PHYSICS. that now runs under London-bridge, is not the fame that ran there an hour ago, and is quite other than that which will run there an hour hence. And, fo the flame of a candle, is faid to be the fame, for many hours together, tho' it, indeed, be every minute a new body; and tho' the kindled particles that compofe it, at any time affign'd, are continually putting off the form of flame, and are repair'd by a fucceffion of the like. Nor is it by the vulgar only, that the notion of identity has been hard to be obtain'd; for, it fees, that even the ancient philofophers have been puzzled about it; witnefs their difputes, whether the fhip of Thefeus were the fame, after it had been fo far repair'd, from time to time, to preserve it as a monument, that fcarce any plank remain'd of the former timber. And, even, in metaphyfics, I think it no eafy task, to establish a true and adequate notion of identity; and clearly to determine, what is the true principle of individuation. And, this is not furprizing; for, almost every man, who thinks, conceives in his mind, this, or that quality, relation or aggregate of qualities, to be that which is effential to a certain body, and proper to give it a peculiar denomination; whereby it comes to pafs, that, as one man chiefly refpects this thing, and another that, in a body that bears fuch a name; fo one may eafily look upon a body as the fame, because it retains what he chiefly confider'd in it; whilft another thinks it to be chang'd, because it has loft that which he thought was the denominating quality, or attribute. Thus philofophers, and phyficians difagree about water, and ice; fome taking the latter to be but the former difguiz'd; because they are both of them cold, and fimple bodies; and the latter eafily reducible to the former, by being freed from the exceffive adventitious degree of coldness; whilft others, looking upon fluidity, as effential to water, think ice, upon account of its folidity, to be a diftinct fpecies of body. And fo the Peripatetics, and chymifts often difagree about the afhes and Calces of burnt bodies; the first referring them to earth, because of their permanency, and fixednefs; and many chymifts taking them to be bodies fui generis, because common afhes ufually contain a cauftic falt; whereas earth ought to be infipid. And, the like may be faid of fome wood-ashes, and lime-ftone, and even coral; which when well calcin'd, and fresh, have a pungent taft: befides, fome of them, that are infipid, may be eafily reduced into metals, as the Calces of lead and copper. Thefe difficulties, about the notion of identity, being obferv'd, will render it less strange, that, among the ancient Hebrews and Greeks, whose languages were fo remote, in several refpects from ours, the familiar expreffions, employ'd about the sameness of a body, fhould not be fo precife, as those who maintain the refurrection, in the most rigid fenfe, would have them. In the next place, I obferve, we may, agreeably with feripture, fuppofe, that a comparatively fmall quantity of the matter of a body, being increas'd, either by affimilation, or other convenient appofition of parts, may bear the name of the former body; as a large crop of corn, arifing from a comparatively finall quantity of feed fown. And here it may be proper to mention an experiment, made by two ac PHYSICS. quaintance of mine, men of great veracity and judgment, who both affu red me, that having fown in a garden fome afhes of a plant like our EnLih red poppy, they, fooner than was expected, produced certain plants, larger and fairer than any of that kind which had been seen in those parts. Now this feems to argue, that in the faline and earthy, that is, the fix'd particles of a vegetable, that has been diffipated; and destroyed by the violence of the fire, there might remain a plaftic power, enabling them to contrive difpos'd matter fo, as to re-produce fuch a body as was formerly destroy'd. But to this plaftic power, refiding in any portion of the deftroy'd body itfelf, it will not perhaps be neceffary to have recourse in our prefent undertaking, fince an external and omnipotent agent can without it perform all that I need contend for.. Bion, To come then to a more clofe confideration of thofe difficulties which The first objeare faid to demonftrate the impoffibility of the refurrection. &tion against the refurre'Tis faid, when a man is once really dead, many parts of his body will, according to the course of nature, refolve themfelves into multitudes of fteams, that wander in the air; and the remaining parts, which are either liquid, or foft, undergo fo great a corruption and change, that 'tis not poffible fo many fcatter'd corpufcles fhould be again brought together, and re-united, after the fame manner wherein they exifted in a human body, whilft it was yet alive. And, they fay, much more impoffible is it to effect this re-union, if the body have been, as it often happens, devour'd by wild beafts, or fifh; fince, in this cafe, tho' the featter'd corpufcles of the carcass might be recover'd, as particles of matter; yet, having already pafs'd into the fubftance of other animals, they are quite tranfmuted by the new form of the beast or fish that devour'd them, and of which they now make a substantial