violence of the Fire, that most Chymists think it a Body more undestroyable then Gold it self. For if the Artificer can so firmly unite such comparative gross Particles as those of Earth and Salt that make up common Ashes, into a Body indissoluble by Fire; why may not Nature associate in divers Bodies the more minute Elementary Corpuscles she has at hand too firmly to let them be separable by the Fire? And on this Occasion, _Eleutherius_, give me leave to mention to you two or three sleight Experiments, which will, I hope, be found more pertinent to our present Discourse, than at first perhaps they will appear. The first is, that, having (for Tryals sake) put a quantity of that Fugitive Concrete, Camphire, into a Glass Vessel, and plac'd it in a gentle Heat, I found it (not leaving behinde, according to my Estimate, not so much as one Grain) to sublime to the Top of the Vessel into Flowers: which in Whiteness, Smell, &c. seem'd not to differ from the Camphire it self. Another Experiment is that of _Helmont_, who in several places affirms, That a Coal kept in a Glass exactly clos'd will never be calcin'd to Ashes, though kept never so long in a strong Fire. To countenance which I shall tell you this Tryal of my own, That having sometimes distilled some Woods, as particularly Box, whilst our _Caput mortuum_ remain'd in the Retort, it continued black like Charcoal, though the Retort were Earthen, and kept red-hot in a vehement Fire; but as soon as ever it was brought out of the candent Vessel into the open Air, the burning Coals did hastily degenerate or fall asunder, without the Assistance of any new Calcination, into pure white Ashes. And to these two I shall add but this obvious and known Observation, that common Sulphur (if it be pure and freed from its Vinager) being leasurely sublim'd in close Vessels, rises into dry Flowers, which may be presently melted into a Bodie of the same Nature with that which afforded them. Though if Brimstone be burnt in the open Air it gives, you know, a penetrating Fume, which being caught in a Glass-Bell condenses into that acid Liquor called Oyl of Sulphur _per Campanam_. The use I would make of these Experiments collated with what I lately told you out of _Agricola_ is this, That even among the Bodies that are not fixt, there are divers of such a Texture, that it will be hard to make it appear, how the Fire, as Chymists are wont to imploy it, can resolve them into Elementary Substances. For some Bodies being of such a Texture that the Fire can drive them into the cooler and less hot part of the Vessels wherein they are included, and if need be, remove them from place to place to fly the greatest heat, more easily than it can divorce their Elements (especially without the Assistance of the Air) we see that our Chymists cannot Analyze them in close Vessels, and of other compound Bodies the open Fire can as little separate the Elements. For what can a naked Fire do to Analyze a mixt Bodie, if its