The teeth of two wheels will also work truly together, if their acting surfaces coincide with curves
traced out by the extremity of a flexible line, unwinding from the circumference of a circle, and called
the involute of that circle, provided- the circles, of which the bounding curves of the teeth are respect-
ively portions, be concentric with the pitch circles of the wheels, and have their radii in the same ratio
as the pitch circles.
Thus, let there be two centres of rotation, A and B,
Fig. 2040, of which AT and BT are the primitive radii;
through the point T draw any straight line D E; through
B
the points A and B draw the perpendiculars A D and BE,
and describe circles from the points A and B as centres,
with these lines as radii. Again, let T H be the invo-
E
F
lute of a portion of the circle A D, traced by the (flexible)
line DT, and this line is manifestly a normal to that curve
K
at T; this point will also be that at which the second
2040.
curve, traced by ET, the line touches the first. But sup-
G
pose the circle A D to turn on its centre, and taking with
it the curve K T H, the line D E will be a constant normal
to that curve, in all its positions; and consequently also
to the conducting curve in all its positions, and at the
same point. Now this property of a curve, of having its
H
normal tangential to a circle, belongs only to the involute
D
of that circle; the conducted curve must therefore be the
involute of the circle BE.
As an illustration of this principle, let DE be conceived
to represent a band passing round the two circles drawn
with the radii D E and A D; the wheels will evidently be
driven by this band precisely as they would by the con-
tact of their pitch circles, since the radii of the involute
circles have the same ratio as the radii of the pitch circles.
Let it also be supposed, that the projected circles carry
round with them their planes as they revolve, and that
a tracing point is fixed at any point T of the band; it
will trace at the same instant the two curves, and upon both planes, as they revolve beneath it; it is
then obvious that these curves, being traced by the same point, must be in contact in all positions of
the circles when driven by the band, and therefore when driven by their mutual contact. The wheels
would therefore be driven by the contact of teeth of the forms of the curves thus traced by the point T
of the band, precisely as they would by the contact of their pitch circles; and it is easy to see that the
curves H TK and FTG, so described, are involutes of the circles drawn with the radii A D and B E,
from the given centres.
A particular property of teeth formed according to the principle here pointed out, is that they trans-
mit the pressure without altering its intensity-this being the same when we suppose the force con-
stantly applied at the pitch circles, but not at the points of contact of the teeth. In epicycloidal teeth
the normal to the curves is variable, as may be seen from Fig. 2029. Thus the pressure at the pitch
circles being constant, may be expressed by A c, while that upon the points of contact of the teeth will
be expressed by A t, which manifestly varies with the direction of the normal ct, and consequently
with the position of the points of contact of the teeth. Such variation does not occur when the teeth
are of the involute form; for then the relation of AD to BE, Fig. 2040, is invariable, since the constant
line D E is always normal to the curves in contact and hence it is obvious that the pressure transmit-
ted from the one circle to the other at D and E has always the same value.
An advantage of this form of teeth is, that if the distance of the centres A and B be altered, but so
that the involutes still remain in contact, the velocity of the pitch circles of the wheels will not be
affected, and therefore the angular motion of the curves in contact will remain unaltered. This is a
property which distinguishes the involute from the other curves that have been given, and is of some
practical importance; for, in a pair of wheels of which the teeth are of that form, it is not only unne-
cessary to fix the centres at a precise distance, but a derangement of the centres, from wearing of the
journals and brasses, or settlement of the framework, does not impair the action of the teeth.
102
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It may also be observed, that for every pair of pitch circles an infinite number of pairs of involutes
may be assigned that will answer the required conditions; for the inclination of ETD to the line of
centres is manifestly arbitrary, and every change of inclination mani-
2041.
festly produces a new pair of base-circles, and of involutes to these
circles.
Of epicycloidal teeth.-The simplest illustration of the action of epi-
cycloidal teeth, is when they are employed to drive a trundle, as rep-
resented in Fig. 2041. In the first place, let it be assumed, that the
staves of the trundle have no sensible thickness; that the distance of
B
their centres apart, that is, their pitch, and also their distance from the
centre of the trundle, that is, their pitch circle, are known. The pitch
l
circles of the trundle and wheel being then drawn from their respec-
K
tive centres B and A, set off the pitches upon these circumferences,
corresponding to the number of teeth in the wheel and number of
staves in the trundle; let five pins, a b c, &c., be fixed into the pitch
circle of the trundle to represent the staves, and let a series of epicy-
cloidal arcs be traced with a describing circle, equal in diameter to
the radius of the pitch circle of the trundle, and meeting in the points
k 1 m n. &c., alternately from right and left. If new motion be given to
the wheel in the direction of the arrow, then the curved face m T will
press against the pin b, and move it in the same direction; but as the
motion continues, the pin will slide upwards till it reaches m, when
the tooth and pin will quite contact. Before this happens, the next
pin a will have come into contact with the face a 1 of the next tooth,
which repeating the same action will bring the succeeding pair into
contact; and 80 on continually.
We have here assumed the pins to represent the staves of the trundle and to be without sensible
thickness, which is not true in practice. To allow, therefore, of the required thickness of staves, it is
manifestly necessary and sufficient to diminish the size of the teeth of the wheel, by a quantity equal
to the radius of the staves, sometimes increased by a certain fraction of the pitch for clearance, in this
case termed backlash. This may readily be done by drawing within the primary epicycloids at the
required distance, another series of curves parallel to these. For example, let it be required to draw
the proper tooth to impel a stave of the radius bt; with that radius plus the requisite amount of clear-
ance in the compasses, draw a series of smail ares from and within the original curve, then a curve
touching all the arcs 80 drawn will be the epicycloid required; this curve acting upon the stave will
fulfil the condition stated, for being symmetrical with the first, which passes through the axis of the
stave, it will act similarly at its circumference.
In practice, a portion must be cut from the points of the teeth, and also a space must be cut out
within the pitch circle of the driver, to allow the staves to pass; but as the sides of these parts never
come into contact with the staves, no particular form is requisite; the condition to be attended to is
simply to allow of sufficient space for the staves to pass without contact.
We have here supposed the wheel to be the driver, and this being the case it is evident that the
staves being indefinitely small, the contact of the tooth will begin at the instant its base reaches the
line of centres at a; and during the action of the tooth the point of contact will gradually slide upwards,
remaining always in the pitch circle of the trundle, at the same time it recedes from the line of centres,
until the contact is finally terminated at the point of the tooth. If the trundle be made the driver, the
pitch lines of the pair will still move with the same uniform angular velocity; but the reverse of the
preceding action will take place, for in that case the contact would commence at the top of the teeth
and cease at their base; it would moreover commence before the line of centres, and terminate when
it had reached the point of intersection of that line. Now the friction which takes place between teeth
whose point of contact is approaching the line of centres, is of a much more injurious character than that
which happens while the points of contact are receding from it. Not only does it cause much more
friction and vibration, in consequence of the inequalities of the surfaces in contact-and the surfaces
even of the most highly-polished bodies have some inequalities, which, when pressed together, interlace
-but the teeth at the same time tend to force the axes of the wheels outwards, and very speedily
induces injurious effects upon the journals, and also upon the planes of the teeth. When the action
is receding from the line of centres the friction is less intense, and its effects less injurious; it tends to
draw the axes together, and induces much less vibratory action of the geering.
For these reasons it is studied in practice to avoid as much as possible the kind of contact which
takes place before the line of centres, by making the wheel the driver and the trundle the follower.
The diameter of the staves is also commonly made equal to that of the teeth, with an allowance of a
teeth of the pitch for clearance; the radius is therefore rather less than a quarter of the pitch, conse-
quently the contact will begin, the wheel being the driver, when the centre of the stave reaches the line
of centres, and therefore at a distance before that line equal to the radius of the stave, or rather less
than a quarter of the pitch.
It is also evident that since one tooth must not quit contact before the succeeding tooth is engaged,
that when the point a has reached the line of centres the tooth T must not have quitted contact with
the stave b, and the point at which contact ceases must therefore be at an angular distance from the
line of centres equal at least to half the distance ar, that is, to half the pitch. In a pair of this kind,
the action which takes place before the line of centres is less than a half of that which takes place after
passing it.
The action of a wheel and trundle being understood, it is easy to comprehend that of the teeth of a
pair of wheels of the ordinary construction. Let A and B of Fig. 2042 be respectively the centres of a
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GEERING.
811
wheel and pinion of which the teeth are intended to be of the epicycloidal form, and A c and Bc their
primitive radii. To lay off the teeth of this pair, having determined the pitch and number of teeth in
the wheel and pinion, let the pitch lines be divided
2042.
into as many equal parts, setting out from the point
of contact c, as there are teeth in them respectively.
Let the thickness of the teeth be next set off, taking
ca for the thickness of a tooth of the wheel, and c b
for that of a tooth of the pinion. Upon the radii A c
and B c as diameters, describe two circles, having also
their point of contact at c and their centres X and Y.
Now let the circle Y be made to roll upon the pitch
line of the wheel, and a point io its circumference at
c will describe the epicycloidal arc c m, and this curve
X
determines the form of the point of the tooth of the
wheel. In the same way describe the epicycloidal are
by making the circle X to roll upon the pitch circle
of the pinion, and this curve will determine the form
of the part of the tooth of the pinion beyond the pitch
line.
Again, the teeth must have the same form on both
sides; in other words, they must be symmetrical in
reference to the radius which passes through the mid-
dle of their thickness, in order that the wheel and
pinion may be turned in either direction. If, then,
through a point equidistant from c and a and from the
centre A of the wheel, a right line be drawn as the
axis of the tooth, it limits at m the outline of the tooth
to complete the form of the addendum, it therefore
only remains to describe the opposite epicycloidal are
a m equal to m. A similar process completes the
form of the addendum of the pinion.
The curve c m of the tooth of the wheel is constant-
B
ly in contact with the radius Bc, and its point. of
contact is at the same time situated in the circumference of the circle X; the contact will therefore
cease when the extremity m of the tooth becomes the point of contact and this occurs when the point
m has arrived at the circumference of Y. If. then, an arc of a circle be described from the centre A
with the radius A m, its point f of intersection with the circumference of Y is that at which the tooth
ought to cease to act, to secure uniformity of motion, and at the same instant that another new tooth
advances into geer. The determination of the point f limits also the useful length of the flank; for if
from B as a centre, with radius Bf an arc be described, the part c 8 of the radius c B is that which is in
contact with the tooth till it arrives at the position Bf; and consequently this is the useful length of
the flank of the pinion.
Reasoning in the same manner with respect to the teeth of the wheel, it may be determined, that the
useful length of the flank of the tooth c a is the portion c g.
We have yet to find the form of the portions of the teeth within their respective pitch circles, or
more properly of the spaces between them. The first condition which presents itself is manifestly that
the spaces ought to be sufficiently large to allow the projecting portions of the teeth of the opposite
wheel to enter freely between them. To resolve this problem in its most general form, it is necessary
to find the curve described by the point m upon the movable plane of the circle of B, the pinion being
driven by the wheel A. For practical purposes this is not reckoned a matter of much importance; it
is usually considered enough that sufficient space for play be allowed whilst the tooth remains strong
enough for its work. As every tooth moves between two flanks, and touches only one of them, the
space may be bounded literally by radial lines prolonged towards the centre of the wheel. The bottom
of the space being sufficiently removed from the pitch circumference to allow the tops of the teeth of
the pinion to pass round without touching them, may be described by arcs of a circle drawn from the
centre.
By this arrangement, then, the flanks of the teeth of both wheels of the pair, that is, the portions of
the teeth which lie within the respective pitch circles, are radial lines drawn from the centres to the
pitch circles, and the faces of the teeth, or those portions which lie without the pitch circles, are arcs of
epicycloids traced in each wheel with a describing circle equal in diameter to the pitch radius of the
other wheel. Accordingly each flank and face will act in contact to produce a constant angular velocity
ratio of the pitch circles of the pair, and the action of each pair of teeth will be confined to its own side
of the line of centres.
In practice, and especially when the teeth of the wheels are small, it is not usually considered
necessary to apply strictly the form of the epicycloid to find curves of the teeth; but to define them
approximately by some such mode as the following.
Referring to Fig. 2043, after having divided the pitch circles into the proper number of parts cor-
responding to the number of teeth, and set off upon the pitch lines the thicknesses of the teeth, through
the extremity b of the pitch a b of the pinion, draw a radius B b cutting the circumference of the epicy-
cloidal circle Y in d. Joining the point d with the first division b' of the wheel, draw a perpendicular
upon the middle of the line db' meeting the circumference of A at the point h; an arc described from
this point as a centre, and with hb as a radius, will define the curve of the teeth of the wheel with
sufficient exactness.
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GEERING.
The length of the teeth is limited at d where the curve of the tooth meets the circumference of the
epicycloidal circle Y; for when the tooth has arrived at that point, another pair ought to come into
geer at the line of centres. The flank of the tooth being
radial, may be defined by a right line from the termination
2043.
A
of the curve of the face of the tooth in the pitch circle
drawn towards the centre A.
As the tooth is symmetrical about the axis A k, its op-
posite face may be described by taking off the form of the
side found upon a mould; and the two sides being thus
found, a pattern tooth may be formed and used in draw-
ing in the other teeth of the wheel.
A similar process gives the form of the teeth of the pin-
ion. Having taken an arc a e equal to the pitch, draw A e
till it meets the circumference of X in g; with this join the
division é of the pinion, and through the middle of the line
draw a perpendicular, meeting the circumference of Y in
h'; from this point as a centre, and with radius h'e', de-
scribe the curve ge', which defines the face of the tooth.
A radial line meeting the curve at e' and drawn towards
B as a centre, will in like manner define the flank of the
tooth.
To determine the bottom of the space between two
teeth, it is to be remarked that in the pinion this must be
at a distance from the centre A. at least equal to A if,
therefore, from the point B as a centre, with radius Bm, a
circle be described, it will define the bottoms of the teeth
of the pinion; and in like manner, if with radius A n a
circle be described from the centre of the wheel, it will
define the bottoms of its teeth. The angles at bottom are
commonly rounded, which, at the same time that it im-
B
proves the appearance, strengthens the teeth.
The forms of the teeth are also occasionally described by arcs, of which the radii are equal to the
pitch, and with the centres taken upon the pitch lines.
In this case the centres of these arcs must fall upon the sides of the teeth, which being already
marked off, it becomes a simple process to describe the upper portions. This method, which differs
little from the preceding, may be conveniently substituted for it, when the diameters of the wheels are
not very unequal, and the teeth not thick. But for small pinions, with larger teeth, the first method
must be adopted.
In many cases the curves of the teeth are described by arcs drawn from the centres of the adjacent
teeth upon the pitch line. This gives a radius equal to the pitch, plus half the thickness of a tooth.
In like manner, the sides of the teeth also are sometimes described by ares from the centres of the ad-
jacent teeth giving a radius equal to the pitch, minus half the thickness of a tooth.
This form of the tooth may be defective, in the case of a very small pinion having to transmit great
pressure, as the extremities of the teeth may be too much reduced. In this case, the curves or faces of
the teeth may be described with radii equal to three-fourths of the pitch; and if this be not sufficient
curvature, radii equal to some smaller fraction of the pitch may be used.
When, on the contrary, the pitch is large, and the pressure comparatively small, the teeth may be
too short; this will be remedied by employing arcs of which the radius is one and a half or twice the
pitch. A general method of determining these radii will presently be given.
Another condition which it is necessary to advert to, is the point in the circumference at which con-
tact of the teeth commences. This point is necessarily that in which the two pitch circles cut the line
of centres, as may be rendered obvious by reference to Fig. 2042. Here it is plain that the face c m of
the tooth of the wheel ought to act upon the side of the tooth of the pinion, until the extremity m of the
tooth arrives at the extremity of that side, as shown by the position of the tooth f. But were this to
take place before the acting surface of the succeeding tooth of the pinion had arrived at the line of
centres, the succeeding tooth of the wheel would of necessity act, during the first part of its contact,
upon the face of that of the pinion, and continue so to do until it had arrived at the line of centres.
On the other hand, should the extremity of the tooth on arriving at f not immediately cease contact,
but only be disengaged when the acting surface of the next tooth of the pinion had arrived at or passed
the line of centres, the face of that tooth would not be at all acted upon by the tooth of the wheel, and
the contact with the flank would be entirely beyond the line of centres. In this case, were the wheel
constantly to drive the pinion, the curved faces of the teeth of the latter might be altogether dispensed
with, without in any way injuring the equality of action. But the condition assumed does not occur in
practice; for, on account of the inequalities which take place in the motion of the wheels, whether
arising from inequality in the resistance or of speed in the moving power, the wheel and pinion act upon
each other alternately, even when the general movement is continuously in the same direction, a cir-
cumstance which cannot be safely neglected in the construction of any system of geering.
When the teeth fall into action before the line of centres, they must obviously slide upon each other
as they approach that line, and their friction, as in the case of the wheel and trundle, is then much
greater than it is after they have passed it, on account of their sliding inwards upon each other instead
of outwards, and against a pressure which is augmented in proportion to the curvature of the acting
surfaces. And, moreover, in the contact after the line of centres, although there exist inequalities on
the acting surfaces, they offer comparatively little obstruction to the sliding of the teeth upon each
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GEERING.
813
other; whereas, when the contact is in advance, every inequality becomes an abutting obstacle to the
closing in of the teeth, and which it is necessary to surmount by a species of backward motion at great
expense of motive power, and greatly to the detriment of smoothness of motion among the parts of
the geering.
But although it is thus clear that an advantage is gained by making the teeth engage after the line
of centres, yet this is as clearly desirable only within certain limits. For, as already observed, it is
necessary that the tooth of the pinion continue to geer with the wheel until the succeeding tooth has
arrived at the line of centres-a condition in which is involved the problem of the minimum number of
teeth that can be given to a pinion to work with a wheel of given size, and which may be determined
when the pitch and radii are given. From these data, the angle of the sides of the teeth is immediately
deduced. The length and thickness of teeth and width of space must be modified to answer the con-
dition imposed, and the smaller the number of teeth in the pair, the more difficulty there is in accom-
plishing the solution. To resolve the conditions of the question into the simplest form which they admit,
let us take the imaginary case of a pinion of seven teeth, without visible thickness, to geer with a wheel
of fifty epicycloidal teeth, as represented in Fig. 2044. In this the line A B is the line of centres; cm b
one of the teeth of the wheel, and B m a one of the radial teeth of the pinion, with which the tooth m b
has been in contact during its motion from c to b. Now since the pinion has seven radial teeth, the value
of the angle c B a is 3800 = 51° 25' 43"; and making the radius Bc=1, the right-angled triangle
Bm c, completed by drawing the right line c m, gives,
m = cos a B = cos 51° 25' 43" = 0-62349.
If radius Bc=1, then A c = 50 and A B = 597. Thus we have given in the triangle A m B the two
sides A B and Bm and the angle a Bc; and therefore we have also the angle B A m = 3° 35' 50".
Now if the wheel have 50 teeth, we have the angle c Ab, containing a tooth and a space, = 3600 35 =
70 12'; and subtracting from this the angle c A m, there remains the angle b A m = 8° 36' 10"; but
the angles b A m and m A c are equal, and by consequence the angle b A is double the former of those,
that is, 70 12' 20", the tooth being symmetrical in reference to Am. Now we found the angular value
of the pitch c = 70 12', which ought to contain the tooth and the space. It therefore follows that
even when the tooth of the pinion has no thickness, it is impossible to place the tooth of the wheel in
the pitch interval- for this is shown to be less than the tooth of the wheel would occupy; and it is
easy to understand that a wheel of less than 50 teeth could still less be made to drive a pinion of seven
teeth. And although in a wheel which has more than 50 teeth the pitch angle would be found greater
than the thickness of a tooth, still it would be less than that which should contain the thickness and the
space together; hence the angle which would be found due to the space would be 80 small as to be
insufficient to receive the tooth of the pinion, allowing for lateral clearance, and in consequence the pair
would necessarily geer before the line of centres.
2045.
B
m
r
2044.
B
D
m
a
S.C
b
This problem is often more conveniently solved organically, when the teeth of the wheel and pinion
are formed in the usual manner. Thus in Fig. 2045, let c B m be the angle through which it is desired
that the contact of the tooth a m should continue after passing the line of centres; then as the contact ends
at m, the point of contact will be at the extremity m of the tooth Join c m by a right line which will
be a perpendicular to the radius Br; also join A m. Then, since a was in contact with r at the line of
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814
GEERING.
centres, the are ca=cr is given, and is that portion of the pitch through which the contact of the
tooth is required to continue. Then a b is half the thickness of the tooth, minus half the base of the
portion cut off; and ea is equal to the pitch, and must contain one tooth and the space between. Sup-
posing these qualities to be equal, then since a b contains less than half a tooth, and cannot contain
more, e b must contain half a tooth and space at least, and in this case as much more as a b is less
than half a tooth. Therefore for every given value of c Bm, a value of A may be assigned which
shall make e b exactly equal to a space and half a tooth, when the tooth is pointed, and with a corre-
sponding and known increment when the tooth is blunted
If a greater radius c A' be taken, the point b will manifestly fall still nearer a and the tooth may be
still more blunted but if a less radius c A" be assumed, then the point b will fall nearer to c, and eb
will become too small to contain the space and remaining half tooth; and in this case, if the wheel
were set out, it would be found that the epicycloidal ares on the two sides of the tooth would intersect
between m and b, and therefore the tooth would be too short to continue in action through the required
arc a.
This mode of illustration is due to Professor Willis, to whom we are also indebted for the following
tables derived organically in the manner described, for spur and annular wheels:-
TABLE I.-For spur wheels, showing the least num-
TABLE 11.-For annular wheels, showing the great-
bers of teeth that will work with given pinions-Tooth
est numbers of teeth that will work with given pinions
- space.
-Tooth space.
Least number of teeth in
Greatest number of teeth in
No. of teeth in
the wheel.
No. of teeth in
annular wheel.
given pinion.
pinion.
Wheel driving.
Pinion driving.
Wheel driving.
Pinion driving.
5
impossible.
impossible.
2
impossible.
5
6
-
176
8
-
12
7
-
52
4
-
26
Arc of action c r = pitch.
8
-
35
5
-
85
9
-
27
7
14
any number
10
rack.
23
8
25
-
11
54
21
Are of action cr = pitch.
9
60
-
12
30
19
13
20
18
14
24
17
15
17
16
16
15
-
3
impossible.
impossible.
2
impossible.
10
4
-
35
3
-
77
pitch. II
5
-
19
14
pitch. - II
4
5
any number
6
-
5
12
-
7
31
12
6
77
-
8
16
10
9
12
10
10
10
10
2
impossible.
impossible
2
impossible.
14
8
I
36
4
8
pitch. can II 1 .
4
-
pitch can II
any number
15
5
64
-
5
-
13
6
20
10
7
11
9
8
8
8
These tables contain all the limiting cases under the three suppositions of the arc of action being
equal to the pitch, to three-fourths of the pitch, and to two-thirds of the same. When the are of action
and pitch are the same, the teeth of the follower may be reduced in length to the pitch circle, and the
contact of the teeth confined to their recess from the line of centres; when the are of action is reduced,
as in the other two cases given, the reduction will of course indicate the portion of contact which must
take place in advance of the line of centres. Thus when = 1 and 1 of the pitch, then it is obvious
that the contact of the teeth must begin at least t and I of the pitch respectively before they reach
the line of centres.
It also appears from the table, that a smaller pinion may be employed to drive than to follow.
Thus when the action begins at the line of centres, the least wheel that can drive я pinion of eleven
teeth is fifty-four ; but the same pinion can drive a wheel of twenty-one and upwards. Again, nothing
less than a rack can drive a pinion of ten, but this pinion can drive a wheel of twenty-three and up-
wards. No pinion of less than ten leaves can be driven, but pinions as low as six may be employed
to drive any number above those in the table. And lastly, the least pair of equal pinions that will
work together is 16. These limits being geometrically exact, and making no allowance for wear, it is
better, indeed necessary, in practice, to allow more teeth than the table assigns.
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GEERING.
815
It often occurs in practice that a wheel is required to drive more than one pinion, and vice versa,
and those of different diameters. In this case the usual mode of obtaining the epicycloidal form of
the face of the driving teeth is inapplicable, as that curve is made to depend upon the diameters of
the pair when uniformity of motion is studied. But before adverting to the methods by which this
condition may be fulfilled, it will relieve us of some of the difficulties of the question to examine the
ordinary mode in which epicycloidal teeth are set out. As the workman cannot be expected to be in
possession of that accurate mathematical knowledge which would enable him to determine the neces-
sary forms by purely theoretical means, he has recourse to the mechanical method of forming the
pattern teeth by templets. We give the process in detail.
2046.
B
A
C
Having determined the pitch of the teeth and the radius of the pitch circle by the methods de-
scribed, a thin slip of wood-say 100 thick-is provided, and on this an arc of the pitch circle is struck.
The shp is then cut to the circumference of the circular are described upon it. Another similar slip is
now provided, and on this an arc of a circle equal to the diameter of the wheel to the points of the
teeth is in like manner struck, and the edge worked off to the circumference of the circular are as be-
fore. These two pieces so prepared are laid together as in the Fig. 2046; the piece A, whose
2047.
D
g
s
s
C
edge S f is an arc of the pitch circle, is fixing upon B, whose edge is an are of the extreme circumfer-
ence of the wheel, the space 8 8 between those edges being in breadth equal to the length of the teeth
from the pitch circle to the points. The slips are held firmly in their relative position by two screws c c.
This done, a like templet is prepared for the pinion, Fig. 2047; the piece C, whose edge sg is an arc of the
pitch circle, is similarly fixed on the piece D, whose edge is an are of a circle the diameter of which is
the true diameter of the pinion, the breadth of space 88 being, as before, equal to the length of
addenda of the teeth.
2048.
2049.
m
m
c
m
D
C
O
m
O
7
to
B
U
7
D
2
A
B
The pair of templets being thus prepared, two tracing points m m are inserted obliquely, and from
behind into the piece D of the pinion templet. One of these points passes out at the edge of the
piece C, and the other at the edge of the piece D, and the templets are then placed upon each other,
as shown in Figs. 2048 and 2049 annexed, so that the circumference of the piece C, that is, the pitch
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816
GEERING.
circumference of the pinion, shall meet the circumference of the piece A, that is, the pitch circumference
of the wheel. If in this position the templets be made to roll upon each other through a certain are,
pressing them at the same time slightly together, the tracing points will mark two epicycloidal curves
upon the pieces A and B, as v and r; of these two curves, that marked v, which is traced on the face
of the piece A, will be the curve of the lower portion or flank, and that marked r will be the curve of
the upper portion, or face of a tooth of the wheel. If now the thickness of the tooth be marked off on
the edge of the piece C, that is, on the pitch circle, and the corresponding tracing point be made to
coincide with that point, the curves of the opposite side of the tooth will be formed by making the
templets roll together in the contrary direction. A complete outline of a tooth of the wheel is thus
described, to which à pattern tooth may be cut and used to shape the teeth by in making the wheel
pattern.
Let now the tracing points be taken out of the pinion templet, and inserted in exactly the same way
into the templet of the wheel, and the templets applied to each other as above shown, the operation
described will give the outline of a tooth of the pinion upon the parts C and D of the pinion templet.
Having thus found the curves of the teeth of the pair, pat-
2050.
tern teeth may be made and used in setting them out; but
this mode is not uniformly adopted. Instead of forming
pattern teeth, many prefer to lay off the teeth by circular
B
c
D
ares coinciding approximately with the epicycloidal arcs
found by the templets. This is readily done by taking any
three points in the curve, and finding the radius with which
a circle may be drawn whose circumference will pass through
F
G
H
the points 80 taken, and which will thus of necessity coincide
approximately with the normal curve. Radii being found
for the curves of the top and bottom of the teeth of the wheel
and pinion, their centres are transferred to the circumference of the pitch circles, and circles drawn
within these last. Figs. 2050 and 2051 illustrate the process. The ares B and D, drawn with the
radii A B and CD, are those of the face and flank of the wheel tooth; and the arcs F and H, drawn
with the radii EF and G H, those of the corresponding off teeth, are drawn from the pitch circles cc,
Fig. 2051, and parts of the tooth. The pinion curves of the faces in setting those of the flank are drawn
from the circles nn within the others.
2051.
n
The preceding is a very common mode of obtaining the curves of the teeth of a pair of wheels which
are to geer together; but it is faulty, in as far as it gives a form of teeth smaller at the root than at the
pitch circles, and also in the circumstance that a pair of wheels set off with templets formed in the
manner described, will only work correctly with each other, and not with wheels of any other numbers,
although of the same pitch. Thus, a wheel of 30, set off as described, to work with another of 50, will
not work correctly with a wheel of 40 or of 60, although the pitch be the same. To effect this it is
necessary to employ the proposition already announced and illustrated, and which shows that if there
be two pitch circles touching each other, then an epicycloidal tooth formed by causing a given describing
circle to roll on the exterior circumference of the one, will work correctly with an interior epicycloid
formed by causing the same generating circle to roll on the interior circumference of the other. This
proposition having been already established, it is unnecessary to dwell upon it further than to observe,
that although it has been admitted into the workshop as a fundamental truth, the practice founded upon
it does not afford the full advantage which it is adapted to afford, and which might be derived from it
by a slight modification of the ordinary practice.
To describe the practical application of the principle, let a thin slip of wood be provided, and let an
arc of the pitch circle be struck upon it; divide the slip into two portions through the line of this are
with a fine saw one part, A, will have a concave, and the other, B, a corresponding convex circular edge.
(Or the same slip may be made with a convex and concave edge of the same radius.) Describe an arc
dd of the pitch circle upon a second board CD, upon which the pattern tooth is to be drawn. Fix the
piece B upon the board, so that its circular edge may accurately coincide with the circumference of the
are dd. A portion of a circular plate D is next provided, of the same radius which it is proposed to give
to the generating circle: this plate has a fine tracing point at P inserted into it, and projecting slightly
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GEERING.
817
from its under surface, and accurately coinciding with its circumference. Having set off the thickness of
the tooth a c upon the pitch circle dd, so that twice this width increased by the clearance which it is
desired the teeth should have, may be equal to
the pitch, the generating circle D is made to roll
upon the convex edge of B; meantime the point
at p will trace upon the board the curve of the fa-
ces of the tooth, having caused the point to coin-
cide successively with the two points a and c, and
the circle to roll from right to left, and vice versa.
Let the piece B be now removed, and the
2052.
piece A applied and fixed, so that its concave
edge may accurately coincide with the circular
arc dd; then, with the same circular plate D
pressed against the concave edge of A, and
D
made to roll upon it, the point at p, which is
made as before to coincide successively with the
c
D
points a and c, will trace upon the surface of the
board CD the two hypocycloidal arcs a b, b,
e
which form the flanks of the tooth. The com-
a
plete tooth, thus formed, has this advantage
over the form of tooth found by the former
b
B
mode, that it will work correctly with the teeth
similarly described upon any other wheel, pro-
vided the pitch of the teeth be the same, and
provided the same generating circle D be used
to strike the curves upon the two wheels.
In this manner the general forms of the teeth of the pair are determined. And it only remains to
cut them off at such lengths that they shall come into contact in the act of passing through the line of
centres. Thus, in Fig. 2042, let Y be the centre of the generating circle of the teeth, then the points
ab, where the circle intersects the edges of the driving teeth, are the points of contact of the teeth
Now as the teeth ought to come into action only at the line of centres, it is clear that the tooth f must
have been driven by the tooth of the wheel from the time their contact was at c, to which another
tooth of the wheel is shown to have advanced, the former being about to quit contact; and since the
tooth now advanced to c is about to take up the task of impelling the driven wheel, and the other to
yield it, it is clear that all the part of the tooth falling within the circumference of the generating circle
might be removed; this done, it is evident that all the driving strain would immediately be transferred
to the succeeding pair of teeth as required. In order, therefore, to obtain a form of tooth which shall
satisfy this condition, by the mode of setting out which has just been described, it is only necessary to
take ac, in Fig. 2052, equal to the pitch of the tooth, and to bring the circumference of the generating
circle D to touch the convex circumference of the are dd in that point: the point of intersection o of
this circle, with the face ta, will be the last acting part of the tooth; and if a circle passing through
that point be struck from the centre of the pitch circle, all that portion of the faces of the teeth which
lie beyond it may be cut off. The length of the tooth of the wheel intended to act with this may be
determined in exactly the same manner. It may, however, happen that the point o will fall beyond
the point t of the tooth; when this occurs, it is then impossible to cut the teeth of such length as to
satisfy the condition that they shall drive only after the line of centres. This may be proved organi-
cally with a pair of 15 to 15, and other numbers which the preceding table of cases will suggest.
We have here supposed the same generating circle to be used in striking the entire surfaces of the
teeth of both wheels. This is convenient, but not essentially necessary; for if the same generating
circle be used in striking those parts of the teeth which act together, the required condition will be
satisfied. Thus the flank of the driving tooth and the face of the driven tooth come into actual contact;
it is therefore requisite that these curves be respectively an epicycloid and hypocycloid, struck with the
same generating circle. And, again, the face of the driving tooth and the flank of the driven tooth being
in contact, these curves must in like manner be struck with the same generating circle. But it is evi;
dently unnecessary that the same generating circle be used in the first and second cases any generating
circle will satisfy the proposed conditions in either case, provided it be the same for the epicycloid and
the hypocycloid, which are to act together; observing, however, that as the diameter of the generating
circle is increased, the thickness of the root of the teeth will be diminished and conversely, when
made less than the radius of the pitch circle, the root of the teeth will spread out, and the curvature of
the epicycloidal faces will be proportionally increased, and the teeth shortened. From these observa-
tions it is also clear that the forms of the teeth of a
pair of wheels which are required to drive continuously in
2053.
one direction may be 80 modified as to give additional
strength to the teeth without impairing their delicacy of ac-
tion. Thus, if the wheels represented here, Fig. 2053, the
lower A B being the driver, move always in the direction of
the arrows, then, instead of the teeth being formed symmet-
rically, the back of each tooth may be filled up, either by
striking the curves by a very small generating circle, or bet-
ter by involutes, which being proportional to the pitch circles
B
will be sure to clear during the working of the wheels. By
this means the strength of the teeth is greatly augmented,
as must be obvious, and their action is in no way impaired, since the acting surfaces are not altered
103
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818
GEERING.
Returning now to the condition often required, though seldom fulfilled in practice, of making wheels
of different numbers, when of the same pitch, to work correctly together, it is clear from what has been
advanced in connection with the preceding mode of setting out, that it is not absolutely necessary to
assume the generating circle of any precise radius; it may be taken greater or less within certain limits
without affecting the correctness of the working surfaces of the teeth.
Proposition.-" If for a set of wheels of the same pitch, a constant describing circle be taken and
employed to trace those portions of the teeth which project beyond each pitch line by rolling on the
exterior circumference, and those which lie within by rolling on the interior circumference; then any
two wheels of this set will work correctly together."
In illustration of this principle, first announced by Professor Willis, he adduces the established and
well-known condition, that the portion of each tooth within the pitch line of a driving-wheel works only
with the portion which lies beyond the pitch line of the follower, as above shown, and that its action is
confined to the approach of the point of contact to the line of centres. After the point of contact of the
teeth has passed that line, then the case is reversed, and the portion of the driving tooth which lies
beyond the pitch line is in contact only with some part of the follower's tooth, which lies within its pitch
line. Consequently, if a constant describing circle be used for the whole set, it is clear that the propo-
sition will apply to any pair of the wheels, both before and after the teeth have passed the line of
centres; for in each case we have an exterior epicycloid working with an interior epicycloid, and both
have been drawn by the same describing circle; that is, by the constant circle of the set.
To carry this scheme into practice, it only remains to settle the proper diameter to be given to the describ-
ing circle. Let the external circle B C, Fig. 2054, be a pitch circle whose centre is 0; then upon this system
the flank of the tooth-that is, the portion of it which
2054.
lies within the circle-will be an arc of an interior
epicycloid (or hypocycloid) mn or m' n. Now, if the
describing circle be half the diameter of the pitch cir-
cle, the flank will become a straight line, coinciding
with the radius o n, as shown in Figs. 2042 and 2043.
But if the describing circle be of less than half the
diameter of the pitch circle, the flank m n will be con-
cave, and the base of the tooth will spread on the
contrary, if the describing circle be more than half the
C
o
B
diameter, the flank m' n will be convex, and the base
of the tooth will be contracted inwards-a form man-
ifestly unpractical and useless. It is therefore clear,
that the describing circle must not be greater than
half the diameter of the pitch line; nor must it be too
small, for then the base of the teeth would spread
inconveniently, and the curvature of the exterior epi-
cycloids would be injuriously increased, and the teeth
m
$
become too short. The circle selected should there-
fore be as large as it can, consistently with the limita-
76
tion just stated, 80 that we finally arrive at the prac-
tical rule: Make it equal in diameter to the radius of
the least pitch circle of the set. And, as pinions should never have less than 12, and if possible not less
than 14 teeth, it would be well to establish one of these numbers for that least pitch circle.
Thus, then, by the use of the same generating circle for all the wheels of the same pitch, they will
all work correctly together.
It has already been observed, that, having found the epicycloidal curves of the teeth, by means of the
templets, a common method of proceeding is to find, by trial, a centre and small radius, by which the
arc of a circle can be described that will coincide nearly with the templet-traced curve. Having found
these, as in Fig. 2052, and having struck upon the ends of the rough cogs of his pattern, a circle, con-
centric with the pitch circle, and whose distance from it is equal to that of the centre of this arc, the
workman adjusts his compasses to the small radius, and always keeping one point in the circle just
described, he steps with the other to each cog in succession, the cogs having been previously divided
into two parts corresponding to the pitch and thickness of the teeth. Upon each cog he describes two
arcs, one to the right and the other to the left, which serve him as guides in shaping and finishing the
acting surfaces of the teeth. The practical convenience of this method is evinced by the extent of its
adoption, and requires only to be aided by a more commodious and certain method of determining the
centre and radius of the approximate arc, which has been supplied by Prof. Willis.
But before entering upon the geometrical consideration of the conditions involved, it may simplify
the investigation to explain, in the first place, the practical application which Mr. Willis has made of it
in the construction of his Odontagraph, an instrument which deserves to be extensively known and un-
derstood. The fundamental principle which it involves may be thus exhibited:-
Let A, Fig. 2055, be the centre and AT the radius of the pitch circle of a proposed wheel draw T 3,
making an angle A T3 = 75° 30', with the radius, and drop a perpendicular A 3 upon T3.' Or draw
AT, and upon it describe a semicircle, and cut off T3 = & of AT, that is, equal to a quarter of the
radius, then will 3 be the centre from which, if an arc p be described through T, that arc will be the
side of the tooth required.
This principle being established, it may be adapted conveniently to practice by constructing a bevel
of brass, of the requisite form, the angle at T being 751 degrees the side T3 may for convenience be
graduated into a scale of quarters of inches as in the Figure; and these divisions may be further sub-
divided if thought proper. If the bevel so formed be laid upon the radius A T of the proposed wheel
and its point T to the pitch circle, the centre point 3 will be found at once by reading off the length of
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GEERING.
819
the radius of the wheel in inches upon the reduced scale. Thus in the figure the radius A T is three
inches long, and the point 3 is found at 8 of the scale.
To draw the curves of the other teeth, describe from centre A with radius A 3 the circle pq, dotted
in Fig. 2055, and falling within the pitch circle; this will be the locus of the centres of the teeth. Thus
having divided the pitch circle into arcs corresponding to the pitch of the teeth, take the constant radius
3T in the compasses, and keeping one point in the dotted circle as at q, step from tooth to tooth, de-
scribing successively the arcs of the faces first to the right and then to the left. For example, m n is
described from centre q, and P 0 from P.
9055.
6
$
B
1
0
P
T
m
11/16
C
The sides of teeth thus formed, consisting each of a single arc, bear considerable analogy to involute
teeth, and like these have the fault of acting together with rather too much obliquity; but the mode of
describing them is exceedingly simple, and they have this advantage, that they will work correctly with
wheels of any number of teeth, with any amount of clearance, and without any great nicety of adjust-
ment of the pitch circles. For wheels of a small pitch-as 1 inch and under-this mode of setting out
may be adopted without risk; but when the sides of the teeth consist of single arcs, there can only be
one position of action in which the angular velocity will be strictly constant-and that is when the
point of contact is on the line of centres. This objection is obviated by making the side of each tooth
to consist of two arcs, joined at the pitch line, and so struck that the point of action of the one shall be a
little before the line of centres-say at the distance of half the pitch; and the exact point of the other
at the same distance beyond that line.
The mode of drawing these arcs is very fully described by Professor Willis, but it is much too com-
plex to be rendered available in the workshop; besides, it has been rendered superfluous for practical
purposes by his Odontagraph, in which it is embodied. This instrument, which is fast coming into use,
is usually formed of card-paper, sheet-brass, or plane-tree. Fig. 2056, as constructed by Messrs. Holt-
zapffel and Co., of London, contains within it the requisite tables of numbers.
One side is graduated into a scale of half inches, each half inch being again subdivided into ten equal
parts. The line tD, which corresponds to the radius of the wheel, makes an angle of 75° with the side.
The mode of using the instrument is thus explained in its application to the setting out of a wheel of
29 teeth of 3-inch pitch.
Describe an arc of the required pitch circle, and upon it set off the pitch Tt, Fig. 2057; bisect this
in e, and draw radial lines BT and Bt. For the arc within the pitch circle apply the slant edge of the
scale to the radial line Bt, placing its extremity t on the pitch circle as in the Fig. In the table
headed Centres for the Flanks of the Teeth, look down the column of 3-inch pitch, and opposite to 80
teeth-which is the nearest number to that required-will be found the number 49. The point T indi-
cated on the drawing board by the position of this number on the scale of parts marked Scale of
centres of Teeth within the Pitch Circle," is the centre required, from which the arc of must be drawn
with a radius re.
The centre for the are de, which lies outside the pitch, is found in a manner precisely similar, by
applying the slant edge of the scale to the radial line BT. The number 21 obtained from the table of
Centres for the Faces of the Teeth, will indicate the position of this centre upon the scale of Centres for
Teeth outside the Pitch Circle, namely, at R.
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820
GEERING.
2056.
THE ODONTAGRAPH.
210
900
TABLE SHOWING THE PLACE OF THE CENTRES
190
UPON THE SCALE.
180
CENTRES FOR THE FLANKS OF THE TEETH.
170
160
PITCH IN INCEES AND PARTS.
150
Num-
ber of
t
1
1
coton
t
1
11
If
14
2
21
8
Scale of centres for the fianks of the teeth.
21
st
140
teeth.
130
13
32
48
64
80
96
129
160
193
225
257
289
321 386
450
14
17
26
35
43
52
69
87
104
121
139
156
173
208
242
120
15
12
18
25
31
37
49
62
74
86
99 111.123 148
173
16
10
15
20
25
30
40
50
59
69
79
89
99
191
138
110
17
8
13
17
21
25
34
42
50
59
67
75
84
101
117
100
18
7
11
15
19
22
30
37
45
52
59
67
74
89
104
19
10
13
17
20
27
35
40
47
54
60
67
80
94
90
20
6
9
12
16
19
25
31
37
43
49
56
62
74
86
22
5
8
11
14
16
22
27
33
39
43
49
54
65
76
80
94
7
10
12
15
20
25
30
35
40
45
49
59
69
70
26
9
11
14
18
23
97
32
37
41
46
55
64
28
4
6
13
22
26
30
35
40
43
52
60
60
30
8
10
12
17
21
25
29
33
37
41
49
58
35
:
9
11
16
19
23
26
30
34
38
45
53
50
40
5
7
:
:.
15
18
21
25
28
32
35
42
49
40
60
3
6
8
9
13
15
19
22
25
28
31
37
43
30
80
4
7
12
17
20
23
26
29
35
41
100
..
8
11
14
:
:
22
25
28
34
39
90
150
5
:.
13
16
19
21
24
27
32
38
Rack.
2
:
:.
6
7
10
18
15
17
20
22
25
30
34
10
t
Θ
Scale of centres for the
10
faces of the teeth.
20
30
40
D
TABLE SHOWING THE PLACE OF THE CENTRES UPON THE SCALE.
CENTRES FOR THE FACES OF THE TEETH.
PITCH IN INCHES AND PARTS.
Number
t
1
t
1
t
1
11
11
11
2
21
21
8
st
of teeth.
12
1
2
2
3
4
5
6
7
9
10
11
12
15
17
15
8
7
8
10
11
12
14
17
19
20
2
4
5
6
8
9
11
12
14
15
18
21
30
3
4
7
9
10
12
14
16
18
21
25
40
6
8
...
11
13
15
17
19
23
26
60
5
10
12
14
16
18
20
25
29
80
9
11
13
15
17
19
21
26
80
100
7
18
20
22
31
150
5
6
...
...
14
16
19
21
23
27
32
Rack.
4
10
12
15
17
20
22
25
30
34
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GEERING.
821
The double curve df is also true for an annular wheel of the same number of teeth, f becoming of
course the point of the tooth and d its root. For a rack the pitch line Tt will be a straight line, and
Bt, BT, drawn perpendicular to it at a distance from each other, equal to the pitch
2057.
E
200
150
100
50
r
D
B
T
R
a
The numbers for pitches not stated in the table, may be obtained from the column of some other
pitch by direct proportion. Thus for 4-inch pitch, by doubling the number of the column of the 2-inch
pitch; for 41 by doubling 21, and 80 on; or if the difference be small, the column belonging to the
2058.
nearest pitch may be employed without a serious error; or more accurately, a number may be taken
half-way between those given in the two nearest columns. Also no tabular numbers are given for 12
teeth in the upper table, because within the pitch circle their teeth are radial lines.
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822
GEERING.
In reference to the numbers given in the tables, the inventor observes that it is unnecessary to extend
these to every wheel, as the error produced by taking those belonging to the nearest, as above directed,
is so small as to be unappreciable in practice.
The difference in form between the tooth of one wheel and of another is due to two causes; the first
is the difference of curvature, which is provided for in the Odontagraph, by placing the compasses at
the different points of the scale of equal parts; and secondly, the form depends on the variation of the
angle T Bt, Fig. 2057, which is met by placing the instrument upon the two radii in succession.
The first is the only cause with which these calculations are concerned. Now in three-inch pitch, the
greatest difference of form produced by mere curvature in the portion of tooth which lies beyond the
pitch circle, is only 1-25th of an inch between the extreme cases of a pinion of 12 teeth and of a rack;
and in the acting part of the arc within the pitch circle it is 1-10th of an inch; so that as all the other
forms lie between those two, it is clear that if we select only four or five examples for the outer side of
the tooth, and ten or twelve for the inner side, we can never incur a greater error than the 200 part of
an inch, in a three-inch pitch, by always taking the nearest number in the manner directed, and a pro-
portionally smaller error in smaller pitches. But to insure this, the numbers ought to be 80 taken, that
the corresponding form shall lie equally between the extremes. This is more necessary with wheels of
small numbers of teeth, since the variation of form is much greater among the teeth of low than among
those of larger number.
Fig. 2058 shows the relation of the curves of the teeth of a rack and pinion of 12 teeth, both adapted
to work into the same wheel. They are drawn with accuracy, and on a large scale, 80 as to afford a
graphical comparison of the two extreme cases.
The Odontagraph is likewise applied to determine the correct form for cutters used in the wheel-
cutting machine, for shaping the teeth of metal and cog wheels. The form of the cutter is manifestly
that of the space between two contiguous teeth; and may therefore be determined by drawing a pair
of teeth in any particular case. But in making a set of cutters especially for small pitches, it is not by
any means necessary to make one for every number. The forms for numbers of teeth that lie closely
together are, as already remarked, very nearly alike-so nearly alike indeed, that the errors of work-
manship would entirely destroy the difference, particularly when the numbers are high. When the num-
bers are very low, there is less room for deviation from the strict rule-not more, for example, between
the form of a cutter for 16 and 17, than there is for a cutter for a wheel of 150 teeth and another for
one of 300. This being the case, it appeared to Mr. Willis to be worth while to investigate some rule
by which the necessary cutters could be determined for a set of wheels, 80 as to incur the least chance
of error; and to this effect he has calculated, by a method sufficiently accurate for the purpose, the
following series of what may be termed equidistant values of cutters; that is, a table of cutters 80
arranged that the same difference of form exists between any two consecutive numbers.
TABLE OF EQUIDISTANT VALUES FOR CUTTERS.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
No. of
Rack.
300
150
100
76
60
50
43
38
34
30
27
25
23
21
20
19
17
16
x
15
14
13
x
12
teeth.
This table affords the requisite information in the selection of the wheel to which each cutter shall be
accurately adapted, after it has been determined how many are necessary in a set. For example, if a
single cutter were thought sufficient for a set of very small wheels, it had better be accurately adapted
to teeth of 25, for that value is intermediate between the two extremes. If three cutters are to suffice
for the whole set, then 76, 25, and 15 ought to be selected-of which the cutter 76 may be used for all
teeth from a rack to 38; the cutter 25 from 38 to 19, and the cutter 15 from 19 to 12; and so on. In
cutters, the greatest difference of form is at the apex of the tooth, that is, at the base of the cutter, and
this amounts to t of an inch in 2-inch pitch, when the teeth have the usual addendum. From this the
difference for any smaller pitch may be ascertained, and as many cutters interposed as the workman's
notion of his own powers of accuracy may induce him to think necessary. Thus, if the hundredth of an
inch be his limit of accuracy in forming his cutters, and he proposes to make a set for half-inch pitch,
where the difference of form is & X t = 18, that is, Too nearly, then half a dozen cutters will be
sufficient, and these must be made as nearly as possible to suit the wheels 150, 50, 30, 21, 16, 13.
The following table contains a selection of numbers for different cases which may save trouble :-
TABLE OF CUTTERS.
No. of cutters
in the set.
Numbers of Teeth to be selected.
2
50
16
3
75
25
15
4
100
34
20
14
6
150
50
30
21
16
13
8
200
67
40
29
22
18
15
13
10
200
77
50
35
27
22
19
16
14
13
12
300
100
60
43
34
27
23
20
17
15
14
13
18
300
150
100
70
50
40
30
26
24
22
20
18
16
15
14
13
12
24
rack
300
150
100
76
60
50
43
38
34
30
27
25
23
21
20
19
18
17
16
15
14
13
12
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GEERING.
823
When the numbers have been selected, the Odontagraph may be employed to draw the figure of the
cutter corresponding to each wheel, either on the same scale, or better, on a larger scale, which may be
afterwards reduced proportionally to the size required.
To explain the principle of the Odontagraph, let us, in the first place, observe the action of the two
pieces in the annexed diagram, Fig. 2059, of which P and Q are the centres of curvature at the points
9059.
0
B
P
M
M
8
n
P
of contact, and which are capable of revolving round A and B. It is plain that the line PQ is, in every
position of contact of these curves, equal to the sum of their radii, and must therefore be constant during
such motion; and hence, if for the circular arcs, a pair of rods AP, BQ, connected by a link PQ, be
substituted, their angular velocity will be to each other as the segmental arcs which they respectively
represent, and PQ will be a constant and common normal to their arcs of motion. It is also clear that
a change in the actual lengths of the radii will not affect the motion, the distances of the centres being
constant. Now let the rod A P be moved into a new position Ap, as shown in Fig. 2060; its extremity
2060.
R
If
L
T
B
Q
I
will manifestly carry with it the end of the link PQ, and communicate through it a motion to the arm
BQ, causing it to assume likewise a new position Bq. It is necessary to know the relative value of
this motion to that of AP which produced it, which, though constantly changing, may be thus deter-
mined at any instant.
When the rod PQ changes its position, it may be considered during its motion to turn about some
centre in space, although the relative position of that centre be perpetually shifting. This centre must
of necessity be the point in which the arms A P, BQ would intersect if produced: Thus the momen-
tary centre, when the motion begins, is K. For as the extremity P moves round the centre A, the
direction of its motion at starting must be perpendicular to AP, and therefore the momentary centre
must be somewhere in the line AP produced. In like manner the initial motion of the extremity Q
must be perpendicular to BQ, and the momentary centre must lie somewhere in the direction BQ Q:
but these directions intersect in K, which is therefore the centre in space about which the rod PQ on
starting into motion may be conceived to turn. And since the rod PQ turns about K, the direction of
motion of P and Q are to each other at any given instant as their radial distances from K; that is, as
PK and QK, which is true whether we consider them as the extremities of the rod PQ or of the radii
A P, B Q; also the angular motions of the latter will be found by dividing those direct motions by their
radii; that is,
Angular motion of
PK QK
P round A: angular motion of Q round B :
AP : BQ
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824
GEERING.
If now we draw BS, then we have
KL: AR by similar triangles KPL; APR
BQ: QK KL
BQS KLQ
......
ART BTS
And compounding these three proportions we obtain
PK QK
BQ
that is to say, the angular motion of the arms are to each at any moment inversely as the segments into
which the link divides the line AB, joining the centres of motion or line of centres. If now the link
move into a new position pq near the first, and it happen that this second position intersects the first
in a point L above or below the line of centres, as shown in the Figure, then the ratio AT: BT will
be changed into At: Bt, and consequently the angular motion will be an increasing or decreasing ratio.
But if the point L coincide with the line of centres, this ratio for the moment will remain constant.
Now, a little consideration will show that the point of intersection between two successive positions
PQ, pq of the link must be at the place where the perpendicular from K falls upon it. For as K is
the momentary centre of motion, the extremity L of the perpendicular will begin to move in line at
right angles with it, and consequently will remain in the direction of the first position when the link has
passed into the second position; in other words, it will be in the point of intersection of the two posi-
tions. When, therefore, the rods are in such a position that the perpendicular from K meets the link
PQ in the line of centres, the ratio of the angular motions of A P and BQ is constant; and if in this
state the points P and Q be employed as centres whence short arcs are drawn through any common
point M', as in Fig. 2059, and applied as teeth, these arcs will manifestly drive each other correctly
when in the exact relative position described, and very nearly so when removed to a short distance on
either side of it, which is the thing required.
2061.
Now these relative positions of P and Q may be determined by a
simple construction founded upon the necessary coincidence of L and
T. Thus let A and B, Fig. 2061, be the centres of a pair of wheels,
and A B the line of centres divided at T, the point of contact of the
B
pitch circles. Draw PTQ, making any angle with the line of centres,
and upon it assume P as a centre from whence the circular side is to
S
be described of a tooth of the wheel whose centre of motion is A. To
find the corresponding centre for a tooth of the wheel which turns upon
B, draw TK perpendicular to PQ, produce AP to meet it in K; join
KB and produce it to meet in Q, then will Q be the required
centre-as will appear by comparing Fig. 2061 with Fig. 2060. If
then a small arc m n struck from P be taken as the face of a tooth of the wheel on A, it will work cor-
rectly with an arc m p struck from Q through m, and employed as a tooth of the wheel on B.
Were BQ 80 taken as to make the angle K BT acute-for example at B', then would Q fall at Q'
on the same side of T as P, but beyond it, and the effect would be that the tooth m p would be concave
instead of convex. And if the angle = then will K B become parallel to PT, and the
point Q being thus removed to an infinite distance, the arc m P of the tooth of the wheel on B will be
a right line perpendicular to PT.
The angle ATP is arbitrary, and its value may, therefore, be determined from other conditions than
those stated. It may be remarked, however, that if made a right angle, the points P and Q will vanish
by coinciding with T; and if it be made a little less than a right angle, the points P and Q will be
thrown 80 near to T, that the radii by which the arcs are struck become too short, and the points of the
teeth too much rounded off. On the other hand, if the angle A TP be made too acute, the action of the
teeth upon each other at the moment of passing the line of centres and elsewhere becomes very oblique,
and an injurious pressure is thereby thrown upon the axis of the wheels. By various trials Mr. Willis
has adopted 75° as the value of the angle which appears to avoid these extremes, and he has accord-
ingly employed it in the construction of his Odontagraph.
Again, the position of the point m, through which the arcs are to be struck, is also arbitrary, and
must be determined by considering which point of the action we wish to make the correct point. If
the teeth consist of a single arc each, the correct point may be fixed at the moment of passing the line
of centres, and therefore the arcs must be struck through the point T; but if the side of the tooth be
formed of two arcs joined, one lying within and the other beyond the pitch line, then the action of one
of them will be confined to the approach of the point of contact of the teeth and the line of centres, and
the action of the other to its recess from that line, and m must be assumed upon such a principle that
the correct point of each arc shall fall nearly in the middle of its action.
The distance between the centres may also be found by calculation, thus: AR being perpendicular
to PT, we have by the similar triangles ARP; PTK
PTXAR
PR
TR-PT
sin ATP
AT.co& ATP-PT
therefore sin
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which is the centre for the arc m n. And similarly drawing BS perpendicular to TQ we have for the
corresponding arc m p.
Now the point P being obtained from the point K on the opposite point of T to A, these formulae be-
long to that part of the tooth of the lower wheel beyond the pitch line and the flank of the tooth of the
upper wheel The corresponding face of the upper and flank of the lower wheel may be determined
in a similar manner, by joining Bk and following the course of reasoning stated for the point K.
In these formulse, the values of PT and QT may be determined for any forms of teeth, and also for
a set of wheels which shall work correctly together. But the greatest value which in this last case can
be correctly assigned to KT must be one which, if r be the smallest radius, shall make
KT=reinATP
Consequently, putting R for the radius of the wheel, and angle ATP = 0 the values of D and d, that
is, the distances of the centre points of the ares measured from T, will become
d-R.r.come
By assuming constant values of r and Θ in a set of wheels, the values of D and d which correspond
to different numbers and pitches may be calculated and arranged in tables for use. In this way the
tables which accompany the diagram of the Odontagraph were obtained by taking the least number
of teeth to be given to a wheel = 12 and = 75°, the numbers being expressed in twentieths of an inch.
In this way these tables may be extended at pleasure, and for any values of r and Θ; and perhaps it
would be preferable in the construction of such tables to express the numbers in inches and 32ds of an
inch, which would better adapt them to the common foot-rule.
Involute teeth.-Involute teeth have the disadvantage, already stated, of being, when in contact, too
much inclined to the radius, by which an undue pressure is transferred to their axes. Their mutual
friction is thereby little affected, but that of the axes is increased, and their journals are more speedily
worn. But they have at the same time the advantage of working with more accuracy under derange-
ment and incorrectness of fitting, and any pairs of them will work truly to-
gether in sets within certain limits, however different in diameters, the pitch
2062.
being the same. Until Professor Willis had developed the mode of adapting
the epicycloid to the condition in question, the involute was the only form
known in practice by which the conditions of perfect figure for wheels of any
sizes to work smoothly in wheels of any other sizes, could be satisfied.
B
To describe this curve for the teeth of a pair, of which the radii of the pitch
circles, and pitch of the teeth are determined, we may employ the mode
illustrated by Fig. 2062. Let A and B be the centres of the pair, and eb be
their pitch lines; join A and B by a right line passing through c; from this
last point draw cd, c d perpendicular to the radials Bd, Ad, and cutting them
in d and d; this line dd is then a common normal to the teeth in contact, and
the perpendiculars A d, B d, are the radii of the involute circles which form
the acting faces of the teeth.
The involute curve may be described mechanically in several ways. Thus
let A, Fig. 2063, be the centre of a wheel, for which the form of involute teeth is
A
to be found. Let m.n a be a thread lapped round its circumference, having a
loop-hole at its extremity a; in this fix a pin, with which describe the curve or involute a b h, by
unwinding the thread gradually from the circumference, and this curve will be the proper form for the
teeth of a wheel of the given diameter.
9064.
B
b
o
9063.
2065.
TM
d
B
The involute a b---h may also be produced by an epicycloidal motion; for since the circumference
of a generating circle, whose centre is infinitely distant, must be & straight line, we may form the invo-
104
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lute by making a straight ruler roll upon the circumference of the circle to be evolved. Thus let R, in
Fig. 2063, be a straight ruler, at whose extremity a pin P is fixed with the point resting upon the point
q of the circle; then by rolling the straight ruler upon the circumference, so that the point at which it
touches the circle may move gradually from q towards r, the curve q p will be generated exactly simi-
lar
to
the
involute a b h, and the method is perhaps easier and more accurate than by unlapping a
thread from the circumference of the evolute, as above described.
Mr. Hawkins, in his Appendix to Camus' Treatise on the Teeth of Wheels, recommends a very simple
instrument for striking involute teeth. Two views of this instrument are given in Figs. 2064 and 2065.
In these a b is a piece of watch-spring, with two teeth cc, formed upon its edges; at a is a small screw
by which the spring is attached to a templet formed of thin board, and equal to a sector of the circle
upon which the involute is intended to be generated. At b a small bit of wire is inserted into the
spring, to form two knees as a handle by which the spring can be kept stretched. The templet is equal
in the thickness to the width of the spring.
In using the instrument, the templet is to be fixed upon the drawing board or surface upon which the
involute is to be traced; the centre f coinciding with the axis of the wheel, or its representative on the
drawing board; then by holding the knobs b as a handle, and keeping the spring thereby tightly
stretched, so that it remains a correct tangent to the circle, and lapping the spring upon the are of the
templet, one of the points c will trace upon the surface over which it passes a curve which, when the
point has arrived at the circumference of the pitch circle represented by the templet, will be a true
involute of that circle.
If the tracing instrument be now turned over, the opposite tooth c on the side of the spring now un-
dermost, will, by repeating the same operation, trace the counter involute for the other side of the tooth
of the wheel.
Mr. Hawkins' mode of proceeding to draw the outlines of a pair of involute wheels with his tracer is
simple, and may be explained by reference to Fig. 2062. Having drawn the line of centres A B, and
divided it at c into parts A c, Bc, proportionate to the intended velocities of the two wheels, next draw
the right line dd cutting the line of centres at c, and making with it an angle deviating not more than
20 degrees from a right angle. From centre A describe a circle touching the line d d at d within the
pitch circle of that wheel, and which will thus have dd as a tangent at d. In like manner from B as a
centre describe a circle touching the same straight line at d within the pitch circle of that wheel, and
also having that straight line as a tangent. Then the distance between the two circles is the proper
length of the teeth, from which, however, the necessary clearance ought to be deducted. The two cir-
cles last drawn are likewise the bases upon which the involutes for forming the boundaries of the teeth
are to be generated.
Next, having provided two involute traces made in the way above described, each with a templet
corresponding to a sector of the base circle of its wheel, the centre f of the templet is to be applied to
the centres A or B of the wheel of the pair to which it belongs, and meeting the points d; then sup-
posing the templet for A to be first used, let it be adjusted until the tracing point c of the spring coin-
cides with some point as d of the base circle of the wheel B, by moving it until it meets the circum-
ference of its own base circle at b, the side db of the tooth dc b will be formed, and of the proper
length, by moving the templet spring over the space included between the exterior of one base circle
to the other. By turning over the templet, and adjusting it for the required thickness, the outline of
the opposite side of the tooth may be traced in the same manner. Repetition of the operation with the
templet of B will give the form of the teeth of that wheel.
If thought desirable all the teeth of the pair may be drawn in the way indicated, or a single tooth
of each wheel may be accurately drawn, and two pattern teeth cut to the forms thus found.
Mr. Hawkins states that teeth formed according to this method will communicate equable motion
from either wheel to the other, without possessing any tendency to press the shafts outwards-which
tendency would exist if the angle of the common tangent (dd) of the two base circles deviated much
more than twenty degrees from a right angle with the line of centres.
If the teeth of both wheels are to be of equal thickness at the base, which they ought to be when of
the same material for the sake of equal strength, the part df of the common tangent ought to be bi-
sected in the middle c of its length, and the involutes drawn in the way described will give the roots
of the teeth so nearly equal, that a very slight correction only will be required-the amount depending
on the relative diameters of the wheels. But when the teeth of one wheel are required to be thicker
than those of the other, the part df of the common normal d d must be unequally bisected in propor-
tion to the required difference.
It is finally to be observed that the teeth may have their bases in any other circles than those given,
since the radii of the generating circles are entirely arbitrary; but the proportion taken is found to
satisfy the conditions required with very little outward action. In respect to the character of the in-
volute curve as compared with the epicycloid, it is obvious that the former possesses the advantage
that a greater number of teeth of equal strength may be given to a wheel by this than the epicycloidal
form; for with the latter the space must be at least equal to the tooth, while not much more than half
the space is required to be marked off on the base circle for an involute tooth of the same length. There
are also more teeth engaged at the same time, and thus the strain is divided.
Teeth of a rack and pinion.-A rack, as before observed, may be regarded as a wheel of infinite
diameter. The teeth may, therefore, be defined by the epicycloidal method explained for spur-wheels,
by making their planks straight, and the teeth of the pinion involutes. Now, the properties which have
been shown to belong to involute teeth manifestly obtain, however great may be the dimensions of the
pitch circle of their wheels, or whatever disproportion may exist between them. Thus of the two wheels
A and B with involute teeth, which work together, let the radius of the pitch circle A c, Fig. 2066, of one
become infinite; its circumference will then become a straight line represented by the face of a rack.
But whilst the radius A c becomes infinite, the radius A D of the circle from which its involute teeth are
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struck, and which bears a constant ratio to the first, will also become infinite, and therefore the invo-
lute m a will become a straight line, perpendicular to the pitch line at a. For it is evident that the
extremity of a line of infinite length, unwinding itself from the circumference of a circle of infinite
diameter, will describe through a finite space a straight line perpendicular to the circumference of the
circle. The involute teeth of the rack will,
therefore, have their faces perpendicular to
2066.
the pitch line; and this line will be deter-
B
mined by drawing a tangent to the circle on B
through the point of contact from which the
involute teeth of the pinion are to be struck. If
the radius B m, with which the involute circle
m
of the pinion is described, be equal to the
radius of its pitch circle, the line D m will
become parallel to the face of the rack, and
the sides of the teeth of the rack perpendicu-
lar to it. But in this, while the teeth of one
wheel, B, have remained unaltered, and the
accuracy of their action uninfluenced by the
change in the dimensions of the pitch circle
of the other, which has converted it into a
D
rack, and its curved into straight teeth; it
therefore follows that straight teeth upon a
rack work truly with involute teeth upon a
pinion.
But as straight teeth are not the form of
greatest strength which may be attained, and
as strength is of importance as well as uni-
formity of action, the conditions of the problem
may be examined with a view to the best modi-
fication which the form admits with respect to
this test. If with the pitch radius B c of the
pinion, Fig. 2067, we describe the pitch circle,
and draw MN a tangent to it at c, we next
make this right line the pitch line of the rack; and, further, describe the circle whose radius is Bh,
making this last the base of an involute h then if the tooth of the rack be bounded by a right line
h D E, making an angle BDM with the pitch line equal to Bch, and the involute h b be moved into
the position h'b', it will drive the sloped tooth to the position P m, always touching it in the line h c H;
and the velocity of the circumference of the pitch circle will always be equal to that of the pitch line.
A wheel with involute teeth will work truly
with a rack whose teeth are straight-sided, and
2007.
inclined to the pitch line at an angle 0, pro-
vided only
radius of base
Bh
sin
Θ.
radius of pitch circle Bc
In a rack of this kind, the locus of contact of
the teeth being the tangent line h H, the
sloping teeth will be pressed downwards by a
B
certain portion of the working pressure, which
in some cases may be an advantage in itself
by neutralizing vibration, and the advantage
of a greatly increased form of teeth is at the
same time secured.
b
The teeth of the pinion being of the regular
epicycloidal form, the faces of the teeth of the
P
P
rack will have a cycloidal form. But accord-
M
N
ing to the usual method of setting out racks
P
c
D
and pinions, the pitch line of the rack is the
V
locus of contact, and the action on one side of
the line of centres is confined to a constant
H
point in the rack tooth, which is thus subjected
to rapid wear. This disadvantage may be abridged by reducing the length of the teeth of the pinion,
but it may also be entirely avoided by taking a constant generating circle, and employing it to describe
cycloidal flanks for the rack teeth by rolling on its pitch line, and then by describing the faces of the
teeth of the pinion with the same generating circle, in the manner before described. By this simple
modification, the contact will no longer be confined to the pitch line of the rack, but will be distributed
over the flanks of its teeth and these, it may be observed, may be made of any length desired, by
regulating the diameter of the generating circle accordingly. If the generating circle have a diameter
equal to the radius of the pinion, the flanks of the pinion-teeth will then be radial, and this form may
1. also be modified by taking a circle of greater or less diameter.
To determine the pitch circle of the pinion, let D represent the distance through which the rack is to
be moved by each tooth of the pinion, and let these teeth be in number = N; then will the rack be
moved through the space N X D during one complete revolution of the pinion. Now the rack and
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GEERING.
pinion are to be driven by the action of their teeth, as they would by the contact of the circumference of
the pitch circle of the pinion with the plane face of the rack, 80 that the space moved through by the
rack during one complete revolution of the pinion must precisely equal the circumference of the revolv-
ing pitch circle; consequently, calling R the radius of the pitch circle of the pinion, we will have
NXD
2 = R = N X D
Two of these quantities being given, the other immediately becomes known. Thus, let D=2 inches,
and N = 13, then
=4.188
inches.
Annular wheel and pinion.-An annular wheel is one having its teeth formed within its periphery,
and consequently the pinion works internally. In this arrangement, the form of the teeth may be de-
termined according to the principles already explained, with very slight modification in their practical
application.
Thus, in Fig. 2068, let AB be the centres of the wheel and pinion; and let c be the point of contact
of the pitch circles. The epicycloid m described by the circle having a diameter = B c, gives the
lateral form of the tooth of the wheel, limited as before by a radius drawn to the middle of the thickness
of the tooth; and an arc described from the centre B, with radius A n, cuts the circumference B c at a
point which determines the side of the tooth of the pinion at n. But if we attempt to apply the same
process to finding the face of the tooth of the pinion as we have employed in determining the flank of
the wheel-teeth, we shall find that the construction will either not give the side of the tooth as the arcs
do not meet, or it will give it a position upon the radius A c on the same side as the face cm. From
this, then, it appears that the teeth of the wheel will have no flanks, and that their outline will consist
simply of faces. From this it follows that the pinion would not drive the wheel uniformly according to
the required condition, and in consequence we must find another curve for the faces of the teeth of this
last. Now if we trace the epicycloid by a point c of the circle to centre A in the figure, rolling it exter-
nally upon the circumference of the circle on B, it will give the outline of a tooth capable of fulfilling
the condition of uniformity of action at any point of the circumference of the circle on A. Should the
teeth engage before the line of centres, the tooth of the wheel would necessarily act constantly at that
point and cause great wear, particularly as this species of geering is usually employed in conveying the
motion of water-wheels where it is exposed to incessant wetting and vibration.
In practice it is found sufficiently accurate to substitute for the epicycloidal method above described
for finding the form of the face of the tooth of the pinion, the more convenient mode of defining it by an
are of a circle drawn from the root of the tooth, with a radius equal to the chord of the pitch.
When the teeth do not engage until they arrive at the line of centres, the faces of the teeth of the
pinion may be entirely suppressed, leaving the flanks only, which are alone acted upon by the teeth of
the wheel. This may be uniformly done, at least when the pitch of the pinion is small, and when the
wheels are more than strong enough for the power which they are required to transmit. In such cases
the following method of setting out the teeth of the pair may be adopted with safety.
2069.
2068.
B
d
a
P
of
m
m
n
n
c
mg
In Fig. 2068, let A be the centre of the wheel, and B the centre of the pinion as before. From the
point c of contact of the two pitch circles mark off the arcs c a, b, equal respectively to the pitch of the
pinion and wheel join a B and b a, and bisect this last; from the point of bisection raise a perpendicu-
lar, and the point d, where this meets the pitch circle of the wheel, will be the centre from which the
arc a b, defining the side of the tooth of the wheel, may be struck. The flank of the tooth of the pinion
is determined by the two radii which limit its thickness and meet in B. To define the length of the
teeth, it is sufficient to describe a circumference with the radii Ar, Bn, leaving sufficient bottom clear-
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GEERING.
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ance and the extremities of the teeth of the pinion, and the bottoms of those of the wheel, ought to be
rounded off by ares drawn with a radius equal to the chord of the pitch taken upon the pitch circle of
the pinion.
