98 Traces of Unity in the Various 



diminution of tenacity when the wire has been used for 

 some time, are only to be explained on the supposition 

 that the transmission of the electricity is attended by 

 some definite molecular change in the wire. And surely 

 the shattering or burning of a house, or other imperfect 

 conductor, by lightning, is only still more striking evi- 

 dence to the same effect. The case is one, indeed, in 

 which it is more than difficult to separate the idea of elec- 

 tricity from that of electrolysis. It would seem as if the 

 hypothesis of imponderable matter were as gratuitous 

 in one case as in the other. It would seem as if electricity 

 had as much to do with ponderable matter, and as little 

 to do with imponderable matter, as the force of heat or 

 the force of gravity even. Like either of these forces it 

 would seem to be resolvable into a mode of motion. 

 And, certainly, there is no want of agreement between 

 electricity and the other modes of physical force on the 

 score of correlation. Commencing with electricity as an 

 initiating force it is not necessary to go further than 

 ordinary electrical attraction and repulsion, as seen in 

 the electroscope, to see how the transition into motion 

 is effected by a direct path. How electricity directly pro- 

 duces heat is seen in the ignited wire, the electric spark, 

 and the voltaic arc heat intense enough to dissipate 

 every form of matter being given out in these instances. 

 In these instances, too, light and heat are inseparably 

 connected : and not less intimate is the direct con- 

 nection between electricity and magnetism, for, as is 

 shown in many familiar experiments with the coil and 

 needle, electricity cannot pass without the generation of 

 magnetism. And, lastly, by electricity it is possible to 

 obtain effects of analysis and synthesis which are not to 

 be got in any other way, and so electricity may be 

 looked upon as becoming chemical affinity. In point of 



