40 Dr. C. D. Cooksey on Asymmetry in the Distribution 



disks, already covered with one foil, in the vapour of heated 

 vaseline, and then laying them on the foil to be added. 

 One of these disks covered with one of the metals, say gold, 

 was then screwed between the two parts of each plate-bolder 

 and the holders placed over the ends of A with the aluminium 

 sides facing in. 



When the tube was turned on, and the wire C insulated 

 from the earth, there would be a motion of the gold leaf in 

 the electroscope E : toward one or other of the quadrants 

 depending upon whether the ionization in A or B was morf 

 intense. By a suitable adjustment of the screen F the 

 ionization in the two chambers could be made equal, when 

 there would be no motion of the gold leaf. After this 

 adjustment was made the tube was stopped, and the front 

 holder E reversed so that the gold side faced into A. 

 The leaf in the electroscope E 2 was then charged to a 

 potential of about 200 volts, and the tube again excited. 

 When the leaf, reached a certain division on the scale the 

 wire C was again insulated, and after the leaf in E a had 

 passed over a convenient number of scale-divisions the 

 tube was stopped. The position of the leaf in Ej was then 

 observed, and C connected to earth through a potentiometer, 

 and a sufficient potential applied to keep the leaf at its 

 observed position. Calling this potential a, we can take it 

 as a measure of the excess of ionization in A over that in B. 

 If e denote the ionization produced by the emergence 

 secondary rays from the gold, and e' that by the emergence 

 secondary rays from aluminium, we shall have 



c — e' = ka t 



where k is a constant. 



After this measurement was made the holder E was 

 turned back with the aluminium Eace in, aud the other 

 holder I reversed so that the gold faced in. The tube was 

 again excited, and the potential l> acquired by the leaf 

 in E! while the leaf in Eo passed over the same Interval as 

 before was measured. Denoting the ionization produced 

 by the incidence secondary rays Erom the gold by i, and 

 that by the incidence secondary rays from the aluminium 

 by i', we can write as before 



i-i' = kb. 



Letting c f /e — m, and i'/i = /i we shall have 



g/tsra/oQL— n) (1 - m)j 



where e/i is the ratio of the emergence secondary radiations 



