[ROBERTSON] 



INSULATED METALLIC CONDUCTORS 



119 



(h) Extent of the charge and variation in its magnitude with time. 



The charges in all the experiments were found to rise with varying 

 rates to their maximum values. These rates, however, were found to 

 be ver}^ greatly increased by the presence of radium bromide. Typical 

 sets of readings showing the rates at which the charge was acquired 

 with and without radium are given in Tables II and III. Other sets 

 of readings, illustrating various phases of the work are given in Tables 

 TI, IV, V, VI, VII and VIII, from which the curves shewn in Figs. 3, 

 4, 5, 6, 7 and 8 are plotted. 



TABLE IV. 



Tin No. 2 in tin No. 2. Without Radium. 



Time 



Deflection (millivolts). 



In agreement with McLennan and Burton, the writer found that the 

 extent of the charge varied little with the size of the cylinders, and wdth 

 the sign of the charge on the needle of the electrometer. A double com- 

 bination was made by joining the two inner tin cylinders together by 

 means of a piece of tin soldered to each, and also by joining in a similar 



