840 Prof. Barkla and Mr. Philpot : Ionization in Gases and 



The results of experiments similar to those on the simple 

 gases and vapours are given in Table III. 



Table III. 

 Showing relative total ionizations by corpuscular radiation 



in gaseous mixtures. 



Gas ionized. 



Total ionization due to 

 corpuscular radiation. 





100 

 102 

 1-50 

 1-26 

 1'48 



H„ 



CLHJBr 



Air (59'4)+C 2 H 5 Br (16'6) ,. 

 H 2 (59-4) +C 2 H 5 Br (166) ... 



Column 1 gives the gas or gaseous mixture ionized by 

 corpuscular radiation, and the partial pressures of the con- 

 stituents of a gaseous mixture ; column 2 gives the relative 

 total ionizations produced in these gases by the complete 

 absorption of the corpuscular radiations set up by homo- 

 geneous beams of X-rays. 



From the above values of the ionization in the mixture of 

 C 2 H 5 Br and air, we find that 52 per cent, of the radiation 

 was absorbed in C 2 H 5 Br and 48 per cent, in air. The masses 

 were about 51 per cent, and 49 per cent, of the whole 

 respectively. Thus as nearly as such experiments are capable 

 of showing, in a mixture of C 2 H 5 Br and air the absorption of 

 energy of corpuscular radiation by the two constituent gases 

 is proportional to the relative masses. There is no evidence 

 of appreciable selection. In the mixture of about 94 per 

 cent. C 2 H 5 Br and 6 per cent. E 2 , the calculated relative 

 absorptions of energy by the two constituents were about 96 

 per cent, and 4 per cent, respectively. This result shows a 

 large excess of energy absorption by the G 2 H 5 Br, though 

 as the above was based on a single observation and as the 

 absorption by hydrogen is very small, the possible error is 

 too great to allow us to form a conclusion as to the deviation 

 of the absorption by hydrogen from the density law. 



Ionization in Gases and Vapours hi/ Rontgen Radiation. 



The ionization produced in gases and vapours by homo- 

 geneous beams of Rontgen radiation was first studied by one 

 of us several years since. The results of experiments on 



