before, then are those which suffice to discriminate the Chymists Principles from one another. We are next to Consider, whether in the Anatomy of mixt Bodies, that which Chymists call the Mercurial part of them be un-compounded, or no. But to tell You True, though Chymists do Unanimously affirm that their Resolutions discover a Principle, which they call Mercury, yet I find them to give of it Descriptions so Differing, and so AEnigmaticall, that I, who am not asham'd to confess that I cannot understand what is not sence, must acknowledge to you that I know not what to make of them. _Paracelsus_ himself, and therefore, as you will easily believe, many of his Followers, does somewhere call that Mercury which ascends upon the burning of Wood, as the Peripateticks are wont to take the same smoke for Air; and so seems to define Mercury by Volatility, or (if I may coyne such a Word) Effumability. But since, in this Example, both Volatile Salt and Sulphur make part of the smoke, which does indeed consist also both of Phlegmatick and Terrene Corpuscles, this Notion is not to be admitted; And I find that the more sober Chymists themselves disavow it. Yet to shew you how little of clearness we are to expect in the accounts even of latter _Spagyrists_, be pleas'd to take notice, that _Beguinus_, even in his _Tyrocinium Chymicum_,[20] written for the Instruction of Novices, when he comes to tell us what are meant by the _Tria Prima_, which for their being Principles ought to be defin'd the more accurately and plainly, gives us this Description of Mercury; _Mercurius_ (sayes he) _est liquor ille acidus, permeabilis, penetrabilis, aethereus, ac purissimus, a quo omnis Nutricatio, Sensus, Motus, Vires, Colores, Senectutisque Praeproperae retardatio._ Which words are not so much a Definition of it, as an _Encomium_: and yet _Quercetanus_ in his Description of the same Principle adds to these, divers other _Epithets_. But both of them, to skip very many other faults that may be found with their Metaphoricall Descriptions, speak incongruously to the Chymists own Principles. For if Mercury be an Acid Liquor, either Hermetical Philosophy must err in ascribing all Tasts to Salt, or else Mercury must not be a Principle, but Compounded of a Saline Ingredient and somewhat else. _Libavius_, though he find great fault with the obscurity of what the Chymists write concerning their Mercurial Principle, does yet but give us such a Negative Description of it, as _Sennertus_, how favourable soever to the _Tria Prima_, is not satisfi'd with. And this _Sennertus_ Himself, though the Learnedst Champion for the Hypostatical Principles, does almost as frequently as justly complain of the unsatisfactoriness of what the Chymists teach concerning their Mercury; and yet he himself (but with his wonted modesty) Substitutes instead of the Description of _Libavius_, another, which many Readers, especially if they be not Peripateticks, will not know what to make of.