HARRIOT or HARRIOTT, THOMAS English mathematician and astronomer, was born at Oxford in 1560. After studying at St. Mary hall, Oxford, he became tutor to Sir Walter Raleigh, who appointed him in 1585 to the office of geographer to the second expedition to Virginia. Harriot pub lished an account of this expedition in 1588, which was afterwards reprinted in Hakluyt's Voyages. On his return to England (1587) he resumed his mathematical studies. He materially assisted the development of algebra, and introduced symbols and notation still used, e.g., for xxx. A manuscript of Harriot's entitled Ephemeris chrysometria is preserved in Sion college, near Lon don; and his Artis analyticae praxis ad aequationes algebraicas resolvendas was published at London in 1631. He died in London on July 2, 1621.