Ask the Scholar

{
    "localId": "75729679",
    "label": "Letters Sent to Dr. S.C. Lind, October 20, 1939",
    "core": "doc",
    "dtoType": "document",
    "citationUrl": "https://catalog.archives.gov/id/75729679"
}

{
    "id": "75729679",
    "sourceUrl": "https://catalog.archives.gov/id/75729679",
    "contentType": "document",
    "title": "Letters Sent to Dr. S.C. Lind, October 20, 1939",
    "citationUrl": "https://catalog.archives.gov/id/75729679",
    "collections": [
        "Safety Light Collection",
        "Records Related to Radium Dial Painters"
    ],
    "iiifBase": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0003419_Page_1.jpg",
    "thumbnailUrl": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0003419_Page_1.jpg",
    "largeImageUrl": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0003419_Page_1.jpg",
    "imageCount": 3,
    "hasImages": true,
    "source": "import",
    "hasTranscription": false
}

{
    "url": "https://catalog.archives.gov/id/75729679",
    "naId": 75729679,
    "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_0003419_Page_1.jpg",
    "mediaId": "61cc2f324ef054a4",
    "ocrText": "October 20,1939\nDr. S. C. Lind,\nUniversity of Minnedota,\nMinneapolis, Minn.\nDear Dr. Lind:\nWie were glad to receive your letter of October 13th and shall\nattempt to give you the information requested.\n(1) The luminous material industry as a whole is not growing,\nsince the tendency on the part of many of the watch and clock concerns\nto cheapen qualityhas resulted in less demand for those dials. However,\nso far as the aviation field is concerned the industry is expanding quite\nrapidly due largely to the increased building program adopted by our owm\nGovernment.\n(2) There is probably a greater use for luminous dials today than\nduring the last World War due to the faot that many new type instruments\nhave beon developed which were not then known. In other words, there are\nmany more instruments per plane now than during the World War, and each\ninstrument is supplied with a luminous dial.\n(3) I cannot give you exact figures but the average small plane\nwould have 12 or 15 luminous treated dials. Aircraft like the \"Clipper\nShips\" and large Bombors have 3 sets of controls, and probably each ship\nhas from 60 to 75 luminous treated instruments. Aircraft such as Trans-\ncontinental planes with dual controls probably have anywhere from 24 to 50\ndials, depending on the type ship. There is no set rule, as each type ship\ndiffers from the other both in design and amount of equipmente\n(4) The use is not limited to military planes, as all commercial\ntransport planes are equipped with luminous treated dials.\n(5) In our opinion the present waz abroad will not incroase the use\nof luminous material in thi s countay unless there is a change in the present\nembargo law which will permit large scale purchases of aircraft by foreign\ngovernments. If this change is made, which is certainly indicated, there is\nno doubt but that the use of luminous material will be greatly enlarged.\n(6) No new worth while uses for luminous material have been developed\nduring the past fow years. However, both the Army and Navy have written\nSpecifications which require a higher grade material than previously used,\nand also require it to be applied with a much heavier application. So far\nas the industry is concerned, this alone will cause a large increase in volume.\n(7) Nesothorium is not generally used in luminous material at the"
}