The story of Pittsburgh: Radium

Bibliographic data

Multivolume work

Identifikator:: 1831622599

Document type:: Multivolume work

Title:: The story of Pittsburgh

Place of publication:: Pittsburgh

Publisher:: First National Bank

Year of publication:: 1919-1930

Collection:: Economics Books

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Volume

Identifikator:: 1831623226

URN:: urn:nbn:de:zbw-retromon-239786

Document type:: Volume

Title:: Radium

Volume count:: Vol. 1, nr. 7

Place of publication:: Pittsburgh

Publisher:: First National Bank

Year of publication:: 1921

Scope:: [ca. 18] Seiten

Digitisation:: 2022

Collection:: Economics Books

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Chapter

Document type:: Multivolume work

Structure type:: Chapter

Title:: Radium

Collection:: Economics Books

be seething with scintillations or tiny flashes of light. These flashes are caused by the explosions of the atoms in the minute portion of real radium in the mixture. These atoms have been found to be so small that two hundred and fifty million of them would probably be required to cover one inch. As each atom explodes, a particle flies from it as a projectile from a gun. These particles are too small to be seen under the most powerful microscope. But scientists have found that when one of these particles is suddenly stopped by striking a crystal of zinc sulphide, the heat is sufficient to make a flash of light the eye can see. These are the flashes seen under a good reading glass. They occur at the rate of 200,000 a second on the average luminous dial on the average watch bought in commercial routine. It is the combined light of all the flashes of light seen under the reading glass that makes the light or glow that makes the dial visible in the dark without a reading glass. The brightness and durability of a Radium luminous dial depends on the number of these tiny flashes per seconds. The more Radium, the more flashes and the brighter the dial. But every flash means a blow upon a crystal of zinc sulphide. These crystalscannotstand theseblowsindefinitely. They break down under them, and when this happens, there are no more flashes and the dial loses its glow. The zinc has failed, not the Radium. Only one twenty-fifth of one per cent of any quantity of Radium disintegrates or is lost in a year. From a gram of Radium, a small thimbleful, there are about 184 billion projectile-like particles every second. Crystals of zinc sulphide would break down very quickly if exposed to such a bombardment. By reducing the percentage of Radium until the number of these particles flying from the exploding atoms of the radium on each dial, was about 200,000 per second, it has been found that the dial would have a brightness easily visible in darkness and for a period of about five years. This means that the quantity of Radium on the average dial cannot be more than about one millionth of a gram, and it is only such a minute quantity that is on the average I

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