STATICS.

Now whence can this increase of abfolute weight, obferv'd in the metals expofed to the mere flame, be deduced, but from fome ponderous parts Corollaries from of the flame? And how could these parts invade thofe of the metal inclofed in a glafs, otherwife than by paffing thro' the pores of that glass ?

this discovery.

That flame may

act as a men

make coalitions

it works on.

But I do not, by thefe experiments, pretend to make out the porofity of glafs, any farther than with regard to fome of the ponderable parts of flame; for, otherwise, glass is not easily penetrable.

Upon the whole, it appears, 1ft, That flame may be a menftruum, and ftruum, and work on fome bodies, not only by making a notable comminution, and difwith the bodies fipation of their parts, but, alfo, by a coalition of its own particles with thofe of the fretted body; and thereby, permanently, add fubftance and weight thereto. Nor is it repugnant to flame's being a menftruum, that, in our experiment, the lead and tin expofed to it, were but reduced to powder, and not diffolved in the form of a liquor, and kept in that ftate. For, befides that the interpofed glafs hinder'd the igneous particles from getting thro' in plenty enough, 'tis not neceffary that all menftrua fhould be fuch folvents. For whether it be, that the menftrua we think fimple, may be compounded of very different parts, whereof one may precipitate what is diffolved by the other, or for fome other caufe; it is certain, that fonie menftrua corrode metals, and other bodies, without keeping any confiderable part diffolved; as may be feen, if you put tin to a certain quantity of Aqua fortis, which will, in a very fhort time, reduce it, almoft totally, to a very white fubftance, that, when dry, is a kind of calx. And fo, with a due proportion of oil of vitriol, abftracted from quick-filver, by a ftrong fire, we have feveral times reduced the main body of the mercury into a white powder, whereof but an inconfiderable part was diffoluble in water. And fuch a white calx I have had, by the action of another fretting liquor on a body not metalline. But whether, as it feems probable, it be from the vehement agitation of the permeating particles of flame, that violently tear afunder the metalline corpufcles; or, from the nature of the igneous menftruum, which being, as 'twere, ftrain'd thro' glass itself, must be ftrangely minute; 'tis worth obferving how small a proportion, in point of weight, of the additional adhering body, may ferve to corrode a metal, in comparifon of the quantity of vulgar menftrua requifite for that purpofe. For, tho' we are obliged to employ, to make the folution of crude lead, feveral times its weight of fpirit of vinegar, or a large proportion of Aqua fortis; 'twas obferved in our experiment, that tho' the lead was increafed but fix grains in weight, yet above a hundred and twenty of it were fretted into powder; fo that the corrofive body appear'd to be but about the twentieth part of the corroded.

them.

That calces of 2dly, Another confequence, deducible from our difcovery of the permetals are the vioufnefs of glafs to flame, may be this, that there is caufe to question magifteries of the truth of what is, generally, taken for granted about calcination; and, particularly, of the notion that chymifts have entertain'd about the calces of metals and minerals. For, it does not appear, by our trials, that any proportion, worth regarding, of moift and fugitive parts, was expell'd in

the

the calcination; but it appears very plainly, that, by this operation, the STATICS.? metals gain'd more weight than they loft: fo that the main body of the metal remain'd entire, and was far from being either elementary earth, or a compound of earth and fix'd falt. From which very erroneous hypothefis, the chymifts infer the fweet vitriol of lead, which they call Saccharum Saturni, to be but the fweet falt of it, extracted only by the fpirit of vinegar, which does, indeed, plentifully concur to compofe it. Whence, I conclude, that the calx of a metal, even made per fe, that is, by fire alone, may be, at least in fome cafes, not the Caput mortuum, or Terra. damnata, but a magiftery of it. For, in the fenfe of the moft intelligible of the chymical writers, that is properly a magiftery, wherein the principles are not feparated; but the bulk of the body being preferved, it acquires a new and convenient form, by the addition of the menftruum, or folvent, employ'd about the preparation. Befides, I have, several times, from the calx of lead, reduced actual lead. And, having once taken but about a third or fourth part of the calx of lead, produced by the flame of fpirit of wine, I found, that, without any flux-powder, or other addition, but merely by the application of the flame of highly rectify'd fpirit of wine, there would, in a fhort time, be obtain'd a confiderable proportion of malleable lead; whereof the part I examined, was truly fo.

