r i4 "The Complete Engliih 'Difpenfatorf. Part I.

whofe Parts, with refpeif. to Denfi-ty and Surface, are extremely diffe-rent from one another, ibme beingcarry'd off by the Force of the Heat,and others chang'd as to Figure orPofition, muff, be forc'd to appearin another Form : For they cannotrecover their original Phafes, un-lefs every Particle could reinftate it-felf in that very Situation it had be-fore; which may be hinder'd infiniteWays, as may eafily be experiencein Heterogeneous Bodies fuch asVegetables , and all Minerals , aslikewife the bafer fort of Metals.Thus every Plant is turn'd to Afijes;and Vitriol, when all its Moiftureis dry'd away, becomes Chalcan-thum ; and Clay, by the Heat ofthe Furnace, hardens into Tiles andBricks.

Therefore the Difference which isobfèrv'd, even in Homogeneous Bo-dies, after Liquefaction, is no wayto be accounted for, but from theChangeablenefs of Surface in itsParts : For thole Bodies, whole Partsconftantly retain the fame Surfaces,never lofe their Form ; but others,by having the Surfaces of their Partsalter'd, acquire a different Texture,and put on another Appearance.

Fluidity being in this manner ex-plain'd, Calcination may, withoutDifficulty, be underflood ; which,in many Inflances, is only the Effectof a longer Liquefaction. For whenthe Fufion is longer continu'd, notonly the more iubtile Particles of theBody itfelf fly off, but the Particlesof the Fire likewife infinuate them-felves in fuch Multitudes, and areio dilpers'd and blended throughoutall its Subftance, that the Fluidity,which was firft caus'd by the Fire,can no longer fubfift. From thisUnion arifes a third Kind of Body,which being very porous and brit-tle, is eafily reduc'd to Ponder : for

the Fire having penetrated everywhere into the Pores of the Body,the Particles are both kept from mu-tual Contact, and divided into mi-nute Atoms; fo that they are eafilyreduced to the fineft Pouder.

From the foregoing 'tis manireft,that not only the Parts of the Bodycalcin'd are much broken and ra-rify'd, but that the very Increafe ofthe Weight itfèlf proceeds from theFire. The Gravity of crude Lead,if compared to Water, is as 11 ¿ toi ; but that of calcin'd Lead is as oto 1. So the Proportion of calcin'dCoffer to Water, is but f^ T ; butthat of crude is S|. The Propor-tion of White Lead to Lead itfelfcomes out ftill lefs, i. e. fubtriple.But four Ounces of Regulus oí An-timony, if put in Fufion for an hourand half, will gain two Drams anda half,- tho' in the mean time a mul-titude of Effluvia go off in Vapour.Hence it appears, that the abibluteGravity is increas'd indeed by Calci-nation, but the Specific is leffen'd :The Reafon of which is this, Thatthe Particles of the Body, divided bythe Fire, and feparated from mutualContaft, are diffufed into a largerBulk. But the Particles of Fire,which are much lighter than thecalcin'd Body, being every wheremix'd with it, and dilpers'd thro' itsPores, leffen the ipecific, and in-creafe abiblute Gravity.

But however the Particles of Bo-dies are divided and feparated byCalcination, fo as to lofe their an-tient Appearance ; yet many Me-tals, and fome Minerals, whofeParts are moftly Homogeneous,don't fem to lofe their Nature withtheir Form. For Gold, Silver, and6)uickfilver, cannot be fo deftroy'dby all the Calcining imaginable, butthat they may with very little trou-ble be reviv'd. So out of Salt ofa Tin,