By this method it will be seen that the strength of the pinion-teeth is greatly reduced, and ought
therefore only to be applied when the power to be transmitted is comparatively light, and when the
wheel drives the pinion. It is consequently not recommended for general practice. The epicycloidal
method, explained for external wheels, may, on the contrary, be applied in all cases, observing that in
the case considered, the space answers to the tooth, and conversely, the tooth to the space; 80 that
keeping this distinction in view, the forms of the teeth may be determined with as much readiness as if
the pair were of the ordinary kind of spur-geer. The teeth may also be set out with the Odontagraph,
if that instrument be in use in the pattern shop.
There is one property of the internal pinion which may be here pointed out, namely, the diminished
friction which attends its working, as compared with an external pinion of the same diameter. To
render this obvious, let PP, Fig. 2069, be the pitch circle of the wheel, QQ the pitch circle of an internal
pinion, and Q'Q' that of an external pinion of equal diameter. Then supposing the wheel to drive, and
that it moves until the point a arrives at b; by this advance, the same point of the pinions will have
arrived respectively at d and c of the circles Q Q and Q'Q', having both moved over a space equal to
ab. Now it is manifest that the distance from b to c is less than the distance from b to d; but these
distances may be assumed as the measure of the amount of slide of the teeth of the respective pinions
in moving to their new position; for whatever may be the actual amount of slide, it must evidently be
in the ratio of bc to bd, since these quantities measure the velocity of the sliding contact of the pair;
and since, when the circumstances are otherwise identical, the friction is as the space passed over. It
is, therefore, evident that the internal pinion has less friction than the external one; and the same figure
may be employed to show that it has a larger arc of contact with the wheel, and is, therefore, other
things being equal, stronger than the external pinion.
Teeth of bevel-wheels.-When a cone is made to revolve upon the surface of another fixed cone, in
such a manner that their summits always coincide, the curve which is generated by a point in the cir-
cumference of the rolling cone is a kind of epicycloid, which will plainly lie on the surface of a sphere
whose centre is the common apex of the cones, and whose radius is equal to the slant side of the rolling
cone. From this property the curve is termed the spherical epicycloid; and if the cone roll on the
concave surface of the base, the curve produced is denominated the spherical hypocycloid.
2070.
R
h
h
a
t
m
B
To apply this definition, let there be two cones in contact along their slant sides A c, Fig. 2070; and
let c A a be any other cone, having its line of contact coinciding with A c, and having its apex at A; the
axes of these three cones will then be in the same plane A RB. The circumferences will also be at the
same distance A c from A, and will lie on the surface of a sphere whose centre is A and radius A c.
Now, suppose the three cones to revolve above their respective axes with the same relative velocity
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GEERING.
as would be produced by the rolling contact of their surfaces, it is clear that the line of contact will
constantly be Ac, and calling a A c, Fig. 2070, the describing cone, a line db upon the circumference of
the surface of this directed to the common apex A, will generate one surface fbdt on the outside of the
cone A c m, and another surface dehb on the inside of the cone c Ar. These surfaces will touch along
the describing line b; for since f d b is generated by the rolling of the generating cone on the cone
m Ac, the motion of db is at every instant perpendicular to the line of contact A c, and therefore the
normal plane at d to the surface generated by that line, must pass through the line of contact A c
In like manner the normal plane to the surface h e db will pass through the line of contact of the cones,
and consequently the surfaces must touch along db.
Now, under these conditions, it is clear that if the rotative motion of the cone m A c be communicated
by teeth to the cone c A r by their contact action, the teeth being generated by the describing cone a A c,
the motion will be the same as that produced by the rolling contact of the conical surfaces, for at the
beginning of the motion ft and e h coincide with the line of contact Ac; and since the arcs cf, ce, de-
scribed by the bases of the cones, are, respectively, equal to d, and therefore to each other.
3
2071.
4,
€
k
y
4
In practice the portion of spherical surfaces occupied by these arcs, when employed as teeth, are
narrow belts of the cones extending only a small distance within the circle of the bases, and therefore
cones tangent to the sphere along cm and cr may be substituted for the sphere itself without
practical error. Thus draw R c B perpendicular to the line of contact A c, and intersecting the axes of
the two cones at B and R; then B R revolving about A B will generate a conical surface tangent to
the sphere along the base cm; and the same line R B revolving about A R will generate a conical
surface tangent to the sphere along the base cr of the cone c Ar. And since the arc df, which really
lies in the spherical surface, is very short, it may be supposed, without sensible error, to lie in the sur-
face of the tangent cone c Bm, and to be described with a circle whose diameter is equal to that of the
base of the describing cone. And, in like manner, the arc d e may be supposed to be similarly de-
scribed upon the surface of the tangent cone c Ar.
These principles furnish us with a ready mode of obtaining the form of the teeth of a pair of bevel-
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GEERING.
831
wheels. Thus let AP and AQ be the axes of the shafts between which the motion is to be trans-
mitted. The angular velocities with which the two shafts are driven being determined, draw A D such
that it divides the angle PA Q into two parts, proportional to the numbers of teeth in the wheels
respectively, or inversely proportional to the angular velocities or numbers of turns per minute of the
wheels on the shafts. If we conceive the line A D to revolve about the axis AP, at the same angle
PAD, the conical surface A DE will evidently be described, a portion of which, E d, is represented
in Fig. 2071. Similarly, by the revolution of the line A D about the axis AQ, the conical frustum
F fd will be described. It is obvious, therefore, that these two cones, communicating the motion by
simple contact, will transmit motion in the given ratio, and hence they are termed the primitive cones,
and have an obvious analogy to the primitive circumferences or pitch circles of spur-wheels. In the
interior of their mass the flanks and spaces are conceived to be formed, and upon their surfaces are
placed the projecting faces of the teeth-the returning surfaces and F n of the cones, or the crowns,
as they are termed, are defined by inverted conical surfaces formed upon the bases DE and DF; they
are short frusta of the cones BDE and CDF, the common apex of which is determined by the line
BDC drawn at right angles to AD. To perceive the propriety of this form of the crown, it is only
necessary to consider that the ends of the teeth Em and Fn will thus always be square with the sur-
face of the primitive cones, and they will geer most completely into each other. The other ends of the
teeth are defined in like manner by the conical recesses and dcf, which are parallel to the exterior
surfaces of the crowns; the line bdc being, like the exterior line, at right angles to A D.
It appears, then, that the true forms of the teeth may be described with facility upon the surfaces
of the cones DEB and DFC; and for our present purpose of representing the forms of these teeth
upon a plane surface, it is only necessary to conceive those surfaces spread out or developed upon a
plane. Now, the development of a cone, that is, the form assumed by the superficies when laid out
flat, is a sector of a circle, of which the radius is equal to the slant height of the cone, and the arc equal
to the circumference of the cone at the base. In the case before us, therefore, if a circular arc DG be
described from the centre C with the radius CD, it will be the development of a portion of the base,
and the sector CDG will likewise be the development of a portion of the cone; and by describing an
arc kg with the radius Ck or Cg, the annular space contained between k and DG will be the de-
velopment of the crown of the wheel. It is upon this annular segment, then, that the forms of the
teeth may be drawn precisely as if it was a part of a spur-wheel; and if we suppose a piece of sheet
copper or other suitable material to be cut into the form of the teeth, and wrapped upon the crown of
the wheel, the outline which could thus be traced off would represent the true forms of the teeth of the
bevel-wheel.
The breadth being settled by the same rules as for spur-wheels, it is obvious that the teeth must
follow the taper of the cone towards the point A. Draw dk parallel to A C, and from the centre C
describe the arc then, as before, the segment Ckg will be the development of a portion of the
cone and upon this segment the forms of the upper ends of the teeth may be described. Lines
drawn from the teeth on the are DG to the centre C, will determine the magnitude of the teeth on the
arc kg, and the teeth may thence be described, as in the figure.
The largest diameter DF is reckoned the diameter of the wheel, and, similarly, DE is said to be
that of the pinion. The process which we have detailed for describing the teeth of the wheel is pre-
cisely the same as that for describing the teeth of the pinion. It is unnecessary, therefore, to particu-
larize further, than that Fig. 2071 shows the teeth of the pinion drawn similarly to those of the wheel,
upon the arcs D H and ih.
That the teeth thus formed will work truly together, becomes obvious, when we reflect that if any
two exceedingly thin wheels, with the form of teeth described, had been taken in a plane perpendicu-
lar to A D passing through the point D and having their centres in the axes of the given wheels, they
would work truly together, and their angular velocities would be in the given ratio. Now it is evident
that the portion of each of the conical surfaces which is at any instant passing the line k i is at that
instant revolving in the plane perpendicular to A D which passes through the point D, the one surface
revolving in that plane about the axis A C, and the other about the axis A B. Those portions of the
teeth of the wheels which lie in these two conical surfaces will, therefore, drive one another truly, at
the instant when they are passing through the line ki, if they be cut of the form which they must have
had, in order that they might drive one another truly and with the required angular velocity, had they
acted entirely in the plane perpendicular to AD and about the given axes. But this is precisely the
forms in which the teeth are supposed to be cut, and therefore those portions of the bevel teeth which
lie in the conical surfaces will drive one another truly at the instant they are passing through the line
ki and, therefore, they will drive one another truly through a small arc on either side of that line,
which is the condition required, since it is only through an exceedingly small distance on either side of
that line that any two given teeth remain in contact. It therefore follows, that those portions of the
teeth which lie in the conical surfaces Df, De, work truly with one another throughout the whole
breadth of the conical belt.
If the radius of the base of the frustum be called R, and the radius of its developed circle be r; also if
the semi-angle C A D of the rolling cone = Θ; then = R Θ Hence the action of the teeth in any bevel-
COS
wheel is equal to that of a spur-wheel whose radius = cos Θ' R and if N be the number of teeth in the
bevel-wheel, N Θ will be the number of those in the spur-wheel of equal action. Thus if 0 = 50°,
cos
then R = 64279 1 = 1.556, and therefore the action of a bevel-wheel of 50° is fully equivalent to
CO3
that of a spur-wheel having a radius one-half greater, and consequently a half more teeth.
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This, then, is a reason for the superior action of bevel-wheels, as compared with spur-wheels of the
same number of teeth; for spur-wheels always act the better the more teeth they have, and it appears
that the bevel-wheel is always equivalent in its action to a spur-wheel of a greater radius, and conse-
quently a greater number of teeth.
When a pair of bevel-wheels have equal numbers of teeth, and have their axes at right angles to
each other, they are termed mitre-wheels. In this case Θ = 45° and COS 0 = 70711 ; therefore taking
1
radius
equal
unity,
we
have
= 14; in words, the action of a meter-wheel is nearly equivalent to
cos 0
that of a spur-wheel, with half as many teeth.
Skew-bevels.-When the axes are inclined to each other, and yet do not meet in direction, and it is
proposed to connect them by a single pair of bevels, the teeth must be inclined to the base of the frusta
to allow them to come into contact.
2072.
To find the line of contact upon a given frustum of the tangent-
cone; let the Fig. 2072 be the plane of the frustum; a the centre.
Set off ae equal to the shortest distance between the axes, (called the
eccentricity,) and divide it in c, 80 that a c is to ec as the mean radius
of the frustum to the mean radius of that with which it is to work
draw p perpendicular to ac, and meeting the circumference of the
conical surface at m; perform a similar operation on the base of the
frustum by drawing a line parallel to c m and at the same distance ac
from the centre, meeting the circumference in p.
The line pc is then plainly the line of direction of the teeth. We
are also at liberty to employ the equally inclined line cq in the op-
posite direction, observing only that, in laying out the two wheels,
the pair of directions be taken, of which the inclinations corres-
pond.
Fig. 2073 renders this mode of laying off the outlines of the wheels at once obvious. In this
figure the line a e corresponds to the line marked by the same letters in Fig. 2072; and the division of
it at c is determined in the manner directed. The line c m being thus found in direction, it is drawn
78
2073.
indefinitely to d. Parallel to this line and from the point c draw e to e, and in this line take the centre
of the second wheel. The line c m d gives the direction of the teeth; and if from the centre a with
radius at a circle be described, the direction of any tooth of the wheel will be a tangent to it as at c.
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833
And similarly if a centre e be taken in the line E d, and with radius e d = c e a circle be drawn, the
direction of the teeth of the second wheel will be tangents to this last, as at d.
Having thus found the direction of the teeth, their outlines may be described exactly as in the case of
ordinary bevel-wheels, and with equal exactness and facility.
Wheel and tangent screw.-This is often a very convenient and ready mode of reducing a high
velocity.
To determine the form of the teeth of the wheel and thread of the screw, it may be remarked that,
from the nature of the screw, the section of its thread, made by a plane passing through its axis, is
everywhere the same; and that if a series of such sections of the entire screw be made by planes at
equal angular distances round the circle, a set of figures, resembling a double rack, will be obtained
alike in the number and form of their teeth, but in which the teeth will approach nearer and nearer to
the extremity of the screw. Now, while revolving, the screw successively brings these sections into
operation upon the whole teeth, producing exactly the same effect as if the screw were pushed endlong
without rotation, in the manner of a rack. But this supposition furnishes a ready mode of obtaining the
forms of the wheel-teeth and thread of the screw, upon the principle of the rack and pinion.
In Fig. 2074 a c is the line of centres of the wheel and screw. The screw is shown in section by
a plane cutting it in the line of its axis. Now, the screw being considered a driving rack, it passes a
tooth of the wheel during each revolution, and therefore the point a will, at the end of a revolution of
the screw, be the point b; but the thread must necessarily have continued in contact with the tooth
while passing from a to b. Now, if it be required that the thread of the screw shall be in contact with
the tooth at a point only, the tooth will be straight, and its obliquity equal to the pitch of the screw.
But if it be desired that the thread shall be in contact with the entire side of the tooth, the outline of
the wheel-teeth must be different in every section perpendicular to the axis of the wheel. The required
form will be found by making such series of sections of the screw as proposed, and adapting the portion
of the side of the tooth to that particular section with which it is intended to work. And since in every
section two or even three teeth may be in simultaneous contact, the screw may be in contact along the
entire side of those teeth.
2074.
P
P
P
P
In practice, then, the form of the tooth must be determined for the respective sections of the screw,
as in the case of the rack; and the thread of the screw may obviously take the same sloped form if
great strength be required.
To find the diameter of a wheel, driven by a tangent-screw, which is required to make one revolution
for a given number of turns of the screw, it is obvious, in the first place, that when the screw is single-
threaded, the number of teeth in the wheel must be equal to the number of turns of the screw. Conse-
quently, the pitch being also given, the radius of the wheel will be found by multiplying the pitch by
the number of turns of the screw during one turn of the wheel, and dividing the product by 6-28.
When a wheel-pattern is to be made, the first consideration is the determination of the diameter to
suit the required speed; the next is the pitch which the teeth ought to have 80 that the wheel may be
in accordance with the power which it is intended to transmit; the next, the number of the teeth in
relation to the pitch and diameter; and, lastly, the proportions of the teeth, the clearance, length, and
breadth.
The size and proportions of the wheel being thus settled, the operation of constructing the pattern is
ready to be undertaken. Let us, in the first place, assume that the wheel is to be a radial one with six
105
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arms, and here it must be premised, that the number of arms increases according to the diameter of
the wheel-thus, with occasional deviation:
Wheels from 11 to 31 feet diameter have 4 arms.
"
from 31 to 5 feet diameter have
5
"
"
from 5 to 84 feet diameter have
6
"
"
from 81 to 16 feet diameter have
8
"
"
from 16 to 24 feet diameter have 10 "
It is assumed in the numbers of this table, that the wheels are cast complete, the boss supporting the
arms, and these last the rim with the teeth cast upon it. The cases of deviation are those in which the
wheels are very small, and cast with a continuous web, instead of radial arms, and where the wheels are
required to be particularly light, and to possess great accuracy: it is in this case preferable to increase
the number of arms, so that they may be made thinner, and thereby incur less risk of the rim being
drawn out of form during the cooling of the metal
In arm-wheels the rim is always built of segmental pieces, cut out of plank of convenient thickness,
to an external radius equal to the pitch radius of the wheel, which allows a depth equal to the flanks of
the teeth for dressing. A templet or mould is, in the first place, made of thin, well-seasoned and dry
board, and by this the form of the building segments is drawn upon the wood from which they are to
be cut. Suppose that the rim is of such breadth that six thicknesses of wood are required to make it
up; then four segments are cut of the requisite breadth and to the same internal radius, and two of
them to an internal radius less than the former by at least as much as the intended thickness of the rim.
With these segments the rim is to be built in the following manner :-
A circular plate of wood, with an iron centre on the back of it, usually with an internal screwed boss
on the centre of it, having the same pitch of thread as the thread of the screw on the projecting end of
the lathe-spindle, is prepared and turned up truly on the face. A circle is also described upon it to
indicate the pitch line of the wheel, and to this circle the exterior arcs of the rough segments are to be
adjusted.
Thus prepared, the first course of segments are planed true on one side, and fitted with sprigs upon
the plate, their ends accurately jointed together, glued, and sprigged. When the glue is in some de-
gree set, the plate is put upon the spindle of the lathe, and the segmental ring is turned true on the
flat side; but the interior and exterior circumferences are left in their rough state. The plate is then
removed from the lathe-spindle-usually a simple spindle with not more than two speeds upon it.
Another course of the segments is now dressed with the plane on one side, and built upon the first.
This course is bedded with glue and sprigged to the first course, observing that the joints of this course
do not coincide with those of the first, but that all the former joints are covered by the whole wood O2
the last-laid course. The glue being allowed time to set, the plate is again put upon the lathe-spindle,
and the face of the ring is dressed as before, still leaving the circumferences in their rough state.
The segments of these two courses are of the same breadth, but the next course to be laid must have
the increased breadth necessary to form the web or feather of the rim; this, as already stated, is usually
made equal in breadth to the thickness of the rim. This course will, therefore, project inwards over the
ring formed by the two courses already laid. In other respects, however, it is not different, and it is
laid and fastened in exactly the same manner as the second course.
Two courses are laid of these broader segments; afterwards two others of segments of the same
breadth as the two courses first laid. This done, the building of the rim is complete, and a cross sec-
tion of it would present the appearance shown by the part a dbc, Fig. 2075, and an arc of it in elevation
2075.
2076.
a
3
c
6
5
4
3
R
2
1
c
a
d
is represented by the part A b, Ba, Fig. 2076. In Fig. 2075 the courses are numbered in the order in
which they are supposed to be laid, the layers 3 and 4 being those which are intended to form the web
of the rim.
This process being completed, and the face-plate placed on the lathe-spindle, the exterior edge of the
rim and half the interior circumference, that is, the interior of the three courses marked 4, 5, 6, are
turned true to the required form. The rim is then taken off the face-plate and reversed: but is now
fastened to the plate by screws passed from the back of the plate into the edge of the rim. In this
position the interior of the other half of the breadth of the rim is dressed, that is, the inner circumfer-
ences of the layers 1, 2, 3, when the rim is ready to have the arms fitted into it.
In being dressed, the web or feather formed by the two middle layers, 3 and 4, is diminished in
thickness, till at their edge they are together exactly of the same thickness as the arms which are to
be put into the pattern; and a good practical rule is, to make these equal in thickness to seven-eighths
of that of the rim of the wheel In breadth they ought to be equal, at least, to the breadth of the
rim, when this is calculated according to the rule of maximum strength already pointed out, and
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towards the centre should be increased to Iths of that breadth. More commonly they are made equal
in breadth to the rim, and tapered to fths of that breadth at their extremities.
The breadth of the arms being determined, they are to be fitted into the rim by a half-check upon
the web, which is done by checking out at six points, answering to the number of the arms, the breadth
of an arm in the web layer marked 3. The extremities of the arms are then checked to the same
depth, and fitted into their places with a little glue, and two short but strong screw-nails at each end.
The mode of fitting the arms together is different in different shops; but the easiest mode is to fit a
double arm in the manner described-that is, an arm extending through the diameter, and having a
half-check at the middle of its length cut to the proper angle to receive the second double arm extend-
ing, like the first, through the complete diameter. These being fitted in, two half-length arms are then
inserted, butting into the wide angles left at the centre between the arms already fitted. Fillets are
next inserted to fill up and round off the acute angles, both at the centre and extremities of the arms
these are intended to give additional strength to the wheel, and to facilitate the extraction of the
pattern from the sand in the process of moulding. Were the acute angles left open, the sand would
be ready to break down and give the wheel an uncouth and rough appearance, a result which is to be
guarded against in all kinds of moulding, and more especially in wheels.
The flat arms being thus fitted in, the next operation is to insert a centre, upon which the boss or
eye of the pattern may be at any time built according to the size necessary for the particular wheel to
be cast off the pattern. The centre is formed of two hexagons, one laid on each side, and built of six
separate pieces, or made of single solid blocks of half the depth of the rim, so that on each side the
centre projects beyond the plane of the rim by half the thickness of the flat arms. The centre is firmly
screwed together, and to the arms of the pattern; and on one side-the side which is intended to be
uppermost in the process of moulding-a flat plate of iron, usually of the same form as the centre
itself, is indented and fastened with screws to the wood. This plate has a hole in the centre, intended
to admit an iron prong for starting and lifting the pattern out of the sand.
The next operation is to attach the feathers of the arms. These are placed along the middle of the
flat arms, the planes of the two being at right angles to each other, so that their cross section at any
point is represented by +. The breadth of the feathers diminishes from the centre towards their
extremities, in exactly the same ratio as the flat arms; at the centre they are half the width of the
rim, and consequently stand flush with the depth of the centre, but at the extremities which meet the
rim the width is reduced a sixth. Fillets are fitted in to fill up the angles which the ends thus form
with the inside of the rim, for the reasons already stated. Small running fillets are likewise fitted
into the angles which they form with the flat arms.
The interior of the pattern may now be considered as finished; and it may be remarked that it is
always desirable to have the arms completely fitted and secure, before commencing to turn the exte-
rior of the rim; for should the rim be dressed on the outside previously to the arms being put in-
which is practised by some makers-it is hardly possible to prevent its springing, and being thrown
out of truth. By the process described, the arms are fitted in while the exterior of the rim is in its
rough state, and consequently, although it should slightly spring, the external and most important cir-
cumference will be brought to the truth in the after process of turning. The rim is also stronger and
less liable to be thrown from the truth, while in the rough state, than it is after being finished to the
thickness.
After the arms are fitted into the interior of the wheel, and finished in the manner described, it is
taken from the face-plate; a hard-wood plate, with a centre for the lathe-spindle, is screwed upon the
eye of the pattern; it is then placed in the lathe, and the exterior of the rim is turned to the required
thickness. In this process it receives a very slight bevel-usually from an eighth to a tenth of an inch
in a foot-to allow it to draw cleanly from the sand in the process of moulding. About the same frac-
tion is allowed upon the diameter of the pattern for contraction of the metal in cooling.
The next part of the operation is to cut the dovetail seats of the teeth. The form of these recesses
is shown in Fig. 2076, beneath the teeth. They extend completely across the breadth of the rim, and are
intended to receive the dovetail pieces (bd, Fig. 2075) on which the teeth are fixed. The dovetail
pieces are themselves made of hard wood, and besides being otherwise convenient, they serve to bind
the several layers of the rim firmly together.
These pieces are, in the first place, accurately fitted into the seats and marked, so that every piece
may be replaced inserted into the proper groove to which it was fitted; the rough pieces of which the
teeth are to be formed—these being cleaned with the plane on one side-are then fitted, each with
a dovetail fastened by screws to its dressed side; and being cut nearly to the proper length, they are
fitted into their places by the dovetails, which are made with a slight taper, 80 that they can be the more
easily driven in its seat, and taken out again when required. The blocked teeth being thus all placed
and partially fixed upon the circumference of the pattern, this is again placed on the lathe for the pur-
pose of dressing off the ends and points of the teeth. This done, the pitch circle of the wheel is finally
marked off upon the ends of the teeth with a fine point.
The pattern is now ready to have the form of the teeth drawn in, as represented in Fig. 3, by an
arc of the rim, at this stage, with the outlines of the teeth also drawn. In this figure the pitch line is
denoted by the dotted circle pp, and the form of the teeth is denoted by the shaded portions of the
rectangular blocks. The various methods of obtaining the outline have already been fully explained.
To finish the pattern, it therefore only remains to dress off the teeth to the forms indicated, and to
fix the dovetails permanently in their beds. This last is easily effected by a film of glue; and if the
teeth are to be finished by the wheel-cutting machine, it ought to be performed previous to placing
the pattern in the lathe for the purpose of dressing the ends and points of the teeth, and consequently
before pitching them. But when the teeth are to be finished by hand, the order of the operation is
that described and the most commonly practised.
In finishing the teeth by hand, they are removed in succession, by driving out the dovetails, one only
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GEERING.
at a time; the unshaded portions of the block are then accurately dressed off by concave and convex
guge-planes adapted to the purpose; the dovetail is then fitted into its bed with a film of glue; and
the tooth is complete. Every tooth is treated in exactly the same manner, until the whole number be
dressed and fastened upon the circumference of the rim. But unless the operation of fixing the teeth
be performed with care, there is danger of twisting the rim and throwing it out of truth.-To guard
against this, the safest practice is to take always in succession the pair of teeth opposite to each other
on the circumference: that is, having fitted a tooth on one side of the pattern, the tooth opposite to it
on the other side ought to be the next taken, so that any tendency of the glueing to twist the rim at
one point will be neutralized by an opposite tendency in fitting the next tooth-The wheel pattern
may now be considered complete.
It is to be remarked, that in making the pattern of a cast-iron wheel, it is necessary to take into
account the nature of the material: the pattern must not only be of such a proportion of parts as to
be sufficiently strong, calculated by the series of the parts; it must also be 80 proportioned that the
fluid metal, when poured into the mould, shall set in every part as nearly as possible at the same
instant. For if the parts contain disproportionate quantities of metal, it is plain that the thinner parts
will cool more quickly than the others; and as cooling is attended with contraction, the parts of the
casting will be put upon strain, from their contracting irregularly and faster at one point than at
another; and if the irregularity be carried to a certain extent-and the limits are not wide-the cast-
ing, on being removed from the mould, will be found fractured through some of the thinner and first
cooled and first contracted parts. Thus, one of the most common errors is to put too much thickness
into the boss of the wheel, and in consequence it not unfrequently happens that the arms are drawn
away from the rim. To avoid this, the metal round the eye ought never to be more, in arm-wheels,
than twice the thickness of the rim; that is, equal to the pitch of the teeth, and this is quite sufficient
in strength to resist the driving of the keys in fitting the wheel on the shaft, provided this operation
be done with ordinary skill and care.
To prevent the bad effects of unequal contraction, the arms are sometimes made of a curved form.
When the wheel is very light in proportion to its diameter, the arms are advantageously made with
a double curve like the old letter f, which admits extension to a certain extent, depending on the
elasticity of the material, in the direction of its length, without fracture.
The rules and directions which apply
2077.
to spur-wheels, likewise apply, with
C
slight technical modifications, to bevel-
wheels. The mode of laying down
the working drawings of a pair of this
kind has been already explained and
figured in relation to the manner of
obtaining the form of the teeth; and
the proportion of parts may be depicted
in connection with the same drawing,
by substituting for the primitive cones
there given, a section of the pair as
represented in Fig. 2077.
Here A P is the common pitch line
of the pair, determined as before de-
scribed; and BP, CP are the radii of
the wheels. The breadth of the rim
of the wheel is marked off from P B
towards A, and through that point the
P
perpendicular bb' is drawn. Another
perpendicular to the same line is
drawn through the point P, and of
course parallel to bb'. Upon these
perpendiculars to the pitch line AP,
the lengths of the teeth are set off, and also the thickness of the rims, as indicated by the lines a b,
a'b'. The distance a a' will be the length of the tooth plus the bottom clearance; the space inclosed
between a or a' and the pitch line the length of the flank of the tooth; and from the pitch line to the
dotted lines at a and a' is the measure of the addendum of the teeth. The thicknesses of the rim
and arms are in the same relation as for spur-wheels; but in this case they are not placed opposite the
middle of the rim and boss as before, but entering on one side of the smallest diameter of the wheel,
with the feather entire and projecting outwards, 80 that a cross section of the arm complete would
present the appearance T. the horizontal line indicating the face-arm, or web, and the vertical piece
the feather of the same. The boss or centre of the wheel is built in the manner already described, and
of the same relative proportions, but altogether on the side which is furthest from the apex of the ideal
cone, of which the wheel is a frustum. The feather of the arm is inserted upon the same side, and is
of equal breadth to the face-arm. This is commonly sweeped by a double curve, as in the diagram,
Fig. 2077, but often it is simply tapered from the rim till it meets the central boss, which, in well-
proportioned wheels, is usually equal to the breadth of the rim plus the thickness of the face-arm.
The mode of building the rim, which, with the exception of the teeth, forms the only practical differ-
ence between wheels of this class and spur-wheels, will be understood from Figs. 2078 and 2079. which
show the order of position of the segmental rings in plan and section. The segments of the ring
marked 4 being cut to the proper breadth, according to the thickness of the wood used, they are
sprigged to the face-plate, and dressed on their exterior surface, as before explained. But in the oper-
ation of dressing, their internal edge is commonly cut away to the diameter at which the next course
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marked 2 is to be laid. This operation is not indeed essentially necessary, but it affords to the workman
a better guide than a mere surface line described with the required radius, and is done without trouble
The succeeding courses are sprigged and glued on in succession, every succeeding course being
increased in diameter according to the
angle which the side of the cone forms
with the axis; in other words, accord-
ing as the bevel of the wheel is more
or less. Usually, the first two courses
are flush on their inside circumference,
as shown in the sectional diagram of
Fig. 2079.
The rim being thus built, is next to
be dressed on its inner circumference
to the diameter required. This done,
the face-arms are half-checked into the
2078.
radial part of the ring marked 3, ex-
actly as in the case of the spur-wheel
pattern. The centre and feathers of
+
3
2
1
the arms are inserted in succession, and
2079.
before the rim is removed from the
face-plate. But as soon as these oper-
4
ations are completed, a centre-plate is
3
fitted to the pattern, and concentric
a
with it; the face-plate is then removed,
1
and the pattern is fitted on the lathe
by the centre-plate, for the purpose of having the face of the rim turned. This must necessarily
be true to the required bevel, and therefore implies additional care on the part of the workman
whose usual method is quite exact. In the first place, he turns down the edge of the course marked
1 to the required diameter; then having fixed for the apex of the imaginary cone a point or edge,
he applies a straight-edge from time to time during the process of turning, when it is evident that
so soon as his straight-edge coincides with the whole breadth of the rim, and at the same time touches
the apex and base of the cone, the operation of turning is complete, and not before this coincidence
is attained.
An easier method is, however, to turn the greatest and least diameters in succession-with which
the drawings furnish bim-and afterwards to dress down the face of the rim until a short straight-edge
touches the two diameters at the same time, and consequently coincides with the face of the rim
throughout its whole breadth. If this be not deemed sufficiently exact, a mould may be formed from
the drawing of two slips of wood so joined together as to coincide at the same time with the face-arm
and face of the rim; the greater of the two diameters being struck, as in the method first proposed,
it is evident that the mould will, on being applied, coincide with the lines on which it was found only
when these agree with the drawing.
The rim being finished by one or other of the methods described, the next part of the operation is
to make the dovetail-grooves which are to receive the dovetails of the teeth. These are cut with the
same attention to accuracy of taper as was used to determine the bevel of the rim; for as the teeth
ought manifestly to diminish in thickness as they extend towards the apex of the cone, where, if con-
tinued to that point, they would vanish, it is consistent with the general character of the work, although
not essentially necessary, that the dovetails upon which they are to be fastened take the same tapered
form. As in the spur-wheel patterns, those dovetails ought to pass through and take hold of each of
the several courses of segments of which the rim is built, and thereby act as keys to bind them per-
manently together.
When the dovetails are fitted and the teeth fastened to them, they are firmly driven into their seats;
and the teeth are dressed in the lathe on the ends and points to the required size. The external and
internal pitch lines, that is, lines coinciding with the surface of the imaginary cone of which the wheel
is a frustum, are drawn upon the ends of the teeth. Upon these lines the centres of the teeth are
marked off. next their thickness, and lastly their form is described either by the method of curves, or
by pattern teeth shaped according to the mode of development already explained. The dovetails
are then driven out, and the body of the teeth accurately dressed to the curves traced on the ends.
But this part of the operation ought to be performed in the successive manner directed for spur-
wheels, and with the same attention and precaution to prevent the twisting of the rim, which is almost
invariably the result when the teeth are fitted consecutively.
It very seldom happens that two castings are to be made from the same pattern with the same sizo
and form of eye. It becomes therefore necessary to have a ready mode of altering the size and form
of the centre according to the size and form of the eye wanted. This is provided for by making the
original and solid centre smaller than any boes likely to be required for a wheel of the particular pitch.
This allows of a temporary centre being built around the original one, of the particular size wanted
and as the eye is always taken out by a core, a print of corresponding diameter is sprigged on to guide
the founder in the size and also in the setting of his core.
It is also necessary often to have the boss and arms more on one side of the wheel than the other,
a case which cannot be provided for by making these loose. To modify the pattern for a casting of this
kind, the difference is made up temporarily, on the side to which the increase is desired, by pieces
simply sprigged to the proper arms and centre of the pattern; the quantity to be removed from the
other side is then carefully marked off by chalk lines drawn upon the feathers of the arms and round
the centre; and when the pattern is moulded, the parts so chalked off are filled up in the sand. If
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the modification, however, be of such extent as to alter the position of the face-arms, it then becomes
necessary entirely to inclose the arms with thin board, forming a species of box, of a depth determined
on the one side by the position of the arms and centre of the pattern, and on the other by the position
which they are to occupy in the casting. The pattern being moulded in this condition, there is left
only large open spaces for the arms and centre; and into these the new arms and centre are built by
cores formed by core-boxes made to the particular shape and size desired. This is perhaps one of the
greatest niceties of green sand moulding.
For wheels of small diameter and pitch, it is now becoming a general practice to use metal patterns,
of cast-iron and brass. In works where small machinery is made, and which are commonly provided
with wheel-cutting machines, the rim is usually made of sufficient thickness to allow the teeth to be
out upon it, and yet to leave the proper thickness of metal for strength between the bottoms of the
spaces, and the web-plate which connects the rim with the eye-boss of the wheel. Sometimes also the
same method is adopted with wheels which are crossed-out. This method admits of greater accuracy
than that described for large wheels; for before proceeding to cut the teeth of the wheel, the casting
may be accurately adjusted to a centre in the lathe, and have the strength of its parts at the same
time exactly proportioned to the pitch of the teeth. The centre wheel thus admits of being polished,
a process which not only improves the appearance, but likewise insures correctness of the work.
The mode of constructing the pattern of a mortise-wheel, differs from the ordinary routine for toothed
patterns in little more than the omission of the teeth. The rim is however made wider than that of a
toothed wheel of the same pitch, by twice the thickness of tooth; and its thickness is double that of
the ordinary toothed rim.
The manner of construction is this: The rim is built and dressed, and has the arms and centre fitted
into it as already described. The dovetails are also fitted into the corresponding grooves in the rim
but these, instead of having teeth fixed upon them, carry simply their pieces to serve as core-prints to
guide the founder in laying in his cores to make the mortises for receiving the tails or tenons of the
teeth. These prints are made in length equal to the breadth of the teeth, and in breadth equal to
their thickness. When the pattern is moulded the prints leave their impressions in the sand, and these
are filled by cores of corresponding size and of a depth equal to the thickness of the rim.
The rim of the casting being carefully faced up, or dressed in the lathe, is ready to be cogged. The
cog-tenons are in the first place fitted tightly into the mortises of the rim; the wheel is then put into
the lathe and the points of the teeth and ends of the tenons are dressed off in precisely the same way
as the wooden teeth of a wheel-pattern the pitch lines of the wheel are then run upon them with a
point, and the curves of the teeth being described, the cogs are ready to be taken out and finished bv
hand; or the wheel may be put into the wheel-cutting machine, and cut to the form and pitch required.
Wooden cogs, it will be seen from the rules already given for the strength of the teeth of wheels,
ought to be thicker than iron teeth in the proportion of the cube of 14 to the cube of 12; the difference
is commonly made greater, and perhaps correctly, as the strain falls principally upon the necks of the
tenons of the teeth. This allows of the iron teeth of the wheel with which the cogs are to geer, to be
dressed to the exact form and thickness, and polished on their acting surfaces, to prevent injurious
abrasion of the wooden cogs. By dressing, the iron teeth are however diminished in strength, and
consequently a pair of wheels of the kind here described ought to be made fully more strong than
wheels of the ordinary kind.
When wheels are beyond a certain size, it becomes necessary to cast them in segments, which are
afterwards united to form the complete wheel. The pattern of the rim of a wheel of this kind consists
of a single segment of which the required number of castings are made. The segment is provided at
the ends with the requisite means of connecting the parts together, and to the arms which are also
commonly cast separately, and bolted to the rim and centre. As the rim in this case may be cast of
any degree of thickness without risk of injury to the wheel, it is commonly made with recesses to re-
ceive the ends of the arms, which are fixed in their places by keys, bolts, or both, according to the mode
of construction preferred by the maker. The segments are also sometimes, and advantageously, dove-
tailed into each other on the inside at the ends, and the arms are fitted also by dovetail-checks and
bolts to the middle of their length. This mode of fitting requires great accuracy of workmanship, but
when well executed it possesses a degree of neatness which cannot be otherwise attained. The arms
are fitted in the same manner to the centre.
Another mode is to cast each segment with an arm attached to the middle of its length, and to fit
these upon the centre in the way described. Thus if the wheel have eight arms, the rim will be com-
posed of eight segments, and the centre will be cast with an equal number of recesses to receive the
ends of the arms.
When the wheels again are of an intermediate size, too large to be cast in one piece, yet not larger
than will admit of their being cast in two parts, they are then cast in halves, each half complete in itself
from the circumference to the centre. These halves are then fitted together to form the complete
wheel. The manner of fitting is various. The common way is to cast each half with strong flanges
throughout the whole diameter, and to bolt these together. Wheels constructed in this way, must of
necessity have an even number of arms, 80 that the division may be effected through the middle of an
arm running through the diameter of the wheel. The two flanges, that is, the flange of each segment,
will form the feather of that arm, but double the thickness of the ordinary feather.
We have seen wheels put together in three pieces in this way very satisfactorily, but the difficulty of
fitting is then very considerably increased. It is also not uncommon to cast the segments with strong
flanges only at the rim and centre, and to trust to these alone to hold the segments of the wheel to-
gether. This greatly reduces the work of fitting, and we do not see that sufficient strength could not
thus be attained.
With respect to the material of the patterns of wheels, it is only necessary to observe that the com-
mon practice of using white pine for the arms and rim, and hard wood for the teeth, and their dovetails,
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is both economical in point of time and expense. But in all cases where the teeth are expected to
require no dressing after leaving the sand, it is of importance that those of the pattern be formed with
the utmost accuracy, and have a smooth surface. And it may be here observed, that unless in the
circumstances referred to, it is not desirable, in point of economy of wear, to dress the teeth, at least to
the extent of removing the cast surface, which is by far the hardiest and most durable part, and after
working some time, it takes likewise a smoother surface than can be given to the softer metal beneath.
The surfaces ought, however, to be cleaned of any imbedded sand, and excrescences which may be found
adhering to them when taken out of the sand; and it is also of advantage to run-up, or clean the points
of the teeth in the lathe when the wheel is small.
The key-seats of the eye are usually cut by the slotting machine, and of a breadth proportioned to the
size of the eye, and not to the pitch or diameter of the wheel.
Shafting is a department of mill-work which embraces some of the most important considerations
within the compass of practical dynamics. If on the one hand shafting be too light, it will be of little
importance that the wheels are accurately made, and proportioned to the power conveyed; the tremor
and hobbling gait to which an overburdened condition of the shaft-geer invariably gives rise, will
speedily destroy their adjustment by irregular wearing of the teeth. The bush-brasses at the same
time suffer, and the evil is aggravated till ultimately a sudden failure at some important point sets the
whole at rest. On the other hand, if the shafting be made too heavy, an unnecessary expense is in-
curred in the construction; and, what is usually of more importance, and in most cases of more serious
consequence, a waste of power is occasioned by the unnecessary friction and wear produced by the
superfluous weight at the journals and footsteps. Both extremes are thus to be avoided with equal care.
One important feature of our modern practice is the higher velocities at which the main shafts are
impelled. By this means the geering can be made lighter for the same power, and therefore more
durable, since the friction and inertia are diminished, and the impulsion thereby rendered more steady
and uniform. The power of the prime mover is therefore economized; and if that power be derived
from steam, a corresponding saving is effected in the maintenance of the engine; and if water power be
employed, a proportionally greater quantity of machinery can be impelled by the same waterfall.
Hence the principles which ought to guide the engineer in the construction of a system of shaft and
wheel geering is, to regulate the connections in such a manner that the inertia of the mass and the
friction of the motion may be reduced to a minimum, and to effect this purpose the velocities and
strength of the parts must be adjusted to one another, and to the speeds of the machines in which the
power is to be expended.
But before entering upon the investigation of the practical bearings of this general principle, it may
be necessary to glance briefly at the various kinds of shafting employed by the millwright and engineer.
As respects material, there is only the choice between wood and iron; and the forms are chiefly cylin-
drical and square, but sometimes octagonal. When large wooden shafts are employed, as they some-
times still are, especially as axles of wooden water-wheels, they are commonly made of one solid log,
with gudgeons inserted into their ends, according to a method to be subsequently described. But the
scarcity of large timber has not unfrequently led to the substitution of shafts built of planks, and these,
when properly made and of sufficient strength, have been found little less durable, and much less expensive.
Iron shafts are of two varieties-forged and cast. Those of large size are commonly of cast-iron,
while smaller shafts and spindles are formed of malleable iron. The form most common to both is that
of a cylindrical solid; but often they are square, sometimes octagonal, and occasionally hexagonal.
Cast-iron shafts are also not unfrequently made with ribs upon their peripheries, and then they are
called feathered shafte-probably from the slight resemblance which they bear to the feathered part of
an arrow. Cylindrical shafts of large size are also sometimes cast tubular, and they are then termed
hollow shafts.
The subjoined figures represent the forms of cross section most commonly adopted in shafts of the
respective materials, iron, malleable and cast, and wood.
a
2080.
Maileable iron, cast-iron, wood.
2081.
Cast-iron.
In respect of these forms, the cylindrical is in general to be preferred, not that it possesses greater
strength, as is commonly supposed, for the same weight of materials, but because it is the simplest and
the most elegant in appearance when mounted. Feathered shafts, as they are commonly made, although
their strength to withstand lateral pressure be augmented by the breadth of the feathers, are very rarely
free of tremor from want of substance between the feathers, and unequal distribution of the material
around their axes. It is, however, an error to assume, with Tredgold and others, that the circle is the
only form of section which gives to the axes the property of offering in every direction the same resist-
ance to flexure; for it might readily be proved geometrically that the square section must offer the
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same resistance to flexure in the direction of its sides and diagonals; and what is true of the square, is
equally true of a great number of other figures which may be formed by combining symmetrically the
circle and square. The hollow cylindrical form admits of being adopted only in shafts of the very
largest class, and for the same weight of material is greatly the strongest form that can be employed,
and the best adapted to resist the combined action of torsion and cross strain. It is difficult to make a
casting of a tubular form below a certain diameter with the necessary accuracy and, therefore, in shafts
of small diameter it is much greater economy to make them solid.
The sections represented above, Figs. 2080 and 2081, must be understood to be those of the body-
parts of the shafts; but the shaft is very seldom uniform throughout its length even when cylindrical,
and never when of any other form; for whatever be the figure of the body-part, the journals must
always have a circular section, and every shaft must-as will be subsequently seen-have at least one
journal or gudgeon on which it revolves. If the shaft be one of a line leading the power to some dis-
tant point from the source of motion, it will likewise have its extremities adapted to couple with the
shafts between which it is placed; and if intended to carry a wheel or belt-pulley, it is commonly pro-
vided with a boss on which the same is keyed. In very large shafts the boss may be replaced by four
snugs projecting from the periphery to receive the keys, and when the shaft is of cast-iron and square,
as shown by the section marked a, the part to receive the wheel takes frequently the form of section
marked b.
The following cut, Fig. 2082, illustrates the usual form of a cylindrical iron shaft, on which a wheel is
to be keyed at the enlarged part b, denominated the wheel-boss, and which is to be coupled to another
shaft at the part c, by what is termed a half-lap coupling, to be afterwards described. The journal is
marked a, and has the same diameter as the body-part of the shaft marked d.
2082.
b
d
In ordinary shafting, the gudgeons are now always formed of the same piece as the shaft, and turned.
But in ordinary water-wheels the axles are formed of cast-iron, usually hollow, with independent gud-
geons fitted into their extremities; and when made of wood, the gudgeons must of necessity be inserted.
The drawings in Fig. 2083 show the general form of a hollow cast-iron axle for a water-wheel, with
two modes of fitting the gudgeons. The form of gudgeon fitted into the end marked A is peculiarly
adapted to axles of this kind, on account of its simplicity. The metal of the shaft is here thickened
2083.
B
B
c
A
internally to a distance equal to the interior diameter, and three ribs cast in it have key-seats cut in
their faces. The gudgeon marked a has three arms cast or forged upon it, (according as it is made of
cast or wrought iron,) of the same length as the ribs on the interior of the shaft; and these being dressed
in the lathe at the same time that the gudgeon is turned, are correspondingly key-seated. A wrought-
iron hoop being driven red-hot upon the end of the shaft to prevent it from splitting, the arms of the
gudgeon are adjusted in their places and keyed tight, the keys having as little taper as can conveniently
be allowed for fitting. They are thus less likely to become loose in their seats.
Sometimes the gudgeon is provided with four arms, but it is commonly admitted that the mode de-
scribed is preferable, because with three arms the keys must all bear equally, whereas when four are
employed it is difficult to obtain a uniform tightness of the set.
The form of gudgeon shown at B is more applicable to a vertical than to a horizontal shaft, although
employed indifferently with both. The shaft is in this case cast with a projecting flange round its ex-
tremity, of the same diameter as a similar flange cast upon the gudgeon. The interior of the end of the
shaft is, in the first place, bored out truly cylindrical, and the flange is at the same time faced. The
flange of the gudgeon is likewise faced, and a piece cast on the back of it is turned to fit into the turned
part of the end of the shaft; the two flanges are then brought together and secured in tight metallic
contact by bolts and nuts.
In this form of gudgeon the pivot is sometimes formed of wrought-iron or steel, and fitted into the
flange and socket, which must of necessity be cast. This allows of the pivot part being replaced when
worn out, at less expense than if the whole consisted of one piece.
To render this a good and lasting arrangement, it would be necessary to make the socket of the
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gudgeon of considerable length, and to bind the two flanges together by a hoop of malleable iron, em-
bracing both their circumferences, and put on red-hot.
When the shafts are of small diameter these contrivances are not usually employed; the part of the
gudgeon which enters the shaft is formed as a solid cylinder, in the surface of which the key-seats are
formed; the cylinder fits loosely into the end of the shaft, and is made tight by the keys, as in the first
method described. The shaft, with its gudgeons fitted, is then put into the lathe, and the pivots are
turned truly concentric with the body-part, and of the strength desired, the original diameters being
usually much greater to allow for any inaccuracy in the fitting. This is also sometimes practised with
shafts of the larger class; but more commonly the gudgeon part alone is dressed in the lathe, and the
adjustment intrusted to the fitter, who can adapt his keys to obviate any small inequalities due to
the casting.
The form of gudgeon most approved of for wooden water-wheel axles is that known as the cross-tail
gudgeon, which consists of a pivot piece projecting from the centre of a cross, roughly represented by
F in side elevation, and by + on end. The vertical pieces forming the tails are let into mortises cut
in the end of the shaft, and the pivot coinciding with the axis of the shaft, the mortises are filled up on
each side of the neck by pieces of wood. A strong malleable-iron hoop is then wedged tightly on the
end of the shaft, in order to fasten and retain the pivot of the gudgeon in its parallel position.
This gudgeon has also been made with only two cross-tails; and in well-finished work the tails,
whether two or four, pass within a malleable-iron ring, which embraces the shaft at the point where
they project to the circumference of the shaft: this ring being made slightly less in diameter when cold,
is fitted in its place at a temperature of red heat, and contracting, embraces the tails and shaft tightly.
The second ring at the end is made of full size, and fixed by wedges. As an additional security, the
arms of the cross are sometimes fixed by screws, which pass through into the wood of the shaft. The
arms are in this case made thicker, and do not enter 80 far into the shaft. The screws by which they
are fastened are made of considerable length, and the distance being noted to which they will pass into
the timber, mortises are cut at these points large enough to receive nuts suitable to the bolts. The nuts
being dropped into their places, opposite to the screwed ends of the bolts, they are screwed up by a
spanner, and thereby hold the arms tightly in their place.
By these and similar means the gudgeon can be made for a time quite fast; but when it is consid-
ered that the direction of the stress which tends to loosen it is continually changing, and that such stress
being exerted on wood, a material which is comparatively very easy and permanently compressed, it is
not difficult to perceive that the fastening of gudgeons must have been a matter of much importance to
the older millwrights, and that with all their care and ingenuity they seldom succeeded in rendering
them firm and lasting. Accordingly several modifications of the schemes described have from time to
time been resorted to with indifferent success. The best of these is undoubtedly that of Robert
Hughes, described in the Transactions of the Society of Arts, (vol. xxxi. p. 223.) It consists in casting
the gudgeon with cross-arms, which fit into notches in an octangular box of cast-iron which has been
previously fixed on the end of the shaft." The contrivance is represented by Figs. 2084 and 2085, in
which A represents (in section) a portion
of the end of a wooden shaft of an octangu-
2085.
2084.
lar form; it is long enough to reach across
the pit in which the water-wheel works, and,
a
B
having a gudgeon at each end, is supported
a
b
b
and revolves upon them in proper bearings.
B B is the cast-iron box accurately fitted on
d
the end of the shaft, and being wedged tight,
C
C
C
prevents the wood from splitting as effectu-
d
ally as any hoops can do. Upon the end of
the box is a projecting flange a a, with four
a
b
b
B
notches to receive the cross-arms bb, dd of
a
the gudgeon C. This cross is firmly attached
to the box by four screw-bolts, which pass
through the flange and the ends of the cross-arms. The figure in section (in which the cross and box
are represented separately to show more clearly the mode of putting them together) explains a further
precaution which is necessary for strength; and which consists in the inside face of the cross having
projections ee, which enter the end of the box, and keep the pivot truly in the centre, and prevent any
lateral strain on the bolts, which have thus merely to hold the gudgeon fast to the end of the box.
When a gudgeou, fitted according to this method, becomes worn out so as to require replacement, it
can be removed by taking off the four nuts, and a new one applied; the gudgeon also being of small
dimensions, the cylindrical part admits of being conveniently turned in a lathe, which is a considerable
advantage."
This gudgeon involves nevertheless a considerable deal of workmanship, and the real practical advan-
tage which it possesses over the common cross-tail gudgeon is simply, that it does not require the end
of the shaft to be impaired by mortising, and affords the means of renewing the gudgeon when the pivot
becomes worn out, with more facility and without injury to the shaft.
The stress to which water-wheel gudgeons are subject is generally of a lateral and simple character.
The gudgeons have manifestly all the weight of the shaft, wheel, and sometimes the water, to sustain,
and ought, therefore, to be made sufficiently strong for that purpose; but they ought obviously to be as
little as possible increased in diameter beyond the required strength, and a proper allowance for wear
to insure durability.
In practice it is common to make the length of the gudgeon equal to the diameter. Establishing this
as a principle, from experiments on the strength of iron, we deduce the following practical rules:-
Find the weight in pounds to be supported by each gudgeon, extract the square root of the
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number. and that root divided by 25 when the gudgeon is cast-iron, and by 26 when it is wrought-
iron, will give the diameter and length of the gudgeon from the shoulder to the extremity expressed in
inches.
Example.-The gross weight on the gudgeons of a water-wheel is 86,800 lbs. ; required their diameter,
the gudgeons being cast-iron ! The gross weight being 86,800 lbs., that upon each gudgeon will be
43,400 lbs., and 43400 = 20832667, which divided by 25 gives 8.3336 inches for the diameter of the
gudgeon. The actual diameter of the gudgeons is in this case 8.5 inches, and they have worked in
cast-iron bearings for upwards of twelve years, the bushes being only once and lately renewed during
that period.
With respect to the strength of shafts generally, there are different circumstances to be considered in
the calculation. It frequently happens, in examining the conditions under which the shaft is to be
placed, even when the stress is manifestly compounded of lateral pressure and torsion, that one of these
may be neglected in the calculation of the strength. Thus the effect of lateral pressure is to produce
deflection, which must be provided against, and ought not to exceed 100 th of an inch in one foot of
length; if, therefore, the dimension requisite to give this degree of transverse stiffness be greater than is
required for the twisting power brought on at the circumference, this latter strain may obviously be dis-
regarded; and conversely, when the torsion is great and the lateral pressure insignificant, as in the case
of vertical shafts, the effect of the former only requires to be considered. And again, when the shafts
are long, and have the power and resistance acting at their extremities, it is not enough that the body
part of the shaft be sufficiently stiff to prevent deflection beyond the proper limit; it must have
sufficient dimensions to prevent twisting beyond a certain quantity; and in estimating the effect of
torsion, it is not so much the shaft itself which ought to be considered as the journal, which is constantly
exposed to wear, and which is thereby rendered more liable to rupture.
In examining successively the amount and effect of these species of stress, and the circumstances
under which their intensity is developed separately and in combination, the first part of the inquiry
which naturally claims attention is the degree of strength requisite to withstand lateral stress. In this
inquiry it is not the ultimate transverse strength, but the stitfness of the shaft which claims attention
in other words, the resistance which the material offers to bending by its own and any superadded
pressure tending to deflect it from the straight line. Now, the shaft being square, if
d = the depth or side of the square in inches,
L = the length of the shaft in feet,
W = the weight or pressure upon it in lbs.,
δ = the deflection at the middle of the shaft in inches,
M = the modules of elasticity then
1°. When the shaft is supported at both ends, and the stress is intermediate,
= M or d= 432 δ }
That is, in words-Multiply the weight upon the shaft in lbs. by the cube of the length expressed in
feet, and by 432, and divide the product by the value of M, multiplied by the assumed amount of
deflection s to be allowed: the fourth root will express in inches the depth of the side of the shaft when
the transverse section is square. Or the square root will express the area in square inches of the cross
section when the shaft has any other form.
This rule answers for any material of which the weight of the modulus of elasticity M is known. In
its general form it is, however, laborious, from the magnitude of the numerical quantities involved fixing
upon particular values of M for the different materials to be employed, and also fixing the maximum
value of d, it may be greatly simplified. In shafting, as already remarked, the deflection should not
exceed 100 th of an inch for every foot of length; hence,
L For wood-Taking M generally 1,500,000 lbs. and s = 100 L inches.
Then for square shafts, d being the depth of the side of the square in inches,
(A)
And for round shafts, d being the diameter in inches,
(B)
IL For cast-iron.-Taking M 18,000,000 lbs. and δ = 100 L inches.
When the section is square, d being the depth of side,
(C)
When the section is round, d being the diameter,
d'= 240
(D)
240
III. For wrought-iron-Taking :24,500,000 lbs. and δ 8=100 = 100 L inches as before.
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When the section is square and d the side,
(E)
When the section is round and d the diameter,
(F)
2°.-If the stress be uniformly distributed over the length of a square shaft it will produce the same
deflection of the shaft in the middle as #ths of that weight applied at that point. And if W be the
weight of the shaft itself, and it be otherwise unloaded, the deflection produced by its own weight
will be,
L-For cast-iron shafts when square,
25000
(G)
And when the shaft is cylindrical and solid,
150000 d
(H)
IL-In wrought-iron shafts when square,
336000
(I)
And when the shaft is cylindrical and solid,
198000
(J)
As an example of the application of these rules, let it be required to determine the deflection at the
middle of the length of a 8 inch wrought-iron round shaft of 15 feet length betwixt its bearings:
Here L = 15, and therefore L⁴=50625,
3, and therefore d=9;
Hence, δ = 198000 1782000 50625 03157 inch.
The converse of this case frequently occurs; that is, having determined the diameter of the shaft,
and assumed a maximum amount of deflection to be allowed, what may be the distance between the
bearings 1
Let the maximum deflection be 100 th of an inch for every foot of length, that is, 8=1/00 = inches on
the whole length; then from equation,
(G)
L = 2560
(K)
(H)
L = 1500
(L)
(I)
L = 3360
(M)
(J)
L = 1980
(N)
Thus, let the diameter d = 3 inches, as in the last example, the shaft being of wrought-iron and a solid
cylinder; then from equation (N) we have
L= V 1980 x 9 = 2619 feet
the distance between the bearings, on the condition that the deflection of the shaft by its own weight
shall not exceed Tooth of an inch for each foot of the length. This being 26 feet in all, the deflection
at the middle will be 26=1 inch nearly, which is a safe allowance, in ordinary cases, on this length
of shaft.
Again, if the torsion be very small, and it be more convenient, and possibly more economical, to
adjust the diameter of the shaft to the limit of deflection than the length of the shaft, this being fixed,
then, assuming the value of s as before, we obtain from equation
L'
(K)
=
2560
~
(0)
L'
(L)
d =
~
(P)
1500
L'
(M)
d
=
(Q)
3360
L'
(N)
d
=
(R)
1980
Thus, the length between the bearings being 30 feet, what ought to be the size of a cast-iron square
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shaft in which the deflection shall not exceed 30 X -01 = ·3 inch at the middle of the length 1 In this
case the rule is equation, (0,) whence,
d = 2560 30" = 3-2542 inches,
the side of the square, the area of the cross section of the shaft being 1059 square inches.
The distances between the bearings given in these examples are not, however, such as would be
adopted in practice; but simply show the limits in reference to the deflection of the shaft by its own
weight. The spring to which a shaft is always liable in working, from irregularities in the power and
resistance, even when its deflection is far within the limit prescribed, renders bearers in general not
more than 10 feet apart necessary to prevent vibration; these are usually of a less substantial charac-
ter than those in the immediate vicinity of the working points.
III. It is sometimes found unavoidably necessary in a system of geering to overhang a wheel or belt
pulley, leaving only one end of the shaft supported, while the stress falls upon the other. The equa-
tion for the stiffness within the elastic limit is in this case,
6912
When L = the length of the shaft from the point of pressure to the bearing expressed in feet, and M
the weight of the modulus in lbs., d and δ have the same values as before.
Now, in cast-iron, the value of M was before assumed = 18,000,000 lbs.; therefore, when the shaft
is cylindrical, (the only case which it is necessary to consider) we shall have
(S)
When s 100 inches. This equation determines the least diameter of the journal, which is never
greater than that of the shaft.
Again, the value of M for wrought-iron is 24,500,000 lbs.; hence, for round shafts of that material,
II
(T)
2085
When s 100 L inches as before.
As an example of this case, let it be required to determine the diameter of the journal of a mallea-
ble iron shaft on which a belt pulley is overhung, at a distance of 21 feet from the journal ! Let the
weight of the pulley be 180 lbs. and the tension of the belt, when driving, 320 lbs.
Here L = 2.5 feet, and W = (180 + 320) lbs. = 500 lbs.
Hence, d' = 21 500 = 14881,
And d = = 12.21 = 3-49 inches, the diameter required.
In this equation it is presumed that no flexure of the shaft takes place beyond the journal, and, to
fulfil that condition-which is necessary to save the bearing, and avoid undue friction-the shaft must
either be made very strong or have only a short distance between the first and second bearings. Thus,
suppose a pulley overhung on the shaft, to prevent the shaft from springing between the proper bear-
ings, an intermediate bearing is placed at a short distance behind the bearing nearest the pulley, which
prevents upward flexure, and thereby saves the pillows adjoining the stress. It may also be here ob-
served that the distance between the bearings which our rules seem to allow are greater than is com-
monly practised in modern mill-work; steadiness of motion is much desired, and, as friction is not
increased by the number of bearings, provided these be properly made and fixed, it is reckoned good
economy rather to multiply the bearings than to risk even the small amount of deflection which we
have taken as a safe limit.
We have hitherto referred only to two forms of shafts-square and round and these solid. But the
same rules may be considered to apply generally to any other forms of solid section ; for knowing the
side of a square shaft of a given strength, the cross sectional area of any shaft of equivalent strength is
thereby approximately determined, however different in form.
Mr. Tredgold's rule for the strength of hollow shafts within the elastic limit, the cylinder being sup-
ported at the ends, is
WL
and is thus expressed verbally Fix on some proportion between the diameters; let the external diam-
eter be to the internal as 1 is to N; the number N will always be a decimal, and ought not to ex-
ceed 0.8." Then multiply the length L in feet by the weight W to be supported in lbs. Also, multi-
ply 500 by the difference between 1 and the fourth power of N, and divide the product of the length
and the weight by the last product, and the cube root of the quotient will be the exterior diameter d
of the shaft in inches. The interior diameter will be the number N multiplied by the exterior diameter,
and half the difference of the diameters will be the thickness of metal
As an example of the application of this rule, let it be required to find the dimensions of a hollow
shaft for a water-wheel, which, including the weight of the water in the buckets, weighs 44,800 lbs.
the whole length of the shaft is 8 feet, from which, deducting 5 feet, the width of the wheel, leaves 3
feet for the length of the bearing: required the exterior and interior diameters of the shaft!
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Making N=7, its fourth power is 2401; and = Therefore, we have by the rule,
44,800
500
X
X -76 3 = 354 in the nearest whole number; and the cube root of 354 is 7, the exterior diameter
n inches; and 7 inches X 7=49 inches, the interior diameter.
When the shaft is supported at the ends, and the stress is not in the middle of the length, but at
distances p and q from the respective ends, the rule becomes,
Thus, let the weight of a wheel and other pressure on the shaft be 36,000 lbs. = W; the distance of
the point of stress from the bearing at one end being 8 feet = and the distance from the other bear-
ing 1.5 foot = and let N = required the exterior and interior diameters of the shaft
The fourth power of 8 is 409; and 1 = 591. Therefore, by the rule
4 X 86,000 X 3 X 15
500
45
and the cube root of 485 is 786 = the exterior diameter in inches; and 7.86 inches X 8 = 6.3
inches, the interior diameter. These rules give the strength of hollow shafts within the elastic limit,
but when the deflection is restricted to a given amount, the diameter must be determined from the rule
diameter of solid shaft =D;
the diameter of a hollow shaft of the same stiffness as the shaft of diameter d.
The second species of stress to which shafts are liable is torsion. The question of torsion divides
itself into two cases as applied to shafts; for, if the shaft be very short, the amount of twist will only
be limited by the ultimate strength of the material, but in ranges of shafting of considerable length,
the angle of torsion must necessarily be confined within certain limits, depending upon the degree of
accuracy of motion, requisite in the particular instance. In the first case it is usually the strength of
journal which is to be determined, for the journal being of sufficient diameter to resist the force applied
to it tangentially, the body part of the shaft will be in no danger of rupture from that cause, since it
has at least equal strength, and is not subject to wear; and, moreover, the ultimate strength must ob-
viously, as respects torsion, be independent of the length-provided, indeed, the length be not less than
the diameter of the shaft. For shafts of which the lengths are small, and in which the angle of torsion
may consequently be neglected, we have the following rules:
I. For solid shafts to resist torsion-Equations (S) and (T). Find the pressure in lbs. acting upon
the shaft at the circumference of the wheel or pulley receiving or transmitting the power: multiply
that pressure by the radius of the wheel or pulley, that is, by the leverage at which it acts; if the shaft
be cast-iron, divide that product by 125, but, if malleable iron, divide it by 140; and extract the cube
root of the quotient; this root expresses in inches the diameter of shaft corresponding to the given
pressure and leverage.
II. For hollow cast-iron shafts, the thickness of metal being 1-5th of the diameter-Equation (W).
Find, as before, the product of the pressure and leverage: divide that product by 109, and take the
cube root of the quotient as the required diameter in inches.
For particular cases in which a different thickness of metal is employed, the equation, of which the
rule is only another form of expression, must be reduced to find the proper divisor. Thus, supposing
the thickness of metal to be fixed at 1-7th of the diameter, then
-
therefore, 125
which must be taken as the divisor instead of 109 when the thickness of metal is reduced from 1-5th
to 1-7th of the diameter of the shaft.
These rules are necessary and sufficient to determine the strength of short shafts to resist twisting,
and, consequently, ought to be employed in calculating the strength of journals; but in shafts of great
length in comparison with their diameters the angle of torsion becomes an important element in the
investigation.
Now, if the extension which the material will bear by twisting without injury when the length is
taken as unity be assumed,
For cast-iron 1200 1
For wrought-iron 1400 1
then the value of 0 in our fundamental equation, that is, the angle of torsion, will be,
2284
L
For
cast-iron
1000
d
For wrought-iron 1965 1000 d L
in which L is the length of the shaft in feet; d the diameter in inches; and 0 the angle of torsion in
degrees of a circle.
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GEERING.
The rule, moreover, indicates the condition that the angle of torsion is as the length directly, and the
diameter inversely; and may, therefore, be adjusted with precision to the degree of accuracy with
which the motion of the first mover must be transmitted.
Taking the modulus of elasticity of the two varieties of iron at the same values as before, our funda-
mental rule becomes, for round shafts of
LRW
cast-iron and solid =
53.5
(S)
LRW
"
and
hollow
53.5
LRW
wrought-iron and solid =
71.3 0
(T)
LRW
"
and
hollow
The data usually attainable in practice are the power which the shaft is required to transmit, the lever-
age at which the power acts, and the length of the shaft; it then remains to fix the degree of torsion
which may be permitted without injuriously affecting the regularity of the motion: these quantities
being settled, the rules expressed by (S) and (T) for solid cylindrical shafts are thus applied:
Multiply the power in lbs. by the leverage at which it acts, and by the length of the shaft, both in
feet; divide the product obtained by 535 or 71.3 times the number of degrees in the angle of torsion
allowed, according as the shaft is of cast or wrought iron; and the fourth root of the quotient will be
the diameter of the shaft in inches.
Thus, by a line of shafting of 40 feet length, the power transmitted is 500 lbs. acting at the circum-
ference of pulleys of 1 foot radius: required the diameter so that the angle of torsion shall not exceed
2 degrees at the extremity, the shafts being wrought-iron
Here 500 X 40 X = 20000
and
713
X
}
20000
then
II
140-25.
142.6
And the fourth root of 14025 is 3:44, so that the shafting would be made 31 inches diameter-which
is the actual case.
The rule for hollow shafts differs from that given only in this, that the thickness of metal in relation
to the diameter must be assigned as before explained; and for square shafts, the rule differs only in
having different coefficients of the angle of torsion.
These rules are sufficient to meet all the cases of calculation which occur in practice relative to the
strength of shafts; but the mode of expression often causes considerable previous computation to
determine the value of the power transmitted in lbs., as here required. The more common and conve-
nient mode is, therefore, to estimate the strength and sizes of the shafting by the horse-power trans-
mitted, and the velocity. According to this measure, from what has already been explained in respect
of velocity, it will be perceived that the resistance must be estimated as the horse-power directly, and
as the number of revolutions inversely, since, with a given power, the velocity must be greater, as the
resistance is less. Thus, the resistance due to 32 horse-power on a journal making 50 revolutions
per minute will strain it to the same, and only to the same extent, as the resistance due to 16
horse-power acting on a journal which makes only 25 revolutions in the same unit of time; for
32
16
50 = 25 And, in all cases, when the horse-power, divided by the velocity, gives the same quo-
tient, the stress is the same.
If the rule contained in equation (S) for cast-iron shafts be reduced to the notation corresponding to
the dynamical unit of power, it assumes the form,
25.5
(U)
in which H represents the number of horse-power transmitted by the shaft, and n the number of turns
which it makes in a minute; L and Θ are respectively the length and angle of torsion expressed in feet
and degrees as before. From the rule in equation (T) for wrought-iron shafts we have the form,
(VC)
These rules will apply to the ordinary kinds of shafting, and where it is necessary to keep the amount
of torsion in view but, in cases where less exactness is required, the simpler rules furnished by
Robertson Buchanan may be adopted. These rules are intended to comprehend three classes, as-1st.
Steam-engine fly-wheel shafts; 2d. Shafts in immediate connection with water-wheels; and 3d. Shafts
for ordinary internal mill-geering. The following are the rules:
3
1st
class
d
=
X
400
-
3
H
2d class
d
II
X
200
H
3d class
d
3
II
X 100
These rules are stated to be derived from "observation of shafts in actual use, and of acknowledged
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good proportions; and for short shafts, they express pretty nearly the practice of some of our best
millwrights; but, in his last edition of the Essays on Mill-work, the rule for cylindrical cast-iron shafts is
=
X
240
Couplings.-Couplings are of necessity employed in a line of shafting when of greater length than is
found practicable to cast or forge in one continued shaft. They are also frequently required in cases where
one length of the shaft would suffice, for the purpose of occasionally disconnecting parts of the geering
beyond a certain point of the line; and likewise for connecting and disconnecting particular machines.
The most simple species of connection is the square coupling. In this the end of the shafts to be
connected are made square, and are embraced by a square coupling-box, the internal surface of which
is fitted exactly to the squares of the shafts. A box is divided into two parts, which close together
diagonally upon the shaft, and are provided with flanges at their junction, by means of which they are
bolted together, and to secure the shafts, 80 that one cannot turn without driving the other. The
coupling is sometimes made quite plain; embracing the shafts like the one now described and, when
occasion requires it, the box may be slipped back on one shaft, to leave it clear of the other, thereby
admitting of the motion being discontinued, or of one or both being removed for repairs or alterations.
An objection to this arrangement of a rigid square coupling at once suggests itself, when we reflect
that, although the motion would go on all very smoothly so long as the shafts remained mathemati-
cally true to each other, when the one of them wears down in its bearings faster than the other, or
when the wearing is in different directions, it must follow, that in some part of the revolution the shaft
is lifted off its bearings, where there are two bearings, one on each side, and unsteady motion is pro-
duced, together with further straining and wearing of the couplings. This objection, it is true, applies
principally to the shafts of heavy mill-work; but it is only for such purposes almost exclusively that
this form of coupling is employed; in small machinery it is only occasionally employed.
A variety of the square coupling consists in having fitting-strips, or projections along the corners of
the square parts of the shafts. The square form of the shaft is in this case virtually preserved, and
there is the advantage of the coupling being fitted with greater facility, while the strain is concentrated
upon the corners of the shaft.
The round coupling is, in some respects, open to the same objections as the square coupling. It will
be understood from Fig. 2086, which represents it in section. In this the ends of the shafts are made
cylindrical, and meet together, with flat
ends, under a round coupling fitted truly
upon them, and secured to them by pins
2086.
a and b at right angles to one another.
This joint may be made with greater pre-
cision and much less expensively than the
b
other, as the parts may all be accurately
turned and fitted together. It is clear,
however, that, as the strain is concen-
trated on the pins and holes, these parts
must wear out soon; at the same time,
it is easy to renew the pins, though, obviously, they cannot be made to fit the holes so accurately as
they did at first. This coupling is not often used for heavy shafting, on account of the objection just
stated, though we think it might readily be applied to lighter shafts.
The half-lap joint, represented in Fig. 2087, affords a neat and compact method of coupling. The
shafts, being cylindrical at the ends,
are formed with semi-cylindrical ex-
2087.
tremities, and fitted together 80 that
the tongue of the one fits into the
recess of the other; the cylindrical
form is thereby completed, and the
joint is covered with a thimble or ring
secured to it by a key.
This species of coupling is formed
partly by turning and partly by plan-
ing. The coupling bosses are first turned with great accuracy; they are next planed on their flat
surfaces to an exact semi-cylindrical form. The coupling-box being turned externally, and bored out
to a gage, is fitted upon them by adjustment of the flat faces of the laps with the file; the key-seats
are then cut, and the key fitted, when the operation is complete. The operations are thus attended
with considerable expense; but the accuracy and durability, and likewise the elegance of the coupling,
fully compensate for the labor bestowed on its original construction.
