Since that time the Art is become so extensive, by the numerous discoveries which Chymists have already made, and are daily making, that large volumes are required to contain a complete Treatise on the subject. In short, Chymistry may now, in some degree, be compared to Geometry: each of these Sciences takes in a most ample field of inquiry, which every day enlarges very considerably; from each are derived several Arts, not only useful but even necessary to Society; each hath its Axioms and its undeniable principles, either demonstrated from internal evidence, or founded on constant experience; so that the one, as well as the other, may be reduced to certain fundamental truths, on which all the rest are built. These fundamental truths connected together, and laid down with order and precision, form what we call the Elements of a Science. It is well known that there are many such works relating to Geometry, but it is not so with regard to Chymistry; there being very few books which treat of this Science in an Elementary manner. Yet it must be owned, that performances of this kind are exceedingly useful. Many who have a relish for the Sciences, but have not leisure to read elaborate Works which treat of them minutely, are glad to meet with a book from which, without sacrificing too much of their time, or neglecting their ordinary business, they may obtain a taste or just notion of a Science that is not their principal study. Those who incline to go farther, and learn more, may, by reading an elementary tract, be enabled to understand Authors, who, as they commonly write only for proficients in the Art, are obscure and hardly intelligible to mere beginners. Nay, I presume to say, that an Elementary Treatise of Chymistry may prove a very useful book, even to those who have made some progress in the Science: for as it contains only the fundamental propositions, and indeed is an abstract of the whole Art, it may help them to recollect the most important parts of what they have read in many different works, and fix in their memoirs the most essential truths, which might else be either confounded with others, or entirely forgot. And these are the motives which determined me to compose the Work which I now offer to the Public.