Recovery of Residual Charge in Electric Condensers. 587 



Fig. 6 corresponds to the case of J partition exposed. 

 Fig. 7 „ „ „ 2 partitions exposed. 



Fig. 8 ,, ,. „ 4 partitions exposed. 



The amount of surface-leakage can be seen from Table VII. 



Table VII. 





Partitions 

 exposed. 



Eatio : 



Surface Leakage 



Uranium Leakage' 



Percentage. 



i 



2 



4 



•0137 

 ' 175 



•015 

 •52 



•0118 

 •646 



7-8 

 29 

 1-8 





Tbe corrected values of the current when plotted against 

 time were found not to agree with an equation o£ the expo- 

 nential type, with which they should, were the actions going 

 on in an unstraining dielectric in agreement with the theory 

 of heterogeneous structure as given by Maxwell. 



An equation of the form 



d 



C = - — j — a 

 t + b 



was found to fit the experimental curves, figs. 6, 7, & 8 well. 

 In these figures the continuous lines are obtained from the 

 above equation, and the experimental values appear as circles. 



Galvanometer Method. 



The condenser used in these experiments was of about 

 5 microfarads. It was found to afford a very large residual 

 charge. Celluloid sheets, in conjunction with layers of paper, 

 laid on either side, were employed in its construction. This 

 gave a dielectric of avowedly heterogeneous structure, and 

 therefore might very well be expected to act in accordance 

 with the exponential law ; nevertheless it will be seen, from 

 the character of the curves obtained with it, that this is not 

 the case. 



The method of experiment was to charge the condenser 

 up to about 20 volts, discharge, and connect with a low- 

 resistance D'Arsonval galvanometer which was practically 



