A PRÆFACE INTRODUCTORY To the following Treatise.

in the Doctrine wherein the Generality of Chymists scruples not to Acquiesce: For besides that ’tis most commonly far easier to frame Objections against any propos’d Hypothesis, than to propose an Hypothesis not lyable to Objections (besides this I say) ’tis no such great matter, if whereas Beginners in Chymistry are commonly at once imbu’d with the Theory and Operations of their profession, I who had the good Fortune to Learn the Operations from illiterate Persons, upon whose credit I was not Tempted to take up any opinion about them, should consider things with lesse prejudice, and consequently with other Eyes than the Generality of Learners; And should be more dispos’d to accommodate the Phænomena that occur’d to me to other Notions than to those of the Spagyrists. And having at first entertain’d a suspition That the Vulgar Principles were lesse General and comprehensive, or lesse considerately Deduc’d from Chymical Operations, than was believ’d; it was not uneasie for me both to Take notice of divers Phænomena, overlook’d by prepossest Persons, that seem’d not to suite so well with the Hermetical Doctrine; and, to devise some Experiments likely to furnish me with Objections against it,