part. Yet far more impoffible will this renewal be, if we put the cafe, that the body was devoured by Cannibals; for then the fame flesh, belonging fucceffively to two different perfons, 'tis impoffible that both should have it restor❜d to them at once, or that any footsteps fhould remain of the relation it had to the firft poffeffor. But, in anfwer to this grand objection, I have feveral things to Answer’d. offer. And, tt, A human body is not like a ftatue of brafs, or marble, that may continue, as to fenfe, whole ages, in a permanent ftate; but is in a perpetual flux, or changing condition; fince it grows, in all its parts, and all its dimenfions, from a corpufcle no bigger than an infect, to the full ftature of a man; which could not happen but by a conftant appofition, and affimilation of new parts, to the primitive ones, of the little embryo. And fince men, as other animals, grow but to a certain degree, and till a certain age, and therefore muft difcharge a great part of what they eat and drink by infenfible perfpiration, which Sanctorius's ftatical experiments and mine affure me to be fearce credibly great, as to men, and fome other animals, both hot and cold; it will follow, that in no very great compafs PHYSICS. of time, a large part of the substance of a human body, must be changed. Yet 'tis confiderable, that the bones are of a stable and lafting texture; as I found, not only by fome chymical trials, but by the skulls and other bones of men, whom history records to have been kill'd an exceeding long time ago. 2dly, There is no determinate bulk, or fize, neceffary to make a human body pafs for the fame; and a very small portion of matter, will fometimes, ferve the turn. Thus an embryo, for inftance, in the womb, a newborn child, a man at his full ftature, and a decrepit, aged perfon, notwithstanding the vaft difference of their fizes, are ftill reputed to be the fame perfon; as is evident by the custom of crowning kings and emperors in the mothers womb; and by putting malefactors to death in their old age, for crimes committed in their youth. And, if a very tall, and unwieldy fat man, fhould as it fometimes happens, be reduced by a confumption, almoft to a skeleton; yet none would deny that this wafted man, were the fame with him that had once fo vaft a body. : 3dly, A body may either confift of, or abound with fuch corpufcles, as may be variously affociated with thofe of other bodies, and exceedingly difguized by the mixtures, yet retain their own nature: and of this we have various inftances in metals. Thus gold, for example, when diffolv'd in Aqua regia, paffes for a liquor; and, when dextrously coagulated, appears a falt, or vitriol; by another alteration, I have made it part of the fewel of a flame; being dextrously conjoin'd to another mineral, it may be reduced to glass; well precipitated with mercury, it makes a glorious tranfparent powder; precipitated with spirit of urine, or oil of tartar per deliquium, it makes a fulminating calx, that goes off very eafily, yet is far stronger than gun-powder; precipitated with another certain alkali, the fire turns it to a fix'd and purple calx. But notwithstanding all these, and various other disguizes, the gold retains its nature, as may be prov'd by chymical operations, efpecially by reductions. And mercury, is of a more changeable nature than gold; fometimes putting on the form of a vapour; fometimes appearing in that of an almost infipid water; fometimes affuming the form of a red powder; fometimes that of a white, or yellow one; of a cryftalline falt, of a malleable metal; and of what not? Yet, all these are various dreffes of the fame quickfilver, which a skilful artift may eafily make it put off, and appear again in its native shape *. mentation, rarify into feveral forts of air; and this air by fermentation, and "fometimes without it, returns into dense "bodies. Mercury fometimes appears in And tho' it be true that inftances of the permanence of corpufcles under- PHYSICS. going fucceffive difguizes, may be much easier found among metals and minerals, than vegetables and animals; yet there are fome to be met with among thefe too: for, not to mention Hippocrates's affirmation, about purging a child with the milk of an animal, that had taken elaterium, I once, in Savoy, obferv'd all the butter, that was made in fome places, during the fpring feafon, tafted very much of a certain weed, which, at that time, abounds in the fields there. And confidering how many elaborate alterations the rank corpufcles of this weed must have undergone, in the various digeftions in the cow's ftomach, heart, udder, &c. and that afterwards two feparations, at leaft, were made, the one of the cream from the rest of the milk, and the other of the unctuous parts of the cream from the ferum; it will fcarce be deny'd, that vegetable corpufcles may, by affociation, pafs thro' various difguizes, without lofing their nature, especially fince the effential attributes of fuch corpufcles may remain undeftroy'd, tho' no fenfible quality furvive, to make proof of it, as is afforded by our example in the offenfive tafte. And befides what we commonly observe on the fea-coaft, of the fishy taste of those fea-birds that feed only upon fish; I purpofely inquired of an