OF GASES UNDEE THE BECQUEREL RAYS. 
517 
Pressure, 
millims. 
Time taken to 
pass over 100 scale 
divisions (mean of 5 
observations). 
Current 
(arbitrary scale). 
719 
21-4 
467 
517 
26-1 
383 
313 
41-6 
240 
121 
101-0 
83 
The results are plotted on diagram No. 2. Here the absorption of the radiation by 
the air is quite perceptible. The current is sensibly proportional to the pressure for 
pressures less than half that of the atmosphere. In comparing different gases, this 
limit of pressure was not exceeded. 
Diagram No. 2.—Radium. Easily absorbed Radiation. 
Pressure, mrn. of Mercunj. 