For convenience of disengaging the connection, the boss of the shaft nearest the prime mover is pro-
vided with a thin ruff, to which the coupling-box is driven up, and which prevents it from passing off
in that direction; the adjacent boss of the other shaft is left plain, and from this end the key is driven.
To disengage the coupling. the key is driven back by a drift passing over the ruff, above which the
end of the key rises in thickness; the box is then driven back in the same direction, that is, towards
the left in the figure, and relieves the laps. The shaft thus disengaged, when lifted out of contact
with the tongue of the other, will cease to be impelled, and consequently the motion of all the geering
behind that point will be discontinued.
The coupling shown in Figs. 2088 and 2089 is constructed of two cast-iron plates, a a and bb, keyed
one on the end of each of the shafts. The plate a is formed with two segmental openings in it, which
will be better understood from Fig. 2089 at cc; these openings are intended to receive corresponding
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projections on the face of the plate b, as represented in the section; and thus the shafts become
engaged. The rim of the plate a over-
a
laps and embraces the circumference
of the other plate, and thus they are
preserved exactly concentric.
b
b
This coupling, applicable to shafts
with two bearings, one on each side of
2088.
the coupling, is simple and durable.
It is easly adjusted, and may be dis-
connected without difficulty.
Fig. 2090 is another combination of
disks suitable for couplings with only
one bearing. The disk b is keyed on
one shaft, and is recessed on the face,
to receive the smaller disk c; this disk
is sunk flush with the face of the other,
and is screwed tightly up to it by
b
b
means of the ring a, which is bolted
to the disk b, and secures that marked
c. Between the three plates, a, b, and
a
c, annular pieces of leather are interposed, which bring them all to a proper bearing.
This combination, termed a friction coupling, is useful for preventing breakage of the connections in
case of a sudden stoppage or reversal of the motion. It
is plain that the holding power of the coupling depends
2089.
simply upon the tightness with which the disks are screwed
together, and the consequent frictional force of the surfaces
C
of leather and metal.
Of late years, in this country, turned wrought-iron shafts
have been very generally adopted in manufactories and
workshops: the coupling in most common use for connection
is the faced coupling, Figs. 2091 and 2092. This coupling
a
consists of two parts, one of which being firmly keyed to
a
the end of each of the shafts to be connected, the faces are
then brought together, and securely united by bolts. In
fitting this coupling, considerable care is requisite. Each
part of the coupling is first turned and drilled, then driven
hot on to its shaft, reduced a little in diameter to receive
c
it, or forced on by screws. It is then strongly secured by
a key or keys to the shaft. The shaft is now put into a
lathe, and the coupling is faced ; that is, the faces of the
coupling which are to be bolted together are turned, so that they are perfect planes, at right angles
to the shaft. The bolt-holes on the two portions should correspond exactly. They are therefore drilled
on a chuck, with an index; the holes are made slightly tapering, and the bolts, fitting tightly, are
driven in by smart blows of a hammer, and secured by nuts. Faced couplings, thus fitted, afford com-
2090.
2091.
a
b
2092.
a
0
b
plete and firm connections. The chief objection to their employment lies in their stiffness or rigidity.
They are, therefore, mostly used to connect wrought-iron shafts, when the elasticity of the shafts
obviates the inconveniences resulting from little, and sometimes unavoidable, settlements or inequalities
of the bearings.
Another form of permanent coupling is that known as Hooke's Universal Joint, from the name of
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the inventor, Dr. Robert Hooke. The object of this coupling is to unite shafts which are inclined
to each other in the line of direction, and which do not, therefore, admit of being rigidly con-
nected, as in ordinary cases. This coupling is very commonly employed in light machinery, as in
steeple clocks, for taking off the index-motion, and is then usually constructed by forming an are
on the two extremities which it is intended to connect, and to form the joint by a central cross 6+3;
the extremities of the ark on the end of
2093.
one shaft being jointed to the arms a a,
4
and the extremities of the arc on the other
shaft on the arms b b, at right angles to
the former. But this simple mode of con
struction is not adequate to the purposes
for which the coupling is required in a
line of shaft-geering; in this case, al-
though the principle is not in any way
changed, the construction is much more
substantial. Figs. 2093 and 2094 rep-
resent a form of it adapted to heavy
strains. A is a strong disk keyed on the
end of each shaft carrying a pair of
2094.
bearings for the reception of the gud-
geons formed on the extremities of the
cross. Fig. 2094 is a face view of one
of the disks, showing the cross in its
place, with its alternate journals disen-
gaged.
In this illustration the shafts are
shown at nearly the limit of the angle
to which the single joint ought to be
applied. This angle ought not exceed
fifteen degrees when a higher angle
is introduced, the rotatory motion be-
comes very sensibly irregular, and the
friction is greatly increased. This defect may be obviated by using a double joint.
With the view of admitting the disengagement of the connection, in cases of sudden steppage or
reversal, the coupling, Fig. 2095, is sometimes employed. In this instance, the shaft is supposed to be
continuous, and the coupling may be termed
a disengaging coupling ; a and b are the two
parts of the coupling, formed on the acting
faces into alternate projections and recesses,
such as they correspond with, and exactly fit
into each other when in geer. The part a is,
2095.
in this example, cast on a spur-wheel, from
a
which the motion of the shaft is supposed to
be taken off. Both of the parts a and b are,
to a certain extent, loose on the shaft; the
b
former being capable of moving round on it,
c
€0
though deprived of longitudinal motion by
washers and pins marked e. and the latter
being free to slide on the shaft, though pre-
vented from turning on it by a sunk key,
which slides in a slit inside the clutch or slid-
a
ing piece b. The mechanism is put into geer
by means of the handle d, which terminates
in a fork with cylindrical extremities c, and
it is obvious, that by the contact of the flat
faces of a and b, the latter will immediately
carry with it the other part at the same speed
as the shaft. Supposing, now, that the mo-
tion of the wheel a is suddenly accelerated, the oblique faces of the couplings immediately fall out of
contact, and slide free of each other, leaving the couplings clear, and the shaft free to continue in
motion.
In the old form of this contrivance, known as the sliding bayonet clutch, the part b, instead of the
tooth-like projections on the face, had two or more prongs which laid hold of corresponding snugs cast
on the face of the part a-which, moreover, was usually a broad belt pulley introduced with a view to
modify the shock on the geering on throwing the clutch into action. In an older form still the pulley
was made to slide end-long on the shaft. A form analogous to this was known as the "lock pulley."
Instead of the end-long motion common to the other modes, the parts were "locked" together by a bolt
fixed upon the side of the pulley, and which, when shifted towards the axis, engaged with an arm of a
cross, of which the part b, in Fig. 2095, is the modern representative. The bolt was wrought by means
of a key and stop, the turning of the key throwing back the bolt, and thereby unlocking and disengaging
the pulley.
The form of coupling represented by Fig. 2095 is particularly applicable when the impelling power
107
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850
GEERING.
is derived from two sources-a circumstance which frequently occurs in localities affording water power
to some extent, and yet not in sufficient abundance for the demands of the work. The deficiency is
usually supplied by a steam-engine; and the two powers are concentrated in the main line of shafting
by a coupling of the kind depicted. In cases of this kind, the speed of the shafting being fixed, and the
supply of water inconstant, the power of the water-wheel ought to be thrown upon the wheel a a, and
that of the engine upon the shaft at another point. By this arrangement, the speed of the line can be
exactly regulated by working the engine to a greater or less power, according to the supply of water.
The proper speed of the water-wheel will likewise be maintained, which is of importance in economizing
the water power.
The same form of coupling is also used occasionally for engaging and disengaging portions of the
machinery. But for this purpose the object is to obtain a mode of connection by which the motion may
be commenced without shock; for it is a law in mechanics that when a body is struck by another in
motion, some time elapses before it is diffused from the point struck through the other parts; conse-
quently, if the parts receiving the blow have not sufficient elasticity and cohesive force to absorb the
whole momentum of the striking body till the motion be transmitted to the centre of rotation, fracture
of the body struck must necessarily ensue. Hence, in a system of mechanism, any parts intended to
be acted upon suddenly by others in full motion ought not only to be strong, but they ought to be ca-
pable of yielding on the first impulse of the impelling force with as little resistance as possible, and
gradually bring the whole weight into motion. The common mode of driving by belts and pulleys
accomplishes this object very satisfactorily. In this the elasticity of the belt comes into action; and
should this be inadequate, it has the liberty of slipping on the pulleys, till, by the friction between the
sliding surfaces, the belt gradually brings the quiescent pulley into full motion. This mode of connection
is unexceptionable when the power to be transferred is not great; but its application to large machinery
is attended with inconvenience.
When the belt connection is employed, the provision of the fast and loose pulley is the most simple
and effective form yet devised for the purpose. It consists simply of two pulleys in juxtaposition on
the same axis-the one fast, and the other loose, 80 that the belt which transmits the motion may be
shifted at pleasure upon one pulley or the other, by that means putting in or out of motion the axis
upon which they are placed. The driving pulley-that is, the pulley on the shaft from which the mo-
tion is derived-ought to be equal in breadth to the two on the second shaft; and these last ought to
have their rims slightly rounded or swelled in the middle to prevent the belt slipping off-which it is
apt to do when the rims of the pulleys are flat. This curious property is of great practical importance,
and has obviated all those clumsy appendages formerly required to keep the belt from being thrown.
This mode of driving is not, however, always convenient; and, accordingly, many attempts have been
made to accomplish the same with wheels. Perhaps the best of these is the method of friction cones,
a
2096.
d
b
b
represented in Fig. 2096. The two parts of this coupling, c and d, are arranged on the shaft b, in the
same manner as we have described under the preceding figure. a is a shaft driven by means of bevel-
geer off the main shaft b, its motion being derived from the latter shaft through the coupling. c is an
interior cone cast upon the back of the bevel-wheel; d is an exterior cone having the same taper as the
cone c, such that by means of the handle e it may be moved into contact with the interior cone. The
surfaces being supposed to be well fitted to each other, the cone d will, by its friction, drive the cone c,
and thereby also the upright shaft. When either of the shafts a or b is accidentally stopped, the cones
immediately fall out of geer, and the connection is broken. They are held in geer by means of a screw,
or more commonly, and perhaps better, by a weight.
This coupling works very well, if properly adjusted at first; but requires some nicety in communi-
cating the exact degree of taper to the cones; for if, on the one hand, the taper be too small, they are
liable to adhere into each other too firmly, and on the other hand, if the taper be too great, they do not
possess sufficient frictional force to keep them in contact.
Another mode of accomplishing the same purpose in small machinery, by means of an epicyclic train,
is represented by Fig. 2097. In this the shaft A A is continuous, and supposed to be that through
which the motive power is transmitted. The wheel a is fast, but those marked b and c run loose on
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GEERING.
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this shaft. The two pinions d d have their bearings in the wheel c c, and geer with the two opposite
bevel-wheels, a and b. (One of these pinions only is requisite to complete the motion; the second being
introduced merely to maintain the equipoise of the system.) If now motion be given to the shaft A A,
it is clear that the wheel b, which is loose, will be made to revolve in the contrary direction to the wheel
a which is fixed, by means of the carriers dd; but no motion of the wheel c, if slightly opposed, will
ensue; and so long as this last remains at rest, the wheels a and b will have the same angular velocity
in opposite directions. But if the motion of the wheel b be opposed by means of a friction gland e,
which can be tightened by means of the T-screw marked f to any degree required, the teeth of that
wheel will serve as fulcra to the carrier pinions dd, which, becoming levers of the second kind, with the
resistance at their axes, they will carry round the wheel c with half the velocity of the prime mover a;
and geering with the wheel h, on the main spindle of the machine to be impelled, will transfer to it the
motion which itself receives. We have supposed the wheel b to be held absolutely still; but it is ob-
vious that it may be brought gradually to rest by means of the friction gland; and as the wheel c can
attain motion only as the motion of the wheel b is reduced, and can attain its full speed only when b is
brought to rest, it is clear that the wheel h, and, consequently, the machine, may be brought into action
without the slightest degree of shock; and, moreover, may be driven at any velocity less than the max-
imum, that may be desired.
2097.
2098.
d
c
a
a
A
A
c
C
Another mode of obviating shock in starting machinery, which has been long in use, is represented by
Fig. 2098. On the shaft B is fixed a drum or pulley which is embraced by a friction-band a as tightly
as may be found necessary; this band is provided with projecting ears, with which the prongs b b of a
fixed cross on the driving-shaft A can be shifted into contact. This cross can be shifted end-long on its
shaft A, but is connected to it by a sunk key, 80 that being thrown into geer with the ears of the friction-
band, the shaft being in motion, the band slips round on its pulley until the friction becomes equal to
the resistance, and the pulley gradually attains the motion of the clutch. The arms and sockets c c,
which are keyed firmly on the shaft A, are used to steady the prongs and to remove the strain from the
shifting part.
This contrivance is susceptible of very extensive application even in large machinery, and may be
variously modified. If the tension of the band be properly adjusted, all shock will be obviated, and
the pulley, and, consequently, its shaft, brought into motion in the same easy way as by a belt.
The principle of this arrangement is frequently and very advantageously applied directly to the
wheels themselves through which the power is conveyed. Such wheels are termed friction-wheels, and
their form and mode of operation will be readily understood. The wheel to which this arrangement is
to be applied is usually the largest one of the train, and is made with an eye as large as can conve-
niently be used. This eye is accurately bored out and made of such a diameter as to fit a centre or
friction-wheel, which is turned truly cylindrical, and is furnished with projecting flanges bearing against
the face of the large wheel In the eye of the wheel, between each arm, small recesses are made, and
into these are fitted pieces of brass. Pinching screws bear upon the back of these pieces, and regulate
the pressure to which it may be deemed necessary to subject the wheel. It is obvious that, should the
resistance at the teeth of the wheel at any time exceed this preseure, the central part, or friction-wheel,
will revolve and leave the wheel itself stationary, thus saving the machinery from fracture. An ex-
ample of the application of this arrangement, which will be familiar to most readers, is seen in dredging
machinery, which, having frequently occasion to encounter such intractable objects as rocks and trunks
of large trees, would be constantly liable to destruction but for this simple and very efficient contrivance.
There is still another mode of accomplishing the same end, which is worthy of notice, on account of
its simplicity. The contrivance to which we refer consists is transferring the motion of one pulley to a
second in contact with it, by means of friction alone. The oldest and best known arrangement on this
principle is to make the contact at the circumferences, which are usually composed of end-wood, SO
that the pulleys may be considered as wheels with indefinitely small teeth. The objection to this
arrangement is the amount of friction produced at the journals by the pressure necessary at the point
of contact of the circumferences to prevent slipping. To obviate this objection it has been attempted,
w.! partid success, to make the pulleys concentric, and to bring the two contiguous sides into
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contact. This modification has been used in hoisting tackle; but while it avoids the friction on the
journals, it brings into action an end-long pressure which must be counteracted, and which, consequently
brings into operation a corresponding frictional force. Still there are many cases in which it might be
employed with advantage.
Bearings.-Another important feature in a system of mill-geering is the mode of supporting the shaft-
ing-the form, arrangement, and general adaptation of the plumber-blocks and steps, and their supporting
apparatus. These are manifold in their proportion and construction-depending, as they do, in a great
measure, on the taste of the engineer and the circumstances in which they are employed. Even the
length of journal in relation to its diameter is far from being a fixed quantity; and as the journals de-
termine the length of the pillows or brasses employed, these last are equally indefinite in their propor-
tions. The range of variation is gradually becoming less as the principle of friction is becoming better
known; but still we find journals made equal in length and diameter; and others having a length
equal to their circumference. These proportions, except for particular cases, are extremes to be
avoided.
Without attempting to establish a general rule for the length to be given to bearings, under all cir-
cumstances, it may be observed, that the pressure upon the pillows or steps ought in no case to exceed
1,000 lbs. on the square inch of rubbing surfaces. Within this limit the wear of the brasses is moder-
ate; but, when a less intense pressure can conveniently be attained by increasing the amount of sur-
face, without a countervailing evil, it ought to be adopted, even to half the pressure stated. To calcu-
late every particular case which occurs in practice, and to adapt the patterns to it, would, however, be
attended with an amount of labor and expense which it is found necessary to avoid; and, accordingly,
the mode commonly adopted is to fix upon two extreme cases, and to proportion the intermediate
lengths to these. Thus, taking a journal of 2 inches diameter, and another 12 inches; and suppose 4
inches to be taken as a proper length for the former and 19 inches for the latter; then the lengths for
intermediate diameters may be assigned by arithmetical progression. Thus, between 2 inches and 12
inches there are 40 quarters, and between 4 inches and 19 inches there are 120 eighths; consequently,
for every increment of & inch of diameter, we have a corresponding increment of I inch of length of
journal.
The common material employed for pillows is a composition of copper and tin, in the proportion of
12 to 1. This alloy is much harder than common brass, and is supposed to work with cast and wrought
iron with less friction, and to be more durable than most other compounds. Cast-iron pillows, espe-
cially when cast in iron moulds, and when the rubbing surfaces are made large in proportion to the
pressure upon them, are not inferior in any respect to the bush-metal commonly employed-the fric-
tion is, indeed, rather less than greater, and being harder, they are still more lasting. But when the
pressure is so great as to produce abrasion of the surfaces when left occasionally without a proper sup-
ply of oil, the wearing process, thus commenced, goes on increasing, and the surfaces never afterwards
acquire the necessary polish. In this the bush-metal has an advantage, for although abrasion has pro-
ceeded a certain way, when the lubrication is again perfect, the pillows take a new polish as perfect
as before, and the abrasion ceases. Wooden pillows are also sometimes employed with advantage.
Box-tree and lignum vitae were long in use, but those woods, besides being much more expensive, are
far inferior for the purpose to home-grown beech. We have known journals which, with ordinary
metal pillows, were ever liable to heat, run for many years on beech-wood without manifesting any
tendency of that kind.
Pure tin is, perhaps, of all other substances, that which produces the least friction with iron; but its
softness has prevented it being very extensively employed. When the pressure upon the rubbing sur-
faces exceeds very moderate limits, the tin yields to it, and becomes extended in the direction of the
length of the pillow. A mode of obviating this difficulty has been patented in the United States by
Mr. Babbitt; it consists in placing the soft metal in a species of casing of cast-iron, of the common form
of the half pillow, but with ledges round its concave surface, which thus presents a recess of a depth
corresponding to the size of the pillow-from 1th inch to an inch in very large diameters. This recess
is filled with the soft metal, which is retained by the ledging of the casing, and prevented from yielding
and becoming extended by the pressure on its surface.
2101.
2099.
2102.
2100.
The material used by Mr. Babbitt is not pure tin, but a soft alloy, in which lead predominates, and
which, besides answering all the purposes of tin, has the advantage of being greatly cheaper.
A patent for a composition-metal has lately been obtained by Mr. Fenton; it is harder than Mr.
Babbitt's metal equally fusible, and still cheaper, and has been found very efficient as bush-metal in
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853
railway engines. It is simply a compound of tin and zinc, with a little copper to harden it and a very
excellent composition of the sort may be made of equal parts of the two former metals and a sixteenth
by weight of antimony to give hardness.
Forms of plumber-blocks and pillows, very commonly adopted for heavy shafts, are shown by Figs.
2099, 2100, 2101, and 2102. In this the pillows are made octagonal to prevent their turning round with
the shaft, and are cast with flanges on their ends to prevent longitudinal displacement. This form has,
however, been departed from by some of our best millwrights. Instead of casting the brasses with
flanges and plane faces, they are cast of a cylindrical form, and with two snugs at the middle of their
length, which, entering corresponding recesses in the plumber-block, retain them securely in their places
when the cover is fixed. By this arrangement they are more easily fitted, contain less useless metal,
and have a lighter appearance. The plumber-block itself, also, admits of being bored out to the size
of the pillows; whereas, with the octagonal form, the faces require to be planed to the required
angles-a much more expensive process.
2104.
2103.
The plumber-block consists of a sole and cover, which, when practicable, are independently bolted
together, the heads of the cover-bolts being countersunk in the sole. The cover is made to check
accurately within the cheeks of the block, the surfaces being planed true to each other, 80 that the
stress upon the bolts is reduced to a minimum. The sole has two projecting ends by which to bolt it
in its place, as shown in Fig. 2103, and elsewhere. The figure specified is an example of a plumber-
block with what is denominated a false or shell cover-a form often adopted for economy when the
pressure is entirely down. In this case there is only one brass, the cover part being cast with side pro-
jections resembling the ends of a brass, and with projections on its upper surface resembling the nuts
and ends of bolts of the regular form represented by Fig. 2099. This cover is not fitted, but is simply
laid loosely in its place, and serves merely to preserve the journal from sand and similar injurious
matters.
2105.
2106.
The form of pedestal represented under the footstep-bridge by Fig. 2107, is one of the best examples,
combining strength, elegance, and simplicity of make. It is in every way appropriate for its purpose.
The base and cover fit together with a degree of symmetry and character which are not found in the
examples above referred to; and the amount of fitting is much reduced. The base and cap being
checked together by planing, they are fixed in their relative position by the cover-bolts, and bored out
to the extreme diameter of the brasses. But instead of a uniform concave surface, the interior of the
base and cap have a circular recess of small depth occupying about a half of their breadth, 80 that the
bored parts occupy about a fourth of the breadth of the concave surface on each side of this recess;
the object of this is to avoid the necessity of turning the exterior of the brasses for an equal extent at
the middle of their length, and, therefore, allows of their being provided with spugs as already noticed,
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GEERING.
'to secure them from turning round in their places with the journal. The brasses being turned to fit
their position in the pedestal, they are bored out concentrical with the outer circle; and the points of
the cap-bolts and the nuts being dressed, the plumber-block is ready to be bolted in its place.
The foundation-plate, upon which the sole of the pedestal rests, is usually provided with snugs, set
so much apart as to allow of a wooden key being driven between them and the ends of the pedestal-
sole. The bolt-holes in the sole and foundation are also made oblong, to allow of a small amount of
adjustment in setting the pedestal; and, to obtain this latitude of adjustment laterally, and also in the
direction of the axis of the brasses, the holes are lengthened in the sole and foundation in the corres-
ponding directions. Adjustment is attained vertically by allowing for a given thickness of wood to be
placed under the sole of the pedestal, and which can be increased or diminished at pleasure to obviate
any small inaccuracy of workmanship.
2107.
In ordinary mill-work pedestals are usually pro-
vided with some form of cast-iron foundation-plate
upon which they are fixed. This is exemplified by
Figs. 2103, 2104, 2106, 2108, and 2107 and it fre-
quently happens that much ingenuity is necessary
to compose what is technically denominated a wall-
box or fixing for the proper reception of the number
of pedestals required by a confluence of shafting to
a point. Fig. 2104 affords an example of one of
the most common and simplest forms of wall-box,
being intended to carry only one pedestal for a shaft
which may be supposed either to pass through the
wall into which the frame is inserted at that point,
or to terminate there. If intended to carry the end
of a shaft. it is usually made in the form of a rect-
angular box with the bottom into the wall, and with
a shelve at a convenient height to receive the sole of
the pedestal, the breadth of which determines the
depth of the box. But when the shaft passes com-
pletely through the wall, the box is simply a rect-
angular frame, corresponding in depth with the
thickness of the wall into which it is inserted and with the cross-shelve, for the purpose before stated.
This makes a neat, convenient, and substantial fixing, and one which is in constant requisition.
Fig. 2108 gives an example of a pedestal wall-plate, and which serves the same purpose as the wall-
box above described, when the shaft terminates at the wall and does not pass through it. This species
of fixing is simply a bracket bolted to the wall by three bolts which pass completely through and are
secured on the outside by wall-washers, bonnets, or stars. These are merely plates of cast-iron, some-
times with radial arms to increase the amount of bearing surface, with holes through their centres, to
receive the ends of the bolts, which being screwed, are retained by nuts passed over them in the usual
manner. Commonly the bolts are entered from the outside, which is generally advisable for conve-
2108.
2110.
2109.
2110f.
nience and safety. The wall-washers serve the purpose of increasing the amount of surface of the wall
acted upon, and thereby allow the bolts to be screwed up more tightly; and the more friable the
material of the wall is, the larger these ought manifestly to be made. For brick walls a very common
proportion between the size of bolt and bonnet, estimated by diameter, is one to six. For dressed
stone walls, the proportion may be somewhat less; but for rubble work the stellar form ought to be
preferred.
The bracket is provided with a projecting sole upon which the pedestal rests, and which is supported
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855
at the middle of its length by a rib cast upon it. The sole has a snug at each end, between which the
pedestal is keyed, and holes through it to receive the pedestal-bolts.
Fig. 2109 represents another form of wall-bracket. This form is employed for carrying a shaft along
a wall, and projects sufficiently to allow space for any wheels and pulleys which may be upon the shaft
to work clear of the wall. The bearing is in this case formed in the bracket itself, and the cover is held
in its place by two bolts secured in the cheeks of the block by cotterals.
As this species of bracket does not allow of any adjustment at the bearing, and as it would be diffi-
cult to adjust, if fitted directly upon the wall, it is usually provided with a wall or ground-plate, as
shown in the figure. This plate is, in the first place, secured to the wall by wall-bolts and washers, in
the manner above described; and the bracket is then adjusted and fixed upon it by bolts and keys, in
the same manner that the simple pedestal is secured to its seat. But sometimes, and judiciously,
its bolts also pass entirely through the wall, and serve to maintain the stability of both foundation and
bracket.
Figs. 2110 to 2112 are forms of pendent brackets intended to carry lines of shafting along the ceiling
of a building. Fig. 2111 is the simplest form, and is often used to carry the weight of the shaft at
points intermediate to those at which the power is taken off, but sometimes also it is the only species of
bracket employed when the shafting is light. It is easily fitted, and has very commonly only an under
pillow for the shaft, and no cover; but when the shaft has an upward pressure-which it must at any
point where motion is transferred to or from it by toothed geer, whose line of contact is in the horizon-
tal plane,-a species of block-brass is fitted into it and retained by a cotter, as shown in the figure. The
ends of this block are checked, and the back of it has a groove to receive the edge of the cotter; it is
thus effectually prevented from moving on end, and may be forced downwards upon the shaft by ad-
vancing the cotter, which is made of a tapering form for that purpose.
2111.
2112.
This form of gallows has, however, no other recommendation than cheapness. It is inelegant in the
last degree, and deficient in stability, is easily twisted out of position in consequence of the oblique
action of the weight upon it ; and, moreover, the hook into which the brasses are fitted being usually
narrow-another feature of economy always associated with it-the brasses soon become loose and
allow a hobbling motion of the shaft, not more unpleasant to witness than it is injurious to all the con-
nections of the line, and to the accurate transfer of the power at the working points.
2114.
2113.
A
B
Fig. 2112 represents a gallows of a more substantial character, but still inelegant in appearance, and,
in some respects, inconvenient. The weight being equally and directly borne by the two supporting
points, it possesses all the advantages of strength; it may be provided with a cover and cover-brass,
which are necessary when the bracket is placed in the vicinity of a pair of wheels which geer together.
The form of bracket has the manifest inconvenience that the shaft cannot be taken out of its place
except by moving it end-long.
Figs. 2110 and 21101 are two views of a form of pendent bracket, which combines to a considerable
extent the two requisites of strength and simplicity. The pillar and expanded base of this bracket are
cast hollow, as indicated by the dotted lines in Fig. 21104. The cover is fitted to the pillar by planed
faces which check together, leaving space to receive a bevel-edged key which holds the cover in its
place when the stress is entirely down wards; but when the bracket is intended to be placed in the
vicinity of two geering-wheels, the cover and projection on which the under pillow rests are provided
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GEERING.
with snugs through which a nib-bolt, as it is technically called, passes and assists the key in retaining
the cover in its place.
This form of pendent is also convenient to the millwright as a pattern. In the two forms above
described, any difference of length is attended with extensive alteration of the pattern, but in this, the
stalk of the pattern is made at least as long as there is any probability of its ever being required a
series of ferules are then turned to fit upon the stalk, and of the requisite outside diameter; the
necessary number of these are put on to make up the length less the length of the octagonal part which
forms the bearing; this part is formed of cast-iron, and has also a hole through it to receive the stalk,
and when put on and fixed in the proper position the bracket is ready to be moulded, any part of the
stalk which may be projecting through being cut of in the sand. The process of moulding is likewise
simple, and no core-box is required, except when the bracket has a double bearing, which is always the
case when it is intended for a point at which a bevel pair meet.
The only objection to this form of bracket is the oblique direction in which the strain falls upon the
holding bolts, and which might be obviated by making the cover one piece with the stem, and checking
the under bearing to it by a strong dovetail and single holding-bolt, the office of which would simply be
to prevent end-long motion.
Pendent brackets such as those here described, are sometimes cast with vertical soles, prepared to
bolt to beams; but more frequently the soles are horizontal; and in that case are bolted to grounds of
planking fixed between two adjoining beams by wood-screws. When the brackets can be attached to
beams, that mode of fixing is, however, to be preferred and in that case the sole ought to be formed
with a projecting rib to bear against the under side of the beam, and relieve the bolts as much as
possible of strain.
The kinds of bearings described are all designed to support shafts placed horizontally; but in almost
every system of geering there is one large vertical shaft from which the minor horizontal shafts derive
their motion. The bottom extremity of the vertical shaft is supported on a species of bearing techni-
cally named a foot-step, of which Fig. 2107 represents a specimen. In this case, the motion is usually
transferred by a pair of bevel-wheels, as represented by Fig. 2001, and more completely still by the
arrangement shown in Fig. 2115. In this last the first shaft is marked H; on this is the spur pinion Q
2115.
F
D
E
4
B
C
G
L
K
H
WHITHEY.SC.
which geers with the equally pitched wheel F on the horizontal shaft K. On the other extremity of
this shaft is the bevel-wheel C, which geers with a similar wheel on the vertical shaft and through
this last wheel motion is communicated to the equal wheel B and the geering on the right. The
arrangement represented by Fig. 2001 is strictly analogous-the horizontal shaft being the driver and
the vertical shaft the carrier of the motion to the superior parts of the factory.
In these arrangements the foot-step of the vertical shaft is carried upon an arch, technically a foot-
bridge, of which Fig. 2107 gives a front view, and Fig. 2115 a side view: Fig. 2001 shows a section of
the same through the foot-step box. This bridge rests on a foundation-plate of cast-iron, which in turn
is fixed upon a stone foundation more or less substantial, according to the weight and stress which are
to be resisted. The pedestal of the horizontal shaft ought to be supported on the same foundation
sole: for, if supported on a separate sole, the foundation bolts, and possibly the foundation itself, will
in all probability be soon destroyed by the twisting action of the wheels at the fixed points. The foot-
step box occupies the summit of the arch; three sides of it are cast upon the bridge, but the fourth side,
which forms the door, is a separate casting, attached by four bolts which pass right through from back
to front of the box, hollow rolls being cast on the two opposite sides for that purpose. In Fig. 2107
the door is supposed to be removed to show the interior arrangement; Fig. 2001 gives a transverse
section through the door, showing its thickness; and Fig. 2115 shows the door in its place and fixed by
its bolts. This door is fitted with great exactness, and the whole interior of the box-at least a
sufficient bearing surface of it at the angles-is chipped and filed true: a foot-plate as in Fig. 2001,
and sometimes a species of box solid above, and sometimes both, is fitted into the bottom of the box.
This plate or pillow is first planed and in fitting, its superior surface is set truly square with the sides
of the box. The surface of the plate is frequently steeled by case-hardening when the end of the shaft
is intended to be rested immediately upon it, as shown in the drawings referred to; but more commonly
it is simply a plato of cast-iron on which the bottom of the cup-formed brass is supported. In these
drawings the brass is supposed to be without bottom, and to embrace the cylindrical end of the shaft,
and support it laterally. This arrangement has its advantages, in so far as the foot-plate can easily be
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replaced when worn out; and the brass may be formed in halves, which will allow it also to be replaced
with little difficulty. But more commonly the brass has the form of a deep cup, interiorly while,
exteriorly, it is made in size exactly to fit the box. On one side-that from which the wheel acts-a
recess is left in the interior to receive and retain oil in considerable quantity, so that the lubrication may
be abundant and prevent heating. With every attention to lubrication it is, however, very difficult,
when the weight upon the step is great, to prevent its becoming hot, evaporating the oil, and destroying
the rubbing surfaces. Various modes of remedying the evil have been attempted; but the best expe-
dient hitherto tried is to enlarge the surface as much as convenient. Formerly, the end of the shaft was
greatly reduced to form the foot-often, indeed, a pin was inserted and made to serve the functions of a
foot; but at present the foot is formed on the same principle as any other bearing-namely, with as
much bearing surface as the diameter will allow. But even this is often found too little, and the next
resource is to continue the wheel boss and give the foot a conical form, thereby increasing the supporting
surface as much as circumstances will admit.
We have also seen attempts to line the brass step with ribs of steel to increase its durability; but
without success. A step made on Babbitt's principle, and lined with soft metal, would, in our opinion,
offer a better chance of success than any scheme which has hitherto been attempted. But the experi-
ment remains to be made on a proper scale, and with sufficiently good workmanship, to test the principle
thoroughly before its being adopted very extensively in mill-work.
Among the more ingenious of the older contrivances for rendering foot-bearings durable was that of
attaching a hardened steel plate to the extremity of the foot by a square tang, which was driven hard
into a corresponding hole in the foot. On the under side of this disk a groove was cut across, the better
to distribute the oil which found its way to the bottom of the step by vertical grooves cut in it.
This was found to work very well when there was little lateral stress upon the shaft; but ultimately
gave place to an arrangement which is sometimes adopted in modern work, and which consists in
inserting a steel pivot into the lower end of the shaft. When this pivot is bound in its place by a
malleable-iron ring put on hot, the arrangement is one of the best which can be adopted; but the
original mode of simply boring a hole in the end of the shaft and inserting the pivot, without any
further lateral support, left the foot very weak and inadequate to sustain any considerable amount of
lateral stress.
Another scheme, also sometimes put in practice in modern work, when the shaft is very large, is to
make the foot turn on conical rollers, on the same principle as horizontal shafts are sometimes made to
turn on parallel friction rollers to diminish the amount of friction, by converting a rubbing into a rolling
motion, with only the sliding action of the small axes which retain the rollers in their places. The
cones, however, require very accurate workmanship, and therefore become expensive. and are, moreover,
very liable to get out of order; they are, in consequence, very seldom employed. A modification of the
conical rollers, consisting of a single ball placed under the foot of the shaft, although very rarely tried
in mill-work, seems to offer advantages more than equivalent to the additional workmanship which it
would entail, by dividing the motion, in some measure, between the shaft and itself, and leaving an
open space to receive oil, which would tend materially to keep the foot cool. This arrangement is
almost universally adopted in vertical sugar-mills, and is found to answer, although in process of time
the ball does become flattened, and, accordingly, requires to be replaced.
The scheme of the late Mr. Bramah, of supporting the pivot entirely on water, the pressure of which
was to be maintained by a small forcing-pump and stop-cock, would, if all tear and wear could be
avoided, be perfect; but unfortunately it holds out little prospect of being successfully applied to the
end in question, although there appears little doubt that it will ultimately be found both practicable
and efficient as applied to railway turn-tables, in which the bearing surface is large, and the only prob-
lem to be resolved is the diminution of friction.
Water has been successfully applied to keep the common foot-step cool, by simply perforating the foot-
box and running a stream constantly through it. An example of this may be seen at the Deanston mills.
Sizes and proportions of bolts.-The bolts employed in securing together the pedestals and parts of
the fixings of shaft-geering constitute another important element in mill-work. Bolts may be generally
described as pins having a head formed on one end, and the other end screwed externally to enter an
internally screwed ring, technically named a nut. When the bolt is passed through holes placed oppo-
sitely in two pieces, a thin ring or washer being first placed on the screwed end of the bolt, if the nut
be then put on and screwed tightly down upon the washer the two pieces will be held firmly together
between this last and the head, the body of the bolt, or part between, serving as the medium through
which the force is maintained by one surface upon that opposite.
Bolts are denominated according to their diameters of the body part, +inch, §-inch, 4-inch, I-inch,
1-inch, 14-inch, &c., bolts; the particular diameter being determined in any case by the supposed tension
to which the bolt will be exposed. It is rarely that this force can be estimated even approximately;
but assuming it to be known, the tension ought not to exceed 11 ton on the square inch of section.
Therefore, if we designate by T the tension in tons, that is, the effort tending to separate the head and
nut by tearing the body part of the bolt asunder, and the diameter in inches by D, we have the simple
formula,
D=&VT.
Thus, supposing the known tension to be nine tons, then,
D=1/9=2} inches,
the diameter of the bolt necessary to resist that pressure.
The number of consecutive threads in an inch, that is, the pitch of the screw, is regulated by the di-
ameter of the bolt. For small bolts of about +inch the pitch is usually about a sixth of the diameter, but
relatively decreases inversely with the increase of diameter.
The following table is that of the dies and taps of an extensive millwright and engineering establish
ment in Glasgow, and it does not differ sensibly from the numbers adopted in some other works.
108
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The depth of the thread is also a matter of importance. The section of thread most approved of for
strength and easy motion of the nut is an equilateral triangle, thus 4, the bevelled sides being equal be-
tween themselves and to the base or pitch.
Bolts of larger diameter than those
Diameter of
Threads in an
Diameter of
Threads in an
named in the annexed table are usually
screw in inches.
inch.
screw in inches.
inch.
chased in the screw-cutting lathe, and in
that case the thread is commonly made
12
11
5
of a rectangular section; but such bolts
to
11
11
41
are very rarely required in mill-work,
t
10
2
41
and when they do happen to be employ-
#
84
21
4
ed, it is under such circumstances as re-
1
8
21
4
move them from the ordinary class of bolts
1g
71
21
st
and the proportions therein recognized.
11
7
21
st
The length of the body of the bolt
1]
6}
21
8
must, of course, depend upon circum-
11
6
3
3
stances; but a certain proportion is ob-
11
51
served between the diameter and the
sizes of head and nut. For common bolts the head is usually square, and the nut six-paned, that is,
has six facets on its periphery. Sometimes, also, the head has the same form, and occasionally it is
made round, and for particular purposes it is conical, but oftener pyramidal. When of this shape, it is
intended to be flush or even with the surface of the piece into which the bolt is inserted, and it is then
said to be countersunk. The cover-bolts of pedestals are of this form, being necessarily flush with the
sole of the pedestal. The thickness of the head when of the usual form is from two-thirds to three-
fourths of the diameter of the bolt; and the diameter of its circumscribed circle is double of the primary
diameter. The thickness of the nut is usually made sufficient to contain from eight to ten threads, the
smaller having proportionally the greater depth. The part of the body towards the head, equal in
length to a third of the whole, is usually made square, and the remaining part or two-thirds is round
and of this a portion equal at least to double the thickness of the nut is screwed. Sometimes, however,
as in pedestal cover-bolts, the whole length of the body is cylindrical, the bolt being prevented from
turning round when the nut is being screwed up by the pyramidal countersunk head.
Although the length of bolts generally can only be assigned for particular cases, those adapted for
particular sizes of pedestals may be given. These, it is true, will vary with the particular form of pe-
destal used; but the sizes given in the following table will be found very generally applicable for those
of good proportions.
Diameter of
Diameter of
bolts.
Holding.
Cover.
Double-ended.
journal.
Inches.
Inches.
Inches.
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Inches.
11
31
41
21
5
11
CORP
31
41
21
5
2
onto
34
5
21
6
21
4
4
57
21
61
21
4
51
21
61
24
41
61
8
71
8
8
41
64
3
74
31
8
4b
71
3g
81
31
at-s
41
8
34
84
34
1
41
81
31
9
4
1
5
9
34
91
41
11
51
91
4
101
41
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101
41
11
61
101
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111
5
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51
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6g
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54
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51
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7
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51
134
61
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7t
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6
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7
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81
15
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71
2
87
151
61
17
71
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61
171
71
21
91
161
7
18
8
21
91
171
71
184
81
21
91
181
74
191
81
21
10
191
8
201
9
2g
101
20
84
21
91
21
11
201
81
22
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GIG.
859
The heads of bolts intended for wood are commonly segments of a sphere; and the bolt is not often
provided with a nut, the holding being in the wood itself. But sometimes, when the wood is thin, the
screw is passed sufficiently far through to take a broad wash and nut above it, an arrangement which
gives strength in proportion to the acting surface.
Guide pulleys.-It frequently happens, when the power is to be conveyed by a belt, that the connec
tion cannot be obtained directly, in consequence of the relative positions of the shafts, which may be
placed obliquely to one another; and sometimes other parts of the geering, machinery, cross-beams of
the building, and the like, come between the points to be connected, and by their intervention prevent
the belt from passing immediately from one point to the other. Under these circumstances, it is ne-
cessary to pass the belt over guide pulleys.
An example of the common guide-pulley frame is given in Figs. 2113 and 2114. The axes of the
pulleys are adjustable in the frame B to any required angle within a certain range in a common plane,
which is parallel with a plane passing through the driving axis and perpendicular to the plane of the
driven shaft. When the belt, therefore, passes from the driver over one of the guide pulleys and is
returned upon the other, the bight will be thrown into a plane at right angles to the normal plane, and
a pulley placed in that plane, its axis coinciding with it, will be driven by the belt without any ten-
dency to change its plane of action.
We have supposed the beams to be parallel and perpendicular to one another; but the arrangement
may be adapted to other positions by placing the guide pulleys in different planes; and in order to
allow of further accommodation, the frame may be made adjustable at the point of attachment to the
beam at D.
The above treatise on geering has been taken from the Engineer and Machinist's Assistant, and is
generally admitted to be the best yet published.
GEODESY, literally signifies the division of the earth, in which sense it is synonymous with land
surveying; but it is usually employed in a more general sense to denote that part of practical geometry
which has for its object the determination of the magnitude and figure either of the whole earth, or of
any given portion of its surface. In this sense it comprehends all the geometrical or trigonometrical
operations that are necessary for constructing a map of a country, measuring the lengths of degrees, &c.
In order to construct an accurate map, or determine the form and dimensions of a country, it is necessary,
in the first place, to determine the absolute distances between the several stations or points secondly,
to determine the azimuths of the lines thus measured, that is, their situation with respect to the meridian;
and thirdly, the differences of latitude and longitude of the stations. The operations necessary for de-
termining the absolute distances, comprehending the measurement of a base, the observation of angles,
the computation of the sides of the triangles, and their reduction to the same level, are called the
geodesical or geodetical operations; while those which are required for determining the azimuths and
latitudes are called the astronomical operations. The determination of the figure and dimensions of
the earth is a problem of very great importance to astronomy and geography, and has accordingly at
all times been a subject of much interest to mathematicians; but it is only since towards the middle
of the last century that operations on an adequate scale for its solution have been undertaken in differ-
ent parts of the world.
GERMAN SILVER. An alloy composed of copper, nickel, and zinc, in various proportions, accord-
ing to the purposes for which it is to be used. As a substitute for silver, it should be composed of 25
parts of nickel, 25 of zinc, and 50 of copper. An alloy better adapted for rolling, has a larger propor-
tion of copper, 60 parts, and less of zinc, 20. For castings, as candlesticks, bells, &c., 20 of nickel, 20 of
zinc, 60 of copper, and 8 of lead. The analysis of the true German silver from the mines of Hildburg-
hausen, gives of copper 40·4 parts, nickel 316, zinc 25.4, iron 2-6.
GIG, for napping cloth. Fig. 2116 geer end of gig. Fig. 2117 is a front elevation of gig.
The cloth to be napped is first wound on the roller c', passed down over the two straining rollers d' d',
2116.
, the cloth roller c. By means of the shaft c, which is mounted at each end with two slipping
clutches ff, c' is thrown out of geer, and the lower roller c thrown in. The cloth is then drawn down-
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GILDING.
2117.
wards over the revolving drum b, which is set with teazles, as seen in Fig. 2118, until the whole length
has passed over.
2118.
The action of the two cloth rollers is then reversed, c' being thrown into geer, and the cloth passes
back again over the teazles, and this is continued until the nap is sufficiently raised. The straining
roller d' may be adjusted to give more or less strain on the cloth at will.
GILDING is the covering, with a plate or film of gold, metallic or other surfaces. The application
is either for utility, as where it prevents the oxidation of drinking or other vessels for domestic use,
of watch-springs, and the steeled parts of small machinery; or for ornament, as in picture and japan
frames. Its use under the former of these aspects is daily extending.
Gilding is effected by several different processes.
1. By means of an amalgam of gold and mercury, which is best made by heating pure mercury in
a black-lead crucible to near the boiling point, and adding one-sixth or one-seventh in weight of fine
gold in very thin plates, first brought to a red-heat. The mixture is then stirred, until the gold is dis-
solved and well incorporated with the quicksilver. When cooled, the resulting mass is subjected to
gentle pressure in soft porous leather, which separates the excess of mercury; and there remains in the
skin a yellowish silvery-looking substance, which is the amalgam.
In gilding silver, this amalgam is rubbed over the surface, which is first well cleaned, and the mer-
cury is then driven off, by exposing the article operated on to a clear charcoal fire. It is then to be
burnished.
The surface of copper and brass, after being cleaned, may be rubbed over with a solution of proto-
nitrate of mercury, which is decomposed, and leaves a thin pellicle of metallic mercury to amalgamate
upon the surface. This insures the union of the gold amalgam, which is then rubbed on, heated and
burnished, as before. In this mode surfaces may be completely coated with an exceedingly small
proportion of gold, as is shown in the case of brass buttons, of which 144 may be covered on both sides
with the consumption of not more than five grains of gold.
In gilding iron and steel with amalgam, a solution of mercury in nitrous acid is previously applied.
A deposit takes place of mercury in close contact with the surface, even if it does not appreciably
amalgamate with the iron. It facilitates the adhesion of the gold amalgam, which is applied and
treated as before. This method for iron and steel cannot be recommended; for the nitrous acid
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GILDING.
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liberated attacks the surface, and impairs its polish; and the heat, besides, necessary for driving off the
mercury, injures the temper of the metal. Cutting instruments, therefore, or any that require to be
tempered, should not be gilded in this manner. The application of gold leaf to such instruments for
the same end is similarly objectionable for the same reasons.
Another process for iron and steel consists in applying a solution of sulphate of copper previous to
rubbing on the gold amalgam or laying on the gold leaf. This is as exceptionable, and for similar
reasons, as the former method.
2. Better than either of the last-mentioned, at least for iron and steel, is the process with etherealized
gold. In this a solution of gold is made in nitro-muriatic acid, and there is added to it twice as much sul-
phuric ether. The mixture must be shaken, and then allowed to repose, when the ether with the chloride
of gold will separate from the remaining liquid, and rest above it. This dark-colored ethereal solution is
poured off from the light-colored liquid beneath, and can be preserved for use in tight bottles, excluded
from light. When applied, it is with a very fine brush, or camel's hair pencil; the ether evaporates
immediately, leaving a coating of gold. This is burnished after being heated. The adhesion is more
perfect, however, if the article be raised to a temperature approaching redness.
3. A mode of gilding silver is sometimes practised, which consists in reducing to ashes linen rags
that have been previously dipped in a solution of chloride of gold, and rubbing them on the surface to
be gilt with a piece of leather, cork, or with the finger. The fine particles of gold will thus adhere to
the silver. The article is then washed to receive the adhering ashes, and burnished. This is a simple
and easy method, and consumes but little gold.
Brass or copper may be readily gilt, by being dipped in a dilute neutral solution of chloride of gold,
and then washed and burnished.
For the preparation of the chloride of gold, see GOLD.
4. A process analogous to this last was patented in 1836 by Elkington, an English gilt toy-maker,
and is well adapted for small articles. It consists in immersing them in a hot solution of chloride of
gold, to which has been added a considerable excess of bicarbonate of potash.
5. By far the neatest and most unobjectionable among the chemical methods of gilding is the galvanic
process, proposed first in 1840 by De la Rive. Since then it has received, in the hands of various per-
sons, modifications facilitating and extending its application. For these and other details, see ELECTRO-
METALLURGY.
Gilding is also effected:
6. Mechanically, by covering with gold-leaf, which comprehends a very extensive range of applica-
tion. Thus, the principal metals may be gilt; thus, several natural or artificial earths, such as marble,
plates, and porcelain, objects in glass, leather, paper or pasteboard, and wood, may be made to assume
entirely, or in part, the appearance and some of the physical advantages of gold.
For work intended to be out of doors, or exposed to the weather, a sizing is first applied, made of
boiled linseed-oil and red ochre. On this the gold-leaf is laid. This is the oil-gilding of the older
treatises. In gilding glass or porcelain, powdered gold is mixed to a proper consistence with a solu-
tion of borax in water, and applied with a soft brush or pencil. The articles are then heated in an
oven to a temperature sufficient to burn off the gum and vitrify the borax, whereby the gold is
cemented to the surface. Then it must be well burnished. The general method of using gold in pow-
der (for the various preparation of which, see GOLD) was known and described in the earlier treatises as
gold japanning. But in the true japanning, the gold was protected by a varnish, and not burnished.
Leather is gilt by dusting the surface with powdered mastic, upon which the gold-leaf is applied and
burnished. The lettering and other emblems on bound books is generally done without sizing, by
applying the gold-leaf to the leather, and imprinting with the stamps or types moderately warm. In
lettering on muslin, mastic or isinglass is better to be applied.
Paper, or parchment, is gilt by applying a thin coat of gum, or size, laying on the gold-leaf before
the coat is perfectly dry, and burnishing, as before. The edges of books are best gilt by applying to
them in the press a thin size of one part powdered rock-candy and four parts Armenian bole, mixed
with the white of egg then the gold-leaf is put on and burnished.
Articles in wood, such as picture and mirror frames, are best treated with a sizing prepared from
clippings of vellum or parchment, boiled in water to a stiff jelly, and mixed with Paris white, plaster
of Paris, or yellow ochre.
For gold inks, permanent and sympathetic, see INK.
False gilding, is the application, for cheapness, of other substances than pure gold, in which, how-
ever, the appearance of that metal is more or less imitated. For this purpose is used Dutch leaf,
(which is copper gilt, and then beaten out,) and silver, and tinfoil. The Dutch leaf has the appearance,
at first, of true gold, which may be secured and continued by a coat of transparent varnish. Silver and
tinfoil assume the appearance of gold by means of a varnish or lacker composed of aloes, gum-sandarac,
and white resin, (the resin being about as much as the other two ingredients, whose propositions are
nearly equal,) which are boiled in their own weight of linseed-oil. When well boiled to a syrup, about
a half per cent. of red-lead is added, and the liquor strained through a flannel bag. This was the
method formerly used for the leather hangings of apartments, beautiful specimens of which are still
seen in Europe. These hangings have long gone out of vogue, but will probably be recalled.
For what concerns the details of the art of gilding, the precautions to be taken in the several pro-
cesses, the apparatus and implements employed by the practical workman, and the method of pro-
ducing different characteristics in the work-frosting, deading, &c., &c-reference must be had to larger
treatises and manuals ; among which may be mentioned chiefly, D'Arcet Mémoire sur l'A: de Dorer.
Paris. 1818.
That the ancients practised this art, though in a more expensive manner than W', do, is apparent
from the Egyptian and Etruscan remains, which date back three thousand years, and more. Pliny the
Elder has left fine details of its state in the first century of our era. As well 's can be made out in
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862
GIN.
the uncertainty of weights and measures, the thinnest gold-leaf then was about twenty-two times thicker
than what can be made now. The methods were the same in principle as our own. Marble, and
articles that would not bear heat, were coated with white of egg; wood, with divers kind of glue; al!
generally termed leucophoron. Metals were gilded with native or prepared quicksilver (hydrargyrum),
and the various washes of salt, vinegar, and alum are also mentioned. (Plin. Hist. Nat. xxxiii. 20.)
The relics of Herculaneum, for instance, show that the success of these ancient processes, whether due
to labor or otherwise, is far more than proportionate to what might be expected from our superiority
in theoretical science.
GIMBALS, or GIMBOLS. A piece of mechanism consisting of two brass hoops or rings which
move within one another, each perpendicularly to its plane, about two axes placed at right angles to
each other. A body suspended in this manner, having a free motion in two directions at right angles,
will assume the vertical position: hence the apparatus is employed for suspending portable or mountain
barometers, sea-compasses, &c.
GIN. This term is applied in mechanics to various and widely differing machines, to engines for
raising great weights, driving piles, &c., as well as those employed in cleansing of cotton and wool, and
its preparation for the market or for carding. The most simple, as well as the most ancient, cotton-
gin is the roller gin, which consists of fluted rollers about five-eighths of an inch in diameter, and from
nine to sixteen inches long, placed parallelly in a frame, which keeps them almost in contact. The
rollers revolve in opposite directions the cotton is drawn through between the rollers, whilst the seeds
are prevented from passing from the narrowness of the space. This machine is still used for the finer
and longer stapled cottons but the operation is tedious and expensive; and the saw-gin, invented by
Eli Whitney, in 1793, from its general use, and its wondrous effects on the extension of cotton cultiva-
tion, and influence on manufactures and commerce, may now claim distinction and consideration almost
exclusively as the cotton-gin. In its main features this machine still continues as first invented by
Whitney; but in various details and workmanship, it has been the subject of many improvementa.
Fig. 2120 represents a perspective view of a cotton-gin, constructed by Bates, Hyde & Co., of the Eagle
2120.
o
a
@
0
D
Cotton-Gin Manufactory, Bridgewater, Mass., who are the owners of several patented improvements on
the machine, and from whom we take the following drawings and descriptions. Fig. 2121 is a section
of the gin.
The frame of the machine is made either of wood or iron, usually of wood, with tenons and mortises,
and screwed together firmly with joint-bolts. The sides are ceiled with boards inside the timber, and
the top ceiling above the brush is made in one piece, 80 as to be readily removed.
The grate-fall, or breast, into which the seed cotton is thrown, is formed with ends, or heads, of cast-
iron, and pear-shaped; the lower and back side being composed of cast-iron grates, screwed firmly to
the wood-work of the breast; the saws projecting through the interstices between the grates, from one
to two inches; the upper and back part of the grate-fall, called the "hollow," is hung upon hinges, and
may be raised or lowered at pleasure, and fastened in any desired position by joint-bolts through the
grate-fall heads.
The seed-board makes the front part of the breast, and stands nearly perpendicular, leaving a space
between it and the grates for the discharge of the seed; it is hung upon pivots at the top at each end,
80 that the bottom may be swung outward and the hopper emptied at any time. When in place, the
bottom is fastened by small slide-bolts. The position and angle of the seed-board may be readily varied
and adjusted, bv altering the position of the slides upon which the pivots rest. These slides are fixed
to the grate-fall heads by small bolts passing through slots, having a nut outside.
The grate-fall, or breast, is hung to the front top timber of the frame, by stout hinges above the
saw-cylinder. and the lower part rests upon two short screws in the front piece. That part of the hinge,
or butt, which is attached to the top timber is 80 fixed as to slide up or down by means of slots and an
adjusting screw, and is fastened in the desired position by bolt-nuts.
The saw-cylinder is made of wooden staves, about two inches thick, upon an iron shaft, and turned
in a lathe of a uniform diameter; and, by the application of a small saw, when in the lathe, grooves
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GLASS.
863
are formed to receive the saw-segments, which are made of the best cast-steel, and inserted and fastened
into these grooves.
There is a set of wooden grates behind the saw-cylinder, and a row of hair, or bristles, called the
"moter," to separate the false seeds, motes, and dirt from the ginned cotton.
The brush is made of about twenty inches diameter, cylindrical, having slits lengthwise between
2121.
a, Grate-fall head, or end of breast.
I
b, Seed-board.
a Saw-cylinder.
d, Saw.
a " Patent detached grate."
f, Screw or bolt on which the grate-fall rests.
8. Back board, to which are attached the back
grates and 66 patent moter."
m Grate-fall hollow, which is hung upon hinges,
and THy be raised or lowered at pleasure.
i, Sliding-butt, by means of which the saw-tooth
may be made to assume any desired angle with
the curved surface or front of the grate.
j, " Patent brush."
k, Sliding mote-board.
4 Bottom board.
K
the rows of bristles, and a hole around the shaft to receive the air as the brush revolves; and a rapid cen-
trifugal motion is given to the air, which is forced out with great power between the rows of bristles.
Behind the brush is an opening, the length of the frame, into the lint-room, and beneath the brush a
sliding-board, called the mote-board, which may be slid back or forward for the purpose of regulating
the draft of the gin, and properly separating the motes, dirt, and leaf from the clean cotton.
In the saw-gin, as ordinarily constructed, the cotton is liable to collect in the spaces or interstices
between the grates, and around them above the saws, thus choking or clogging the grate, and pre-
venting the rising and free escape of the roll of seed-cotton. The patent detached grate, instead of
being attached directly to the wood part of the breast at the top, has an arm or brace extending out
behind, through which it is screwed to the wood, so that the top of the grate stands out and is detached
from the wood, and has a space behind of a quarter inch, or more, between it and the wood, and also
a space between it and the adjacent grates; so that there is no chance for the cotton to collect above
the saws, and the choking is entirely avoided.
Many efforts have been made so to improve the saw-gin, as to separate from the fibres of cotton
motes and other impurities. By some this has been essayed by means of rotating brushes acting on the
fibres, and carrying them from the grate to the stripping-brush, rotating in a reverse direction to the
saws. Some have used stationary brushes, through which the saws carry the fibres to be stripped of
motes and other impurities. The objection to these is, that they act on the cotton only when upon the teeth
of the saws, and therefore, instead of separating the motes and other impurities from the fibres to which
they adhere, sometimes with considerable tenacity, the fibres are drawn out with the motes, thus occasion-
ing considerable loss of cotton. The object of the moter is to avoid this loss, and to hold on to the motes
or other impurities, as the fibres are stripped from the saws by the stripping-brush, the fibres being
under the operation of both brushes at the same time. The moter also more effectually stops the
current of air generated by the rotation of the stripping-brush from acting on the fibres before they
are cleaned, than if located at a greater distance from the point of action of the stripping brush.
GLASS.-The varieties of glass are usually classified according to their technical uses, as follows:
A. Bottle-glass, which comprises all glass worked into the form of vessels, &c. It is subdivided, accord-
ing to the purity of the metal of which it is composed, into
Ordinary bottle-glass, consisting of silica 60, potash or soda 3·1, lime 22.3, alumina 8, and oxide of
iron 4.
Glass used for medicinal bottles, composed of silica 716, soda 10-6, lime 10, alumina 3, and a very
little protoxide of iron.
White bottle-glass, for bottles, tumblers, tubes; containing silica 717, soda or potash 15, and lime 10.
B. Windown-glass, composed of silica 70, potash or soda 15.2, lime 13·3, and alumina 1.82.
C. Plate-glass, composed of silica 72, soda or potash 17, lime 6.4, and alumina 2-6. This variety
only differs from the preceding by the greater purity and freedom from color of the materials.
D. Flint-glass, used for grinding, &c., composed of silica, potash, and oxide of lead.
E. Crystal, for optical purposes, composed of silica 592. or boracic acid, potash 9, and lead 28.
F. Strass. The mass composing the imitations of precious stones, consisting of silica 44, potash 12,
with the largest amount of oxide of lead 43, and colored by various metallic oxides. The pigments
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864
GLASS.
used by artists in glass and porcelain, are also included under this head; they are easily fusible glass
fluxes, consisting of lead and boracic acid, which can be colored in any manner that is required.
G. Enamel, composed of silica, soda, and oxide of lead, but rendered opaque by oxide of tin or anti-
mony. These proportions are not adhered to strictly, but vary greatly in different specimens.
Some of these varieties of glass are in themselves colored, as the dark-brown or green bottle-glass
the light-green bottle-glass, used by chemists; all the varieties mentioned can, however, be colored
artificially.
Of the material for glass-making.-In so extensive a branch of manufacture as that of glass, it is
quite impossible to prepare or obtain the ingredients in a state of chemical purity previous to fusing
them together; certain crude products of art and nature are therefore used, in which the ingredients
are contained in some suitable form of combination, and it is left to the process of melting to eject the
impurities in a more or less complete manner. In order to understand the nature of this process, and
the recipes for mixing the ingredients of the different varieties of glass, it is necessary previously to
become acquainted with the crude products which are used in the glass-house for affording silica and
the bases.
Silicic acid-Silica is very abundant in nature, but is seldom sufficiently pure for the manufacture
of the finest colorless glass. Rock crystal is frequently used for those glasses which are employed as
pigments by glass painters. Heated to redness and thrown into water, the state of aggregation of this
substance is 80 changed, that it can easily be reduced to powder. Massive quartz and flint are treated
in the same manner. Sand, however, is the most general and economical source of silica, and renders
the process of grinding unnecessary. The great variations in the purity of this material, render a care-
ful selection necessary for the different kinds of glass.
Potash and soda.-The alkali used in the manufacture of ordinary colored glass, (e. g. bottle-glass,)
is obtained, as far as the potash is concerned, from common ashes, and the soda from the ashes of sea-
plants, or refuse soda. Better kinds of glass are made with crude potashes and soda-ash, and the best
from purified potashes and soda-ash.
Lime.-Every kind of limestone is applicable to the manufacture of glass that is not too poor after
being burnt and slaked. When a glass mixture contains more lime than the silica which it comprises
is capable of saturating, the excess attacks the material of the crucible, and extracts silica from it; the
crucibles are thus quickly eaten away and rendered useless. It is consequently not advisable to em-
ploy more than 20 parts of lime for 100 parts of sand.
Lead-Lead-glass is fused from a mixture containing litharge or minium, (red-lead.) The latter
substance is preferred, on account of its finer state of division.
Discolorizing matters.-White glass seldom or never turns out quite colorless by itself, even when
proper proportions and the purest materials for the mixture have been employed in its production.
There are always two antagonistic elements to contend with, carbon, or carbonaceous matters, and iron,
which have to be overcome by the so-called discolorizing material. Peroxide of manganese, arsenic,
and saltpetre, belong to this class of substances. In all cases the color is removed by oxidation.
Broken glass, or cullet.-Fragments of old glass require particular notice as an indispensable addi-
tion to the ingredient of the crucible. The waste glass in the glass-house, and that collected in the
neighborhood, is carefully sorted, cleaned, ground, and incorporated with the mixture for similar kinds of
glass. These fragments exert a very beneficial action-in addition to the advantage derived from their
being reconverted into glass vessels-by inciting fusion and by aiding the union of the bases with the
silicic acid.
Of the fuel.-The furnaces employed in glass-houses are intended not only to combine chemically
the ingredients of the glass mixture at a glowing heat, but also serve to retain the glass after fusion in
a proper state of fluidity for working.
Again, the reheating of the different vessels during working, which is always effected in the glass-
furnace, requires imperatively a flame fire. That kind of fuel will naturally have the preference which
produces the most intensely hot flame, and causes the least amount of damage to the glass and to the
sides of the furnace from the deposition of ash. In Germany, wood is generally employed, and in some
few places peat; in England and France, coal; in this country, both wood and coal. The best air-dried
wood would fall far short of producing the desired effect, in consequence of the water which it contains,
(from 15 to 20 per cent.) In has been the practice to bake the air-dried wood in a furnace until the
whole of its water has been volatilized. Even this precaution is not perfectly effectual unless soft
woods are selected containing a large proportion of hydrogen; and these are cleft into very small
billets. Finely cleft wood burns more rapidly and without smoke by coming into more extensive con-
tact with air, it evolves its heat in less time, and although a greater amount of heat is not produced by
its means, that heat which is produced, is more intense.
The furnaces.-The construction of the melting furnaces in a glass-house is attended with many diffi-
culties, against which it is almost impossible to provide; and the wear and tear becomes a serious
item to the manufacturer.
The furnace is erected over a large flue, or cave as it is technically termed, very strongly constructed,
and 5 or 6 feet high. On each side of the grate-room, in which the flue terminates, a bank is raised,
termed the siege, on which the pots are placed, 80 that the fire lies, as it were, below the bottom of the
pots, and in the centre of the furnace, but stretching through its whole length. The sides of the fur-
nace are a little higher than the top of the pot, and the arch, or crown, is made as low as possible, to
be consistent with durability. Openings are made in the sides of the furnace, opposite to each pot, and
above all, a high cone is erected for the purpose of draught. In all kinds of glass, except flint, these
openings are the only exit for the flames or heat into the cone, and the heat striking directly against
the roof or arch of the furnace, is reverberated down upon the pots, finally escaping through these
openings or working holes." This necessitates a great loss of heat, which is obviated in some degree
in the flint-glass furnace, where the exit is by means of a flue or chimney, the entrance into which is
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low down in the side of the furnace, 80 that the heat is compelled to encircle the whole pot before it
can escape.
The sides of the furnace are constructed of bricks, formed in moulds made for the purpose. The
best fire-clay, mixed with the remains of old pots coarsely ground, is the material employed for making
these bricks. No cement is employed in the arch of the roof; the expansion of the stone, and the par-
tial fusing of the interior surfaces afterwards, binds the whole sufficiently well together.
The pots.-These crucibles, or pots, are next in importance to the furnaces, and every care is taken
in their production. The best fire-clay, mixed with varying proportions of the remains of the old pots,
is employed, and the tempering, or previous preparation of the mixture, requires great attention.
By means of levers worked through different openings of the furnaces, the pot is brought into its
proper position, and is then "glazed," as it is technically termed, before being filled with materials;
2. c. some old glass is thrown into it, and spread over the sides in the melted state; this then penetrates
to the depth of a few lines, into the substance of the pot, and forms a hard, difficultly fusible glass,
which protects the pot from the further action of the materials.
Preparation of the materials.-It has already been stated that a great saving of fuel and time is
effected by intimately mixing the materials in the most minute state of division. The materials are
either mixed together in heaps, or, better, in the slowly revolving barrels similar to those employed in
the powder-mills.
Melting.-When the melting point is attained, the simply calcined or fritted mixture is introduced,
but not all at once. The mass of glass which a pot will hold, occupies before fusion, in the state of a
mixture, twice the space of the melted glass. One-third of the mixture is first introduced through the
working-holes, by means of shovels, and the other two-thirds are added successively, when the previous
portion appears thoroughly melted.
During the whole period of the melting, the stokers keep the furnace well supplied with fuel, 80 as
to prevent any portion of the grates becoming uncovered, since a rush of cold air from below would
probably split some of the pots from top to bottom. During this operation, the founders are engaged
in observing the progress of the fusion, by taking from time to time proofs, or drops, from the pots,
by means of a short rod, flattened at one end, and examining whether any undissolved grains of sand
are perceptible on cooling, and whether the mass, which still contains a quantity of air-bubbles, appears
uniform throughout. At the close of the melting process, the contents of the pot are not by any means
pure, or equally mixed. The solid matter is indeed all dissolved, but the mass of glass is full of small
bubbles of gas, presents a spongy rather than a dense appearance, and is not yet in a state fit for
working. The surface is also covered by a layer of so-called glass-gall.
2122.
S
i
i
W
A
A
i
i
S
Fining.-The last part of the process of glass-making is now arrived, which is termed the fining, and
the object of this is the removal of the air-bubbles and impurities, such as undissolved grains of sand,
&c., from the chemically finished glass, in order to prepare it for working. This process is a simple
separation of the beterogeneous substances by subsidence, in which the heavier particles settle down
to the bottom, and the gas-bubbles rise and disperse on the surface of the melted mass. During this
time, which always comprises several hours, no chemical change occurs, with the exception of the vola-
tilization of a little alkali; but the proofs drawn by the founder are much more uniform in texture and
freer from bubbles, until, at length, the whole is recognized as thoroughly fined. The mass of glass
which is now ready, can only be formed into vessels when it possesses a certain state of consistency,
109
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and this is entirely dependent upon a fixed temperature which has been very much exceeded during
this period. The working, consequently, does not immediately follow the fining process, but a period
intervenes, during which the heat of the furnace is allowed to sink to that temperature at which the
glass is in the best condition for working or blowing. Observations with Wedgwood's Pyrometer have
shown the proper temperature for working to be 70°.
Bottle-glass.-All kinds of hollow articles, as bottles, drinking vessels, preserving glasses, chimney
glasses for lamps. goblets, tubes, and chemical vessels in general, from the finest Bohemian glass for
cutting and grinding, to the ordinary green bottle-glass, are included under this head.
,
Glass furnace.-The arrangement of an ordinary glass furnace is shown in Figs. 2122, 2123, 2124,
and 2125. The figures represent a four-sided furnace, intended for six glass-pots, and when constructed
in an appropriate manner, can be used for all kinds of glass belonging to this class. Fig. 2122 rea-
2123.
e
e
e
t
m
772
u
resents a horizontal section at the height of the sieges or seats. Fig. 2123 a perpendicular section
through the teazing-arch. Fig. 2124 is also a perpendicular section through the sieges, and Fig. 2125
is a front view with a section of the fritting-kiln.
2124.
v
e
e
u
и
7
n
x
x
x
There are four side-kilns connected with the main furnace A, in the shape of four wings, viz. two
cooling or annealing furnaces B B, and two fritting-kilns CC. Above the foundation, in which the
drains xxx are excavated, the sole-stone w is placed, which forms the bottom of the fire-room. The
two fire-places and grates m m are situated above the ash-pits y, and are exactly opposite to each other;
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they are supplied with fuel from the arches bb and dd, whilst the flames from the two extremities
meet in the fire-room g, Fig. 2124, and enter together the space a a occupied by the pots uuuu, and-
reverberating from the four-sided arch-escape at last through the flues c, eight inches in width, into
the side ovens, of which two c c can be heated by separate fires kk; the damper S', Fig. 2125, shuts
off the flame from the furnace A when required. The uprights iiii separate the working spaces of
the glass-blowers, who obtain access to the glass in the pots through the working-holes e c. Imme-
diately below these are the openings r r, which can be opened for removing the pots, when broken or
worn out, from the sieges, to which they often adhere. In order to retain the heat in the furnace, the
2125.
Z
Z
S
working-holes are made as narrow as possible, and consequently much smaller than the pots; when it
is necessary to change the latter, they are removed through the side arches, of which there are two in
every furnace, and these are kept constantly bricked up, except when actually in use. Chimneys l are
sometimes erected over one or more of the working-holes to carry off the heat and the vapors from the
pots; these, however, are not essential, and are not often used. The side-kilns are accessible by the
doors SSS. Wood is placed on the scaffolding 22 to dry. The cupola or arch v is walled over with
ordinary bricks, and the corners are filled with sand and earth.
The round melting-furnaces, although very commonly used, are not so commodious as those of quad-
rangular form under the same circumstances.
Bottle-glass-Composition.-In choosing ingredients for this kind of glass, economy is the chief object;
color and appearance are here of no moment. The following examples are calculated for 100 lbs. of
sand.
For Champagne bottles
Ordinary green
English bottle-
according to Jahkel.
bottle-glass.
glass.
200 lbs. felspar.
72 lbs. of lime.
100 lbs. lixiviated ashes.
20 " lime.
280-278 " lixiviated wood-ashes.
40-
90
"
kelp.
15 " common salt.
30-
40
"
wood-ashea.
125 " iron slag.
80-100 " clay.
100 " cullet.
Mechanical operations.-The manufacture of bottles affords a good instance of the dexterous manip-
ulations which are practised in blowing glass. The most important instrument is the pipe," Fig. 2126.
2126.
c
This is a tube composed of wrought-iron, 4 to 5 feet long, 1 inch thick, and about t inch in the bore,
having R knob at each end, the one of which a serves as a mouth-piece, whilst to the other b the melted
glass is attached. To protect the workmen from the heat of the metal. a wooden handle c, about a foot
in length, surrounds the upper part. As soon as the working-holes are opened the workman attaches
as much melted glass to the end of the pipe b as he considers necessary for the production of a single
bottle. By dipping the previously warmed pipe into the pot, a little glass remains attached to b; after
turning this in the air before the hole, until it is cooled, and blowing slightly into it to render it hollow,
a fresh layer of glass may be attached to it in the pot; to this, a third is added in the same manner
until the ball at the end of the pipe has accumulated to a sufficient size. That this ball may become
uniformly tractable in the subsequent forming, it is held by the workman in the flame of the furnace
through the working-hole; it is then brought into one of the round concavities of the marver, (constructed
at different times from a stone, marble or cast-iron plate,) where the ball gradually assumes the form
of a pear-shaped vessel, Fig. 2127. It acquires this shape by the constant rotary motion given by the
workman to the pipe whilst the cooling and stiffening of the mass is rendered uniform by the marver,
and is prevented shrinking together by constantly blowing into the pipe with very little force. The
mass of metal (metal is the technical term applied to glass during working) must be equably dis-
tributed round the axis of the pipe, and advanced in front of its mouth, being connected with it only by
a short neck.
