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{
    "localId": "75726987",
    "label": "Letters Sent, April 7, 1932",
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    "id": "75726987",
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    "contentType": "document",
    "title": "Letters Sent, April 7, 1932",
    "citationUrl": "https://catalog.archives.gov/id/75726987",
    "collections": [
        "Safety Light Collection",
        "Records Related to Radium Dial Painters"
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    "seq": 1,
    "pageIndex": 0,
    "type": "photo",
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    "ocrText": "April 7,1932.\nDr. S. C. Lind, Director\nUniversity of Minnesota,\nSchool of Chemistry\nMinneapolis, Minn.\nDear Dr. Lind:\nUnder separate cover we are shipping you various adhesives to\nbe used in connection with applying phosphorescent zine sulphide to glass\nsurfaces.\nYour letter does not specify whether you enticipate using this\nmaterial on the interior surface of a glass sphere or on a flat plate, but I\nrather infer that it is the former. If such be the case the procedure would\nbe to clean the glass ball thoroughly, place the desired amount of phosphor-\nescent zine sulphide in same and then add sufficient adhesive #7, mix with\nthe sulphide thoroughly, and then rotate the ball to give an even distribution\nover the surface - occassionaly blowing a little air into the ball to displace\nany saturated air inside the ball. We find this prodedure gives a very even\ndistribution of the zine sulphide inside the surface of a sphere.\nIn case you wish to apply the material to 8 flat gless plate, we\ndo not recommend the use of adhesive #7, as it dries entirely too rapidly.\nAdhesive #3, together with thinner for same, should be used for this purpose.\nPlace your zinc sulphide in & small crucible, add sufficient adhesive to give\nit sticking qualities, and then thinner to give it consistency to apply\nreadily. If we can be of any help in the preparation of your plates for you\nplease be assured that we shall be glad to do so.\nIn connection with the death of E. M. Byers, caused by the drink-\ninf of Radiothor, which was an aqua solution of radium and mesothorium:\nI have recently taken occassion to make a few simple calculations to determine\nthe amount of radon that one would have to ingest in order to have 8 sufficient\ndeposit of radium D in the system to act as a source of supply for polonium.\nlly calculations were based upon a device which is now being sold, and guzranteed\nto deliver 7000 Mache Units per day. If we make a hypothetical assumption that\nthe human system would act as a hermetically sealed unit, thereby retaining all\nradon ingested, we would find that after a period of 20 days the system would\ncontein approximately an equilibrium quantity of 40,000 Mache Units or 16 Micro\nCuries. Taking into consideration the breaking down of this quantity of radon\nwiththe formation of radium D, and the production of polonium from radium D,with\nalbna\nrays\nthe emission/from pólonitm, I figure that after a period of one year has\nelapsed, the alpha rays which would result from the polonium as a result of the"
}