﻿of Ions made b// a, /3, y, and X Rays. 279 



place in the mm. next to the uranium oxide. The number of 

 ions lost by recombination will then be about five times 

 greater ; but it still remains a small fraction of the total 

 number received. 



In order to test still further whether the lack of saturation 

 was due to non-uniformity of the ionization, a thinner layer 

 of uranium oxide was used, having only about half the 

 ionizing power of the previous layer. 



The readings obtained are given in the following table, the 

 leak being taken for '22 seconds. 



Table II. 







xr u Deflexion 

 V olts per /1 v 



1 (eacn read my; 

 cm. v 4. i\ 

 repeated). 





1200 2565 2553 

 8 2002 2007 



1200 2593 2562 

 8 2001 2042 



Lack of 



saturation 

 22 per cent. 



It will be seen that the lack of saturation when 8 volts per 

 cm. were applied is the same as obtained with the thicker 

 uranium layer. The lack of saturation in both cases is there- 

 fore not due to non-uniformity of ionization. 



This establishes thus another similarity between the a rays 

 of uranium and radium. 



I now append some of the observations made with 

 X rays. 



The following table contains some of the observations made 

 with the aluminium chambers, in which the air was principally 

 ionized by primary rays. 



Table III. 



v ,, Deflexion 



N0Lts (adjustable 



l ?er cm ' chamber). 



Deflexion 

 (standard 

 chamber). 



Eatio. 



1200 1696 

 8 1703 



1200 1641 

 8 2117 



594 

 624 

 567 

 769 



286 

 273 

 2?9 

 275 



Lack of 

 saturation 

 5 per cent. 



20 1914 

 1200 1302 



20 1208 

 1200 1696 



671 

 446 



458 

 589 



285 T i , 

 000 -Lack or 



nno saturation 



goq 2 per cent. 