Thus far advanced, the glass has again become cool and is rewarmed by insertion into the working-
hole, in such a manner that the front part receives the chief portion of the heat and becomes the
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GLASS.
softer. The pear-shaped vessel is now lengthened by the blower, and its form is approached to that
of a bottle by a threefold operation; by blowing into the tube with greater force, by swinging
(backwards and forwards, in the manner of a pendulum) and by a simultaneous constant rotary motion
of the pipe round its axis. The globular form which the glass tends to assume under the influence
of the blowing, is converted into a long thin egg-shape by
the swinging motion, Fig. 2128. The rotation round the
2127.
2129.
axis of the pipe is an essential part of every operation in
glass-blowing. The glowing mass of glass creates a power-
2128.
1
ful current of air in an upward direction, and the lower
portion becomes cooled in consequence much more than the
upper. This naturally creates an inequality in the resistance
offered to the blowing, and the upper portion would be more
expanded than the lower if the cooling influence were not
allowed to act upon all parts of the surface alike by the re-
volving motion of the pipe, and this is particularly the case
when the pipe has to be held in a horizontal position. The
mould a (a simple cylindrical hollow block of wood or iron) is
d
placed at the side of the workman who is blowing the pear-
shaped vessel into this he inserts the vessel as soon as it
has acquired the proper thickness, in the manner represented
at Fig. 2129, and by blowing forcibly into the tube, he presses
the glass firmly against the sides of the mould, whilst, by a
kind of jerking motion, the neck is drawn out to the proper
length. The unfinished bottle is again warmed in the work-
ing-hole in such a manner that the lower part only is heated,
whilst the other parts remain comparatively cool. In the mean time, another workman or a boy has
attached a small quantity of glass to another pipe or rod of iron, called the punty, which is also kept hot
in the working-hole. Both workmen now stand opposite to each other; and whilst the pipes are kept
constantly turning, the punty is forcibly pressed against the middle of the lower part of the bottle which
is thus forced inwards, and an even edge is produced, upon which the bottle may stand steadily. The
bottle remains for some moments between the two instruments, Fig. 2130, until, by the application of
cold iron or a drop of water, the neck can be
separated from the pipe. This sudden separa-
2130.
tion is an operation of constant recurrence in the
glass-house, and is effected by a sudden change
a
(c
of temperature produced at the point of separa-
tion in the hardened glass, either by the cold
application of a drop of water, or by the powerful
heat of a red-hot iron or thread of liquid glass from the pot. The point of separation must often be re-
heated in order to fly on the application of cold water. The bottle is now supported by the punty, as
shown at a, Fig. 2130, so that the neck can be warmed. and the sharp edges melted round without
softening the other parts. A rotating motion is now given to the red-hot neck, the pipe being rolled
backwards and forwards upon the knees of the workman. The rim for strengthening the neck is formed
from a drop of glass taken from the pot by the edge of the flask and wrapped round the mouth in the
form of a thick thread. The bottle, which is now finished, Fig. 2131, is immediately carried by the
punty-rod to the annealing-oven by a boy, pushed into its proper place, and the punty-rod is
lastly detached from the bottom of the bottle by a sudden sharp jerk. The place where the
2131.
punty was attached is perceptible in every bottle blown in this manner by the sharp edges
where the fracture occurred.
Large round bottles are blown without the use of a mould, and when of very large size,
like the carboys for sulphuric acid, the aid of steam is called in, by spirting a mouthful of
water into the interior, and holding the mouth of the pipe with the thumb.
Attempts have consequently been made by many inventors to furnish the bottle-maker
with a mould of such construction as would enable him to secure the formation of a bottle,
perfect both as regards form and capacity, at one single operation, without reliance upon
his own correctness of sight. The use of moulds of this description, like that of Rickets, which
is easily managed, affords a great saving of time, and renders the repeated heating of the
bottles unnecessary.
The mould consists of a body which forms the belly of the bottle and of four other parts,
a fixed bottom-piece with a movable piston for forming the concavity, and two movable
pieces for the neck. Two treadles set these different parts in motion. As soon as the work-
man has introduced the hollow lengthened globe into the belly of the mould, by pressing
with his foot upon the first treadle, be brings up the neck-piece, then forces the glass into
contact with all parts of the mould by a powerful blast, and finishes the bottle by working
the second treadle which forces the pestle against the bottom. On the removal of the pipe,
the rim of the neck is all that remains to be perfected.
Champagne bottles require to be made more than usually strong in consequence of the
pressure exerted by the carbonic acid enclosed within them, and they are particularly liable
to fracture during the bottle-fermentation of the wine. Yet they will often withstand a pressure of 40
atmospheres, and upwards, (= 600 lbs. on the square inch.)
Crown-glass.-The purest and most beautiful glass is the white crown-glass," manufactured in the
Bchemian glass-houses for grinding and polishing. Intended for articles of luxury and art more than
for the supply of the ordinary wants of life, the purity and absence of color in the mass is naturally
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heightened by the grinding and polishing, and is combined with an elegance of form which would be
thrown away upon a less pure material. Glass, for the purposes of the grinder, is better prepared by
the use of proper moulds than by simple blowing, partly because the forms are frequently not 80 simple
as to admit of their being made by hand, and partly because the various grooves and projections upon
the surface can be roughly given by means of a mould without adding to the difficulty of blowing, and
time and trouble is thus saved in the laborious operation of grinding. The moulds and the mode of
using them resemble. in every respect, those which will be described under flint-glass or crystal.
Windoo-glass-Properties-Although window-panes may be made from any kind of bottle-glass
that is not too much colored, just as many articles of bottle-glass are actually prepared from window-
glass; yet, with reference to the object in view, a very marked difference is made in the mixture of
ingredients. The amount of lime in the mixture must not be too small, that the panes may not be sub-
ject to become opaque when exposed to the atmosphere, whilst, on the other hand, any composition
that has a tendency to devitrification would be a serious evil, as the glass has to be successively heated
a great many times before it acquires the proper form for window-panes.
Production of window-glass.-The mechanical production of window-glass is effected with the pipe,
either by blowing a hollow cylinder, which is cut open and flattened out, in a special operation, (sheet
or broad glass,) or by distending, with the aid of centrifugal force, a more globular-shaped vessel
attached directly to the pipe (crown-glass.)
Sheet-glass.-Cylinder-blowing.-The operation of blowing cylinders commences as usual with the
collection of a sufficient quantity of metal from the pot at the end of the pipe. A massive glass ball is
thus attached round the nob of the pipe which must be pushed forward with a flatting-iron until an
annular groove is produced as at a. This operation completed, the blower rounds the ball on the
marver, and distends it slightly by blowing. It then assumes the form represented in Fig. 2132, from
which it will be seen that the mass of glass is thickest in front, as from that part it has to be distended
and lengthened into a cylinder. In the subsequent operations, it first assumes the width of the future
cylinder and then the length. With this object in view, the workman, after having rewarmed the ball
of glass, holds it perpendicularly above his head, and blows into it. The heavy bottom yielding with
less ease to the blast, admits of the distension of the width, and a flattened bottle is formed, Fig.
2133. As soon as the proper width is attained, the pipe is quickly inverted, so that the ball is under-
most, and an incessant swinging motion is then kept up with a constant blast. Further distension is
thus effected, but from the bottom only, as the thinner sides have by this time cooled, and in conse-
quence of the swinging motion in the direction of the length, so that the bottle acquires the form repre-
sented in Fig. 2134, by the time that the glass has so far cooled as to be no longer expansible. If the
swinging were admitted, the bottle would be distended in all directions, and present the form indicated
by the dotted line. By repeated warming, swinging, and blowing, the form Fig. 2135 is gradually pro-
duced, which is then the proper length of the cylinder. It is then conical. and terminated by a semi-
circle, in the middle of which, at c, is the thinnest part of the vessel. When the workman blows air
into the pipe, and closes the aperture with his thumb before withdrawing the pipe from his mouth, the
air expands and exerts great tension upon the sides of the cylinder; if the weakest part, at c, is now
held in the flame it will be blown out and burst. The cylinder having thus been opened as represented
in Fig. 2136, the next object is to extend the somewhat uneven and thick margin of the aperture, and
reduce it to the proper dimensions, whilst at the same time the other parts are straightened and acquire
a uniform diameter, as is shown in Fig. 2137. Prominent portions which may sometimes project, are
cut away with the scissors.
2135.
2136.
2137.
2134.
2132.
2133.
o
According to the size of the cylinder, it may be either blown at once, or it will require to be reheated
several times. When very long and wide cylinders are blown, the lower portion is liable to become
too thin; an extra portion of glass must then be incorporated with it before the opening process.
The neck and curvature where the pipe was attached to the cylinder have now to be removed, in
order to spread the whole out in the form of a plate, and the cylinder must be cut open lengthwise.
The cylinder. supported by an assistant upon a wooden rod, is, therefore. turned round two or three
times in the curve of a bent iron, heated to redness, as shown in Fig. 2138, and a drop of water is
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GLASS.
allowed to fall upon the heated line, which fractures the glass and detaches the cap. In a similar
manner, but in a straight direction, a crack is made longitudinally, and the cylinder is then prepared for
spreading or flatting, Fig. 2139.
2138.
2139.
Furnaces constructed purposely, in separate buildings, are necessary for this operation, the principal
parts of which are shown in horizontal section over the sole in Fig. 2140. The arched space A which
extends the whole length of the furnace, comprising the ash-pit a, and the grate r; the former is
accessible by the door b, the stokage is performed through d. The flame enters the upper space
through the apertures cccc, and first plays upon the flatting-hearth C before entering the annealing or
cooling furnace B, which is also heated directly by the fire, when it escapes through the flue or channel
D, by which the cylinders are introduced to be subsequently removed at i. The flatting-hearth and the
cooling-furnace are connected with each other by a low-arched, wide aperture E, for the passage of the
plates, as well as by a smaller, higher opening g, for the admission of the flame. The heat in the in-
terior can easily be regulated by pushing plates over the apertures c c, and opening or closing the
aperture k. The flattener stands in front of the aperture l, the workman engaged at the cooling-furnace
before m, and an assistant in front of i, who pushes the cylinders 000 o along the railway p.
2140.
,
S
c
s
c
c
B
q
C
c
m
The most essential part of the furnace, however, is the spreading-plate or flatting-stone q and -
This must be perfectly even, without any roughness or inequalities which would scratch the glass or
make it lumpy; it must be inalterable in the fire, and of a size somewhat larger than the flattened
cylinders. A plate of this description is usually manufactured from fire-proof clay mixed with cement,
(either ground fragments of burnt clay of the same kind, or fine sand, or ground quartz) strongly
beaten during drying, then burnt, and lastly ground smooth; it is laid upon a bed of sand and in con-
tact with a second table of the same sort in the cooling-oven. To make quite sure that no injury shall
be sustained by the plates upon the flatting-stones, it is customary to cover this previously with a
Lager. This is the name given to a thick plate of glass expressly blown for this purpose. These
lagers are soon devitrified, which is of no moment, 80 long as the surface remains smooth; this, how-
ever, does not last long, and frequent renewal of the lager becomes necessary. Lastly, to prevent the
cylinders from attaching themselves to the lager, the flattener, in some manufactories, throws a handful
of lime into the furnace, which is carried as fine dust by the flame and spread over the lager. The
temperature in the flatting-furnace must only be just sufficient to soften the cylinders; whilst in the
cooling-furnace it must not attain that point.
The spreading operation is commenced by introducing the cylinders into the warming-tube D. The
further the cylinders are pushed forward by those succeeding them the more they become heated, until
they begin to soften on reaching the flatting-stone. They are then taken by the workman with a
rectangular bent iron, and placed upon the lager with the cut side uppermost, where they open of
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871
themselves, and are easily straightened and made even. For this latter purpose, a rod of iron, furnished
at the end with a wooden polisher, Fig. 2141, is employed, and this is dipped into water each time it is
used. When all the curvatures and lumps
have been reduced, the sheet is pushed back-
2141.
wards into the annealing-oven, where it cools
down and is placed in an upright leaning po-
sition by another workman. Between every
30 or 40 sheets, an iron rod s 8 8 is inserted, and
the operation is continued until the whole fur-
nace is filled.
Fig. 2142, 1 is an elevation of a flatting-
furnace in section, with three annealing-arches of the ordinary description.
Fig. 2143, 2 is a ground plan of the same.
Fig. 2144, 3 and 4 are elevations of two end views of the flatting-furnace. a b is the spreading-furnace
divided into two compartments by the partition c; dd are two sets of fire-bars, on which wood must be
burnt; e is the spreading or flatting stone of the furnace, which must be perfectly smooth and even; i
is an opening through which the cylinder is placed in the furnace previous to being laid on the flatting-
stone e; h is the opening through which the workman spreads the cylinder into a flat sheet of glass;
f is the opening through which the sheet of glass is removed to the table or bed g, in the compartment b.
The upper side of the table g is made of stone, similar to that employed as the flattening surface. It is
fixed to an iron frame-work on wheels, and is kept at a proper degree of heat by remaining in the
furnace, as shown in the drawing. The carriage runs on a railway in front of the annealing-arches,
where the sheet is transferred in the usual way.
2142.
1
a
The cylinder is placed on the flatting-stone, and is split lengthwise by passing a red-hot iron bar k
from end to end, having previously sprinkled a little charcoal powder on the inner surface of the cyl-
inder. It is now spread out into a sheet by pressing the same on the flatting-stone, by means of a
small block of elder-wood, fixed on an iron bar m. The temperature at which the flatting is performed
is such, that the operation does not occupy more than a minute.
2143.
2
a
e
Two improvements have been introduced in this operation. One consists in making part of the floor
of the compartment a to consist of a movable stone about 10 inches in diameter, on which the cylinder
is placed. It is gradually exposed on all sides to the action of the fire, by causing the stone to revolve
on its axis, and thus the objection to the previous plan is avoided where one side of each cylinder
became so much hotter than the other.
2144.
3
m
Crown-glass.-In the manufacture of crown-glass, in circular disks, a flattened vessel is first blown in
front of a furnace specially constructed for the purpose, and this is converted, without any interruption
of the process, into a round disk, thickened in the centre.
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GLASS.
Figs. 2145, 2146, and 2147 show a ground plan of the melting-furnaces and the elevation of an end
and side; aaaa are the stone pillars which carry the cone; 6666 the walls of the furnace; cc the
grate-bars upon which the fuel lies; dd the "sieges," or position which the melting-pots occupy, one
opposite each opening eee; g is an elevation of the sides ff; and h an elevation of the ends ii of the
furnaces; kk k are temporary openings to enable the workinen to insert large iron levers to assist in
placing the pots, which are carried on a machine, in a red-hot state, into the furnace through the
other temporary opening 1.
2145.
a
a
b
b
i
b
b
a
2146.
2147.
th
e
l
g
k
k
k
When a certain weight of glass, a, Fig. 2148, has been collected or gathered from the pots on the end
of an iron tube b, it is fashioned into a peculiar form, as shown in the figure, on a solid plate of cast
iron c, also called a marver, although used for a different purpose to that mentioned previously. Pre-
vious to the operation of marvering," the workman cools the iron
pipe, which has become heated by being exposed in the melting-
furnace.
2148.
The marver c is placed on rollers for the convenience of moving
it from place to place as required. When the mass of glass
has assumed the proper form, a boy blows through the iron
b
tube, while the workman continues to roll the ball upon the
marver.
During the previous operation of "marvering," the mass of glass
is fashioned so as to give the outer extremity a conical form, the
extreme end of which becomes the outer axis of the globe during
X
the operation of blowing. This outer axis is called the 'bullion,"
and during the expanding of the globe, the workman rolls this
X
bullion along a straight edge.
The piece of glass, after the above operation, is reheated, in the blowing-furnace, and expanded by
the workman blowing through the iron pipe, until it is so far cooled as to require another 'heat." When
it has been blown to the proper size, Fig. 2149, 2, it is again exposed to the heat of the furnace, when
the workman, resting the pipe on an iron support, during which time the neck remains cool, causes the
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GLASS.
873
glass globe, by a peculiar motion of the pipe, to assume the shape shown in the figure, 3. This last
operation is technically termed 'bottoming the piece." It is then removed to a framing, Fig. 2150,
where it rests on its edge on some ground charcoal and cinders a. Another workman then attaches a
strong iron rod with a quantity of melted glass at its end, to the centre of the piece, as at b. The
" blower" now touches the neck of the piece at c, with an iron rod previously dipped in water, and by a
smart blow on the iron tube d, detaches the piece, leaving the neck open, as shown at 4.
1
2149.
2
3
The " piece" is now removed to the flashing-furnace." The thick neck is first heated at the opening,
whence a powerful flame is issuing. Fuel is placed on the grating for the purpose of warming the
" piece," while the neck is heated from the larger furnace through an opening in the side. As soon as
the neck is sufficiently soft, a boy inserts a flat iron tool through the nose-hole, to smooth the roughness
left in the neck by breaking it off as described above.
When the neck has been sufficiently heated at the nose-hole, the bell-shaped vessel is brought in
front of another opening, where it receives the full heat of the flame, and the pipe is then made to
revolve with the greatest possible rapidity. The action of this rotary motion upon the softened glass
is easily conceived. The centrifugal force communicates to the particles of glass a tendency to fly off
at a tangent, and to arrange themselves in a circular plane perpendicular to the axis of rotation. The
mouth being the softest part, first expands, and this quickly increases until the whole suddenly opens
into one sheet of glass, Fig. 2151, of about 6 feet in diameter, which, with the exception of the central
2150.
2151.
b
portion, is of nearly uniform thickness. It is obvious that a sheet of such dimensions must quickly fold
together in the soft state, if the rotary motion is not kept up. The workman, therefore, continues the
rotation after the removal of the sheet from the flame of the furnace, until it reaches the annealing-oven,
where it is placed on a small circular bench, and is detached from the rod by means of a pair of strong
shears, leaving a mark called the bullion," or bull's-eye. Another workman, who has charge of the
annealing, now raises the table" of glass upon a large fork-like instrument, and carries it to an upright
position in the annealing-arch, Fig. 2152. The tables stand thus on their edges, upon two strong parallel
iron supports, which run the whole length of the annealing-kiln.
2152.
a
The glass, after remaining in the kiln for a considerable timo, during which the cooling has been
carefully regulated, is withdrawn, so as to enable a workman to go inside and hand out each table on
the outside to an assistant.
Plate-glass.-The operation of blowing and flatting glass for mirrors is similar to that already
described for window-glass, with some slight modifications rendered necessary by the greater size of the
plates. The casting of plate-glass is a perfectly distinct operation.
The thickness of these plates, which are often 10 feet and more in length, must of necessity corre-
spond with their extension and that the light may be perfectly reflected from the metallic surface at
the back, they must be as transparent and colorless as possible. To conform to such important con-
ditions, the composition must consist of the purest ingredients, and afford a glass, the surface of which
is quite unalterable when exposed to the air; if this is not the case, the plate becomes dull, loses its
polish, and with this its transparency.
110
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The following drawings of a plate-glass furnace exhibit the manner in which the fusing-pots are
arranged, and also how they are inserted and removed. Fig. 2153 is a horizontal section at the height
of the sieges to the right of xy, and somewhat lower to the left, through the holes for the cuvettes.
Fig. 2154 is a perpendicular section through the line x y. The melting-furnace is surrounded by four
side-furnaces aaa, used for burning and heating the pots, and 80 arranged that the whole length
2153.
m
m
m
0
i
i
0
a
B
B
x
a
n
n
of the sides with the siege a is left open and free of access. Thus the two remaining sides are only
accessible by the narrow passages B B, and these are connected with the large apertures bb. These
apertures are used for the insertion of the pots c, and, at the same time, for stoking the fire; for the
latter purpose they would be too large, and allow too much heat to be lost; they are consequently
bricked up above and closed in front by slabs of clay, with the exception of the small apertures e c. À
grate is indispensable when coal is used, but this is not the case when wood is the ordinary fuel.
2154.
B
B
SU
n
a
T
S
s
The flame travels from the melting-furnace, after passing between the sieges, and heating the pots cc,
and the cuvettes i, through the flues 00 into the side-furnaces A. Two rows of holes are left in the
free sides of the furnace. By means of the upper working-holes m m m, the melting-pots are accessible
for the purposes of ladling; through the two lower holes nn, the cuvettes are inserted or removed upon
the iron slabs pp, which must consequently be exactly upon the same level as the sieges. All the
holes can be closed by movable plates at pleasure. The draught can be regulated through rr, and
the ash collects in 8 8.
Mr. Bessemer has lately proposed a new method of casting plate-glass in sheets, by pouring the glass
in the melted state directly from the pots between two rollers, placed at a certain distance from each
other. so as to ensure a uniform thickness throughout. This is an invention which must commend itself
to many in our country, as this art is but young even in England, and scarcely known here, but which
must yet be extensively manufactured, as the means are not wanting, and the material is abundant in
many of our states. At present our valuable plates are imported, and Germans are the artisans that
are mostly employed in England. There are plenty of them in this country, and doubtless many good
artisans capable of managing this business.
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The pot-furnace and machinery for this process are entirely novel and very different from those in
common use, and as the invention is likely to be carried out in practice, a notice of the most important
parts of Mr. B.'s patent will not be out of place here. The furnace employed is a reverberatory furnace,
Fig. 2155, with a low arch and descending flue d The flame proceeding from the grate a, plays upon
the surface of the materials in the pot e, in the fire-space b. The arch is formed at that part which is
most exposed to the heat, and the alkaline vapors from the mixture, of hollow bricks ccc, over which a
draught of cold air is caused to play, by connecting the space above the furnace with the ascending
main chimney. The object of this cooling, which is of course attended with a loss of heat, is to prevent
2155.
etlel
0
a
//////////
d
tears, consisting of the fusible product of the action of the alkaline vapors upon the ingredients of the
bricks, from forming on the arch, and falling into the glass during fusion. The pot, c, is of very large
dimensions, as large indeed at the lip on the one side as the width of the plates, which it is proposed to
cast with it. It is set upon a siege composed of large masses of fire-stone, and these are cemented to-
gether, as well as the pot upon them, by some bottle-glass, which, in the fused state, enters the crevices
and binds the whole firmly together upon the strong-ribbed cast-iron frame g.
This frame moves upon four wheels h upon a railway to, which extends beyond the furnace to the
rolling machinery, to be described immediately. Thus pot, siege, and frame are all wheeled in and
out of the furnace at once, as will be seen
2156.
by reference to the section, Fig. 2156, where
jj represent the hollow bricks, or masses
of stone, by the removal of which a free in-
gress and egress is allowed the whole car-
riage on the continuation of the rail. The
pot and carringe fill the entire recess in the
b
furnace, and the flame playing upon the top
does not much affect the iron frame of the
carriage through the bad conducting-stones
which form the bed of the pot. Fig. 2157
is a longitudinal section through the middle
of the frame-work and machinery, by means
of which the pot and siege are raised, and
the melted glass poured out between the
rollers.
The carriage consists of a strong-ribbed
iron frame, mounted on four small flanged
wheels which run on two rails. The
upper side has a recess into which blocks
of soap-stone, or fire-brick, are fitted into
an iron frame. In the upper part of these blocks recesses are made for the melting-pots to sit snugly,
and a quantity of broken bottle-glass is laid on the top of the blocks, and they are heated till the
glass melts and cements the joints of the blocks together, and while this glass is yet in a fluid state,
the carriage is removed a moment from the furnace to receive the melting-pot which is brought in a
white-heat from the pot-arch, set in the midst of the fluid glass. and the carriage then returned to the
furnace. On afterwards using the pot, as the bottom is very thick and the heat only having access to
it through the materials which it may contain, the bottle-glass used to cement the pot to the bed or
recess is found not to be too cold to be brittle, nor 80 hot as to allow the pot to slip from the carriage.
Fig. 2158 is a side elevation of the machine, with the pot and carriage in their position after being
removed from the furnace.
Fig. 2157 is a longitudinal section showing the pot in an elevated position and partly emptied.
Fig. 2159 is a longitudinal section of one of the rollers and stuffing-boxes, showing how the water is
made to enter and leave while they are in motion. aa is a side framing of cast-iron secured by
the cross-pieces c, and also by the stretchers ec, between the side-frames a a. The rollers f and g
are placed in suitable bearings fitted to the side-frames, and are made to move to and from
each other by means of screws, which force the brasses H and roller f near to the roller g. A
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GLASS.
piece of iron is placed between the brasses and the frame, and according as it is exchanged for
one of more or less thickness so will it cause the rollers to be nearer or further apart, and thus
regulate the thickness of the glass. The roller f is also provided with wheels jj at each end, and
the roller g also with wheels at each end within the side framing. In addition to these wheels,
the axis of the roller f has on the outside of the framing a large bevel-wheel m, driven by a pinion 90,
2158.
$
C
X
on the end of an upright shaft p, driven by an underlying shaft from the main driver. The upper
part of the shaft p is supported by a bracket q, projecting from the side-frame; near the upper
part of the framing there are two plummer-blocks r, which form a support to the pins which project
from the side of a piece of tilting-frame. There are two of these pieces t, one on each side of the ma-
2157.
K
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cch
or
chine, and they are connected together by a third piece u, by bolts. The frame when thus put together
is supported by pins 38, and occupies nearly the entire width between the side-frames a a. The lower
part of the piece 1 has a segment of a tooth-wheel formed on it and centred on the pins 8, so that the
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GLASS.
877
tilting-frame may move a portion of a circle on these pins. The piece и has two small ribs or rails
extending across and cast upon it, which form a continuation of the rails which conduct to the furnace.
X is a shaft extending across the frame supported by plumber-blocks y, attached to the side-frames e,
which shaft x has pinions z upon it geering with the segment of the tilting-frame t. The shaft x is also
elongated to a convenient distance, and supported at its extremity by a frame of two side pieces con-
nected by stretchers. The upper part of the frame carries two plummer-blocks and a shaft the shaft
having a handle and a pinion upon it, which geers into a large spur-wheel on the shaft X. By turning
round the handle on X it forcibly raises the tilting-frame with any object that may be placed on it.
There is an opening in the tilting-frame through which the axis of the roller g passes; and this roller
is sufficiently long to allow the required movement of the tilting-frame. The rollers are supplied in
this machine with water to keep them cool; the water is conveyed below the floor to the pipe 1; at 2,
there is a branch which leads off from 1 to the axis of the roller g, which it enters through the stuffing-
box; the tube 1, proceeding further upwards, bends over and forms another stuffing-box 4, which allows
the upper roller f to move a small distance horizontally, to alter the thickness of the plate. The water
2159.
I
enters the axis of the roller f by passing through the stuffing-box 5; the axis of the roller is not hollow
throughout, but the hollow part of it terminates at 6, Fig. 2159, where there are two side holes bored
at right angles to it, which allow the water to pass into and occupy the large hollow space in the body
of the roller. By a similar contrivance the water is allowed to flow out of the opposite end of the
roller, passing through the stuffing-boxes 8, 9, and, descending the pipe, is conveyed away under ground.
A strong curved plate K extends the entire width between the said frames, fitting closely up to the
roller g, and secured to the frames by lugs. On this plate the sheets of hot glass slide down towards
the flat ted, but which is broken off in the cuts; the side of the melting-pot nearest to the machine
has a curved lip, so as to overhang the roller g nearly as far as the centre. The pin 8 of the tilting-
frame is at its centre a little above the upper side of the roller g, so that the lip of the pot being in the
position shown in Fig. 2157, it does not shift from that spot far, as it may be tilted up.
The mode of operating with this apparatus is as follows: When the glass is in a fit state for casting,
the dccr is removed by a crane from the mouth of the furnace, and by the assistance of an iron hook
the carriage and its pot are easily rolled forward upon the rails before mentioned to the tilting-frame t;
then they occupy the position shown in Fig. 2158. The carriage and its pot are now moved forwards
until the set screws M come in contact with the carriage the office of these screws is to regulate the
extent to which the lip of the pot shall overhang the roller g, 80 that when a new pot is used its proper
position for pouring may be adjusted. The screws M pass through stout lugs N, cast on the piece ";
the handle on X being turned, the pot will be elevated, as shown in Fig. 2157, when the glass passing
between the rollers will be formed into sheets. When the pot is emptied it is again lowered and re-
turned to the furnace for a repetition of the preceding operations; the roller f is furnished with a rib
on its circumference, which is the whole of the roller; this at each revolution cuts the glass off into
lengths.
Lead or flint glass (so called because flint was first employed in the manufacture) is peculiarly
adapted for articles of luxury, such as goblets, chandeliers, decanters, &c., from the ease with which
it is ground or cut, from its brilliant lustre, high refracting power, and perfect freedom from color.
The mass which is used for this purpose is called, in a more limited sense of the word, crystal,
(from its resemblance to rock crystal,) and it excels the Bohemian grinding-glass (crown-glass) with
reference to refractive power and easy fusibility, although the latter is harder and more completely
colorless.
As nearly all the articles composed of flint-glass, or crystal, require to be ground, in order to exhibit
their greatest brilliancy, they must be constructed in a very massive form; there is consequently more
necessity for avoiding all sources of color, and for preparing the glass from oxide of lead, potash, and
silica alone.
The fusion occupies six or eight hours, and the fining, which is very much facilitated by the easy
fusibility and the purity of the materials. requires about the same time.
During working, the glass must be protected from the smoke of the furnace, and iron must not be
brought into contact with it, as it otherwise infallibly becomes of a dark-brown color. Iron is dissolved
by the glass, taking the place of the lead, which separates as metal in the most minute state of division.
The construction of furnaces and melting-pots in manufacturing flint-glass are somewhat different
from those employed in the other descriptions of glass.
Fig. 2160 is a ground-plan of the melting-furnace; CCC are the pots which are situated at equal
distances between the pillars or piers E E which support the exterior dome. a a are the openings in
two of the piers for charging with fuel.
Fig. 2161 is designed to show how the heat is carried round the pot in its exit from the furnace. The
pots are covered with a hood-shaped top, and these fit the working-holes of the furnace, 80 that the
smoke and heat cannot escape in the same way as in the usual glass-furnaces ; a is the pot with the top
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GLASS.
b; c is the roof of the furnace; d the "siege" on which the pots are placed; and e e a flue, low down,
which passes between the furnace and the cone till it reaches a point f where it enters the cone itself;
g, Fig. 21614, is a front view of the pot and arch of the cone,
which allows the workmen to approach the opening in the fur-
nace, against which the mouth of the pot is placed; h is an
opening direct from the outside into the flue, for the purpose of
2161.
keeping it clean.
Fig. 2162 is a general view of the melting-furnace, cone,
0
2160.
a
E
c
c
e
F
c
c
a
c
c
21614.
E
c
c
and working-holes. It consists of two domes, AA, B B, one within the other, of which the interior
one is flat, and. the exterior of considerable altitude, terminating in a high chimney. The only connection
between the domes is by the flues G G, which are situated one on each side of the crucibles, 80 that
they receive the whole body of the flame as it passes from the fire-place to the exterior dome, and
thence to the chimney.
2162.
2163.
B
B
G
G
G
G
Z
G
x
x
Z
a
F
Flint-glass is either formed by simple blowing with the pipe, by blowing in moulds, or by moulds
alone; in every case the form can be improved, as is generally done, by grinding, &c.
The moulds are carefully constructed of brass or iron, and are somewhat wider at the upper part,
when of simple construction, that the pieces may be easily removed, or are composed of more than one
piece when projecting parts are to be moulded. A mould of the latter description is represented in
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879
Fig. 2164, intended for a decanter; a section of the mould is shown in Fig. 2168. The bottom e and
the sides a of the body form the lower and larger part of the mould, and are held together by the
screws the upper smaller part consists of two halves, meet-
2164.
ing in the line zz, which open after the fashion of a pair of tongs
when turned upon the hinge That they may not be extended
h
more than is necessary, the two wings are impeded by the plugs
o fixed to the ring i. The workman introduces the glass globe
g, attached to the pipe, into the body of the mould, the neck
portion being thrown open, and blows with great force into the
m
globe, as soon as the neck portion has been closed by an at-
0
tendant, and fixed by the screw m, (the female screw belonging
i
to which projects at n.) The glass is now forced, by the pressure,
n
against the sides of the mould, and extends in the form of a cap
at g, above the margin, where the pipe is detached in the direc-
tion of x x. The cylinder 1, and another similar one, more at the
back, are intended for the insertion of wooden handles. Massive
pieces, such as plates, are formed by pouring melted glass between
two plates of metal composing the mould, and the excess of glass
is squeezed out from the crevices by applying weights to the
mould.
All articles of fliut-glass, whether blown, moulded, or pressed, require annealing previous to cutting
or grinding, and as they are frequently constructed of very different thickness, two kilns, which can be
heated to different temperatures, are requisite; the larger and thicker pieces require that the kiln
should be much hotter than is necessary for thinner pieces. These kilns are long, low buildings, arched
over on the top. The various articles are all placed on sheet-iron trays. These trays are put into the
kiln, through the opening in front, and are all connected together by hooks, by which means they can
be moved by a chain, worked by windlass or similar machinery, to the further end of the kiln, and are
thus gradually withdrawn from the hottest part, and, having arrived at the further extremity, are re-
moved at a temperature little above that of the atmosphere.
Moulded or pressed glass never exhibits its full amount of lustre, nor even the degree of sharpness
of the metallic mould the glass, which is never limpid in its liquid state, is first cooled by contact with
the metallic surface, and is thus prevented penetrating into the sharp corners of the mould, nor does it
even accommodate itself perfectly to the flat sides. For this reason, the surface of moulded glass is
not even, but always more or less curved, and the edges are not sharn; but the use of moulds as a pre-
paratory step to grinding, is of great advantage to the grinder, as the vessel acquires a perfectly regular
form, and, although in a crude state, presents all the prominent and receding facets to be perfected at
the lathe.
The ordinary utensils used in grinding or cutting glass, are disks of iron, sandstone, or copper, which
revolve in a kind of lathe; their edges, which are sharp, angular, or rounded, are supplied with sand
for rough grinding, and with emery for fine grinding. Similar disks of tin, wood, or cork, used with
pumice-stone or colcothar, are employed for polishing the glass. It is obvious that not only disks with
very different edges will be required, but also disks of very different dimensions, from 8 to 10 inches in
diameter, (I to t of an inch in thickness.) For inscribing initials, designs, &c., disks of copper of the
size of a cent are employed, with oil and emery; the finest incisions are made with copper pencils,
either pointed or ending in a button or small disk.
Bessemer has lately taken out a patent in England (1848) for the manufacture of plates, sheets, and
panes of glass, which is of sufficient importance to merit a place here in full.
This invention relates, first, to the arranging of machinery for washing, drying, and sifting sand, and
afterwards grinding or crushing the same in combination with the other materials employed for making
sheets, plates, or panes of glass. Secondly, to the employing an additional pair of rollers to the ma-
chinery now used to roll glass into sheets. Thirdly, to a method of heating annealing-kilns or lears.
Fourthly, to a method of smoothing or polishing plates, sheets, or panes of glass, whereby an endless
belt or strap (charged with polishing material) is made to pass rapidly in contact with the surface of
the glass, and to traverse slowly across it in a direction at right angles to the line of its quick motion;
and lastly, to a method of producing plates or tables of glass of the description known as crown-glass,
in such a way that the centre of the table shall not have a bullion or knob as usual. First, with re-
gard to the method of washing, drying, and sifting sand, and afterwards grinding or crushing the same
in combination with chalk, alkali, charcoal, or other matters used for making sheets, panes, or plates of
glass. To accomplish this object, the patentee uses the apparatus represented in Fig. 2165, a longitu-
dinal section of the apparatus; Fig. 2166 a longitudinal or side elevation, and Fig. 2167 a plan of the
same. The letters of reference denote the same parts wherever they recur in each of the figures. A,
is a cylindrical iron vessel, having an annular trough or channet formed around its upper edge at A';
this channel is strengthened by brackets A", and has a flange at its upper edge A3, to which the mouth
of the vessel B is attached by bolts; this mouth-piece has three arms B', B', and B', meeting in the
centre boss C, which is bushed with brass, and so shaped internally as to form a bearing and support
for the shaft D, which has a conical collar at D', resting in the brass bush C, to prevent its dropping
downwards. As the lower extremity of it has no support, the bush C is elongated upwards so as to
form an oil-cup, and is covered by the piece C', which revolves upon the shaft, and prevents any sand
from falling into the oil. The shaft D passes upwards to any convenient height, where it turns in other
bearings, and has keyed upon it a bevelled wheel, into which are geered two other bevelled wheels,
mounted on a shaft proceeding from any first mover. The office of these wheels, but which are not
shown in the engraving, is to communicate a rotatory motion to the shaft D, in either direction, by the
shifting of a clutch in the manner well understood and practised in reversing geer. The shaft D is
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GLASS.
provided with a number of radiating arms or blades E, placed at such an inclination as to form each a
portion of a spiral, and will therefore have a tendency when revolving in one direction to lift any mat-
ters they may be moving among, and also have a tendency when revolving in the opposite direction to
press such matters downwards. F is a pipe to convey water from an elevated reservoir into the lower
part of the vessel A; this pipe is provided with a cock at F' and handle F.
In Fig. 2165, it will be seen that the vessel A and its mouth-piece B, although screwed together at
the outer flange A', do not come in contact at A', whereby a circular space or opening is left all round
the vessel, communicating with the trough A'. The action of this part of the apparatus is as follows
The sand to be used for making glass is conveyed along the floor G, of the upper room, and emptied into
the vessel A, until the vessel is at least two-thirds filled; the shaft D is then put in motion in the di-
rection to lift the charge; at the same time, the cock F' is opened, and water is allowed to flow upwards
through the body of sand, while the blades E keep lifting and turning it over. As soon as the water
R
M
I
on
A
K
X
A
N
2105.
2156.
X
5G
N
50
44
M
3
26
33
27
reaches the outlet A', it flows over into the trough A', carrying with it such foreign matters as are soluble
in water, or easily mechanically mixed therewith: the water is allowed to escape from the trough by
the pipe H, leading to a culvert underground. When the water flows off clear, the cock F' is closed
and the throttle-valve J is turned at right angles to the position shown in Fig. 2165, and the shaft D
being caused to revolve in an opposite direction, the sand will be forced downwards and expelled into
the wood-back or cistern K. The valve J being again closed, the operation may be repeated. The
valve J is a disk of wood covered at its periphery with leather, in order to make it water-tight, and
moves on an axis I, and has a handle L, by which it is moved when required. The vessel A is fastened
by a lower flange M, to the transverse timbers N, inserted in the walls of the building, and is further
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881
steadied at the part where it passes through the upper floor G. The cistern K has a slanting bottom
to facilitate the drawing off of that portion of the water which is admitted with the sand at the lower
end. There is a fine grating of pierced zinc P, covered with felt, 80 as to prevent the sand being car-
ried off by the water which flows through the pipe 0 into a drain. The cistern K is supported on tim-
pers R, and others placed crosswise at R'; one side of the cistern has a rectangular opening S, behind
which is placed an agitator T, mounted on an axis T', which extends through the sides of the cistern,
and carries at one end the pulley-wheel U, which is put in motion in the following manner. Beneath
the rafters V, of the upper floor G, is the shaft W, receiving motion from any first mover by a strap
passed over the drum X; this shaft is supported in plummer-blocks Y, bolted to the rafters V, and
carries a pulley Z, from which a catgut or other band passes over the guide-pulley Z', and on to the
pulley-wheel U, and thereby causing the agitator I to revolve in the direction of the arrows and expel
a portion of the wet sand on to the drying-plate: a is a plate of copper, or galvanized iron, having a
raised edge a' on each side to prevent the sand from falling
off; beneath it is the furnace b: a fire is made at c, and the
2167.
products of combustion are allowed to flow under the plate a,
as shown by arrows, and to descend the downward flue d, into
an underground flue, leading to a chimney. On each side of
the plate a there are small bracketed projections e, on which
are bolted the bearings f; in these bearings the cranks g are
caused to revolve by means of the worm-wheels h, which are
0
keyed on the crank g, and are geered into worms ii on the
9
shaft j: this shaft revolves in bearings kk, and has a pulley-
wheel l fixed upon it, which receives motion from another pul-
ley-wheel m. On the shaft to a light iron frame n is supported
16
by the cranks g; this frame has a number of scrapers p fixed
crosswise upon it, 80 that the frame n, which always moves
parallel with the plate a, by the motion of the cranks, is made
to dip its scrapers into the sand at every revolution of the
crank, and to impel it forward on the plate, turning it over,
44
and always advancing it in little heaps, further along the hot
plate. The speed of this part of the apparatus is to be 80 reg-
ulated that the moisture is evaporated by the time it arrives
at q, where it falls from the plate a, on to a sieve r, in a dry
state.
05
The wire sieve r is hung upon a joint at s, and has a small
shaft t below it: this shaft has upon it a tappet-wheel и, which
A
lifts up the sieve a short distance and lets it fall suddenly in
N
M
quick succession, 80 as to shake the sand through it on the in-
clined bottom of the bin v. The shaft of the tappet receives
its motion from the pulley x, on the shaft w, which, by means
of a band, communicates with the pulley-wheel y, keyed on
the shaft t. Such matters as shells, stones, &c, as are mixed
with the sand and are too large to pass through the sieve r,
fall off from it into the trough w, which is raised in the centre
at w', and allows any matters falling into it to roll into the ves-
sels 2, from which they are to be removed, as occasion may
a
require. The sand, by the operations just described, arrives
in the bin v freed from small earthy particles by washing, and
screened from all larger particles than grains of sand, and be-
ing in a dry state is now fit for the grinding operation; and to
facilitate its removal to the mill, and to regulate the quantity
forming one charge, the following contrivance is resorted to.
The sand is first raised by means of the archimedean screw 2
into the receiving-hopper 3. This screw has a central shaft 4,
passing, at its lower end, through the bottom of the bin v, and
resting in a bearing 5, let into a block of stone 6, below the
floor. The upper end of the screw-shaft rests in a plummer-
by
block 7, bolted to one of the rafters V. Near the top of the
screw there is a bevelled wheel 8, which is actuated by
another wheel 9 on the shaft W. The rotary motion thus
transmitted causes the sand to ascend the spiral path of the
screw, in a manner well understood when applied to other
purposes, and finally to discharge itself into the receiving-hop-
per 3, which is secured to one of the rafters V, by an iron
strap 10.
Below the receiving-hopper there is another hopper 11, of larger dimensions, having its bottom in-
clined to one side, where it terminates in a wide spout 11*. This hopper 11 is not fixed like the one
above it, but is supported on scale bearings at 12, projecting from an iron plate 13, bolted to the hop-
per 11. There is one of these pieces on each side of the hopper resting on the forked end of the arms
14*; these arms are keyed on to a shaft 14, which is supported in bearings 15#, formed on the two iron
standards 15; the standards are bolted on to a raised piece of masonry 16, and are steadied at their
upper ends by a stretcher 17, extending across from one to the other. From the centre of the shaft 14
there projects a lever 18, the end of which is screwed and passes through the adjustable weight 19; in
111
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order to prevent the hopper 11 from tilting over, it has an arbor 20, projecting downwards from the
under side of it; at the lower end of the arm, there is a roller 21, which moves up and down between
two guide-bars 22; 23 is a support for the weight 19 to rest upon. The hopper 11 thus supported,
forms a sort of weighing-machine, in which the quantity of'sand required for one charge of the mill is
determined. Its operation is as follows:-The apparatus being in the position represented in the
drawings, the sand is seen flowing from the receiving-hopper 3 through an opening in the bottom of it.
This opening is provided with a plug 24, formed with hollow sides, in the manner usually practised
with the tails or spindles of cone-valves; but as these hollows or flutes do not extend the whole length
of the plug, it is capable of entirely closing the orifice if pulled down. This plug is attached to a small
chain and rod 25. Now 80 soon as the accumulated weight of sand in the hopper 11 is sufficient to
counterbalance the weight 19, it will do so, and will lower itself until the stop 20# reaches the guide-
bars 20, where it will rest. In moving down, the hopper will draw down the plug 24, by means of the
chain 25, and prevent any more sand entering it. During the time the plug-hole is shut, the sand,
which is regularly brought up by the screw, will accumulate in the hopper 3.
In order to regulate the exact weight of sand in the hopper 11, the weight 19 may be screwed fur-
ther off, or nearer to the axis of the lever. 16 is a piece of masonry, raised above the general level of
the floor; on it is placed the horizontal bed-stone 26. This bed-stone is part of an edge-stone mill,
constructed on the general principle of such mills. 27 is a vertical shaft, running in a brass step 28, at
its lower end, and passing up through the floor above, where it is supported by another bearing, and
carries on its upper end a bevel-wheel geering with another bevel-wheel on a shaft, actuated by any
first-mover. These wheels the patentee has not shown in the drawings, but they are well understood.
The brass step 28 is elongated upwards, forming a sort of tubular oil-cup; surrounding the shaft, there
is another tubular piece 29, closed up at top, and attached to the shaft. This tube 29 is inverted over
the oil-cup, and reaches nearly down to the bed-stone, 80 as to prevent any powder working into the
oil-cup. To the outside of the tube 29, there are attached two curved plates or scrapers, shown at 30,
Fig. 2167, for the purpose of removing the materials from the centre of the bed, and distributing them
in the path of the stones 31. On the shaft 27, there are four cast-iron arms, united by a central boss
fitted loosely to the shaft 27, but made to turn with it. In consequence of a projection or feather 32,
two of the arms 33 carry with them the edge-stones 31, mounted with proper bearings, through which
the arms pass. In rolling over any matters in their path, these stones can rise up, carrying with them
the arms and boss on the shaft 27. The other two arms 34 carry at the extremity two small axles 35.
These axles have at their lower ends the scrapers 35#, by which the materials under operation are
brought from the curb or outer iron ring 36, into the path of the "runners."
When one charge of materials has been ground, they are removed to the receiving-box 27. For
this purpose, a portion of the iron curb 36* is mounted on a joint 38. An elongation of the joint-
pin is seen at 39, where it extends through the receiving-box 37, and has a lever and weight 38, for the
purpose of retaining it either up or down. When it is moved down, as at 36*, it allows the ground
materials to be passed into the receiving-box. The better to accomplish this end, the handles 39 have
to be pulled in the opposite direction to that shown in the drawing, 60 as to reverse the scrapers 35#,
as shown by dots in Fig. 2167. The scrapers then cause the materials to pass through the opening in
the curb 36*. When this is accomplished, the jointed piece 36* of the curb is moved upwards, and
retained in that position by the counter-weight 38, the scrapers 35* are restored to their former posi-
tion, and the mill is in readiness for another charge of materials. To do this, the sliding-door 40 of the
hopper 11 is lifted up by the handle, and the charge of sand weighed in the hopper 11 is allowed to
fall into the curb surrounding the bed-stone. The diminution of weight in the hopper 11 will allow it
to ascend into the position shown in the drawing. When it is emptied, the slide 40 is to be shut down,
and the plug 24 lifted up so as to allow the accumulated sand in the receiving-hopper 3 to fall into it.
The refilling of the hopper 11 takes place while the grinding of the former charge is going on. When
the sand is nearly reduced to the required degree of fineness, the soda, potash, or other alkaline matters,
are to be added, and also the chalk, lime, charcoal, or other matters required in glass-making, each in
their proper proportions according to the description of glass intended to be made. The materials are
to be left in the mill until the greater part, if not the whole, of the matters are ground to a fine powder,
when they are discharged into the receiving-box, as before described. He here remarks, that when
alkaline salts are used, their water of crystallization should first be driven off by exposing them to
heat.
The next operation to be performed is, to separate any imperfectly ground portions of the materials,
and to return them back to the mill to be again operated upon. This may be returned and worked
with the next charge each time. Below the box 37 is fixed a plummer-block 41, which receives one
end of the shaft 42, the other end being supported in a plummer-block 43, attached to the case 44 of
the holting or dressing apparatus. The shaft 42 has fixed upon it a number of brushes 45, arranged
so as to touch the wire-gauze drum 46, as they revolve in a similar manner to that already practised in
dressing flour and other matters. Such particles as are fine enough to pass through the wire-gauze fall
into the bin 47; but those particles which are too coarse to pass out at the end of the drum at 48,
are conducted by the spout 49 into the receptacle 50, and may be re-ground as before mentioned. The
shaft 42 receives its motion from a bevel-wheel 51 on the archimedean screw 2, which geers into the
wheel 52 on the shaft 42. The wire-gauze cylinder may be made to vary in fineness, according to the desire
of the manufacturer: but that which the patentee prefers is a range of fineness between five thousand
and ten thousand holes in the superficial inch. The wire-drum is supported by hoops 53 which sur-
round it, and is further protected externally by its case, 44. The shaft 42, at the part where it passes
through the receiving-box 37, is provided with inclined blades, which, as they revolve, assist in bringing
fresh supplies of materials through the opening 37* into the wire-drum. The dressed or finished
materials which fall into the lower part 47* of the bolting or dressing apparatus, are raised to the
upper floor by means of an archimedean screw 54, in the way already described for elevating the sand.
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883
This screw is shown in elevation, its internal structure not differing from those in general use for raising
malt and other materials. In Fig. 2167 it is shown as being cut off on the line A B of Fig. 2165, 80 as
not to obstruct the view of the rest of Fig. 2167. The screw 54 receives motion from a pulley-wheel
55 on the shaft W, the band from which passes over a pulley-wheel 56, on the screw-shaft, the band
being directed in a proper course by the intermediate guide-pulleys 57. The screw, after passing
through the upper floor, (where it is shown broken off,) may either be made to deliver the prepared
materials on to the floor, or by raising them a little higher, deliver them into a large bin or other recep-
tacle, the upper end of the screw being supported in a similar manner to that used to support the
screw 2 at 7. Having ground or crushed the materials above mentioned, the callet or broken glass
is supplied, as heretofore, in the manufacture of like glass. The advantages of this method of preparing
the materials to be used in the manufacture of sheets, plates, or panes of glass, are, first, a saving in
manual labor in the operation of washing, drying, sifting, and weighing; and secondly, the minute
mechanical division of the various matters used will facilitate their chemical action, and therefore save
both time and expense in their formation into glass. Secondly, with regard to the use of an additional
pair of rollers to such machines as are used to roll glass into sheets, for the purpose of either rendering
the cast or rolled plate more smooth and uniform, or for the purpose of impressing or embossing any
designs thereon. Thirdly, with regard to his method of annealing and of heating annealing-kilns or lears,
by the introduction therein of air, heated in pipes or other suitable apparatus, after the manner prac-
tised in heating air for hot blast in the manufacture of iron, which consists in an apparatus for annealing
sheets, plates, or panes of glass. Fourthly, with regard to a method of smoothing or polishing plates,
sheets, or panes of glass, by an endless belt or strap charged with polishing material, which belt is
made to pass in contact rapidly over the surface of the glass, and to traverse slowly across it in a direc-
tion at right angles to the line in which the belt moves over the drums that impel it. The improvements
under this head consist in an apparatus for smoothing or polishing the surface of glass after it has been
ground in the usual manner. For this purpose he constructs the machine or apparatus in such a way
that the polishing-rubber or frictional surface passes rapidly and continually in one direction over the
surface of the glass, and is made also to traverse slowly backward and forward crosswise over the same
surface, the glass being laid on a stationary table of slate or other suitable material.
Process of manufacturing flint-glass and crown-glass for optical purposes.-P. L. Guinand, senior,
of Brennets, in Switzerland, was the first who discovered a special process for this manufacture; and
be has succeeded in manufacturing crown-glass equal in quality to flint-glass that is to say, free from
strise, from bubbles, from threads, and which does not attract moisture.
The invention of M. Guinand, senior, consists in working and stirring the material while in a state of
fusion, by means of a tool made of the same material as the crucible or glass-pot. He made a hollow
cylinder of fire-clay of the same height as the crucible, closed at its lower extremity, open above, with
a flat ledge all round of several centimetres in width. Having heated this cylinder red-hot, he placed
it in the melted glass; then, by meaus of a long bar of iron, bent to a right angle at a distance of some
centimetres from its extremity, which he introduced into the cylinder of fire-clay, he worked and stirred
the glass, by giving the bar a horizontal rotary motion.
For the manufacture of flint-glass, and of crown-glass, he adopted a circular furnace, in the centre of
which is placed the crucible or glass-pot, all the parts of which are exposed to the same temperature;
and covered crucibles are adopted, because with crucibles of this form there is no danger of the glass
being spoiled by particles of the fuel, or by drops, or tears from the crown or arch of the furnace.
The success of the operation depends very much on the form and proportions of the furnace and
crucible.
Figs. 2178 to 2170 represent the furnace, the crucible, the cylinder of fire-clay, the bent iron bar and
its support.
Flint-glass, of the usual density, similar to that used for table-seta, decanters, &c., is composed,
ordinarily, of 300 parts of sand, of 200 parts of deutoxide of lead, and 100 parts of sub-carbonate of
potash.
The density of this flint-glass is from 3.1 to 32.
The following composition, expressed in kilogrammes, gives the quantity necessary to fill the crucible:
sand, 100 kil.; deutoxide of lead, 100 kil; sub-carbonate of potash, 30 kil.
This composition gives a very white flint-glass, of a density of from 3.5 to 3-6, and which is perfectly
suitable for opticians.
It is not necessary to use either lime or arsenic, the only effect of which would be to diminish the
whiteness of the material.
Details of the operation for flint-glass.-The crucible is to be heated in a special furnace kept for
the purpose, and when at a white heat, it is to be introduced, in the usual manner, into the melting-fur-
nace, which has been brought to the same temperature. This operation cools the furnace and the cru-
cible. The furnace must be re-heated in order to bring it to the highest possible temperature before
introducing the materials. This takes about three hours. The throat of the crucible, which has beeu
closed with two stoppers to prevent the entrance of smoke, is then opened, and about 10 kilogrammes
introduced; one hour after, about 20 kilogrammes more; then. two hours after, 40 kilogrammes. Each
time the crucible must be re-closed with the greatest care, and nothing must be put in until the coal on
the grate ceases to give out any smoke. At the end of from eight to ten hours, the whole of the com-
position will have been introduced. The crucible is left without being opened for about four hours
then the stoppers are removed for the purpose of introducing the cvlinder of fire-clay, which has been
heated separately to a white heat in the same furnace, and kept at that temperature until placed in the
crucible: care is to be taken to keep it perfectly clean and free from ashes. At this period, the flint-
glass is melted, but it still contains bubbles. Nevertheless, the bent iron bar is introduced into the
cylinder, and the first stirring is given, which serves to coat the cylinder with glass, and to effect a more
intimate mixture. In about three minutes, the iron bar is white-hot; it is taken out, and the ledge
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884
GLASS.
of the cylinder is placed on the edge of the crucible. This cylinder, being specifically lighter than
the glass, floats slightly inclined, because its upper ledge is outside of the glass. The two stoppers
are 80 replaced as not to push the ledge of the cylinder into the glass, and the stirring up of the fire
is recommenced. Five hours afterwards, a fresh stirring up with a single iron bar takes place, the
glass is already well refined, and then from hour to hour there is a stirring, each time with a single irom
bar ; great care being taken that at each stirring there shall be no smoke in the furnace, and that the
lower doors of the furnace are closed. After having thus used six iron bars, from 25 to 80 centimetres
in thickness of coal is thrown on the grate, which forms a mass quickly reduced to coke, and which
allows the furnace to cool, without exposing the grate uncovered. The various openings of the furnace
are unclosed; the whole furnace and the crucible thus gradually and slowly cool. This operation tends
to cause the bubbles which are not yet disengaged to rise to the surface. At the end of two hours
this operation is finished; the furnace is again brought to the melting beat. After five hours of the
highest temperature, the glass has resumed its greatest fluidity, the bubbles have disappeared, the grates
are completely closed below, and the great (brassage) stirring commences-that is to say, as soon as one
iron bar is hot, another is substituted for it, and on so for about two hours. At the end of this time the
material has acquired a certain consistence, the stirring is not executed without difficulty then the last
iron bar is taken out, the cylinder is removed from the crucible, which is very carefully closed, as well
as the chimneys and openings, except a small hole of two centimetres, to permit the escape of the gas,
which may have remained in the fuel. When the disengagement of gas ceases, the furnace is entirely
closed, and it is suffered to cool, which takes about eight days. The door of the furnace is then removed,
the crucible, with its contents, taken out, usually in a single mass, except some fragments which become
detached round it. The only object now is to make use of this mass and these fragments, the mode
of doing which we will explain directly, after having given the details of the operation for crown-glass,
which, as may be supposed, has a great analogy with the preceding.
Manufacture of crown-glass.-After many experiments, the following composition is found to be the
best white sand, 120 kil.; sub-carbonate of potash, 35 kil.; sub-carbonate of soda, 20 kil; chalk, 15
kil.: arsenic, 1 kil.
The crucible having been placed in the furnace, as for flint-glass, the introduction of all the materials
is to be completed in about eight hours, four or five hours after which the cylinder is to be introduced,
and the first stirring takes place; then, every two hours, a stirring with a single iron bar ; six are to be
executed in this way. The furnace is to cool very slowly for two hours, after which it is to be re-heated
for seven hours, this glass regaining its heat with much more difficulty than flint-glass. The great
1
A
2168.
2169.
o
El
D
3
c
G
B
G
A
B
PH
B
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C
B
2170.
M
E
4
2171.
.
os
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THE
Fig. 2168. Horizontal projection of the furnace and crucible.
Fig. 2170. Section along the line EF, Fig. 2168; that is to say, along
the flue.
Fig. 2169. Vertical section along the line CD of the plan.
Fig. 2171. Vertical section along the line A B of the plan.
stirring then takes place, which lasts about an hour and a quarter. The crucible, the chimneys and the
openings are to be closed, as for flint-glass, and the whole is left to cool. Very commonly, as with flint
glass, a mass and several fragments are obtained.
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885
Parallel faces are made on the sides of the mass, whether of flint-glass or crown-glass, in order to
examine the interior, and to see how it should be divided, for it is never free from strise, which are usually
found collected in one portion of it. After this examination, it is sawed into parallel slices, or trans-
verse sections, in accordance with the observations made. Faces are also polished on the fragments,
for the purpose of examining them, and disks are made of them in accordance with their weight; for
this purpose, they are first heated in a furnace, and then introduced into a muffle, where only the heat
necessary to enable us to mould them is given. If the fragment is irregular, it is partially rounded by
the nippers, and then, with other nippers, it is placed in a mould, under a lever press, which gives
it the exact form of the mould, after which it is taken out with the nippers and carried to the an-
nealing-arch.
The same letters mark the same objects in all the Figs. A, foundation or support of the covered cruci-
ble B. C C, walls of the furnace. DD, openings through which coal is thrown on the grate. E, arch or
crown of the furnace. F, door or opening through which the crucible B is introduced and taken out; there
is a small opening in this. G G, six chimneye. H, an opening. I, hole to facilitate the placing the cru-
cible on its support. K, bent iron bar, for working the fire-clay cylinder. L, support, with a roller
across, on which the bar K is supported. M, hole, with a stopper, through which the coal is thrown.
N, hole, with a stopper, through which the grate is cleared. 0, hood of sheet-iron, under which the
chimneys terminate. a a, grate of the furnace. b, throat of the crucible. c, level of the melted glass.
d, fire-clay cylinder for stirring. e, opening. ff, bars supporting the grate. g, door of the opening e.
GLUE, is prepared from the clippings of hides, hoofs, &c. These are first washed in lime-water, and
afterwards boiled and skimmed; the solution is then strained through baskets, and gently evaporated
to a due consistency; then cooled in wooden moulds, cut into slices and dried upon nets. Good glue is
semi-transparent, deep brown, and free from spots and clouds. When used it should be broken in
pieces, and steeped for twenty-four hours in cold water, by which it softens and swells; the soaked
pieces are then melted over a gentle fire, or, what is better, in a water bath, and in that state applied
to the wood by a stiff brush. Glue will not harden in a freezing temperature, the stiffening depending
upon the evaporation of its superfluous water. The chemical properties of glue are those of an impure
gelatine.
The only machinery used in the manufacture are the three coppers, upon different levels, in which
the skins, &c., are boiled. The uppermost copper, being acted upon by the waste heat of the chimney,
provides warm water in the most economical way; the second contains the crude materials, with water
for dissolving them; and the third receives the solution to be settled. The last vessel is double, with
water contained between the outer and inner one, and discharges its contents by a stop-cock. The last-
made solution has about one five-hundredth part of alum, in powder, usually added to it, with proper
agitation, after which it is left to settle for several hours.
GLYPHOGRAPHY, recently invented, is an electrotype process, enabling the artist to become the
engraver of his own work. The manipulation is thus minutely described by the inventor, Palmer:
A piece of ordinary copper-plate, such as is used for engraving, is stained black on one side, over
which is spread a very thin layer of a white opaque composition, resembling white wax both in its
nature and appearance: this done, the plate is ready for use.
In order to draw properly on these plates, various sorts of points are used, which remove, wherever
they are passed, a portion of the white composition, whereby the blackened surface of the plate is ex-
posed, forming a striking contrast with the surrounding white ground, so that the artist sees his effect
at ouce.
The drawing, being thus completed, is put into the hands of one who inspects it very carefully and
minutely, to see that no part of the work has been damaged or filled in with dirt or dust; from thence
it passes into a third person's hands, by whom it is brought in contact with a substance Laving a chem-
ical attraction or affinity for the remaining portions of the composition thereon, whereby they are
heightened ad libitum. Thus, by a careful manipulation, the lights of the drawing become thickened
all over the plate equally, and the main difficulty is at once overcome; a little more, however, remains
to be done. The depth of these non-printing parts of the block must be in some degree proportionate
to their width; consequently, the larger breadths of lights require to be thickened on the plate to a
much greater extent, in order to produce this depth. This part of the process is purely mechanical, and
easily accomplished.
It is indispensably necessary that the printing surfaces of a block prepared for the press should
project in such relief from the block itself as shall prevent the probability of the inking-roller touching
the interstices of the same whilst passing over them. This is accomplished in wood engraving by
cutting out these intervening parts, which form the lights of the print, to a sufficient depth; but in
glyphography the depth of these parts is formed by the remaining portions of the white composition on
the plate, analogous to the thickness or height of which must be the depth on the block, seeing that the
latter is in fact (to simplify the matter) a cast, or reverse, of the former. But if this composition were
spread on the plate as thickly as required for this purpose, it would be impossible for the artist to put
either close, fine, or free work thereon; consequently the thinnest possible coating is put on the plate
previously to the drawing being made, and the required thickness obtained ultimately as described.
The plate thus prepared is again carefully inspected through a powerful lens, and closely scrutinized,
to see that it is ready for the next stage of the process, which is, to place it in a trough, and submit it
to the action of a galvanic battery, by means of which copper is deposited into the indentations thereof,
and, continuing to fill them up, it gradually spreads itself all over the surface of the composition, until
a sufficiently thick plate of copper is obtained, which, on being separated, will be found to be a perfect
cast of the drawing which formed the clichée.
Lastly, the metallic plate thus produced is soldered to another piece of metal to strengthen it, and
then mounted on A piece of wood to bring it to the height of the printer's type. This completes the
process and the phographic block is now ready for the presa.
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GOLD.
It should, however, have been stated previously, that if any parts of the block require to be lowered,
st is done with the greatest facility in the process of mounting.
One manifest advantage which glyphography has over etching and wood engraving is, that the artist
makes his drawing as he intends it to appear. No reversing is necessary the work during the progress
of drawing is as immediately conspicuous as if it were done upon paper with a black-lead pencil. Com-
pared with wood engraving, with which it comes into direct competition, it seems susceptible of more
delicacy, and is not more expensive than wood engraving of approximate quality.
GOLD. (Syn. Anglo-Sax, gold: Dutch, goud: Germ., gold: Goth., gulths: Icel, gull: Dan. and
Swed., guld: Tart., goltz Pol., zloto Gr., chrysos: Lat,, aurum: Ital., Span., Port., oro: Fr., or
Welch, aur: Pers., zuraljin Hind., sonnau: Arab., dahaba: Heb, Chald., Sum, zahav.) In its native
state, this metal has never been found pure, but always alloyed with silver; and it frequently contains
copper in addition. The proportion of silver is, from less than one per cent. up to an amount that ren-
ders it, more properly, an ore of silver. Copper, when present, is usually in very small quantity.
Pure gold is unalterable by atmospheric agents, and consequently, preserves its beauty and lustre
indefinitely.
This fact, taken in connection with the facility of working the native metal, must have attracted the
notice of man at a very early period. As a consequence, we find it spoken of in the most remote rec-
ords of history.
Physical properties.-Pure gold has considerable lustre; less, however, than steel, silver, mercury,
or platinum, but more than copper, tin, and lead. In masses, it has a bright yellow color, very slightly
tinged with red; but when beaten into leaves exceedingly thin, it becomes translucent, and assumes R
greenish tint. It was suggested by Vauquelin that its true color is blue, and that the appearance of
green is due to a mixture of yellow rays, reflected from the thin leaf of gold. Buisson cites many ex-
periments to prove that when reduced to an impalpable powder, by electricity or otherwise, the color
of gold is purple. It seems, therefore, that savans have not yet been able to agree as to what is the
true color of this long-known substance.
Pure gold is softer than silver, and possesses malleability and ductility in a greater degree than any
other. metal. It may be beaten into leaves so thin as to require 251,154 folds to make one inch in
thickness. The coating of gold upon ordinary gold lace is yet thinner; because in making it, a small
cylinder of silver is covered with 1-48th its weight of gold, and drawn into wire, which is rolled until
11.8 feet in length weigh but one grain. Reaumur covered a cylinder of silver with 1-360 its weight
of gold. It was drawn into a wire of which 6 feet weighed one grain; and then rolled to a width of
1-48th of an inch, which increased its length to 7.5 feet; and yet the silver was so completely covered
that the microscope failed to detect the least appearance of it.
The tenacity of gold is less than that of platinum, copper, and iron. A weight of 1733 lbs. is suffi-
cient to break a wire whose diameter is 0-0784 inch, or nearly 1-13th of an inch. Its tenacity is les-
sened by hammering; but its stiffness and elasticity are increased. The tenacity may be restored by
exposing the metal to sufficient heat. A temperature barely enough for fusion renders it brittle; it
must be more strongly heated to recover its ductility entirely. It also becomes brittle when suddenly
cooled.
It expands upon being heated more than silver and copper, and less than iron and mercury. Whilst
passing from the liquid to the solid state, it contracts more than any other metal. A volume which is
1. at a temperature of 32° F., becomes 100146 at 212° F.
According to Berthier, the specific gravity of gold after melting, is 19-258, which is increased to
19367, if the metal has been much hammered. Berzelius gives 19:40 to 19-65, and other experi-
menters obtained results between these extremes. We are disposed to adopt 193 for melted gold,
and from that to 19:65 for hammered gold, according to the amount of compression.
Its atomic weight is 1243'013, oxygen being unity, and 1992 in a system where hydrogen is taken
as unity.
It conducts heat more rapidly than any other metal, and is a better conductor of electricity than any
other, except copper.
Chemical properties and compounds.-The chemical symbol of this metal is Au.
When it is heated to about 2016° F., it enters into fusion; and when completely liquid, assumes a
bluish green color. It cannot be volatilized at the temperature of our hottest furnaces but when ex-
posed to the compound blowpipe, it is converted into vapor, which will gild a silver plate held above
it. It may be also volatilized by the sun's rays, in the focus of a very powerful burning lens. In very
fine powder, it becomes incandescent, at the temperature of 122° F.
Gold does not oxidate at ordinary temperatures, nor in the hottest furnaces; but a slight oxidation
takes place when exposed in thin leaves to the lens, burning mirror, compound blowpipe, or a galvanic
battery of ample heating power. In a vacuum, the electric spark divides it into a very minute
powder.
Few of the acids act on gold singly. Nitric acid, when concentrated and boiling, exerts a feeble
though sensible action. Nitrous acid also attacks it. Sulphuric acid, even if highly concentrated and
boiling, produces no effect whatever. Selenic acid dissolves gold, and is converted into selenious acid.
It was observed by Proust, that when in an extremely minute state of division, gold was dissolved in
very small proportion, by concentrated and boiling nitric acid. Mixtures of nitric acid with hydrochloric,
hydrobromic, hydriodic, and some other acids, dissolve it readily, and form chlorides, bromides, and
iodides of gold. It may also be dissolved, and a chloride formed, by treating it with a mixture of 4
parts nitric acid and 1 part sal ammoniac, or any other alkaline hydrochlorate. The same result may
be attained by using hydrochloric acid, mixed with any nitrate whatever.
Alkaline solutions have no action upon gold; but in the dry way, and at a high temperature, (though
insufficient for fusion,) it has been shown by Buchner that divers oxygenated substances give out their
oxygen to gold, or determine its absorption from the atmospheric air.
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GOLD.
887-
Tenant has proved that when nitrate of potash is heated with finely divided gold, the latter is sensi-
bly attacked and a combination of oxide of gold and potash is formed-a circumstance that should be
borne in mind by artists who purify their gold filings by this means. The gold which combines with
the alkali, may be recovered again by treating the alkaline mass with water; when the whole of the
gold will be precipitated in a fine powder.
With borax, at a red heat, the color of the surface of gold is rendered lighter, but the ordinary color
is restored again by heating it to redness, with either nitrate of potash or common salt. This was
known to the ancients. Exposed to heat whilst covered with charcoal in powder, the surface assumes
a beautiful shade of yellow; but whether by the formation of a carburet, has not yet been determined.
Sulphur and selenium do not act on gold at any temperature, nor does the vapor of hydrosulphuric
acid; but the alkaline persulphurets readily form sulphurets with gold, both in the humid and dry way.
Phosphorus and arsenic, aided by heat, combine directly with it. Gaseous and liquid chlorine also act
upon it, and the latter dissolves it readily. Iodine has no perceptible effect, further than to tarnish the
surface. Hydriodic acid dissolves it.
Oxides.-The affinity of gold for oxygen is less than that of any metal. They combine in two pro-
portions, constituting the protoxide and peroxide of gold; and there is some reason to believe, with
Berzelius, in the existence of an intermediate oxide of a purple color, containing twice the amount of
oxygen of the protoxide.
Protoxide of gold is obtained by mixing a cold solution of caustic potash with protochloride of gold.
It has a deep green color, and soon decomposes spontaneously into metallic gold and its peroxide;
which also occurs upon the application of acids, with which the protoxide never forms salts.
It consists of gold
96.13
Oxygen
3.87
Peroxide of gold may be formed in several ways; but the best mode, according to Pelletier, is to
heat magnesia or oxide of zinc in slight excess, with a solution of perchloride of gold, and wash the
residuary matter with nitric acid. If concentrated acid be used, we have the anhydrous peroxide; but
with diluted acid, the hydrated peroxide is produced. This peroxide has a styptic, metallic taste, re-
tains its oxygen very feebly, and forms salts only with concentrated nitric, sulphuric, and acetic acids.
The addition of water to these solutions precipitates the gold, either as an oxide or in the metallic
state. Peroxide of gold combines with vitreous substances in fusion, and communicates the beautiful
yellow color 80 much admired in artificial gems and stained or colored glasses.
Although the term peroxide of gold is usually applied, we might perhaps more properly rank it
with the acids, and designate it by the term auric acid. It does not form stable compounds with other
acids, but, like them, combines with metallic oxides, forming a class of salts called aurates. The solu-
tions of these are usually colorless, or nearly so; but may be tinged yellow by the addition of other
acids. The oxygenated acids produce precipitates of hydrate or peroxide of gold, having a violet color
more or less deep, or even black, according to the strength of the solutions.
