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Show 52 Additional Notes. . . . umulated the accumulated electricity will pass off at electnc1ty lS ace ' . n· k b be fixed on the wire a much greater distance than Jf a meta IC uo and presented in its stead. . .· l 2. The same occut.s .f tl etallic pomt be fixed on the electi1sec 1 1e m ' . _ I t (l t11e fino·er of a person standmg on the ground be pl e-conc uc or, an ~ . . ff h o· t · sented to 1· t, t h e accnmu1 a t e c1 electric1ty w. tll pass o at a mu. c .0 rea er o· cl·t stance, anc1 ·m el eec1 ·11 0011 discharo·e Itself by commumcatm0 the WI o accumulated electricity to the atmosphere. 3. If a metallic point be fixed on the prime conductor, anc: the flame of a can dl e 1) e p1. esen tecl to it, on electrisin(o)' the con. ductor c1ther with vitreous or resinous ether, the flame of .the can.dle.ls ~lown from the point, which must be owin~ to. the electric fhucl m 1t~ p~ss ag e f the point carryino· along w1th 1t a stream of atmosphcn~ a1r. rom o . . 11 The manner in which the accumulated lectnc1ty so reac 1 ~ pa ~es off by a metallic point may be thus understoo<1; when a metallic pomt ·stanas erect from an electrisecl metallic plane, the accumulated electricity which exists on the extremity of the point, is attracted ~css than that on the other parts of the electrised surface. For the particle of electric matter immediately over the point is attracted by that point only, whereas the particles of electric matter over every other · part of the electrisecl plane, is not only attracted by the parts of the plane immediately under them, but aL o 1a~erall! ~y the circumj ace ~t parts of it; whence the accumulated e~ectrrc flmd IS pushed off at tlns point by that over the other parts bemg more strongly attracted to the plane. Thus if a light insulated horizontal fly be constructed of wire with points fixed as tangents to the circle, it will revolve the way contrary to- the direct' on of the points as long as it continues to be electri sed. For the same reason as when a circle of cork, with a point of the cork standing from it like a tangent, is smeared with oil, and thrown upon a lake, it will continue to revolve backwards in respect to the direction of the point till all the oil is dispersed upon the lake, as first observed by Dr. Franklin; for the oil being attracted to all the other parts of the cork-circle more than towards the pdinted tangent, that part over the point is pushed off and diffuses itself on ~he water, over which it passes without touching, and consequently without fricti on ; and thus the cork revolves in the contrary direction. Clzernical Tl1eory if Electricity and Magnetism. ss As the fl~me of a candle is blown from a point fixed on an electrised conductor, whether vitreous or resinous electricity is accumulated on it, it shows that in· both cases electricity passes from the point, which is a forcible argument against the mechanical theory of positive and negative electricity; because then the flame should be blown towards the point in one case, and from it in the other. So the electric fly, as it turns horizontally, recedes from the direction of the points of the tangents, whether it be clectrised with vitreous or resinous electricity; whereas if it was supposed to receive electricity, when electrisecl by resin, and to part with it when electrised by glass, it ought to revolve differc.1t ways; · which also forciably opposes the theory of positive and negative electricity. As an electrised point with either kind of electricity causes a stream of air to pass from it in the directiou of the point, it seems to affect the air much in the same manner as the fluid matter of heat affects it; that is, it will not readily pass through it, but will adhere to the particles of air, and is thus carried away with them. From this it will also appear, that points do not attract electricity, properly speaking, but suffer it to depart from them; as it is there less attracted to the body which it surrounds, than by _any other part of the surface. And as a point presented to an electrisecl conductor facilitates the discharge of it, ancl blows the flan1e of a candle towards the conductor, whether vitreous or resinous electricity be accumulated upon it; it follows, that in both cases some electric matter passes from the point to the conductor, and that hence there are two electric ethers; and thafthey combine or explode when they meet together, and give out light and heat, and occupy less space in this their combined state, like the union of nitrous gas with oxygen gas. IV. Accumulation qf ElectTic Ethers by Contact. The electric ethers may be separately accumulated by contact of conductors with nonconductors, by vicinity of the two ethers, uy heat, ancl by decomposition. |