A PRÆFACE INTRODUCTORY To the following Treatise.

either explicate or prove the Chymical Theory better than ordinary Chymists have done, or by enriching us with some of their nobler secrets to evince that Their art is able to make amends even for the deficiencies of their Theory: And thus much I shall here make bold to add, that we shall much undervalue Chymistry, if we imagine, that it cannot teach us things farr more useful, not only to Physick but to Philosophy, than those that are hitherto known to vulgar Chymists. And yet as for inferiour Spagyrists themselves, they have by their labours deserv’d so well of the Common-wealth of Learning, that methinks ’tis Pity they should ever misse the Truth which they have so industriously sought. And though I be no Admirer of the Theorical Part of their Art, yet my conjectures will much deceive me, if the Practical Part be not much more cultivated than hitherto it has been, and do not both employ Philosophy and Philosophers, and help to make men such. Nor would I that have been diverted by other Studies as well as affairs, be thought to pretend being a profound Spagyrist, by finding so many faults