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Show 58 Additwnal Notes. VII. The spark from the conductor, and qf electric light. When either the vitreous or resinous electric ether is accumulated on an insulated conductor, and an unin ulated conductor, as the finger of an attendant, i applied nearly i11 contact with it, what happens? The attractive and repulsive powers of the accumulated electric ether pa s through the nonconducting plate of air, and if it be of the vitreous kincl it attracts the resinous electric ether of the finger towards it, aucl r' epels the vitreo~s electric ether of the finger from it. Hence there exists for an instant a charged plate of air between the finger and the prime conductor, with an accumulation of vitreous ether on one· side of it, and of resinous ether on the other side of it; and lastly these two kinds of electric ethers suddenly unite by their powerful attraction of each other, explode, and give out heat and light, and rupture the plate of nonconducting air, which separated them. The rupture or disjunction of the plate of air is known by the sound of the spark, a of thunder; which shows that a vacuum of air was previously produced by the explosion of the electric fluids, and 'a vibration of the air in consequence of the sudden joining again of the sides of the vacuum. The light which attends electric sparks and shocks, is not accounted for by the Theory of Dr. Franklin. I suspect that it is owing to the -combination of the two electric ethers, from which as from all chemi< cal explosions both light and heat are set at liberty, and because a smell is said to be perceptible from electric sparks, and even a taste ·wh1ch must be deduced from new combinations, or decompositions, as in other explo ions: add to this that the same thing occurs, when electric shocks· are passed through eggs in the dark, or through water, a 1 uminous line is se'en like the explosion of a train of gunpowder; lastly, whether light is really produced in the passage of the Galvanic electricity through the eyes, or that the sensation alone of light is perceived by its stimulating t~1e optic nerve, ha not yet been investigated; but I suspect the former, as it emits light from its explo- ·Chemical Tlwmy rf Elect1·icity and Magnetism. sg sian even in passing through eggs and through water, as mentioned above. VIII. Tile s7wclc f 'ronz the coated jar, and qf electric condensation. 1. 'Vhen a gla jar is coated on both sides, and either vitreous or ~esinou electricity is thrown upon the coating on one side, and there IS a commu~1ication to the ~arth from the other side, the same thing happens as 1u the plate of ::ur between the fino·er and prime conductor above described; that is, the accumulated e~ctricity, if it be of the vitreou kincl, on one coating of the glass jar will attract the resinous part of the electricity, which surrounds or penetrates the coatin<>' on the other side of the jar, and also repel the vitreous part of it; 0 but this occurs on a much more exten ive surface than in the in tance of the plate of air between the finger and prime conductor. The difference between electric sparks and shocks consists in this circumstance, that in the former the insulating medium, whether of air, or of thin glass, is ruptured in one part, and thus a communication is made between the vitreous and resinous ethers and ' they unite immediately, like globules of quicksilver, when pressed forcibly together: but in the electric shock a communication is made by some conducting body applied to the other extremities of the vitreous, and of the resinous atmo pheres, through which they pass and unite, whether both sides of the coated jar are insulated, or only one side of it. And in this line, as they reciprocally meet, they appear to explode and give out light and heat, and a new combination of the two ethers is produced, as a r siduum after the explosion, which probably occupies much less space than either the vitreous or resinous ethers did separately before. At the same time there may be another unrestrainahle ethereal fluid yet unobserved, given out from this explosion, which rend oak trees, bursts stone-walls, lights inflammable substances, and fuses metals, or dis ipates them in a calciform smoak, along with which great light and much heat are emitted, or these effects are produced by the heat and light only thus set at liberty by their synchronous and sudden evolution. |