HARRIOT, or Harriott, Thomas (1560-1621), an English mathematician and astronomer, was born at Oxford in 1560. After studying at St Mary’s Hall, Oxford, where he took his bachelor’s degree in 1579, he became tutor to Sir Walter Raleigh, who in 1585 appointed him to the office of geographer to the second expedition to Virginia. Harriot published an account of this expedition in 1588, and the work was afterwards reprinted in Hakluyt’s Voyages. On his return to England after an absence of two years, he resumed his mathematical studies with zeal and success; and having made the acquaintance of Henry Percy, earl of Northumberland, distinguished for his patronage of men of science, he received from him a yearly pension of £.120. He died at London 2d July 1621, after having suffered much from a cancer in the lip, occasioned it is supposed by a habit he had contracted of holding in his mouth instruments of brass often charged with verdigris. A manuscript of Harriot’s entitled “Ephemeris Chrysome-tria” is preserved in Sion College; and his Artis Analy- ticoe Praxis ad Aequationes Algebraicas resolvendas was published at London in 1631. An account of his contributions to the science of algebra will be found in the article Algebra, vol. i. p. 514; and Wallis’s History of Algebra (1685) may also be consulted. From some papers of Harriot’s discovered in 1784 it would appear that he had either procured a telescope from Holland, or divined the construction of that instrument, and that he coincided in point of time with Galileo in discovering the spots on the sun’s disk.