MU. K. K. SMITH ON THE NORMAL WKSTON CADMIUM CELL. 



413 



and a fourth for 5 days. The recovery of the first two cells is illustrated in figs. 13 

 and 14. It will be observed that the cell which was short-circuited for 1 minute 

 was right within a ten-thousandth of a volt 1 minute afterwards, but 40 minutes 

 were occupied in its recovery to 1 part in 100,000. The cell which was short- 



E M.F. 



roiaso 



I'OI825 



I'OI820 



roiais 



O 5 IO (3 



MINUTES 

 Fig. 13. Recovery curve of cell short-circuited for 1 minute. 



circuited for 5 minutes was nearly 1 in 1000 low 1 minute afterwards ; at the end of 

 the second minute it was 1 in 2000 low, and after 5 minutes it had recovered within 

 1 in 5000 ; about l hours were required for its complete recovery. The restoration 

 of the E.M.F. of the third cell was much slower; 1 minute after the circuit was 

 opened its E.M.F. was about O'l volt, which value it appeared to retain for 3 minutes. 

 The E.M.F. then changed suddenly from O'l to 0'85 volt, and at the end of 4 minutes 

 its voltage was 0'9. The recovery was then more gradual. Ten miuutes after 

 breaking the circuit the E.M.F. was O'OOGl volt below normal, 20 minutes afterwards 

 0'0028 volt low, and 5 hours afterwards it was low by 0-00040. It recovered within 

 1 in 10,000 in 24 hours, but 3 weeks were occupied in its complete recovery. 

 The cell which was short-circuited for 5 days had an E.M.F. less than 0'05 volt 

 o minutes after breaking the circuit, and its E.M.F. did not rise above 0'08 volt for 