3dly, One ufe, among the reft, we may make of the foregoing difco- The effects of fire upon bodies, very, regards a controverfy among the corpufcular philofophers. For in clofe glaffes, fome of them think, that when bodies are expofed in clofe veffels to the not wholly owing to the agitation. fire, tho' the igneous corpufcles do not ftay with the bodies they invade ; of the glass. yet they, really, get thro' the pores of the interpofed veffels, and permeate the included bodies in their paffage upwards: whilft others will not allow the igneous corpufcles, which they take to be but vehemently agitated particles of terrestrial matter, to penetrate fuch minute pores as thofe of glass; but fuppofe the operation of the fire to be perform'd by the vehement agitation made of the fmall parts of the glafs, and by them propagated to the included bodies; whofe particles, by this violent commotion, are, greatly alter'd.

But tho' it be probable, that the brisk agitation communicated by the fmall parts of the glafs to thofe of the body contain'd in it, may contribute much to the effect of the fire; and tho', by the fmall increafe of weight we found in our expofed metals, 'tis very likely that far the greater part of the flame was excluded by the clofe texture of the glafs; yet, on the other fide, 'tis plain, that igneous particles pafs'd thro' the glafs, and not only divided and agitated the included bodies, but manifeftly and permanently adhered to them.

tremely volatile.

quite lofe their

4thly, We receive this further information from our experiments, that Particles exbodies very fpirituous, fugitive, and minute, may, by being affociated may, by aliciawith proper particles, tho' of quite another nature, fo change their former ting with others, qualities, as to be arrested by a folid and ponderous body, to that de-volatility. gree, as not to be driven away from it by a fire intenfe enough to melt and calcine metals, For the foregoing trials feem plainly to discover,

that

STATICS. that even the agitated parts of flame, minute enough to pass thro' the pores of glass itself, were, fome way, entangled among the metalline particles of tin and lead; and thereby brought to be fo fix'd, as to endure the heat that kept those metals in fufion, and gradually reduced them to calces: a phenomenon that one would not eafily look for; efpecially confidering how fimple a texture that of lead, or tin, may be, in comparifon of the more elaborate ftructures of many other bodies. And this phenomenon, which fhews us what light and fugitive particles of matter, may permanently, concur to the compofition of ponderous and fix'd bodies, will, perhaps, afford useful hints to the fpeculative; efpecially, if this strict combination of a fpirituous and, fugitive fubftance, with fuchas, being grofs and unwieldy, are lefs fit than organized matter, to entangle, or detain them, be apply'd, as it may be, with advantage, to thofe aggregates of fpirituous corpufcles, and organical parts, that make up the bodies of plants and animals. And this hint may fuggeft a confiderable inference to be drawn from the operation of the fun-beams on appropriated fubjects; fuppofing it to prove like that of flame on tin and lead

*The following queries of Sir Ifaac Newton, give us the beft light we have into the nature of fire and flame. "Is not," fays that great philofopher, "fire a body, "heated fo hot, as to emit light copiouf86 ly? For, what else is a red-hot iron, "than fire? And, what else is a burning "coal, than red-hot wood? Is not flame "a vapour, fume, or exhalation, heated "red-hot; that is, fo hot as to fhine? "For, bodies do not flame, without emit"ting a copious fume; and this fume burns "in the flame. The Ignis fatuus is a vapour, "fhining without heat: and, is there not "the fame difference between this vapour, "and flame, as between rotten wood, "fhining without heat, and burning coals "of fire? In diftilling hot fpirits, if the "head of the ftill be taken off, the vapour, "which afcends out of the ftill, will take "fire at the flame of a candle, and turn "into flame; and the flame will run a"long the vapour, from the candle, to the "ftill. Some bodies, heated by motion,

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or fermentation, if the heat grow in"tenfe, fume copioufly; and, if the heat "be great enough, the fumes will shine,

and become flame. Metals, in fufion, "do not flame for want of a copious "fume. Salt-petre fumes copiously, and

thereby flames. All flaming bodies, as "oil,tallow,wax, wood, foffil, coals, pitch, "and fulphur, by flaming wafte, and vanish into burning fmoke; which fmoke, if

