Concrete is made up, being boyl’d up together are easily brought to mingle and incorporate into one Mass; but by another and further degree of Heat the same Mass may be again divided into an oleagenous, an aqueous, a Saline, and an Earthy part. And so we may observe that impure Silver and Lead being expos’d together to a moderate Fire will thereby be colliquated into one Mass, and mingle per minima, as they speak, whereas a much vehementer Fire will drive or carry off the baser Metals (I mean the Lead, and the Copper or other Alloy) from the Silver, though not, for ought appears, separate them from one another. Besides, when a Vegetable abounding in fixt Salt is analyz’d by a naked Fire, as one degree of Heat will reduce it into Ashes, (as the Chymists themselves teach us) so, by only a further degree of Fire, those Ashes may be vitrified and turn’d into Glass. I will not stay to examine how far a meere Chymist might on this occasion demand, If it be lawful for an Aristotelian to make Ashes, (which he mistakes for meere Earth) pass for an Element, because by one degree of Fire it may be
