440 ANALOGIES OF 



taic electricity, evolved from a single pair, or 

 from a few series of large plates, with an inter- 

 posing liquid, differs greatly from that which is 

 obtained from a battery composed of the same 

 materials, but consisting of a great number of 

 smaller plates, and that the latter is equally dif- 

 ferent from the electricity of the atmosphere, or 

 that procured from a common machine. In fine, 

 that these differences are as numerous as the 

 circumstances are various under which the phe- 

 nomena take place. What then ? Shall we as- 

 sume the existence of an indefinite variety of 

 electric fluids ? Nothing could be more absurd, 

 or in opposition to the fundamental laws by 

 which they are governed. 



It has been supposed, that electricity is far 

 more subtile and refined than caloric, because of 

 the ease and rapidity of its passage through 

 metals and other conductors. This also is a 

 partial view of the subject ; for caloric passes 

 freely through mica, glass, and some other trans- 

 parent bodies, which arrest the electric fluid 

 when in the concentrated form. Nor is it true 

 that glass is altogether impervious to the electric 

 fluid. Compared with lac, it may be regarded 

 as a conductor ; for electricity produces attrac- 

 tions and repulsions through glass. If a small 

 pith ball be suspended within a glass jar by a 

 fine silk thread, it will be attracted by an elec- 

 trified glass tube on the outside. It is further 



