ELECTRICITY. 



n 



called electrics, or non-conductors, it 

 moves with great difficulty. Moreover, 

 as the phenomena appear to point out 

 the existence of two distinct kinds of 

 agencies, we may further assume that 

 there are two distinct species of electric 

 fluid, which we shall, for the present, 

 name the vitreous and the resinous 

 ('li'i'tricith's. They must each have, 

 when separate, the same general pro- 

 perties as have already heen enume- 

 rated ; but, in relation to each other, 

 there must be a complete contrariety in 

 their natures, so that when combined 

 together, their actions on the bodies in 

 their vicinity, or on the particles of 

 electric fluid contained in those bodies, 

 are exactly balanced ; and all visible 

 action ceases. It is in this state of 

 union, in which they perfectly neu- 

 tralize one another, that they exist in 

 bodies which may be said to be in their 

 natural state with regard to electricity. 



(42). Thus, then, may the problem 

 be solved, in which it is required 

 to conceive an agent, analogous, in 

 many respects, to other known agents, 

 and to assign to it such properties as 

 will, in their results, correspond to all 

 the observed phenomena. In order to 

 apply to it this latter test, we must 

 trace all the consequences which flow 

 from the suppositions w r e have made, 

 and strictly compare them with the facts 

 both as presented to us by nature, and 

 as resulting from experiment. These 

 facts, it will be recollected, are redu- 

 cible to those of excitation, attraction, 

 and repulsion, distribution, induction, 

 and transference. 



(43.) Excitation. From various 

 causes, of which the friction of sur- 

 faces is one, the state of union in 

 which the two electricities naturally 

 exist in bodies, is disturbed; their 

 latent powers are called forth by their 

 separation; the vitreous electricity is 

 impelled in one direction, while the resin- 

 ous is transferred to the opposite side ; 

 and each can now manifest its pecu- 

 liar energies. When accumulated in any 

 body, or part of a body, each fluid acts 

 in proportion to its relative quantity, 

 that is, to the quantity which is in excess 

 above that which is still retained in a 

 state of inactivity by its union with 

 electricity of the opposite kind. Thus 

 when glass is rubbed with a metallic 

 amalgam, a portion only of the elec- 

 tricities at the two surfaces is decom- 

 posed ; the vitreous electricity resulting 

 from this decomposition attaches itself 



to the glass ; the resinous, to the amal- 

 gam. What remains in each surface 

 undecomposed continues to be quite 

 inert, and has no other influence on the 

 phenomena, than being ready, on the 

 continuance of the decomposing action, 

 to furnish a fresh supply of both fluids 

 to the bodies in the vicinity. 



(44.) Distribution. Each of these 

 fluids, being highly elastic, their par- 

 ticles repel one another with a force 

 which increases in proportion as their 

 distance is less : and this force acts at 

 all distances, and is not impeded by the 

 interposition of bodies of any kind, pro- 

 vided they are not themselves in an 

 active electrical state. From the most 

 careful analysis of the phenomena, it 

 has been deduced that the exact law of 

 this force is the same as that of gravi- 

 tation, namely, that its intensity is in- 

 versely as the square of the distance. 



The mode in which the electricity 

 imparted to a conducting body, or to a 

 system of conductors, is distributed 

 among its different parts, is in exact 

 conformity to the results of this law, as 

 deduced by mathematical investigation. 

 But we reserve the examination of this 

 subject for a future chapter. 



While the particles of each fluid repel 

 those of the same kind, they exert an 

 equally strong attraction for the particles 

 of the other species of electric fluid. This 

 attraction, in like manner, increases with 

 a diminution of distance, and follows 

 the same law as to its intensity, namely, 

 that of the inverse ratio of the square 

 of the distance. This force, also, is not 

 affected by the presence of any interven- 

 ing body. 



(45.) Transference. Since the two 

 electricities have this powerful attrac- 

 tion for each other, they would always 

 flow towards each other and coalesce, 

 were it not for the obstacles that are 

 opposed to their motion by the non-con- 

 ducting properties of electrics. When 

 these obstacles are overcome, and a free 

 channel is open for the passage of the 

 electricities, they rush into union 

 with great force and velocity, producing, 

 in their transit and confluence, seve- 

 ral remarkable effects. After their 

 coalescence, their power seems to be 

 at once annihilated, or, more properly 

 speaking, it remains dormant, until call- 

 ed into play by the renewed separation 

 of the fluids. 



(46.) Attraction and Repulsion. The 

 repulsion which is observed to take 

 place between bodies that are insulated 



