The Hammer Spinthariscope (ca. 1920s) |
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| This is a spinthariscope
manufactured by Hammer Laboratories of Denver Colorado and described as
"an instrument for demonstrating the atomic disintegration of
radium." It employs the "classic" design wherein the
radium source is attached to the tip of a wire/needle positioned just
above the screen of zinc sulfide (see photo above right).
Quoting the label on the box: " The Hammer Spinthariscope enables one to actually observe the effects of a single atom breaking loose from its parent element. To observe this interesting phenomenon necessitates that the eye be first adjusted, i.e., that the pupil be dilated by remaining in a darkened room 10 to 15 minutes. At night it is naturally adjusted. The radium, placed on the underside of the wire projector in the bottom of the instrument, disintegrates expelling atoms of helium (alpha rays) with a velocity of 12,500 miles per second. These atoms strike the phosphorescent zinc sulphide applied in the bottom producing brilliant flashes of light which are observed through the adjustable high power lens at the top. One milligram of radium, 1/28,000 of an oz., would produce for hundreds of years about 148,000,000 scintillations per second. For an hour or more before using, the Hammer Spinthariscope should be kept away from direct light since such light causes the phosphorescent material to become self-luminous, making it impossible to distinguish the scintillations caused by radium." |
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