briate, and to produce a calm and fteddy joy like the effect of good news, without that finking of fpirits which is a fubfequent effect of all fermented cordials. I may add, without all other inconvenience, except that it may, like any other medicine, be taken in too great a quantity for a nice ftomach. In which cafe it may be right, to leffen the dose, or to take it only once in the four and twenty hours, empty, going to bed (when it is found to be leaft offenfive) or even to fufpend the taking of it for a time, till nature fhall feem to crave it, and rejoice in it's benign and comfortable spirit. 218. Tar-war ferving as a vehicle to this fpirit is both diuretic and diaphoretic, but feems to work it's principal effect by affifting the vis vitæ, as an alterative and cordial, enabling nature by an acceffion of congenial fpirit, to affimilate that which could not be affimulated by her proper force, and fo to fubdue the fomes morbi. And this fhould f:em in moft cafes the beft and fafeft courfe. Great evacuations weaken nature as well as the disease. And it is to be feared that they who use falivations and copious bleedings may, though they fhould recover of the diftemper, in their whole life be never able to recover of the remedies. 219. It is true indeed, that in chronical cafes there is need of time to compleat a cure, and yet I have known this tar-water in diforders of the lungs and ftomach to prove a very speedy remedy, and to allay the anxiety and heat of a fever in an inftant, giving eafe and fpirits to the patient. This I have often experienced, not without furprife, at feeing these falutary effects follow fo immediately in a fever on taking a glass of tar-water. Such is the force of thefe active vivifying principles contained in this balfam. 220. Force 220. Force or power, ftrickly speaking, is in the agent alone who imparts an equivocal force to the invifible elementary fire, or animal spirit (a) of the world, and this to the ignited body or visible flame, which produceth the fense of light and heat. In this chain the first and last links are allowed to be incorporeal: the two intermediate are corporeal, being capable of motion, rarefaction, gravity, and other qualities of bodies. It is fit to distinguish these things, in order to avoid ambiguity concerning the nature of fire. 221. Sir Ifaac Newton in his Optics, afks; Is not fire a body heated fo hot as to emit light copiously for what elfe, adds he, is a red hot iron than fire? Now it should seem, that to define fire by heat, would be to explain a thing by it felf. A body heated fo hot as to emit light is an ignited body, that is, hath fire in it, is penetrated and agitated by fire, but is not itself fire. And although it fhould in the third foregoing acceptation, or vulgar fenfe pafs for fire, yet it is not the pure elementary (b) fire in the fecond or philofophic fenfe, fuch as was understood by the fages of antiquity, and fuch as is collected in the focus of a burning glass; much lefs is it the vis, force, or power of burning, deftroying, calcining, melting, vitrifying, and raifing the perceptions of light and heat. This is truly and really in the incorporeal agent, and not in the vital spirit of the universe. Motion, and even power in an equivocal fenfe, may be found in this pure æthereal fpirit, which ignites bodies, but is not itself the ignited body, being an inftrument or medium (c) by which the real agent doth operate on groffer bodies. (a) 153, 156, 157. (b) 190. (c) 160. 222. It 222. It hath been fhewed in Sir Ifaac Newton's Optics, that light is not reflected by impinging on bodies, but by fome other caufe. And to him it feems probable, that as many rays as impinge on the folid parts of bodies, are not reflected but ftifled and retained in the bodies. And it is cer tain, the great porofity of all known bodies affords room for much of this light or fire to be lodged therein. Gold itself, the most folid of all metals, feems to have far more pores than folid parts, from water being preffed through it in the Florentine experiment, from magnetic effluvia paffing, and from mercury entering its pores fo freely. And it is admitted that water, though impoffible to be compreffed, hath at least forty times more pores than folid parts. And as acid particles, joined with thofe of earth in certain proportions, are fo closely united with them, as to be quite hid and loft to all appearance, as in mercurius dulcis and common fulphur, fo alfo may we conceive the particles of light or fire to be absorbed and latent in groffer bodies. 223. It is the opinion of Sir Ifaac Newton, that fomewhat unknown remains in vacuo, when the air is exhaufted. This unknown medium he calls æther. He fuppofeth it to be more fubtil in its nature, and more swift in its motion, than light, freely to pervade all bodies, and by its immenfe elafticity to be expanded throughout all the hea vens. Its denfity is fuppofed greater in free and open spaces, than within the pores of compact bodies. And, in paffing from the celestial bodies to great distances, it is fuppofed to grow denfer and denfer continually; and thereby cause those great bodies to gravitate towards one another, and their refpective parts towards their centers, every body body endeavouring to pass from the denser parts of the medium towards the rarer. 224. The extreme minutenefs of the parts of this medium and the velocity of their motion, together with its gravity, denfity, and elaftic force, are thought to qualify it for being the caufe of all the natural motions in the univerfe. To this cause are afcribed the gravity and cohesion of bodies. The refraction of light is alfo thought to proceed from the different denfity and elaftic force of this ætherial medium in different places. The vibrations of this medium alternately concurring with, or obftructing the motions of the rays of light, are fuppofed to produce the fits of eafy reflexion and tranfmiffion. Light by the vibrations of this medium is thought to communicate heat to bodies. Animal motion and fenfation are also accounted for by the vibrating motions of this ætherial medium, propagated thro' the folid capillaments of the nerves. În a word, all the phænomena and properties of bodies, that were before attributed to attraction, upon later thoughts feem afcribed to this æther, together with the various attractions themselves. 225. But in the philofophy of Sir Ifaac Newton, the fits (as they are called) of eafy transmission and reflexion, seem as well accounted for by vibrations excited in bodies by the rays of light, and the refraction of light by the attraction of bodies. To explain the vibrations of light by those of a more subtil medium, feems an uncouth explication. And gravity feems not an effect of the denfity and elafticity of æther, but rather to be produced by fome other caufe; which Sir Ifaac himself infinuates to have been the opinion even of those ancients who took vacuum, atoms, and the gravity of atoms for the principles of their philofophy, tacitly attri buting buting (as he well obferves) gravity to fome other caufe diftinct from matter, from atoms, and confequently, from that homogeneous æther or elaftic fluid. The elafticity of which fluid is fup pofed to depend upon, to be defined and measured by it's denfity; and this by the quantity of matter in one particle, multiplied by the number of particles contained in a given space; and the quan tity of matter in any one particle or body of a given fize to be determined by it's gravity. Should not therefore gravity feem the original property and first fuppofed? On the other hand, if force be confidered as prefcinded from gravity and mat ter, and as existing only in points or centers, what can this amount to but an abstract spiritual incorporeal force? 226. It doth not feem neceffary from the pha nomena, to fuppofe any medium more active and fubtil than light or fire. Light being allowed to move at the rate of about ten millions of miles in a minute, what occafion is there to conceive ano→ ther medium of ftill fmaller and more moveable parts. Light or fire feems the fame with æther. So the ancients understood, and fo the Greek word implies. It pervades all things (a), is every where prefent. And this fame fubtil medium ac cording to it's various quantities, motions, and determinations, fheweth itfelf in different effects or appearances, and is æther, light, or fire. 227. The particles of æther fly afunder with the greatest force, therefore when united they muft (according to the Newtonian doctrine) attract each other with the greatest force; therefore they are acids (b), or conftitute the acid; buɛ this united with earthy parts maketh alkali, as Sir Ifaac teacheth in his tract De acido; alkali, as ap (a) 157... (6) 130. pears |