MICHAEL FARADAY 253 



obtained magnetism by means of electricity; might it not be 

 possible to obtain electricity by means of magnetism? This 

 was one of Faraday's simple queries. Furthermore, the 

 phenomenon of influence is known, whereby an existing 

 electric charge produces a fresh charge; might it not be 

 possible to produce by means of an existing electric current 

 a fresh electric current? 



Guided by these ideas, Faraday prepared amongst other 

 apparatus, a double coil of two insulated wires, which were 

 wound alongside one another upon the same cylinder of 

 wood. The first wire he connected to a voltaic battery, the 

 second to a galvanometer. At first no motion of the gal- 

 vanometer needle could be observed; the wire in which no 

 source of current existed thus remained without a current, 

 in spite of the presence of the current in the other wire. 

 Even when a hundred and twenty cells were used for the 

 first wire, no greater success was obtained. Nevertheless, 

 Faraday was conscious of the richness of nature, which is 

 revealed to him who knows how to approach sufficiently 

 close to the unknown; it was his custom to pay attention to 

 everything that could in any way be observed during an ex- 

 periment. He noticed a slight deflection of the galvanometer 

 needle, not during the flow of the current in one of the wires, 

 but on the circuit being connected. Likewise, when the 

 current was interrupted, a second deflection of the galvano- 

 meter needle occurred, this time in the opposite direction. 



These phenomena were not of the kind expected, but 

 they were there; the new discovery had been made. The 

 battery current therefore 'induced' a current in the neigh- 

 bouring wire, although not a permanent current such as is 

 given by a voltaic battery, but only a short rush, such as is 

 given by the discharge of a Ley den jar, and this rush of 

 current occurred when the current was introduced into the 

 first conductor, and was repeated in the opposite direction 

 when the original current ceased. This fact, which 



