70 nature's 



wire wound around it, across the poles of the 

 permanent magnet, and wrenched it away sud- 

 denly, when he observed a spark pass between 

 the ends of the wires. This would occur when 

 he approached the poles as well as when he 

 took it away. He discovered that the currents 

 were momentary and occurred at the moment 

 of approach or recession, and that the cur- 

 rents developed by the approach were of op- 

 posite polarity to those occurring at the reces- 

 sion. When the " keeper " was put on the 

 poles of the magnet it was magnetized by hav- 

 ing its molecular rings broken up and the 

 poles of the little natural magnets all turned 

 in one direction. During the time that the 

 molecules of the keeper are changing they are 

 in a dynamic or moving condition. By some 

 mysterious action of the ether between the 

 iron and the wire wrapped around it there is 

 a corresponding molecular action in the wire 

 that is dynamic for a moment only, and dur- 

 ina that moment we have the phenomenon of 

 an rlectric current. When the magnet and 

 soft iron are separated this molecular state of 

 strain is relieved and the molecules of both the 

 iron and the wire wound about it return to 

 normal, and in the act of returning we have 

 a dynamic or moving condition, resulting in a 

 current, only in the opposite direction. (See 

 Chap. VI.) 

 Now mount the permanent magnet in a 



