The Röntgen Rays

Abstract

REFERRING to two letters in your last issue, p. 388, it is somewhat disconcerting to have Prof. Röntgen's original experiment—viz, the observation of shadows thrown on a barium-platino-cyanide screen—treated as a novelty. No one at all informed can have had the least scepticism concerning the probable observation of such shadows by Prof. Salvioni, though the sensational announcement made by some daily papers, that the eye had been made “actually to see” objects inside enclosures, was received, and is still received, with complete incredulity. A protected barium-platino-cyanide screen is extremely useful as a tester of the condition of an exhausted tube, and I have constantly used it as such, in imitation of Prof. Röntgen.