The enunciation alone of these results is sufficient to point out the consequences. 1st, Since the body B takes nothing from the electrified body A, it must possess within itself the principles of the two elec tricities which are developed in it by the influence of this body. 2dly, Since these two electricities disappear when the influence of the external body ceases, although they cannot escape into the group}, on account of the insulation of B, their proportions must be such, that, being left to themselves, they will mutually neutralize each other. Sdly, This neu tralization must operate without destroying these electricities, since they appear anew and quite en tire every time we submit the body B reduced to its natural state, to the influence of the electrified body A.
We are thus led to discover, that the principles of the two electricities exist naturally in every con ducting body, in a state of combination which neu tralizes their effects. This we shall henceforth call the natural state of bodies. We see also that fric. tion, which seems, at first view, a method of generat. ing the two electricities, serves only to disengage them from their mutual combination, and to render the one of them sensible by absorbing the other; and this is the reason, without doubt, that we constantly observe the rubbing and the rubbed body exhibit contrary electricities. In fine, since the sole influ ence of an electrified body presented at a' distance to another body in the natural state, forces the two electricities of that body to separate and to distribute themselves in such a manner that those of a different nature become the nearest to each other upon the two bodies, and those of the same nature the farthest, we must, in order to enunciate this fact, admit, that the electrical principles of a different name attract, and those of the same name repel, each other, according to laws which experience may perhaps enable us hereafter to•determine.
These observations lead to another important con sequence. When we begin to examine the electri. cal phenomena, we perceive that electrified bodies attract, or seem to attract, all the light bodies which ' are presented to them, without there being any ne cessity, for this purpose, of developing first the elec. tric faculty in these, either by friction or communica. tion. But we must now conceive, that this deve lopement goes on of itself, by the sole influence at a distance of the electrified body, on the combined electricities of the little bodies which we present to it ; so that, even in this case, the attraction, whether 'real or apparent, that we observe, does not take place but between bodies that are really electrified.
Moreover, the developement of the combined electricities in these circumstances is indispensable, in order that the attraction may take place ; for the latter is always the less vigorous as the former is effected with less facility. To be convinced of this, take two threads of raw silk, very fine, and of equal lengths. Suspend to them two little balls of equal dimensions, of which the one is of pure gum lac, and the other also ofgum lac, but gilt on its surface, or coated with tin-foil; these two pendulums being then placed beside each other, and at a small distance, bring near them a tube of glass or of sealing wax, rubbed and electrified ; you will see that the ball covered with metal, and on whose surface the de composition of the combined electricities goes on with facility, will be much more readily and more vi gorously attracted than the other. This one will not begin to be attracted till after a certain time, when the decomposition is finally effected on its sur face in spite of the resistance which its substance opposes to the motion of electricity; and, in like manner, when once the decomposition has taken place on this ball, its electrical state subsists even af ter we withdraw the electrified body. The first ball, although gilt, contracts also in this manner a perma nent electricity, because the resin of which we sup pose it composed, impregnates itself with the electri city developed at its surface ; and both of them are favoured in this respect by the contact of the air, which, under the influence of the electrified tube, tends, above all, to take away from them that of their combined electricities which is repelled by this body; while it has less effect on that of which the repulsive force is disguised by the tube's attraction. Hence we observe, in general,. that insulated bodies which have been for some time under the influence of an electrified body come, at last, to have an ex cess of electricity of the opposite kind, and of which the effects become manifest when we again withdraw them from the influence of this body.