The First Part.

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 component Principles be so minute, and so strictly united, that the Corpuscles of it need less heat to carry them up, than is requisite to divide them into their Principles. So that of some Bodies the Fire cannot in close Vessels make any Analysis at all, and others will in the open Air fly away in the Forms of Flowers or Liquors, before the Heat can prove able to divide them into their Principles. And this may hold, whether the various similar parts of a Concrete be combin’d