lizate Salt and the Terrestrial Residue of the Ashes are Incorporated with pure Sand, and by Vitrification made one permanent Body, (I mean the course or greenish sort of Glass) that mocks the greatest Violence of the Fire, which though able to Marry the Ingredients of it, yet is not able to Divorce them. I can shew you some pieces of Glass which I saw flow down from an Earthen Crucible purposely Expos’d for a good while, with Silver in it, to a very vehement Fire. And some that deal much in the Fusion of Metals Informe me, that the melting of a great part of a Crucible into Glass is no great Wonder in their Furnaces. I remember, I have Observ’d too in the Melting of great Quantities of Iron out of the Oar, by the Help of store of Charcoal (for they Affirm that Sea-Coal will not yield a Flame strong enough) that by the prodigious Vehemence of the Fire, Excited by vast Bellows (made to play by great Wheels turn’d about by Water) part of the Materials Expos’d to it was, instead of being Analyz’d, Colliquated, and turn’d into a Dark, Solid and very Ponderous Glass, and that in such Quan-