The aurates of soda, potash, and baryta, are very soluble in water: the solutions are colorless, and
have an alkaline reaction.
The aurate of magnesia is slightly soluble in water, but more so if chloride of magnesium be present.
When solid it is easily decomposed by nitric acid, which produces very pure peroxide of gold, or its
hydrate, according to the strength of the acid.
The purple powder of cassius, so much used to produce a fine purple color in artificial gems, enamels,
and glass, is sometimes classed with the aurates, although it probably does not contain auric acid.
Chemists are not agreed in regard to the precise nature of this valuable compound of gold, but our
limits do not permit the discussion of the question here.
There are several different processes by which it can be prepared; and it varies in its tints accord-
ing to the method adopted.
Buisson gives the following as the best to produce a beautiful purple color :-(a) Dissolve 1 part
granulated tin in hydrochloric acid, avoiding an excess of the latter. (b) Dissolve 2 parts tin in a mix-
ture of 3 parts nitric and 1 part hydrochloric acid; taking care, ns before, that the solution be exactly
neutral. (c) Make a neutral solution of 7 parts gold in a mixture of 1 part nitric and 6 parts hydro-
chloric acid. Dilute the last solution with a large quantity of water, and mix it with the deutochloride
of tin (b), and then add the solution of protochloride (a), drop by drop, until the precipitate shall
assume the desired purple color. An excess of the protochloride (a) changes the color of the powder to
brown, and an excess of the deutochloride (b) gives it a violet tint. As soon as the desired color is
attained, the liquid should be decanted, and the precipitate washed to prevent further change in its
color. It retains water when heated to 212° F.
Its composition, according to Buisson, is,
Gold
28.5
Deutoxide of tin
65.9
Chlorine
5.2
The chlorine in this specimen might all have been removed if it had been sufficiently washed.
Berzelius analyzed a specimen of a fine purple; which contained,
Gold
28.35
Deutoxide of tin
64.00
Water
7.65
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GOLD.
Oberkampt found two specimens to consist of,
Clear purple.
Violet color.
Gold
795
398
Oxide of tin
20.5
60.2
These results show wide differences in composition.
It gives a beautiful purple color to glass, which sometimes disappears by fusion, but reappears in a
smoky flame. Besides this, several other colors are produced in glass by mixtures with the purple
powder. With oxide of silver we have a deep crimson, and with oxide of antimony a deep brown.
Other compounds, giving a purple color to fused glass, may be formed by mixing solutions of chloride
of gold with protonitrate of tin, chloride of antimony, or of bismuth, or even protosulphate of iron.
Sulphurets of gold-There are two sulphurets, both of which are reduced to the metallic state, at a
low red-heat.
The protosulphuret is dark brown. or nearly black; and is obtained by passing sulphuretted hydro-
gen gas through a hot solution of chloride of gold. It consists of
Gold
92.51
Sulphur
749
The deutosulphuret has at first a dark yellow color, which becomes brown when dried. It is pre-
pared by passing sulphuretted hydrogen gas into a cold solution of chloride of gold, and consists of,
Gold
8047
Sulphur
1953
Phosphuret of gold is prepared by passing an excess of phosphuretted hydrogen gas into a solution
of gold. At first the metal is precipitated, which at length combines with the phosphorus. The com-
pound is black, without metallic lustre. It is more fusible than metallic gold itself; and, after being
melted, becomes of a grayish white color, crystalline and brittle with a granular fracture.
Fulminating gold-There are two different kinds of this compound, both of which were supposed to
be aurates of ammonia; but Dumas has shown that nitrogen also exists in them.
The first has a dark gray color, and is prepared by digesting a solution of chloride of gold with am-
monia, and carefully drying the precipitate 80 as to lessen the danger of explosion. At a little above
212° F. it explodes with great violence from a slight blow, or from friction. It consists of
Gold
7760
Nitrogen
5.56
Ammonia
6.65
Water
11.25
The second species is of a deep yellow color, and is made by digesting the chloride of gold in a
alight excess of ammonia, and drying as before. At the temperature of 212° F, when suddenly heated,
it detonates most violently; but after having been very slowly heated to 266°, the temperature may
be raised to 300°, and even 320°, before it will explode.
Great caution is requisite on the part of those who prepare or handle these and other fulminating
compounds, and the many terrible accidents which have occurred, should warn all but experienced
manipulators from meddling with them in any manner.
Chlorides.Gold combines in two proportions with chlorine.
Protochloride of gold is prepared by cautiously evaporating a solution of the perchloride to dryness
on a sand bath, and heating the residue at the temperature of melting tin (frequently stirring with a
glass rod) until it ceases to give off chlorine. It forms a white saline mass, slightly tinged with yellow.
It is insoluble in, nor does it color cold water, if free from perchloride. It is little subject to decompo-
sition at ordinary temperatures, if secluded from the light and kept dry; but both light and heat de-
compose it into perchloride and metallic gold; and boiling water very promptly does the same.
It consists of Gold
91.51
Chlorine
8-49
Perchloride of gold may be obtained by dissolving pure gold in thin leaves or fine powder, in a mix-
ture of 1 part (by measure) pure nitric acid with 4 parts pure hydrochloric acid, and cautiously evap-
orating the excess of acid. It is soluble in water, and the solution is yellow; but becomes pale if there
be an excess of acid. It is decomposed by degrees, if exposed to light; and, at a red-heat, the chlorine
is driven off, leaving the gold. It consists of
Gold
6518
Chlorine
3482
Metallic gold is precipitated from its solution by phosphorus, and most of the metals and the salts of
iron. The salts of tin in solution produce purple precipitate. If gold be precipitated by means of a
solution of caustic potash in alcohol, we obtain it in an extremely minute state of division, suited for
painting, for gold inks, and other purposes.
The solution of this perchloride in ether is used for gilding the surfaces of iron and steel; the dura-
bility of which is increased by previously immersing the article for one or two minutes in a solution of
silver or copper, so as to cover it with a thin pellicle of either of these metals. The gilded surface
must then be well burnished.
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Perchloride of gold unites with most of the metals to form compounds called double chlorides, which
our limits will not permit us to notice.
Bromide of gold, when dried, has a blackish color, without metallic lustre. It dissolves readily in
water, and gives to it a deep red color; which is also that of the crystals produced from the solution.
It consists of Gold
468
Bromine
532
Iodide of gold is insoluble in cold water, and slightly soluble at 212° F. It has a greenish yellow
color, and consists of
Gold
34.5
Iodine
65.5
Alloys of gold-When 12 parts manganese and 88 parts gold are melted together, an alloy is pro-
duced, having a pale yellowish gray color, with considerable lustre and hardness, and little ductility.
Its fracture is granular and spongy. It is less easily fusible than gold, and the manganese may be
completely separated by roasting.
Iron and gold have a strong affinity for each other, and the latter may be united in all proportions
with steel or cast-iron. Gold may be used for soldering iron. An alloy with 8 per cent. of iron is of a
pale yellowish gray color, very ductile and tenacious, and harder than gold. With from 15 to 20 per
cent. of iron, the alloy is gray, and will take a very beautiful polish. It is used in jewelry under the
name of gray gold. When 75 to 80 per cent. of iron is alloyed with gold, it has the color of silver, and
is so hard as to be applicable to the purposes of cutting instruments.
Cobalt readily unites with gold, and forms alloys of a dull yellow color, which are brittle when the
proportion of cobalt is 1-60th.
Nickel and gold have a brass yellow color, and are also brittle.
Copper has a great affinity for gold, and combines in all proportions. It heightens the color of gold,
and increases its hardness, whilst its ductility is somewhat impaired. The maximum hardness is at-
tained with 1-18th copper. These alloys being more fusible than gold, are used for soldering this metal.
The alloy called jewellers' gold should contain at least 746 of gold. In France, according to Ber-
thier, it varies from 92 to 25 per cent. In Great Britain, 18 carats or 75 per cent. is the standard for
jewellers' gold: although the proportion of this metal is rarely 80 much. In Sweden, it is 76.6 per
cent., it being there, as in most parts of Europe, regulated by law. In the United States, the standard
of gold is not subjected to any legal provision, except in regard to coin, which must contain 9 parts gold
to 1 alloy of which alloy, at least one half must be silver. In Great Britain, the coin consists of 11
parts gold and 1 copper; and in France, 10 parts of gold and 1 part of copper.
In order to deepen the color of gold alloyed with silver, artists have a mode of alloying a small por-
tion of copper with the surface only, which is done in the following manner: 1 OZ. of yellow wax is
melted, and there is added to it a mixture of 2 OZ. calcined alum, 12 OZ. red chalk, 2 OZ. verdigris, and
2 OZ. peroxide of copper, (copper scales.) The four last named must be ground to an impalpable pow-
der, completely mixed with the melted wax, and moulded into sticks for use. After the surface of the
gold is well rubbed over with these sticks, the article must be exposed to heat sufficient to burn off the
wax entirely. It is then burnished, and washed with a liquor composed of one pint of water to 2 OZ.
ashes produced by calcining argal or crude tartar, 2 OZ. common salt, and 4 OZ. sulphur.
Antimony unites easily with gold, and produces alloys of a color more or less pale, according to the
proportions used. They are brittle, and have a dull granular fracture. The presence of a very minute
proportion of antimony destroys the ductility of gold. It was from this faculty to render brittle, which
antimony exerts over all the other metals, that the earlier chemists gave it the title of regulus, or little
king. To its sulphuret was given the name of lupus metallorum, because, in the purification of gold,
its feeble affinity allowed it to yield the sulphur to the inferior metals, while itself combined with the
gold. The sulphuret is still used for the same purpose.
Tin forms with gold compounds more fusible than the latter; they are ductile when cold, but crum-
ble at a red heat, if the proportion of tin be as much as 1-37th. With 1-12th tin the alloy is of a pale
yellow color, but slightly ductile, and has an earthy fracture.
Zinc, in small proportion, renders gold brittle; even its vapors sensibly produce this effect on gold in
fusion. With 1.10th zinc the alloy is very brittle. and has the color of brass. With t zinc it is white,
very hard, and takes a high polish. Hellat asserts that an alloy of seven parts zinc and one part of
gold is entirely volatilized in a furnace.
Bismuth forms with gold brittle alloys of a brassy color. The vapor of bismuth is also sufficient to
diminish the ductility of gold.
Lead forms alloys with gold which are brittle in every proportion. It requires but one part of lead
in 500,000 of gold to alter sensibly its ductility. An alloy consisting of one part lead and twelve parts
gold is extremely brittle, and has a dull granular fracture similar to that of porcelain.
Silver and gold may be united by rapid fusion in all proportions; but if the fused mass be very
slowly cooled, part of the silver, in combination with a small proportion of gold, separates and floats
upon the surface, leaving beneath an alloy of five parts gold and one part silver. The alloys of these
metals are more fusible than gold, and have 9 greenish tinge even 5 per cent. of silver produces a
decided change of color. The proportions used for the green gold of the jewellers are 708 of gold, and
29.2 of silver. These alloys are very ductile, and are harder, more elastic, and more sonorous than
either of the metals themselves. The maximum bardness is attained when the proportion of silver
is one-third.
Platinum may be united with gold in all proportions; but to produce an alloy completely homo-
geneous, it should be exposed to a very high temperature, 80 as to effect a perfect fusion. These alloys
112
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GOLD.
are ductile and elastic. When they contain from 7 to 10 per cent. of platinum the color is dull yellow,
like tarnished silver. With 1-5th it exactly resembles platinum; with 1-17th platinum it is in appear-
ance not distinguishable from gold.
Platinum and silver together combine with gold in all proportions, forming double alloys which are
ductile, and possess more stiffness and elasticity than alloys of gold and silver only. Platinum is
sometimes introduced into an alloy of silver, gold, and copper, called doré, and it is not easy to detect
the fraud.
Palladium and gold form alloys with less ductility than that of the pure metals. They have a gran-
ular structure, and vary in color from white to gray. With equal parts it is nearly white, and a very
small proportion lessens the color of gold.
Rhodium and gold form alloys, according to Del Rio, which are brittle, unless the proportion of the
former be very small, when it hardens the gold without impairing its ductility. With 1-7th rhodium
the color is unaltered-a striking difference between its effects and those of platinum and palladium
upon gold.
Iridium, in being alloyed with gold, but slightly affects its color, and produces ductile alloys.
Osmium also forms ductile alloys with gold.
Arseniurets of gold (as alloys of arsenic with gold are termed) may be formed by exposing heated
gold to the vapor of arsenic. The gold absorbs a very small proportion, but retains it with so strong
an affinity that it cannot be entirely separated even at a very high temperature. This alloy is brittle.
Tellurium may be combined with gold artificially, by treating the latter in solution with telluretted
hydrogen gas. The native combinations of these metals found in Transylvania will be noticed among
the ores of gold.
Mercury and gold form alloys called amalgams. They may be formed by immersing or agitating
gold in mercury, which dissolves it even at common temperatures; but the combination is hastened by
heat. An alloy saturated with gold and compressed in chamois skin is white, and at first soft, but soon
becomes solid. It crystallizes in four-sided prisms, and contains two parts of gold and one of mercury.
When sufficiently soft to be kneaded between the fingers, it contains SIX or seven parts mercury and one
of gold. Amalgams are used in gilding, (q. v.)
Mineralogical Occurrence of Gold.
1. Native metallic gold.
2. Gold containing rhodium.
3. Gold with silver and tellurium.
4. Gold with silver, tellurium, and lead.
5. The same as the last, with the addition of antimony.
6. Gold in iron and copper pyrites and Galena, usually in very small proportion.
1. Native metallic gold.-It is in this state that nearly all the gold obtained by man is found; but, as
has been already stated, never entirely apart from other metals. It varies in color from gold yellow to
brass yellow, grayish and greenish yellow, depending upon the nature and proportion of the metals
with which it is alloyed.
It occurs in grains, scales, threads, and plates, and also in masses from a few grains in weight to
several ounces; and in a few rare instances lumps have been found weighing many pounds. It also
occurs in small crystals having the form of the cube, or its derivatives.
Its specific gravity varies according to the proportion of other metals with which it is alloyed, and is
much less than would be calculated from that of the pure metals.
Boussingault and others have endeavored to show that the silver contained in native gold is united in
definite proportions. We think, however, this view is altogether untenable, in the face of the fact that
the numerous analyses which have been made show that the silver in native gold exists in all propor-
tions, from less than one per cent. and upwards, until it constitutes more than half the weight of the
native alloy.
The following table gives the composition of specimens from the principal gold regions now worked
in various parts of the world.
SPECIFIC
LOCALITY.
GOLD.
SILVER.
ANALYST.
GRAVITY.
1 Schabrowski, Siberia
(copper 35)
98.96
0.16
Rose.
2 Saxony
9690
2:00
Lampadius.
8 Upper California
9570
not stated.
U.S. Mint.
4 Scharlausch, Siberia
*
95.00
480
Rose.
5 Boruschka,
"
*
94.40
480
17060
"
6 Brazil
(0:15 platinum)
9400
5.85
D'Arcet.
7 Bellembugeush, Siberia
93.50
6:40
Rose.
8 Peros Pawlosk,
"
92.60
7.10
"
9 Upper California
92.10
not stated.
U.S. Mint.
10 Kuslinski, Siberia
9190
800
Rose.
11
Ufaley,
"
9140
8.50
"
12
Upper California
92:10
not stated.
U. S. Mint.
13
"
"
loss in melting 0.38
9070
880
Rivot, Paris.
14
"
"
9050
880
U.S. Mint.
15 Kurchwa, Siberia
9030
960
Rose.
16 Czarwo Nuolajewesk, Siberia
8940
10:00
17480
a
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SPECIFIC
LOCALITY.
GOLD.
SILVER.
ANALYST.
GRAVITY.
17
Besolk, Siberia
8870
11:30
Rose.
18
Malposo, New Grenada
88.58
11.42
Boussingault.
19
Upper California
8850
not stated.
U.S. Mint.
20
Llano, New Grenada
88.24
1176
14706
Boussingault.
21
Baja,
"
8815
11.85
"
22
Rio Sucio,
"
87.94
12-06
14690
"
23
Upper California
8750
not stated.
U.S. Mint.
24
Gasuschka, Siberia
87.30
12:30
Rose.
25
Petro Powlowsk
86.50
18:20
16870
"
26
Burburu, Transylvania
8510
1470
Boussingault.
27
Ojas, New Grenada
8450
15.50
"
28
Boruschka, Siberia
88.90
16.10
17060
Rose.
29
Trinidad, New Grenada
8240
1760
Boussingault.
30
Upper California
81.20
not stated.
U. S. Mint.
31
African gold dust
(11.80 copper)
78.00
948
Thomson.
34
Titisibi, New Grenada
74.00
26.00
Boussingault.
35
Guano,
"
73.68
2632
"
Marmato,
"
in cubic and octahedral
36
73.45
26.55
12666
"
crystals in a vein of pyrites in syenite
37
Otromma, N. Grenada, in octahedral crystals
73.40
26.60
"
38
Santa Rosa,
"
6493
3507
14149
"
39
Transylvania, in cubic crystals
64.52
35.48
"
40
Schlangenberg, Siberia
5400
36.00
Klaproth.
41
"
"
28.00
72.00
Fortia.
Those marked (*) contained traces of copper. No. 41, containing 72 per cent. of silver, would be classed more properly
with native silver.
So far as is yet known the gold from California is alloyed with silver only; the oxide of iron, separ-
ated in melting, exists in the minute cavities and fissures in the scales, and adheres to the surface only.
The average loss in melting is stated to be about 21 per cent., which, as the assays were made from
the melted metal, would somewhat reduce the per centage of gold.
Although obtained over a large extent of country, the California gold from the western slope of the
Sierra Nevada has more uniformity in its composition than that of other gold regions, from which a
sufficient number of specimens have been analyzed to enable us to form an opinion. This will appear
from the following table giving the maximum and minimum proportions, which have been found to
exist in some of the most important localities.
Maximum.
Minimum.
California
9570
81:20
Siberia
98.96
28.00
South America, (New Grenada, &c.)
8858
6493
One specimen from Siberia contained nearly 99 per cent. of gold, and 3 per cent. of silver and copper,
Deing the purest native gold yet known.
The gold of the western slope of the Andes contains more alloy than that of Siberia or California.
Of the other regions the analyses reported hitherto consist generally of a single specimen, or of 80 few
that no deduction can be made from them.
An opinion seems to have prevailed in California, that the gold from the affluents of Feather river
was purer than that from the districts further south, but the assays at the United States Mint do not
confirm this opinion; on the contrary, they show that the average rate of purity seems about equal
throughout the region. The usual range after melting is from 87.5 to 90.5 per cent. of pure gold. The
general average is between 88.5 and 89. per cent. If, therefore, the value of the silver be added, it
would appear that the average value of the gold from California differs little from the standard for the
gold coin of the United States.
3, 4, and 5. Telluric ores of gold-In the metalliferous districts of Transylvania a considerable
amount of gold is obtained from ores consisting of combinations of tellurium with several other metals.
The following indicates the composition of the most important of these:
Sp. gravity.
Gold.
Silver.
Copper.
Antimony.
Lead.
Sulphur.
Tellurium.
Observer.
1
5-723
30-00
10:00
60
Klaproth.
2
10678
2675
8.50
1950
0.50
4475
"
3
8-918
900
0.50
1:30
5400
3.
32.20
"
4
750
1.
46'00
2.50
26:40
Brandes.
5
6840
670
180
4'50
6310
1170
13.
Berthier.
The first variety crystallizes in small rhomboidal prisms. It is soft, with an irregular fracture, and
of the color of steel.
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GOLD.
The second is white, tinged with yellow. In some cases it is in lamellæ, but appears granular in
others, and crystallizes in four-sided rectangular prisms and in small lamellæ.
The third has a deep leaden-gray color, approaching that of specular oxide of iron, with a very
shining lustre. It is soft, slightly flexible, has a lamellated structure, and crystallizes in hexagonal
plates slightly elongated.
The fourth closely resembles in appearance the third, from which it differs little in composition.
Although the fifth differed little in external appearance from the two last, it will be observed that in
the relative proportions of its constituents there is a considerable variation.
6. Gold in iron and copper pyrites, and in galena.-The native sulphuret of iron 80 generally con-
tains traces of gold as to occasion the remark by Gahn, that it was rare to meet with a specimen of this
mineral from which gold was entirely absent. The same may also be said, in a great measure, of the
native sulphurets of copper and iron, or copper pyrites, and the sulphuret of lead, or galena, although
it is probable that it does not 80 uniformly apply to the two latter, and especially the last.
Geological distribution of gold, and its localities.With the exception of iron, (and possibly copper,)
it may safely be asserted that the geological districts within which gold occurs embrace a larger aggre-
gate area than those of any other metal. And yet the proportion of gold to that of the substances from
which it must be separated for the use of mankind is 80 extremely minute, that the cost of eliminating
it must necessarily be such as to maintain a very high commercial value for this metal in all future
times.
Native gold occurs in veins which intersect hypogene or igneous, as well as metamorphic rocks; but
the veins in the former have hitherto almost always proved too poor in metal to be worked with profit,
unless in connection with other metals.
Among the metamorphic rocks, especially in talcose alates, we find the auriferous veins most numerous
as well as most productive. And although the veins in porphyries, trap, and other hypogene rocks,
usually are much less rich in metal than the slates, yet the veins in these are little productive, or do
not contain gold at all, where these rocks occupy extensive areas without intrusive rocks forced up be-
tween or around them.
These conclusions are sustained by the fact of this being the geological structure of all the districts
in the world known to contain gold, under circumstances that permit it to be extensively availed of for
the uses of mankind.
The gold-bearing veins usually consist of quartz. of a texture so firm and hard as to require a large
expenditure in mining it, compared with the value of the metal obtained; more especially when it is
worked to considerable depths below the surface, where atmospheric agents have not impaired the
solidity and firmness of the vein-stone.
These, like all true veins, are generally inclined at a considerable angle from the plane of the horizon,
and are often vertical, or nearly so. In thickness they vary considerably: the same vein is sometimes
contracted to a width of an inch or less, whilst at other points it is expanded in thickness to many yards.
They extend downwards to greater depths than the miner has ever reached.
The gold occurs sometimes disseminated throughout portions of the vein in minute scales, often 80
small as to be invisible to the naked eye; then again it is found in scales, plates, or amorphous masses,
varying in size from the smallest visible dimensions to those having considerable weight. These are
sometimes irregularly distributed throughout the vein-stone, but most commonly extend within parts of
the vein, or upon its sides. Small crystals of gold also occur in the cavities of the vein-stone. Iron
pyrites usually accompanies native gold, and sometimes also copper pyrites, both containing some gold
disseminated within them, and not chemically combined.
By far the larger proportion of gold hitherto has been procured from the deposits of diluvium and
alluvium, in the valleys and ravines which have been formed in those regions where metallic veins
existed prior to the formation of such valleys and ravines.
The gold in these transported deposits (or drift, as they may be termed) formerly existed in those
portions of the veins destroyed by the operations of nature producing these denudations, and which often
result in the formation of glens, ravines, and narrow valleys. This destruction and re-formation are
incessantly going on; but during the present geological period with less energy than in that earlier era
called the drift period by geologists. Now, as then, carbonic acid and oxygen, aided by heat and water,
are the chief agents by which the rocks and stony matters are disintegrated. The currents of water in
hilly and mountainous districts have usually considerable rates of descent, 80 as readily to float off the
more finely-divided portions in sand and mud, as well as to remove the larger gravel and boulders.
The only substances possessing specific gravities too great to be moved far from whence they were
liberated, are the heavier metals and some of their oxides. The weight of gold is such that it is rarely
transported far from the veins. It is true, that when in minute scales or powder, part of it is carried
off during floods, by adhering to the passing sands, but it is rarely deposited in available quantities,
except in close proximity to the veins in which it existed.
Notwithstanding the apparently large quantity of gold hitherto procured in the drift matters, from
the most remote periods, we may safely assume that it bears an infinitely small proportion to what yet
remains imprisoned within the rocks at no greater distance from the surface than has already been
reached by the industrious miner in other researches. The small amount of space occupied by the
ravines and valleys of excavation in metalliferous regions, compared with that remaining below and
between them, clearly proves the correctness of this opinion. But those who found hopes of wealth
upon gold mining should not, because of the existence of these vast stores, suppose that the mining of
them must of course be advantageous; on the contrary, the sad experience of the world has almost
always shown exactly the reverse.
The principal cause of this result is the enormous cost of blasting and removing the hard, intractable
vein-stone which, in most instances, embraces the gold, and this, too, in narrow, confined places under
ground. Even after this is brought out of the mine there arc additional expenses of large amount
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incurred in machinery, labor, and materials for reducing it to powder, and separating the gold with the
aid of mercury. When the mine is pursued to a considerable distance below the surface, there is a
heavy additional expense incurred in keeping it free from water, as well as in bringing up the mined
materials.
After all this is done the miner finds, in most cases, the proportion of gold is too small to pay the
expenses; and yet the allurements of gold mining are such as often to cause the parties to persist until
they are ruined, whilst they are each day expecting a brilliant result.
At the present time a few veins are said to be worked in Virginia, and other parts of the gold region
of our Atlantic slope, with reasonable profit.
In Peru and Chili gold is rarely obtained in this manner; indeed, the unproductiveness of the aurif-
erous veins in that region has given rise to a common saying there, that to work a gold mine is certain
ruin;" and they add, a silver mine is altogether uncertain, whilst a copper mine is certain gain."
In Siberia the veins are rarely worked with advantage, and almost the whole amount of gold ob-
tained in that country is procured from the drift.
Nature, in the latter case, does the mining, leaving it for man to separate the metal mixed with and
covered by the sedimentary matters. As these deposits are of moderate thickness, they are liable to
be soon exhausted of their gold when extensively worked. This has frequently occurred where the
proportion of metal was enough to pay the cost of working, as in Europe, in Asia, (except Siberia,) and
in most parts of South America, Mexico, and the Atlantic slope of the United States. It is but a short
time since the Siberian gold attracted attention, and being very extensively deposited, it still continues
productive.
Gold has been collected upon the western slope of the coast range of mountains in Upper California
for more than 40 years; but previous to the spring of 1848 it was not known to exist upon the Sierra
Nevada. The numerous false representations and romances, published in reference to the gold of that
region, and to the facility of gathering it, brings to mind the excitement that was produced more than
three hundred years ago by the abundance of gold which Pizarro and his fellow-brigands obtained in
their marauding expedition to Peru, by robbing the unoffending natives.
From all the knowledge we can gather at this day, it would appear that the narrow and deep
ravines in Upper Peru must have been rich in gold, and yet all worth working out, which had not been
collected by the natives, was soon exhausted by their conquerors, who made slaves of the conquered,
and compelled them to dig and wash for the metal. Much of it had been collected and was in
possession of the Incas and their subjects, as may be inferred from the statement of the quantity
offered as a ransom by the ill-used captive Inca, Atalhuapa; which was to fill with gold the room in
which he was confined to a mark on the wall as high as a man could reach. In a very short time his
part of the contract was nearly completed, when his cruel captors divided the spoils and put the Inca
to death. When melted up the amount was found to be equal in effective value to about nine millions
of our dollars. With all this apparent abundance of gold at the time of the conquest, the supplies im-
ported into Spain soon dwindled; and but for the discovery of certain veins extremely rich in silver,
the importance of Peru in reference to the precious metals would have declined at a much more rapid
rate than actually happened.
Pieces of gold weighing more than a few ounces have rarely been met with in nature, yet some of
considerable size have been recorded. The largest piece hitherto known was found in the drift near La
Pas, in Peru, in the year 1730, and weighed a little more than 59 lbs. Troy. It was not uniform in
composition, and the different parts varied in the proportion of gold from 75 to 95.8 per cent. Next in
size was found in Sonora, Mexico, a lump weighing 486 lbs. In Siberia, according to Humboldt, pieces
have been found also of large size; the largest weighed 27 lbs., and is in the Imperial Museum. Others
were found weighing as follows: 26-25 lbs., 16.64 lbs., 20 lbs, 1425 lbs., and 11 lbs. Troy. One piece
weighing 28 lbs. was found in 1828 at Reid's mines, Cabarras county, North Carolina, and another also
weighing 13 lbs.
It was often asserted in newspapers during the year 1849 that large masses of gold had been picked
up in California; 28 pound lumps were often reported, probably because one of that weight had been
found elsewhere, but no well-authenticated weight had been found as late as October. 1849, exceeding
81 OZ., or 6.75 lbs. Troy. More recently the newspapers in New York state the receipt of a lump in
this city, weighing 18 lbs. The largest yet received at the mint of the United States is the one above
noticed, weighing 675 lbs.
The similarity in geological structure of the chief gold regions is such that we may with reasonable
certainty expect its occurrence wherever this structure exists; or, in other words, wherever there are
extensive formations of talcose slates, accompanied to a greater or less extent by intrusive rocks. For
instance, Tyson, more than twelve years since, announced in the Transactions of the Maryland Academy
of Science, that the talcose slates of Maryland would be found to contain gold; and within two years
past it has been found in Montgomery county, and may be expected in the other counties to the north-
eastward. A few years later, Dana, when with the Exploring Expedition in California and Oregon,
noticed that the formations justified the expectation of the existence of gold, as has been since
realized. The principal gold region begins on the north, just about the southern limit of Mr. Dana's
opportunities of observation, because the party travelled along the Sacramento valley southward of
Mount Shasty.
It lies upon the western slope of the Sierra Nevada, which is a plain rising from the eastern edge of
the Sacramento valley to the summit of the Sierra, with an elevation of about 8000 feet in from 50 to
70 miles.
The chief rivers, rising near the summit, form almost torrents, with average rates of descent, of from
100 to 180 feet to the mile. The deep ravines which have been furrowed out by the flowing waters
have others opening into them, which have also their affluents 60 numerous that the whole flank is
everywhere intersected by glens and ravines, and presents the appearance of being composed through-
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GOLD.
out of isolated conical peaks, each rising higher upon approaching the summit of the Sierra; above the
ordinary height of which there are several very elevated volcanic peaks.
This flank from the valley upwards, to no great distance from the summit, is composed of argillite,
talcose, chloritix, and hornblende slates, with intrusive masses consisting of trap, porphyry, syenite,
serpentine, and other igneous rocks, which have been protruded through the slates in many places.
This constitutes the gold region (the main one) of California.
The outcrops of veins of quartz are very numerous throughout the district, and many of them, with-
out doubt, contain gold; but as late as October, 1849, none had been fully opened, except at one spot
on the Maripoosa river, an affluent to the southern part of the San Joaquin.
It is from the abundance of the fragments of quartz, which form these outcrops, and which are often
spread to a considerable width on each side of the vein, that the popular notion has arisen of a vast
superstratum of quartz rock, containing veins of gold, resting upon a substratum of talcose slates," and
which has nearly supplanted a former fancy equally incorrect; that of the gold having been scattered
over the country by volcanic action."
The rapidity with which the slate rocks are disintegrated, from the causes before noticed, and the
finely divided state into which they are resolved, causes them to be carried off with great facility by
the annual floods even in the present day; but during the greater inundations of the drift periods the
scouring out of ravines must have been much more rapidly effected. The result, however, up to the
present time, has been to form innumerable ravines, mostly having very steep declivities and of every
depth, from those of small size up to that of the north branch of the American river, which has in some
places worn its bed down at least 3500 feet below the adjacent highlands.
It is very probable that the rocks which once existed in the spaces now constituting the ravines, and
which have been broken up and removed to form them, formerly made up at least one-tenth of the
whole mass of the metalliferous district, within 1000 feet of the surface of the sloping highlands.
The quartz being the principal vein-stone, and resisting the action of atmospheric causes, is little sub-
ject to disintegration. It is, however, liable to be separated into fragments, such as are commonly
known as flint-stones, and which are found of all sizes in irregular angular fragments on and near the
surface of the ground, wherever veins or beds of this stone occur in the rocks beneath. Examples of
these are common in most parts of the world, and are familiar to every one in the region between the
great tertiary and cretaceous district of the Atlantic slope of the United States, and the eastern limits
of the mountains.
Whilst the metamorphic rocks are readily crumbled down and washed off by the waters, but few of
these fragments of quartz are carried off, other than those that chance to fall into ravines, through
which rapid streams of water flow; consequently, they continue to accumulate and extend upon the
surface.
This great amount of denudation may be considered practically, a natural mining operation upon a
most extensive scale. Nature has thus liberated the gold and left it among the drift in the ravines and
small valleys. The metal most abounds in the inferior parts of the drift, for the reason that during
former periods of greater inundations every thing of greater specific gravity than the heavier metals
was driven through and out of these ravines by the force of the waters. As the strength of these
floods became less the larger boulders were left, and finally those of smaller size and gravel and
sand.
It was conjectured by many who have not attended to geological pursuits, that this metal, whose
weight is so many times heavier than water, or even stony substances, had been washed from an
Eldorado at the summit of the Sierra Nevada; and many a gold-seeker searched as diligently for this
fancied spot as did the Spaniards in Peru, who thought 300 years ago it was near the summit of the
Andes. The weight of gold is such that whilst its gravitating force lends aid to the waters in forcing it
down the steep hill-sides into the ravines, it is amply sufficient to resist all currents which ever prevail
along them. This conclusion is fully confirmed by not finding gold, of any moment, in the drift, out of
the regions in which the auriferous veins occur, or at a distance from them. Such is the fact on the
affluents to the Sacramento and San Joaquin rivers from the Sierra Nevada; corresponding also with
what has been observed in every other gold region in the world. It is, however, possible that the pul-
verized portions of the metal were carried away to a small extent, adhering to the passing sands, as
before said.
An impression seems to prevail in this country that the drift in which the gold of California is found
is mainly sand, but this is rarely the case in California or elsewhere, except, perhaps, with the minute
scales from Africa, called gold-dust, which name is most inappropriately applied by many to the scales
and small pieces from California; where the drift of the gold region mainly consists of gravel and
coarse sand, filling the interstices between boulders, many of which are of large size. The beds of
the ravines are usually very narrow, and the drift resting upon them is from 2 or 3 to 16 feet deep.
In some places the bottom of a ravine expands in width, and the lessened velocity of the waters over
these during high freshets permits the deposit of sand, but these do not usually contain 80 large a pro-
portion of gold as an equal area of the bed of the narrow ravines.
The seemingly large amount of gold obtained in some of the ravines in California is to be attributed
to many causes, that may be briefly noticed.
1. The main gold region extends along the western flank of the Sierra Nevada a distance exceeding
500 miles, with a mean width of perhaps 35 miles. There is reason to believe that scarcely any ravine
of importance within this extent has escaped the probing operations of the gold-seekers. It was, how-
ever. chiefly upon the portion between the parallels of 36° and 40°, that the great army of operators
spread themselves during the year 1849. The area of this portion of the district is nearly 10,000 square
miles. and it is believed that within it the drift has been probed to the bottom almost every where upon
the beds of the ravines in search of rich diggings. The gold-digger is very rarely satisfied at any spot,
and is almost incessantly changing his location and digging holes in hopes of finding one of the rich
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spots that are often reported, but rarely found. By this means the best places for working are soon
found, and their treasures rapidly exhausted.
2. The existence of the gold was first ascertained in February, 1848; and the official letter of Gov.
Mason stated the number working in July of that year amounted to 4000. In the year following an
immigration amounting to 100,000 persons took place; and as the larger portion could find no other
means of support, they were compelled to occupy themselves at the gold-diggings. It is clear, there-
fore, that the operatives in this way within the first two years greatly exceeded the numbers that ever
flocked to any other auriferous district before known, in 80 short a period.
3. The gold liberated from the veins by the natural causes before noticed, has readily found its way
into the beds of the ravines. Their declivities are usually very steep, and they are narrow, especially
those of great length, and through which large bodies of water flow during the seasons of rains and
melting snows. The gold that formerly existed in the veins, within the space now occupied by these
ravines, has been left under and beside the streams which flow perennially through some of them, and
during part of the year through others.
It is apparent almost, but might be shown by calculation, that amounts greatly larger than seem to
have been procured from the drift of any of these ravines, might have been deposited without there
having been a single vein containing a workable proportion of metal A considerable quantity, it is
true, has been gathered from some localities, but upon calculating the solid contents of a vein which
once extended across any of those enormous ravines, we shall learn how small an average proportion
of gold in the vein-stone may leave a large deposit of metal. Take, as one of medium size in that
region, a ravine of 1000 feet deep, and whose acclivities are 30°, and we shall find, if we assume the
vein to have been only one yard thick, the destroyed portion would equal nearly 200,000 cubic yards,
weighing more than 4500 pounds per cubic yard. If it contained, at a mean, gold to the value of one
cent only in a pound of the vein-stone, this single vein should have left near it in this one ravine, gold to
the value of nine millions of dollars. And yet auriferous veins are very numerous in that region, 80
that gold occurs in the drift of almost every one of the ravines, which everywhere intersect the district.
From what has now been said, it is manifest that the circumstances under which the gold in the drift
was found in these gorges and ravines, have allowed it to be collected more readily than if it had been
mixed with the sedimentary deposits of wide valleys, where the proportion of gold must always be
small The sudden occupation of them by a vast crowd of operators might have been expected to pro-
duce a large amount in the aggregate; but to the parties themselves it has been far less than they
were led to expect, from the many false statements which have been continually published. The
results in Peru and Chili, where the gold occurred under circumstances closely resembling those in
California, must be expected in the latter country, and within a much shorter period.
The present irregular and unartistical mode of operating in California must, in a great measure, soon
cease of necessity. But upon a reduction of the price of labor in that country, systematic modes of
procuring the gold will be practised by skilful persons, under whose directions these deposits will be
worked over again, yielding perhaps more gold than was obtained at first.
The mode of calculation we have given demonstrates the absurdity of the statements so widely cir-
culated of the existence of vast rock formations of quartz containing gold to the value of $2 50 to
$3 00 per pound of the rock," as this vein-stone has been improperly termed. It is quite possible that
single specimens may have yielded these proportions, but such isolated instances should not be con
sidered as representing an average productiveness of a vein, which cannot be ascertained until after
working it to a considerable extent. They vary greatly in their course, so that a vein must either be
worked for many years from one point, or in numerous places, before any one can safely or prudently
state its average yield.
A vein has been opened on the Maripoosa river, an affluent to the San Joaquin, which is said, from
good authority, to present better prospects than usual.
In Brazil native gold is obtained in moderate amount from a recently formed conglomerate, called
there Cascalho, in which diamonds also occur.
Chili and Peru have been already referred to. Ecuador and New Grenada contain also portions of
the extensive gold region of the Andes.
Nearly all the principal mining districts of the world occasionally produce gold in some proportion,
(usually very small,) whilst being worked for silver, copper, lead, and other metals.
In Hungary and Transylvania a considerable amount is obtained and it is in the latter country that
the tellurets of gold occur, which were noticed among the ores of gold. It also exists in connection
with silver and copper in many of the mines of Mexico and South America. The mines of Saxony, and
of the Hartz mountains, produce a small quantity of this metal. It also occurs as native gold at Wick-
low, in Ireland, and in minute proportion in the lead ores of North Wales. Spain was celebrated for its
gold mines of former days, but produces a very little at present. Recently a gold region has been
discovered in Australia, which is represented in accounts from that country to be promising. In the
old-settled countries of Southern Asia and its larger islands, gold was procured in remote ages. They
produce very little in the present day.
A vein of quartz with gold was mined in France some years, in the valley of Oysans, but finally
abandoned, because of its poverty. Gold is occasionally collected in the eastern part of that country,
near a few streams.
Piedmont contains gold mines, some of which are still worked. Veins containing auriferous sul-
phuret of iron are worked at Macuguana, near Monte Rosa.
More than 20 years ago quite a gold fever was produced in the United States by the finding of this
metal in the northwestern part of Georgia. It was traced in a northeasterly direction into South and
North Carolina, and finally through Virginia into Maryland. The ravines being of moderate dimensions,
it did not require a long time to exhaust the most productive, and the veins are not extensively
worked.
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The geological structure of this gold region of the Atlantic slope is similar, in great measure, to that
of California and other districts producing gold. Talcose slates are the prevailing rocks which, whero
they extend into Maryland and Pennsylvania, are less interrupted by intrusive rocks, and as far as
appears are less metalliferous than those southwestward.
In addition to the large pieces before noticed, that were found in this region, many others of smaller
size have also been procured from the sedimentary deposits. At this time it is impossible to form a
correct opinion as to which of the two districts contain the richest veins, notwithstanding all that has
been said of California, where ravines have been scoured out to an enormous depth. Those.i the
Atlantic gold region bear but small proportion in size to the former. It is therefore quite possible that
those of California may have received their supply of gold from veins not richer in metal than those of
our Southern States. It is very probable that the average depth of the ravines in the main gold region
in California is ten times greater than those in the Atlantic district, and if 80, should contain a quantity
of gold in the same proportion, provided the veins be equally rich in each case. This mode of investi-
gating the industrial importance of gold regions should not be overlooked by those interested in the
subject.
It has been recently announced that gold has been discovered in the talcose slates of Pennsylvania,
and a few years since it was found in Canada.
The list of localities might be much extended, but those already given are sufficient to illustrate our
former observation in reference to the extensive distribution of gold upon the earth.
Extraction, separation, and assaying of gold-When gold occurs native in sedimentary deposits,
whose component parts are not held together by a cement. as in the cascalho of Brazil, there is required
at first but a small outlay of capital for collecting it, and the fact that individuals can operate inde-
pendently of each other, has usually caused a great rush of gold-seekers to every newly discovered
locality of this kind. These busy themselves in hunting out and digging holes in the drift to find rich
places, which are first worked, and at last these independent operators abandon the half-worked and
the poorer spots, to such as apply science, skill, and combinations of labor and machinery, enabling them
to obtain the metal from deposits too poor to reward the others. Such has been the case elsewhere,
and similar results must necessarily follow in California at no distant period.
The most simple means used for separating gold from the drift matters, after they have been dug up,
is to pick out the boulders and larger gravel, and wash the remaining gravel and sand with water in
a suitable pan or vessel. The pan in most common use is of thick tin-plate, about fifteen inches in
diameter at the top, and four inches deep, with sides inclined about 30° from the perpendicular. About
one quart of the materials is taken at a time, with a suitable proportion of water; and a rotatory motion
is given to the pan sufficient to throw out the sand, whilst the gold remains in it, water being added
from time to time. If any gravel remain in the pan, it is picked out. The gold remaining is usually
mixed with ferruginous grains, and is collected and dried. A very common mode of separating the gold
from these grains is, by blowing the latter out after being dried, which occasions a considerable loss in
the minute scales of gold. When, as is often the case, these grains consist of magnetic oxide of iron,
they may all be gotten rid of; but when, as sometimes happens, the specular oxide or chromiferous iron
are present, they cannot be removed in this way, because the magnet does not attract either of them.
The pan, in skilful hands, is convenient for the more locomotive part of the gold-diggers, or those who
work alone. These often also make use of small cradles or rockers, which can be transported upon
mules or horses.
The simplest form of the rocker is a quadrangular box, open at the top, and from three to eight, or
even ten, feet long, and ten to eighteen inches wide as well as high. At one end, which is slightly ele-
vated, there is a coarse sieve placed at the top to separate the gravel. Several small strips of wood
or iron are nailed across the bottom to check the too rapid motion of the solid matter towards the lower
end of the machine, so as to permit all the fine scales of gold to subside.
In using the rocker, the materials to be washed are thrown on the sieve, and water supplied by hand
or otherwise. A rapid rocking motion is now given, and the water escaping at the lower end carries
off the sand and earth, leaving the gold in the rocker with the ferruginous grains. These ordinary
rockers can hardly be considered an improvement upon the pan-washing and, in fact, any mode is
defective in which mercury is not used to separate the ferruginous grains without loss of the precious
metal. This may be used in any rocker made of or lined with iron in such manner as completely to
prevent the escape of the mercury.
The rocker in common use at the gold mines in Virginia is the only one that seems completely adapted
to the purpose, and is equally well suited for operating upon gold in sand and gravel, or upon vein-stones
reduced sufficiently fine for washing and amalgamating. It is made of large size, and effectually pre-
vents all loss of either gold or mercury. The sieves are of cast-iron, with holes of proper size. This
machine has been introduced into California, and found very effective.
The subjoined drawings represent the improved
2172.
d
rocker.
1
a
Fig. 2172 is a perspective view.
ri
a
a
2
Fig. 2173 is a longitudinal section through the
a
a
axis of the machine.
Fig. 2174 shows a cross section at hk.
a, Ribs of strong oak, about two inches square.
d
d, Staves screwed to the ribs, so as (with the
ends) to form a tight box, with a semi-cylindrical
a
9
bottom.
g
c, Cast-iron supports, upon which the box rests.
a', Cast-iron plates secured by spikes or screw-bolts to the two pieces of timber g. There are
elliptical holes in these plates, bevelled on the upper surface, 80 as to receive the lower terminal
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pieces of the supports c, and permits a rocking motion to be given to the machine by raising and depress-
mg the handle i, which fits into the socket h.
l, A perforated plate of cast-iron, with holes one-half or three-quarters of an inch in diameter, so as
to permit the passage of sand and small gravel. The retained gravel and stones are thrown out after
each charge has been washed. To facilitate this, a gate is placed at m, which may be attached by
means of hinges, or may slide in grooves at the sides.
k, A partition reaching from the top of the box to a little below the perforated plate l. Its use is to
prevent the escape of the water and earthy matters, which are thrown on the sieve or perforated plate.
The machine is then briskly rocked, by alternately raising and depressing the handle i, until the water,
which is constantly supplied, passes through the small opening o, clear, or nearly so.
The small openings shown in Fig. 2173 in the bottom of the box are closed with plugs, whilst the
2174.
2173.
m
a
n
d
1
a
d
d
d
,
o
a
&
g
operation is going on, and when the gold (or amalgam, if mercury be used) is to be taken out, the plugs
may be cautiously drawn out, so as to permit the water between the ribs to escape without losing the
precious metal.
The box may be of wood, but for permanent locations, it should be constructed of very thick sheet-
iron, or, rather, thin boiler-plate.
Native gold in veins of quartz is usually more or less mixed with iron pyrites, and sometimes with
pyritous copper. The ore, after being picked over by hand, is reduced to a coarse powder in a stamping,
or other mill, and agitated in a rocker with mercury, whilst the earthy matters are washed off with
water. In the north of Italy, principally at Macugnagna and Vinzone, there are many factories for the
separation of gold from an auriferous pyrites. The pyrites is crushed in horizontal mills to the size of
a pea, and then ground with mercury and water for twenty-four hours. These ores contain only from
0-00001 to 0-0005 of gold.
In all cases where mercury is used in separating the gold from impurities, the amalgam should be
pressed in a chamois skin or buckskin, which separates a portion of the mercury. What remains in
the skin is distilled in an iron retort and the mercury condensed in a receiver. The gold is left as a
spongy mass, which is melted to drive off any minute portion of mercury that may have remained after
distillation. If silver be present in the ore, it will be found alloyed with the gold.
It is unnecessary to describe in this article the processes for separating gold contained in the various
silver ores which are principally worked for that metal. In these the gold is obtained alloyed with silver
and other metals; and the means of effecting it will be described at length in the article SILVER (q. v.);
under which also the means of separating gold from galena will be noticed, because it is similar precisely
to those made use of in operating upon argentiferous galena. In fact, silver always exists in these ores.
Upon this branch of the subject it remains to treat of the means of determining the presence of gold
as it occurs in nature, and in what proportion to the accompanying foreign matters. There are numer-
ous ways of effecting this; but we shall only notice one very simple method, which, at the same time,
gives the most accurate results.
This is by the use of a glass tube, about one foot long, closed at one end, and whose internal diameter
is three-fourths or seven-eighths of an inch, not too large to be stopped with the thumb. This may be
about one-half or one-third filled with the auriferous sand or powdered vein-stone, and a few grains of
mercury, and a little water added after which the tube is to be well shaken for some time, so that all
the gold may be dissolved by the mercury. Water is then repeatedly poured in and out, whilst the
tube is inclined and gently shaken, in order to get rid of the sand. The gold, if any be present, will
have formed an amalgam with the mercury; the latter may be driven off by heating over the fire in
an iron spoon, or any other convenient iron utensil.
In assaying an auriferous pyrites in this manner, more accurate results are obtained if the pyrites be
previously roasted and reduced to a fine powder, although most of the gold may be obtained without
the roasting.
These tubes may be graduated so as to show the proportion to the bushel, or any other measure,
they will contain when filled to a proper height. One whose internal diameter is 806 of an inch (rather
more than 13 of an inch) would contain 111 of a bushel when filled with material to the height of six inches
Two such tubes, with a very small iron bottle containing mercury and a small delicate spring-balance of
little cost, and to weigh not more than three to five grains, may be secured in a wooden case, and furnish a
very portable, convenient, and accurate means of determining the proportion of gold in sedimentary
deposits or in vein-stones, if the means of powdering the latter be accessible.
The separation of gold and silver from other metals will be more fully treated of under the head of
SILVER; but we shall indicate briefly in this place the most efficient and accurate means of separating
gold from native alloys, as well as those artificial compounds usually met with.
Goldsmiths and other artists, in order to purify their filings and other matters containing gold alloyed
or mixed therewith, frequently do nothing more than melt it in contact with nitrate of potash, (saltpetre
but when it is desired to bring the gold nearly to purity, it is fused in a crucible, and then from two to
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four parts sulphuret of antimony (the lupus metallorum) gradually added. Sometimes it is necessary
to fuse the gold several times, in order to separate all other metals completely. Even silver may be
thus separated from gold. But, to get rid of the antimony, it must now be fused with nitrate of potash,
which completely separates it. Although we can thus procure gold in a very pure state, there is apt
to be a little loss; and if silver be present with other metals, it is an expensive process to recover the
silver from the mixed sulphurets which are formed.
The separation of gold from silver is completely effected either by means of pure nitric acid or nitro-
muriatic acid, according to the relative proportions of these metals in the alloy. If the metal contains
less than fifteen per cent. of silver, all the gold may be obtained in solution as chloride of gold. When
the proportion of silver exceeds 80 per cent., all the silver may be dissolved out by nitric acid, leaving
the gold unacted upon; its quantity may then be determined by weighing. If, however, great accuracy
be desired, it should be dissolved in nitromuriatic acid, and to the neutral solution, protosulphate of iron
added, which will precipitate the gold in a state of purity.
Alloys of gold, containing between fifteen and eighty per cent. of silver, should be fused with three
times their weight of lead, and the fused mass treated with nitric acid in sufficient quantity to dissolve
out all the metals likely to be present, except the gold. This fusion may be effected readily in a
porcelain crucible over an Argand spirit-lamp. If, however, platinum be present, there should be added
to the solution of gold in nitromuriatic acid, chloride of potassium, which will precipitate the platinum
as a double chloride. The gold may then be precipitated by protosulphate of iron in a state of purity
as before directed.
Jewellers often judge approximative of the proportion of alloy in gold, by means of the touchstone.
Stones of several kinds are used for this purpose, but pieces of polished trap or basalt are preferred.
A number of small bars or needles (not less than ten) are prepared of gold, having known proportions
of alloy. A mark or trace is made upon the surface of the stone with a piece of gold for assay upon
this trace a drop of nitric acid is placed; the same is done with the try-needles successively. The pro-
portion of gold is inferred to be the same as in that needle whose trace on the stone is similarly affected
by nitric acid.
Those who are skilled in the use of the blowpipe can readily detect with it the most minute propor-
tions of gold, silver, and other metals in ores or alloys; and in the cases of gold, silver, and copper
even the per centage of the metal may be ascertained with considerable accuracy, although the quantity
operated upon does not exceed one grain.
The method of using this important instrument, and applying it to the detection of metals, will be
given under the title of METALLURGY, (q. v.)
It is common to express the proportion of gold in an alloy by the words fineness. Thus, in the lan-
guage of assayers, when they say 18 carats fine, or 750 thousands fine, they mean that 18 parts out of
24, or 750 in 1000, consist of pure gold. The method of stating the fineness of gold by carats has been
discarded at the Mint of the United States, and at some of those in Europe.
The subjoined table gives the equivalents of carats in decimal parts, unity being twenty-four carats:
Carats.
Decimals.
Carats.
Decimals.
Carats.
Decimals.
1
0.042
9
0375
17
0.707
2
0083
10
0.417
18
0.750
8
0.125
11
0.459
19
0.792
4
0.167
12
0.500
20
0.833
5
0.208
13
0.542
21
0.875
6
0.250
14
0583
22
0.917
7
0.292
15
0.625
23
0.958
8
0333
16
0.666
24
1000
Uses of gold-The use of gold in coin, and the various applications of it to ornamental and useful
purposes in the arts and in domestic economy, will come in necessarily under appropriate titles. Here will
be noticed only its medicinal employment.
Preparations of this metal have been used in medicine for a long time, and were thought more cffi-
cacious in former times than in the present day, when mercury seems in great measure to have sup-
planted its use. Occasionally, however, it is revived upon the publication of new experiments. It is
yet retained in pharmacopoeias, but is little regarded by the medical profession. The compounds of this
metal used in medicine are the following:
Chloride of gold, in doses of
10
to
to
of
a
grain.
Iodide
"
"
to to 1/2
"
Cyanide
a
"
1/2 to 10
«
Oxide
"
"
t to 1 grain.
Purple powder of cassius
TO
to
T's
of
a
grain.
Metallic gold in powder, precipitated by protosulphate of iron, t to 1 grain.
All the above, except the oxide and metallic gold, are poisonous if several grains be administered at
a dose. The Homosopathic physicians also use preparations of gold in the infinitely small doses pre-
scribed by their system.
Annual supplies of gold-Professor Ansted, of London, made, in 1848 an estimate of the supplies
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GOLD.
809
of this metal from all sources, at the beginning of this century, which appears quite reliable, and which
reduced from pounds sterling to dollars, is presented in nearest round numbers as follows. Of course
minute accuracy cannot be expected in such a table.
Dollars.
Europe
900,000
Northern Asia
370,000
Mexico
1,200,000
New Grenada
3,250,000
Peru
530,000
Potosi and provinces east of the Andes, excluding Brazil
350,000
Chili
2,000,000
Brazil
4,750,000
Total
13,350,000
The same authority has furnished the following, showing the anticipated supply in 1849.
Dollars.
Europe, excluding Russia
968,000
Siberia
19,360,000
Asia, excluding Siberia
2,420,000
Africa
1,936,000
North America
968,000
South America
5,808,000
Total
31,460,000
The actual supply probably exceeds this estimate; for the amount from California before the close
of that year is not included.
It will be noticed that, in less than fifty years, the annual supply from America fell off about 27 per
cent. There has been an increase in Europe, and a considerable trade in gold from Africa, which had
ceased to export this metal fifty years since. Notwithstanding the falling off from South America, the
aggregate supply had increased nearly two hundred and forty per cent, mainly owing to the product of
gold-washing in the Ural and in Siberia. The supplies from this source began, for the Ural, in 1819,
when gold to the value of 437,000 dollars was produced, and they have steadily increased to the pres-
ent time, when it may be estimated at little short of twenty millions of dollars. The average from the
Russian possessions for 28 years to 1846 inclusive, is 5,540,000 dollars, but the product of the year
1846 was greater than the whole amount for the 10 years from its beginning in 1819 to 1829, (the
epoch of the discovery in Siberia,) viz. 18,702,750 dollars.
An addition is now to be made to the amount of gold supplied to commerce from the washings in
California. There is no small difficulty in forming a correct estimate in this case, in consequence of the
tendency to exaggeration 80 generally manifested by most writers.
The washings commenced in the spring of 1848, and, as has already been stated, the number of opera-
tors three months afterwards, was estimated by Governor Mason at 4000. They must have rapidly
increased, if one may judge by the vast emigration from all quarters, which was estimated to amount
to little short of 100,000 persons during the year 1849, and which still continues.
However great may be their dislike to washing and digging for gold, after they experimentally
realize the operation, the larger portion of them will, for a time at least, be compelled to engage in it
as a means of support, and thus swell the supply for the present year greatly beyond what can be
expected in any future year.
The whole amount from the commencement, for the two years ending upon the
14th May, 1850, received at the United States Mint from California, is
$15,675,452
Add amount purchased by artists or retained as specimeus
324,548
Estimated value of gold, excluding coin exported from California
5,000,000
Amount produced in two years
$21,000,000
It is very common to see estimates of much larger amounts than we have given; and upon the arri-
val of a steamer from the Isthmus of Darien, with the mail or passengers, from California, we have
always an estimate of 2 or 3 times the quantity of the precious metal, which is subsequently stated in
the published returns of the United States Mint; where, it is manifest, nearly all received in this coun-
try is sent for coining.
The allowance we have made for that sent from California to foreign countries, is far more likely to
be over than under the actual sum, as might be shown if our limits would permit.
There are reasons for believing that of the 21 millions produced, about 15 millions were collected
during the year 1849. From the number of persons who will be engaged at the washings during the
present year, (1850,) it is possible that the amount collected may reach 20 millions, although the
exhaustion of many of the most productive localities during the last year renders it not very likely,
notwithstanding that the number of operators may be larger. The exhaustion of most of the ravines
containing gold in available proportions, at the present or even at a much lower price for labor in Cali-
fornia, will probably happen during this year, and many persons will either occupy themselves in other
pursuits within the country or leave it. We may expect, therefore, a considerable falling off in the
supplies for 1851 and 1852, and thereafter; and that it would not be prudent to expect more than 10
or 12 millions per annum after the last-named year, unless, contrary to experience in every other
gold region hitherto explored, the rich quarries of gold" of some writers, or, in other language, the
veins of quarts containing gold in that region, shall prove highly productive.
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GOLD-BEATING.
The report of Mr. Tyson's Geological reconnoissance, published among the documents of Congress,
fully confirms the observations of Prof. Ansted, in the paper before quoted, in which be says, It is
quite certain that the deposits, (in California,) if so rapidly worked, must be rapidly showing symptoms
of exhaustion, for such deposits are neither inexhaustible, nor are they soon recruited; and the mines,
vaunted as they now are, will be found to resemble other mining operations, and can by no means be
expected to yield, continuously, large supplies without great labor, risk, and expense."
Anticipating supplies of gold to an immense amount from California, many persons have occupied
themselves in speculating upon the effects likely to result in regard to the value of property generally.
This subject belongs, properly, to our article MINT, (q. v.) but it may be stated in this connection, that
all fears of extraordinary reduction in the value of gold from this cause are altogether groundless.
The labor and other items of the cost of procuring gold in California, as in all other gold regions, is
so great as to guard most effectually against over-production. A very small reduction in its commer-
cial value would materially lessen the production in the many localities where the expenses are even
now little, if any less, than the value of the precious metal produced.
GOLD-BEATING is the art of preparing what is well known under the name of gold leaf, in which
gold is hammered or beaten into plates, whose average thickness at the present day may be taken at
350000 of an inch. An art which affords so remarkable a result, in rendering tangible a space which
is invisible, well deserves mention here.
The extreme malleability and ductility of gold, no doubt, brought an art like this into use very soon
after the metal was known, and at a very early period in the world's history. The overlayings"
which are spoken of in the Book of Exodus (chap. xxvi., dc.) were, most likely, of gold-leaf in some of
the instances at least such appears to have been the opinion of the writers of the Septuagint. The
gilding of Egyptian remains, which many of us have seen, and which are, undoubtedly, of leaf in a re-
spectable at tenuation. may carry the art back to a remoter epoch even. It appears to have been no novelty
to the heroes of the Trojan war, or, at least, to the Rhapsodists, who, seven and twenty centuries since,
sang their deeds; and, finally, Pliny, about our era, gives particulars whereby we may judge of the state
of the art, then long and extensively applied.
This author has, in this respect, been either hastily read or partly misunderstood, and thus errors of a
very opposite character have crept into statements made or handed on by respectable authorities. Thus,
Buonarotti, for instance, infers that the least thickness of gold-leaf the Romans could make was twenty-
two times greater than ours; while Ure, apparently quoting Pliny, would make the modern gold-leaf
eleven hundred times more thin. In point of fact, the reduction of Pliny's measures, will give, as the
average thinness of Roman gold-leaf, 78727 of an inch, (for he says that it is not the thinnest,) or about
three times as thick as we make it now.
No account remains of the methods practised by the ancients for this purpose; but there can be
little doubt that they were similar to, though with less efficient means than, our own, which are more
the result of patience and skill than of science or civilization. The first notice that we have of the
process dates back to the ninth century, when a German monk, Theophilus, speaks of the employment
of parchment as an envelope to protect the surface, and of the use of red ochre or chalk (our workmen
at this day very often call it talc) to prevent the leaves from sticking. Parchment, or vellum, must
soon have been found too thick to answer the end perfectly; but the introduction of what is called gold-
beaters' skin, (by the French artists, baudruche, and by the Germans goldschlägerhaut,) which is pre-
pared from one of the membranes (the peritoneal) of the larger intestines (the сœсит) of the OX, is of
uncertain date. It is affirmed by some to have been originally an Irish discovery; but the precise mode
of preparation is kept as a sort of mystery by the few persons who furnish the article for gold-beaters.
The general principles of the mode are, however, very well understood. The particular secret would
hardly be worth the trouble of penetrating.
To manufacture gold-leaf, the metal is required in theory to be in a state of purity. All alloy is at
the expense of malleability. But in practice, this is rarely, if ever, attained, and the usual fineness is
that of coin, which in France and the United States is ninety per cent.; in Great Britain 911 per cent.
and in Bavaria, where the principal amount of gold-beating in Germrny is done, 9710 per cent. fine.
In France it was stated, thirty years ago, that the most approved practice was to mix equal parts of
old Spanish coin and pure gold, which would result in an average proportion of 95% per cent. fine.
Below 75 per cent. fine, the manufacture would be, in labor and waste, a losing business.
The principal aim of alloying, when it is done of design, seems to be in the production of a variety
of color-silver making the leaf pale, copper deepening the tint. These effects are more particularly
noticed in the article GOLD; they are similar in the leaf as in the more solid masses; only in the state
of tenuity, the green and purple tinge spoken of there is more easily excited and more vividly displayed.
Whatever may be the character and degree of alloy, the manipulations of the gold-beater are the
same in kind, and will be now briefly described.
1. Casting.-The metal is placed, with a little borax to promote fusion, in a black-lead crucible, or
crucibles, and set in a furnace. When perfectly melted, it is poured into cast-iron moulds, three or
four inches long, three-quarters of an inch wide. and about half an inch deep, and holding each about
one thousand grains of metal. These moulds are made with faces a little concave, to allow the cast to
draw easily; and before pouring, they are heated, and rubbed with linseed-oil or tallow on the inside,
to drive off moisture and promote an easy separation. When sufficiently cool, the ingot is taken out,
and re-heated in an open fire, or a small annealing-furnace, by which it is softened, and the adhering
grease driven off.
2. Laminating.-In older times, this was effected entirely by the hand-hammer now a flatting-mill
or laminating rolls are employed. The French still use, however, a preliminary forging upon a steel
anvil, (of three inch by four inch sides,) with a hammer of about three pounds weight. The face of
this hammer is about one inch and a half square, and its handle about six inches and a half. With
this they bring down the thickness of the ingot to one-sixth or one-seventh of an inch. The English
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GOLD-BEATING.
901
perform the whole of the operation in the rolls. As the success of the work and the excellence of the
leaf ultimately depend a good deal upon the uniformity of the lamination, care is taken to use a proper
and accurate machine. These machines have been successively improved; until now there is little, if
any thing, left to be desired. During the hardening processes of lamination and forging, if the latter be
employed, the riband has to be frequently annealed, to prevent cracking. Formerly, the lamination
was thought sufficient which had brought the thickness down to 3'3 of an inch, with a width of one inch
and the balance was done by hand, cutting the riband into lengths of one inch and a half, piling twenty-
four of the lengths evenly together, and forging them all at once till they came square. This is the
practice with some of the French and German gold-beaters to this day: but others, having access to
more perfect machinery, continue its application to the lamination until the thickness is brought to about
700 of an inch. As dimensions like this cease to be appreciable, the degree of lamination is estimated
by weight; and the direction usually is, to bring it down until a square inch of riband weighs six grains
and a half; in this state it is ready for the beating proper.
3. Beating.-The implements and fixtures for this are, an anvil, hammers, skins, shears, parting-
knives, &c. The anvil is a block of marble, weighing 250 or 300 pounds, or more, at pleasure, with
a face of nine inches to one foot square, carefully made even and smooth. This is set in a frame wood-
work, strong and solid, and upon a firm foundation. A ledge, five or six inches high, runs round three
sides of the frame; to the remaining side an apron of leather is attached, which is lifted by the work-
man. The object of all this is to catch and retain fragments of the precious metal. The hammers are,
ordinarily, four in number, varying in weight. Their faces are from three to five inches in diameter,
and slightly convex. The weight of the first or flat hammer is about fifteen pounds; the second (which
the French term the commencing-hammer) weighs from six to eight pounds; the third, or spreading-
hammer, with a smaller face, and more convex, weighs about five pounds only; and the last, or finishing-
hammer, is again a heavy one of ten or twelve pounds, with quite a convex face. The skins are of
parchment and vellum and the intestine already spoken of, cut (the two former) into squares of about
four inches, and (the last) of five inches. Besides these, there are packing-boxes, also of parchment,
made on a form, and cemented together, open at two opposite ends, and in pairs, so that one will elip
into the other, by which the open ends are closed. The knives are pieces of cane, set into a frame, both
four-square and cruciform, with sharpened edges that divide the attenuated leaf, better than any other
implement, by pressure downwards only. When the leaf becomes very thin, any other motion would
drag it.
Provided with these and other tools that do not require special mention, the workman lays off the
riband (which comes from the laminating, as nearly as possible, one inch in width) into lengths also of
one inch. This he does with dividers or a scale, and cuts off, afterwards, with shears. This is on the
supposition that the rolling has been uniform, and equal surfaces therefore should give equal weights.
He then arranges these squares into piles of generally 150 pieces, interposing between each leaf a
piece of the vellum before spoken of, and placing the gold-leaf as near as may be in the centre of the
vellum, with their edges even. About twenty extra-vellums are placed on top and at bottom, and the
pack is then of proper size to be pushed smoothly into one of the parchment envelopes, which is then
in its turn pushed into its mate, and the whole thus enclosed on all four sides. The pack is then laid
on the marble anvil, and beaten until the small gold-leaf is extended to the size of the vellum. It is
in the judicious uniformity of direction and force of the blows that the skill of the workman is displayed.
Great dexterity is, in fact, attained: the hammer is shifted from hand to hand for relief without inter-
fering with the regularity of the stroke; and when it is recollected that the absolute effect of the aver-
age hammer with the average blow is equivalent to the steady pressure of about 2800 pounds on the
square inch, there will be seen to be need for discretion in the application of such a force.
During the beating. the pack is frequently turned, 80 as to beat on the bottom as well as the top, (as
a skilful workman will do without losing the stroke,) and also folded or rolled in the hand, to secure a
proper detachment of the surfaces. It is also opened from time to time to watch the effect, and shift the
leaves from the centre to the outsides, that the pressure may be uniform. When the gold has been
extended to the size of the vellums, about sixteen times its original dimensions, it is taken out, cut up
into four squares, repacked as before, only with gold-beaters' skin instead of vellum, and beaten over
until similarly extended again. The caution of folding the pack to loosen the leaves is more necessary
even now than before, and 80 of opening and shifting. When it has attained the size of the skins, it
is removed, parted into squares again, but this time with the cane, repacked and rebeaten as before
into leaves of three to three and a half inches square. It is estimated that the aggregate surface of the
leaves is now 192 times larger than it was originally; and their thickness may be taken at 140hno of
an inch, which is about the average of English gold-leaf, and corresponds to an extension of about 100
square feet to the ounce. But the operation is frequently carried further by repeated beatings till an
ounce is extended over 160 square feet, corresponding to 8 calculated thickness of of an inch
nearly. The French gold-beaters claim-and their statement of weight worked on and number of leaves
produced warrants the claim-to carry it down ordinarily much further than this; and our statement
at the beginning of 330000 of an inch is, probably, even within the average result, and much within
the possible limits, of malleability, if these were, without regard to expense of time and waste of metal,
the only points to be reached.
The French workmen are also very precise in the number of pieces, both of leaf and of baudruche
and vellum, which go to the packs in each of the five several steps that comprise their beating. As
the fruit of experience, no doubt, they have ascertained the number which best suits the respective
implements. The English and Germans pack in different numbers, it may be supposed with the same
reason; but the principles of the operation are, in all, the same.
When the leaf is considered as finished, the last thing is, to put it in the square books, such as we
see in commerce. These are made of smooth paper, frequently reddish-colored, on purpose to heighten
the lustre of the gold, and well rubbed with Armenian bole, to prevent adhesion. There are two sizes;
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GONIOMETER.
one about 41, the other 34 inches square. The pack, withdrawn from its parchment envelopes, is held
by one of its angles; and, with a pair of wooden pliers, each leaf is withdrawn, and laid, aided by the
breath, upon a leathern cushion, where, with the cane knives, it is parted at once or successively into
four pieces, the size of the book. These pieces are then similarly transferred to the book, each between
separate leaves. The book holds, very uniformly, twenty-five leaves of gold. When filled, it is pressed
hard with a piece of wood of its own size, 80 as to bring its edges close; and with a piece of linen any
projecting pieces of gold-leaf are readily wiped off. Afterwards, the books are put up in packages
of a dozen ordinarily, for sale.
The French artists allow between three and four days for finishing four ounces of gold. They esti-
mate the loss in trimmings, waste leaves, &c., at fifty per cent, and consider the remaining two ounces
poids de marc, (964-10 grains English,) as yielding 12,600 leaves of the smallest size; but there is no
authentic experiment of weighings and measurings in this respect.
The parchment employed is used as it comes from the manufacturer, only cutting out of the sheets
those parts, of suitable size, which are softest and of most uniform thickness.
The vellum, which is procured of the finest and softest, is not further treated than by well washing it
in cold water, drying it in the air under a press, and then powdering it with finely calcined and reduced
selenite. Whether the implement used for this has any special influence will not be affirmed or denied;
but the uniform practice, in France at least, is to use a hare's-foot.
The preparation of gold-beaters' skin, from the colon of the OX, has been already spoken of as a secret
endeavored to be maintained by the few who furnish the article. Whatever their processes may be,
the gold-beater is accustomed to test and treat it still further for himself. Thus, he first sweats it, by
placing it between a fold of foolscap; making a pile of many pieces, he treats it to a hearty hammering
until it ceases to give out any grease to the paper. Next, he moistens it with an infusion of nutmeg,
cinnamon, or other spicy aromatics, with the view of preserving it, dries it in the air, moistens again as often
as he sees fit, and finally dries and presses it for use. Since the introduction of creosote, this (as well as
may be judged from the odor of some recent skins) has been applied, and no doubt more effectually.
After the skins have served some time, (some seventy or eighty beatings, for instance,) they become
inspissated, or wiry, or both, and no longer allow the proper extension of the gold. This may be cured
by laying them a half day between leaves of paper wetted with Rhenish or Moselle wine, or even vine-
gar and water. When thoroughly moistened, they are placed between layers of parchment, enveloped
and beaten until dry. This beating frequently takes a whole day. They are then powdered with
selenite. and fit for use.
While yet fresh, the skin is very liable to be affected by moisture which it absorbs from the atmos-
phere. They must be, therefore, always dried before using, which in France is done by heat in a
screw-press. Care is taken not to desiccate too much, which withers and causes it to crack under the
hammer.
The methods which have been described here are also applicable in their measure to silver, copper,
and platinum.
A sort of gold-leaf, called party gold-leaf, is sometimes used, made with a combination of gold and
silver. Separate leaves are taken of these metals, the silver being about three times as thick as the
gold, heated and laminated together, so as to produce an alloy or welding of their surfaces. The
resulting party-colored riband is then beaten as if it were all of gold. Its extensibility is, of course,
not so great.
