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 sweet 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 some cafes, not the Caput mortuum, or Terra damnata, but a magiftery of it. For, in the fenfe of the most 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 feveral 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 spirit 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 examin'd was truly fo.. 3dly, One use, among the reft, we may make of the foregoing difco The effects of very, regards a controverfy among the corpufcular philofophers. For fireupon bodies, in clofe glaffes, fome of them think, that when bodies are expofed in clofe veffels to the not wholly owfire, tho' the igneous corpufcles do not ftay with the bodies they invade; ing to the agiyet they really get thro' the pores of the interpofed veffels, an permeate tation of the the included bodies in their paffage upwards; whilft others will not allow glass. the igneous corpufcles, which they take to be but vehemently agitated particles of terreftrial matter, to penetrate fuch minute pores as thofe of glafss; 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 brifk 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 increase of weight we found in our expofed metals, 'tis very likely that far the greater part of the flame was excluded by the close texture of the glass; yet, on the other fide, 'tis plain, that igneous par icles pafs'd thro' the glafs, and not o: ly di ided and agitated the included bodies, but manifeftly and permanently adhered to them.. vola 4thly, We receive this further information from our experiments, that Particles exbodies very fpirituous, fugitive, and minute, may, by being affociated tremely va tile may by af. with proper particles, tho' of quite another nature, fo change their former fociating with qualities, as to be arrested by a folid and ponderous body, to that de- others, quitelofe gree, as not to be driven away from it by a fire intenfe enough to melt their volatiliand calcine metals. For the foregoing trials feem plainly to discover, that ty. STATICS. that even the agitated parts of flame, minute enough to pass through the pores of glafs 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 thofe 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 comparison 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 ufeful hints to the fpeculative; efpecially, if this ftrict combination of a spirituous and fugitive fubftance with fuch as being grofs and unweildy, 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.* smoke, 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, "eafily take fire, and fet fire to the "nitre; and the fpirit of the nitre being 66 66 thereby rarify'd into vapour, rushes out, "with explofion, much after the manner "that the vapour of water rushes out of an æolipile; the fulphur, also, being vo"latile, is converted into vapour, and augments the explosion. 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 fpirit 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 explofion 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 66 66 fire, the explofion 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 va66 pour of the gun powder upon the falt "of tartar, whereby the falt is rarified. "The explosion of gun-powder ariles, "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 shine, appears in "the form of flame." 66 46 The following query is fo beautiful, and opens fuch a glorious fcene, that I should be tempted to add it, tho' it bore a less relation than it does, to the prefent subject. "Do not" continues the fame great author," large bodies conferve their heat the "longeft; their parts heating one ano"ther? And may not a great, dense, and "fixed body, when heated beyond a cer"tain 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 hot 66 66 ter, till it comes to a certain period of "heat; fuch as is that of the fun? And vacuum, will bubble and boil, as vehe"mently as it would in the open air, in a "veffel fet upon the fire, till it conceives much greater heat. For the weight of "the incumbent atmosphere, keeps down "the vapours, and hinders the water from "boiling, till it grow much hotter than 66 66 66 a is requifite to make it boil in vacuo. "Alfo, a mixture of tin 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 reason of the "incumbent atmosphere, does not fo much as emit any fume, which can be percei"ved 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, unless by means of a "far greater heat than that which, on the "furface of our earth, would very easily "turn them into vapours and fumes. And "the fame great weight may condenfe "thofe vapours, and exhalations, as foon 66 66 66 as they fhall, at any time, begin to af "cend from the fun, and make them pre"fently fall back again into him; and, by "that action, increase his heat, much after "the fame manner that, on our earth, the "air increases 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 exhalations. Newton. Optic. p. 316,-319. 66 VOL. II. Fff PNEUM A STATICS. that even the agitated parts of flame, minute enough to pass through the pores of glafs 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 thofe 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 comparison 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 ufeful hints to the fpeculative; efpecially, if this strict combination of a fpirituous and fugitive fubftance with fuch as being grofs and unweildy, 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.* long the vapour, ftom the candle to the or fermentation, if the heat grow in- fume. Salt petre fumes copiously, and "thereby flames. All faming bodies, as "oil, tallow, wax,wood, foflil, coals, pitch, "and fulphur, by flaining wafte, and vanish "into burning fmoke; which smoke, if longeft; their parts heating one ano"ther? And may not a great, dense, and "fixed body, when heated beyond a cer"tain 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 hot 66 66 ter, till it comes to a certain period of "heat; fuch as is that of the fun? And "are not the fun, and fixed ftars, great "earths, vehemently hot; whofe heat is "conferved by the greatness of the bodies, " and the mutual action, and re-action be"tween them, and the light which they "emit; and whofe parts are kept from "fuming away, not only by their fixity, "but, alfo, by the vaft weight and density "of the atmospheres, incumbent upon "them; and very strongly compreffing them, and condenfing the vapours and "exhalations which arife from them? For STATICS. "if water be made warm, in any pellucid "veffel emptied of air, that water, in the "vacuum, will bubble and boil, as vehe"mently 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 atmosphere, keeps down "the vapours, and hinders the water from 46 66 boiling, till it grow much hotter than "is requifite to make it boil in vacuo. "Alfo, a mixture of tin and lead, being put upon a red-hot iron, in vacuo, emits a fume and flame; but the fame mix"ture, in the open air, by reafon of the "incumbent atmosphere,does not fo much "as emit any fume, which can be percei"ved by fight. In like manner, the great "weight of the atmofphere, 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, unless by means of a "far greater heat than that which, on the "furface of our earth, would very easily "turn them into vapours and fumes. And "the fame great weight may condense "those vapours, and exhalations, as foon 66 66 66 66 as they fhall, at any time, begin to af"cend from the fun, and make them pre"fently fall back again into him; and, by "that action, increase his heat, much after "the fame manner that, on our earth, the "air increases 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 exha"lations. Newton. Optic. p. 316,-319. VOL. II. Fff PNEUMA |