﻿Photo- Electric Fatigue. 

 Fur. 4. 



259 



Table III. 



Electrode after 



being exposed to 



light tor 5 minutes 



at Zero Potential. 



Recovered Elec- 

 trode, after a rest 

 of 5 minutes. 



Electrode after 



being exposed to 



light for 5 minutes 



at +2 volts. 



Fatigued Elec- 

 trode, after 

 exposure to light 

 for 5 minutes at 

 Zero Potential. 



Time. 



Charge. 



Time. 



Charge. 



Time. 



Charge. 



Time. 



Charge. 



15 sees. 



100 



15 sees. 



160 



15 sees. 



150 



15 sees. 



90 



30 „ 



120 



30 „ 



210 



30 „ 



190 



30 ,. 



125 



' 45 „ 



140 



45 „ 



225 



45 „ 



210 



45 „ 



140 



60 „ 



155 



60 „ 



250 



60 „ 



230 



60 „ 



150 



120 „ 



195 



90 „ 



265 



90 „ 



250 



90 „ 



175 



180 ,, 



230 



120 „ 



272 



120 ., 260 



120 ,. 



195 I 



240 „ 



248 









! 



180 „ 



220 



These tables and curves for aluminium show the same 

 characteristics as those for zinc. 



Experiments of a different nature were also made to test 

 the same points for aluminium. These were to measure the 

 photo-electric currents under different conditions. The current 

 was measured by joining the quadrants of the electrometer 

 through a very high resistance, thus using the electrometer 

 as a galvanometer. The current was measured, l>t. for the 

 fresh electrode. 2nd. after it had been exposed to light tor 



