Sun; and therefore the attractive Force of the Sun not only acts on the Bodies of the Planets, placed at given Distances, and very nearly in the fame Plane, but reaches alfo to the Comets in the moft different Parts of the Heavens, and at the most different Distances. This therefore is the Nature of gravitating Bodies, to propagate their Force at all Diftances, to all other gravitating Bodies. But from thence it follows, that all the Planets and Comers attract each other 'mutually, and gravitate mutually towards each other which is alfo confirmed by the Perturbation of Jupiter and Saturn, obferved by Aftronomers, which is caufed by the mutual Actions of thefe two Planets upon each other; as alfo from that very flow Motion of the Apfides, above taken Notice of, and which arifes from a like Caufe.

WE have now proceeded fo far as to fhew that it must be acknowledged, that the Sun, and the Earth, and all the Heavenly Bodies attending the Sun, attract each other mutually. Therefore all the leaft Particles of Matter in every one, must have their feveral attractive Forces, whofe effect is, as their Quantity of Matter; as was fhewn above of the terreftrial Particles. At different Distances, thefe Forces will be alfo in the Duplicate Ratio of the Diftances reciprocally; for it is Mathematically demonftrated, that Particles attracting according to this Law, will compofe Globes attracting according to the fame Law.

THE foregoing Conclufions are grounded on this Axiom which is received by all Philofophers; namely that effects of the fame kind, that is, whofe known Properties are the fame, take their rife from the fame Causes, and have the fame unknown Properties alfo. For who doubts, if Gravity be the Caufe of the Defcent of a Stone in Eu rope, but that it is alfo the Caufe of the fame Defcent in America? If there is a mutual Gravitation betwen a Stone and the Earth in Europe, who will deny the fame to be mutual in America? Ifin Europe, the attractive Force of a Stone and the Earth are compounded of the attractive Forces of the Parts; who will deny the like Compofition in America? If in Europe, the Attraction of the Earth be propagated to all kinds of Bodies, and to all Diftances; why may it not as well be propagated in like Manner in America? All Philofophy is founded on this Rule; for if that be taken away, we can affirm nothing of Univerfals. The Con

ftitution

ftitution of particular Things is known by Obfervations and Experiments; and when that is done, it is by this, Rule that we judge of the Nature of fuch Things in general..

SINCE then all Bodies, whether upon Earth, or in the Heavens, are heavy, fo far as we can make any Experiments or Obfervations concerning them; we must certainly allow, that Gravity is found in all Bodies univerfally. And in like Manner, as we ought not to fuppofe that any Bodies can be otherwise than extended, moveable, or impenetrable; fo we ought not to conceive, that any Bodies can be otherwife than heavy. The Extenfion, Mobility, and Impenetrability of Bodies, become known to us, only by Experiments; and in the very fame Manner, their Gravity becomes known to us. All Bodies we can make any Obfervations upon, are extended, moveable, and impenetrable; and thence we conclude all Bodies, and those we have no Obfervations concerning, to be extended, and moveable, and im-. penetrable. So all Bodies we can make Obfervations on, we find to be heavy; and thence we conclude all Bodies, and thofe we have no Obfervations of, to be heavy alfo. If any one fhould fay, that the Bodies of the fixed Stars are not heavy, because their Gravity is not yet observed; they may fay, for the fame Reason, that they are neither extended, nor moveable, nor impenetrable, because these Affections of the fixed Stars are not yet obferved. In fhort, either Gravity must have a Place among the Primary Qualities of all Bodies, or Extenfion, Mobility, and Impenetrability muft not. And if the Nature of Things is not rightly explained by the Gravity of Bodies, it will not be rightly explained by their Extenfion, Mobility, and Impenetrability.

SOME, I know, difapprove this Conclufion, and mutter fomething about occult Qualities. They continually are cavilling with us, that Gravity is an occult Property; and occult Caufes are to be quite banished from Philo fophy. But to this the Answer is eafy; that those are indeed occult Caufes, whofe Existence is occult; and imagined, but not proved; but not those whofe real Exiftence is clearly demonftrated by Obfervations. Therefore Gravity can by no Means be called an occult Cause of the Cæleftial Motions; because it is plain, from the Phenomena, that fuch a Virtue does really exift. Thofe rather have Recourfe to occult Caufes; who fet imagina

ry

ry Vortices of a Matter entirely fictitious, and imperceptible by our Senfes, to direct thofe Motions.

BUT fhall Gravity be therefore call'd an occult Caufe, and thrown out of Philofophy, because the Caufe of Gravity is occult, and not yet difcovered? Thofe, who affirm this, fhould be careful not to fall into an Abfurdity that may overturn the Foundations of all Philofophy. For Causes use to proceed in a continued Chain from thofe that are more compounded to thofe that are more fimple ; when we are arrived at the moft fimple Caufe, we can go no farther. Therefore no mechanical Account, or Explanation of the most fimple Caufe, is to be expected, or given; for if it could be given, the Caufe were not the moft fimple. Thefe moft fimple Caufes will you then call occult, and reject them? Then you must reject those that immediately depend upon them, and confequently thofe which depend upon thefe laft, till Philofophy is quite cleared and difencumbered of all Causes.

