OF GASES UNDER THE BECQUEEEL RAYS. 
519 
Diagram No. 3.—Polonium, prepared by Author. 
These experiments, as I have said, were made with polonium of my own pre¬ 
paration. Some of the experiments were repeated, using the more jDOwerful 
polonium preparation of Sir W. Crookes. 
The rates of leak at different pressures were determined, with the following 
result : — 
Pressure, 
millims. 
Time taken to pass over 
100 electrometer 
divisions. 
Current 
(arbitrary scale). 
; 
seconds. 
749 
22-4 
446 
1 53.5 
31-7 
316 
375 
45-8 
218 
170 
98-4 
102 
See diagram No. 4. 
The rate of leak is here sensibly proportional to the pressure tliroughout the entire 
