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not reducible to any of tliofe in tlie great world. — By virtue 

 of thefe powers he flicws, " that the fmall particles aft on 

 each other even at a diftance, and that many of the phe- 

 nomena of nature are the refult of this adtion. Senlible 

 bodies, as we have already obferved, aft on each other 

 feveral ways ; and as we thus perceive the tenor and courfe 

 of nature, it appears highly probable that there may be 

 other powers of the like kind, nature being- always nniform 

 ■and confillent with herfelf. — Thofe jult mentioned, reach- 

 ing to fenfible diftances, have been jreiierally obferved; 

 but there may be others, \vhich reach to fuc!i fmall dif- 

 tances as have hitherto efcaped obfervation ; and this, it !s 

 probable, may be the cafe with elcftricity, even without 

 being excited by friftion. 



He then proceeds to confirm the reality of thefe fuf- 

 picions from a great number of phenomena and experiments, 

 which plainly a'gue fuch powers and aftions between the 

 particles of bodies, e. g. of falts and water, oil of vitriol 

 and water, aqua fortis and iron, fpirit of vitriol and falt-'petre, 

 and many other chemical fi'.bftances. He alfo fliews that 

 thefe powers are unequally llrong between different bodies ; 

 e. g. ftronger between the particles of fait of tartar and 

 thofe of aq"via fortis, than thofe of fdver; and between aqua 

 fortis and lapis calaminaris, than iron ; between iron and 

 copper, than filvcr, or mercury, &c. So fpirit of vitriol 

 afts on water, but more on iron or copper, &c. The 

 other experiments which countenance the exiilence of fueh 

 principles of attraftion in the particles of matter are in- 

 numerable, many of which may be found enumerated under, 

 the articles Affinity, Acid, Matter, Menstruum, 

 Salt, &c. 



Thefe aftions, by virtue of which the particles of the bodies 

 above mentioned tend towards each other, are called by the 

 general indefinite name attraftion, which is equally applicable 

 to all aftions by which dillant bodies tend towardseachother, 

 whether by impulfe, or by any other more latent power ; 

 and hence we can account for an infinity of phenomena 

 which would be otherwife inexplicable from the principle 

 of gravity ; fuch as cohefion, diffolution, coagulation, 

 cryftallization, the afcent of fluids in capillary tubes, 

 animal fecretion, fluidity, fixity, fermentation, &c. ; which 

 fee under their proper names. 



"Thus" (adds our incr.mparable author) "will nature be 

 found conformable to herfelf, and very fimple, performing 

 all the great motions of the heavenly bodies by the attrac- 

 tion of gravity which intercedes thofe bodies, and ahr.oll; all 

 the fmall ones of their parts, by fome other attraftive 

 power difFufed through their particles. Without fuch prin- 

 ciples, there never would have been any motion in the 

 world ; and without the continuance thereof, motion v%oi;!d 

 foon perith, there being otherwife a great decreafe or dimi- 

 nution thereof which is only fupphed by thefe aftive princi- 

 ples." Optics, p. 373- 



For thefe reafons it is certainly unjufl to declare againft 

 a principle which furniflies fo , beautiful a view, for 

 no otiier reafon but becaufe we cannot conceive how one 

 body fliould aft on another at a dillance. It is certain 

 that philofophy allows of no action but what is by im- 

 mediate contaft or impulfion (for how can a body exert 

 any aftive power where it does not exiil ? to fuppofe this ef 

 any thing, even of the Supreme Being himfelf, would per- 

 haps imply a contradiftion) ; yet wc fee effefts without feeing 

 any fuch impulfe; and where there are effefts, we can eafily 

 infer there are caufes, whether we fee them or not. We 

 may confider fuch effefts, therefore, without entering into 

 the confideration of the caufes, as indeed it feems the bufinefs 

 of a pliilofopher to do; for to exclude a number of pheno- 

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mcna which we fee, would be to leave a great chafm in 

