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Show 62 Additional N()tes. IX. Of Galvanic Electricity. 1. The conductors of electdcity, as well as the nonconductors of it, have probably a portion of the vitreous. and resinous ether~ combined with them, and have also another portwn of these ethers chffu eel 1·ound them, which forms their natural or spontaneous adhesive atmospheres; and which exists in different proportions round them correspondent in quantity to those which are combined with them, but opposite in kind. . . These adhesive sponta11eous atmospheres of electnctty are shown to consist of different proportions or quantities of the electric ethers by :Mr. Bennet's Doubler of Electri~i~y, as mentioned in his wor~ called New Experiments on Electnc1ty, sold by Johnson. In tlu work, p. 91, the blade of a steel knife -\vas evidently, in his language, positive, compared to a soft iron wire which was comparatively negative; so the aclhesi ve electricity of gold, silver, copper, brass, bismuth, mercury, ~nd various kinds of wood and stone, were what he terms positive or vitreous; and that of tin and zinc, what he terms negative or resinous. Where these spontaneous atmospl1eres of diffused electricity surrounding two conducting bodies, as two pieces of silver, are perfectly similar, they probably do not intermix when brought into the vicinity of each other; but if these spontaneous atmospheres of diffused electricity are different in respect to the proportion of the two ethers, or perhaps in respect to their quantity, in however small degree either of these circumstances exists, they may be made to unite but with some difficulty; as the two metallic plates, suppose one of silver, and another of zinc, which they surround, must be brought into absolute or adhesive contact; or otherwise these atmospheres may be forced together so as to be much flattened, and compress each other where they meet, like small globules of quicksilver when pressed together, but without uniting. - This curious phenomenon may be seen in more dense electric atmospheres accumulated by art, as in the following experiment ascribed to lVIr. Canton. Lay a wooden skewer the size of a goose- Cltemical Theory of Electricity and Magnetism. 63 quill across a dry wine-O'lass and h let the ends of tl o 1' anot er across ad other wine-glass. 1em touc 1 each other as th 1. . h . ' line; call them X and y. ' ey le J n a onzontal external end of the skewei~ ~Pr~ach a rubbed glas_s-tube near the the t . ' u not so as to touch 1 t; then separate wo skewers by removing the wine-glasses further from e 1 o~her; and lastly, withdraw the rubbed o·lass-tube and th k ~CXl will no, b [I l o ' e s ewe1 v e ounc to possess resinous electricity which has b ~~n_;rally called nega~ive or minus electricity; and ~he skewer y ,:~1~ ound t_o _rossess VItreous, or what is generally termed positive or plus electnc1ty. The same phe~1omenon will occur if rubbed sealing wax be applied near to, but n?t m contact with, the skewer X, as the skewer X will tl:en be left Wt~h an atmosphere of vitreous ether, and the skewer y With o~e of resmous ether. These experiments also evince the existence of tw? electric fluids, as they cannot be understood from an idea of one bemg a greater or less quantity of the same material· as a vacuum of electric ether, brought near to one end of the skewer: cannot be conceived so to attract the ether as to produce a vacuum at the other end. . .rn th~s experiment the electric atmospheres, which are nearly of smu_lar kmds, do not seem to touch, as there may remain a thin plate of air between them, in the same manner as small globules of mercury may be pressed together so as to compress each other lono· before th . . ' b ey mtcrm1x; or as plates of lead or brass require strono·Iy to be pressed together before they acquire the attraction of cohesion· that is, before they come into real contact. ' 2. It is probable, that all bodies are more or Jess perfect conductors, as they have less or more of either of the electric ethers com. bined with them; as mentioned in Preliminary Proposition, No. VI. as they may then less resist the passage of either of the ethers throun·h them. v\ihence some conducting bodies admit the junction of th~e spontaneous electric atmospheres, in which the proportions or quantities of the two ethers are not very different, with greater facility than others. Thus in the common experiments, where the vitreous or resinous ether is accumulated by art, metallic bodies have been esteemed |