40 



TROWBRIDGE. 



ical Neivs under the date of February 5, 1896, which appeared 

 in the issue of February 15th of that weekly (Vol. LXXIII, 

 No. 7, page 192). The paper was entitled " A Convenient In- 

 strument for Visual Use in Diagnosis with the Rontgen Rays." 

 Another article, " Application of Rontgen Rays, the Appara- 

 tus and its Use," by the same writer, was published in the 

 American Jourual of tlic Medical Sciences for March, 1896, Vol. 

 CXI, page 251. In the second paper Professor Magie referred 

 to the instrument which he had devised, and called it the 

 "skiascope," as being a name appropriate to its uses. 



Fig. 12. Cryptoscope devised by Professor Salvioni. 



The first two illustrations which accompany this article are in- 

 tended to show the instruments w^iich have just been described. 

 In fig. 12, the ''cryptoscope," which was devised by Professor 

 Salvioni, is shown. The letters which represent the parts in the 

 cut are as follows : A, 3. tube 8 centimeters long, B, a lens used 

 to obtain an image of the screen, and C, a screen of fluorescent 

 material. 



Fig. 13, shows the ** skiascope" as first devised by Professor 

 Magie. In the figure, A represents a tube about four centi- 

 meters in diameter ; and C, the fluorescent screen. At B, the 

 tube was pressed tight against the face about the eye. T is 

 meant to indicate a Crookes tube. The third cut, fig. 14, which 

 shows the Edison fluoroscope, has been drawn for the purpose 

 of comparison. Although this apparatus is quite familiar to 

 many, it is described, and its uses are outlined, because it is the 

 form of '' fluoroscope " which has been most generally used since 

 the discovery of Rontgen rays. 



