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certain Plulofophy allows of no Adion but .what is by imme- diate Conrad and Impullion : (Tor how can a Body exert any aftive Power there, where it does not exilt? To fuppofe this of any thing, even the fupreme Being himfelf, would perhaps imply a Contradidion.) Yet we fee Effeds without feeing any fuch Im- piilfe; and where there areEffeds, we can ealily infer there are Caufes, whether we fee them or no. But a Man may confider fuch Effeds, without entering into the Confideration of the Caufes; as, indeed, it feems the Bulinefs of a Philofopher to do : For to exclude a Number of Phenomena which we do fee, will be to leave a great Chafm in the Hiftory of Nature; and to ar»ue a- about Adions which we do not fee, will be to build Ca- ftles in the Air.— It follows, therefore, that the Phenomena of Attralimi, are Matter of phylicai Confideration, and as fuch en- titled to a Share m a Sylfcm of Phyficks; but that the Caufe, thereof will only become fo when they become fenfible ■ i e. when they appear to be the Effeds of fome other higher Caufes, ((or a Caule is no othcrwifc fcen than as it felf is an Effect, fo that the firft Caufe mull from the Nature of things be invifible.J We are therefore at Liberty to fuppofe the Caufes of AttraBi- rnti what we pleafe, without any Injury to the Effeds.— The il- luflrious Author himfelf feems a little irrefolute as to the Caufe; inclining, iometimcs, to attribute Gravity to the Adion of an immaterial Caufe, Officii, p. 343. & c . And fometimes to that of a material one. lb. p. 32^.
In his Phibfophy, the Refearch inro Caufes is the laft thing; and never comes m turn till the Laws and Phenomena of the Effed be iettled; it being to thefe Phenomena that the Caufe is to be accommodated.— The Caufe even of any, the grofleft , and molt ienlible Adion i s not adequately known- How Im- pulfe or Percuffioo it felf works its Effect, i. e. how Motion is communicated by Body to Body, confounds the deepeft Philo- fopbcrs; yet is Impulie received not only into Philolbphy, but into (V lathemattcks; and accordingly the La>vs and Phenomena of Its Effects, make the grearcft Part of common Mechanicks. bee Percussion, and Communication of Motion.
The other Species of AttraBion, therefore, when their Phe- nomena are fufficiently afcerrain'd, have the fame Title to be promoted from phyiical to mathematical Conliderations; and this, without any previous Inquiry into their Caufes, which our Conceptions may not be proportionate to : Let their Caufes be occult, as all Caufes ever will be; fo as their Effeds, which a- lone immediately concern us, be but apparenr. See Cause.
Our noble Countryman, then, far from adulterating Philofo- phy with any thing Foreign, or Metaphylical; as many have re-
¥' f* blm ' has the Glor >' of °P enin g a «ew Source of fub- limer Mechanicks, which, duly cultivated, might be of infinitely more Extent than all the Mechanicks yet known : 'lis hence a- lone we mud exped to learn the manner of the Changes, Pro- oiidions, Generations, Corruptions, 6-c. of natural things; with all that Scene of Wonders opened to us by the Operations of Chymiftry. Fee Generation Corruption, Operation,
UIYMISTRY, &c.
Some of our own Countrymen have profecuted the Difcove- ry with laudable Zeal : Dr. Keil particularly, has endeavoured to deduce fome of the Laws of this new Adion, and applied them BJfolve divers of the more general Ph enomena of Bodies, asCo- nclion, Fluidity, Elafticity, Softnels, Fermentation, Coagulati- on, &c. And Dr. Friend feconding him, has made a further Application of the fame Principles, to account at once, for al- rcoll i,l the Phenomena that Chymiftry prefents.— So that the new Mechanicks fhould feem already ra'ifed to a compleat Sci- ence; and nothing can now turn up, but we have an immediate Solution ot, from the attraBhv Force.
But this feems a little too precipitate; a Principle fo fertile, would have been further explored; its particular Laws, Limits, &<■ more iaduftrioufly deteded and laid down, e're we had gone to Application.— JttraSim, in the grots, is fo complex a ™"8- mat it may fulve a thoufand different things alike : The "otion is but one Degree more fimple and precife, than Adion ' "«, and till more of its Properties are afcerrain'd, it were bet- ki to apply it ld s , an d ftudy it more.
As a Specimen of the extent of the Principle, and the manner or applying it, we (hall here fubjoin the principal Laws andCon- prnons thereof, as fettled by Sir lfaac Newton, Dr. Keil, Dr.
&c.