"the flame be put out, is very thick, and "vifible; and fometimes fmells ftrongly : "but, in the flame, it lofes its smell, by

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burning and, according to the nature "of the fmoke, the flame is of several co"lours; as that of fulphur, blue; that of copper, open'd with fublimate, green; "that of tallow, yellow; that of camphire, "white. Smoke paffing thro' flame, can"not but grow red-hot; and, red-hot "fmoke can have no other appearance " than that of flame. When gun-powder "takes fire, it goes away into flaming "fmoke. For the charcoal and fulphur,

easily take fire, and fet fire to the nitre; and the fpirit of the nitre, being "thereby rarified into vapour, rushes out, "with explosion, much after the manner "that the vapour of water rushes out of

an eolipile; the fulphur, alfo, being vo"latile, is converted into vapour, and

augments the explofion. And, the acid "vapour of the fulphur, namely, that "which diftils under a glafs-bell, into oil "of fulphur, entering violently into the "fixed body of the nitre, fets loose the "Spirit of the nitre, and excites a great "fermentation, whereby the heat is far"ther augmented, and the fixed body of "the nitre is alfo rarified into fume; " and the explosion is, thereby, made

more vehement, and quick. For, if falt "of tartar be mixed with gun-powder "and the mixture be warm'd till it takes

"fire, the explosion will be more violent, " and quick, than that of gun-powder a"lone; which cannot proceed from any "other caufe, than the action of the va

pour of the gun-powder upon the falt "of tartar, whereby the falt is rarified. "The explosion of gun-powder arifes, "therefore, from the violent action, "whereby all the mixture, being quickly "and vehemently heated, is rarified, and 'converted into fume and vapour; which

vapour, by the violence of that action, "becoming fo hot as to fhine, appears "in the form of flame."

The following query is fo beautiful, and opens fuch a glorious fcene, that I should be tempted to add it, tho' it bore a lefs relation, than it does, to the present subje&t.

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pours and exhalations which arife from STATICS. "them? For, if water be made warm, in " any pellucid veffel emptied of air, that water, in the vacuum, will bubble and "boil, as vehemently as it would in the open air, in a veffel fet upon the fire, "till it conceives a much greater heat. "For, the weight of the incumbent at"mofphere, keeps down the vapours, and "hinders the water from boiling, till it grow much hotter than is requifite to "make it boil in vacuo. Alfo, a mixture "oftin and lead, being put upon a red-hot “iron, in vacuo, emits a fume and flame; "but the fame mixture, in the open air, "by reafon of the incumbent atmosphere, "does not fo much as emit any fume, "which can be perceiv'd by fight. In "like manner, the great weight of the "atmosphere, which lies upon the globe "of the fun, may hinder bodies there from "rifing up, and going away from the fun, "in the form of vapours, and fumes, un"lefs by means of a far greater heat than that which, on the furface of our earth, "would very eafily turn them into vapours and fumes. And the fame great weight may condense those vapours, and "exhalations, as foon as they fhall, at any time, begin to afcend from the fun, "and make them prefently fall back again into him; and, by that a&tion, in"crease his heat, much after the fame

"Do not " continues the fame great author, "large bodies conferve their heat "the longeft; their parts heating one a"nother? And, may not a great, denfe, "and fixed body, when heated beyond "a certain degree, emit light fo copiously," << as, by the emiffion, and re-action of its "light, and the reflexions, and refractions "of its rays, within its pores, to grow "ftill hotter, till it comes to a certain pe"riod of heat; fuch as is that of the fun? "And, are not the fun, and fixed stars, "great earths, vehemently hot; whofe "heat is conferved by the greatness of the "bodies, and the mutual action, and re"action between them, and the light "which they emit; and whose parts are "kept from fuming away, not only by "their fixity, but, alfo, by the vast weight

and denfity of the atmospheres, incum"bent upon them; and very ftrongly compreffing them, and condenfing the va

66

manner that, on our earth, the air in"creases the heat of a culinary fire. And "the fame weight may hinder the globe "of the fun from being diminish'd; unless

by the emiffion of light, and a very "fmall quantity of vapours and exhala"tions. Newton. Optic. p. 316-319.