Different lypes of 7 Rays from Radioactive Substances. 533 

 the observed ionization in air is 



Cb ^ 



i 1 = \ A 1 e~' xlX d.v = — l (<?-w«— e~* lb ), 



Ja Mi 



where a and h are the distances of the air-gaps from the face 

 AB, and /^ the absorption coefficient in air of the given 

 rays. 



If the chamber is filled with another gas the observed 

 ionization L will be 



h= \ 



b J^ 



A 2 e-^- x d,c= — (e-^ — e-^), 

 fi 2 



where A 2 is the ionization produced by the same rays in 



passing unit distance in the gas, and /jl 2 is the absorption 



coefficient of the rays in the gas at the given temperature. 



A 9 

 Hence . 2 , the ionization in the gas relative to air, is 

 Ai 



equal to 



A 2 _ i 2 / i 2 (e-^ a -e-^ b ) 



The total ionization in any gas will be 



I" 



Jo 



\e-' xr d.r = 



and the relative total ionization 



A2M1 

 A i/xo ' 



Table II. gives the results obtained with the soft rays q£ 

 radium D. 



Table II. 





i 



Relative ionization 2 ■ 



Relal ive total ionization 

 (air=l). 



CO, 



1-53 

 9-9 

 102 



092 

 0-99 

 1-23 



so., 



H,S 





It is seen that in the case of C0 2 and S0 2 the ionization 

 is approximately proportional to absorption, for which the 

 respective ratios are 1"G8 and 9 97. Therefore the relative 

 total ionizations do not differ very much from 1. 