There is another false gold-leaf, which is better known as Dutch gold-leaf. It is, in fact, a riband of
brass, wash-gilded, (see GILDING,) sheared into leaves, and then beaten in the manner, and with more or
less of the precautions, that have been described. When new, it is difficult to be distinguished from
true gold-leaf; but it is soon tarnished by the air, and is unfit for any gilding that is not to be varnished.
GONIOMETER. (Gr. yours, angle, and METPOV, measure.) An instrument for measuring angles, and
more particularly the angles formed by the faces of crystals. The instrument, chiefly used by miner-
alogists, was invented by Dr. Wollaston. It consists of a brass circle graduated on the edge, and fur-
nished with a vernier, by which the divisions may be read correct to a minute. The circle moves in a
vertical plane, and is supported on a stand. The axis of the circle is a hollow
2175.
tube, within which is a smaller axis, fitting 80 tightly that when turned round it
A
carries the other axis, and consequently the wheel, along with it, unless the latter
E
is purposely prevented from moving. The interior axis is furnished with a milled
head a, and the exterior with a milled head b; 80 that when the head a is held
B
and b turned, the circle may be moved independently of the smaller axis; and
when b is held and a turned, the smaller axis may be turned independently of
the circle. Attached to the end of the smaller axis is a sort of universal joint,
capable of being fixed in different positions by means of screws. The crystal to
be examined is attached to the joint at c by a little soft wax, and placed so that
its edge shall be parallel to the axis of motion; which adjustment is obtained by
placing it 80 that the image of some horizontal object, as the bar of a window,
successively reflected from the two faces of the crystal, coincides with another
horizontal line seen by direct vision. When this adjustment has been made, the
instrument is turned till the horizontal object is seen reflected from one of the faces. The smaller axis
is then held fast, and the other turned till the index of the vernier points to the zero of the graduated
limb. The circle is then turned round, along with the smaller axis, till the same object is seen in the
same position by reflection from the other face of the crystal; when the arc passed through by the
circle is obviously the supplement of the angle formed by the two faces of the crystal. In order, how-
ever, to avoid calculation, the supplements of the angles are marked on the limb, 80 that the angle to
be measured is read off immediately.
The name Goniometer is also applied to a surveying instrument, somewhat similar to a Theodolite
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GOVERNORS. The theory of the operation of the common centrifugal governor will be found at
p. 545, under the head of ENGINES. We here introduce various forms of application of the same princi-
ples, together with other contrivances to accomplish the same object. All the work required of the
governor, Figs. 2176, 2177, 2178, is to ring a bell, and to indicate upon a dial the velocity of rotation of
millstones.
This mechanism consists of a vertical wrought-iron axis A A, revolving in bearings BB, bolted to the
wall of the mill, and carrying, towards its upper extremity, a pulley C, which receives motion from the
main driving-shaft. To this axis is fixed a brass socket b, to which are jointed the two flat arms a a,
terminated by the governor balls, and attached, about the middle of their length, by the two double
links cc, to the sliding-socket d, made in halves and connected together by two small bolts. To this
latter are also attached the two slender vertical rods ee, which traverse the pulley C, and convey the
action of the governor to a sliding-disk D, provided with a projecting arm or catch, of such length as to
come into contact, should the machinery exceed or fall short of its proper speed, with either of the two
levers ff, which have their common centre of motion in a short vertical axis, and are attached at their
opposite ends by slender wires to two sockets mounted upon a horizontal axis E; each of these sockets
carries a bell, which, by the arrangement described, is rung when the catch on the disk D strikes either
of the levers ff.
To the sliding-socket d is fixed a forked rod,
having one of its branches formed into teeth
like a rack; this rack geers with a small pin-
ion, Fig. 2178, carrying upon its axis an index,
which points out upon the graduated dial F,
2176.
the speed at which the millstones are revolv-
ing. Thus, should the velocity of the prime
mover relax, the vertical axis A partaking of
this diminished motion, the balls collapse, the
B
socket d is pressed downwards, and the rack
&
causes the index to move from right to left.
The opposite effect is produced by an increase
of the speed; (these different positions being
indicated by the dot lines in the figures.) At
the same time the bell is sounded by the ap-
paratus which surmounts the governor; and
2178.
the attendant, by a glance at the dial, is made
aware of the change in the velocity of the ma-
chinery, for which he has to compensate by
altering the degree of proximity of the upper
2177.
and lower stones. It is sufficiently well known
to our mechanical readers that the action of
the governor is in no way affected by the
weight of the balls, further than that these
should be made of a size proportionate to the
A
resistance to be overcome; accordingly, in the
case now before us, the work which the gov-
ernor is destined to perform being very slight,
the balls may be made of extreme lightness.
Fig. 2179 is an example of the original form
of the governor as introduced by Watt. The
distinguishing peculiarity of this form of gov-
ernor consists in the connecting links cc, being
situnted overhead, and attached to the arms
aa, by prolongations of the latter, which pass
through a square part of the upright spindle
A, to which they are both jointed by one pin.
2180.
When at rest the balls are usually received
into arms g g, curved to suit their surfaces, by
which means the rods are relieved from all
unnecessary strain.
Fig. 2180 is a representation of a centrifugal
governor, adapted to a small high-pressure
crank-overhead engine. In this species of en-
gine the governor is usually made to revolve
in a short column B, cast in a piece with a
forked bracket embracing the crank-shaft, and
its spindle A A is driven by a pair of bevel-wheels from the crank-shaft. The spindle is surmounted
by a double brass socket b, attached to it by means of a pin; and to this socket are jointed the arms a a,
which, as well as the connecting links c c, are, in this example, finished in the lathe. The sliding brans
socket d, to which the lower ends of the links cc are connected, is formed with a groove, into which is
inserted the forked end of a lever D, having its centre of motion in a small wrought-iron column bolted
to an arm projecting from the column B. From the opposite end of this lever depends the slender
rod e, connecting it immediately with the throttle-valve lever, which, by this simple construction, is at
once made to rise or fall, as the balls collapse or diverge in obedience to the varying speed of the
engine. This is a type of the most common form of the centrifugal governor in use at the present day.
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904
GOVERNORS.
Fig. 2181 is an example of a very excellent arrangement of the conical pendulum governor which is
frequently adopted in highly finished engines. The peculiarity of this form consists in the connecting-
rod e, being attached directly to the sliding-socket d, without the intervention of the forked lever. For
this purpose the upper portion of the spindle A A is bored out truly cylindrical, to a point somewhat
below the range of the sliding-socket d. This last is attached by means of a cotter to a small cylindri-
cal hollow piece, which fits accurately into the interior of the spindle, and is consequently made to rise
and fall with the socket d, a long slot being formed in the spindle to allow the cotter to traverse up
and down. The lower end of the rod e is jointed to this interior piece by means of a swivel, 80 as to
rise and fall with it, without being affected by its rotatory motion. At the top of the governor spindle,
the rod e is guided in its motion by being made to pass through the small brass vase which surmounts
the whole apparatus, and should it be required to be of any considerable length, the necessary rigidity
may be imparted by fixing a weight to it, as shown in the figure.
2186.
2189.
2187.
2190.
2191.
As in the example last under notice, the arms and links of this governor are finished in the lathe, as
also the double cup g, into which the balls are received when the engine is at rest. In Fig. 2181 the
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905
balls are shown in section, in order to exhibit the mode usually adopted for adjusting their position upon
the arms a a.
The form of governor represented by Fig. 2182 appears to be worthy of favorable consideration, on
account of the principles on which it acts, and of the extreme simplicity and economy of its construction.
The vertical spindle A A, which may be set in motion either by a pulley or by bevel-wheels in the
usual manner, is surmounted by two equal horizontal arms a a, furnished with stops at their extremi-
ties. The governor balls run freely to and fro upon these arms by means of internal friction-rollers, and
are drawn towards the common centre in the spindle A, by means of cords or steel ribands ii, passing
over two pulleys at G, and attached at their lower ends to the sliding-collar d, in which works the
forked end of the lever DD, which conveys the action of the governor to the throttle-valve. A spiral
spring embracing the vertical spindle presses at its lower extremity against the sliding-collar d, and its
pressure is regulated by a sliding-stop h, which can be fixed at any required elevation upon the spindle
by a set screw.
The stop h having been set 80 as to cause the spring to press down the collar d with any approved
force, and the throttle-valve opened to any required extent, the engine is set in motion. Should its
speed exceed the stipulated rate, the increased centrifugal force will cause the two balls to diverge,
and raising the collar d, will partially close the throttle-valve and diminish the supply of steam, when,
the motion being checked, the spring will press down the collar and cause the balls to collapse until
the desired rate of motion is obtained.
2182.
2179.
2181.
&
3
A
D
D
0.0
A
A
P
2183.
2184.
D
2185.
H
H
D
a
The degree of force exerted by the spring will always require to be adjusted to suit the nature of the
work thrown upon the engine, because a small quantity of steam only will be required when the work
is light, and a larger quantity when it is heavy. while the speed should in each case be the same, which
conditions can be fulfilled with great facility and admirable precision by the use of this kind of governor.
Fig. 2183 represents a simple and compact modification of the centrifugal governor. Here the balls,
instead of being suspended upon arms of a length proportioned to the velocity at which the engine is
required to move, are fitted to traverse from and towards their common centre in the spindle A, upon
the arms HH, which revolve with the latter, and are formed into circular arcs of a curvature deter-
mined by the same circumstances with the length of the suspending arms in the ordinary governor.
By this means it is obvious that the horizontal plane of the rotation of the balls will vary with the vary-
ing speed of the engine, in precisely the same way as in the conical pendulum governor; and the ver-
tical motion thus generated is transferred directly to the sliding-socket d, which commands the throttle-
valve lever. For this purpose, it is necessary that each of the balls should be made in halves and
riveted together with a wrought-iron pin, as shown in the section, Fig. 2183; a space being left between
the hemispheres to admit of the slotted arms a a, which are cast in a piece with the sliding-socket d,
and through which the connecting pins are fitted to pass freely, but without allowing any play.
The last variety of the centrifugal governor which remains to be noticed is that represented in Figs.
114
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GOVERNORS.
2184 and 2185 the former being a sectional elevation, and the latter a plan of a governor constructed
by M. Bourdon, of Paris, the peculiarity of which consists in the axis of rotation being horizontal instead
of vertical The main advantage proposed to be attained by this system is the more convenient trans-
mission of the motion of the prime mover, whether by wheel-work or by pulleys. The principle of its
action is the same as that of the common governor.
The spindle A A is of cast-iron, the part to the left being hollow, while the middle portion is formed
into a species of open frame-work, enclosing the principal part of the mechanism. It revolves in ordi-
nary plummer-blocks B B, and is set in motion by the cone pulley C. The arms a a which carry the
governor balls, are supported upon a short axis working on the points of two steel pins, screwed into
the central part of the spindle and secured by jam-nuts; this axis carries also a toothed sector c, work-
ing into a similar sector upon another short axis to which is fixed a lever d; the slender connecting-
rods jj, traversing the hollow part of the spindle, and supported by the guides kk, serve to convey the
motion of this lever to the throttle-valve geer, which is provided with suitable arrangements for adjust-
ing the action of the governor upon the throttle-valve.
The air-reservoir or bellows governor.-This apparatus is of French origin, a patent having been
granted to the inventor, M. Molinié, of Saint-Pons, in 1838. The principle on which its action depends, con-
sists in causing the engine to force a quantity of atmospheric air into a reservoir with a movable cover
through which the air escapes, the aperture being 80 regulated by an adjustable valve, that it shall
only escape at a given rate. Should the speed of the engine exceed or fall short of the prescribed
limit, the air is forced into the reservoir faster in the one case and slower in the other than it can escape
through the valve; consequently the movable cover is raised or depressed, and, by means of suitable
connections, partially closes or opens the throttle-valve. The advantages proposed by this system are,
first, greater regularity and steadiness of action than is attainable by the common governor, combined
with equal delicacy; and, secondly, a more considerable range or amount of motion available for the
purpose of regulation.
Fig. 2186 is an external elevation, Fig. 2187 a sectional elevation, (on a plane at right angles to the
former,) and Fig. 2188 a sectional plan of this apparatus.
The working parts are enclosed within a cylindrical vessel, the sole being formed of a cast-iron disk
A, supported upon four small columns aa, and the cover, of a cast-iron capital or cornice C; these are
bound together by the four pilasters BB, having recesses formed on their edges for the reception of
cylindrical sheet-iron panels, which thus admit of being removed at pleasure, when it is necessary to
examine or repair the internal parts. In Figs. 2186 and 2187 these panels are shown partially re-
moved.
Two small wrought-iron columns DD are also fixed to the sole-plate, and serve to support a cylin-
drical cast-iron vessel E, the bottom plate of which is provided with two apertures guarded by the
flap-valves d and g, which open alternately for the purpose of giving admission to the air which is forced
into the receiver E by the double bellows F F; these are respectively supplied with air from the sur-
rounding atmosphere by the apertures b and f, similarly furnished with flap-valves, the former being
situated in the sole-plate A, and the latter in the movable piece G; the stream of air generated in the
lower bellows passing through the upper by means of an elastic leather tube or copper pipe c. The
cover of the fixed receiver E is formed of a movable cylindrical disk H, attached to the former by
leather, in the manner of an ordinary bellows, and thereby admitting of being elevated or depressed,
according to the degree of condensation of the air within the receiver; this is regulated by means of a
small conical hole h, guarded by a pointed screw i, properly secured from turning, after being adjusted
80 that the air forced into the receiver when the engine is at its normal velocity, shall just have liberty
to escape, and consequently hold the movable cover suspended. Motion is communicated to this ap-
paratus by means of two rods 11, fixed to the movable intermediate piece G, and attached by means
of the connecting-rods m m to cranks formed on the shaft I, which is set in motion by a belt from the
prime mover working over the fast and loose pulleys JJ. A round rod K, screwed into the movable
cover H, serves to convey the motion generated by the governor to the throttle-valve or sluice-geering,
as the case may be. On this rod is fixed a ball L, which, for the sake of adapting the governor to the
varying circumstances in which it may be placed, is usually made hollow and partially filled with lead.
Fig. 2189 is a representation of a mode employed by M. Molinié, for rendering his governor most
advantageously applicable to regulating the supply of water to a hydraulic motor. Besides the regular
sluice-gate, he makes use of an additional valve N', to which, by means of the cord and pulleys shown
in Fig. 2186, he attaches the governor. The face of this valve is bent into a cylindrical form, and it is
jointed by rods to a central point considerably behind the sluice-face O'. By this means the strain
arising from the pressure of the water against the back of the valve is counteracted, and the action of
the governor rendered sufficiently delicate.
Fig. 2190 represents the connection of this governor with the throttle-valve of a steam-engine.
The efficient operation of this governor depends entirely on the perfection of the mechanism by which
the escape of the air from the receiver E is regulated. The simple contrivance detailed is altogether
inadequate, as it is neither self-adjusting nor theoretically perfect in any circumstances, as will be ob-
vious from the consideration that the volume of any fluid escaping by a given orifice depends not only
on the section of that orifice, but also on the velocity of the escape; 80 that the higher the velocity, the
aperture remaining the same, the greater will be the volume of issuing fluid.
To compensate for this circumstance, M. Molinié has devised an arrangement at once simple and
effectual. Instead of the pointed screw i, he makes use of a conical pin i', see Fig. 2194, which is at-
tached by nuts to the movable cover H. It is fitted to move in the interior of a brass tube h', fixed to
the stationary part of the air receiver, and close at the bottom, while the top is pierced with a hole of
the exact size of the thick part of the pin. The air passes by an adjustable aperture into the interior of
this tube; and according as the cover H is more or less elevated or depressed, the area of the aperture
of escape is proportionally increased or diminished. By this ingenious contrivance, not only is the the-
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907
oretical defect above alluded to corrected, but a great additional advantage is obtained in the more
rapid and energetic action of the governor.
Figs. 2191, 2192, and 2193 represent two different modifications of the vane governor. The principle
of its action consists in the atmospheric resistance to rapid motion being employed to counteract the
force of gravity.
The form represented in Fig. 2191 is that which illustrates the principle most clearly. On the crank-
shaft is fixed 11 drum or pulley o, and underneath it, or in any convenient situation, is placed an axis
carrying a small grooved pulley, to which are attached two or more fans or vanes PP. The former
communicates motion to the latter by means of an endless band or belt, which is also passed over two
friction-wheels, the first of which is attached to the weighted rod r, which commands the throttle valve
lever p, and the other to a gravitating weight q, suspended freely on the opposite side of the axis. The
area of the vanes PP, and the weight of the ball q, are 80 adjusted in relation to each other that the
latter is just sufficient to drive round the resisting vanes at a certain velocity, exactly corresponding
with the normal speed of the engine. Any increase of that speed, instead of accelerating the motion of
the vanes, (the atmospheric resistance being nearly uniform,) tends to raise the weight and diminish the
supply of steam passing through the steam-pipe N, and any relaxation of it allows the weight to de-
scend, and thereby opens the throttle-valve in a corresponding proportion.
1
2192.
2188.
x
a
D
at
2193.
N
2194.
2195
2196.
X
2195.
2197.
Figs. 2192 and 2193 are a side and end elevation of an arrangement in which this principle is carried
out in a more practical and more generally applicable form. It consists of an upright spindle 8 8, sup-
ported in suitable bearings in a cast-iron standard R, placed, in the usual manner, over the crank-shaft
Q of the engine, upon which is keyed a bevel-wheel, driving a pinion on the foot of the upright spindle,
whereby a rapid rotatory motion is given to it. The upper part of the spindle is formed into a screw
or worm, the threads of which slope at an angle of about 45°, and upon which a heavy bush or nut q is
fitted to move easily.
This bush, which is usually formed into a ball, and corresponds in its functions with the suspended
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GRAIN SEPARATORS.
weight q in the previous example, has attached to it two or more projecting arms furnished with vanes
PP; these are so fitted upon the arms as to be capable of being set nearer to or further from the
spindle, as circumstances may require; they also admit of being turned upon the arms in an oblique
direction, as shown by the dotted lines in Fig. 2193, in order to diminish the atmospheric resistance.
The weighted nut is connected to the throttle-valve by means of a double link and swivel K, and by
levers and rods M M, n n, in the usual manner.
From the above description it will be seen that when the spindle s is driven in the direction tending
to raise the nut q, the latter with its attached vanes will be carried round with it, and at the same velo-
city, until and so long as the resistance of the air against the vanes corresponds with the gravitating
power of the weighted nut. But when the velocity of the engine, and consequently that of the spindle 8,
is increased beyond that point, the atmospheric resistance against the vanes will exceed the gravitating
power of the nut and its mountings, and cause them to ascend upon the screwed spindle, and thus, by
means of the connecting-rods and levers K M, n p, will diminish the supply of steam passing through
the steam-pipe N to the engine. If, on the other hand, the velocity of the spindle is reduced below
that required by the resistance of the vanes to overcome the gravitating tendency of the nut q, the latter
will then descend upon the spindle, and thereby increase the passage for the supply of steam. The
speed of the engine may be permanently varied at pleasure, by adjusting the vanes upon their supporting
arms, 80 as to increase or diminish the gravitating power of the nut to the required extent.
The chronometric governor.-This is the name given to Figs. 2195 and 2196, by its inventor, Mr. C.
W. Siemens, of Berlin. The principle of its action appears to be an admirable and perfect one, involv-
ing as it does the happy idea of so combining the invariable motion of an independent pendulum with
the varying speed of the engine or other motor, as to make the former correct instantaneously the
fluctuations of the latter.
Fig. 2195 is an elevation, and Fig. 2196 a section of this apparatus, which is set upon a bracket SS
bolted to the wall of the engine-house, and supported by a frame-work TT, consisting of four small
columns and a circular entablature. The differential velocity between the engine and the revolving
pendulum Y is obtained by means of the three bevel-wheels t, u, and v; this last is firmly connected, by
an upright spindle and grooved arm w, with the upper extremity of the pendulum, produced through
the ball and socket joint, which forms its point of suspension and revolution. The under wheel t is fixed
to the pulley U, which is driven by the engine with its uncertain velocity, and in the contrary direction
to the motion of the wheel v. Both these wheels move in geer with the third bevel-wheel 26, which runs
perfectly free upon its axis, and is also permitted to travel round the perpendicular socket forming the
bearing of the others. It is obvious that if t and v revolve in contrary directions, but with equal velo-
cities, the wheel u will also revolve on its axis, but will not change its angular position; while any
difference in speed between t and v will cause the wheel u to follow the direction of the faster, which
will at once alter the supply of steam, the arm x being attached to the throttle-valve contained within
the steam-pipe N, by means of the lever and adjustable connecting-rod p and y. Another arm attached
to the axis of the wheel u, on the opposite side of the perpendicular socket, is connected by means of
the rod z to a lever working between two adjustable stops ZZ, which serve to confine the range of the
throttle-valve within convenient limits. To maintain the motion of the pendulum a constant power is
required, resembling that of the falling weight in an ordinary clock. This power is supplied by the
weight r, which tends constantly to pull the wheel u to one side; and this strain being borne equally
by the wheels t and v, causes the latter, and with it the pendulum Y, to revolve, while the former,
revolving in the contrary direction, is constantly engaged to raise the weight back again into its proper
position.
In practice it has been found that the power necessary for maintaining the action of the pendulum is
much less than that required to effect the movement of the valve; and accordingly Mr. Siemens has
adopted the principle of driving the pendulum with an excess of power, which shall be neutralized by
friction apparatus when not wanted, and shall be allowed to act freely when the governor requires its
assistance to move the valve. This is effected as follows: Surrounding the grooved arm w is situated
a conical ring W, cast with the framing TT, and accurately bored out; against the interior of this
"absorbing ring" a small piece of steel accurately fitted into the open end of the grooved arm w is
pressed by the short end of the pendulum rod X, a spring being interposed for the purpose of letting
the pressure come on gradually. It is evident that whenever there is an excess of driving weight
which causes divergence in the axis of rotation, the surface of the steel rubber and of the fixed ring will
be pressed together with a force exactly sufficient to balance the excess; and 80 soon as the pendulum
falls back towards a smaller arc of rotation it will relieve the friction apparatus, and permit an increased
supply of power to overcome the resistance of the valve. A second spiral spring is laid within the
grooved arm w, behind the point of the pendulum, for the purpose of preventing the latter from drop-
ping into its perpendicular position, and to facilitate its starting with the engine. The adjustment of
the valve is effected at the very instant that the equilibrium between the power and load is disturbed;
an advance of 1-50th of a revolution of the fly-wheel is found sufficient to close the valve entirely. By
converting the friction apparatus into a regular break, the power of the governor may be increased;
and in this way it may be applied for the regulation of water-wheels, and such steam-engines as are
furnished with variable expansion geer, which are better regulated by increasing or diminishing the
amount of expansion than by throttling the steam.
GRAIN SEPARATORS. This machine is an improvement on grain separators, invented by Ben-
jamin D. Sanders, of Hollyday's Cove, Va., and it is designed to separate the impurities in threshed
grain upon the reverse principle from the action of the common grain separators, or winnowing machines.
Instead of blowing or forcing by the blower, the chaff, &c., from the good grain, he forms a vacuum the
power of which can be regulated at will, to raise the chaff, and every thing specifically lighter than the
good grain up into a receiver or light grain-hopper, while the good grain is never raised off the screens,
but passes over them and falls into a granary below. A, is a frame to sustain the blower, which is
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GRAVITY, SPECIFIC.
909
confined in the cylinder C. B is the shaft to drive the blower by the drum below. D is an air-tight
trunk connected with the blower, and E a horizontal trunk, and F a perpendicular trunk, which is
placed above the receiving-hopper of the uncleaned
2198.
grain. G is the receptacle for the good clean grain.
J N is the place where the uncleaned grain is intro-
duced, the opening of which is regulated by a slide.
E
This uncleaned grain falls on to an inclined screen O.
The whole is air-tight above to the blower, which is
placed on the opposite end of the air-tight trunk, or
D
K
it may be termed trunks." There is no way for the
M
air to get in but under the screen 0, passing through
it, when the blower is in: motion. K is the hopper
into which falls the very light grain, or those impuri-
0
ties not lighter than the chaff. J is a slide to let them
1
out. L is a case through which the chaff is blown af-
И
ter being drawn down the trunk D, and through the
A
B
blower. M is a slide to regulate the power of the blow-
er. The trunk F is wider at the top than bottom, 80 as
c
to have a stronger current exerted upon the screw.
The blower being set in motion, a vacuum will be
formed in the trunk above; therefore a current of air will rush from below through the screen, carrying
up the stuff specially lighter than the good grain, the power of the blower being regulated for this pur-
pose. According as the impurities are forced to a distance above the centre of gravity, 80 is the power
to elevate them required to be greater. By this machine, the different qualities of grain and the im-
purities are separated, more distinctly upon the principle mentioned than by any other. The good
grain is deposited in a granary by itself, the very light in the hopper K, and the chaff completely
driven out of the machine.
GRAPHOMETER. Fig. 2199 represents this instrument as constructed by B. Pike, Jr., Broadway,
New York. The error arising from the use of an instrument, where the whole dependence is placed
on the needle, being frequently influenced by local attractions, has rendered it necessary for some other
method to be employed to measure angles with accuracy; among these, the common theodolite with
four sights has taken the lead. It is simple in its construction, and easy in its use.
Fig. 2199 represents the graph-
2199.
ometer, a brass plate or part of a
circle about twelve inches in diam-
eter, graduated on its edge from 0
to 180 degrees; in the opening be-
tween the moving centre and the
graduated arc, is a compass about
four inches in diameter; two sights
are fixed on the graduated arc, one
at 0 and the other at 180°. Per-
pendicular to the plane of the in-
strument, there is a movable limb
attached to the limb of the arc, but
a little shorter, and having the ex-
tremities slanted off, one of which
forms a nonius, subdividing the degrees on the limb to minutes, and having two sights, one at each end
in each sight there is a large and a small aperture, placed alternately, the large aperture in one sight
being always opposed to the narrow aperture in the other; underneath the plate is a spring to fit on
the pin of a ball and socket, which fixes it the single or three-legged staff, as may be required. In the
figure the ball and socket are represented detached from the instrument.
The four-sighted theodolite is the same instrument, except that the circle is entire, and the compass
is placed in the centre of the circle.
GRAVITY, centre of. The centre of gravity of any body or system of bodies is that point about
which the body or system, acted upon only by the force of gravity, will balance itself in all positions:
or it is a point which, when supported, the body or system will be supported, however it may be sit-
uated in other respects.
The centre of gravity of a body is not always within the body itself: thus the centre of gravity of a
ring is not in the substance of the ring, but in the axis of its circumscribing cylinder; and the centre of
gravity of a hollow staff, or of a bone, is not in the matter of which it is constituted, but somewhere in
its imaginary axis; every body, however, has a centre of gravity, and so has every system of bodies.
Varying the position of the body will not cause any change in the centre of gravity; since any such
mutation will be nothing more than changing the directions of the forces, without their ceasing to be
parallel; and if the forces do not continue the same, in consequence of the body being supposed at
different distances from the earth, still the forces upon all the moleculæ vary proportionally, and their
centre remains unchanged. See CENTRE OF GRAVITY.
GRAVITY AND GRAVITATION. These terms are often used synonymously, to denote the
mutual tendency which all bodies in nature have to approach each other. See FORCE, CENTRE OF
GRAVITY, and ATWOOD'S MACHINE.
GRAVITY, SPECIFIC. The specific gravity of a body is the ratio of its weight to an equal volume
of some other body assumed as a conventional standard. The standard usually adopted for solids and
liquids is rain, or distilled water, at a common temperature.
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910
GRAVITY, SPECIFIC.
In bodies of equal magnitudes the specific gravities are directly as the weights, or as their densities.
In bodies of the same specific gravities the weights will be as the magnitudes. In bodies of equal
weights the specific gravities are inversely as the magnitudes. The weights of different bodies are to
each other in the compound ratio of their magnitudes and specific gravities. Hence it is obvious that
of the magnitude, weight, and specific gravity of a body, any two of these being given, the third may
be found.
Ex. 1. The weight of a marble statue being 748 pounds avoirdupois, required the number of cubic
feet, &c., which it contains, the specific gravity of marble being 2.742. Since a cubic foot of marble
weighs 2742 ounces, we have, water being taken as 1000,
As 2742 : 748 X 16 : 1, 436 feet.
Ex. 2. Required the weight of a block of granite whose length is 63 feet, and breadth and thickness
each 12 feet, the specific gravity of granite being 2-625. Here 63 X 12 X 12 = 9072 feet then again,
As 1: 9072 2.625 : 23813900 ounces, or 664 tons 9 cwt.
A body immersed in a fluid will sink if its specific gravity be greater than that of the fluid if it be
less, the body will rise to the top, and be only partly immerged; and if the specific gravity of the body
and fluid be equal, it will remain at rest in any part of the fluid in which it may be placed. When a
body is heavier than a fluid it loses as much of its weight when immersed as is equal to a quantity of
the fluid of the same bulk or magnitude. If the specific gravity of the fluid be greater than that of the
body, then the quantity of fluid displaced by the part immerged is equal to the weight of the whole
body. And hence, as the specific gravity of the fluid is to that of the body, 80 is the whole magnitude
of the body to the part immerged. The specific gravities of equal solids are as their parts immerged
in the same fluid. The specific gravities of fluids are as the weights lost by the same immerged solid.
To find the specific gravity of a body.-This may be done generally by means of the hydrostatic
balance, which is contrived for the easy and exact determination of the weights of bodies, either in air
or when immersed in water or other fluid, from the
2200.
difference of which the specific gravity of both the solid
and fluid may be computed
D
B
d
1. When the body is heavier than water.-Weigh it
both out of water and in water; then say, as the
weight lost in water is to the whole or absolute weight,
so is the specific gravity of water to that of the body.
To do this, suspend the body by a hair to the short
arm of the hydrostatic steelyard represented in Fig.
2200. Then weigh it in the air, by sliding it on this
arm, until it balances any convenient weight hung at A;
the long arm being graduated into any convenient number of equal parts. Then immerse the body in
water, and weigh it by sliding the weight from A to C. Then as the division between A and C, is to
the whole number of divisions on A B, 80 is unity to the specific gravity of the body with reference to
the fluid in which it was immersed.
2. When the body is lighter than water.-In this case attach to it a piece of another body heavier than
water, so that the mass compounded of the two may sink together. Weig the denser body and the com-
pound body separately, both out of the water and in it; and find how much each loses in the water by
subtracting its weight in water from its weight in air; and subtract the less of these remainders from the
greater: then use this proportion, as the last remainder is to the weight of the light body in air, so is
the specific gravity of the water to the specific gravity of the body.
3. When the specific gravity of a fluid is required.-Take some body of known specific gravity;
weigh it both in and out of the fluid, and find the loss of weight in the fluid, by taking the difference of
these two; then say, as the whole or absolute weight is to the loss of weight, so is the specific gravity
of the solid to the specific gravity of the fluid.
By a fortunate coincidence it happens that a cubic foot of rain-water weighs 1000 avoirdupois ounces;
and, consequently, assuming this as the specific gravity of rain-water, and comparing all other bodies
with this, the same numbers that express the specific gravity of bodies will denote the weight of a cubic
foot of each in avoirdupois ounces.
Specific Gravities of different Bodies.
Metals.
Ounces.
Ounces.
Copper, not hammered
7788
Antimony, crude
4064
the same wire-drawn
8878
glass of
4946
ore of soft copper, or natural ver-
molten
6702
digris
3572
Arsenic, glass of, natural
3594
Gold, pure, of 24 carats, melted, but not
molten
5763
hammered
19258
native orpiment
5452
the same hammered
19362
Bismuth, molten
9828
Parisian standard, 22 car, not ham'd.
17486
native
9020
Iron, cast
7207
ore of, in plumes
4371
bar, either hardened or not
7788
Brass, cast, not hammered
8396
Steel, neither tempered nor hardened
7838
ditto, wire-drawn
8544
hardened, but not tempered
7840
cast, common
7824
tempered and hardened
7818
Cobalt molten
7812
ditto, not hardened
7816
blue, glass of
2441
Iron, ore prismatic
7355
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GRAVITY, SPECIFIC.
911
Ounces.
Ounces.
Iron, ore specular
5218
Pearl, virgin oriental
2684
ditto, lenticular
5012
Pebble, onyx
2664
Lead, molten
11352
stained
2587
ore of, cubic
7587
Prasium
2581
ditto, horned
6072
Sardonyx, pure
2603
ore of black-lead
6745
Schorl, octabedral
3226
ore of white-lead
4059
tourmalin of Ceylon
3054
ditto ditto vitreous
6558
antique basaltes
2923
Manganese striated
4756
Brazilian emerald
3156
Molybdena
4738
Stone, paving
2416
Mercury, solid or congealed
15632
cutlers'
2111
fluent
13568
grind
2143
precipitate, red
8399
mill
2484
brown cinnabar
10218
red cinnabar
6902
Various Stones, Earths, dc.
Nickel, molten
7807
Alabaster, oriental white
2780
ore of, called Kupfer-nickel of Saxe.
6648
ditto semi-transparent
2762
Platina, crude, in grains
15602
yellow
2699
purified, not hammered
19500
stained brown
2744
ditto hammered
20337
veined
2691
ditto wire-drawn
21042
Amber, yellow transparent
1078
ditto rolled
22069
Ambergris
926
Silver, virgin, 12 deniers, fine, not hammer'd.
10474
Amianthus, long
909
ditto, hammered
10511
short
2313
Tin, pure
7291
Asbestos, ripe
2578
ore of, red
6935
starry
3073
ore of, black
6901
Basaltes from Giants' Causeway
2864
ore of, white
6008
Bitumen of Judea.
1104
Tungsten
6066
Brick
2000
Uranium
6440
Chalk
2790
Wolfram
7119
Gypsum, opaque
2168
Zinc, molten
7191
semi-transparent
2306
Glass, green
2642
Precious Stones.
white
2892
Beryl, or aqua-marine oriental
3549
bottle
2733
ditto, occidental
2723
fluid
3329
Chrysolite of the jewellers
2782
Granite
2613 to 2956
of Brazil
2692
Hone, white razor
2876
Crystal, pure rock
2653
Lapis nephriticus
2894
Diamond
3530
Lazuli
3054
Brazilian
3444
Hæmatites
4360
Emerald of Peru
2775
Calaminaris
5000
Garnet
4063
Judaicus
2500
volcanic, 24 faces
2468
Manati
2270
Girasol
4000
Limestone
3179
Hyacinth, common
3687
Marble
2700
Jargon of Ceylon
4416
Obsidian stone
2348
Quartz
2624 to 8750
Peat, hard
1329
Ruby, oriental
4283
Phosphorus
1714
Brazilian
3531
Porcelaine, Sevres
2146
Sapphire, oriental
3994
China
2385
of Puys
4077
Porphyry
2750
Brazilian
3131
Pyrites, coppery
4954
Spar, white sparkling
2595
ferruginous cubic
3900
red ditto
2438
ditto, round
4101
green ditto
2704
ditto, of St. Domingo
8440
blue ditto
2698
Serpentine
2500
green and white ditto
3105
semi-transparent, fibrous
3000
adamantine
8873
Slate, common
2672
Topaz, oriental
4011
new
2854
pistachio ditto
4061
black-stone
2186
Brazilian
3586
flesh polished
2766
Vermilion
4230
Stalactite, transparent
2324
opaque
2478
Silicious Stones.
Stone, pumice
915
Agate
2620
prismatic basaltes
2722
Chalcedony, common
2616
touch
2415
Cornelian
2612
common
2520
Flint
2594
rag
2470
Jade, white
2950
rotten
1981
Jasper
2359 to 2816
hard paving
2460
Opal
2114
Sulphur, native
2033
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912
GRAVITY, SPECIFIC.
Ounces.
Ounces,
Sulphur, molten
1991
Wine, Bourdeaux
994
Talc, black crayon
2089
Madeira
1038
yellow
2655
Port
997
black
2900
Canary
1033
white
2704
Liquors, Oils, dc.
Resins, Gums, Animal Substances, &c.
1841
Aloes, socotrine
1380
Acid, sulphuric
hepatic
1359
ditto, highly concentrated
2125
nitric
Asafœtida
1328
1271
Bees-wax, yellow
965
ditto, highly concentrated
1580
white
969
muriatic
1194
Bone of an ox
1656
red, acetous
1025
Butter
942
white, acetous
1014
distilled ditto
Calculus humanus
1700
1010
fluoric
ditto
1240
1500
acetic
ditto
1434
1063
1558
Camphor
989
phosphoric
formic
994
Copal, opaque
1149
Madagascar
1060
Alcohol, commercial
837
Chinese
1063
highly rectified
829
Crassamentum, human blood
1126
mixed with water,
Dragon's blood
1205
15-16ths alcohol
853
"
Elemi
1018
14-16ths
867
13-16ths
"
882
Fat, beef
923
"
Galbanum
1212
12-16ths
895
"
Gamboge
1222
11-16ths
908
10-16ths
"
Gum, ammoniac
1207
920
Arabic
1452
9-16ths
"
932
Euphorbia
1124
8-16ths
"
943
"
seraphic
1201
7-16ths
952
6-16ths
"
960
tragacanth
1316
"
bdellium
1372
5-16ths
967
"
973
Scammony of Smyrna
1274
4-16ths
3-16ths
"
979
Gunpowder, shaken
933
836
2-16ths
"
985
in a loose heap
"
solid
1745
1-16th
992
897
Honey
1450
Ammoniac, liquid
Beer, pale
1023
Indigo
769
brown
1034
Ivory
1826
Cider
Juice of liquorice
1723
1018
of Acacia
1515
Ether, sulphuric
739
nitric
Labdanum
1186
909
muriatic
Lard
948
730
acetic
Mastic
1074
866
Myrrh
1360
Milk, woman's
1020
cow's
Opium
1336
1032
Serum of human blood
1030
ass's
1036
ewe's
1041
Spermaceti
943
goat's
Storax
1110
1035
Tallow
942
mare's
1034
cow's clarified
1019
Terra Japonica
1398
Oil, essential, of turpentine
870
Wax, shoemakers'
897
ditto, of lavender
894
ditto, of cloves
Woods.
1036
ditto, of cinnamon
1044
Alder
800
of olives
915
Apple-tree
793
of sweet almonds
917
Ash, the trunk
845
of filberts
916
Bay-tree
822
linseed
940
Beech
852
of walnuts
923
Box, French
912
of whale
923
Dutch
1328
of hempseed
926
Brazilian red
1031
of poppies
924
Cedar, wild
596
rapeseed
919
Palestine
613
Turpentine, liquid
991
Indian
1315
Urine, human
1011
American
561
Water, rain
1000
Citron
726
distilled
1000
Cocoa-wood
1040
sea (average)
1026
Cherry-tree
715
of Dead Sea
1240
Cork
240
Wine, Burgundy
992
Cypress, Spanish
644
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GRINDING MACHINE.
913
Ounces.
Ounces.
Ebony, American
1331
Medlar
944
Indian
1209
Mulberry, Spanish
897
Elder-tree
695
Oak, heart of, 60 years old
1170
Elm, trunk of
671
Olive-tree
927
Filbert-tree
600
Orange-tree
705
Fir, male
550
Pear-tree
661
female
498
Pomegranate-tree
1354
Hazel
600
Poplar
383
Jasmine, Spanish
770
white Spanish
529
Juniper-tree
556
Plum-tree
785
Lemon-tree
708
Quince-tree
705
Lignum-vitæ
1833
Sassafras
482
Linden-tree
604
Vine
1327
Logwood
913
Walnut
671
Mastick-tree
849
Willow
585
Mahogany
1063
Yew, Dutch
788
Maple
750
Spanish
807
Weight and Specific Gravity of different Gases.
Fahrenheit's Thermometer 55°. Barometer 30 inches.
Specific Gravity.
Wt. Cub. Foot.
Atmospheric air
1.2
5250 grains.
Hydrogen gas
01
43.75
Oxygen gas
1.435
627812
Azotic gas
1.182
517125
Nitrous gas
1-4544
636383
Ammoniac gas
7311
319832
Sulphureous acid gas
2-7611
1207978
In this table the weights and specific gravities of the principal gases are given, as they correspond
to a state of the barometer and thermometer which may be chosen for a medium. The specific gravity
of any one gas to that of another will not exactly conform to the same ratio under different degrees of
heat and other pressures of the atmosphere.
And if common air, the standard, be taken at unity (1), chlorine oxymuriatic acid will be 2.500, and
hydrogen 0.069 whence we conclude that chlorine is 21 times heavier than hydrogen, and this last is
14 times lighter than common air. For, to arrive at the absolute weight of the gases, we have only to
assume 100 cubic inches of atmospheric air to weigh 30.5 grains, and as there are 1728 cubical inches
in a cubic foot, the simple proportion
100 : 30-5 grains : : 1728 : 527-04 grains,
the weight of a cubic foot of common air.
And for any other gas, it is only necessary to observe its specific gravity in relation to that of common
air; for example, chlorine has a specific gravity of 25; hence a cubic foot of chlorine will weigh 21
times as much as a cubic foot of common air; for
52704 X 21 = 13176 grains,
the weight of a cubic foot of chlorine.
To determine the weight of any gas lighter than common air, we also compare their specific gravities
thus, the specific gravity of ammoniacal gas is 0-5, and that of atmospheric air being = 1, we have
1 : 0.5 : 1728 : 8640, or simply 1728 ÷ 2 = 864 grains, for the weight of a cubic foot of ammoniacal
gas; and so on for all the other gaseous bodies, as they are arranged in the following table.
If atmospheric air be taken at unity (1), then the various gases will stand as under :-
Atmospheric air
1-000
Hydrogen
0.69
Ammoniacal gas
0.500
Muriatic acid
1.284
Carbonic acid
1527
Nitric oxide
1041
Carbonic oxide
0.972
Nitrogen
0.972
Carburetted hydrogen
0972
Nitrous acid
2-688
Chlorine
2.500
Nitrous oxide
1527
Chlorocarbonous acid
3-472
Oxygen
10111
Ohloroprussic acid
2.152
Phosphuretted hydrogen
0-902
Cyanogen
1805
Prussic acid
0.987
Euchlorine
2·440
Subcarburetted hydrogen
0-555
Fluoboric acid
2871
Subphosphuretted ditto
0972
Fluosilicic acid
3632
Sulphuretted ditto
1.180
Hydriodic acid
4846
Sulphureous acid
2222
GRINDING MACHINE, double. By Messrs. Nasmyth, Gaskell and Co. The object of the machine
represented by Figs. 2201, 2202, and 2203, is to grind up the faces of the different parts of machinery,
when a great surface is required to be made perfectly smooth; to accomplish which, this contrivance
has been used.
Figs. 2201, 2202, and 2203, severally show a side elevation, an end elevation, and a plan of a double-
face grinding machine, the one side being a repetition of the other. To the two cast-iron cross-frames a an
115
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914
GRINDING MACHINE.
are bolted two large plummer-blocks for carrying the main shaft, having at each extremity the circular
frames divided into twelve compartments, in which are placed the grinding stones f, each being adjust-
able by the small set screws m round its circumference. On the top of the cross-frames a, are placed
two longitudinal frames bb, made also of cast-iron, for supporting the long bed-frames cc, and also the
self-acting apparatus furnished to this machine. Two motions, the one at right angles to the other, are
given by the alides d working along the beds c, and also the face-plates e for carrying the work, by
which it is brought into contact with the grinding stones. Pits are made to allow the wheels, for car-
rying the stones, to work in.
2201.
BR
HP
&
MAY
7
c
Я
6
f
b
a
976
&
B
The self-acting motion given to the work being faced, by means of which it slides along the bed c
while the grinding stones are revolving on their axes, is thus obtained: on the main shaft next to the
driving-riggers or pulleys g, is a worm l, which, as it revolves, works a worm-wheel represented by the
dotted lines in Fig. 2202, thus communicating the motion to the upright spindle from this it is carried
by the bevel-wheels to the spindle running horizontally the whole length of the machine, having at
each extremity three small bevel-wheels. The action of this apparatus is thus, supposing the slide to
be travelling in the direction towards the small bevel-wheels, two of which are required for the pur-
pose, while the third or outer one runs freely on the spindle, without producing any effect, the small
2202.
8
R
h
2
m
b
I
b
a
a
8
clutch being disengaged from it; on the travelling slide d is fixed a stud or pin h'; a long rod h of the
same length as the bed c, is movable in two stud-bearings fixed to it. As the slide d travels, the pin h'
comes into contact with a second stud or pin adjusted to any position on the rod h, according to the
length of the motion required, which must naturally press it forward, and thereby throw out the clutch
on the end of the spindle, which being shifted from one bevel-wheel to the other, disengages that which
had been at work before, while it engages the outer one, that had been running loosely on the spindle;
by this curious contrivance, the screw for working the slide revolves in a contrary direction, and instead
of drawing the slide d towards it, sends it back. A counterbalance weight n is connected to the ex-
tremity of the rod h, for keeping it in a steady position while this operation is being performed.
The tappet-wheel k, fixed on the end of the screw for advancing the other slide e, is also worked by
a pin on the same rod h, whereby the work is advanced to the face of the grinding stone; it is on the
upper part of the slide e that the work is fixed. A substantial foundation, consisting of stone-work, is
prepared for receiving the two frames aa, and to which they are firmly bolted down by strong hold-
ing-bolts.
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GRINDING MILL.
915
Another mode of performing this same operation might be adopted, by fastening a whole grindstone
into the chucks, and passing a bolt through two surface plates of two feet diameter each, one on the
middle part of each face of the grindstone, by which means they would be more effectually secured in
their places.
2203.
i
13
b
of
to
c
m
A
a
a
h
e
€
9
e
.
.
References to Figs. 2201, 2202, and 2203.
a, cross-frames or standards.
m Rods for reversing motion by means of tappet A' and
b, Longitudinal frames.
i, Clutches.
[clutches d.
c, Bed-plates.
j, Bevel-wheels for working slides.
d, Cross-slides.
k, Tappet-wheels.
a Slides or face-plates for carrying work.
1, Worm on main shaft for working bevel-geer j.
f, Grindstones.
m. Screws for setting stones.
8, Driving-riggers.
m, Counterbalance weights.
GRINDING MILL, Bogardus' Eccentric. This is a machine the invention of which is due to Mr.
Bogardus, of New York. The following are some of the advantages of mills worked on this principle:-
1. The peculiar motion of the plates will, of itself. discharge the ground substance, so that many sub-
stances can be ground thereby which would altogether choke other mills.
2. In other mills, argiven point in one of the plates continually describes the same circle on the
other; but in this milkst traverses on the other plate at an infinite variety of angles, every point within
two concentric circles apart from each other, twice the distance of the centres of the plates, thereby
rendering the wear and tear of the plates uniform, and preserving the grinding action of every point.
3. In other mills, the grinding power of each point increases with its distance from the centre; but
in this mill, every point from the centre to the circumference has the same grinding power. A con-
siderably smaller mill will, therefore, effect a given purpose, and the eccentric mill is therefore more
portable than other mills.
4. The ever-changing action of the mill, and the quick discharge of the substance ground, prevent it
from becoming heated, so that the eccentric mill may be profitably employed in grinding substances
which, in other mills, would be either spoiled or deteriorated in quality-or, by their melting, be im-
possible to be ground. If other mills were driven with that speed which can be safely applied to the
eccentric mill, they would be made red-hot in a few minutes.
These mills have been successfully introduced for the following purposes:-Hulling rice, coffee, and
olives. Grinding grain of all kinds; paints of all kinds, in water or in oil; iron, zinc, copper, and gold
ores, plumbago and manganese, bones for manure, and bones for refining sugar, flint and quartz, char-
coal, plaster, putty, printers' inks, drugs and dye-stuffs, snuffs, mustard, coffee, spices, loaf sugar, starch,
gums, resins, asphaltum, India-rubber, flax-seed, and oil-cake, &c., &c.
Of the substances enumerated, some cannot be ground at all by other mills; in short, the eccentric
mills are more economical in the power required to drive them, and in the labor of tending them; they
are less costly for the work they do, and more portable; they are capable of being applied to purposes
for which other mills are useless; and the tear and wear is trifling.
The mill should run to the right, and make not less than three hundred revolutions per minute.
Nearly any quantity can be ground by increasing the speed. The mill is regulated to grind fine and
coarse by the under-screw, on which the end of the shaft revolves; turning the screw to the left, will
bring the plates together and cause the mill to grind finer. The regulating screw is held firmly in any posi-
tion by a small screw placed against its side. There are three reservoirs, which should be well supplied
with oil. The first is on the top of the upper plate: two or three table-spoonfuls of oil should be poured
into this reservoir through a small hole made in the top of the mill for that purpose. The second res-
ervoir is the box, through which the man shaft passes; this is just under the spout of the mill. This
reservoir should be filled with tallow so that it may supply itself. There is also a small hole in the
back part of the mill, through which oil can be poured into this reservoir, if requisite. The third reser-
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916
GRINDSTONES.
voir is the step in which the main shaft revolves, that may be filled with oil. The feeding is regulated
by a shoe acting against the tube of the upper plate, which causes the shoe to vibrate; this, with the
slide in the hopper, regulates the quantity fed into the mill. Screw holes are made round the rim of
the hopper, for the purpose of extending its size to any dimensions required. The mill can be taken
apart, cleaned, and the plates changed (if necessary) in a few minutes.
Fig. 2204 represents a front elevation of one of the mills applied by Mr. Bogardus to the grinding of
moist or liquid substances.
2204.
U
0
A is an upright cast-iron frame, carrying three projecting brackets, as seen at B. The upper revolv-
ing plate is seen at C; it is driven by the pulley D; beneath this plate is placed the lower separate re-
volving plate, at a distance from it to suit the nature of the material to be ground. The centre of mo-
tion of the latter plate is placed about an inch out of the centre of the upper one; it is driven merely
by friction generated by the abrasion of the substance in process of grinding between the plates. An
adjusting screw F is placed beneath the lower plate for the purpose of setting the latter at the proper
distance from the upper plate.
GRINDSTONES. A well-known tool, used in nearly all branches of the mechanic arts for grind-
ing to an edge, point, or face the various tools used in manufacturing, and also in various hardware
manufactories for reducing metallic surfaces.
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GRIST-MILL.
917
Grindstones vary in size according to the purpose for which they are intended. In grinding to a
smooth surface large saws, axes, scythes, swords, and all heavy cutlery, heavy stones are used, weighing
sometimes from two to three tons; these are secured on wrought-iron shafts, and the workman applies
his weight to the article on the stone.
Grindstones are brought to this country from France and England, and they are obtained in Nova
Scotia, Ohio, and elsewhere in this country in small quantities. The sandstone from which they are
almost entirely composed is split out of the quarry by wedges, and dressed on the sides by chisel
and hammer. Many of these require no side dressing. A square hole, in proportion to the weight, is
cut in the centre, and the stone marked from this centre; the face is then chipped down, as near as may
be, to its intended circumference, and sent to market. After mounting and wedging the stone upon its
axle, it is chipped off at the prominent points and then rough-turned. The heavy stones in particular
requiring great care in the hanging and trimming, that they may run smoothly.
GRIST-MILL, Barber's Patent Metallic. This is the invention of Mr. Asa Barber, and patented in
June, 1847. The mill is capable of grinding corn in the ear, and can also grind all other kinds of grain;
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and although it has metal grinders, never requiring to be sharpened, it is 80 constructed and the cooling
surfaces so arranged that the grain is not heated. By a two-horse power it it capable of grinding from
eight to ten bushels per hour.
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Description. A is the frame. B is the hopper. C are stays connected with the longitudinal
beam of the frame supporting the hopper. E is a large revolving cylinder, covered with a wire cloth
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for bolting. F is a fly-wheel. G is a band-wheel or pulley, driven by a band from the main driver to
propel the shaft H, which has a small pinion on it meshing into cogs or a large cog rim I of the large
cylinder E. J is a small pulley on H, which drives by a band the shaft (not seen) of an interior
scraper. K K are two angular boards, to guide the ground meal into the granary.
This is a sectional view, and does not show all the interior, but merely the grinding surfaces. B is
a revolving iron grooved roller, made of a series of cast grooved rings secured to the shaft. This shaft
is made to sit and revolve in 0, a concave iron grooved bed which is stationary. D is a shoulder with
teeth to grind the cob as it leaves the hopper before being submitted to the grinding operation of the
revolving roller B. Suppose these two sections to be placed in the inside of E, with B revolving above
and in the concave bed O. Now the grain enters in the hopper, and the revolving roller being set in mo-
tion, it will easily be perceived that the grain will be carried into and between the roller and the bed, and
discharged through the channels or grooves on C. Still the meal thus ground has to be bolted. This is
done in a most simple manner. As E is revolved the fine meal falls through the bolting-cloth at the
bottom, and the coarse is carried round and falls down into the mill above, to be ground over again
By this way of grinding the revolving grinder and the bed need not be in such close contact as other
grinding mills must be, and the large revolving surface of E keeps the meal perfectly cool and allows
the interior of the mill to be quite open to the atmosphere. There is a scraper which is revolved by
the band from I, at the right of Fig. 2205, which scraper keeps the grooves of the roller or bed from
getting clogged.
GUAGE, STEAM. An instrument for showing the pressure of steam or other fluids. For a full
description of Stillman's guages, see article MANOMETER.
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GUAGE. Steam and Water-safety Guage, for Steam-boilers, patented by A. S. LYMAN. Two of
these guages are exhibited in Fig. 2207, which, though very similar in construction and principle, are
intended for very different purposes-the one to indicate the pressure of the steam, and the other as a
water-guage, giving alarm when the water falls below the proper level. In these guages, which act
by the condensation of air in a glass tube, it is well known, as ordinarily constructed, that the divisions
on the scale are all dissimilar, by reason of the glass tube being parallel throughout. To indicate one
atmosphere, the air is forced into one-half the length of the tube, the mercury rising a corresponding
distance; the next atmosphere being indicated by one-half the preceding rise of the mercury. By
constructing the glass tubes E and F, of a form as shown in the figure, the divisions on the scale
may be brought to approximate equal distances. The bulbs E and F are nearly filled with colored
alcohol, which prevents the mercury from rising above 0 in the scale, and by its oxide defacing the
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inner surface of the glass. The guage F is that for indicating the steam pressure, and is connected
by the pipe h with the steam space in the boiler. This terminates in a chamber L, from which a
pipe G depends, communicating with the mercury cup I of the guage. This pipe always contains
a column of water, which remains cold, and prevents the communication of heat to the guage, to
avoid its fracture from sudden expansion, as is frequently the case in ordinary guages. The cham-
ber L has also a valve, in which, when the pressure of steam in the boiler becomes excessive, or
above a certain point, it will blow off through a steam-whistle. The other guage E, instead of
communicating with the water space, is connected by the pipe C with a steam-tight box S. filled
with water and placed above the flue B of the boiler A. A column of water in the pipe D also
intervenes between the steam and the mercury in the cup K. The connecting chamber o has a siphon
pipe P, filled with water, which is pressed upwards by the steam against a flexible diaphragm Q of
vulcanized India-rubber, or other suitable material. On this diaphragm a plunger I, with an area six
or eight times larger than that of the valve M, rests, and according to the pressure of the steam will exert
more or less upward force on the lever R, and when in excess it will exert a force on the lever M, and
assist in raising that lever, should it accidentally adhere to its seat, thereby preventing the possibility
of an accident from such cause, the lever R being unerring in its action, by the means described. It is
well known that when the water falls too low in the boiler, the steam is sometimes heated 80 as to
melt common solder in the steam-pipe; that is, to 475°, but not being saturated with water, it presses
no higher than ordinarily. This box S, supplied with water and immersed in such steam, would com-
press the air in the water-guage indicator E with a force of over five hundred pounds per inch, as the
water or steam in this box and its guage cannot escape. But as soon as the point considered as the
limit of safety is reached, whether caused by low water or high pressure of steam, the pressure of the
water on the diaphragm Q raises the valve M, as stated, and gives the alarm. The pipes containing
the cold water columns G, D, and P are lined with a thick coating of India-rubber, in order to prevent
the pipe bursting from expansion by frost. A thermometer U is appended to these guages for refer-
ence in subtracting from, or adding to, the indicated pressure, to compensate for the expansion and
contraction at the different degrees of heat, 72° temperature being assumed as zero, from which, for every
eight degrees below that temperature, one pound is deduced, as exhibited by the sign minus," and
vice versd, a like addition is made, as shown by the sign "plus," by which the true degree of pressure in
the boiler is obtained.
GUAGE, TELEGRAPHIC STEAM-Dun's. Fig. 2208 represents so much of a steam-boiler as is
necessary for our description. A tube descends into the boiler just below the proper water-line, and
is secured to the sides. The branch C is fixed to the upper end, into which two tubes, B and N, are fixed.
The tubes and the branch C are filled with mercury to a fixed level at the proper temperature of the
boiler. In the tube N is a wire set in such a manner that its lower end, which should be of platina,
will come just above the quicksilver in the tube when it stands at the height which will be caused by
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the heat which should produce the pressure of steam desired in the boiler, and at starting, the appara-
tus is to be adjusted when the steam is at the working pressure in the boiler; and when the wire is so
adjusted it is fixed by the set-screw O. From the upper end of the wire in the tube N, proceeds the
wire to the bell apparatus PQ for the engineer, and at RS in the office; thence the wire proceeds to
the battery A L. By this arrangement. when the heat in the boiler rises above that which is proper for
producing the desired pressure of steam in the boiler, the quicksilver expands, and coming in contact
with the platina wire, completes the electric circuit, and the bells will continue to ring. If desired, the
tube N may have a graduated scale to indicate the temperature at sight.
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GUDGEON. The extremity of a horizontal shaft of a water-wheel, that runs in the collar. Every
gudgeon, in order to avoid unnecessary friction, should be made as small in diameter as possible, con-
sistently with the requisite strength and durability. The cube root of the weight of a water-wheel in
hundred weights, is nearly equal to the diameter in inches of a cast-iron gudgeon sufficiently strong to
support such wheel. For wooden water-wheels, multiply the diameter in feet by the width also in feet,
to which add the square of half the diameter; the cube root of the sum will be nearly equal to the
diameter of the gudgeon in inches. It has been inferred from experiment that gudgeons of the same
size, of cast and of wrought iron, are capable, at a medium, of sustaining weights without flexure, in
the proportion of 9 to 14. See GEERING, page 841.
GUNS. Every best finished gun usually passes through fifteen or sixteen hands, each of which con-
stitutes almost a distinct trade; although two or three branches are often combined, or subdivided,
according to the extent of business. They may be arranged in the following order:-
1. Barrel forger; 2. lock and furniture forger; 3. barrel borer and filer; 4. lock filer; 5. furniture
filer; 6. ribber and breecher; 7. stocker 8. screwer-together; 9. detonator; 10. stripper and finisher;
11. lock finisher; 12. polisher and hardener; 13. engraver; 14. browner; 15. stock polisher. The
barrel-making being also divided into several branches.
The first process in the manufacture of musket or common barrels is the making what are techni-
cally called skelps. The skelp is a piece of iron about one foot long, but thicker and broader at one
end than at the other; and the barrel of a musket is formed by forging out such pieces to the proper
dimensions, and then folding or bending them round into a cylindrical form until the edges overlap, so
that they can be welded together. It is then placed in a furnace, raised to a welding heat, and taken
out, when a triblet or cylinder of iron being placed in it, it is passed quickly through a pair of rollers.
The effect of this is, that the welding is performed at a single heating, and the remainder of the elonga-
tion necessary for bringing it to the length of a musket-barrel is performed in a similar manner, but at
a lower temperature. This method of welding is far less injurious to the texture of the iron, which is
now exposed only once, instead of three or four times to the welding heat.
The barrels for fowling-pieces are of various kinds, as stub, stub-twist, wire-twist, and Damascus-twist,
and sometimes a combination of the two latter ones, as well as another description called stub-Damas-
cus. These are the best varieties, but a number of inferior kinds are made, which are only employed
for very common guns.
In order to make stub-iron, old horse-shoe nails, called stubs, are collected, then packed closely to-
gether, and bound with an iron hoop, so as to form a ball about ten or twelve inches in circumference
which, being put into a furnace or forge-fire, and raised to a welding heat, is united by hammering, and
drawn out into bars of convenient lengths, for the purposes intended. This method is adopted for the
locks, furniture, and breechings of all best guns, and is to a certain extent practised for barrels, though
not so much as formerly, more expeditious methods being employed on a las ge scale.
The most approved modern method of converting them into gun-barrels, (after carefully sorting and
picking them, to see that no cast-iron or impurities are mixed with them,) is first to put about half a
hundred weight into a large cast-iron drum or cylinder, crossed internally with iron bars, through the
centre of which a shaft passes, which is connected by a strap with the steam-engine, and the revolution
of the drum actually polishes the nails by their friction against each other; they are then sifted, by
which every particle of dust is removed. The steel intended to be mixed with them is clipped by
means of large shears, worked by the engine into small pieces, corresponding in size to the stubs, and
afterwards cleansed by a similar process. About 40 lbs. are thrown on to the inclined hearth of an
air-furnace, where they are puddled or mixed together with a long iron rod, and withdrawn in a mass
called a bloom, almost in a state of fusion, to be welded under a hammer of three tons weight, by which
it is formed into a long square block: this being put in, at another door of the same air-furnace, is raised
to a bright red-heat, and drawn out under a tilt-hammer of a ton and a half weight, into bars of a
proper size to pass the rollers, by means of which it is reduced to rods of the required size. The air-
furnace having two doors prevents any loss of time, as the moment one ball of stubs is withdrawn,
another charge is put in, and the two operations go on together, keeping both hammers employed.
The iron thus produced is very tough, and free from specks or grays, but stubs are hardly ever used
alone, as they were formerly, being too soft therefore, a portion of steel is mixed with them, which
varies from one-eighth to one-half of the whole mass. It need hardly be remarked, that the advantage
to be derived from the use of horse-shoe nails does not arise from any virtue in the horse's hoof, as some
have imagined, but simply because good iron is, or ought to be, originally employed for the purpose,
otherwise the nails will not drive into the hoof; and the iron, being worked much more, is freed from
its impurities, which can only be effected by repeated workings.
When gun-barrels are manufactured from stub-iron by a process similar to that of musket-barrels,
they merely exhibit a mottled appearance on the application of acids. It is also usual to make what
are called stub barrels from scrap iron cut into small pieces by means of shears worked by the engine.
It would be difficult to define what scrap iron is, or what it is not, being composed of every thing in
iron that has previously been manufactured, as well as of the cuttings from the various manufactories;
these are sorted and employed in preparing iron of various qualities, known by the names of wire-twist,
Damascus-twist, stub-twist, charcoal iron, threepenny skelp iron, twopenny skelp, &c.
The object of preparing iron from small pieces, is to cross and interweave the fibres in every possible
direction, and thus greatly to increase its tenacity. Very few plain stub barrels are now made, as iron
of inferior quality, when twisted, finds a more ready sale. For the finest description of barrels, a cer-
tain proportion of scrap steel, such as broken coach-springs, is cut into pieces and mixed with the iron
by the operation called puddling, by which the steel loses a considerable portion of its carbon, and be-
comes converted into mild steel, uniting readily with the iron, and greatly increasing the variegation
and beauty of the twist. In whatever manner the iron may be prepared, the operation of drawing it
out into ribands for twisting is the same. This is effected by passing the bars, while red-hot, between
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rollers until extended several yards in length, about half an inch wide, and varying in thickness accord-
ing to whichever part of the barrel it may be intended to form: these ribands are cut into convenient
lengths, each being sufficient to form one-third of a barrel one of these pieces is made red-hot and
twisted into a spiral form, by placing one end in the prong of an iron rod, which passes through a frame,
and is turn 1 by a handle, the riband being prevented from going round without twisting by means
of an iron ba. placed parallel to the revolving rod. The spiral thus formed is raised to a welding heat,
and dropped on to a cylindrical iron rod, which being struck forcibly on the ground, (jumped,) the edges
of the spiral unite, and the welding is then completed by hammering on the anvil: the other spirals
are added according to the length of the barrel, and the forging is finished by hammering regularly all
over. The ends of each spiral should be turned up and united at each junction of the spirals, to avoid
the confusion in the twist occasioned by merely dropping one spiral on another; but this is rarely done.
Wire-twist, of any degree of fineness, may be obtained by welding alternate laminæ of iron and steel,
or iron of two qualities, together; the compound bar thus formed is drawn into ribands, and twisted in
the same manner as the preceding. The operation of twisting the iron not only increases the beauty of
the barrel, but adds considerably to its strength by opposing the longitudinal direction of the fibres to
the expansion that takes place in the act of firing. The iron called Damascus, from its resemblance to
the celebrated Oriental barrels and sword-blades, is now manufactured by welding 25 bars of iron and
mild steel alternately, each about 2 feet long, 2 inches wide, and 1 of an inch thick; and having drawn
the whole mass into a long bar, or rod, 1 of an inch square, it is then cut into proper lengths of from
five to six feet; one of these pieces being made red-hot, is held firmly in a vice, or in a square hole, to
prevent it from turning, while the other end is twisted by a brace, or by machinery, taking care that the
turns are regular, and holding those parts which turn closer than others with a pair of tongs; the rod
is by this means shortened to half its original length, and made quite round. If only two pieces are
employed to form the riband, one is turned to the right, and the other to the left; these being laid
parallel to each other, are united by welding, and then flattened; but if three square rods are used, the
centre one is turned in a contrary direction to the outside ones, and this produces the handsomest
figure. By these operations the alternations of iron and stecl change places at every half revolution of
the square rod composed of twenty-five laminæ; the external layers winding round the interior ones,
thus forming, when flattened into a riband, irregular concentric ovals or circles. The fineness of the
Damascus depends on the number and thickness of the alternations; and the figure of the riband
when brought out by acids resembles that of a curled ostrich feather; but when wound into a spiral
form, and united on its edges by jumping, the edges bend round and the figure is completed. This is
sometimes veneered on common iron; and they often wind a thin riband of Damascus, or superior
iron, round iron of the worst quality; even gas tubing is considered good enough, when coated in this
manner, to form gun-barrels of a very low price with a high-priced appearance. Stub Damascus is
merely one square rod of Damascus iron twisted and flattened into the riband for forming the
barrel.
Damascus and wire-twist is a riband of each, twisted together to make a greater variety but there
is no quality so good as the best regular stub-twist. The Swedish iron, known by the mark CCND,
and coach-springs, form an excellent combination for Damascus barrels. The next operation to forging
is rough boring this is usually performed by machinery. A long square bit, attached to a rod, revolves
with great rapidity, while the barrel is pressed forward by a crooked lever, one end of which the work-
man holds, and passes the other end along a series of nails or pegs, driven into the top edge of the
trough or bench, on which the barrel is placed, thus forcing the barrel forward along the boring-bit.
Water is kept constantly flowing over the barrel during the process, otherwise the heat generated by
the friction would soon soften the bit, and render it useless. The outsides are then ground on very
broad stones turned by the engine; the workman site on a kind of wooden horse, firmly chained to the
floor; a sloping board, nearly in contact with the grindstone, is placed before him, against which he
leans, and rests the barrel; a long iron rod passes through the barrel, and projects at each end, suffi-
ciently to form handles, and at the same time an axis, on which the barrel rotates more or less freely,
according to the degree of pressure against the board. By moving it regularly sideways, the whole
surface is ground over. It is evidently impossible to finish barrels with any great accuracy on a grind-
stone, though most of the barrels that are made into guns in Birmingham are merely smoothed up after
this process-an appearance of regularity being given to them at the muzzle by filing; but if trans-
verse sections were made at different distances, they would be found very unequal in substance, as is
always the case with musket and other common barrels, although some of the grinders are able to
finish with considerable accuracy. It is in the ground and rough-bored state that most of the best bar-
rels are sent to the finishing gun-smith, where, after being set perfectly straight, they are fixed on a
movable carriage, which is drawn gradually forward along a level surface or railway, by means of a
weight and pulleys; the boring-bit being fixed in a square hole in the axis of a fly-wheel which is
turned by hand or by steam machinery, while the barrel slowly advances until the bit passes out at
the opposite end to that at which it entered. The same square bit is made to enlarge the bore to the
required size by the addition of a spill, which is simply a long thin piece of wood slightly taper, flat on
one side and round on the other this being placed along one side of the bit, causes it to cut on two
angles only, and the size of the caliber may be very gradually increased by the interposition of strips
of writing-paper between the spill and the bit. After the barrel is correctly bored, the external part is
turned in a lathe; a steel mandril being introduced at each end. The barrel is thus rendered perfectly
correct and equal in every part. The barrel being tapped that is, screwed at the breech end, and the
plug fitted, is now proved with a charge of powder proportioned to the weight of a leaden ball that fits
the bore; this is always five or six times the ordinary load; besides which, it is forced with water, as
minute defects, invisible to the eye and not affected by the proving, are thus easily detected. When
false-breeched, ribbed, stocked, and screwed together, the barrel is bored for shootin 1, and smoothed out-
side. Double barrels have a flat struck along the inner side of each, previous to laying them together;
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about four inches of the breech end is brazed, or hard soldered, and the remainder of the length soft
soldered; the upper and under ribs being soldered on at the same time.
The progressive stages of best gun-making may be briefly enumerated in the following order, sup-
posing the lock and barrel to be already made. The lock and barrel being jointed to each other, (if the
plan require it,) are given to the stocker, who lets them into the wood, which ought to have been pre-
viously cut out of the plank at least two or three years, in order to be perfectly seasoned. The next work-
man is the screwer-together, who lets in all the furniture and puts in all the screws: when this is done,
the gun is detonated by another workman who fits the cock, and finishes the external part of the
breeching. The barrel then goes to the barrel-maker to smooth and bore for shooting, and the gun is
returned to the screwer-together. From him it passes to the stripper and finisher, who takes the whole
to pieces and corrects any trifling errors of preceding workmen. The barrel is engraved, browned; an
operation performed by producing successive coatings of rust on the surface, and brushing them off as
they arise with a fine steel wire scratch-brush, until the required color be obtained, which usually takes
a week, and is effected by a solution of metallic salts, combined with nitric ether; during this process
the lock and furniture are polished, engraved, blued, and hardened, and the stock is oiled and polished.
The hardening is performed by stratifying the various parts in an iron pan, with animal charcoal, pre-
pared from bone and ivory-dust, or old shoes the whole is then exposed to a full red-heat for about an
hour, or according to the size of the work, the pan is withdrawn from the fire, and the contents thrown
into water. The surface of the iron becomes converted into steel by the absorption of the carbon, and
beautiful colors are produced, the variegation of the color being affected by the quantity of the iron.
The whole of the parts now return to the finisher, and the gun is completed.
Rifled barrels are only used for throwing balls; they are always much thicker and heavier than other
barrels, in order to render the aim more steady, as well as to admit of cutting the grooves with safety.
Rifling consists in cutting a number of grooves in a spiral direction down the inside of a barrel,
usually from seven to fifteen, dividing the interior surface into lands and furrows, the sunk parts being
called the furrows, and the original surface left, the lands. In order to diminish friction, as well as to
impress the ball more readily, the lands ought to be narrower than the furrows. The object of rifling
is to give to the ball a rotation coincident with the line of its flight, and thus to correct the variable ro-
tation which every ball, passing freely along a smooth-bored barrel, receives from its friction against the
sides. The latter rotation never can coincide with the axis of the barrel, but must have a tendency to
deflect the ball from the line of aim, according to the last impulse it may receive on quitting the barrel.
Rifling also corrects any inequality in the density of the ball itself, by causing it to present alternately
every part of its surface in its passage through the air.
The usual method of rifling a barrel is by means of a long square bar, or rod of steel, which is twisted
to the required degree of curvature, and then accurately ground with oil and emery in square holes, 80
as to render every portion of its length precisely equal in curvature, which operation requires consid-
erable care and time. There are generally several rods of this kind to each rifling-bench, of different
curves, 80 as to vary from three-fourths of a turn, to a turn and a half, in three feet; but should any
other curve be required for experimental purposes, a new rod must be made for each, which becomes
expensive.
