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THE
Author's Preface
INCE the ancients (as we are told by Pappus) made great account of the ſcience of mechanics in the inveſtigation of natural things; and the moderns, laying aſide ſubſtantial forms and occult qualities, have endeavored to ſubject the phenomena of nature to the laws of mathematics, I have in this treatiſe cultivated Mathematics ſo far as it regards Philoſophy. The ancients considered Mechanics in a twofold reſpect; as rational, which proceeds accurately by demonſtration, and practical. To practical Mechanics all the manual arts belong, from which Mechanics took its name. But as artificers do not work with perfect accuracy, it comes to paſs that Mechanics is so diſtinguished from Geometry, that what is perfectly
