﻿Ionization of Metals by Cathode Rays. 



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i It appears possible to test these ideas by quantitative 

 measurements. If the change from state A to state B 

 consists in the removal of the gas and the exposure of the 

 metal, we should certainly expect in state B signs of an 

 ionization potential different from that in state A. If, 

 again, the changes beyond state B represent an increasing 

 difficulty of emergence of the liberated electrons, then we 

 should expect the ionization to be decreased in the same 

 proportion, whatever the speed of the incident rays, for the 

 speed of the liberated electrons is known not to depend upon 

 the speed of the primary rays. Unfortunately, the quanti- 

 tative experiments which have been made do not seem to 

 support either of these ideas. 



Vanation of the Ionization with Speed of the Rays. 



5. Fig. 2 gives some of the results which were obtained 

 in a series of experiments with copper, no changes in the 



Fig. 2. 



apparatus being mode during the series except those effected 

 by the discharge. These' results are typical of all those 

 obtained, except in a few* particulars, which will be noted 



