Ask the Scholar

{
    "localId": "75723157",
    "label": "Letters Received to H.H. Barker, September 23, 1928",
    "core": "doc",
    "dtoType": "document",
    "citationUrl": "https://catalog.archives.gov/id/75723157"
}

{
    "id": "75723157",
    "sourceUrl": "https://catalog.archives.gov/id/75723157",
    "contentType": "document",
    "title": "Letters Received to H.H. Barker, September 23, 1928",
    "citationUrl": "https://catalog.archives.gov/id/75723157",
    "collections": [
        "Safety Light Collection",
        "Records Related to Radium Dial Painters"
    ],
    "iiifBase": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001450_Page_1.jpg",
    "thumbnailUrl": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001450_Page_1.jpg",
    "largeImageUrl": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001450_Page_1.jpg",
    "imageCount": 3,
    "hasImages": true,
    "source": "import",
    "hasTranscription": false
}

{
    "url": "https://catalog.archives.gov/id/75723157",
    "naId": 75723157,
    "levelOfDescription": "fileUnit",
    "recordType": "description",
    "ocrSource": "nara-archive"
}

{
    "seq": 1,
    "pageIndex": 0,
    "type": "photo",
    "url": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001450_Page_1.jpg",
    "mediaId": "add347788566893a",
    "ocrText": "UNIVERSITY OF MISSOURI\nRECEIVED\nCOLUMBIA\nSEP 27 1928\nDEPARTMENT OF CHEMISTRY\nSeptember 23, 1928\nTis\nIf\nen\nMr. H. H. Barker\nUnited States Radium Corporation\n535 Pearl Street\nNew York City\nMy dear Howard:\nYour letter and check covering balance of expense account\nhave just come to hand. I shall deposit check on Monday. This additionto\nmy bank balance may help to keep my standing with the bank at par. A minimum\ncash balance of $100.00 is now required by our looal banks.\nBeing interested in the quantitative aspect of our radium\nproblem, I am pleased to get your data on the radium content of excreta in the\nDunn case. Let us examine these data and make a few computations with a view\nof\ngetting\nsome idea as to the probable sensitiveness of this method for de-\ntecting radium in living persons. Altho the average of the figures gives a\ntotal daily elimination of radium by Miss Dunn of more than 0.010 micrograms,\nlet us take 0.010 micrograms (10 x 10-9 g) in our computations for just at\npresent we are merely concerned with the order of magnitude and not exact fi-\ngures. If we assume that the dry weight of the entire sample excreta had been\nused\nin\nmaking the radium determinations--an a 5 gram sample can be handled\nwithout introducing experimental difficulties- it is seen that the emanation\nfrom it will produce a drift of the leaf of a Lind electroscope of about 1\ndiv. per sec. since the constant of the instrument lies very close to 10 X 10-9\ngrams radium per div. per sec. Since the radium content of Miss Dunn turne d\nout to be about 100 micrograms, it follows that per microgram of radium the\nradium in dai ly excreta would produce a drift of about 0.01 div. per sec. an\namount well within the range of detection by the emanation method. On this\nbasis, the daily excreta from a subject containing about 5 micrograms should\ncontain sufficient radium to produce a net drift of about 0.05 div. per sec.-\na value fully 20 times the drift observed for a 5 microgram subject when the\ntests are made by the gamma ray instrument or with the Lind electroscope on\nexpired air. I realize full well that one must not generalize from data\nbased on a single case. One must also expect wide differences in the quanti-\nties of radium eliminated by different subjects or the same subject at differ-\nent times; nevertheless, this computation seems to indicate that the determi-\nnation of radium in excreta by the emanation method may turn out to be fully\nas delicate and positive as any of the other methods on which we have worked\nso faithfully. Is not our objective to find ways and means of detecting\nradium in living persons? It is largely on this basis that I proposed that\nwe proceed to make at least a few random determinations of radium with you as\nsubject."
}