Bradley, JAMES

Bradley, JAMES, astronomer, was born at Sherborne, Gloucestershire, in 1693; from Northleach grammar-school passed in 1711 to Balliol College, Oxford. The scientific bent of his mind was moulded and directed by his uncle, the Rev. James Pound, of Wanstead, Essex, and in conjunction with him his first discoveries were made. Devoting himself to mathematics and astronomy, he soon exhibited such a genius for these pursuits as won him the friendship of all the leading mathematicians of his time, including Halley and Sir Isaac Newton, and secured his election to the Royal Society in 1718. In 1719 he obtained the vicarage of Bridstow, and in 1720 a sinecure rectory in Pembrokeshire; but he resigned both in 1721 on his election to the Savilian professorship of Astronomy at Oxford. In 1729 he published his theory of the aberration of the fixed stars, containing the important discovery of the aberration of light—suggested by the observation that the vane of a boat in which he was sailing on the Thames in 1728 never lay in the line of the wind, but was always inclined to it at an angle depending on the line and amount of the boat's motion. See ABERRATION, and ASTRONOMY. Three years after this publication Bradley became lecturer on Astronomy and Physics at the Oxford Museum. His next discovery, published in 1748, after twenty years' research, was that the inclination of the earth's axis to the ecliptic is not constant, a fact including the explanation of the precession of the equinoxes and the nutation of the earth's axis. In 1742 Bradley succeeded Halley as regius professor of Astronomy at Greenwich, where, by his observations, he still further enriched the science. His refusal of the vicarage of Greenwich was compensated in 1752 by a crown pension of £250 a year. He died at Chalford, Gloucestershire, 13th July 1762. Bradley is described as having been gentle, modest, compassionate, and liberal; little given to speaking or writing, from diffidence and the fear of hurting his reputation. He has been called the founder of observational astronomy, and no man ever better merited the title of a great astronomer. His astronomical observations, which numbered about 60,000, fill two folio vols. (1798-1805). Bessel was able in 1818, from Bradley's labours, to deduce a catalogue of 3222 stars for the epoch of 1755. See Rigaud's Miscellaneous Works and Correspondence of Bradley, with Memoir (1832).