﻿'in Gaseous Mixtures J>u Rdntqen Radiation, 



329 



slowly led through the ionization-chamber and the ionization 

 determined as before. The mixture in the gas vessel was 

 then diluted by the introduction of more air, and from the 

 initial and final pressures the relative masses and partial 

 pressures of ethyl bromide and air in the ionizntion-cbamber 

 were again calculated. The process of dilution was repeated 

 a number of times with the result given in the upper portion 

 of Table IV. The original quantity of ethyl bromide intro- 

 duced was determined from the ionization produced in it, 

 thus 2*3 in column 7 was assumed correct for experiment 6, 

 and the others were based on this. 



Similar experiments were made with the long ionization- 

 chamber, though the range of pressures was not so great. 



Table V. 

 Ionization-chamber 11-5 cm. long, with Al window and end. 

 Radiation : the fluorescent X-radiation from A g (series K). 

 [Ionization was by the primary and all seconda^ rays except 

 Br X-radiation (series K).] 



Relative 



Partial 

 pressures of 



C a H 3 Br & 

 air in cm. of 



mercury. 



Observed 

 Ionization 

 in mixture. 



Ionization 



Ionization 

 due to air 

 in mixture 

 (air ends to 

 chamber). 



Additional 



Ionization 



weights of 

 1 C.,H 5 Br& 

 air. 



corrected 



for 

 absorption. 



Ionization 

 due to 

 C 2 H 5 Br. 



due to 

 C 2 H 5 Br 

 -r partial 













pressure. 



100 



76 



1-0 



1-0 



1-/; 









4-5 95-5 



0-94 75-06 



3-12 



315 



•99(1-A) 



2-29 



2-4 



8-8 91-2 



1:9 74-1 



5-46 



5-57 



■98(1-6; 



4-57 



2-4 



]6--) 83-5 



40 72-0 



9-58 



9-92 



•95(1-6) 



8-96 



2-2 



29-7 70-3 



71-5 68-35 



17-6 



18-7 



•91(1-6) 



17-72 



2-3 



39-7 60-3 



11-35 64-65 



25-0 



27-4 



'86(1-6) 



26-48 



23 



442 55-8 



13-2 62-8 



29-6 



329 



•84a -6) 



319 



2-4 



It is evident from the very small variations of the values 

 in column 7, that the additional ionization due to the ad- 

 mixture of ethyl bromide with air was, within the errors of 

 experiment, proportional to the quantity of ethyl bromide 

 present in the ionization-chamber, though the partial pres- 

 sures varied from <L cm. to 15 cm. of mercury, that is, for 

 mixtures containing various proportions of ethyl bromide 

 and air from 1 in 130 to approximately equal quantities 

 by mass. 



The possible error in the measurements of the ionization 

 due to small quantities of ethyl bromide was necessarily 

 greater than that in the values given for larger quantities 

 ' Phil. Mag. S. b\ Vol. 23. No. 134, Feb. 1912. Z 



