428 



Mr. G. N. Antonoff on the 



minute. (In figs. 3 and 4 the activities are expressed in 

 terms o£ the number of divisions per minute actually observed 

 in the electroscope.) 















Fig 



5. 

















'4 



























! 





13 

































a 

































ii 

































s " 



a 9 

 P-. 



i s 



■d 



5 v 



































— 























































r- 





























— 





























\ 

































\ 































\ 































I- 



A 































* 



V 







































-o- 























3S 4J> *S J-S JS 60 bi~ yo 



■$*- Thickness of aluminium, one foil equivalent to 

 about 05 cm. of air. 



The Position of the Neic Product. 



Since UrY is always present in purified uranium, it follows 

 that it must be derived in some way from that substance. 

 From a given quantity of uranium, only a small amount of 

 UrY could be separated at a time. It was calculated that 

 the electric effect due to UrY, under the experimental con- 

 ditions, was only about 1/60,000 of the total a ray effect due 

 to the amount of uranium from which it was separated. The 

 first separations by the ferric method remove most of the 

 product, and when the successive separations are made at 

 short intervals, the amount separated becomes much smaller. 

 It consequently follows that either this product is present in 

 very small quantities or the method of separation is almost 

 ineffective, In the latter case it is natural to suppose that 



