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clear, viz. that the fire in the coated wire is fupplied in a manner fimilar to the water in the pipe.

218. If the finger be continued at a small distance from the end f of the coated wire, in the former Experiment, the fire escapes to it and is continued in a conftant ftream, which paffeth thro' the Person into the Earth, as thro' a proper vehicle, and a fupply is vifible between the prime Conductor and the other end of the coated Wire, that is, between d and e, where a constant stream appears alfo : So that Metals act as Conductors of Electricity, in like manner as the Refervoir and Pipe conduct the Water.

219. N. B. If any one can still doubt, whether the Fire really paffeth through the Person into the floor, the truth may be proved by his standing on the Refin-cake, where, when he is electrifed, not the leaft fpark appears, tho his finger be brought ever fo near the end of the coated Wire, the communication with the Earth being then intercepted by means of the Refin-cake on which the Perfon is fupported.

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CHA P. X.
X.

PART I.

SECTION.

220.

Concerning the fimilarity of electrical Fire, and the Fire of Lightning; and of electrifing plus and minus: With Remarks on deftroyed and restored Equilibriums.

I

Have before taken notice how greatly the World, and paricularly Electrici ans are indebted to the worthy and indefatigable Dr. Franklin for the ufeful hints in that hitherto uncultivated branch of Philofophy, Electricity.

many

221. How early did he discover the extenfive effects of the electrical Agent, and that the Fire difcoverable in electrical Experiments was the fame with that of Lightning, by inventing fuch decifive Experiments, which put it paft all future difpute; fuch as his electrical Kite, at p. 106. of his Letters on Electricity; his pointed iron Rods at the tops of lofty Buildings, with other useful hints concerning what he calls pofitive and negative Electricity, and reftoring of destroyed Equilibriums?

222. Were we but equally industrious to examine and pry into that abftrufe Phænome

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non of Nature, we had probably long before this time made very confiderable advances and advantageous Improvements in that way: As

223. Firft. Since the Fire exhibited in elec trical Experiments and that of Lightning prove to be one and the fame thing, we are no longer in any doubt, (as it feems we were) whether Fire be a permanent Principle or not, or whether we can generate and destroy it at pleasure juft as we do Heat.

224. Surely the judicious Philofopher will never let prejudice in favour of former Opinions fo far prevail with him as to deny it to be Fire, merely because it neither burns nor exhibits. any Light, fince we find the largest quantity of Fire breaks out, and with the greatest violence, from the darkest Clouds. Would it not then favour much of prejudice to former Opinions, Terms, and Definitions, to hear any one infift that it is not Fire till the Light appears, and as foon as that is over, that the Fire is annihilated notwithstanding the Principle remains? Can any thing appear much more like invincible prejudice than to find ingenious Men, after racking their brains, roundly affert, that it is as improper to call the electrical matter (and confequently the matter of Lightning) by the name of Fire, as it would be to call Air by the name of Sound? and that a principal reason for it was, becaufe it was not agreeable to the Chymifts Senfe of the word, tho' it was next to impoffible for the Chymifts themfelves to form

any

any just Idea of the nature of true Fire, before this fluid was difcover'd. Was it very likely that they or any one elfe fhould imagine that true Fire was fo much in the form of Air, as we now find it to be?

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225. Secondly. If the Fire of Lightning and that of Electricity be the fame, it would be but natural to suppose that each was supplied from the fame fource, and that the means by which it prevails in both, should have some remarkable affinity and agreement.

226. It appears by undeniable evidence, Sect. 194. 195. &c. that the great Fountain, from whence the electrical Fire is obtain'd, is the Body of the Earth.

227. And from the general Confent of the moft eminent Naturalifts, the Fire of Lightning 'proceeds from the fame fource.

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228. Sir Ifaac Newton, for example, is of opinion, that there are fulphureous exhalations always afcending into the Air, where they ferment with the nitrous acid, and fometimes take fire.' Dr. Franklin endeavours to point out the manner it is effected, and why the Clouds are electrifed negatively. When a portion of Water,' he fays, 'is in its common denfe ftate, it can hold no more electrical fluid than it has; if any be added it spreads on the furface.

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229. When the fame portion of Water is rarefied into vapour, and forms a Cloud, it is then capable of receiving and absorbing a • much

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much greater quantity, there is room for each particle to have an electric Atmosphere.'

230. • Thus Water, in its rarefied state or in the form of a Cloud, will be in a negative • state of electricity; it will have less than its • natural quantity; that is, less than it is naturally capable of attracting and absorbing in that state.' See Mr. Franklin's Letters on

Electricity. p. 119.

231. A Cloud being by any means fupplied from the Earth, may ftrike into other Clouds that have not been fupplied, or not so • much fupplied; and those to others, till an equilibrium is produced among all the Clouds that are within ftriking distance of each other.' ibid. p. 120.

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232. Nor are we any longer at a lofs for the reafon of that which before fomewhat perplex'd the fubject, namely, by what means it is kindled up into fire, as we called it: Of this we are now very clearly informed from almoft all Experiments. — We cannot bring fo much as a Finger or iron Rod to the prime Conductor, when electrifed, without having an hint of the manner, how it is performed; but if it be collected in the glafs Receiver, much more is accumulated and is much longer retain'd, although much more condensed than on the prime Conductor, it being frequently retain'd there for many hours, fometimes for a whole day. At fome other times the accumulation is fo great and rises so high as to burst

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