104 Dr. J. C Beattie on the Electrification of 



and was connected to the electrometer sheaths. The metal 

 cylinder was also connected to the sheaths. Air drawn 

 from the cylinder through the filter caused no deviation from 

 the metallic zero of the electrometer. When the lead was 



TO PUMP 



disconnected from the sheaths and joined to one terminal of 

 a battery, and the other terminal connected to sheaths, no 

 electrification of the air was observed with the lead at 

 potentials up to +95 volts. 



When the uranium was insulated in the metallic cylinder, 

 and this latter was of polished copper, the following results 

 were obtained : — 



(a) Uranium and copper both connected to sheaths and 

 air drawn from the cylinder through the filter. It was found 

 that an electrometer deviation of +005 of a volt per minute 

 of pumping was produced, the pump being worked at 12 strokes 

 per minute. 



(b) Uranium disconnected from the electrometer sheaths 

 and joined to one terminal of a battery, the other terminal 

 and the copper cylinder being connected to the electrometer 

 sheaths. 







Electrometer deviation in 



volts per minute of 



Uranium pumping 12 strokes 



kept at per minute. 



+ 2 volts . . . . + -36 



+ 10 „ 







. +-65 



+ 22 „ 







. +-53 



+ 45 „ 







. +-35 



+ 68 „ 







. . +-25 



+ 93 „ 







. +-235 



- 2 „ . 







. --32 



-10 „ 







. --53 



-22 „ 







. --40 



-45 „ 







. --25 



-68 „ 







. . --22 



-93 „ 







. --20 



