2 MORRIS-AlREY & Spencer, Capacity of a Condenser. 



connected to a condenser in the manner shown in the 

 diagram. If P is connected to Q, the plates of the con- 



Q 



Fig. I. 



denser become charged, and a quantity of electricity 

 equal to EC passes through the galvanometer. If P is 

 joined to S, the condenser is discharged. On performing 

 this operation n times per second, a quantity of electricity 

 equal to nEC passes through the galvanometer. If the 

 time of swing of the galvanometer needle is great com- 

 pared with the time of vibration of P, the galvanometer 

 shows a permanent deflection corresponding to the passage 

 through it of a current of strength nEC. 



Now replace the condenser and key by a resistance R., 

 adjusted so that the galvanometer deflection is the same 

 as that obtained with the condenser in circuit. The 



