208 ELEMENTS OF ELECTRICITY AND MAGNETISM. 



P, is left much more strongly charged than the plate AB. 

 The plate AB may itself be charged by moving it in front of a 

 point P 1 under the inducing action of CD as shown in Fig. 



-r T T -t 



Fig. 135. 



135. Under these conditions, the charges on AB and CD will 

 grow more and more intense until checked by the rapidly increas- 

 ing leakage from the surfaces of the plates. The negative charge 

 on CD, Fig. 135, after it has passed beyond the point P' t and 



Fig. 136. 



the positive charge on AB, after it has passed beyond the point 

 P, may be collected and used for any purpose. 



Figure 136 shows the essential features of a complete Wims- 



