[Annals X. Y. A. S., XI., Xo. 2, pp. 29 to ;^S, March 30, 1898.] 



AN "X-RAY detector;' FOR RESEARCH 



PURPOSES. 



C. C. Trowbridge. 



(Read November 2, 1896.) 



The " X-ray Detector" is an instrument which has been de- 

 signed and constructed for the study of fluorescence caused by 

 Rontgen rays. It is a new form of the " fluoroscope," that ap- 

 paratus which has been so generally used for the observation of 

 the shadow images cast by these rays. 



In its construction several devices were used to make it par- 

 ticularly suitable for research purposes, and a name has been 

 given it, in order that it might not be confused with the types 

 of the instrument previously constructed. 



A description of the '* X-ray Detector" will be more clearly 

 understood, if a brief reference is first made to the original forms 

 of the "fluoroscope." 



Shortly after the discovery of the X-rays, several investiga- 

 tors independently perfected the method of using the fluores- 

 cent screen, employed by Professor Rontgen in his first experi- 

 ments with these rays, and devised an instrument for the study 

 of the shadow pictures of this recently discovered form of en- 

 ergy. 



Professor E. Salvioni, of Perugia University, Italy, and Pro- 

 fessor William F. Magie, of Princeton College, in this country, 

 appear to have been the first to construct and use such appara- 

 tus. Both were apparently working on similar lines of research 

 and developed the same idea independently of each other. 



In a paper read before the Perugia Medico-Chirurgical Society 

 on February 5, 1896, Professor Salvioni gave an account of 

 an instrument, devised by himself, for the observation of X-ray 

 shadow effects, in which he made use of the fluorescent screen. 



(29) 



