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    "localId": "75723236",
    "label": "Letters Received to H.H. Barker, October 15, 1928",
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    "title": "Letters Received to H.H. Barker, October 15, 1928",
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        "Safety Light Collection",
        "Records Related to Radium Dial Painters"
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    "ocrText": "UNIVERSITY OF MISSOURI\nRECEIVED\nCOLUMBIA\nOCT 17 1928\nDEPARTMENT OF CHEMISTRY\nOctober 15, 1928\nMr. H. H. Barker\nUnited States Radium Corporation\nRADIC\n535 Pearl Street\nMAYERIAL CORP.\nNew York City, New York\nMy dear Howard:\nFirst of all let me thank you for your notes on progress of tests\nby the Commission, as per yours of October 11, 1928.\nEnclosed herewith is another installment of our report. I agree\nfully with you about getting published the material now in hand. To this end I\nhave\nfinished up the essentials of the theoretical part. Let us then try to assemble the\nmaterial now in hand and put it in final form.\nIn the meantime, could we not hold the fort by indicating in our\ntitle, as is quite often done, that this is the first contribution on the subject.\nThe title would then be:\nTHE DETECTION AND ESTIMATION OF PADIUM AND MESOTHORIUM IN LIVING PERSONS.\nI.\nThen on the page giving the outline insert this sentence just before the heading,\n\"GAMMA RAY MSTHOD\":\nThe experiments conducted on the radioactivity of excreta and the detection of radio-\nactivity in expired air by the scintillation method will be reported in a second con-\ntribution.\"\nSubject D, as appears in our notes, is H. H. Barker, with clothes\non, tested August 24, 1928. Perhaps this result should not be included after all.\nI hope that you and DI. Flinn will add to Table 1, page 3.\nNow let me take un some of the suggestions in your letter of\nOctober 2, 1928.\nl. Limit of Emanation Method: I have gone the limit in my state-\nment on page 1 of introduction but I hope not too far. In the Lind electroscope\n7 x 10- curies Radon - 7000 x10th grams, produce a drift of 1 division per second\nor 1 curie produces a net drift of 0.00014 divisions per second. In an instrument\nof smaller electrostatic capacity like a Wulf quartz fiber, one ullicurie would pro-\nduce a drift three to ten times as great which is about the same as the value\nwe\nfound for gamma ray instrument when 5 micrograms standard was used. When we tested\nyou on August 24, we found a net drift of 0.00033 divisions per second, which we re-\nport as 4 ug:\nBut I am not adverse to making this, \" a few micrograms in place\nof 1 microgram; but when you go down to 2 M for Wulf instrument by gamma ray method,\nplease remember the net drift increase will be only 0.00012 divisions per second."
}