NOMOS. 21 



tricity would be conducted from the " conductor " 

 as fast as it was communicated to it, and there could 

 be no charge. It is the same also with the charging 

 of the Leyden jar ; only here we are able to seize 

 another link in the process. On connecting the 

 interior of the jar with the " conductor " of the 

 machine, the electricity is conducted by the chain to 

 the metallic lining of the jar, because " conductor," 

 chain, and lining are all conductors and all con- 

 tinuous. In this way the jar is charged. It is 

 charged because the lining is insulated by the glass 

 walls of the jar, just as the " conductor " is insulated 

 by its glass foot and the surrounding air. But the 

 electricity is not confined within the jar. On the 

 contrary, it has got into the coating of the jar, and 

 there is as much in the coating as in the lining. It 

 has got from the lining into the coating through the 

 glass, but not by conduction, for glass is a non-con- 

 ductor. The process by which it has got through 

 is called, not conduction, but induction. Nor is this 

 all. The jar, we find, could not be charged if it 

 were insulated. On the contrary, it must be in 

 connexion with the earth ; and so also must be the 

 rubber, from which the electricity is evolved by the 

 revolving plate or cylinder. In other words, there 

 must be no insulating media between the outside of 

 the jar and the rubber. In order to the charging of 

 the jar, indeed, the electricity must be able to act in 

 a circle, or from the rubber to the revolving plate 

 or cylinder, from this to the prime " conductor," 

 from this along the chain to the lining of the jar, 

 thence through the glass to the coating, and so 



c 3 



