Gaseous Mixtures oy Rontgen and Corpuscular Radiations. 837 



these by the molecular weights of the gases, we get numbers 

 proportional to 190, 174, and 170, which are the relative 

 masses of these gases required to produce complete absorption 

 of the corpuscular radiation. The agreement between the pro- 

 ducts for ethyl bromide and methyl iodide is very close, while 

 the difference between this and that for air amounts to about 

 10 per cent, of the whole. These results showthat the maximum 

 distance traversed by a corpuscle through these gases is ap- 

 proximately inversely proportional to the density of the gas. 



It will be observed that there were large differences 

 between the ionizations produced in the two vapours and in 

 air by the complete absorption of the corpuscular radiation, 

 the relative values being 1*0, 1*50, and 1*48 in air, ethyl 

 bromide, and methyl iodide respectively. 



It was evidently unnecessary to determine a series of 

 ionizations at various pressures for all gases, for beyond the 

 pressure just sufficient to completely absorb the corpuscular 

 radiation, the measured ionization was seen to be constant. 

 (See curves C, fig. 2.) Various gases were therefore intro- 

 duced into the ionization-chamber, two ionizations — those 

 obtained with carbon and with gold ends to the ionization- 

 chamber — were measured, and the difference was found. As 

 an example showing the order of agreement between the 

 results of different experiments, the following details of 

 observations are given. 



Table I. 

 Giving results of experiments on the relative total ionizations 

 produced by corpuscular radiation (that excited by 

 Sn X-rays, series K) in air and sulphur dioxide. 



Gas. 



Ionization in 

 chamber with 

 carbon ends. 



Ionization in 



chamber with 



gold ends. 



Corrected 

 ionization due 

 to corpuscular 



radiation. 



Total ionization in S0 2 

 by corp. radiation. 



Total ionization in air 

 by corp. radiation. 



SO.,,.. 



SO a 



so 2 



1-0 



7-46 



1-0 

 746 



1-0 



7-82 



9-77 

 15-90 



9-73 

 1551 



10-79 

 17-00 



8-80 

 8-G6 



8-76 

 8-27 



9-82 

 9-42 



•97 

 •95 

 •96 



This table requires little explanation. Column 4 gives the 

 difference between the value in column o corrected for 

 Phil Mag. S. 6. Vol. 25. No. 150. June 1913. 3 L 



