Illustrious natural philosopher, born in Woolsthorpe, near Grantham, in Lincolnshire; entered Trinity College, Cambridge, in 1661, where he applied himself specially to the study of mathematics, invented the method of fluxions (q. v .), and began to theorise on gravitation, graduating in 1667, and becoming professor of Mathematics in 1669; failing at first, from a mistaken measurement given of the earth's diameter, in his attempts to establish the theory referred to, he set himself to the construction of telescopes, and discovered the composition of light; shortly after this, hearing of a correction of the measurement required, he renewed his study of gravitation, and made his theory good in a series of papers communicated to the Royal Society, though it was not till 1687, encouraged by Halley, he gave the complete demonstration in his "Principia" to the world; in 1695 he was made Warden of the Mint, and afterwards Master, a post he held till his death; his works were numerous, and he wrote on prophecy as well as treatises on science (1642-1727).