438 POPULAR LECTURES AND ADDRESSES. 



supposed is constant, the loss will follow the 

 compound interest law so much per cent, of the 

 charge will be lost per second. Imagine now a 

 conductor, of perfectly constant resistance, to be 

 put between the ideal globe and the supposed 

 metallic walls of the room, and imagine the globe 

 to be connected with one of these electrometers 

 of which I shall say a word in conclusion by an 

 excessively fine wire going into the instrument, 

 and suppose the electrometer to indicate a certain 

 degree of potential, as we now call that subject 

 of electric measurement really discovered by 

 Cavendish in his measurement of electric capacity. 

 Now suppose that we are measuring the electric 

 value the potential of the charge in the globe 

 by an electrometer, then we shall see the electro- 

 meter indications decreasing the potential gradu- 

 ally goin^ down according to the logarithmic, 

 or compound interest law, in the circumstances I 

 h?ve supposed. But instead of this being carried 

 out, let us suppose the following conditions, which 

 we can imagine, although it would be impossible 

 for any mechanician to execute them. Let the 



