[KENNEDY] ACTIVE DEPOSIT FROM ACTINIUM 



TABLE II 



87 



Activity of Deposits in Air Dependent Upon Pressure. 



The next variation made in the experiments was to keep the elec- 

 trodes at a constant distance apart, 2 mms., and the salt at a fixed dis- 

 tance 11 mms. from them, while the pressure of the air was gradually 

 lowered and the activity of the deposits corresponding to different pres- 

 sures was measured. The range of pressures investigated was from 750 

 mms. to .5 mms. of mercury. Table III gives the results for air, and 

 Figs. VII, VIII, and IX, were drawn from them and illustrate the 

 manner in which the deposits occurred at the various pressures. The 

 curves for both electrodes, it will be seen, follow similar laws. The 



