78 Mr. F. S. Spiers on Contact Electricity. 



static shield of aluminium that half encompasses the insulated 

 plate A, A. (It is not shown in the figure.) The shield has two 



Fig. 3. 



HYDftOGSA/ 



\ 



ELEVATION 



FRONT VIEW 

 OF PLATES 



slits shaped thus A that just slip over the heads of P and 

 Q. It was not necessary to completely shield A, A, as the 

 plate 0, C itself, which is of course earthed, serves as a partial 



