are moved towards the particles of falt, and joined with them. And when we behold vulgar falt not to flow per deliquium, may we not conclude that the fame law of nature and motion doth not obtain between it's particles and thofe of the floating vapours? A drop of water affumes a round figure, because it's parts are moved towards each other. But the particles of oil and vinegar have no fuch difpofition to unite. And when flies walk in water without wetting their feet, it is attributed to a repelling force or faculty in the fly's feet. But this is obfcure, though the phænomenon be plain.

236. It is not improbable, and feems not unfupported by experiments, that, as in algebra, where pofitive quantities ceafe there negative begin, even so in mechanics, where attracting forces cease there repelling forces begin; or (to exprefs it more properly) where bodies cease to be moved towards, they begin to be moved from each other. This Sir Ifaac Newton infers from the production of air and vapours, whofe particles fly asunder with fuch vehement force. We behold iron move towards the loadstone, ftraws towards amber, heavy bodies towards the earth. The laws of thefe motions are various. And when it is faid, that all the motions and changes in the great world arife from attraction; the elafticity of the air, the motion of water, the defcent of heavy, and the afcent of light bodies, being all afcribed to the fame principle; when from infenfible attractions of moft minute particles at the smallest diftance, are derived cohesion, diffolution, coagulation, animal fecretion, fermentation, and all chemical operations; and when it is faid, that without fuch principles there never would have been any motion in the world, and without

the

the continuance thereof all motion would ceafe. In all this we know or understand no more, than that bodies are moved according to a certain order, and that they do not move themselves.

237. So likewife, how to explain all those various motions and effects, by the denfity and elafticity of æther, feems incomprehenfible (a). For inftance, why should the acid particles draw thofe of water and repel each other? why fhould fome falts attract vapours in the air, and others not? why should the particles of common falt repell each other, fo as not to fubfide in water? why should the most repellent particles be the most attractive upon contact? Or why should the repellent begin where the attractive faculty leaves off. Thefe, and numberless other effects feem inexplicable on mechanical principles, or otherwife than by recourse to a mind or spiritual agent (b). Nor will it fuffice from prefent phænomena and effects, through a chain of natural caufes, and fubordinate blind agents, to trace a divine intellect as the remote original cause, that first created the world, and then fet it a going. We cannot make even one fingle ftep in accounting for the phænomena, without admitting the immedi ate prefence and immediate action of an incorporeal agent, who connects, moves, and difpofes all things, according to fuch rules, and for fuch purposes as feem good to him.

238. It is an old opinion adopted by the moderns, that the elements and other natural bodies are changed each into other (c). Now, as the particles of different bodies are agitated by different forces, attracting and repelling, or, to fpeak more accurately, are moved by different laws, how can these forces (a) 153, 162. (b) 154, 220. (c) 148.

ᎾᎥᎢ

or laws be changed, and this change accounted for by an claftic æther? Such a medium, distinct from light or fire, feemeth not to be made out by any proof, nor to be of any use in explaining the phænomena. But if there be any medium employed, as a fubordinate caufe or inftrument in attraction, it would rather feem to be light (k); fince by an experiment of Mr. Boyle's, amber, that thewed no fign of attraction in the fhade, being placed where the fun-beams fhone upon it, immediately attracted light bodies. Befides, it hath been difcovered by fir Ifaac Newton, and an admirable discovery it was, that light is an heterogeneous medium (1) confifting of particles endued with original distinct properties. And And upon these, if I may venture to give my conjectures, it feemeth probable the specific properties of bodies, and the force of fpecific medicines may depend. Different fides of the fame ray fhall, one approach and the other recede from the Islandic cryftal; can this be accounted for by the elafticity of a fine medium, or by the general laws of motion, or by any mechanical principles whatever? And if not, what fhould hinder but there may be specific medicines, whofe operation depends not upon mechanical principles, how much foever that notion hath been exploded of late years?

239. Why may we not fuppofe certain idiofyncrafies, fympathies, oppofitions, in the folids or fluids or animal spirit of a human body, with regard to the fine infenfible parts of minerals or ve getables, impregnated by rays of light of different properties, not depending on the different fize, figure, number, folidity or weight of thofe particles,

(4) 152, 156.

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(7) 40, 181.

nor

nor on the general laws of motion, nor on the denfity or elafticity of a medium, but merely and altogether on the good pleafure of the Creator, in the original formation of things? From whence divers unaccountable and unforeseen motions may arife in the animal economy; from whence alfo various peculiar and fpecific virtues may be conceived to arife, refiding in certain medicines, and not to be explained by mechanical principles. For although the general known laws of motion are to be deemed mechanical, yet peculiar motions of the infenfible parts, and peculiar properties depending thereon, are occult and fpecific.

240. The words attraction and repulfion may, in compliance with cuftom, be used where, accurately fpeaking, motion alone is meant. And in that fenfe it may be faid, that peculiar attractions or repulfions in the parts, are attended with fpecific properties in the wholes. The particles of light are vehemently moved to or from, retained or rejected by objects. Which is the fame thing as to fay with Sir Ifaac Newton, that the particles of acids are endued with great attractive force (m), wherein their activity confifts; whence fermentation and diffolution; and that the moft repellent are, upon contact, the most attracting particles.

241. Gravity and fermentation are received for two moft extenfive principles. From fermentation are derived the motion and warmth of the heart and blood in animals, fubterraneous heat, fires, and earthquakes, meteors and changes in the atmosphere. And, that attracting and repelling forces operate in the nutrition and diffolution of animal and vegetable bodies, is the doctrine both of Hip

(m) 202.

pocrates

pocrates and Sir Ifaac Newton. The former of thefe celebrated authors, in his treatise concerning diet or regimen, obferves, that in the nourishment of man, one part repells and another attracts. And again, in the fame treatife, two carpenters, faith he, faw a piece of timber; one draws, the other pushes; these two actions tend to one and the fame end, though in a contrary direction, one up, the other down: This imitates the nature of man: πνεῦμα τὸ μὲν ἕλκει, τὸ δὲ ὠθέει.

242. It is the general maxim of Hippocrates, that the manner wherein nature acts confifteth in attracting what is meet and good, and in repelling what is difagreeable or hurtful. He makes the whole of the animal ceconomy to be adminiftred by the faculties or powers of nature. Nature alone,

faith he, fufficeth for all things to animals. She knows of herself what is neceffary for them. Whence it is plain, he means a confcious intelligent nature, that prefides and moves the ætherial fpirit. And tho' he declares all things are accomplished on man by neceffity, yet it is not a blind fate or chain of mere corporeal causes, but a divine neceffity, as he himself exprefly calls it. And what is this but an over-ruling intelligent power that difpofeth of all things?

243. Attraction cannot produce, and in that sense account for the phænomena, being it felf one of the phænomena produced and to be accounted for (n). Attraction is performed by different laws, and cannot therefore in all cafes be the effect of the elasticity of one uniform medium. The phænomena of electrical bodies, the laws and variations of magnetifm, and, not to mention other kinds, even

(#) 160, 235.

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