﻿.incited by tlie Alpha Rays from. Polonium. 



829 



It will be noticed that in these two last experiments with 

 the hydrogen the first reading was taken four minutes after 

 the pump was started, while in the three experiments with 

 the air the first reading was taken seven minutes after the 

 pump was started. The reason for this was that the pump 

 reduced the pressure of the hydrogen much more quickly 

 than the air, and it was desired to take the first readings 

 for both hydrogen and air at approximately the same 

 pressure. 



From the results given in the last two columns of 

 Tables VIII. and IX. the two lower curves of fig. 5 are 



Fiff. 5. 



is 



SO 75 



Time In Minutes 



US 



plotted, while the upper curve of fig. 5 is plotted from the 

 results given in the last two columns of Table V. The latter 

 curve pictures the way in which the rate of charging of the 

 fresh carbon electrode decreased with the time, while the 

 former curves show how the rate of charging of the fatigued 

 carbon electrode, which had been left in hydrogen at atmo- 

 spheric pressure, decreased with the time. 



It will be noticed that there is hardly any drop in the 

 lower curves, while the drop in the upper curve is considerable. 

 It will be seen also that the rate of charging of the fatigued 

 electrode, as indicated by the lower curves, is nearly the 

 same as the final value of the rate of charging of the Eresh 



