ISAAC (1630-1677).-Divine, scholar, and mathematician, _s._ of a linen-draper in London, was _ed._ at Charterhouse, Felsted, Peterhouse, and Trinity Coll., Cambridge, where his uncle and namesake, afterwards Bishop of St. Asaph, was a Fellow. As a boy he was turbulent and pugnacious, but soon took to hard study, distinguishing himself in class