j (, r ' '■ Belides that attraBive Power whereby the Planets ana ojtnets are retain'd in their Orbits; there is another, by Mien the icvera! Particles whereof Bodies conlift, attraB, and '= nmtua ly attraBed by, each other; which Power decreafes ftaiTO a du P licace Ratio of the IncreafeV the Di-
cr™, h M T '; T ra we have Ami 1 obfav'd, is demonftrable from a few , r • 0t Phenomena.— We (hall here only mention a bv tV n a " aobviousones; as > the Spherical Figure, affirmed ciple Th r ° PS ° f Fluids; which can ml y ari& from fuch Prin- f,lvcr into """'"? "** incorporating of two Sperules of Quick- of t 0e j r s °T' Up ™ the firft touch ' or extremely near approach Bubble im'm?; T h ° rifing 0t Watcr U P the Sides of a Glafs Water, or ofM thi;rein) hi g her than tlle Leve ' of the othcr Spheriot? Q m ^, u? a s P here of lron > or the like. See
As to the jufl Law of this AttraBion, it is not yet determi- ned; only this we know in the general, that the force, in rece- ding from the Point of Contad, is dimiuilhed in a greater Pro- portion than that of the duplicate Ratio of the Diftances, which is the Law of Gravity. For that if the Diminution were only in fuch duplicate Ratio, the AttraBion at any fmall affignable Di- ftance would be nearly the fame as at the Point ot Contad: Whereas Experience reaches, that this AttraBion almoft vanifhes, and ceafes to have anyEffed, at the fmalleft affignable Diftance. —But whether to fix on a triplica e, quadruplicate, or fome other proportion to the increaling Diftances, is not afcertain'd by Ex- periment.
II. The Quantity of AttraBion in all Bodies, is exadly pro- portional to the Quantity of Matter in the attraBing Body; as being in reality the Relult or Sum of the united Forces of the AttraBions ot all thofe fingle Particles of which it is compos'd; or, in other Words, AttraBion in all Bodies is, ceteris paribus, as their Solidities.
Hence, i°. At equal Diftances the AttraBion! of homogene- al Spheres will be as their Magnitudes.— And,
2'. At any Diftance whatever, the AttraBion is as the Sphere divided by the Square of the Diftance.
This Law, it mull be noted, only holds in refped of Atoms, or the fmalleft conftituent Particles, fomerimes call'd Particle! of the laft Compoftion; and not of Corpufcles orCompofirions made up of rhefe; for they may be fo put together, as that the moil fohd Corpufcles may form the lighted Particles; i. e. the unfit- nefs of their Surfaces for intimate Contad, may occafion fuch great Interftic.es as will make their Bulks large in Proportion to their Matter.
III. If a Body confifl of Particles, every one whereof has an attradive Power decrealiug in a triplicate, or more than a tripli- cate Ratio of their Diftances; the Force wherewith a Particle is attraBedby that Body in the' Point of Contad, or at an infi- nitely little Diftance from the Contad, will be infinitely greater than if that Particle were placed at a given Diftance from the Body. See Infinite.
IV. Upon the fame Suppofition, if the attraBive Force at any affignable Diftance, have a finiteRatio ro its Gravity; this Force in the Point of Contad, or at an infinitely fmall Diftance, will be infinitely greater than its Power of Gravity.
_ V. But if in the Point of Contad the attraBive Force of Bo- dies have a finite Ratio to their Gravity; this Force in any affign- able Diftance is infinitely lefs than the Power of Gravity, and therefore ceafes.
VI. The attraBive Force of every Particle of Matter in the Point of Contad, almoft infinitely exceeds the Power of Gra- vity, but is not infinitely greater than that Power; and therefore in a given Diftance, the attraBive Force will vaniflr.
This attraBive Power, therefore, thus fuperadded to Matter, only extends to Spaces extreamly minute, and vanifhes in greater Diftances; whence, the Motion of the heavenly Bodies, which are at prodigious Diftance from each other, cannot at all be di- fturb'd by it, but will continually go on as if there were no fuch Power in Bodies.
Where this attraBing Power ceafes 5 there, according to Sir lfaac Newton, does a repelling Power commence; or rather, the attraBmg does thence forward become a repelling Power. See Repelling Tower
VII. Suppofing a Corpufcle to touch any Body, the Force whereby that Corpufcle is impell'd, that is, the Force with which it coheres to that Body, will be proportionable to the Quantity of Contad: For the Parts farther remov'd from the Point of Contad, contribute nothing towards its Cohefion.
Hence, according to the Difference in the Contad of Parti- cles, there will 1 be different Degrees of Cohefion: ButthePowers of Cohefion are greateft when the touching Surfaces are Planes ■ in which cafe, ceteris paribus, the Force by which one Corpufcle adheres to others, will be as the Parts ot the touching Surfaces.
Hence it apfeart viby tvjo ferfeBly folijb'd Marbles, joirfd toge- ther by their plane Surface!, cannot be forcdafmider, but by a Weight •which much exceed! that of thk incumbent Air.
Hence alfo may be drawn a Solution of that famous Problem concerning the Cohefion of the Farts of Matter. See Cohesion.
VIII. The Power of AttraBion in the fmall Particles iiicreafes, as the Bulk and Weight of the Particles diminifhes.
For, the Force only ading at or near the Point of Contad, the Momentum muft be as the Quantity of Contad, that is', as the Denfityof the Particles, and the Largenefs of their Surfaces: But the Surfaces of Bodies increafe or decreale as the Squares, and the Solidities as the Cubes of the Diameter. Confequenrly, the fmalleft Particles having the largeft Surfaces in proportion to their Solidities, are capable of more Contad, &c.
Thofe Corpufcles are moft ealiiy feparated from one another, whofe Contacts are the feweft and the lead, as in Spheres infi- nitely fmall.
Hence we have the Caufe of Fluidity. See Fluidity, Wa- ter, &c.
IX. The Force whereby any Corpufcle is drawn to another nearly adjacent Body, fuffers no Change in its Quantity, let the Matter of the attraBmg Body be increafed or diminifhed; fup-
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