The spinthariscope used in scientific investigations was quite different from what Crookes had described in The Chemical News-a microscope, not a hand-held lens, was employed to visualize the scintillations. But the spinthariscope was far more-it was the first radiation counter! Earlier devices for measuring radiation (e.g., photographic plates, electrometers, electroscopes) were integrating instruments, but the spinthariscope detected individual decay events!
Children received spinthariscopes as presents - no doubt leading to many a career in the sciences.Įven today, most of us think of the spinthariscope as a childhood toy (e.g., the Lone Ranger Atom Bomb Ring). Gentlemen and ladies carried them in pockets or purses, ready to bring them out at an opportune moment and demonstrate the latest in atomic instrumentation. But it was the spinthariscope, the piece de résistance, that lit up that star-studded evening (Keller 1983). recent developments in wireless telegraphy, poisonous sea-snakes, and archeological expeditions in Crete. The creme de la creme of the social and scientific elite were there to rub shoulders and take in the spectacular exhibits on display, e.g. Such a miraculous instrument required a suitably wondrous name and Crookes obliged: "I propose to call this little instrument the Spinthariscope from the Greek word scintillation." To Lawrence Badash (1964), it was only natural that the eloquent Sir William chose the name from Homer's Hymn to the god Apollo.Ĭrookes' spinthariscope made its first public appearance at a special soiree of the British Royal Society, May 15, 1903. Crookes described the effect of such an adjustment as follows: "on bringing the radium nearer the screen the scintillations become more numerous and brighter, until when close together the flashes follow each other so quickly that the surface looks like a turbulent, luminous sea." The position of the radium, affixed at the end of a needle, could be adjusted by means of a thumbscrew. As he described its construction in The Chemical News (Crookes 1903): "fit the blende screen at the end of a brass tube with a speck of radium salt in front of it…about a millimeter off,…a lens at the other end." Inspired, Crookes built an amazingly simple device that provided a convenient way to view these scintillations. And what he saw astonished him! Rather than the expected uniform glow, he observed discrete flashes of light-each flash produced by an individual alpha particle!
Eager to locate and recover it, Crookes inspected the screen under a microscope. But accidents happen, and Crookes spilled some of the radium. Sir William Crookes, the very picture of Victorian elegance, was entertaining himself by observing the fluorescence that alpha rays from radium produced on a zinc sulfide screen (Romer 1960). This article originally appeared in the Health Physics Society Newsletter.