A rod of this description is correctly fitted into square holes, in two puppets, or heads, similar to
those of a lathe, through which it can be freely drawn backward and forward by means of a cross
handle, turning on its centre, to which is attached a dividing-plate to regulate the cuts or grooves. The
barrel being bored perfectly true, is fixed to the end of a long bench opposite to, and in a direct line
with, the rifling-rod at the other end. A piece of wood is turned to fit the barrel, in which a longitu-
dinal groove is sunk to receive the cutter, which is made of tempered steel, and has ten or twelve
sloping teeth in it. The piece of wood screws on to the rifling-rod by means of an iron ferrule; and at
the commencement the teeth of the cutter only project very slightly beyond the surface of the wood.
The cylinder of wood being entered into the barrel, the rifling-rod is pushed forward, and the projecting
teeth of the cutter make a faint groove in a spiral direction down the inside of the barrel: the rod is
worked backward and forward, until the teeth cease to cut, when the wood is withdrawn, and the rod
turned an equal division of a circle by means of the dividing-plate, according to the number of grooves
intended to be made: it is again entered, and another faint groove cut, and so on, until all the grooves
are sunk to the same depth as the first. The wood is again withdrawn, and the cutter elevated a
little, by taking it out of the groove in the wood, and placing underneath one or two slips of writing-
paper soaked in oil; the cutter being replaced, the same operation is repeated as at first, and the
grooves are gradually cut to the desired depth by the successive addition of thin slips of paper. When
the rifling is completed, an iron rod is placed in the centre of the barrel, and melted lead poured in, 80
as to occupy about eight inches of the barrel; which lead, of course, takes a perfect cast of the interior,
and is afterwards charged with oil and fine emery, and drawn up and down the barrel to polish the in-
side, and remove the sharp edges left by the cutter. This operation is called draw-boring.
A barrel can be as accurately rifled by this means as by any other, if the rods be correctly made;
but an improvement in rifling machines has been made, by which the twisted rod is altogether dis-
pensed with, and any required curvature given by a round rod. The principal advantage of this
machine is the facility it affords of varying the curvature of the spirals at pleasure, from a straight line
to two turns in three feet. A long square horizontal bar, which moves at each end in segments of a
circle, is attached to the centre of the bench: this bar can be fixed at any angle of inclination: above
this is a carriage freely traversing a railroad, and in the middle of this carriage is the dividing-plate and
rifling-rod, the latter being made to turn by means of a pinion-wheel and rack-work, which slides on the
horizontal bar as the carriage is pushed backward and forward; all the other arrangements of wood
and cutter being the same as with the twisted rod. This machine is now generally employed for best
rifles, and the old plan for military rifles.
Machinery for the stocking of muskets has been adopted to a considerable extent in Europe and in
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this country; the barrel, lock, and furniture being entirely let into the wood by this means. The
machinery for turning gun-stocks, used only, we believe, in the manufactory of muskets, differs but little
from the lathe for turning irregular bodies; of which machine two examples are given under the article
LATHE, which see. The following machine for turning gun-barrels is in general use in the foreign govern-
ment workshops.
GUN-BARRELS, Lathe for Turning. The object of this machine is to perform an operation entirely
different from that produced by the several motions of the common turning-lathe. In this case, the
curve required to be turned, on the whole length of the musket-barrel, is of an irregular form. This,
as will be seen by Figs. 2209, 2210, 2211, and 2212, is effected by a very simple contrivance, as
follows:
2209.
2210.
FAY & GULICK.
61
The bed b is secured by three bolts a' a' a' to the side frames or standards a a, which have also fixed
to them a tank o for receiving the waste oil and the iron turnings from the barrel being turned; on
the top of the bed is placed the headstock frame i, for carrying the several parts of the machinery and
on the mandril d are the tight and loose pulleys for giving motion to the machine: the centre c' of this
mandril is adjusted by the back centre c". By the two sets of spur-wheels and pinions a double motion
is produced, the forward by f and the backward by g, which are alternately worked by means of the
small clutch h, thus giving a revolving motion to the square-threaded screw.j for advancing the tool-
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frame l along the barrel to be turned; this motion is made self-acting by means of two small bars PP
fixed to the clutch-lever, having projecting pieces on their sides, with which the frame 1 comes in con-
tact, and pressing against them, draws them and engages the clutch in the wheels for giving the oppo-
site motion, while the object of the handle h' is to disengage it by hand. The spindle on which these
small wheels are fixed runs freely in brass bearings fitted to the headstock i.
On the opposite end of the machine is the headstock m, having an adjustable centre c', worked by
the screw and handle m", and may be fixed in any required position by a small set-screw m""; this
head can be moved along the bed b, to suit the length of any barrel n, and by the cross-bar and bolts
m' may be secured to it. The musket-barrel to be turned is slid on the long bar or mandril n', which
it fits very tightly. One end of this mandril is then dropped in the chuck e for carrying it round, while
it is centred at both ends in the centre pieces c' c'.
2211.
References of Figa. 2209, 2210, 2211, and 2212.
a, Standards for supporting the bed.
a, Bed of machine.
a Tight and loose pulleys.
d, Mandril with centre pieces c' c' and back centre c".
a, Chuck.
f, Spur-wheels and pinions for producing the forward mo-
tion.
8. Spur-wheels and pinions for producing the backward
motion.
4, Double clutch for changing the motions worked by
the lever h'.
is Headstocks.
j, Square-threaded screw for working alternately the
frame 1 for carrying the tool.
k, Curved bar screwed to the side of bed.
I Frame or chuck for carrying the tools r and securing
the barrel in its proper position by means of the rack
segment " and the vertical rack and weight i".
m, Movable headstocks fixed to the bed by cross-bar and
bolts m', the centre c working through it by the
screw and handle m", which may be fixed by a set-
screw m".
m, Barrel being turned fixed on a long mandril or bar n'.
o, Tank for receiving the turnings and waste oil, fixed to
the standards.
P, Sliding-bars fixed to the clutch at one end, by which
means the machine is made self-acting.
2212.
The most curious part of this machine is the frame 1 for holding the tools, and likewise the barrel of
the musket being turned which latter operation is rendered rather difficult from the irregular shape of
the barrel. Fig. 2211 shows a section, looking at the frame i, which consists of a back plate, on the
face of which is a brass piate with the eccentric grooves shown by the dotted lines struck from different
centres; between the latter plate and the back plate are four dies sliding in V'a, having ribs working
in the above grooves, which, not being concentric, press them against the barrel, and thereby hold it
firmly while the tools l' are turning it; but as the diameter of the barrel alters, it is necessary to loosen
the dies, in order to allow the frame i, of which they form part, to slide along the bed on its V's. This
is thus effected a curve bar or template k, suitable to the curve required by the barrel, is firmly
screwed to the side of the bed, its upper edge k, Fige. 2211 and 2212, being of the shape of a V, on
which the lower part of the rack 1"" slides, the upper part working at the same time in the V's screwed
to the projection given to the back plate 1 by three screws. Thus the motion produced by the curve of
the bar k is transmitted through the rack and the segment " to the grooved plate on which the latter
is fixed; the result of this is the tightening or loosening the four dies, which must naturally be the case,
as they have ribe working in the grooves, which they are compelled to follow. By the weight sus-
pended from the vertical rack, any irregular motion that might take place is entirely obviated, it being
kept firmly working on the upper surface of the curved bar k, while the small handle is provided for
the purpose of raising it by hand when required. There are two tools l', Fig. 2211, fixed to one of the
four dies already described; the one farthest from the frame 1 is for rough turning, while the other
follows it, giving the finishing cut.
A small bearing is provided on the bed for supporting the outer end of the screw j, and the standards
are well secured to the floor by bolts for that purpose.
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This machine is capable of turning and finishing three barrels per hour; and similar machines are in
use at the Armory of Enfield, and twelve of them, in conjunction with a complete set of machinery for
making muskets, are at work in the Imperial Armory at Constantinople, besides machines for the
French government, and for the Pasha of Egypt.
Jennings' Patent American Rifle.-This weapon is, without doubt, the simplest, and at the same
time one of the most perfect and effective of breech-loading arms. The gunpowder is contained within
the ball, which is elongated for that purpose, something in the shape and appearance of a sewing thim-
ble, closed at the end by a perforated cork. The range of the gun is very great, while from its sim-
plicity it may be used for a long time without cleaning. The inventor is now engaged in simplifying
the machinery of the lock still more, and arrangements have been perfected for manufacturing them on
a large scale.
The appearance of the gun is 80 like the common percussion gun that an engraving is not necessary.
The following description and reference to the mechanism of the lock will be sufficient. The agent for
the sale of these weapons is C. P. Dixon, 177 Broadway, New York.
To raise the hammer or cock.-Put the right thumb on the hammer, and the right forefinger in the
trigger-ring, and as the hammer is raised push the trigger-ring forward, or in other words, when the
thumb and finger are 80 placed, the simple turning of the hand, the thumb back and the finger forward,
brings down the toggle 4, Fig. 2213, which
is behind the breech-pin, (this is necessary
from the fact that a spring in the breech-pin
1 catches in the tumbler of the lock as the
hammer is raised, breaking the breech-pin
2213.
out from any stick there may be in the bar-
rel,) and allows the breech-pin to be forced
quite back; the cartridge can then be placed
in the opening on the side of the lock, then,
by pulling the trigger-ring 3 back, the car-
tridge is forced into the barrel, taking at the
same time a priming (percussion pill) from
the magazine on top, (which will hold from
50 to 70 pills,) and throws up the toggle in
the rear of the breech-pin, when a harder
pull fires the piece, which is effected by
forcing the fire from the pill, through the touch-hole into the hole in the centre of the cork, in the car-
tridge. It is well to put in a cork or small wad to hold the first cartridge back against the breech-pin,
though this is not absolutely necessary; after the first discharge this is not required, as the cork is left
in the barrel, and is pushed out by each succeeding cartridge.
To clean the rifle.-Knock the pin out that secures the barrel to the breech, take off the barrel
and the lock-the forward screw to the lock having a slight mark to distinguish it from the other-then
take out the separate parts. When cleaned, put in first the button with the countersunk side down,
2214.
2215.
then the breech-pin, dropping it in 80 that the tail of the button will come between the two pins on the
top of the breech-pin; then the pinion 2 with the dotted tooth in the last tooth of the breech-pin when
it is clear forward, on which there is also a dot; then put in the trigger-rack, placing it as far back as
it will go, then the toggle; then put on the lock, leaving the breech-pin clear forward, as only in this
position will the end of the spring in the breech-pin fit into its place on the tumbler.
The Prussian breech-loading rifle.-The Prussian rifle, known by the name of the Zund Nadel,
(darting needle,) has a number of points about it very different from all other breech-loading fire-arms,
but we will state three of them before describing the engravings, to make the description easier to un-
derstand. First, it uses a different cartridge and no detonating powder, but a friction needle-darting
needle, (zund nadel,) which pierces the bottom of the cartridge and ignites the powder by a friction
combustible priming. All this is done inside, and it is certainly as efficacious in wet as in dry weather.
Second, an air-chamber behind the cartridge, in which the expanded air acts to force out the ball.
Third, the sliding breech-pin, and the manner of operating and fastening it in an inclined butt of the
breech.
Fig. 2216 is a view of the breech-pin separated from the barrel.
Fig. 2217 is a longitudinal vertical section, showing the interior.
Fig. 2218 is the cartridge. A is the picket bullet; B the friction combustible priming; C the paper-
machie case.
Fig. 2219 is a plan view of the rifle, and Fig. 2220 a side view. The same letters refer to like parts.
here is a tube behind the breech of the barrel, forming a chamber, and there is a slot on its top for the
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GUN-BARRELS.
breech-pin to slide in. The breech-pin can be taken out entirely by unscrewing the cap Y. This IS
best seen in Fig. 2220: A is the barrel; it is enlarged at the breech to receive the breech-pin, the office
of which is to open to put in the cartridge, and shut to enclose it perfectly, &c. B is the breech-pin
with a short screw C, Fig. 2216, on its forward end, which, by a quarter turn, locks into the breech-butt
of the barrel. G is a handle to operate the sliding breech-pin, which is of a tubular form. The breech-
pin slides in the tube D. F is a projecting piece of the breech-pin, to guide the said pin when the cap
Y is off and the pin put in the tube, also to guide it back and forth. The forward end H of the tube D
is made of the form of the segment of a helix, 80 inclined that when the sliding breech-pin is pushed
forward, after the cartridge is inserted in the breech-butt of the barrel, and then turned to the right to
screw into the breech of the barrel, the forward shoulder of the projection F acting on the said inclined
2216.
X
2218.
3
A'
2217.
recess, will aid the thread in forcing in the breech-pin, and, during the discharge, will aid the screw-
thread in resisting the recoil. In this way the breech-pin is held firmly in its place during the discharge
of the piece-a very important combination indeed. The forward end of the breech-pin is a strong
hollow air-chamber I, behind the cartridge, and the air contained therein is expanded by the combustion
in the cartridge, and aids to force out the ball; this is in accordance with scientific experiments. In the
centre of this hollow chamber is a projecting piece in which is drilled a centre hole, through which the
darting steel-needle K projects and slides, Fig. 2217. This is the needle that pierces the cartridge and
inflames the priming. The needle is secured to a small fly-spring carrier, something like that kind used
in small guns for juveniles. L is this carrier; it has a coiled spring o abutting against its forward end,
the dots, Fig. 2217. and abutting with its back end against a collar of the breech-pin, seen inside of the
catch P of the carrier, which is attached by a screw to the head M of the needle. To load, the handle
G is turned to the left, and the breech-pin drawn back in the top alot of the tube, when the carrier disk
P is caught by the sear R of the trigger, the carrier held, and the cartridge is inserted in the butt of the
2219.
c
2220.
barrel. The breech-pin is then moved forward, and the shoulder turned into the inclined recess. By
drawing the trigger S the carrier is disengaged, and the spring darts the needle K into the end of the
cartridge to effect the discharge. U, Fig. 2216, is a ring of the tube, into which the breech-pin slides
accurately, the said ring being placed forward of the disk P of the carrier. V is a bar which fite into
the slot of the tube, and when the breech-pin is forced home and this bar pushed forward. it covers up
the slot, and its forward end is fitted to enter a recess W in the breech-pin. When the breech-pin is
locked in its place. and the bar V pushed in its place, there is thus a most effective bracing to prevent
the breech-pin yielding in the least to the recoil of the discharger. X is a spring fitted into a recess of
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GUN-BARRELS.
927
the breech-pin, and it has a projecting catch (not seen) which passes into a hole in the breech-pin, to
drop before the carrier when it is drawn back, to hold the carrier during the act of loading, to prevent
accidents by the touch of the trigger; but when the gun is loaded, by pushing forward the bar V, the
needle-carrier is relieved from this to be under the complete control of the trigger. Z is an incline on
the bar that goes under the spring X, and draws out the stop in the interior when the bar V is pushed
forward. All this is done at the breech.
The gun itself is compact and simple. The whole of the light cavalry of the Prussian army are to be
provided with it. The inventor is Mr. Charles Hartung, of Prussia, now of New York. The assignee
is John B. Klein, Esq., of Laight street, New York. It is patented in the United States.
Colt's improvements in fire-arms, patented in 1849, consist in certain improvements upon that con-
struction of guns and pistols which has a cylindrical revolving breech-piece, provided with a series of
parallel chambers for containing a series of charges, which charges, by the revolution of the breech upon
its shaft, may be successively brought into a line with the bore of the barrel, and be severally discharged
through the same.
In the following figures the improvements constituting the present invention are shown as applied to
this construction of fire-arms, which formed the subject of a patent granted to the present patentee on
the 22d of October, 1835.
Fig. 2221 shows a pistol made according to this invention; Fig. 2222 is a side view, showing the lock-
frame and recoil-shield in section; and Fig. 2223 is a longitudinal section, taken through the middle of
the breech and barrel. a is the breech, containing six chambers, as shown in the end view, Fig. 2224,
in the back of each of which a nipple is fitted, as shown in end view at Fig. 2225, and in section at Fig.
2223, to receive a percussion cap for firing the charge. This breech is supported by and is capable of
turning on a spindle or arbor b, which is welded or fastened to and forms one piece with the recoil-
shield c*, it being in a line parallel to the axis of the barrel. The shield is itself a continuation of the
lock-frame c, the whole being formed out of one solid piece of metal By referring to the longitudinal
section, Figa. 2222 and 2223, and to the cross section, Fig. 2226, the peculiar construction of this lock-
frame and shield will be readily understood. The shield c* stands up at right angles to the frame c,
and forms a round head (somewhat like a bolt-head) to its shaft b. The upper part of the shield is
recessed to receive the hammer d, when it is thrown forward to effect the discharge of the pistol; and
a recess is also made in the piece of metal which constitutes the lock-frame and shield, (see Fig. 2222,)
to receive the parts which respectively revolve the breech to bring round the charges in a line with the
barrel e, and lock the breech to the frame for the purpose of insuring that the charges shall be in a line
with the barrel before the firing takes place. When the pistol is on half-cock, or in the position shown
at Fig. 2223, the breech is free to turn round on its arbor in the direction of the arrow, Figs. 2221 and
2222. It may then be loaded and primed with facility, without being removed from its place, as was
formerly requisite in charging this construction of revolving-breech fire-arms; a free space being left in
front of the mouths of the chambers, as will be seen by referring to the end view of this breech, Fig.
2224, which shows the sectional area of the barrel and its appendages in dotted lines. The barrel e is
supported in its place by the end of the spindle b, fitting into a socket in a bracket-piece, forming one
piece with the barrel, as shown best at Fig. 2223. Against the end of this socket the spindle is made
to abut, and thus to determine the exact position of the barrel with respect to the face of the revolving
breech. To keep the barrel secure in its place, a key f is introduced through slots in the bracket or
projecting piece of the barrel, and through the spindle b, its upper edge acting on the forward end of
the slot in the spindle, and its lower edge acting upon the lower end of the slots in the bracket of the
barrel, the effect of which is to draw the barrel towards the cylinder breech and lock-frame as the key
is pressed in; and pins, projecting from the end of the lock-frame, enter corresponding recesses in the
bracket piece of the barrel. The key f has a spring-catch, which rises when the key is forced home,"
and, by its turned-up end coming in contact with the edge of the slot through which it has been passed,
it will prevent the key from getting loose and shaking out of its place by the concussion of the firing.
This object is further insured by the insertion in the barrel-piece of the screw 1, the head of which would
come in contact with the turned-up end of the catch, if it had escaped past the edge of the slot, and
prevent it from dropping, or even being drawn out; this screw must, therefore, be removed before the
key can be displaced. Jointed to the bracket part of the barrel, by a pin 2, is a lever g, which is kept
up in a position parallel to the barrel by a spring-catch at its other end taking into a catch on the lower
side of the barrel. To this lever a plunger h is connected by a pin 8, taking into a slot on the outer
end of the plunger. The inner end of the plunger slides in a guide made for it in the bracket-piece of
the barrel. This plunger is intended to act as a ramrod, and to drive the bullets or cartridges into the
several chambers of the breech, consecutively as they are brought in a line with the plunger.
To effect this the catch of the lever g is disengaged. and the lever is brought into the position shown
by dots in Fig. 2222; the plunger is thereby driven forward and made to ram the bullet (which has
been previously inserted in the end of the chamber, now brought in a line with the plunger) down into
its proper place in the chamber; the plunger is then drawn back, and the next succeeding chamber
brought in a line therewith, when the lever g is again brought into the dotted position, to thrust the
plunger forward and ram down another charge and thus successively all the charges are acted upon.
By referring to the drawing, Fig. 2223, it will be seen that the mouths of the chambers and the inner
end of the barrel are chamfered at their edges. This bevelling of the edges of the chambers is to pre-
vent the lateral discharge between the breech and the barrel from igniting the powder in the other
loaded chambers; for the ignited matter, by coming into contact with the bevelled edge as it crosses
the mouths of the chambers, will be deflected outward and effectually thrown off, and be prevented
from reaching the powder in the chambers. The bevelling of the end of the barrel is intended to pre-
vent its cutting the ball in its passage from the chamber.
At Figs, 2226 and 2227 it will be seen that a hollow is made in one side of the shield c#: the object
of this is to expose the ends of the nipples as the breech is revolved, and thus to allow of the percussion
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928
GUN-BARRELS.
caps being readily placed thereon. The hammer a turns on a pin 4, in the lock-frame c; and it is pro-
vided with stops or catches for the end of the trigger to abut against, as usual, and hold it at whole or
half-cock, as required. To the hammer is jointed a hand-catch i, with the spring k attached, Fig. 2222,
which is pressed forward into contact with ratchet-teeth formed on the end of the breech, and allows
the hand-catch to recede for passing below a second tooth of the ratchet. l is a rocking lever, supported
by a pin in the lock-frame c, and carrying at one end a bolt, which is intended to enter, at certain times,
into the recesses 5 5 in the periphery of the breech, a bearing-spring m, Fig. 2228, giving it always a
tendency to rise for that purpose. The other end of this lever is made thin, 80 as to be capable of
yielding laterally and recovering its position, thus allowing a stud 6 (which projects from the hammer
and has a chamfered or bevelled face) to pass the lever without disturbing the position of the bolt-end
when the hammer moves forward to fire the charge; and yet, when the hammer is drawn back, to pre-
sent an obstruction to the stud 6, and be thereby tipped into the position shown at Fig. 2223, which
movement will unlock the breech. As long as the hammer remains at half-cock the breech will be free
to turn upon its spindle for the purpose of being loaded; but when the stud has passed the end of the
lever, the spring m will again force the bolt of the lever into its original or locking position. The action
2228.
2221.
0000
2226.
8
2223.
LESS
of drawing back the hammer to its furthest extent (the bolt being first relieved) will raise the hand-
catch i, which, being brought in contact with a ratchet-tooth on the breech, will turn the breech round
in the direction of the arrow, Fig. 2222, to the extent of one tooth, and thus bring up a loaded chamber
in a line with the barrel ; and, in succession, the act of cocking will bring all the loaded chambers in
like manner round in a line with the barrel and hammer to be discharged. In order to insure the
insertion of the bolt of the lever I into the recesses 5 5 as they severally come round, and thereby to
hold the breech firmly while the discharge takes place, a shallow channel or guide is formed up to the
edge of each, as shown in the figures, which will make the bolt feel its way to the recess and enter it
more certainly than if it were required to fall into the recess suddenly. To prevent the fouling of the
spindle and breech, a helical groove is formed upon the spindle, as shown at Fig. 2223, the edges of
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GUN-COTTON.
929
which will more effectually prevent the smoke from passing between the breech and spindle than if the
whole periphery of the spindle were in contact with the breech; and at the same time these edges
will, as the breech is rotated, scrape off any matters that may have become deposited in the central
bore of the breech, and deposit it in the grooves. By this means the contact surfaces will be kept
clean, and the breech, which would otherwise foul after a few discharges and become fixed, will be free
to turn on its spindle, for a long period, without requiring any cleaning.
Fig. 2228 represents in side view, and Fig. 2229 in plan view, a rifle, carbine, musket, or shot-gun,
with revolving breech. As the several improvements before described, with reference to the pistol,
are equally applicable to guns for military and sporting purposes, the patentee gives merely a descrip-
tion of the modified arrangement of apparatus for ramming down the charges, as represented at Figa.
2228 and 2229. In this instance, instead of the plunger being applied below the barrel, it is attached
to the side thereof. a is a bracket projecting from the side of the barrel, and to it the lever b is jointed
by a pin 1. c is the plunger, having at about the middle of its length a joint 2; it is forked at one end,
and embraces the lever b, to which it is jointed by a pin 3, and the cylindrical end of the plunger works
between guide-pins 4 4 on the barrel. d is a spring-catch. riveted to the plunger c, and capable, when
the lever b is laid parallel with the barrel, of taking into a notch cut in the bracket a. By means of
this spring the ramming apparatus, when not required to be used, is retained in the position shown at
Fig. 2228; but by drawing the lever b into the position shown at Fig. 2229, the catch will be imme-
diately disengaged from the notch.
The patentee claims, First, making the lock-frame and recoil-shield in one and the same piece,
whereby all possibility of the parts getting loose after repeated discharges is prevented. Secondly,
the general arrangement of the lock and apparatus for turning and locking the rotating cylinder breech,
Thirdly, the general arrangement of the parts, whereby the operations of loading and priming may be
effected without disconnecting the breech, as was heretofore requisite. Fourthly, the application to
guns and pistols of the lever apparatus for ramming down the charges into the several chambers with
great expedition and effect-the same being a substitute for the loose ramrod, Fifthly, the chamfering
.he mouths of the chambers and the inner end of the barrel; also the grooving of the periphery of the
breech-spindle; likewise the making sunk-guides to the locking recesses on the periphery of the breech;
and, further, the means of insuring the proper position of the barrel with respect to the face of the
breech.
GUN-COTTON. To Professor Schönbein, the entire credit is due of discovering and making known
the various useful purposes to which gun-cotton may be applied, although its actual discovery dates
from a period prior to that when Schönbein published his experiments.
In 1883, M. Braconnot observed, when starch was heated for a short time in strong nitric acid, until
complete solution had been effected, and the solution was poured into a large quantity of cold water,
that a white pulverulent amorphous substance gradually subsided, which, on being dried, was highly
combustible, and burnt without leaving any residue. This substance was called xyloidine. M. Pelouze,
in 1838, repeated the experiments of Braconnot, and found that paper, linen, cotton, and other ligneous
substances, when submitted to the action of strong nitric acid, (sp. gr. 1-5,) for a few minutes, and then
well washed with water and dried, possessed the same properties as xyloidine, without having lost,
however, their original form and appearance. M. Pelouze was inclined to believe with chemists in
general, that this was only another form of the same substance; he also threw out a surmise, that the
substance might be applicable to certain useful purposes, especially in artillery. The same chemist, in
conjunction with others, has, however, since shown, that these two substances are not identical. That
the substance prepared by immersing paper, linen, cotton, &c., in nitric acid, contains more oxygen, and
consequently more nitric acid than the xyloidine of Braconnot, and the name of pyroxyline or pyroxyle
has consequently been given to it. The gun-cotton of Schönbein is probably this latter substance, or
some body closely allied to it.
The plan adopted for the manufacture of this compound is as follows: cleansed cotton is immersed
m a mixture composed of equal parts of concentrated nitric and sulphuric acids, or, according to Schöng
bein, of 3 parts sulphuric acid, and 1 of nitric acid, of sp. gr. 15, for about 10 to 15 minutes, and in
order to prevent accidents, no portion of the cotton should be above the level of the liquid. The acid
should then be pressed out, and the cotton which remains impregnated with it is well washed with
water, until no acid reaction is perceptible to the tongue; it is now dried rapidly at a temperature not
exceeding 212° F. Care should be taken, in drying this substance, to allow a free current of air to pass
over it, and to spread out the cotton as much as possible, in order to prevent its forming into dense
masses, which are much more liable to explode. It is, indeed, probable, that the method of drying in
stoves, practised at first in Messrs. Hall's manufactory, was the cause of the explosion which occurred
there, and which cost several persons their lives.
No minute description of the mode of preparing gun-cotton upon a manufacturing scale has been
published up to this period, and the foregoing notice, which indicates the plan practised by M. Susane,
at the Direction des Poudres et Saltpêtres, must suffice to give a general view of the process, which is
no doubt carried out with slight differences, although the same in principle, in the different manufactories.
With regard to the composition of gun-cotton, nothing certain is established. The analyses which
have been made of it, and which are numerous, do not accord, and tend rather to prove that several
products may result from the action of nitro-sulphurio acid upon cotton, paper, dic., depending, amongst
other things, upon the state of concentration of the acids used, the time of immersion, &c.
The properties of gun-cotton are very extraordinary, and create a greater degree of astonishment, in
consequence of its outward appearance bearing the strictest resemblance to ordinary cotton wool, which,
however, is not so harsh to the feel. It is insoluble in water both hot and cold, and when removed and
dried, is found to have lost none of its original properties; acids have also no action upon it, and this
effectually distinguishes it from xyloidine. The best solvent for gun-cotton is acetic ether, and this sub-
stance may be used for rendering it perfectly pure. It explodes violently when heated to 356° F,, or
117
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930
GUNPOWDER.
on ignition, leaving scarcely any residue, and creating very little smoke. The temperature at which it
is thus decomposed, is 80 much below that at which gunpowder explodes, that the cotton may be lightly
placed upon the surface of gunpowder, and detonized by a red-hot wire without setting fire to the pow-
der. Friction of the ordinary kind will not explode gun-cotton, but when placed on an anvil, and pow-
erfully struck with a hammer, the heat generated by the stroke causes it to detonate. With reference
to the projectile force of gun-cotton, as compared with gunpowder, there appears reason to apprehend
that its action, in its present form, is too rapid, and resembles too much that of the fulminates, to ren-
der it applicable to the purposes of artillery. The gaseous products from its combustion are also such
as cannot be altogether resisted by fire-arms, although, if air be absent, no great amount of corrosion
can ensue; and as it has been found that gun-cotton impregnated with chlorate of potash or nitre has
a still more powerful effect than that prepared in the usual manner, the addition of these substances
would at the same time tend to modify the corrosive action of the acid products of combustion. As a
substitute for gunpowder in all mining and blasting operations, however, the superior local force of the
powder-cotton will be highly valuable; and it has indeed been found to effect as much as four times its
weight of powder. In the pyrotechnic art it will probably also be extensively used, and paper pre-
pared by the method of Pelouze, and moistened with solutions of nitrate of strontia, sulphate of copper,
and nitrate of baryta, yields very beautiful red, green, and white fires.
GUN METAL A species of brass employed in casting cannon, and used also in the wearing parts
or joints of machinery. This alloy should consist of 9 parts of copper and 1 of tin, but no zinc. It
answers well for valves.
GUNPOWDER, description of machines used in the proof of. Cannon pendulum and its ballistic
pendulum, of the Washington Arsenal, Figs. 2230 and 2231.
The pendulum-block.-The pendulum-block is of cast-iron, in the form of a hollow frustrum of a cone,
with a hemispherical bottom. In order to give it the requisite strength, the block is closely hooped
with wrought-iron over all the conical part, except in the places where it is embraced by the suspension
straps; for this purpose the block was first turned, and the hoops were accurately reamed in a lathe,
and then shrunk on to their places, using in this operation only heat enough to set the hoops closely
to the cast-iron.
2230.
2231.
In order to facilitate the adjustment of the centre of oscillation of the pendulum, by throwing the
weight as far as possible from the axis of motion, the block was made thicker on the lower side than on
the upper, by placing the core of the hollow part above the centre of figure, thereby bringing the centre
of gravity of the block 0.5 inch below its axis.
The opening in the face of the block is partially closed by an iron plate, which is held fast by bolts
set in the block, and which serves to retain the sand used for filling the hollow of the block. In the
centre of this plate is a circular opening 16 inches in diameter, through which the ball passes, and the
point struck by the ball is marked by the hole made in a sheet of lead, (of about 31 lbs. to the square
foot,) which is placed over the opening in the plate and retained by a washer, or smaller iron plate,
bolted to the large one; vertical and horizontal scales, drawn on the face of the small plate, serve, by
means of an easy reference, to measure the position of the point struck by the centre of the ball.
Manner of forming the core of the pendulum-block.-The hemispherical bottom of the core is formed
of a block of lead, which serves to counterpoise the weight of the front part of the pendulum-block, and
facilitates the adjustment of the axis in a horizontal position, by bringing the centre of gravity of the
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system nearly in the middle point between the suspension straps; this lead forms also a sort of cushion.
to receive the impact of the balls, and to prevent them from striking against the cast-iron, in case they
should penetrate through the sand which forms the chief part of the core of the pendulum-block.
The sand which receives the impact of the balls is contained in cases made of strong leather stretched
over iron frames; the frame consists of two wrought-iron hoops, connected together by ribe of the same
material; the diameter of each hoop is 0.75 inch less than that of the core, at the place which it is to
occupy each hoop is made in three segments, and the corresponding segments of the two hoops which
form one frame, are connected together, each pair, by three ribe of square iron welded to the hoops.
The leather which covers these frames is brought over the outer faces of the hoops and secured there
by rivets, the sections of each hoop being connected together by the leather covering only. When the
sand is compressed by the ball, the case or bag expands laterally, until it is supported by the sides of
the pendulum-block.
The ends of these cases are closed with boards of soft wood, about 1 inch thick; those which form
the bottom, or smaller end of the case, rest on iron pins which are set on the inside of the smaller
hoop; and those which form the head, or larger end, are kept in place by small nails driven into wooden
plugs in holes on the inside of the large hoop.
In order to fill the case or bag, it is placed on its small end, and the boards forming the bottom are
laid down on the pins intended to support them; if there are any openings through which the sand
might escape, they are closed with shavings, &c. The sand is then put in and settled with a small
rammer, such as a piece of an implement staff: when nearly filled, the bag is placed on the platform of
a balance, and its weight properly adjusted, after which the head is fastened in as before mentioned.
Four of these bags form a set for filling the pendulum-block the first or smallest one is 15 inches high
the second, 14 inches; the third and fourth, each 12 inches; an interval of about 3 inches is thus left at
the mouth of the block, which serves to admit any compensating weights that may be required to make
up the proper charge. These weights are in the form of large rings, made of iron of different sizes,
according to the weight required. The vacant space in the mouth of the block is requisite also for con-
taining the sand displaced by the shot. A small portion of this sand escapes through the hole made
by the ball in the sheet of lead on the face of the block.
The placing of the sand-bags in the block is facilitated by the use of a pair of large hooks, or tongs,
attached to a tackle and fall, suspended from the roof of the pendulum-shed and hanging just in front
of the block: when not in use they are drawn aside, out of the way of the pendulum, and hung on a
hook driven into the frame of the shed.
Manner of suspending the pendulum-block.-The block is suspended by means of four straps of
wrought-iron attached to a horizontal shaft of the same material.
The shaft terminates at each end in knife edges, made of hardened steel welded to the iron. These
knife edges are rounded on a radius of 0-06 inch; inside of the knife edges, the shaft has cylindrical
bearings which are turned with great care; the lower lines of the knife edges are in the surface of these
cylinders produced, and consequently the axes of motion, at the two extremities of the shaft, are in the
same right line.
The suspension straps terminate, at their upper ends, in collars which are accurately bored to fit the
cylindrical bearings on the shaft. In the lower parts of these collars are slots, which fit on correspond-
ing projections on the shaft and prevent the straps from turning the collars of the straps are also
pre-sed firmly, by means of keys, against the shoulders of the shaft. The two inner straps, from each
end of the shaft, pass to the front end of the pendulum-block; the outer ones, to the rear end. The
inner straps are straight, from the collars on the shaft to a point near the block where they take a di-
rection perpendicular to the axis of the block, which they embrace between the shoulders provided for
them. The outer straps are curved just below the shaft, 80 that at the distance of about 5 feet from
the axis, the two straps from each end of the shaft are brought into the same plane, passing nearly
through the axis of the block.
The work should be fitted together in such a manner that the line joining the centres of the two col-
lars for the pendulum-block, which are thus formed by the two pairs of straps, shall be in a plane per-
pendicular to the axis of the shaft at its middle point, and shall be also perpendicular to a plane pass-
ing through the axis of the shaft and the middle point of the line in question, which line coincides with
the axis of the block.
The pair of straps which embrace the front part of the block approach, above and below the block,
within 8 inches of each other, and are kept apart by iron transoms which terminate at each end in bolts
that pass through the straps, and are held by nuts on the outside. The other pair of straps come together
within 2 inches, and the bolts which serve to press them against the block pass through the flattened
heads of two large transverse bolts, the other ends of which are cut with a screw-thread. The ends of
these bolts pass through holes in the transoms of the front pair of straps, and the bolts have strong screw-
threads cut on their whole length, for a purpose which will be hereafter explained.
Between the pendulum-block and the shaft, the two straps from each end of the shaft are firmly
connected together by two pairs of flat braces, having shoulders which bear against the edges of the
straps; the upper braces are bolted to the straps, and they are connected together by a large cross-bolt
which passes through the middle of each; the lower braces are connected with the straps, and with
each other, by means of cross-bolts. All of these cross-bolts have bevel-washers against their shoulders
inside, and under the nuts, outside of the braces.
Supports of the pendulum.-The knife edges of the shaft rest in V's formed in dies of hardened steel,
which are set in cast-iron seats these seats are bolted down to large cast-iron plates, resting on the
tops of two stone piers, to which the plates are secured by long bolts let into the stone. On the upper
sides of the plates there are projecting ledges, between which the seats for the V's are placed, and the
position of these seats is regulated by means of wedges inserted between them and the projections on
the plates. The bolt-holes in the seats are made of an oblong form. in order to admit of adjustment
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so that the two V's of each pair shall be in the same horizontal line, and that these lines, in the two
pendulums, shall be parallel to each other.
The bottom parts of the V's are rounded on a radius 1-10th of an inch; and the inclination of the
sides is 80 arranged, with reference to that of the planes of the knife edges, as to allow the pendulum
to vibrate through an are of 30°.
The parallelism of the two shafts is verified by means of two plumb-lines, suspended to the ends of
a needle attached to each shaft in a direction perpendicular to its axis. Four other plumb-lines are
suspended in the axis of the gun and block, (on the front and rear of each,) and when the adjustment
is perfect, these eight plumb-lines should hang in the same plane.
Measurement of the arc of vibration.-The vibration of the pendulum is measured on a brass limb,
placed under the axis of the block and supported by wrought-iron chairs set in stone posts. A alider,
also of brass, moves on this limb, and is held at any point by the pressure of a light spring; the slider
is moved by an index attached to a bar connected with the lower ends of the suspension straps. The
limb is graduated in degrees and minutes, and the slider has a vernier which reads to two seconds.
The zero of the are is placed in the vertical plane passing through the axis of motion, and the face of
the index is also in this plane when the axis of the block is horizontal, or situated in the line of fire.
In order to have the means of verifying the adjustment of the limb, at any time, if necessary, two hollow
centres are screwed into the under side of the shaft, near each end, for the purpose of suspending two
plumb-lines that shall hang in the vertical plane through the axis of motion.
Gun pendulum.-The suspension-frame, the supports, and the general arrangement of the gun pen-
dulum, are similar to those of the ballistic pendulum, and it is therefore necessary to describe only the
manner of attaching the gun to the frame.
In order to provide for mounting guns of any calibre below a 32-pounder, the diameter of the circular
parts of the suspension straps is sufficiently large to admit collars of cast-iron which may be adapted to
the gun and made to fit on the trunnions, having shoulders to receive the straps; but the 32 and 24-
pounder guns, heretofore attached to the pendulum, having been made for the purpose, the projecting
pieces, to form the shoulders for the straps, were cast on the guns. In order to facilitate the adjust-
ment of the centre of oscillation of the pendulum, and also to have a gun which shall be perfectly safe
to use, with any charge up to 1 the weight of the shot, the 24-pounder has been made on the same
model as the 32-pounder, and the trunnions are omitted, as the piece is designed for use with the pen-
dulum exclusively.
Adjustment of the centre of gravity and of the centre of oscillation.-The two systems being nearly
symmetrical, with reference to the vertical planes through the axis of motion and the axis of the gun or
block, the centre of gravity of each pendulum was found nearly in the intersection of these vertical
planes, when the axis of the gun or block is horizontal; it is therefore necessary to provide only for cor-
recting the deviations caused by variations in the charge of the gun, or of the block. For this purpose,
adjusting weights are placed on the large screw-bolts which connect the front and rear straps above
and below the gun and the block; by sliding these weights backwards or forwards, the position of the
vertical line containing the centre of gravity is easily adjusted. These weights effect another very im-
portant purpose, in the adjustment of the centre of oscillation of the system, so as to make it coincide
with the axis of the gun or block.
The weight of the gun and block being very great, in comparison with that of the suspension-frame,
the centres of oscillation were found to be nearly at the proper height, and the adjustment of them was
readily effected by placing weights on the lower screw-bolt, which has the effect of lowering the centre
of oscillation; the upper screw-bolt would be made use of in the same manner, in case the centre of
oscillation should be found, by any change of circumstances, to be too low. These screw-bolts are flat-
tened, or planed off, at the sides, in order to allow the weights to slide on them more readily. The
weights are cylinders of various heights, having slits of the thickness of the screw-bolt, to facilitate
placing and removing them. The slits are lined with thick sheet-iron to prevent the weight from being
cut by the screw, and the height of the slit is 80 regulated (for convenience in calculation) as to bring
the centre of gravity of the weight in the axis of the bolt on which it rests. The weights are made of
lead, with about 6 per cent. of tin; they are moved on the bolt, and are also held in place, when set, by
means of large nuts with handles, of which there are two on each bolt. To prevent these nuts from
being pressed into the weights by their reaction in the recoil of the pendulum, broad iron washers are
placed between the weights and the nuts, and the front weight for each pendulum is made of a shell
of cast-iron 1 inch thick, filled with lead.
Weight of the pendulums.-The weight was ascertained to be as follows:-
lbs.
Weight of gun-frame complete
2,811
"
32-pounder gun
7,689
Total of gun pendulum
10,500
ballistic pendulum-frame complete
2,847
a
pendulum-block, (empty)
6,368
"
face-plates and bolts for do.
143
Total ballistic pendulum
9,358
Position of the centres of gravity of the pendulums.-The position of the centre of gravity of each
system was determined by balancing the frame complete on the edge of a square steel bar, placed
parallel to the axis of the shaft. The place of the centre of gravity of the gun and the block being
known, that of the whole system is easily calculated.
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The results of this calculation were verified by actually balancing, in a horizontal position, the whole
pendulum, with the gun and block in place.
Gun.
Block.
Inches.
Inches.
Distance from the axis of motion to the centre of gravity of the frame
1128
114'13
Distance to the centre of gravity of the gun or pendulum-block, (empty)
195
1955
Distance to centre of gravity of the system, (by calculation)
112.8 X 2811 + 195 X 7689
=
172994
10,500
2847 X 11413 + 6368 X 195.5 + 143 X 195
170787
9358
Distance to centre of gravity of the system, by trial
1728
1708
Do. mean; taken as the true distance
172.9
1708
The height of the centre of gravity of each pendulum in this condition being known, it is easy to
make the necessary correction for the addition of the adjusting weights, and for the weight of the core
of the block. For this purpose it is sufficient to observe that the centre of gravity of the adjusting
weights, being in the axis of the lower screw-bolts, is, in the gun pendulum, at 215 inches from the axis
of motion, and in the ballistic pendulum, at 219 inches. The centre of gravity of the hemisphere of lead
in the bottom of the pendulum-block is in the axis of the block, or 195 inches from the axis of motion
and that of the conical part of the core is 0.66 inch above the axis of the block, or 19434 inches from
the axis of motion.
In the gun pendulum, when adjusted for use with the 32-pounder gun, a weight of 667 pounds was
placed on the lower screw-bolt.
In the ballistic pendulum there were
lbs.
a hemisphere of lead in the block, weighing
6261
an oak board over the lead
91
a sheet of lead on the face
8
4 sand-bags
965
adjusting weights on the lower screw-bolt
789
Under these circumstances, the distance of the centre of gravity of the gun pendulum from the axis is
10,500 X 172.9 + 667 X 215 1,958,963
=
175.41
in.,
11,167
11,167
and that of the centre of gravity of the ballistic pendulum,
9858 X 1708 + 648 X 195 + 975 X 19434 + 789 X 219 2,084,162-5
=
=
17729
in.
11,756 lbs.
11,756
The results of these calculations and measurements may be at any time verified, and in case of a
change in the pendulums, they may be corrected, by practically ascertaining the moment of the system,
i e., the product of the weight into the distance of its centre of gravity from the axis of motion and
this moment is a factor which enters into the formula for the computation of the initial velocity of the
ball. To ascertain the moment of the pendulum without dismounting it, it is sufficient to determine by
trial the weight which, acting at a given distance from the axis, will sustain the system, out of a verti-
cal position, at such an angle that the direction in which this weight acts shall be perpendicular to the
line drawn from the centre of the axis of motion to the centre of gravity of the system. If a be the
angle which this latter line then makes with the vertical, w the weight which balances the system, and
d the distance at which it acts from the centre of motion, then will the moment of the pendulum be
sin.a = P9.
Position of the centre of oscillation-The lengths of pendulums being to each other as the squares of
the times of vibration, or inversely as the squares of the number of vibrations in a given time, the
distance of the centre of oscillation from the axis of motion is determined by observing the number of
vibrations made by the pendulum in any given time, or the number of seconds required for a given
number of vibrations of the pendulum.
In the present instance this was determined by observing, with a chronometer which beats half
seconds, the time required for 500 vibrations of the pendulum, commencing in an arc of about one
degree and a half. The length of the seconds pendulum at Washington, (latitude 38° 53' 23",) being
391 in, the distance of the centre of oscillation of a pendulum vibrating 500 times in n seconds, will be
n2
X
391
=
;
500'
and in order that L shall be equal to 195 in., or that the centre of oscillation shall be in the line of fire
of the pendulum-gun, n must be = 1116.5 seconds.
In the gun pendulum, this adjustment of the time of vibration is effected by placing an additional
weight of 667 lbs. on the lower screw-bolt, as above mentioned, in ascertaining the position of the centre
of gravity. In the ballistic pendulum, when ready for use and loaded as above stated, the time required
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for 500 vibrations is 1116 seconds, and the position of the centre of oscillation is at 1948 in. from the
axis.
When the position o' of the centre of oscillation is accurately ascertained, for any given condition of
the system, the additional weight W, requisite to bring that centre into any other position, o may be
computed very nearly by the formula
w-pg(o-o),
Pg being the actual moment of the pendulum, and d the distance of the additional weight from the axis
of motion.
In consequence of the lightness of the frames, in proportion to the whole weight of the pendulums,
they are found to possess a great degree of sensibility when vibrating in an arc of 14°, they lose
about 36" in one vibration; in an arc of 4°, about 25". When set in motion in an are of 12°, the gun
pendulum continued to vibrate about 24 hours, and the pendulum-block (empty) about 30 hours.
Distance between the pendulums.-It was ascertained that, at the distance of 48 feet from the muzzle
of the gun, the pendulum would be but slightly affected by the blast, and it was therefore determined
to place the axes of the two pendulums 55 feet apart.
In order to intercept the blast of the gun as much as possible, a fixed screen of 2-inch oak plank is
placed 17 feet in front of the face of the pendulum-block, having a hole in it 12 inches diameter for the
passage of the ball. The protection afforded by this screen is such, that with a blank charge of t from
the 32-pounder gun, the vibration of the pendulum-block does not exceed 45"; which vibration, if pro-
duced by the impact of a ball, would require a velocity of only 0.85 feet.
The penetration of the 32-pounder balls, in the sand of the pendulum-block, is about 4 feet. It is
found that, in consequence of the great and sudden compression of the sand, produced by balls moving
with great velocities, the penetration does not increase with the charge; but the pressure against the
sides and bottom of the block is necessarily greater with higher charges, and under these circumstances,
the mass of lead in the bottom of the block is 80 much compressed and battered as to make it inexpe-
dient to fire with high charges (1 or I) from the 82-pounder gun, without filling the block with some
material affording a greater resistance than sand.
Service of the pendulums.-Open all the doors and windows of the sheds; observe whether the nuts
of the several connecting-bolts are screwed up tight, and whether the shoulders of the knife edges swing
clear of the seats. Wipe out the V's and oil them with a small quantity of clear oil.
1st. The ballistic pendulum.-Load the pendulum-block with the sand-bags, driving them in with
handspikes, 80 as to make them bear on each other; put on the face-plates with the sheet of lead pre-
viously adjusted between them.
Adjust, if requisite, the position of the centre of oscillation of the pendulum, and in order to maintain
this adjustment, let the sand-bags be always filled to the same weight as at first. If this cannot be
done, make up the correct total weight by placing some of the iron rings within the mouth of the block
Wipe the graduated are and move the adjusting weights on the lower screw-bolt, 80 that, the pendu-
lum being at rest, its index shall be in contact with the slider when the latter stands at zero; in this
position the axis of the block is horizontal: see that the nuts on the screw-bolts are set firmly against
the adjusting weights.
After the gun is fired, two men stop the vibrations of the pendulum-block, checking them gradually
with the hand, (or with a rope thrown over the breech,) and taking care not to displace the alider on
the arc.
Note the arc of vibration.
Take off the face-plates and ascertain the position of the point struck by the centre of the ball, by
referring the extremities of the vertical diameter of the hole made by the ball to the graduated scales
on the outer plate. If necessary, note also the lateral deviation of the shot. Withdraw the sand and
the ball, dc.; clean out the block with the rake and brush provided for the purpose.
2d. The gun pendulum.-The centre of oscillation is supposed to have been properly adjusted.
Wipe out the gun, insert the cartridge, push it home with the rammer, and measure the length which
it occupies in the bore by means of the graduated brass scale set in the rammer-staff for that purpose;
insert the shot, ram it home and measure in the same manner the height of the whole charge prick
the cartridge, and prime with a tube having a short piece of quick-match inserted in the cup, in order
to give time for withdrawing the linstock before the gun recoils. A quill or paper tube is preferable
for priming with, as the metal tubes are driven with considerable force against the sides, or the roof, of
the shed.
Wipe the graduated are and adjust the index of the pendulum as before, taking care that the nuts on
the screw-bolt are set firmly against the adjusting weights.
Before giving the order to fire, be sure that both pendulums are at rest and in their true positions.
After the discharge, note the arc of recoil.
Two men stop the vibrations of the pendulum by throwing a rope over the breech of the gun against
the suspension-frame; in this manner they are less apt to twist the frame than when acting directly
with the bands against the gun. Clean out the gun and prepare for another charge. During the firings
the pendulums should be carefully observed, to see if any derangement occurs in the position of the
shafts in their V's, or in the stability of the frames, the tightness of the nuts, dec.
Formula for computing the velocity of the ball from the recoil of the pendulums.-1. By the ballistic
pendulum.-The formula for the velocity with which the ball strikes the pendulum block is
bi
where V is the required velocity of the ball in a second;
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p the weight of the pendulum;
g the distance of its centre of gravity
o the distance of its centre of oscillation
}
from the axis of
i the distance of the point of impact
motion;
b the weight of the ball;
A the angle of first vibration of the pendulum;
G the measure of the force of gravity, = 32-155 ft., at Washington.
The demonstration of the correctness of this formula is given in Hutton's Mathematical Tracts.
In our pendulums the axis of the gun and that of the pendulum-block are adjusted on the same hori-
zontal line, when the pendulums are at rest; therefore the ball strikes very near to the axis of the
block, and in order to prevent any shock on the axis of suspension, the centre of oscillation of the system
is made to coincide also very nearly with the axis of the pendulum-block, and this adjustment is main-
tained by renewing the core of the block and restoring the pendulum after each shot to its original con-
dition; hence the values of o and i in the above formula are very nearly equal, and the quantity Pg
being very great in comparison with bi, no sensible error will be caused by assuming i = o in the first
term under the radical sign; the formula then becomes
sin.
Moreover, in practice with balls of the same kind and calibre, the variations in the value of b are
confined within narrow limits. On this account, and in consideration of the great inequality between
the terms pg and b i, we may, in the case just mentioned, assign to bi, in the numerator of the above
expression, a constant value equal to the mean weight of the balls multiplied by the mean distances of
the points struck from the axis of suspension. By this assumption the whole term
becomes constant for one set of experiments, and the formula is perfectly adapted to logarithmic com-
putation.
In making the calculations of the velocity for a case of extreme variation in the value of bi, it was
found that the error produced by the above transformation of the formula, and by assuming a constant
mean value for P + bi, is so small that it may safely be disregarded.
Since 2 sin. = chord of A, it is obvious from the formula, that, all other circumstances being
equal, the velocity of the ball is proportional to the chord of the arc of vibration of the pendulum.
2. Computation of the velocity of the ball by the recoil of the gun pendulum.-The formula for this
purpose is taken from the Report of experiments on gunpowder at Metz. The formula is,
2 sin. c N
; in which
w' is the required initial velocity of the ball;
p' the weight of the gun pendulum;
g' the distance of its centre of gravity
i' the distance of the axis of the gun
}
from the axis of
o' the distance of its centre of oscillation
suspension;
A' the angle of vibration of the pendulum;
b' the weight of the ball and wad;
D the diameter of the bore of the gun;
d the diameter of the ball;
c the weight of the charge of powder;
c' the weight of the cartridge, including the bag;
G the force of gravity, = 32.155 ft.;
N a constant factor, of the same kind as g', G, &c., to be determined by experiment.
There are obvious causes of error and uncertainty which may prevent the results of this calculation
of the velocity from coinciding in all cases with those obtained by means of the ballistic pendulum, even
after allowance is made for the loss of velocity occasioned by the resistance of the air whilst the ball is
passing from the gun to the pendulum-block. The principal one of these causes is the uncertainty of
the value t v', assumed for the mean velocity of the inflamed gunpowder in the bore of the gun. It is
certain also that a considerable portion of the elastic fluid escapes through the windage of the ball, and
therefore the mass of fluid behind the ball is less than that of the charge of powder; but this loss of
fluid is in some measure compensated by the greater velocity of the part which passes by the ball.
The effect now under consideration must likewise be modified by the quality of the gunpowder and the
quantity of the charge, even within the usual limits of practice, and these circumstances probably exert
a still greater influence on the value of the quantity N in the term c N. Capt. Mordecai found that the
results of his experiments with the 32-pounder and 24-pounder guns were well represented by giving to
N a mean value of 1600 feet. This value of N does not appear to apply equally well to the computation
of the velocities of balls of very small calibre; for the intensity of the heat, and consequently the elastic
force of the fluid, generated by the combustion of the charge, increase in a greater proportion than the
direct ratio of the quantity of powder, and the value of N must therefore vary with the charge of
powder, and also with the length and calibre of the gun and the density of the ball. However, as in
ordinary practice with the cannon pendulum, the variations in the value of N cannot be great, and as
the quantity c N is much smaller in value than the other term in the numerator of the formula for the
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velocity, no considerable error arises from assigning to that coefficient a constant mean value, as above
stated.
Manner of loading the gun.-Of the balls-The shot and shells used in these experiments were of an
intermediate gage between the large and the small gage, c. g.:
For the 32-pounder gun, between 6-235 in. and 6.27 in. and for the 24-pounder gun, between 5-66
in. and 5.70 in.
With the exception of some of the first 32-pounder shot, those used in the experiments were ham-
mered shot. Each shot was floated in mercury, and the upper extremity of the axis passing through
its centre of gravity was marked with a centre-punch. For the sake of brevity, the axis of the ball
which passes through the centre of gravity will be designated as the principal axis.
Of the wads-The wads ordinarily used in the experiments are grommets, or rings formed of a single
strand of packing yarn, about t inch thick, such as is used for the packing of pistons in machinery this
yarn is soft and very slightly twisted. The diameter of the grommet is a little less than that of the
ball, to which it is attached by four leather straps about 1 inch wide, each pair crossing the other at
right angles, and being tied on the ball with twine strings; the grommet has also a cross of twine to
assist in placing it and to preserve its form. The thickness of the leather straps is nearly equal to half
the windage of the ball. The average weight of a grommet with straps is, for the 32-pounder ball,
0·1 lb.; for the 24-pounder, 0.08 lb.
The grommet is placed on the lighter hemisphere of the ball, in a direction perpendicular to its prin-
cipal axis.
Of the cartridges.-The cartridge-bags are made of closely woven twilled woollen stuff; they are cut
with a circular bottom like those for field service, and sewed on a cylindrical former of the regulation
size, the diameter of the former being for the 32-pounder gun 5-9 in., and for the 24-pounder 5.85 in.
Of the manner of loading.-The cartridge being inserted, is pressed firmly with the rammer against
the bottom of the bore, and its height measured. The ball is then placed with one of the leather straps
resting on the lower side of the bore, the grommet outside, 80 that the heavier hemisphere of the ball
is next to the powder. The leather straps not only retain the grommet, but also support the ball
nearly in the centre of the bore.
In order to prevent the ball from being detached from the grommet, it was pushed to its place with
the end of the rammer-staff, which caused it to slide on the bottom of the bore instead of rolling; the
rammer being then turned, the height of the whole charge is measured. The difference between the
height of the cartridge and that of the whole charge is less than the diameter of the ball, because the
centre of the ball lies above the neck of the cartridge, and consequently the bottom of the ball passes
beyond the tie of the cartridge and rests against the powder.
After the discharge the gun is cleaned with a cylindrical brush made of stiff bristles, and then wiped
out with a common woollen sponge. The gun is washed after each series of rounds with the same
powder, (generally after 3 rounds,) and is then wiped with a dry sponge.
The muskct pendulum.-The frame for supporting the musket-barrel consists of two parallel bare of
iron, connected together by a transom at each end; each of these bars has an ear coutaining a trunnion-
hole to receive the trunnions of the musket-barrel, which are fitted into a solid cylinder of iron that is
substituted for the breech-screw of the musket; the barrel is held in its place and adjusted by means
of four set-screws passing horizontally through the bars of the frame, one pair near each end of it; a
fifth set-screw, passing vertically through the front transom, serves to adjust the musket-barrel in a
horizontal position when the frame is horizontal
This frame is suspended by means of four iron rods, Fig. 2232; at the lower end of each rod is a
shackle which is bolted to the transoms of the barrel-frame, and a similar shackle serves to connect the
rods above with the shaft of the pendulum; the screws cut in the ends of each rod, to unite it with the
shackles, are right and left hand screws respectively, 80 that by turning the rod, the distance of the
frame from the shaft is increased or diminished at pleasure, and in this manner the height of the axis of
the barrel is readily adjusted when once adjusted, the rods are held fast by nuts screwed up against
the shackles, to prevent the rods from turning.
The shaft of the pendulum is a flat bar of steel, at each end of which is a knife-edge well hardened
and tempered.
The parts of this pendulum are 80 arranged that, when it is at rest, the frame is nearly horizontal;
the slight adjustment requisite for making it exactly horizontal is effected by means of leaden weights,
supported by a small bolt screwed into the rear transom of the frame; a thumb-screw nut serves to
keep these weights in place, by pressing them up against the transom.
The knife-edges of the shaft rest in V's of hardened steel, which are set in cast-iron hangers connected
by a plate, and this plate is secured by four bolts to another plate, also of cast-iron, which is firmly
bolted and braced to a brick wall.
The arc of vibration is measured on a brass limb, which is clamped to an iron plate, on which it can
slide in a circular direction, 80 that the zero of the limb may be properly adjusted; the iron plate is
supported by a frame of wrought-iron secured to the wall, and furnished with four set-screws which
serve to adjust the arc to the proper distance from the knife-edges; a slider moves in a groove in the
brass limb, and is retained at any part of the limb by the pressure of a slight spring. In the vibration
of the pendulum the slider is moved by an index attached to a bar which is fastened, at a suitable
height, to two of the rods of the pendulum-frame.
The radius of the graduated arc is 573 inches: each degree of the brass limb is divided into six
parts, and the vernier on the slider subdivides these parts into minutes.
The ballistic pendulum.-This pendulum is composed of a hollow conical block of bronze, suspended
by two iron straps to a shaft formed of a flat bar of steel, with knife-edges like those of the musket
pendulum; a brace between the straps serves to stiffen them, and into one end of this brace is screwed
the index which moves the slider on the brass limb for measuring the vibration of the pendulum.
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An iron clamp, of a simple construction, presses a circular wooden plate against the face of the pen-
dulum, Fig. 2233, and the point struck by the ball is marked by the perforation of this wooden plate.
The core of the pendulum-block consists of, 1st. A block of hard wood, turned to fit the bottom part
of the pendulum-block.
2d. A conical block of lead, faced with a plate of iron, occupying nearly the centre of the core.
3d. A block of hard wood, turned and cut to such a length as just to fill the pendulum-block, and to
bear against the face-plate.
These blocks were made of well-seasoned hickory, accurately adjusted to the proper weight by boring
holes in them, which were, when necessary, filled with plugs of lead. This weight is such as to keep
the axis of the block horizontal when the pendulum is at rest.
The wooden face-plate was used for many rounds, the balls always striking in a hole one inch in
diameter, in the centre of the plate.
2233.
2234.
The arrangements for suspending the ballistic pendulum and for measuring the vibration are the
same as those for the musket pendulum. The distance between the axes of the two pendulums is ten
feet; the muszle of the musket is six feet from the face of the pendulum-block.
A screen of boards, having a hole two inches in diameter for the passage of the ball, is placed two feet
in front of the ballistic pendulum, to intercept the wads and the blast of the charge.
The pendulums are attached to the south side of a brick wall, and covered by a wooden shed.
Service of the pendulums.-After numerous experiments on the manner of londing the musket-barrel,
it was determined to adopt nearly the same method that is pursued in ordinary service.
The charges are weighed with an accurate balance and put into small tin canisters: to load the piece,
the charge is poured into a small copper or tin charger attached to the end of a ramrod the musket-
barrel is inverted over it, the vent being previously stopped with a brass wire; the barrel and charger
are then again reversed together, and the charge of powder is shaken out into the bottom of the barrel.
The ball is wrapped, as for a common cartridge, in a rectangle of ball-cartridge paper, 3 in. X 45;
the paper is choked tight over the ball, and also slightly choked below, to prevent the ball from falling
out. Instead of merely inserting the hall, with the paper, over the powder, the paper is first formed
into a wad, in a manner nearly uniform, by putting the cartridge-case, with the paper down, into a piece
of musket-barrel, and pressing on the ball with a wooden rammer, which crumples the paper neatly
into a sort of sabot. In loading, the paper is inserted next to the powder; the ball is followed up with
the rammer, which is of steel, and weighs 11 pounds; this rammer is then raised six inches and let fall
on the charge once the height of the charge was always measured by a graduation on the rammer, in
order to guard against error in loading.
The balls were prepared by means of dies, adapted to an ordinary punching machine, and were made
very nearly exact in size, form, and weight.
After each discharge, the musket-barrel is taken from its frame, and wiped carefully with dry rags;
it is washed generally after five rounds.
The set-screws on one side of the frame being undisturbed, the direction of the barrel requires no
other adjustment, after being once set, than to be pressed up gently, but firmly, by means of the screws
on the other side of the frame.
The charge is fired with a piece of quick-match in the vent.
The wooden block into which the ball is fired is 45 inches long; with a charge of even 100 grains the
musket-ball generally penetrates through this block, (of hickory wood,) and is flattened against the iron
plate with which the lead block is faced; the lead and the wooden core are usually wedged slightly
against the sides of the block, and have to be driven out through a hole left in the bottom of the
pendulum-block for that purpose.
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GUNPOWDER.
Elements for computing the velocity of the ball.-The formulse for this purpose are the same as those
before given for the large pendulums.
The constant elements of the calculations, in the usual condition of the pendulums, are as follows:
1. For the Ballistic Pendulum.
Total weight of pendulum
P = 55 lbs.
Distance of centre of gravity from knife-edges
g = 614 in.
Time of 1000 oscillations
1379 seconds.
Distance of centre of oscillation from knife-edges
o = 74354
Force of gravity
G = 38586
Distance of the axis of the block, or usual point of impact,
from the knife-edges
i = 79. in.
Weight of the ball of 0.64 inches diameter
b = 0.05679 lbs.
do.
do.
0.65
do.
= 0.05861
Log. V(pg + bi)(pgo+bi) { for ball 0.64 in
= 43279424
12bi
for ball 0.65 in
= 43142795
The variations in the point of impact being very small, its distance has been regarded as constant, in
the decominator as well as in the numerator of the formula; but in case of any considerable variation
the correction is easily made in the above logarithms, by adding or subtracting, as the case may be, the
difference between the logarithm of 79 and that of the true value of i.
2. For the Musket Pendulum.
Total weight of pendulum
= 88.94 lbs.
Distance of centre of gravity from knife-edges
g' = 43.85 in.
Time of 1000 oscillations
1297 seconds.
Distance of centre of oscillation from knife-edges
o' = 65.77
Force of gravity
G = 385.86
Distance of axis of barrel from knife-edges
79.
Log. 12 3.1175821
Mean weight of the rectangle of cartridge paper, (3 in. X 45 in.)
in which the ball is wrapped
10-5 gra.
Diameter of the bore of the musket-barrel
069 in.
No value that can be assigned to the quantity N in the formula will produce results of equal accu-
racy when applied to different kinds of gunpowder, and in all cases it appears that the value of N is
much smaller for the musket than for the cannon pendulum. This would appear to be the natural con-
sequence of variations in the force or intensity of the flame produced by the combustion of various kinds
of powder; that powder which acts with the greatest force on the ball whilst it is near the bottom of
the musket-barrel, having been more thoroughly consumed at the first moment of ignition, will probably
have a smaller proportional expansive force remaining, after the ball has left the barrel, than the pow-
der, which, burning with less energy at first, continues to develop its force as the ball passes through the
barrel; and this difference of effect becomes greater in proportion as the length of the barrel is increased,
and the absolute quantity of powder in the charge diminished.
The apparatus for closing the vent was suggested by that proposed for Mr. Colson's eprouvette, in
the fourth number of the Mémorial de Artillerie."
The apparatus is represented in Figs. 2234 and 2235 it consists of a block of wrought-iron, hollowed
out on the under part to fit the gun, and having a small hole through it to correspond with the vent of
the gun when the block is in place; this block is bored longitudinally,
2234.
to receive a hollow conical plug of cast-steel, which is ground to fit tight
in its place when pushed down to the bottom of the bore in the block;
the plug has also a transverse hole, or vent, through it, which corresponds
with that in the block when the plug is drawn out about 0.4 inches from
the bottom of its lodgment in the block, 80 that, in that position, there
is a direct communication open with the bore of the gun. The hollow
plug is charged with a small quantity of fine, quick (sporting) powder,
over which a paper wad is rammed; it is then placed in the position
above described, and the charge is fired by means of a small piece of
quick-match inserted in the upper part of the vent in the iron block; the
2235.
charge in the gun is ignited with certainty, although there is no priming
in the proper vent of the piece; but before the explosion of the charge,
the conical plug has recoiled to the bottom of its lodgment, and effectu-
ally closed the vent.
After the discharge the plug is again driven out, through a hole made
for the purpose in the bottom of the iron block; the plug should be fitted
80 as to bear against the bottom at nearly the same time that it becomes
wedged in its seat, otherwise too great a force is required to drive it out;
on the other hand, if the plug touches the bottom before it binds on the sides, it will fly out again, and
not produce the desired effect.
Conclusions-The following are some of the practical conclusions which Capt. Mordecai has arrived
at by his experiments at the Washington Arsenal.
With regard to the proof of gunpowder.-The only reliable mode of proving the strength of gunpow
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der is to test it, with service charges, in the arms for which it is designed; for which purpose the
ballistic pendulums are perfectly adapted.
Although the present tendency to the use of cannon of very large calibre would make the proof by
means of a 32-pounder or 24-pounder gun more satisfactory than by using a piece of smaller calibre, it
does not seem to be necessary to resort to those heavy guns for obtaining a correct indication of the
relative force of different kinds of powder. Such an indication is not given by a 1-pounder gun; but
the experiments at Metz have shown that the 12-pounder gun classes the powders in the same order of
strength as the 24-pounder; and further experiments may, perhaps, prove that a long gun of yet smaller
calibre, a 9-pounder or a 6-pounder, will give corresponding results. I should propose, for the usual
proof of gunpowder, to make use of the cannon pendulum alone; employing a gun of the smallest cal-
ibre which will give correct results, and firing the balls into a bank of earth, which would not make
them unfit for ordinary service.
In the 24-pounder gun, new cannon powder should give, with a charge of 4th, an initial velocity of not
less than 1600 feet to a ball of medium weight and windage.
For the proof of powder for small arms, the small ballistic pendulum is a simple, convenient, and
accurate instrument. The cost of the apparatus might be reduced by dispensing, in most cases, with
the musket pendulum, and simply firing the ball into the ballistic pendulum-block, from a barrel set in
a permanent frame.
The initial velocity of the musket-ball, of 0-05 inches windage, with a charge of 120 grains, should be
With new musket powder, not less than 1500 feet
With new rifle powder, not less than 1600 feet;
With fine sporting powder, not less than 1800 feet.
The common eprouvettes are of no value as instruments for determining the relative force of different
kinds of gunpowder.
Of the hygrometric test of gunpowder.-Although the projectile force of gunpowder is the most im-
portant quality to be attended to in the proof and inspection, its capability of being long preserved
without much deterioration, and of resisting the effects of such exposure as it is subject to in service,
must be regarded as of little less importance. This quality should, therefore, be tested either by com-
paring the quantity of moisture absorbed, under similar circumstances, by the powder which may be
under trial, and by other powder of approved good quality, or by the application of a simple chemical
test of the purity of the saltpetre, as it is on this circumstance chiefly that the capacity of the powder
to resist the action of a moderate degree of moisture depends.
Of the proportions of the ingredients of gunpowder.-The proportions used in making our best pow-
der, 76-14-10, and the English proportions, 75-15-10, appear to be favorable to the strength of
powder, and not sensibly disadvantageous in other respects; but the ordinary variations in the propor-
tions of cannon powder are scarcely appreciable by their effects on its force.
Of the mode of manufacture.-The powder of greatest force, whether for cannon or small arms, is
produced by incorporation in the cylinder mills," under heavy rollers. In this manufacture, the essen-
tial operations are the separate pulverization of the materials, their incorporation by the cylinder mills
alone, and the formation into cake by moderate pressure, on thick cakes. The time of running the mills
on a given charge must depend partly on the weight of the rollers; but the diminution of this time by
means of previous mixture of the ingredients for several hours, in the dust-barrels, appears to impart to
the powder a degree of density which, although attended, perhaps, with somewhat increased force in
the cannon, is injurious to other valuable qualities of the powder, and especially to its capability of
resisting the effects of exposure to moisture.
The pounding mill is capable of producing powder of nearly equal force to the cylinder-mill powder,
but for that purpose it must be worked not less than 14 or 16 hours, and even then, unless it is pressed,
the grain is hardly sufficiently firm to bear, without injury, the jolting of ammunition wagons.
Of the density of gunpowder.-The density should not be less than 850; it is not easy, and perhaps
not necessary, to establish an absolute maximum of density, on account of the differences caused by
accidental variations in the size and form of the grains; but it does not appear necessary or advisable
that the gravimetric density should exceed 920.
Of the sizes of grain for gunpowder.-If it should not be deemed incompatible with the convenience
of service to multiply the varieties of powder for special purposes, there would probably be an advan-
tage in using very large-grained powder (such as that designated by A. 0) for 18-inch mortars, and for
the heavy sea-const howitzers, in which enormous charges of powder are used. By this means the strain
on the gun would be diminished, and the velocity of the ball perhaps increased.
For musket powder, by the present standard gages-
All the grains should pass through No. 4;
About one-half through No. 5;
Nearly one-fourth through No. 6.
This would give about 2000 or 2500 grains of powder in 10 grains Troy.
For rifle powder, all the grains should pass through No. 6. There would then be about 12,000 or
15,000 grains of powder in 10 grains Troy.
Of the charges for cannon and small arms.-For cannon, the charge of fth the weight of the ball,
with powder of the standard strength proposed, impresses on the ball a sufficient velocity for all the
ordinary purposes of service. For any purpose, even for a breaching battery, the advantage gained by
using a charge greater than dd the weight of the ball is unimportant, and by no means compensates for
the inconvenient recoil, and the destructive strain on the gun and carriage, dic.
But as the habitual charge in the French and other services is d, and the battering charge t the
weight of the ball, it may be well to compare the effects of these charges of French powder with that
of the charges which Capt. Mordecai proposes to substitute for them. For this comparison a glance at
the following table will suffice.
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GUNTER'S CHAIN.
The French 30-pounder corresponds very nearly, in diameter and length of bore, with our 82-pounder.
The windage of the balls used in the French experiments is somewhat greater than that of the balls
used in Capt. M.'s experiments, but the difference is not very important.
Calibre of
Place of experiment.
Kind of powder.
Charge.
Velocity of ball
Remarks.
gun.
at the pendulum.
Feet.
Esquerdes
80-pound.
French pounding mill
1513
Mean with 4 kinds of
Washington
a.
1535
Arsenal
32-pound.
A.
Cylinder mill
powder.
1611
Esquerdes
24-pound.
French pounding
1677
Mean of 40 rounds,
Metz
"
mill, 11 hours
1575
with 2 kinds powder.
