^60 LECTURE LIII. 



to be materially concerned in the great phenomena of the universe; but in 

 the common neutral state of all bodies, the electrical fluid, which is every 

 where present, is so distributed, that the various forces hold each other 

 exactly in equilibrium, and the separate results are destroyed ; unless we choose 

 to consider gravitation itself as arising from a comparatively slight inequality 

 between the electrical attractions and repulsions. 



The attraction of the electric fluid to common matter is shown by its com- 

 munication, from one body to, another, which is less copiously supplied 

 with it, as well as by many other phenomena; and this attraction of the 

 fluid of the first body, to the matter of the second, is precisely equal to its 

 repulsion for the quantity of the fluid, which naturally belongs to the secon<l, 

 so as to saturate the matter. For the excess or deficiency of the fluid in the 

 first body does not immediately produce either attraction or repulsion, 

 so long as the natural distribution of the fluid in the second body remain* 

 unaltered. 



Since also two neutral bodies, the matter which they contain being saturated 

 by the electric fluid, exhibit no attraction for each other, the matter in 

 the first must be repelled by the matter in the second; for its attraction for 

 the fluid of the second would otherwise remain uncompensated. We are, 

 however, scarcely justified in classing this mutual repulsion among the 

 fundamental properties of matter; for useful as these laws are rn explaining 

 electrical appearances, they seem to deviate too far from the magnificent 

 simplicity of nature's works, to be admitted as primary consequences of the 

 constitution of matter: they may, however, be considered as modifica- 

 tions of some other more general laws, which are yet wholly unknown 

 to us. 



When the equilibrium of these forces is destroyed, the electric fluid is put 

 in motion; those bodies, which allow the fluid a free passage, are called 

 perfect conductors; but those which impede its motion, more or less, are 

 nonconductors, or imperfect conductors. For example, while the electric 

 fluid is received into the metallic cylinder of an electrical machine, its ac- 

 cumulation may be prevented by the application of the hand to the cylinder 

 which receives it, and it will pass off through the person of the operator to 



