188 



THE DISCOVERY OF RONTGEN. 



rays from the cathode. The phosphorescence of the glass is only a 

 secondary appearance produced by the cathode beams. Before 

 1879, Goldstein, of Berlin, and Hittorf, of Munster, observed 

 these beams from the cathode, but they received the name of 



Crookes-light because, in a 

 report before the British 

 Association, Crookes did 

 not name Goldstein and 

 Hittorf, though he had 

 acknowledged their prior- 

 ity in the Chemical News 

 of the 30th of May, 1879. 

 The cathode rays, about 

 which further instruction 

 may be found in the 

 ■Vj Annaleii der Physik and 

 Chemie, 1895-1896 (Len- 

 ard's observations), are 

 different from the X rays 

 of Prof. Rontgen. The 

 X rays, which appear only 

 if the vacuum is driven to 

 S ^ S the highest degree, are not 

 ^ turned from their course 

 by an electro - magnet, 

 whereas the ordinary cath- 

 ode rays are so turned. 

 The cathode rays also 

 do not pass through the 

 glass of the globe, where- 

 as the X rays pierce the 

 glass, and spread in the 

 open air. The nature of 

 these Rontgen rays is not 

 yet quite known ; one 

 Fig. 16. would be inclined to be- 



lieve that they are ultra-violet light, but that they are not refran- 

 gible. The lens or the prism has no influence on the X rays ; they 



