RONTGEN RAYS 



303 



with a fast cathode ray. The cathode rays from the concave 

 cathode C (fig. 2) were, by the application of a magnetic field 

 (at right angles to the plane of the paper), spread out into a 

 band along the anticathode A B. A small hole S in a lead 

 screen allowed some of the Rontgen rays produced to pass 

 through, and thus on the principle of the pin-hole camera a 



20 A-O 60 



ATOMIC WEICHT 



1 so 



220 



Fig. 1. 



spectrum of X rays was obtained on the remote side of the 

 screen. The rays along S D corresponded to the fastest-moving 

 particles which were incident at A, while along S E the rays 

 were those generated by the impact of the slowest-moving 

 particles at B. Narrow slits placed in the pencil of rays 

 allowed different parts to be examined by the radiomicrometer ; 

 it was found by the interposition of metallic screens that all 



