James Bradley
James Bradley was an English
astronomer, Astronomer Royal from 1742. He is best known for discovering the
aberration of light.
Encyclopedia
James Bradley was an English
astronomer, Astronomer Royal from 1742. He is best known for discovering the
aberration of light.
Life & work
Bradley was born at Sherborne, near
Cheltenham in
Gloucestershire, in March 1693. He entered
Balliol College, Oxford, on March 15 1711, and took degrees of B.A. and M.A. in 1714 and 1717 respectively. His early observations were made at the rectory of Wanstead in Essex, under the tutelage of his uncle, the Rev. James Pound and was elected a fellow of the
Royal Society on November 6 1718.
He took orders on becoming vicar of Bridstow in the following year, and a small sinecure living in
Wales was also procured for him by his friend Samuel Molyneux. He resigned his ecclesiastical preferments in 1721, when appointed to the Savilian chair of astronomy at
Oxford, while as reader on experimental
philosophy he delivered 79 courses of lectures at the
Ashmolean Museum.
His memorable discovery of the aberration of light was announced to the Royal Society in January 1729 . The observations upon which it was founded were made at Molyneux’s house on Kew Green. He did not announce the supplementary detection of
nutation until February 14 1748 , when he had tested its reality by minute observations during an entire revolution of the moon’s nodes. In 1742, he had been appointed to succeed
Edmund Halley as Astronomer Royal; his enhanced reputation enabled him to apply successfully for a set of instruments costing £1000; and with an 8-foot quadrant completed for him in 1750 by John Bird, he accumulated at
Greenwich in ten years materials of inestimable value for the reform of astronomy. A crown pension of £250 a year was conferred upon him in 1752.
He retired in broken health, nine years later, to the Cotswold village of Chalford in
Gloucestershire, where he died at Skiveralls House on 13 July 1762. The publication of his observations was delayed by disputes about their ownership; but they were finally issued by the
Clarendon Press, Oxford, in two folio volumes . The insight and industry of
Friedrich Wilhelm Bessel were, however, needed for the development of their fundamental importance.
References
Rigaud’s Memoir prefixed to
Miscellaneous Works and Correspondence of James Bradley, D.D. , is practically exhaustive. Other sources of information are:
New and General Biographical Dictionary, xii. 54 ;
Biog. Brit. ; Fouchy’s
Eloge,
Paris Memoirs , p. 231 ; Delambre’s
Hist. de l’astronomie au 18e siècle, p. 413.
