﻿in Gaseous Mixtures by Rontgen Radiation, 323 



(belonging to another series in fact), we may conclude that 

 more ions were formed in SH 2 than in air for corresponding- 

 absorptions. We conclude, therefore, that about 30 per 

 cent, more ions are formed in SH 2 than in air by the com- 

 plete absorption of energy of soft X-radiation characteristic 

 of (Ju. 



On the other Land, it appears that the energy required to 

 produce an ion in S0 2 is slightly more than that required to 

 produce an ion in air. 



By similar reasoning we conclude that the energy of 

 X-radiation absorbed during the production of an ion in 

 ethyl bromide is considerably less than that in air, and even 

 in JSH 2 . 



The relative energies absorbed during the production of 

 equal ionizations in several gases are approximately : 



Air 1. 

 SH 2 -79. 

 !S0 2 1-08. 

 2 H 5 Br -70, or less. 



It should be pointed out that Langevin found for the ratio 

 in SH 2 and air the value *72. The other gases were not 

 experimented upon by him. Crowther obtained differences 

 of the same order for other gases, using heterogeneous beams 

 of X-rays, and Kleeman showed differences of like order in 

 the ionization, both by secondary corpuscular radiation 

 produced by X-rays and by a rays *. 



Ionization by Corpuscular Radiation. 



As the ionization produced in the mixtures of (SH 2 -r-0 2 ) 

 and (S0 2 + H 2 ) by X-rays were decidedly different, it 

 became a matter of interest to determine whether corpuscular 

 radiation would produce equal ionizations in these mixtures, 

 or if the relative ionizations would be the same as found 

 when the ionization was by X-rays. 



In order to test this, a very short ionization-chamber was 

 used so as to make the end effect large. It consisted of a 

 flat box 8 cm. square and 1 cm. in thickness, with both faces 

 of carbon. Thus, the window through which the rays 

 entered and the back surface upon which these rays fell were 

 of carbon, so that the corpuscular radiation from the two face's 

 was small. The gases consisting of elements of higher atomic 

 weight would on the whole lose in corpuscular radiation at 

 the boundary. This loss is, however, of no importance here. 

 * From Bragg-'s experiments. 