SOME there are, who fay that Gravity is præternatural, and call it a perpetual Miracle. Therefore they would have it rejected, becaufe præternatural Caufes have no Place in Phyfics. It is hardly worth while to spend Time in anfwering this ridiculous Objection, which overturns all Philofophy. For either they will deny Gravity to be in Bodies; which cannot be faid: Or elfe, they will therefore call it præternatural, because it is not produced by the other Affections of Bodies, and therefore not by mechanical Causes. But certainly there are primary Affections of Bodies; and thefe, because they are primary, have no Dependance on the others. Let them confider whether all these are not in like manner præternatural, and in like manner to be rejected ; and then what kind of Philofophy we are like to have.

SOME there are who diflike this celeftial Phyfics, because it contradicts the Opinion of Des-Carres, and feems Phardly to be reconcil'd with them. Let thefe enjoy their 2:own Opinion; but let them act fairly; and not deny the fame Liberty to us, which they demand for themfelves. Since then the Newtonian Philofophy appears true to us, let us have the Liberty to embrace and retain it, and to follow Caufes proved by Phenomena, rather than Caufes only imagined, and not yet proved. The Buliness of

true

true Philofophy, is to derive the Natures of Things from Caufes truly exiftent; and to enquire after thofe Laws on which the Great Creator actually chofe; to found this moft beautiful Frame of the World, not those on which he might have done the fame, had he fo pleased. It is reafonable enough to fuppofe, that from feveral Caufes, fomewhat differing from each other, the fame effect may tarife; but the true Caufe will be that, from which it truly and actually does arife; the others have no Place in true Philofophy. The fame Motion of the Hour-hand in a Clock, may be occafion'd either by a Weight hung, or a Spring fhut up within. But if a certain Clock fhould be really moved with a Weight; we should laugh at a Man that would fuppofe it moved by a Spring, and from that Principle, fuddenly taken up, without farther Examination, fhould go about to explain the Motion of the Index; for certainly the Way he ought to have taken, should have been actually to look into the inward Parts of the Machine, that - he might find the true Principle of the propofed Motion.

"

THE like Judgment ought to be made of thofe Philofophers, who will have the Heavens to be filled with a moft fubtile Matter, which is perpetually carried round in Vortices. For if they could explain the Phenomena ever fo accurately by their Hypothefes, we could not yet fay, that they have difcovered true Philofophy, and the true Caufes of the Celeftial Motions, unlefs they could either demonstrate that those Caufes do actually exist, or at least, that no others do exift. Therefore if it be made clear, that the Attraction of all Bodies is a Property actually exifting in rerum natura and if it be alfo fhewn how the Motions of the Celestial Bodies may be folved by that Property; it would be very impertinent for any one to object, that these Motions ought to be accounted for by Vortices; even though we fhould never so much allow fuch an Explication of thofe Motions to be poffible. But we allow no fuch Thing, for the Phenomena can by no means be accounted for by Vortices; as Sir Ifaac Newton, has abundantly proved from the clearest Reasons. So that Men must be ftrangely fond of Chimeras, who can fpend their Time folidly, as in patching uph ridiculous Figment, and fetting it off with new Comments of their own. To dout The Remainder of this bin our next. ]wa

Enigma's

Of an ENIG M A.

Æ

NIGMAS have been of very ancient ftanding, and the propofing of them, a Custom as old as the Times of SAMPSON, who, upon the Day of his Nuptials, gave one to the young Men his Companions, to find out. It was ufual alfo among Princes, to fend them to one another, with the Offer of a Reward to him who difcovered it, or to be mulated if he could not: An Enigma is an ingenious obfcuring of the plaineft Things; which, when discover'd, ftrikes the Soul with Surprize, while we pleafingly wonder to fee how it was poffible to lay as it were a Veil before the Sun. A perfect and compleat Enigma pleafes more when the Thing it means is known, than it did before; and is read again. as a Defcription thereof. In the Compofition of an Enigma, we may lawfully make ufe of Tropes and Metaphors, the better to conceal the Subject; but we ought not to put in any Thing paradoxical. As a Mafter Piece of this Kind, I fhall infert the two foliowing ones from the Gentleman's Magazine, and leave the Explication of them to the ingenious Reader.

T

ENIGMA the Firft.

HINK not, fair LADIES, I'm a Cheat,
Tho' I have never feen as yet

A HANDI could not 'counterfeit.

And though to Brutes my Birth I owe,
And fo my Pedigree's but low,

C

M

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