Maltese Cross Crookes Tube (ca. 1910-1940) |
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| This type of tube was invented in the 1880s by William Crookes during his investigations unto the nature of cathode rays (electrons). The tube's most distinctive feature is the Maltese Cross that could be laid flat or stood up so that the cathode ray beam impinged upon it. When a high voltage was applied, the flat end of the tube fluoresced (and although it wasn’t yet recognized, emitted x-rays). If the cross was in the cathode ray beam, its shadow appeared on the end of the tube. This indicated that cathode rays traveled in straight lines and that they could be stopped by a thin piece of metal. |
Shadow image of cross on end of tube |
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It might have been that Crookes used a Maltese Cross because the pronunciation of his name is not that different from the pronunciation of the Latin word for cross: crux. The example shown here was manufactured by the Otto Pressler company of Germany. |
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