476 ELECTRICITV. 



others with less degrees of rapidity. In some substances 

 called conductors it moves without any apparent obstruc- 

 tion, but in glass, resin and all bodies called non-conduc- 

 tors, it moves with great difficulty. This fluid exists in 

 two distinct forms called resinous and vitreous. Each of 

 these, when separate, have the general properties enu- 

 merated above ; but in relation to each other there is a 

 complete contrariety in their natures, so that when com- 

 bined together their powers are completely balanced and 

 neutralized, and all visible action ceases. This state of 

 union s is the natural state of electricity in all bodies. 



1. Theory of the excitation of the electric jluid. By 

 various causes this state of union may be disturbed. 

 When this is done, the powers before latent are called 

 forth by the separation of the fluids. The vitreous passes 

 in one direction and the resinous in the opposite, and 

 each existing thus in a separate state, produces its pecu- 

 liar effects. Thus, when glass is rubbed with silk, a por- 

 tion of the electricity of these bodies is decomposed. 

 The vitreous electricity goes to the glass ; the resinous 

 to the silk ; and then each can produce visible effects. 

 In the same manner when sealing wax is rubbed with 

 flannel a similar separation takes place. The resinous 

 electricity however enters the sealing wax and the vitre- 

 ous the flannel. 



2. Theory of electric attraction and repulsion. Each 

 of these fluids are supposed to be elastic, and consequent- 

 ly their particles repel each other. From very exact ex- 

 periments it has been ascertained, that the force of this 

 repulsion is inversely, as the square of the distance ; and 

 this repulsion is not interrupted by the intervention of 

 any other body. 



Although each fluid repels itself, each exerts a strong 

 attraction for the opposite species, and this attraction in- 

 creases with the diminution of distance, and in the same 

 ratio as the repulsion mentioned above ; that is, in the 

 inverse ratio of the square of the distance. This force 

 of attraction between the opposite electricities, like the 

 repulsion between the particles of the same kind, is not 

 affected by interposing any foreign body between them. 

 For example, if two pith balls resinously electrified, have 



