142. Air may alfo be faid to be the feminary of minerals and metals, as it is of vegetables. Mr. Boyle informs us, that the exhausted ores of tin and iron being expofed to the air become again impregnated with metal, and that ore of alum having loft its falt recovers it after the fame manner. And numberless inftances there are of falts produced by the air, that vaft collection or treafury of active principles, from which all fublunary bodies feem to derive their forms, and on which animals depend for their life and breath.

143. That there is fome latent vivifying spirit difperfed throughout the air, common experience fheweth; inafmuch as it is neceffary both to vege tables and animals (b) whether terreftrial or aquatic, neither beafts, infects, birds, nor fishes being able to fubfift without air. Nor doth all air fuffice, there being fome quality or ingredient, of which when air is deprived, it becometh unfit to main> tain either life or flame. And this even though the air fhould retain its elafticity; which, by the bye, is an argument that air doth not act only as an an tagonist to the intercoftal muscles. It hath both that and many other ufes. It gives and preferves a proper tone to the veffels: this elaftic fluid pro→ motes all fecretions: its ofcillations keep every part in motion: it pervades and actuates the whole ani mal fyftem, producing great variety of effects, and even oppofite in different parts, cooling at the fame time and heating, diftending and contracting, coagulating and refolving, giving and taking, fuftaining life and impairing it, preffing without and expanding within, abrading fome parts, at the fame time infinuating and fupplying others, producing various vibrations in the fibres, and fer

(b) 138, 139.

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ments

ments in the fluids; all which muft needs enfue from fuch a fubtile, active, heterogeneous and elaftic fluid.

144. But there is, as we have obferved, fome one quality or ingredient in the air, on which life more immediately and principally depends. What that is, though men are not agreed, yet it is agreed that it must be the fame thing that fupports the vital and the common flame; it being found that when air, by often breathing in it, is become unfit for the one, it will no longer ferve for the other. The like is obferveable in poifonous damps or fteams, wherein flame cannot be kindled. As is evident in the Grotto del cane near Naples. And here it occurs, to recommend the plunging them into cold water, as an experiment to be tried on perfons affected by breathing a poisonous vapour in old yaults, mines, deep holes or cavities under ground. Which, I am apt to think, might fave the lives of feveral, by what I have feen practifed on a dog convulfed, and in all appearance dead, but instantly reviving on being taken out of the abovementioned grotto and thrown into a lake adjacent.

145. Air, the general menftruum and feminary, feemeth to be only an aggregate of the volatile parts of all natural beings, which variously combined and agitated produce many various effects. Small particles in a near and close fituation strongly act upon each other, attracting, repelling, vibrating, Hence divers fermentations, and all the variety of meteors, tempefts, and concuffions both of earth and firmament. Nor is the microcofm lefs affected thereby. Being pent up in the viscera, veffels, and membranes of the body, by its falts, fulphurs, and elaftic power, it engenders colics, fpafms, byfteric disorders, and other maladies.

16. The specific quality of air is taken to be permanent

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permanent elasticity. Mr. Boyle is exprefsly of this opinion. And yet, whether there be any fuch thing as permanently elaftic air may be doubted, there being many things which feem to rob the air of this quality, or at leaft leffen and fufpend its exertion. The falts and fulphurs, for inftance, that float in the air abate much of its elafticity by their attraction.

147. Upon the whole it is manifeft, that air is no diftinct element, but a mass or mixture of things the most heterogeneous and even oppofite to each other (m), which become air, by acquiring an elafticity and volatility from the attraction of fome active, fubtile fubftance; whether it be called fire, æther, light, or the vital fpirit of the world; in like manner as the particles of antimony, of themfelves not volatile, are carried off in fublimation and rendered volatile, by cohering with the particles of fal ammoniac. But action and reaction being equal, the fpring of this æthereal fpirit is diminished by being imparted. Its velocity and fubtilty are alfo lefs from its being mixed with groffer particles. Hence found moves flower than light, as mud than water.

148. Whether air be only freed and fixed, or generated and deftroyed, it is certain that air begins and ceases to exert and fhew itself. Much by experiments feems to be generated, not only from animals, fruits, and vegetables, but also from hard bodies. And it is obferved by Sir Ifaac Newton, that air produced from hard bodies is most elaftic. The tranfmutation of elements, each into other, hath been anciently held. In Plutarch we find it was the opinion of Heraclitus, that the death of fire was a birth to air, and the death of air a birth to water. This opinion is alfo maintained by (2) 137, 145.

Sir

Sir Ifaac Newton. Though it may be queftioned, whether what is thought a change be not only a disguise.

149. Fire feems the most elastic and expanfive of all bodies. It communicates this quality to moift vapours and dry exhalations, when it heats and agitates their parts, cohering closely with them, overcoming their former mutual attraction, and caufing them, inftead thereof, reciprocally to repel each other and fly afunder, with a force proportionable to that wherewith they had cohered.

150. Therefore in air we may conceive two parts, the one more grofs, which was raised and carried off from the bodies of this terraqueous mafs: the other a fine fubtile spirit by means whereof the former is rendered volatile and elastic. Together they compofe a medium, whose elasticity is lefs than that of pure æther, fire, or fpirit, in proportion to the quantity of falts, vapours, and heterogeneous particles contained therein. Hence it follows, that there is no fuch thing as a pure fimple element of air. It follows alfo, that on the higheft mountains air fhould be more rare than in proportion to the vulgar rule, of the spaces being reciprocally as the preffures: and fo in fact it is faid to have been found, by the gentlemen of the French Academy of Sciences.

151. Æther, fire, or fpirit being attracted and clogged by heterogeneous particles becometh lefs active; and the particles cohering with thofe of æther, become more active than before. Air therefore is a mass of various particles, abraded and fublimated from wet and dry bodies of all forts, co-. hering with particles of æther; the whole permeated by pure æther, or light, or fire: for thefe words are used promifcuously by ancient philofophers.

152. This

152. This æther or pure invifible fire, the moft fubtile and elaftic of all bodies, feems to pervade and expand itself throughout the whole univerfe. If air be the immediate agent or inftrument in natural things, it is the pure invifible fire that is the first natural mover or fpring, from whence the air derives its power (a). This mighty agent is every where at hand, ready to break forth into action, if not reftrained and governed with the greatest wisdom. Being always reftless and in motion, it actuates and enlivens the whole vifible mafs, is equally fitted to produce and to destroy, diftinguishes the various stages of nature, and keeps up the perpetual round of generations and corruptions, pregnant with forms which it conftantly fends forth and reforbs. So quick in its motions, fo fubtile and penetrating in its nature, fo extenfive in its effects, it feemeth no other than the vegetative foul or vital spirit of the world.

153. The animal fpirit in man is the inftrumental or phyfical caufe both of fenfe and motion. To fuppofe fenfe in the world, would be grofs and unwarranted. But loco-motive faculties are evident in all its parts. The Pythagoreans, Platonists, and Stoics held the world to be an animal. Though fome of them have chofen to confider it as a vegetable. However the phænomena and effects do plainly fhew there is a fpirit that moves, and a mind or providence that prefides. This providence, Plutarch faith, was thought to be in regard to the world, what the foul is in regard to man.

154. The order and course of things, and the experiments we daily make, fhew there is a mind that governs and actuates this mundane fyftem, (a) 139, 149, 151.

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