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UNIVERSITY OF MISSOURI
COLUMBIA
DEPARTMENT OF CHEMISTRY
January 21, 1931
JAN 23 1931
Mr. H. H. Barker
United States Radium Corporation
535 Pearl Street
New York City, New York
My dear Barker:
Naturally when it came to the question of the
quantity of radium that can be detected in a living subject by
the gamma ray method, both Dr. Lind and myself called for the
experimental data from which the calculations were made. Let
me give you an example: The record shows that the normal drift
of the instrument was two divisions in 40 minutes;with the sub-
ject under test the observed drift was two divisions in 32 min-
utes. The constant of the instrument is assumed as .00015 +.
The natural drift in this case is .00083 and the observed drift
with subject is .00104, leaving a difference of .00021 from which
it shows that the subject contains about 1.4 micrograms of radio-
active substance.
As I recall it most of the dial painters who have
worked since 1926 contained but very small traces of radium and
in many cases practically none. The occasional high values such
as 6 to 8 micrograms are very limited and it seems to me must be
due to some accidental occurrence.
During the next few days I expect to receive from
Dr. Leake who succeeded Dr. Thompson on the Committee, a revised
copy of the report and I shall be glad to mail this to you for
reading.
As I recall it now the statistical curve for the
increase of activity in the workers with time runs about one to
two micrograms per year averaged
over all the workers.
The transfer-press method of applying luminous
paint is considered a little more hazardous than regular dial
painting because of the larger quantities of paint used at any
one time. There is more danger of dust because as now in opera-
tion the excess paint after drying is scraped off and thus finds
its way into the air in the immediate vicinity of the workers.
I expect to write to you again within the next days. Our
semester examinations are now in progress and so we are very
busy with the closing work of the semester.
Sincerely yours,
Thig letter was dictated
about a week ago-
Herman Schlundt
HS:AS
Hermen Schlundt.
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"ocrText": "UNIVERSITY OF MISSOURI\nCOLUMBIA\nDEPARTMENT OF CHEMISTRY\nJanuary 21, 1931\nJAN 23 1931\nMr. H. H. Barker\nUnited States Radium Corporation\n535 Pearl Street\nNew York City, New York\nMy dear Barker:\nNaturally when it came to the question of the\nquantity of radium that can be detected in a living subject by\nthe gamma ray method, both Dr. Lind and myself called for the\nexperimental data from which the calculations were made. Let\nme give you an example: The record shows that the normal drift\nof the instrument was two divisions in 40 minutes;with the sub-\nject under test the observed drift was two divisions in 32 min-\nutes. The constant of the instrument is assumed as .00015 +.\nThe natural drift in this case is .00083 and the observed drift\nwith subject is .00104, leaving a difference of .00021 from which\nit shows that the subject contains about 1.4 micrograms of radio-\nactive substance.\nAs I recall it most of the dial painters who have\nworked since 1926 contained but very small traces of radium and\nin many cases practically none. The occasional high values such\nas 6 to 8 micrograms are very limited and it seems to me must be\ndue to some accidental occurrence.\nDuring the next few days I expect to receive from\nDr. Leake who succeeded Dr. Thompson on the Committee, a revised\ncopy of the report and I shall be glad to mail this to you for\nreading.\nAs I recall it now the statistical curve for the\nincrease of activity in the workers with time runs about one to\ntwo micrograms per year averaged\nover all the workers.\nThe transfer-press method of applying luminous\npaint is considered a little more hazardous than regular dial\npainting because of the larger quantities of paint used at any\none time. There is more danger of dust because as now in opera-\ntion the excess paint after drying is scraped off and thus finds\nits way into the air in the immediate vicinity of the workers.\nI expect to write to you again within the next days. Our\nsemester examinations are now in progress and so we are very\nbusy with the closing work of the semester.\nSincerely yours,\nThig letter was dictated\nabout a week ago-\nHerman Schlundt\nHS:AS\nHermen Schlundt."
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