﻿326 



Prof. Bark la and Mr. Simons on Ionization 



corpuscnlar radiation was negligible. The fluorescent 

 X-radiation from the aluminium was also found to affect the 

 results little if at all. (This was seen by covering the inside of 

 the ionization-chamber with a layer of lamp-black sufficiently 

 thick to absorb the fluorescent X-radiation from aluminium. 

 The ionization in air was not affected appreciably). 



As it was desired to compare the ionizations produced in 

 different gases by beams of the same intensity, corrections 

 were made for the screening of the deeper layers. Thus, if 

 T and I a are the total ionizations in a length / of gas and 

 air respectively, i and i a , the ionization coefficients (defined 

 as the ionization produced per centimetre path in a gas by a 

 radiation of unit intensity, all secondary rays being absorbed), 

 J the intensity of the incident beam, X and \ n the 

 coefficients of absorption of the radiation in 

 respectively, 



fas 



and air 



to 



J e 



• 9 ax 



dx 



\ L \ J 

 i a n-e-K.^ 



The results obtained are 



From this ~ was determined. 



la 



given in Table III. 



Table III. 

 Ionization-chamber 3-5 cm. long, with Al window and e nd. 

 lladiation : the fluorescent X-radiation from Cu (series K). 

 (Ionization was by the primary and all secondary rays.) 



Relative weights 

 of <J 2 H 5 Br and 



Partial pressures 

 or C 2 H 5 Bv and 



air in cm. of 



Observed 



Ionization 



in 



Ionization 



corrected 



for 



Ionization 

 due to 



Additional 

 Ionization 



Ionization 



due to 



C,H 5 Br 





merciuy. 



mixture. 



absorption. 



air. 



C.,H 5 Br. 



-=- partial 

 pressure. 



C 2 H,Br. 



Air. 



1 

 C 2 H 5 Br. i Air. 



10 



10 



1-0 



o-o 





o-o 



100 



0-0 j 76 



4-53 



95 47 



0-94 



75-06 



1-42 



1-43 



•99 



•44 



•47 



8-82 



9118 



190 



74-1 



1-80 



1 91 



■97 



•94 



•49 



16 o 



83-5 



400 



720 



2-86 



2-92 



•95 



197 



•49 



29-7 



70-3 



765 \ 68-35 



4-55 



4-75 



•90 



3-85 



•50 



397 



603 



11-35 6405 



5-83 



6-26 



■8Q 



5-40 



•48 



48-0 



52-0 



15-0 ; 61-0 



7-24 



7-84 



•81 



7-03 



•47 