Washington
1570
as
a.
Powd. made at Mets,
Arsenal
A.
1687
1836.
Metz
24-pound.
French pounding mill
1772
Ditto.
Washington
"
A.
1833
For small arms the following charges are proposed:
For the percussion musket. with the proposed musket powder, 110 grains.
For the percussion rifle, 75 grains.
For the percussion pistol, 30 grains of rifle powder.
Of cartridges for cannon.-For the purpose of diminishing the strain on the gun, Capt. M. proposes
that the principle of increasing the length of the cartridge, by reducing its diameter, should be adopted
for heavy guns. The diameters of the cartridge formers may be established as follows:
Calibre
42
32
24
18
Diameter of cartridge former
Inches
6.
5.5
5.
46
Of the loss of force by windage.-Bring the results into one view, as in the following table:
Powder of one
Ball.
Differences.
Ratio of difference.
Calibre of
kind.
gun.
Weight.
Windage.
Velocity.
Of windage.
Of velocity.
Of windage.
Of velocity.
Lbs.
Inch.
Feet.
Inch.
Feet.
24-pound.
"
0.007
1578
"
of
-115
1459
0.108
119
"
"
-245
1332
238
246
2.28
207
"
"
355
1197
348
381
3-22
3.20
"
6
-115
1749
as
"
245
1596
0-13
153
06
"
355
1465
.24
284
185
186
By taking the difference between the first windage and each of the others, in each set of experiments,
and the corresponding differences of velocity, and then dividing each of these differences by the first of
its series, we obtain the ratios between the several differences of windage, and between the correspond-
ing differences of velocity. These ratios approach 80 nearly to equality as to authorize the conclusion
that the differences in the velocities of balls of different diameters are proportional to the differences of
windage; or, in other words, that the loss of velocity by windage is proportional to the windage.
Of the loss of force by the vent of the gun.-The loss of velocity in consequence of the escape of gas
through the vent of a cannon is inappreciable, in comparison with the unavoidable variations produced
by other causes: 80 far as this effect is concerned, it would be nearly useless to close the vent in firing
the gun.
Of the effect of wads.-In the service of cannon, heavy wads over the ball are, in all respects, inju-
rious. For the purpose of retaining the ball in its place, light grommets should be substituted for junk
or hay wads, and the latter should be used only for proving guns, for firing hot shot, or for saving the
bore of the gun from injury by placing them between the powder and ball, in order to change the seat
of the ball, from time to time, and prevent the formation of a lodgment.
In small arms, on the other hand, it is of great importance, for developing the full force of the charge,
that there should be a good wad over the powder, unless the ball has but very little windage, as in
the rifle.
GUNTER'S CHAIN, 80 called from its reputed inventor, is the chain commonly used for measuring
land. It is 66 feet or 4 poles in length, and is divided into 100 links, each of which is joined to the
adjacent one by three rings; and the length of each link, including the connecting rings, is 792 inches
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GUTTA PERCHA.
941
The advantage of this measure consists in the facility which it affords to numerical calculation. The
English acre contains 4840 square yards; and Gunter's chain being 22 yards in length, the square of
which is 484, it follows that a square chain is exactly the tenth part of an acre. A square chain again
contains 10,000 square links, 80 that 100,000 square links are equal to an acre; consequently, the con-
tents of a field being cast up in square links, it is only necessary to divide by 100,000, or to cut off the
last five figures, to obtain the contents expressed in acres.
GUNTER'S LINE. A logarithmic line engraved on scales, sectors, &c, serving to perform the mul-
tiplication and division of numbers instrumentally, as a table of logarithms does arithmetically. The
numbers are usually drawn on two separate rulers aliding against each other. In rough calculations
this line affords considerable facilities.
GUNTER'S SCALE is a large plain scale, having various lines of numbers engraved on it, by means
of which questions in navigation are resolved with the aid of a pair of compasses. On one side of the
scale the natural lines (as the line of chords, the line of sines, tangents, rhombs, dc.) are placed, on the
other the corresponding logarithmic ones.
GUTTA PERCHA, or, more properly, Gutta Tuban, is the concrete juice of a tropical tree, and is
drawn, at certain seasons of the year, like the sap of the sugar-maple, by tapping the tree.
The mode in which the natives obtain the gutta is by cutting down the trees of full growth and ring-
ing the bark at distances of about twelve to eighteen inches apart, and placing a cocoanut-shell, spathe
of a palm, or such like receptacle, under the fallen trunk to receive the milky sap that immediately
exudes upon every fresh incision. This sap is collected in bamboos, taken to their houses, and boiled
in order to drive off the watery particles and inspissate it to the consistence it finally assumes. Al-
though the process of boiling appears necessary when the gutta is collected in large quantity, if a tree
be freshly wounded, a small quantity allowed to exude, and it be collected and moulded in the hand,
it will consolidate perfectly in a few minutes, and have all the appearance of the prepared article.
When it is quite pure the color is of a grayish white, but as brought to market it is more ordinarily
found of a reddish hue, arising from chips of bark that fall into the sap in the act of making the inci-
sions, and which yield their color to it. The great peculiarity of this substance, and that which makes
it 80 eminently useful for many purposes, is the effect of boiling water upon it. When immersed for a
few minutes in water above 150° Fah., it becomes soft and plastic, so as to be capable of being moulded
to any required shape or form, which it retains upon cooling, and regains its original toughness and
flexibility.
The gutta percha is soluble, but not by the same agents as India-rubber. The fixed oils are all
unctuous substances, and acids have no influence upon it. This property renders it very valuable for
purposes of machinery, where, when used for driving-bands, as it is most extensively, it is constantly
brought in contact with oils and grease.
Gutta percha may be manufactured by moulding, stamping, embossing, casting, or any other known
process or processes, into various articles of use; as glass and picture frames, cornices, mouldings, and
other architectural ornaments, panelling, mosaics, &c.;" in a word, it may be worked into any form, and
almost any color may be given, from the simplest to the most complex. Cornices of the most elaborate
designs, in imitation of several kinds of wood, are manufactured of it; and from the toughness of the
material, even the most delicate representations of foliage are not liable to injury. Copies of old oak
panelling taken in the gutta percha, have preserved every trace of the original; the grain of the wood,
its abrasion by age, its color and pattern, and all with the utmost fidelity. Impressions taken from
coins and medallions are really beautiful; and statues may be copied by it with great truth and at a
comparatively small cost.
Its capabilities of application to 80 many of the staple articles of our country, aside from its employ-
ment in the department of the ornamental arts, gives to its manufacture an almost boundless extent.
Something may be judged of the truth of this statement by running the eye over the following list of
articles, which by no means exhausts the range of gutta percha:
Machine belts and bands; gas-pipes and water-pipes; speaking-pipes; the insulating of telegraph
wires; saddles and harness of all kinds; trays, fancy boxes, tables, pumps, boxes, and valves; book-
binding, vellum, balls, water-proof roofing, inkstands, drinking-cups, canes, whips, flasks, hate, caps,
boots, shoes, clothing; decorations for houses and ship-cabins; chairs; lining for bread casks for sea
voyages; air-tight coffins; linings for water-tanks; powder kegs, for the transportation of powder in
water soda fountains, gasometers, bottles, pictures, and looking-glass frames.
It also recommends itself to the attention of the medical faculty; and as scientific persons give the
subject the attention that humanity demands, it will be found to possess valuable properties, superior
for many purposes to any other substance. It has already been approved for bougies, catheters, stetho-
scopes, nipple-shells, handages, and splints. This latter article is invaluable from the facility with which
it adapts itself, when made plastic in boiling water, to the form of the limb; for preserving the strength
of medicines of a volatile nature, and in the application of galvanism or electricity to the healing art, it
can be made a valuable agent, being a perfect non-conductor. For marine and national purposes, the
field is most extensive; as an inside sheathing for ships, for buoys, and beacons, it is supposed to resist
for all time the vermin that is 80 destructive in southern waters. Army and navy equipments, canvas,
deck-covers, car-covers, sails, and rigging, are rendered impervious to water and dampness, preventing
mildew and rot. It is of a light color, and not injured by climate or a tropical sun. For cannon-covers,
water-tanks, life-boats, and many other applications, it is destined to supersede metal and India-rubber.
It will also be found superior to glue in its adhesive properties, and to the gums generally, as a basis
for various varnishes, sizings and paints, being weather-proof and not liable to crack.
Gutta percha is a perfect non-conductor of electricity, and, as above stated, is used for the insulating
of telegraph wires; in Prussia the wires are covered with the gutta and embedded in the earth, and
afford by far the best and surest means of preserving telegraphic communication.
Various experiments have been made to ascertain its strength when mixed with other matters and
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GUTTA PERCHA.
also as to what pigments would mix with it without rendering it brittle or deteriorating its qualities.
From these it appeared that the only pigments that could altogether be relied on to be used with gutta
percha, were orange lead, rose pink, red-lead, vermilion, Dutch pink, yellow ochre, and orange chrome.
Under the influence of heat and pressure, gutta percha would spread to a certain extent, and more so
if mixed with foreign matters. All the mixtures composed of gutta percha and other substances which
had been subjected to experiment, except that containing plumbago, were found to increase its power
of conducting heat; but in its pure state gutta percha was an excellent non-conductor of electricity.
The best composition for increasing the pliability of gutta percha was that formed in conjunction with
caoutchouc tar, and next in order that of its own tar; and the best material at present known for
moulding and embodying was obtained by mixing gutta percha with its own tar and lamp-black. Dri-
ving-bands for machinery are thus made, and shoe soles and heels are stamped out of similar sheets of
gutta percha. In making tubes or pipes of gutta percha or any of its compounds, a mass of gutta per-
cha, after being thoroughly masticated, is placed in a metal cylinder furnished with a similar piston, by
which it is pressed down into an air-box, kept hot with steam, which has at its lower end a number of
perforations, through which the plastic material is forced into a cup, whence it passes out, round a core,
into the desired tubular form, and thence through a gage to the required size, and into a receiver of
cold water, being drawn to the other end of a long trough by a cord passing round a pulley at the far
end of the trough, and returning to the person in attendance on the machine, who gradually draws the
pipe away from the air machine. Thus tubes of considerable length and diameter are made to a very
great extent, and are used for the conveyance of water, liquids, and gas.
The machinery for working the crude gutta percha is constructed and worked as follows:
Fig. 2236 is a side elevation of the slicing machine; Fig. 2237 a front elevation of it; and Fig. 2238
a sectional elevation A on the line a b of Fig. 2237.
A A represents the frame-work; B is a circular iron plate, of about five feet diameter, in which are
three slots, into which are inserted three radial knives, in a similar manner to the irons of an ordinary
plane or spoke-shave. Bª is a shaft, to the end of which the plate B is attached, and by means of
which it is made to revolve at any desired velocity, motion being communicated to the shaft from a
steam-engine, or any other convenient first mover, through the medium of geering or drums. D is an
inclined shoot, down which the lumps of crude gutta percha are dropped against the knives of the re-
volving plate B, by which they are cut into slices of a thickness corresponding to the degree of projec-
tion given to the knives. The slices are afterwards collected, and put into a vessel filled with hot
water, where they are left to soak till they feel soft and pliable to the touch.
2237.
2236.
2238.
(i
D
B
D
B
A
A
22
The knives are represented in the drawings as being straight; but where the gutta percha to be cut
happens to be of a more than usually hard or intractable quality, it is advantageous to substitute knives
of a curved or reaping-hook form, on account of their more gradual mode of action.
Fig. 2239 is a longitudinal elevation in section of the machinery through which the gutta percha is
passed, after having been steeped as aforesaid in the hot-water vessel till it has become soft and pliable
to the touch. T is a large tank, which is divided into three compartments tet, of which t1 and tª are
filled with water to the height of the line xy, and ts with water to the height of the line x 2. FFF
are three breakers or rollers, with serrated blades inserted in them in a direction parallel to their length,
which are mounted transversely over the tank T, and revolve clear of the water. In front of each of
these breakers there is a pair of fluted feeding-rollers G' G'. H' is a funnel-shaped shoot. through
which the softened pieces of gutta percha, after being taken from the hot-water vessel, are passed to
the feeding rollers G1 of the first breaker F1. H' is an inclined endless web, which revolves on two
rollers a a, and dips at its lower end into the water, while at its upper end it comes opposite the space
between the feeding-rollers of the breaker F2. H' is a second inclined endless web, which bears the
same relation to the third breaker FS as H' to F. K is a mincing cylinder, with radial blades (similar
to that used in paper-mills for the conversion of rags into pulp) which is mounted transversely over the
third compartment t³ of the tank, but at a lower elevation than the breakers F¹ F' Fᵃ, so that one-half
of it shall always be immersed in the water in that compartinent. L is an edge-plate, 80 fixed that
the blades of the cylinder K shall, in revolving, come into such close parallelism with it, as to pro-
duce, by their approximate conjunction, a scissor-like sort of action on any matters which may come in
contact with it. The mincing-cylinder K has, like the breakers F¹ F* F, an endless web H, and a
pair of feeding-rollers G' attached to it. M is a rotary agitator, which is wholly immersed in the water
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GUTTA PERCHA.
948
of the compartment ts. N is a revolving endless web, which stretches in an inclined direction athwart
the whole depth of the water in t3, and subdivides (as it were) the compartment to into two divisions.
R R, R R, are a series of pairs of rollers, mounted transversely over the after part of the compartment
t, at such an elevation that the under rollers revolve under the water, and the upper just free of it.
SS are a series of tables or benches, placed between the pairs of rollers, for the purpose of supporting
the gutta percha in its passage from one to the other.
V
2239.
H
z
The action of this machinery, 80 far as it has been thus described, is as follows:
The feeding-rollers G', the carrying-rollers of the endless webs H2 H' and Hª, and the rollers
R R, are all made to revolve in a forward direction, or from left to right of the machine, as represented
in Fig. 2239, while the breakers F' F'F', the mincing-cylinder K, and agitator M are made to revolve
in the opposite direction. (The mechanical contrivances by which these movements are affected are
omitted from the figure, as being all of a common and well-understood description.) The breakers and
mincing-cylinder should revolve at the rate of from 600 to 800 revolutions a minute, but the feeding-
rollers and endless webs need not move faster than at about a sixth of that rate. The first series of
rollers R R should revolve at the rate of from fifteen to twenty revolutions per minute, and the others
may be made to exert a drawing or stretching effect on the materials passed between them, by causing
one, two, or more of the last pairs in the series to revolve at a greater velocity than the preceding ones.
As the crude gutta percha is presented by the feeding-rollers G' to the action of the first breaker F', it
is broken up into shreds or fragments, and considerable quantities of earthy and other extraneous mat-
ters are beaten out of and disengaged from it, the whole falling in a mingled mass into the water be-
neath, (that, viz. which is contained in the compartment t1 of the tank,) where the different materials
assort themselves according to their specific gravities. Such pieces as consist of pure gutta percha, or
in which gutta percha predominates, float on the surface of the water, while most of the earthy and
other extraneous matters sink to the bottom. The revolving endless web H' then draws towards it the
floating gutta percha, and carries it upwards to the second set of feeding-rollers G', mounted over the
second compartment t of the tank, from which rollers it is delivered to the second breaker F'. to un-
dergo a repetition of the process which has been just described. in order to its being further disentangled
and purified. From the surface of the water in the compartment t, the gutta percha is carried up the
inclined endless web H' to the rollers G, which deliver it to the third breaker F' over the compart-
ment tˢ, by which it is a third time broken up. in order to any remaining impurities being separated
from it. The inclined endless web H' next carries it forward to the rollers G, which present it to the
revolving cylinder K, by the blades of which it is cut or minced into a multitude of very thin alivers,
which, as they fall into the water in t³, are thrown
forward in the direction of the agitator M. As this
agitator revolves in a direction opposite to that in
1
which the floating mass of gutta percha is moving. it
forces the gutta percha down into the water, and to
take a circuitous course through it towards the large
K
endless web N, whereby it is washed free from any
dirt which may have collected upon it in passing
2240.
through the preceding operations. By the endless
web N, the gutta percha is next moved onwards to
the series of rollers R R, R R; and from the last pair
A
G
F
H
of the series, the gutta percha is raised by an endless
a
revolving web o to a pair of metal pressing and fin-
D
ishing rollers Y1 Y', which are set by adjusting
screws to a distance from one another equal to the
L
E
thickness of the sheet or band into which it is now
desired that the gutta percha should be compressed.
F
After passing through between Y'Y', the sheet or
band is carried back over the topmost of these roll-
11
B
ers Y2, and then over the wooden drum U, to be
wound on a taking-up roller V. As it is turning
back over the roller Y'. a sheet of cloth, or any
other material suitable for joining with it, may be led in, as shown at W, and, by being pressed in
conjunction with it between Y2 and the drum U, it will be firmly united to it.
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944
GUTTA PERCHA.
The water in all the compartments of the tank T should be used cold. When the crude gutta percha
happens to have a foetid smell, as is not unfrequently the case, mix with the water a solution of com-
mon soda, or of chloride of lime.
+
8766
2241.
In effecting the combination of sulphur and sulphurets with gutta percha, expose the gutta percha,
after it has been cleansed and purified and reduced to a sheet state, to the combined action of steam of
a high temperature, and the vapors of orpiment (or other volatile sulphuret) and sulphur, (mixed in
the proportions last hereinbefore specified,) in an apparatus of the description represented in Fig. 2240.
A is a strong metallic chamber set in the brick-work BB, into which the materials to be sulphu-
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HAMMER.
945
retted are placed. C is a steam-tight cover or door, which is secured to the top of the chamber by screw
bolts, 80 that it may be unscrewed and removed as occasion may require. D is a common high-pressure
steam-boiler. E is a strong metal pot into which the orpiment, or other sulphuret, and sulpbur are
placed. d a lid or cover through which the materials are introduced; and E' a fireplace by which
the pot is heated. F is a pipe leading from the boiler into the head of the pot E; and a a cock by
which it is opened and closed. G' is a pipe leading from the top of the pot E to the chamber A, and b
a cock by which it is opened and closed. H is a safety-valve attached to the boiler, and K a safety-
valve attached to the chamber A. I is a thermometer to indicate the temperature. The mode of
operating with the apparatus is as follows :-The boiler-furnace is first lighted, and when the safety
valve indicates an approach to a temperature of 280° Fah, the other furnace is lighted which is to
volatilize the orpiment and sulphur. The cocks a and b are then opened, and the steam allowed to
pass off through the pipes F and G, and head of the pot E, into the chamber A, containing the mate-
rial, in order that they may be thoroughly heated before being sulphuretted. After a short time fumes
from the orpiment and sulphur begin to ascend and mingle with the steam. In this state I leave mat-
ters for a period varying from half an hour to two hours, according to the thickness of the materials
operated upon. I then close, by means of the cock b, the passage to the chamber A, draw or damp
the fires, raise the safety-valve K, and when the chamber À has been cleared of vapors, remove the
sulphuretted materials. The safety-valve H is kept, all the time the sulphuretting process is going on,
at a little higher pressure than the safety-valve K, in order that there may be a current in the direction
of the chamber A. L is a cock by which the condensed water, which accumulates in the chamber A,
is drawn off.
The calenders, represented by Figs. 2241 and 2242, as used in the manufacture of driving-bands and
sheets of gutta percha, at the Gutta Percha Works of Brooklyn, New York, have rolls 6 feet 4 inches in
length, and 22 inches in diameter, and each roll will weigh about 7000 pounds. The rolls are heated
by steam.
GYRATION, the centre of, is that point in which, if all the matter contained in a revolving system
were collected, the same angular velocity will be generated in the same time by a given force acting at
any place as would be generated by the same force acting similarly in the body or system itself.
The distance of the centre of gyration from the point of suspension, or the axis of motion, is a mean
proportional between the distances of the centres of oscillation and gravity from the same point or axis.
If S represent the point of suspension, G the place of the centre of gravity, o that of the centre of
oscillation, and R that of the centre of gyration. Then,
SR=VSO.SG
and so. =a constant quantity for the same body and the same plane of vibration.
9943.
HAMMER, ANDERSON'S patent. In this hammer, the claw, as will be seen by
the cut, extends to the handle and clasps it with a strong ring, which makes
it impossible, in drawing nails, for the handle to give way, draw out, or become
loose. The face of the patent hammer will thus always remain true, it being
kept at the same angle with the handle. Six different sizes are now made,
weighing from half a pound to one and a half pounds.
HAMMER, steam. JAMES NASMYTH'S patent steam-hammer. Before pro-
ceeding to describe the principle, mode of action, and constructive details of the
direct-action steam-hammer, it may be proper to make a few remarks on the
ordinary forge-hammers, 80 that the nature of the advantages possessed by the
steam-hammer may be more clearly understood.
In all forge-hammers previously in use, the force necessary to set them into operation had to be
transmitted in a very indirect manner,-for whether a water-wheel or steam-engine were the moving
power, the requisite lifting and falling action of the hammer had to be produced by the employment of
rotatory motion, thus rendering necessary the use of wheels, shafts, cams, and other cumbrous details,
which, together with the apparatus requisite to connect the various parts of the machinery, and give due
strength and solidity to the whole, not only caused great outlay and sacrifice of valuable space, but
also occasioned much loss of power, by reason of the very circuitous manner in which the force of the
prime moving agent had to travel ere it reached its final destination, and came forth in blows from the
forge-hammer. Great inconvenience, also, was found to result from having a considerable portion of the
working machinery close to the hammer, as thereby a very serious impediment was offered to the free
execution of the work. And when we add to this very limited range in the clear fall of an ordinary
forge-hammer, (seldom, in any case, exceeding 18 inches,) causing the force of the blow to decrease in a
very rapid ratio, with a moderate increase in the diameter or depth of the work and when we take
into consideration the fact that, in consequence of the helve of the hammer working on a centre or joint,
its face is parallel to that of the anvil only at one particular distance; and finally, when to this list of
inconveniences we add that in the ordinary forge-hammer we possess no power or control over the force
of its blows, but are compelled to make the best use we can of them, whether they be adapted to our
purpose at the time or otherwise, we find inherent in the very principle of such hammers, a combina-
tion of evils and inconveniences that only excite surprise that they should have been suffered to exist
for so great a length of time.
This remark is most strikingly applicable in the case of those forge-hammers which receive their
power from a steam-engine, inasmuch as the power in question originates in the motion of the piston,
in the very state and condition in which, for the purpose of hammering, we desire it ultimately to be,
namely, as a straight up and down motion; so that instead of causing this reciprocating action of the
piston-rod to pass through all the complex media of beam, connecting-rod, crank and cam shaft, for no
119
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HAMMER.
other purpose than to cause it to act in the same manner as at first,-if we dispense with all this mare
of intermediate machinery, and simply invert the steam cylinder 80 as to bring its piston-rod out at the
bottom of the cylinder, and attach it directly to a block of iron working in guides right over the anvil-
2244.
R
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III.
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face, we shall then have obtained all the grand essentials of a forge-hammer in its simplest and most
obvious, and, at the same time, as experience has demonstrated, in its most perfect and efficient form.
Such is the Direct-Action Steam-Hammer, and such considerations as the preceding led to the inven-
tion of this machine.
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947
Some idea of its efficiency in shingling puddled balls may be formed from the fact, that one of 30
cwt., which has been for nearly two years in constant operation at the Gartness Works of the Monkland
Iron Company, in the West of Scotland, works off with perfect ease the constant produce of from 18 to
20 puddling furnaces. For this duty the steam-hammer is found to be peculiarly adapted, as it can be
made to act for the first few strokes as a squeezer, to bring the puddled ball to a neat cubical form;
after which it may be made to deal out upon it such energetic blows as secures the entire expulsion of
all cinder and other non-metallic impurities, the absence of which, to a greater or less extent, mainly
determines the quality of wrought-iron. In short, in every process where either blows of the most
enormous energy, or slight taps of the utmost gentleness are required, either continuously or in all
grades of variation from the one extreme to the other, the steam-hammer offers facilities which have
never hitherto been obtained from any mechanical contrivance for such purposes.
Fig. 2244 represents a side elevation of the steam-hammer, exhibited in full operation, the hammer-
block, valve-geer, and other working parts being disposed in the positions which they occupy at the
termination of a stroke. Fig. 2245 is a general plan corresponding to the above.
Fig. 2246 is an end elevation, and Fig. 2247 a vertical transverse section of the machine.
Fig. 2248 is a sectional elevation of a portion of the machine, showing the positions of the hammer-
block, valve-geer, and other working parts when the hammer is raised for a fresh stroke.
The framing of the steam-hammer consists of two strong cast-iron standards A A, bolted and further
secured by keys to a broad base-plate BB, embedded in the solid masonry forming part of the floor of
the forge. The standards are surmounted, and their upper extremities united by a species of entabla-
ture C, in which the steam-passages and valve-face are formed, and to the upper surface of which the
steam cylinder D is bolted. The piston-rod E is fitted to work vertically through a stuffing-box in the
centre of this entablature, and its lower extremity is directly attached to the mass of cast-iron F, form-
ing the hammer-block, which is guided to a strictly vertical and rectilinear course by being made to
work freely in planed guides formed on the interior surfaces of the standards A A. The hammer a
itself is inserted into a dovetail recess in the bottom of the block F, where it is retained by wooden
packing and iron wedges; while the anvil b is in a similar manner-secured to the anvil-block G, which
is a mass of cast-iron of such weight as effectually to oppose, by its inertia, the momentum of the ham-
mer, and prevent the force of the blows from being dissipated.
Such are the main features of this machine; from which it will be at once understood that, if we can
provide the means of rapidly raising the hammer-block to a sufficient elevation, and then as rapidly
letting it fall down upon, and 80 give a blow to the work placed upon the anvil, we have all that is
requisite to produce a forge-hammer in its simplest, and, at the same time, its most powerful and per-
fect form.
The duty above adverted to, of raising the hammer-block, is performed by the direct application of
the elastic force of steam. For this purpose, the steam is led on to the machine by the steam-pipe H,
communicating with a neighboring high-pressure boiler; a throttle, or shut-off valve c, inclosed within
the valve-box I, being situated close to its junction with the main steam-valve chest J, and brought
within the control of the attendant workman by means of the rod and lever dd. The alternate admis-
sion of the steam into the cylinder by the port and its escape therefrom by the passage g, and waste
steam-pipe K, are regulated by means of the alide-valve e, which may either be worked by hand, or,
through the intervention of the self-acting mechanism to be hereafter specified, by the action of the
machine itself. The piston L, which is strongly constructed of malleable iron, and fitted with a single
packing ring, works steam-tight within the cylinder D; and being directly attached by the piston-rod
E to the hammer-block F, it will be obvious that, on the admission of steam of sufficient elastic force
beneath the piston, we are supplied with the means of raising the hammer-block to any required height
within the range of the machine; while by opening the communication between the under side of the
piston and the external atmosphere, the action of gravity will be unimpeded, and the hammer will de-
scend upon the work placed on the anvil, and discharge a blow upon it, energetic in proportion to the
weight of the hammer-block, and the height from which it has fallen.
And as, by these simple means, there is no practical inconvenience in supplying the power to raise a
hammer-block of 5 or 6 tons weight to an elevation of 7 or 8 feet above the anvil, some idea may be
formed of the vast energy of the blows given out by such a mass of iron falling rapidly through 80 great
a space, and discharging the whole of its momentum upon the work placed below on the anvil to re-
ceive it. In the case of the old system of forge or helve hammers, about one-third only of the total
weight of the hammer was effective, the other two-thirds resting on the pivot-standards; 80 that, in this
point of view, the proportion between the blow of a steam-hammer and that of a helve-hammer is
nearly 8 to 1 in favor of the former.
It will be seen, further, that the anvil-face and hammer-face are at all times parallel to each other,
whatever be the height or distance between them. The practical value and importance of this prop-
erty, which is inherent in the principle of the steam-hammer, has been duly appreciated by all who
have had experience of the working of this machine.
With a view to prevent any risk of the piston striking the cylinder-cover when working to the full,
or very highest stroke of the hammer, a very simple but effective air or steam recoil spring is provided,
by having the cylinder-cover screwed down quite air-tight, so that as soon as the piston passes, in its
upward motion, the holes hh, the air or steam remaining above is shut up in the upper chamber; and
as it has no means of escape, it acts as a most perfect spring in arresting any further rise of the piston;
and has, besides, the important advantage of converting into increased downward velocity of action the
undue upward action, which might otherwise have proved not only useless, but destructive. The in-
crease of energy in the blows which can be obtained by this simple means is a point of considerable
importance. It is scarcely necessary to remark that, in the emergency above adverted to, the aper-
tures h h act as safety-valves for the issue of the main body of the steam, which escapes through the
passage ii, into the exhaust or waste steam-pipe K.
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948
HAMMER.
2246.
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2248.
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Plan of Fig. 2244 on preceding page.
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HAMMER.
949
Another point of constructive detail worthy of special notice is, the peculiar mode adopted for con-
necting the piston-rod to the hammer-block. This is one of the most important details in the entire
invention, and without which no practical success would have attended it. Had the piston-rod
been attached to the hammer in the ordinary
mode of attaching pistons to the machinery of a
2247.
steam-engine or such like, namely, by a cotter,
or by screwing the rod into the hammer, or such
other solid, unyielding mode, the effect of the
blow or fall, at each stroke of the hammer, would
have been that the piston-rod and piston (being
composed of a considerable mass of materials)
would have themselves acted as a hammer, and
would have discharged their momentum upon
the means of fastening, and this with such de-
structive effect as to break through all such solid,
unyielding means of resistance, after a few blows.
This was foreseen from the first as an action
to be prevented, and accordingly, in my original
drawing, already adverted to, a remedy was pro-
vided, which experience has proved to be entirely
D
effectual.
This contrivance consists in placing, in a cylin-
drical recess formed in the body of the hammer-
block, and under the knob i, on the end of the
J
0
piston-rod, a series of pieces of hard wood, or
other slightly elastic material, as in Fig. 2246.
The effect of this arrangement is to allow the
momentum of the piston and piston-rod to de-
posit itself in such a comparatively gradual man-
"
ner as to cause the concussion arising from the
most severe and energetic blows of the hammer
to have not the slightest evil effects on the piston
and rod; it is, in fact, the very same expedient
0
to which nature has had recourse for the pur-
pose of obviating those unpleasant and destruc-
tive shocks and vibrations which we should ex-
perience at every step or stamp of the foot, had
no cartilage been provided between the joints of
our bones. It is surprising to observe by how
small an amount of elasticity, from the employ-
ment of such compressible material, the evil
effect of violent shocks may be removed. The
connection of the piston-rod and hammer-block
is secured by means of the two keys kk, driven
very firmly above the knob or button j, a layer or
two of the elastic material being interposed for
the purpose of neutralizing any shock in the con-
trary direction.
We shall now proceed to describe the mechan-
ism by which the height of the fall of the ham-
mer, and consequent intensity of the blow, may
be modified according to circumstances, and the
machine made perfectly self-acting.
The requisite alternating motion of the steam-
valve e is produced in the following manner :-
The valve-spindle l is prolonged upwards and
attached to a small solid piston m, working
within a short cylinder M, bolted to the main
steam cylinder D. A small portion of steam is
supplied above the piston m, by a slender copper
tube n, communicating with the steam valve-
chest J; by this arrangement it will be seen
that, unless counteracted by some superior force,
the pressure of the steam upon the piston m will
tend to keep the valve e constantly depressed,
in which position the steam-port f is full open.
This counteracting force is supplied by the action
of the hammer itself; for, by means of the tap-
pet N, (which is bolted to the hammer-block,)
coming into sliding contact, when the latter is
raised, with the small friction-roller o, mounted on the end of a bent lever 00, the screwe I ro I l'.
which is jointed to the opposite end of that lever, is depressed, and that motion being co unrinicate I to
the valve-spindle 1, through the intervention of the connecting-rod Q and valve-lever R. the steam-
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950
HAMMER.
valve e is raised, thus cutting off all further ingress of steam under the piston, and almost at the same
instant permitting the escape of that which had served to raise the hammer. By this simple contri-
vance the upward motion of the hammer is made the agent for its own control in that respect. By com-
paring the relative positions of the parts referred to, as exhibited in Figs. 2244 and 2248, the nature of
the motion above described will be at once most fully understood. To obviate the injurious effects of
the shock of the tappet N against the lever o, a connection is provided at p, on a similar principle to
that formerly described in reference to the connection of the piston-rod and the hammer-block; and in
order to restrict the downward travel of the valve to the proper point, a check or buffer-box S is pro-
vided, consisting of a small cylinder bolted firmly to the framing of the machine, within which a circular
nut, screwed on the lower end of the rod P, works as a piston, a few leather washers being interposed
between the latter and the close or upper end of the cylinder.
It may be here remarked, that it is by no means necessary to continue the admission of steam under
the piston until the termination of the upward stroke, or lift of the hammer, seeing that the velocity
which the hammer-block has acquired in its upward motion makes it continue to ascend after the fur-
ther ingress of the steam has been arrested. This circumstance is a source of considerable economy of
steam, as we have by such action (as well as by that due to the expansive energy of the steam) an
effect as to height of lift of the hammer, greater than that which is due to the actual expenditure of
steam at its original pressure. It is worthy of remark, also, that as the over-running action above
alluded to will necessarily increase in proportion to the velocity of ascent of the bammer-block, this cir-
cumstance will, to a considerable extent, compensate for the increased expenditure of steam due to that
increased velocity.
From the above description it will be obvious, that the lift of the hammer, and consequent intensity
of the blows, depends simply upon the position of the lever o, in relation to that of the hammer-block
when at its lowest point. Therefore, if we can provide the means of altering the distance between
these two points, we shall have it in our power to modify permanently the force of the blows to any
required extent within the range of the machine. This condition is most completely satisfied by the
arrangement of mechanism employed by me, and which is clearly represented in the figures.
The rod P which conveys the action of the lever 0 to the valve-lever R, is screwed throughout the
greater part of its length, and is 80 adjusted in its bearings, as to be susceptible of rotatory as well as
vertical motion. This motion of rotation is imparted to it by means of a handle fixed to a short axis,
working in a bracket T bolted to the framing, and actuating a pair of small bevel-wheels q q. The nut
through which the screw works forms the point of attachment between the rod P and the lever O, the
connection being effected by means of a short intermediate rod for the sake of insuring parallelism of
motion. A pair of small spur-wheels r, (through the first of which the rod P works by means of a
sunk feather,) serve to transmit the angular motion of the rod P to a similar screwed-rod U, situated
parallel to and at a short distance from the former; the nut of the screw U forms the fulcrum or centre
of motion of the lever O, and the pitch of the threads of both screws being equal, though formed in con-
trary directions to each other, it is obvious that, on turning the handle, the lever o and all its appen-
dages will be simultaneously raised or depressed, and consequently the lift of the hammer regulated to
any required extent, and its amount altered with the utmost ease and precision. The pin which forms
the centre of motion of the lever o is protected and secured from lateral strains by the cast-iron guides
V and W, seen most distinctly in the sectional plan, Fig. 2245.
A most essential part of the self-acting geer remains yet to be noticed. It is obvious that, were no
provision made for the retention of the steam-valve in the position into which it is thrown by the up-
ward motion of the hammer-block, the latter would not be permitted to have its due effect in the
accomplishment of its work; for, as soon as it descended 80 far as to relieve the end of the lever o from
contact with the tappet N, the valve would resume the position into which it is constantly solicited by
the action of the steam-spring at M, and the descent of the blow would be impeded by the return of the
steam into the cylinder, before the hammer had completed its fall. To obviate this inconvenience, a
simple but most effectual contrivance has been applied. Towards the lower extremity of the valve-
screw P a shoulder is formed, against which a short lever w, called the trigger, is constantly pressed by
the spring x, 80 that when the rod P is depressed by the action of the lever O, it is arrested by the
trigger and retained in that position until the blow has been struck. This delicate and most important
part of the mechanism is very carefully constructed, the point of the trigger, and the shoulder against
which it acts, being formed of steel, and hardened to resist wear.
To release the valve-screw from the trigger, and so permit the return of the valve into the position
requisite for effecting a fresh stroke, the following mechanism has been adopted on the front of the
hammer-block, Figs. 2244 and 2248, a lever X, called the latch-lever, is fitted to work freely on a pin
passing through the body of the hammer-block. That portion of the latch-lever which is most remote
from the valve-geer is considerably heavier than the opposite end, and is constantly pressed upwards
by means of a spring. The lighter end is brought into contact with a long bar 88, called the parallel
bar, the extremities of which are suspended upon two small bell-cranks tt, whose other arms are con-
nected by means of a slender rod u, Fig 2247, forming a species of parallel motion, for the purpose of
adapting this geer to come into efficient operation, at whatever point in the range of the hammer its
blow may be arrested. A small connecting-rod v, between the lower bell-crank and a short lever on
the axis of the trigger w, completes this part of the mechanism.
The action of this geer is of a very peculiar nature, and is admirably adapted to fulfil the object in-
tended. At the instant the hammer gives a blow to the work upon the anvil, the effect of the concus-
sion is to cause the momentum of the heavy end of the lever X to overcome the upward pressure of the
spring, and thereby to protrude its opposite end against the edge of the parallel bar 8, which motion,
though but slight in amount, is yet adequate, through the arrangements above described, to throw back
the trigger from contact with the valve-screw, and leave the latter free to obey the impulse of the steam-
spring in the readjustment of the valve into its original position.
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These various movements, which have taken 80 long to describe, are all performed in less than half
a second, and consequently the action of the hammer is proportionally rapid.
The construction of the self-acting geer is so arranged as to admit of advantage being taken, when
circumstances render it desirable, of the very action to obviate which the trigger w is introduced. When
it is desired to strike a gentle blow, such as is frequently required during particular stages in the prog-
ress of a piece of work, it is not requisite, for this purpose, to change the position of the valve-lever O.
All that has to be done is to hold back the point of the trigger 20, by its handle y; this permits the
valve to reopen and let the steam in under the piston L, at the instant the tappet N has fallen away
from contact with the lever O. The effect of this is, that a quantity of steam is admitted into the cylin-
der under the piston, which serves as a cushion, by which the violent fall of the hammer is arrested,
and its momentum modified to any extent, or at the pleasure of the person in charge of the handles.
The handle z, is for the purpose of placing the steam-valve also under his control, and, for his further
convenience in the management of the hammer, a platform Y and hand-rail Z are erected against the
framing of the machine.
A modification of the frame of this machine has been made at the Washington Navy Yard, one sup-
port only being used, by which means access is had to the anvil on all sides except that occupied by
the support.
HAMMER, Tilt or Trip. See TILTING.
HARVESTER. An agricultural machine for reaping and gathering in grain, much used in the
western country. There are many forms of them, known in this part of the country as REAPERS,
which see.
HAT-MAKING embraces two distinct kinds of manufacture, felted and covered hats; the covering
of the latter being sometimes silk, and at other times cotton.
Felted hats comprehend two classes, differing chiefly in the materials used in making, the process
being nearly identical. The lower class is marked by inferior ingredients, unmixed with beaver, and
embraces wool, plated, and short-nap hats.
Wool hats are made entirely of coarse native wool and hair stiffened with glue. Plates have a nap
or pile rather finer than their body, and are sometimes water-proof stiffened. Short naps are distin-
guished from plates by additional kinds of wool, viz. hare's back, seal, neuter, musquash, (Muscovy cat,)
and are all water-proof stiffened.
The second class may be said to comprehend two orders, called stuff and beaver hate. The first in-
cludes mottled and stuff bodies. The latter term is not used generally, as all stuffs are understood to
be of this sort when mottled is not expressed. Mottled bodies are made chiefly of fine wool, and inferior
rabbit down or coney wool. Stuff bodies consist of the best hare, Saxony, and red wools, mixed with
Cashmere hair and silk. Stuff hats are napped, that is, covered with pile of mixed seal, neuter, hare-
back, inferior beaver, and musquash. Beaver hats are, or ought to be, napped with beaver only the
lower priced qualities with brown wooms taken from the back; the more valuable kinds with cheek and
white wooms, being the finest parts of the fur found on the belly and cheeks of the beaver.
The apparatus and terms used in making felted hats, which it is necessary to describe briefly, are the
bow, basket, hurdle, battery, and planks.
The bow is about six feet long, usually made of ash, thick enough not to be elastic. The handle is
called the stang. The bmo-string is a strong catgut cord tensely fastened.
The hurdle is a fixed bench, with three enclosing sides, to prevent the stuff being flittered off in
bowing.
The basket is of light wicker-work, about twenty by twenty-two inches in size.
The battery consists of the kettle and the planks. which are inclined planes, usually eight in number,
one only being appropriated to each workman. The half of each plank next the kettle is lead, the
upper half is mahogany.
The first process in hat-making is bowing the stuff or furs, which are weighed out to a proportionate scale,
and laid on the hurdle, immediately under the bow, which is suspended by a pulley. The bow is held
firmly with the left hand, rather towards the breech-end, not edgewise, but on its side, with the string in
contact with the stuff, the clotted and adherent portions of which are separated into single fibres, and
attain a loose, flocky, mixed condition by the continued vibration of the bow-string, caused by a very rapid
succession of touches with the bow-stick. It is then divided as nearly as possible, and one-half laid aside,
whilst the other is again bowed. In this second operation, partly by the bowing, but chiefly by the gather-
ing, or patting use of the basket, the stuff is loosely matted into a conical figure, about fifty by thirty-six
inches, called a bat. In this formation care is taken to work about two-thirds of the wools down to-
wards what is intended for the brim, which being effected, greater density is induced by gentle pressure
with the basket. It is then covered with a wettish linen cloth, upon which is laid the hardening skin,
a piece of dry half-tanned horse-hide. On this the workman presses or bakes for seven or eight
minutes, until the stuff shall have adhered closely to the damp cloth, in which it is then doubled up,
freely pressed with the hand, and laid aside. By this process, called basoning, (from a metal plate er
bason, used for like purposes in making wool hats,) the bat has become compactly felted and thinned
towards the sides and point. The other half of the flocked stuff is next subjected to precisely the same
proceedings, after which, a cone-shaped slip of stiff paper is laid on its surface, and the sides of the bat
folded over its edges to its form and size. It is then laid paper-side downward upon the first bat,
which is now replaced on the hurdle, and its edges transversely doubled over the introverted side-lays
of the second bat, thus giving equal thickness to the whole body. In this condition it is reintroduced
between folds of damp linen cloth, and again hardened, 80 as to unite both halves, the knitting together
of which is quickly effected. The paper is now withdrawn, and the body being folded into three plies,
is removed to the plank or battery-room.
In the battery the liquor is scalding heat, composed of pure soft water, with about half a gill of
oil of vitriol as an astringent. Herein the body is imbrued, and withdrawn to the plank to partly
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HAT-MAKING.
cool and drain, when it is unfolded, rolled gently with a pin tapering towards the ends like a liquor
horse, turned, and worked with in every direction, to toughen, shrink, and at the same time prevent
adhesion of its sides. Stopping or thickening the thin spots which now appear on looking through the
body, is carefully performed, by additional stuff daubed on by successive supplies of the hot liquor
from a brush frequently dipped into the kettle, until the body be shrunk sufficiently, (about one-half,)
and thoroughly equalized. When quite dried, stiffening is performed with a brush dipped into a
glutinous pulpy composition, and rubbed into the body; the surface intended for the inside having much
more imposed than the outer, while the brim is made to absorb many times the quantity applied to
any other part. This viscous matter contains proofing, or those ingredients which render the hat water-
proof.
On being again dried, the body is ready to be covered, and is once more taken to the battery. The
first cover of beaver or napping, which has been previously bowed, is equally strewed on the body, and
patted upon with the brush charged with the hot liquor, until incorporated; the cut ends only being
the points which naturally intrude. Here the body is put into a coarse hair-cloth dipped and rolled in
the hot liquor, until the beaver is quite worked in. This is called rolling off, or ruffing. A stripe for
the brim round the edge of the inside, is treated in like manner, and is thus prepared for the second
cover, which is applied and inworked in like manner: the rolling, &c., being continued until the whole
has become incorporated, and a clean, regular, close, and well-felted hood is the result. The dry hood,
after having the nap beat up and freed, is clipped to the length which may be thought best, by means
of common shears. A clipping machine, invented nearly four years ago in Scotland, is now very
generally preferred, and doubtless will soon everywhere supersede the ordinary process; much greater
regularity, speed, and certainty being secured by it. When the nap is thus disposed of, the hood is
soaked in the battery kettle, and then drawn down on a block to the size and shape wanted, firmly tied
at the bottom with a cord, around which the brim is left in a frilled condition.
Dyeing is the next step. A suit, or six dozen, are put into the dye-kettle at a time, all on the crown-
blocks already mentioned, and allowed to remain three-quarters of an hour in the liquor, which is kept
as near as possible one degree below the boiling point. These being taken out and set in the yard to
cool, another suit is introduced for a like period, and the various suits are 60 treated at least twelve
times in successive order. Each of the first four introgressions of every suit is accompanied by about
seven pounds of copperas, and two pounds of verdigris. The body is then washed and brushed out in
changes of hot water, until no coloring can be recognized in it. When thus thoroughly cleansed, it is
steamed on a block shaped as the hat is wished to be when complete; and in the finishing shop by
neavy (21-pound) heated irons and moisture, the frilled brim is shrunk until rendered quite level, the
nap gently raised all over with a fine wire card, and brushed and ironed smooth in the uniform direc-
tions. The tip, a thin lath-sheet, is then fitted and stuck to the inside of the crown, and robbined or
secured all round the edges by stripes of prepared paper. When thus got down, it is sent to the picker,
who, with tweezers, extracts the kemps, or "gray hairs," which are a few of those thick fibres peculiar
to the fur of amphibious animals, that have escaped the search of the machine used in blowing the
beaver, 80 as to separate them from its fine parts. This being carefully accomplished, it is transferred
to the finisher, who, with a plush cushion, a brush, and hot iron, imparts to it that bright sleeky
lustre. The shaper then rounds the brim with a knife and notched segment to the breadth wanted;
and shapes it in varied styles by means of a hot iron and damp, with about a foot length of rope,
over which the curl is laid. The trimming is next done, when the tipper-off corrects the twists,
smooths the ruffled nap caused by trimming, and papers it up with tissue and cartridge, which com-
pletes it for the retailer.
Silk hats are made upon bodies of wool, stuff, willow, straw, and Leghorn plait, and cambric and
woollen cloth, although chiefly on felted wool bodies, which are dipped in glue size, wrung out, blocked,
and dried. The tip is then fitted and robbined, when a flour-box, charged with powdered shell-lac and
rosin in like quantities, is used to strew equally its grainy mixture on the external surface of the shell,
so called from being the frame-work. This is burned in by hot irons, first on the top, which passes
through to the lath-tip within; then on the upper brim, the sides, and, finally, the under brim. When
this is hardened it is coated with thick ordinary flour-paste, which is dried, and the shell again blocked
and smoothed; then once more glue-sized outside, dried, and varnished, which prepares it for covering.
The shag for the sides is cut across the web, in a ratio of obliquity increased by inferiority. This cross
part is sown to a circular piece for the crown, whilst the brims are singly patched together. These
preparations being completed, the top-side or upper brim is first stuck, then the crown, next the sides,
and, finally, the under brim. Sticking is effected simply by the heat of the iron passing through the
covering and melting the varnished surface. In the finish of this manufacture, the most particular part
is the side-seam, which is disposed of thus The selvidge end is cut perpendicularly from top to brim,
by a sharpened pallet-knife, the nap having been previously brushed clear off its edge. The other
selvidge end is then stuck and cut with the utmost nicety, in close parallel with the other. It is then
finished very much in the same manner as a beaver hat.
The above-mentioned method of making hat-bodies is now mostly superseded in this part of the
country by the adoption of machinery, the manual labor being confined to the getting up the hat, and is
a distinct business; the hatter for the most part purchasing his hat-bodies far cheaper than he can
make them.
The machinery is very simple. The fur or hair of which the felt is to be made, after being cleaned
and lightly beat up, by passing through a kind of winnowing machine, is delivered to a boy, who
spreads the fur very lightly and in small quantities on an endless web before him, which, passing between
rollers, carries the fur into the body of the machine, where it encounters a cylindrical brush in rapid
motion, which separates the hair or fur completely, throwing it towards a contracted opening in the
sides of the cylinder-case. This opening, about an inch wide at top and nearly three inches at
bottom, is in height equal to the cone of the hat-body. Immediately in front, and close to this opening,
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is placed a perforated copper cone, the perforations 80 small, and in such number, as almost to render
the surface of the cone, from base to apex, a wire-gauze surface. This cone is open at the bottom and
placed on an opening equal to its base, which opening is in communication with a fan or blast, so
arranged as to exhaust the interior, or "suck," 80 to speak, the air through the meshes of the copper
cone. The hair or fur in its divided state, thrown towards this opening in the cylinder-case, is brought
under the influence of the powerful draught towards and through the cone; the latter at the same time
slowly revolving on its axis, exposes all its sides to the opening, and the hair is driven against it with
such force as to adhere for the time, and receive and retain on all sides, as it revolves, the fine particles
of hair as they are drawn from the cone. In the space of half a minute a dry hat-body is formed
on the copper cone; this is immediately enveloped by a wetted felt, and the whole immediately
removed, and its place supplied by a fresh copper while the first is being stripped of its now wet felt.
The whole operation is performed with wonderful dispatch, the hat-body resulting from it being ex-
ceedingly light and uniform in texture, and requires but little labor before it is in condition to be trans-
ferred to the hands of the batter for working up. In this manner any form of felt may be made. The
opening in the cylinder-case being of flexible metal, admits of adjustment to the wants of the particular
form of the felt to be constructed. The application of this principle is universal in the manufacture of felt.
HAY AND CORN OUTTER. J. ROMAN'S rotary and vibrating self-feeding cutter, patented June
20th, 1848, is well adapted to farmers in cutting hay, straw, and corn fodder, and grinding the latter to
any fineness required, without any more power comparatively added. It has decided advantages:
First, it presents more edge of knife, and nearer to the centre, therefore having all advantages of the
power both in cutting and grinding. In ordinary machines it presents from three to five feet of edge;
this depends on the diameter of the knives used, as the last part of the cut is effected with as much
ease as the first. This is owing to the vibration of the box, and the rotary motion of the knife at the
same time, as the substance, whilst being cut, is not a greater distance than five inches from the centre
shaft.
2249.
1
JUNE 20 1848.
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J. ROMAN'S PATENT.
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This machine may be adapted to the use of bookbinders, for the purpose of cutting paper or the
edges of books, and for harness-makers or shoemakers. It is also well adapted to the cutting of dried or
fresh meat and bread, and can, with advantage, be used in almost every branch of the useful arts in
which fibrous or texile substances have to be cut to any great extent,
9950
as there can be a series of knives on the same shaft, 80 as to expedite
the business required; and, also, the knife or knives may be serrated or
B
smooth, best adapted to the substances required to be cut.
The operator takes hold of handle H and turns it, which revolves the
crank F and G and the wheel D; the wheel D geers into pinion I, which
A
revolves the knife B and the balance-wheel J, which are on the shaft K;
the crank F, in the mean time, through the connecting-rod L, vibrates the
holder or box C by the arm M, alternately before and to one side of the
knife at the same time; at the same time the crank G, through the agency
c
of the connecting-rod N, depresses the lever o and the ratchet-dog Q
which hooks upon and turns the wheel R, and with it the feed-rollers S
advance the fodder or substances required to be cut every time the feed-
box or holder, during its vibrations, moves to one side of the knife.
HEART-WHEEL A contrivance for converting a uniform circular
motion into a uniform rectilinear motion. It is much employed in the
machinery of the cotton and flax manufacture, and is formed after the
following manner: Draw a line A B equal in length to the required ex-
120
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HEAT.
tent of the alternating rectilinear motion, and divide this line into any number of equal parts, the more the
better. From the centre, C, round which the heart-wheel is to move, with any distance (which need not
be great) describe the semicircle A bc, and divide it into the same number of equal parts as the line
AB. From the centre draw radii passing through each of these points, and extend them a considerable
way beyond the circumference. Next from the centre C take the distance to the first division on the
line A B, and lay off that distance on the first radius, passing through the division on the semicircle,
then take the second, third, fourth, &c., divisions from the centre C in succession on the line A B, and lay
them off successively on the second, third, fourth, &c., radii, then will a line drawn through all these
points on the radii be the face of one half of the wheel. The other half is formed after the same
manner. The curve of the face of the wheel is in this case the spiral of Archimedes, but the alternating
rectilinear motion may be made to follow any given law besides that of uniformity, by changing the
nature of the curvature of the face of the wheel, which may be easily done by making the divisions on
the line A B increase or diminish from the centre or the ends, and constructing the figure in other
respects as before.
HEAT. Heat, in the ordinary application of the word, signifies, or rather implies the sensation ex-
perienced upon touching a body hotter, or of a higher temperature, than the part or parts which we
bring into contact with it: in another sense, it is used to express the cause of that sensation. To avoid
any ambiguity that may arise from this double use of the same expression, it is usual and proper to
employ the word caloric to signify the principle or cause of the sensation of heat. On touching a hot
body, caloric passes from it, and excites the feeling of warmth: when we touch a body having a lower
temperature than our hand, caloric passes from the hand to it, and thus arises the sensation of cold.
Caloric is usually treated of as if it were a material substance; but, like light and electricity, its true
nature has yet to be determined.
Caloric passes through different bodies with different degrees of velocity. This has led to the division
of bodies into conductors and non-conductors of caloric: the former includes such bodies as metals which
allow caloric to pass freely through their substance, and the latter comprises those that do not give an
easy passage to it, such as stones, glass, wood, charcoal, &c.
Table of the relative Conducting Power of different Bodies.
Gold
1000
Platinum
981
Silver
973
Copper
898
Iron
374
Zinc
363
Tin
304
Lead
180
Marble
24
Porcelain
122
Fire-brick
11
Fire-clay
11.4
With Water as the Standard
Water
10
Elm
32
Pine
39
Ash
31
Lime
39
Apple
28
Oak
33
Ebony
22
Relative Conducting Power of different Substances compared with each other,
Hares' fur
1.315
Cotton
1046
Eider-down
1-305
Lint
1032
Beavers' fur
1-296
Charcoal
937
Raw silk
1.284
Ashes (wood)
927
Wool
1.118
Sewing-silk
917
Lamp-black
1.117
Air
576
Relative Conducting Power of Fluids.
Mercury
1·000
Proof spirit
312
Water
357
Alcohol (pure)
232
Radiation of caloric.-When heated bodies are exposed to the air, they lose portions of their heat,
by projection in right lines into space, from all parts of their surface.
Bodies which radiate heat best, absorb it best.
Radiation is affected by the nature of the surface of the body; thus, black and rough surfaces radiate
and absorb more heat than light and polished surfaces.
Table of the Radiating Power of different Bodies.
Water
100
Blackened tin
100
Lamp-black
100
Clean
"
12
Writing-paper
100
Scraped
"
16
Glass
90
Ice
85
India-ink
88
Mercury
20
Bright lead
19
Polished iron
15
Silver
12
Copper
12
Reflection of caloric differs from radiation, as the caloric is in this case reflected from the surface
without entering the substance of the body: hence the body which radiates, and consequently absorbs
most caloric, reflects the least, and vice versd.
Latent caloric is that which is insensible to the touch, or incapable of being detected by the thermom-
eter. The quantity of heat necessary to enable ice to assume the fluid state is equal to that which
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would raise the temperature of the same weight of water 140°; and an equal quantity of heat is set
free from water when it assumes the solid form.
If 5f lbs. of water, at the temperature of 32°, be placed in a vessel communicating with another one,
(in which water is kept constantly boiling at the temperature of 212°,) until the former reaches this
temperature of the latter quantity, then let it be weighed, and it will be found to weigh 6} lbs., showing
that 1 lb. of water has been received in the form of steam through the communication, and reconverted
into water by the lower temperature in the vessel.
fow this pound of water, received in the form of steam, had, when in that form, a temperature of
212'. It is now converted into the liquid form, and still retains the same temperature of 212°, but it
has caused 57 lbs. of water to rise from the temperature of 32° to 212°, and this without losing any
temperature of itself. It follows, then, that in returning to the liquid state, it has parted with 5f times
the number of degrees of temperature between 32° and 212°, which are equal 180°, and 180° X 51 =
990°. Now this heat was combined with the steam; but as it was then not sensible to a thermometer,
it was called Latent.
It is manifest, then, that a pound of water, in passing from a liquid at 212° to steam at 212°, receives
as much beat as would be sufficient to raise it through 990 thermometric degrees, if that heat, instead
of becoming latent, had been sensible.
The sum of the sensible and latent heat of steam is always the same at any one temperature; thus,
990° + 212° = 1202°.
If to a pound of newly fallen snow were added a pound of water at 172°, the snow would be melted,
and 32° will be the resulting temperature, 138° of heat becoming latent in the melted snow.
Latent Heat of various Substances.
Fluids.
Vapors.
Ice
140°
Steam
990°
Sulphur
144
Vinegar
875
Lead
162
Ammonia
860
Beeswax
175
Alcohol
442
Zinc
493
Ether
302
Sensible caloric is free and uncombined, passing from one substance to another, affecting the senses in
its passage, determining the height of the thermometer, and giving rise to all the results which are
attributed to this active principle. See STEAM.
It is frequently desirable to convert the degrees of heat, as indicated by one thermometer, into its
equivalent as denoted by another. The following rules will serve this purpose for the thermometers in
general use:-
To reduce the degrees of a Fahrenheit thermometer to those of Reaumur and of the centigrade the
zero of the Reaumur scale being at the freezing point, and 80° at the boiling point, whilst the zero of
the centigrade is at the freezing point, and 100° at the boiling. See THERMOMETER.
Fahrenheit to Reaumur.-Rule.-Multiply the number of degrees above or below the freezing point
by 4, and divide by 9.
Thus, 212° - 32 = 180 X 4 = 720 ÷ 9 = 80, Ans.
+ 24° 32 = 8 X 4 = 32 ÷ 9 = 3.5, Ans.
or 3.5 below zero.
Fahrenheit to centigrade.-Rule.-Multiply the number of degrees above or below the freezing point
by 5, and divide by 9.
Thus, 212° 32 = 180 X 5 = 900 ÷ 9 = 100, Ans.
Or multiply the degrees of Fahrenheit by 444 for reducing them to Reaumur, and by 555 for reducing
them to centigrade.
Medium heat of the globe is placed at 50°; at the torrid zone, 75°; at moderate climates, 50°; near
the polar regions, 36°.
The extremes of natural heat are from 70° to 120°; of artificial heat, from 91° to 36,000°.
Evaporation produces cold, because caloric must be absorbed in the formation of vapor, a large
quantity of it passing from a sensible to a latent state, the capacity for heat of the vapor formed being
greater than that of the fluid from which it proceeds.
Evaporation proceeds only from the surface of the fluids, and therefore, other things equal, must depend
upon the extent of surface exposed.
When a liquid is covered by a stratum of dry air, evaporation is rapid, even when the temperature
is low.
Table of Effects upon Bodies by Heat.
Fahrenheit.
Fahrenheit.
Cast-iron, thoroughly smelted
2754°
Lead, melts
594°
Fine gold, melts
1983
Bismuth, melts
476
Fine silver, melts
1850
Tin, melts
421
Copper, melts
2160
Tin and bismuth, equal parts, melt
283
Brass, melts
1900
Tin 8 parts, bismuth 5, and lead 2, melt
212
Red heat, visible by day
1077
Alcohol, boils
174
Iron, red-hot in twilight
884
Ether, boils
98
Common fire
790
Human blood (heat of)
98
Iron, bright-red in the dark
752
Strong wines, freeze
20
Zinc, melts
740
Brandy, freezes
7
Quicksilver,"boils
630
Mercury, melts
-89
Linseed oil boils
600
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HEDDLES.
Wedgewood's zero is 1077° of Fahrenheit, and each of his degrees is equal to 130° of Fahrenheit.
Expansion of Solids.
At 218°, the length of the bar at 32° considered as I-0000000.
Glass
0008545
Gold
0014950
Platina
0009542
Copper
0017450
Cast-iron
0011112
Brass
0019062
Steel
0011899
Silver
0020100
Marble
*0011041
Fire orick
*0004928
Forged iron
0012575
Lea 1
0028436
Granite
0007894
Zin
0029420
To find the expansion in surface or in volume, it must be remembered that each dimension of a solid
experiences a similar proportional expansion.
Table of the Expansion of Air by Heat.-By Mr. DALTON.
Fahrenheit.
Fahrenheit.
Fahrenheit.
32°
1000
50°
1043
80°
1110
83
1002
55
1055
85
1121
34
1004
60
1066
90
1132
35
1107
65
1077
100
1152
40
1021
70
1089
200
1854
45
1032
75
1099
212
1376
Melting Point of Alloys.
Lead 2 parts, tin 8 parts, bismuth 5 parts, melts at
212°
"
1
"
«
4
"
"
5
"
melts at
246
a
1
"
"
1
"
melts at
286
"
2
«
"
1
"
melts at
336
a
2
"
"
8
"
melts at
334
"
8
"
as
1
"
melts at
892
"
2
«
"
1
"
common solder,
melts at
475
"
1
"
"
2
"
soft solder,
melts at
360
Boiling points.The boiling point of water, from 27 to 31 inches of the mercurial column, varies
165° for every inch, being at 80 inches 212° and on this variation is founded the apparatus for deter-
mining altitudes.
Comparative Heat from various Fuels.
1 lb. of tolerably good coal will raise the temperature of 60 lbs. of water from 32° to 212°.
1 lb. of kiln or perfectly dried wood will effect the same on 35 lbs.
1 lb. of wood simply dried in the air
"
"
26 lbs.
1 lb. charcoal
"
"
79 lbs.
Turf of good quality yields as much heat for equal weights as wood, and the heat it gives out by
radiation whilst burning has been considered even greater than that of wood.
For the various methods of applying heat to the warming of buildings, see article WARMING.
HEDDLES, Machine for making Weavers'. This machine is the invention of Mr. KASSIMIR VOGEL,
of Lowell, Massachusetts.
The object of the machine is to make weavers' heddles from the thread, casting the loop by braiding
instead of knotting, and performing triple the amount of work, and better than can be done by hand.
A patent is also secured for the peculiar eye of the heddle, so that both machine and its results are
protected.
Description.-Fig. 2251 is a perspective view, and shows gangs of different heddles winding on the
beams. A A is the iron framing. B are the driving and slack pulleys. C is the lever to geer and un-
geer. EE are the bobbins, with the thread to make the heddles. There is a small shaft under the bed
of E, which, by small cog-wheels on the same, operate and revolve the bobbins by geering into F. II
are the heddles after the eye is formed, winding up on the beams LL The gang of wheels at the left
are for the purpose of connecting the shafts of the beams to be driven by the main shaft below. The
number of eyes to the foot in the heddles can be increased or diminished by the geering of these small
wheels. K is a small bearing for the shaft of L, and J is the shaft with a screw cut on part of it. This
is for winding the heddle gradually along the beam, and as K is a grooved and wormed faced pulley
driven slowly by the small gang of wheels at the right, the shaft J is wormed slowly through its bear-
ings, carrying the beam to let the heddles wind one after another on the same. The heddles are formed
of a double cord, which is twisted by the bobbins revolving. and the eyes or loops are formed by the
bobbins being interlocked, braiding the two strands at the two points which form the eye of the heddles.
The section views will explain the operations better in detail.
As the same letters indicate like parts on all the following engravings, we shall describe them col-
lectively. Fig. 2252 is a side elevation. Fig. 2253 is a top view of the revolving tables and spindles.
Fig. 2254 is an end elevation. Fig. 2255 is a view of the under side of the machine, showing the geer-
ing by which the tables that carry the spindles are made to revolve.
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HEDDLES.
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A is the heddle-beam. BBBB are revolving spool-frames or tables. C represent the spool-spin-
dles. a are slots in the spool-tables. Each table has six slots or spindle recesses, but only three are
occupied at once with the spindles. As the tables revolve, three slots are occupied with spindles and
three are empty alternately, and an occupied slot in one is brought opposite to an empty recess in its
2251.
c
L
I
I
I
I
I
J
L
A
K
B
E
H.
F
H
A
A
fellow-table, as seen in Fig. 2253. The tables BB constitute one pair, and the tables B 2, B 3, another,
forming two distinct harness, one on each side on two beams, but driven by the same geering. The
yarn is put on the spindles C, and passes through a hole in the top of the fiyers D, or over a depression,
Fig. 2252, to hold it in its place, and then passes under c, a recurved wire, that has a perforated weight
M.
2252.
J
Q
II
P
n
0
K
D
c
c
c
0
N
B
B
E
E
J
I
H
F
F
dd at each end. The flyers pass through these holes, and the legs serve as guides to the weights.
This is to take up the slack of the yarn. The spindles have each a groove in their lower parts, adapted
to slide into the recesses of the tables when the recesses coincide. The platform EE has circular
cavities for the lower ends of the spindles. FF, Fig. 2252, are fast and loose pulleys to drive the
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HEDDLES.
shaft G. A bevel-wheel H, on G, gives motion to the revolving spool-tables by toothed wheels, as seen
at Fig. 2255. The bevel-wheel I, Fig. 2252, gives motion to the heddle-beams by geering into J, on
the shaft K. This shaft carries a worm-wheel, which geers into M to drive A. N is an eccentric on K
2253.
A
of
P
c
a
B
B
N
a
E
E
L
c
B
B
c
a
P
A
to vibrate g, a shipper, which shifts the spindles from one table to another; the opposite ends of g
operate on two pairs of tables. A connecting-rod with N vibrates the shippers. N is connected with K,
and turns with it by clutch-pins, and when these are not engaged the shafts turn without N. ii, Fig.
2254, is a pin that passes through N, projecting out above and below, nearly in contact with K. There
2254.
L
M
I
M
P
0
K
i
0
M
m.
"
F
are two clutch-pins on K, either of which may be brought in contact with i, as the eccentric-wheel is
made to slide up and down on the shaft. 0, Figs. 2252 and 2254, is a forked lever with its fulcrum at e
Its fork ends m m embrace N, the eccentric, and raise and lower it at proper times. nn is a spiral
spring attached to the forked lever, serving to draw it inwards to depress the eccentric and make it
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HELIOTROPE.
959
clutch with the lever clutch-pin. On the wheel M are cams or lifting pieces pp, which, when they
come in contact with the end of 0, force it out and raise N, the eccentric, so as to engage with the
upper clutch-pin at the required time, as will be understood by Fig. 2254. The axis of A is P, a screw,
Fig. 2252, tapped into the frame of the machine and moves A endwise as it revolves, to wind the
heddles, as they are made spirally on the beams. q is the smooth axis of A, on which the beam slides,
moved by the screw on the guide-rods rr. QQ are rods that may be inserted in grooves in A. The
semi-diameter of A must be of the length of the heddles. After the number of heddles for a harness
have been made, grooved pieces may be slipped over Q and glued upon them to embrace the twisted
strands, or any other mode may be adopted. The shipper connecting-rod h, (which looks like an n,)
Figs. 2252 and 2253, has a hinge-joint t, to allow it to be lifted from the shipper g. The small bevel-
wheel J, on the shaft K, is one-third of the diameter of the driving-wheels, when there are three spindles
on the table, and therefore makes the changes of the spindles in the recesses in one revolution of the
revolving spool-tables. If there were four spindles in the table, the wheel J would be one-fourth the
diameter of the driving-wheel, &c.
9955.
E
E
a
I
H
To explain its operation, Fig. 2251 exhibits a different arrangement of mechanical parts from the sec-
tion views, but they are just the mechanical equivalents to accomplish the same thing. Heddle or
harness making is the formation of eyes by two cords being knotted together. These eyes must be
formed at regular distances on the harness. This machine forms two cords by BB, revolving and twist-
ing the yarn on the three spindles, one by each table revolving, the cord winding at the same time as it
is twisted on the beam A. Now to form four eyes on the heddles every revolution of the beam,
look at Fig. 2253. If the strands that make the two cords were interlocked at certain periods, eight
times during the revolution of A, that four eyes would be formed by the strands of the two cords being
thus at certain points braided into one another. This is the way this machine does its work, and this
can be done by the forked lever in Fig. 2254 shifting the shipper, or by cams on the inside of the upper
geer-wheel of Fig. 2251. To make the spindles in c interlock to braid the eyes. The cams or clutch
operate the shipper g, so that instead of vibrating from side to side, as now seen in Fig. 2253, touching
the spindles outside, it is (the shipper) stopped by the resting of the eccentric one-sixth of the revolu-
tion of the tables, and then it will be easily perceived that the shipper will take into the inside of the
spindle e and throw it into the empty recess a of the other table, which coincides, thus interlocking the
threads and braiding the two cords together into one, forming an eye of the heddle by braiding instead
of knotting. It will be observed, too, that the clutch can be changed by cams, to operate the shipper,
to make as large or as many eyes in a foot as may be desired: but the changing or passing of the
spindles from one table to another must be performed by the shipper twice for one eye, according to
the length of the eye, and they are not shifted again until A has revolved the distance wanted to form
the base of a new eye for the harness.
HELIOTROPE Reflecting Lantern, used by Major J. D. GRAHAM as meridian marks for great distances,
in 1841, while tracing the due north line from the monument at the source of the river St. Croix.
The lantern was constructed by Messrs. Henry N. Hooper & Co. of Boston, under Maj. G's directions.
It was similar in form to the Parabolic Reflector Lantern, sometimes used in light-houses, but much
smaller, 80 as to be portable.
The burner was of the argand character, with a cylindrical wick, whose transverse section was half
an inch in diameter, supplied with oil in the ordinary manner. This was placed in the focus of a para-
bolic reflector, or paraboloid, of sheet-copper, lined inside with silver about 1-20th of an inch in thick-
ness, polished very smooth and bright. The dimensions were as follows:
Inches.
Diameter of the base of frustrum of reflector
16.
Distance of vertex from base
8-75
Distance of focus from vertex
2.25
Diameter of cylindrical burner
50
Diameter of a larger burner which was never used, but which, by an adapting piece,
could be easily substituted
1.25
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960
HELIOTROPE.
The instrument answered the purpose for which it was intended admirably well, and was of great
use in tracing the due north line. While it occupied the station at Park's Hill, 15 feet above the sur-
face of the ground, or 828 feet above the sea, in the latter part of September and early part of October,
1841, the light from it was distinctly seen with the naked eye at night, when the weather was clear,
from Blue Hill, whose summit, where crossed by the meridian line, is 1071 feet above the sea, the
intervening country averaging about 500 feet above the sea, and the stations being 36 miles apart.
The light appeared to the naked eye, at that distance, as bright, and of about the same magnitude,
as the planet Venus. Viewed through the transit telescope, of 48 inches focal length, it presented a
luminous disk, of about 30 seconds of an are in diameter.
The wick employed by Major G. was considerably smaller than that usually made, even for parlor
lamps; and to this cause is attributed, in a great measure, the perfection with which the parallel rays
were transmitted from the reflecting parabolic surface, 80 as to make them visible at 80 great a distance.
Though a greater quantity of light is generated by a larger wick, the portion of rays reflected in a
direction parallel to the axis, and which alone come to the eye, is the smaller as the flame transcends
the focal limit. The size of wick most advantageous for use may easily be determined by experiment.
The smaller is its transverse section. provided it is only large enough to escape being choked up by
the charred particles, even one-third, or perhaps one-fourth of an inch, the further the light would be
visible.
Lanterns of this description might be used with great advantage as station-marks in extensive trigo-
nometrical surveys, requiring primary triangles of great length of sides. A revolving motion might be
given to the lanterns, 80 as to make the light transmitted from them visible from many different stations
within short intervals of time. Their simplicity, and the ease with which they are managed, would
perhaps give them, for such purposes, a great advantage over the Drummond or Bude lights, even
though they be not so brilliant as the latter.
The heliotrope, which is employed in the day-time, was made by order of Mr. Hassler, at the instru-
ment shop of the coast-survey office. It was a rectangular parallelogram of good German plate-glass,
1 4-5ths by 1 1-5th inch in size, giving an area of reflecting surface of 2100 square inches. This also
was seen at the distance of 36 miles.
END OF VOL I.
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UNIVERSITY OF MICHIGAN