 the hiftory of nature: and to argue about thofe whieli we 

 do not fee, would be to !)uild caftles in the air. Hence it 

 follows, that the phenomena of attraftion are matter of 

 phyfical confideration, and as fuch entitled to a fliare in the 

 fy'iem of pliyfics; but; that the caufes of them will only be- 

 come fo when they ijecome fenfible, i. e. when they appear 

 to be the effcft of fome ether higher caufes (fo:- a caufc is 

 no otherwife feen than as itfelf is an cffeft, fo that the firft 

 caufe mull, from the nature of things, be invifible) ; we are, 

 therefore, at liberty to fuppofe the caufes of attraftion 

 what we pleafe, without any injury to the efl'efts. The il- 

 luitrious Newton himlelf feems, indeed, a little irrefolute as 

 to the caufes, inclining fometimes to attribute gravity to the 

 aftion of an immaterial caufe, Optics, p. 343, ?;c.; and fome- 

 times to that of a material one, Ibid. p. 325. 



In his philofophy, the refearch into caufi-s is the lad 

 thing, and never comes under confideration till the- laws and 

 phenomena of the ifiefts be fettled; it being to thefe phe- 

 nomena that the caufe is to be accommodated. The caufe 

 even of any of the grofleft and inoft fenfible aftions is not 

 adequately known ; how impulfe or percufTion itfelf, for in- 

 fiance, produces its cffeft, that is, how motion is communi- 

 cated by one body to another, confounds the deepeft philo- 

 fophers; yet is impulfe received not only into philofophy, but 

 into mathematics ; and accordingly the laws and phenomena 

 of its efiefts m;'.ke the greatell; part of common mechanics. 



The other fpecies of attraftion, therefore, in which no 

 impulfe is remarkable, when their phenomena are fuffieiently 

 afecrtained, have the fame title to be promoted from phvfieal 

 to mathematical confideration ; and this without any pre- 

 vious inquiry into their caufes, which our conceptions, 

 may not be proportioned to; let them be occult, as all 

 caufes ftriftly ipeakingare, fo that their effefts, which alone 

 immediately concern us, be but apparent. See Causi;. 



Onr illullrious countryman, therefore, far from adulterat- 

 ing philofophy with any thing foreign or metaphyfical, as 

 many have reproached him with doing, has the glory of 

 having thrown every thing of this kind out of his fyftem, 

 and of having opened a new fource of the moft fublime me- 

 chanics yet known; it is hence, therefore, that we muft 

 expeft to learn the manner of the changes, produftions, 

 generations, corruptions, &c. of natural things; with all that 

 fcene of wonders which is opened to us by the operations of 

 chemiiliy. 



The caufe of attraftion was long accounted for, by fuppof- 

 ing that there exifted a certain unknown fubftance which 

 impelled all bodies towards each other; an hypothcfis to 

 which philofophers Iiad recourfc, from an opinion which had 

 condantly been admitted as a firlt principle, " that no body 

 can aft where it is not;" as if it were more difficult to con- 

 ceive why a change is produced in a body by another v/hich 

 is placed at a greater diftance, than why it is produced by 

 one which is fituate at a fmall dillance ; it being not only 

 as impofiible to explain the phenomena of attraftion by im- 

 pulfion as it is to conceive how bodies (liould be urged 

 towards each other by the aftion of an external fuljftance, 

 a.s how they fiiould be urged towards each other by a power 

 inherent in themfelves. The faft is, that we can neither 

 comprehend the one nor the other; no'r can any rcafon be 

 afligned why the Creator might not as eafily beilow upon 

 matter the power of afting upon matter at a difliance, as 

 the power of being afted upon and changed by matter in 

 aftual contaft. 



But we have no reafon befides for fimpofing that bodies 

 are ever in any cafe aftually in contaft. For all bodies are 

 diminiflicd in bulk by coldj that is to fay, their particles 



are 