obferving man, who lived upon a part of the Iris coaft where the custom is to fat their hogs with a fort of shell-fish, wherewith that place very much abounds, about the taste of their pork; and he affured me, that the flesh had so strong and rank a favour of the fish, that strangers could not endure to eat it. There is a certain fruit in America, well known to our English planters, which many of them call the prickle-pear, whofe very red juice, being eaten with the pulp of the fruit, of which it is a part, paffes thro' the various ftrainers, and digeftions of the body, fo unalter'd, as to render the urine red enough to perfuade thofe, who are unacquainted with this property, that they make bloody urine; as I have been several times affured, by unfufpected eye-witneffes. But, more odd is that, related by a learned man, who spent feveral years upon the Dutch and English plantations, in the Charibbe iflands; when speaking of "the form of a fluid metal, and sometimes "in the form of a hard, brittle metal; "fometimes in the form of a corrofive, "pellucid falt, called fublimate; fome"times in the form of a taftlefs, pellu-.. "cid, volatile white earth, call'd Mer"curius dulcis; or in that of a red, opake, "volatile earth, call'd cinnabar; or in that of a red or white precipitate; or in that of a fluid falt: and diftillation "turns it into vapour; and being agitated in vacuo, it fhines like fire. And, after "all these changes, it returns into its first "form of mercury. Eggs grow from in fenfible magnitudes, and change into a"nimals; tadpoles into frogs; and worms VOL. II. "into flies. All birds, beafts, and fishes, 66 66 try tinctures, and falts; and, by putrefa"ction, return again into watry fubftances. "Water, ftanding a few days, in the open air, yields a tincture, which (like "that of malt) by ftanding longer, yields a fediment, and a fpirit; but, before pu"trefaction, is fit nourishment for animals "and vegetables. And, among such va"rious and strange tranfmutations, why may not nature change bodies into light, "and light into bodies?" Newton. Optic. P. 349, 350. PHYSICS. a fruit call'd Janipa, or Junipa, growing in feveral of those islands, he fays, that at the feafon when this fruit falls from the tree, the hogs, which feed on it, have both their flesh and fat of a violet colour, as experience witneffeth; which colour is the fame that the juice dyes. And the like happens to the flesh of parrots, and other birds, that feed upon it. Having thus fhewn that the particles of a body may retain their nature under various difguizes, I proceed to add, that they may be stripp'd of thofe difguizes, or, to speak without a metaphor, be extricated from those compofitions wherein they are difguized; and that fometimes, by fuch ways as those who are strangers to the nicer operations of nature, would never have thought on; nor will not, perhaps, judge probable, when propofed. Tho' vitrification be look'd upon by chymifts as the ultimate action of the fire, and the moft powerful way of making infeparable conjunctions of bodies; yet even out of glass of lead, for inftance, made of fand, and the afhes of a metal, (tho' the tranfmutation feems fo great, that the dark and flexible metal is turn'd into a very transparent and brittle mafs) we have recover'd opake and malleable lead. And tho' there be several ways befides precipitations, of divorcing fubftances, that feem strictly, if not infeparably, united; yet, by precipitation alone, if a man have the skill to chufe proper precipitants, feveral feparations may be easily and thoroughly made, that every one would not think of: for 'tis not neceffary that in all precipitations, as is obferv'd in most of the vulgar ones, the precipitant fhould indeed make a feparation of the diffolv'd body from the mass or bulk of that liquor, or other adjunct, whereto 'twas before united, and not be able to perform this, without affociating its own corpufcles with those of the body it fhould refcue, and fo making, in fome sense, a new and farther compofition. That fome bodies may precipitate others, without uniting themselves with them, is eafily prov'd by the experiment of refiners in feparating filver from copper; for the mixture being diffolv'd in Aqua fortis, if the solution be afterwards diluted, by adding fifteen or twenty times as much common water, and you put into this liquor a copper-plate, you fhall quickly fee the filver begin to adhere to the plate; not in the form of calx, as when gold is precipitated to make Aurum fulminans, or tin-glass, to make a fine white powder for a fucus; but in the form of a fhining metalline substance, that needs no farther reduction, to be employ'd as good filver. And, by a proper precipitant, I have also, in a trice, reduced a large quantity of well-difguized mercury, into running quick-filver. And, if one can well appropriate the precipitants to the bodies they are to recover, very flight, and unpromising agents, may perform great matters in a fhort time. If you let a piece of camphire lie a while upon oil of vitriol, fhaking them now and then, it will be fo corroded by the oil, as totally to difappear therein, without retaining fo much as its smell, or without any manifeft fign of there being camphire in that mixture; yet that a vegetable |