BRADLEY, Dr. JAMES, one of the most distinguished astronomers and discoverers of any time or country. wits b. at Sherborne. in Gloucestershire, in 1692. He received his early education at a boarding-school at North Leach, whence, being destined for the church, he proceeded to Oxford. Soon after graduating, he obtained successively the livings of Bridslow and of Welfrie. in Pembrokeshire; brit there is reason to fear that Ins mathematical pursuits considerably distracted his attention from his clerical duties. Devoting himself to mathematics and astronomy, he soon exhibited such a genius for these pursuits as to win the friendship of all the leading mathematicians of his time, among others, of the great Isaac Newton, and to get elected a member of the royal societY. About the time of his election, 1721. lie became, in his 29th year, Savilian professor of astronomy at Oxford. resigned his livings, and devoted himself wholly to science. In 1727, lie published his theory of the aberration of the fixed stars, eon taining the important discovery of the aberration of light, to which. it is related. he was led somewhat by accident, as sir Isaac Newton was to the theory of gravitation.
What suggested this discovery to B., it is said, was the observation that the vane of a yacht in which he was sailing 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 yacht's motion. This led him
to a train of thought resulting in the proposition, that the direction in which we see a star is not that iu which it actually lies, but inclined to it by an angle depending on the direction of the earth's motion round the sun at the time of the observation, and the ratio of its velocity to that of light. See AnnmutAnox. Three years after this publica tion, 13. became lecturer on astronomy and physics at the Oxford His next discovery was that the inclination of the earth's axis to the ecliptic is not constant, a fact including the explanation of the procession of the equinoxes and the natation of the earth's axis. This constitutes a. great epoch in astronomy. Latterly, 13. became regius professor of astronomy at Greenwich, where, by his observations, he still further enriched the science. He declined the living of the parish of Greenwich, which was offered to him, and was favored by the crown with a pension of £250 a year for his services to commerce and navigation. Towards the end of his life, II. NAllS elected mem ber successively of almost all the leading scientific societies in Europe. He died on the 2d ofJuly, 1762, in his 70th year. B. 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. No man ever better merited the title of a great astronomer.