162 Prof. A. de la Rive’s Memoir of 
mentary but in an opposite direction, is developed at the moment 
when the magnet is withdrawn. Here, therefore, was realized 
that production of electricity by magnetism which Faraday 
had long been seeking, convinced, as he was, that, as electricity 
produces magnetism, magnetism in its turn must produce elec- 
their number, which appears to be very considerable. 
man 
