tendency of light bodies towards the rubb'd Tube, though the Tube was replete with Airs He therefore concluded that the action of the common Air muft neceffarily contribute to the Phænomenon : He alfo obferved, that if the Air was exhausted out of the glass Tube, and then rubb'd in the open air, it produced no fuch Effects among light bodies*

186. Prop. 5. p. 244. As the internal Air is neceffary to the action of the Effluvia, fo is ⚫the external too: Because, though the Tube was very full of Air, yet if rubb'd in vacuo, the attractive Power was quite loft.

187. Prop. 6. As therefore the internal Air feems neceffary, either to affift the electric Mat•ter in its Motion outwards, or at least to prevent its retiring inwards; fo the external Air appears to be as necessary to carry the light bo⚫dies (which we say are attracted †) towards • the Tube.

188. For if by the heat and rarefaction confequent upon the attrition, the Medium contiguous to the Tube, be made Specifically lighter; then of courfe, to keep up the balance, • the remoter Air, which is denfer, must press • in towards the Tube, and fo carry away (in * the Torrent) the little bodies lying in its

The Effects were then within fide of the Tube. + Notwithstanding Mr. Haukefbee confeffes the Phænomenon appears to be performed by Pulfion, yet we fee, he cannot forbear calling it Attractions

way

way thither alfo.' Thus Mr. Haukefbee feems naturally conducted to the fame conclufion, or nearly, as if he had had then in view the fame Rarity and Elafticity of the electrical Fluid, which we have fince found in it.

189. Thus we see when prefs'd with the difficulties attending electric Attraction, how - natural it is to have recourfe to an oppofite Principle, viz. that of Impulfe.

190. From all which it must seem reafonable, as well as agreeable with Experiment, to fuppofe that the limits furrounding the electri fed gilded Globell, the rubb'd Tube, &c. appear from the Effects to be fo extremely rare, as that light Bodies near thofe limits are impell'd as forcibly into them by the newly discover'd Pneuma or Spirit of Æther, as into a Torricellian Vacuum were it poffible to form one in the open Air, where it inftantly acquiring a Capfula or Cafe of the rare elaftic matter is as instantly repell'd out again. On this reasonable Poftulatum therefore (if it may not rather be term'd an Axiom) depends the principal Part of the whole electrical Phænomenon, and by it the most abstruse Parts (which otherwife appear fo much like inexplicable Paradoxes in thofe fuppofed alternate Attractions and Repulfions,) will be render'd intelligible, and the Experiments no longer feem irreconcileable with each other, as has been reprefented, but rather as the natural agreement and neceffary effects of their proper Causes.

# See Sect. 178.

CHAP.

!

CHA P. VIII.

PART 1.

SECTION 191.

Of the SOURCE from whence this Subtile
Matter is obtain'd in the Experiments.

A

CCORDING to my 2d. fundamental Principle, its Existence is unifal i. e. in all Space; not only in all open Spaces, but in all minute ones, even in the fmalleft Vacuities or Pores of the most folid and compacted Bodies And, notwithstanding it long eluded every Senfe; yet it doth really exift and is actually prefent in every thing we either handle or fee: And the Reason it escaped our Senfes fo long was from its very Nature, that is, it was not only invifible but so subtile and volatile as always to evade a strict Scrutiny: For otherwife Sir Ifaac, who fought most diligently after it, must have difcover'd it more minutely..

192. If then every grofs Body is replete with it, the largest Bodies must contain the greatest quantity, and confequently the Body of the Earth the most of all, which feems to be the Fountain from whence it is obtain❜d and to which it perpetually tends; and this will evidently appear to be the Cafe from the following Experiments.

193. Mr. Haukefbee was of opinion, that the electric matter was emitted from the internal fubftance of the Glafs on which the Attrition was made. See his Phyfico-mechan. Exp.

194. This was alfo the opinion of many others after him; and foon after the prefent Improvements commenced, many fuppofed it to be obtained from the Air; but on examination it appeared otherwife: For moft Experiments made by way of Trial on that fuppofition, when but a little varied, were found to clash with, and contradict each other.

195. On farther examination it plainly appear'd from a train of Experiments to be emitted from the pores of the Inftrument of Friction at the rubb'd glafs, and fupplied from the Earth thro' contiguous Bodies; and then the Experiments, as fo many clear evidences, were always confiftent with each other, tho' ever fo much varied; and tho chang'd into many different forms or fhapes, no contradiction or clafhing then happen'd. Experiments which prove

it are fuch as follow:

196. First. If the Fire be emitted from the pores of the Inftrument of Friction and fupplied from the Earth; then, confequently, if a Perfon's Hand be the Inftrument, the fire muft be flowing through his Body all the time, viz. from his feet to the palm of his hand. This is verified to fenfe, if the Room be darken'd; for between fuch parts of the palm as are nearly in contact with the revolving glafs Globe, it 0 2 ap

appears like exceeding fine threads of fire iffuing from numberless pores. Are not these fupplied by the contiguous particles, and those by the next, quite thro' the Body? But to prove that it enters at the fame time into his feet from the floor, let him step on a cake of Refin*, which will intercept the communication with the floor, and after that if he put but his Toe very lightly to the floor, the fire appears plainly between them, especially if the shoe he off And still more plainly, if a finger of a Perfon on the floor be brought to the foot, for then it will be not only visible but may be plainly felt and heard to fnap or explode.

197. Secondly. If the Perfon rubbing the Glafs only stands on folded woollen, instead of refin, it is fufficient; for then likewise it may be

The method commonly made ufe of to prove the electrical Fluid to be deriv'd from the Earth, was by mounting the whole Machine on original Electrics. But all that formality may be fpared, for if the Inftrument of Friction only be thus fupported, it is fufficient. This may be done by taking off the Cufhion that rubs the glafs Globe, and if inftead thereof, a Perfon fteps on a Cake of Refin, or a glass Stand, and applies the palm of his Hand to the revolving Globe, the leaft reflection will be fufficient to inform us, that the fame end must be anfwer'd in every refpect, fince the middle Zone of the Globe, from whence all the other parts the Apparatus are fupplied, can be no way fuppli ed it felf but from the Inftrument of friction.

feen

of