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October 2nd,1928.
Dr. Herman Schlundt,
University of Missouri,
Department of Chemistry,
Columbia, No.
Dear Dr. Schlundt:
The introduction as well as part one of the experimental
part of our paper has been received.
I have read your subject matter carefully several times
and don't know as I can offer mach in the way of constructive criticism.
There are one or two points, however, which I wish to call to your attention
for further consideration: On page one of the introduction, toward the end
of the first paragraph you state that an experienced operator can determine
quantitatively one millionth of a microgram of radium.
This amount offhand
seems almost beyond the range of accurate work, even with delicate instruments -
for instance, our experience indicates that it requires approximately five (5)
millimicrograns of radium element to cause the leaf to fall one division per
second. The quantity indicated by you would be approxinately 1/50 of this
amount, which would mean a drift of approximately one dévision per minute for
the
large chamber Lind electroscope - this it seems to me ie approaching the
limit for accurate W ork with this type of instrument.
On page 1 of part 1. experimental, at the bottom of page:
What would you think of introducing in parenthesis the amont of Tadium which
we feel and experienced nan, working under carefully controlled conditions,
would give a positive test. As you know Dr. Flinn and I both feel that we
can positively detect quantities of less than 5 micrograms, and I can see
no reason to expressing in a géneral way the amounts which up to the present
time
we
fel
we can detect. I don't know as I would want to go down to a
quantity of one microgram, but I do feel that wâth carefully controlled con-
ditions and repeated tests that a quantity of two micrograms could be detected.
I merely suggest this for consideration.
Page 3, Table 1:
I presume that the blank space which you
have left in this table is intended to be filled in with additional tests which
Dr. Flinn has made upon subjects who were or are active.
Among this list
will have to be included some of those found at the Connecticut plant. Am I
correct in this assumption?
Page 5, Table 2:
In studying this table I was a little
surprised to note the variation in the constant - that is the drift increase
per microgram where the active source contained different quantities of radium.
I do not question your data, as I realize very well it is based upon the
figures you obained,But have you any explanation to offer as to the varation
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"ocrText": "October 2nd,1928.\nDr. Herman Schlundt,\nUniversity of Missouri,\nDepartment of Chemistry,\nColumbia, No.\nDear Dr. Schlundt:\nThe introduction as well as part one of the experimental\npart of our paper has been received.\nI have read your subject matter carefully several times\nand don't know as I can offer mach in the way of constructive criticism.\nThere are one or two points, however, which I wish to call to your attention\nfor further consideration: On page one of the introduction, toward the end\nof the first paragraph you state that an experienced operator can determine\nquantitatively one millionth of a microgram of radium.\nThis amount offhand\nseems almost beyond the range of accurate work, even with delicate instruments -\nfor instance, our experience indicates that it requires approximately five (5)\nmillimicrograns of radium element to cause the leaf to fall one division per\nsecond. The quantity indicated by you would be approxinately 1/50 of this\namount, which would mean a drift of approximately one dévision per minute for\nthe\nlarge chamber Lind electroscope - this it seems to me ie approaching the\nlimit for accurate W ork with this type of instrument.\nOn page 1 of part 1. experimental, at the bottom of page:\nWhat would you think of introducing in parenthesis the amont of Tadium which\nwe feel and experienced nan, working under carefully controlled conditions,\nwould give a positive test. As you know Dr. Flinn and I both feel that we\ncan positively detect quantities of less than 5 micrograms, and I can see\nno reason to expressing in a géneral way the amounts which up to the present\ntime\nwe\nfel\nwe can detect. I don't know as I would want to go down to a\nquantity of one microgram, but I do feel that wâth carefully controlled con-\nditions and repeated tests that a quantity of two micrograms could be detected.\nI merely suggest this for consideration.\nPage 3, Table 1:\nI presume that the blank space which you\nhave left in this table is intended to be filled in with additional tests which\nDr. Flinn has made upon subjects who were or are active.\nAmong this list\nwill have to be included some of those found at the Connecticut plant. Am I\ncorrect in this assumption?\nPage 5, Table 2:\nIn studying this table I was a little\nsurprised to note the variation in the constant - that is the drift increase\nper microgram where the active source contained different quantities of radium.\nI do not question your data, as I realize very well it is based upon the\nfigures you obained,But have you any explanation to offer as to the varation"
}