MORSE AND SHUDDEMAGEN. — AN ALUMINIUM ANODE. 



379 



the two A curves were taken at 130 volts and 68 volts respectively. 

 Under these conditions the shape of the curve is a remarkable one. 

 It evidently takes time for the film to attain its optimum condition, 

 and this was to be expected. But the apparent capacity begins to 

 decrease again after a short time of charge, and this result was an 

 unexpected one. 



.02 .04 .06 .08 .10 .12 



time seconds 



Figure 8. 



Discharge curves at lower voltages for a very fully formed plate. Plate 

 formed at 140 volts, charged at 67 volts. 



We have found similar results for several plates, and there is no 

 reason to doubt that such curves correspond to real physical con- 

 ditions. 



The curve marked B may be taken as representative of another 

 series of measurements on other plates, and this curve we have also 

 found repeatedly. It corresponds to a difference in the previous history 

 of the plate under examination and apparently belongs to incomplete 

 or rapid formation. While the apparent capacity of an "A " plate has 

 its maximum value for a charging time of 0.03 to 0.1 second, that of 

 a "B" plate increases with charging time without passing through a 

 maximum, becoming asymptotic within a few seconds to the value 

 found for a very long time of charge. 



