BRADLEY (Dr. James)

, a celebrated English astronomer, the third son of William Bradley, was born at Sherborne in Gloucestershire in the year 1692. He was fitted for the university at Northleach in the same county, at the boarding school of Mr. Egles and Mr. Brice. From thence he was sent to Oxford, and admitted a commoner of Baliol college March 15, 1710; where he took the degree of bachelor the 14th of October 1714, and of master of arts the 21st of January 1716. His friends intending him for the church, his studies were regulated with that view; and as soon as he was of a proper age to receive holy orders, the bishop of Hereford, who had conceived a great esteem for him, gave him the living of Bridstow, and soon after he was inducted to that of Landewy Welfry in Pembrokeshire.

He was nephew to Mr. Pound, a gentleman well known in the learned world, by many excellent astronomical and other observations, and who would have enriched it much more, if the journals of his voyages had not been burnt at Pulo Condor, when the place was set on fire, and the English who were settled there cruelly massacred, Mr. Pound himself very narrowly escaping with his life. With this gentleman, at Wanstead, Mr. Bradley passed all the time that he could spare from the duties of his function; being then sufficiently acquainted with the mathematics to improve by Mr. Pound's conversation. It may easily be imagined that the example and conversation of this gentleman did not render Bradley more fond of his profession, to which he had before no great attachment: he continued however as yet to fulfil the duties of it, though at this time he had made such observations as laid the foundation of those discoveries which afterward distinguished him as one of the greatest astronomers of his age. These observations gained him the notice and friendship of the lord chancellor Macclesfield, Mr. Newton afterward Sir Isaac, Mr. Halley, and many other members of the Royal Society, into which he was soon after elected a member.

Soon after, the chair of Savilian professor of astro- nomy at Oxford became vacant, by the death of the celebrated Dr. John Keil; and Mr. Bradley was elected to succeed him on the 31st of October 1721, at 29 years of age: his colleague being Mr. Halley, who was professor of geometry on the same foundation. Upon this appointment, Mr. Bradley resigned his church livings, and applied himself wholly to the study of his favourite science. In the course of his observations, which were innumerable, he discovered and settled the laws of the alterations of the fixed stars, from the progressive motion of light, combined with the earth's annual motion about the sun, and the nutation of the earth's axis, arising from the unequal attraction of the sun and moon on the different parts of the earth. The former of these effects is called the aberration of the fixed stars, the theory of which he published in 1727; and the latter the nutation of the earth's axis, the theory of which appeared in 1737: so that in the space of about 10 years, he communicated to the world two of the finest discoveries in modern astronomy; which will for ever make a memorable epoch in the history of that science. See Aberration and Nutation.

In 1730 our author succeeded Mr. Whiteside, as lecturer in astronomy and experimental philosophy in the Museum at Oxford: which was a considerable emolument to him, and which he held till within a year or two of his death; when the ill state of his health induced him to resign it.

Our author always preserved the esteem and friendship of Dr. Halley; who, being worn out by age and infirmities, thought he could not do better for the service of astronomy, than procure for Mr. Bradley the place of regius professor of astronomy at Greenwich, which he himself had many years possessed with the greatest reputation. With this view he wrote many letters, desiring Mr. Bradley's permission to apply for a grant of the reversion of it to him, and even offered to resign it in his favour, if it should be thought necessary: but Dr. Halley died before he could accomplish this kind object. Our author however obtained the place, by the interest of lord Macclesfield, who was afterward president of the Royal Society; and upon this appointment the university of Oxford sent him a diploma of doctor of divinity.

The appointment of astronomer royal at Greenwich, which was dated the 3d of February 1741-2, placed our author in his proper element; and he pursued his observations with unwearied diligence. However numerous the collection of astronomical instruments at that observatory, it was impossible that such an observer as Dr. Bradley should not desire to increase them, as well to answer those particular views, as in general to make observations with greater exactness. In the year 1748 therefore, he took the opportunity of the visit of the Royal Society to the observatory, annually made to examine the instruments and receive the professor's observations for the year, to represent so strongly the necessity of repairing the old instruments, and providing new ones, that the society thought proper to make application to the king, who was pleased to order 1000 pounds for that purpose. This sum was laid out under the direction of our author, who, with the assistance of the late celebrated Mr. Graham and Mr. Bird, furnished the observatory with as complete a col- | lection of astronomical instruments, as the most skilful and diligent observer could desire. Dr. Bradley, thus furnished with such assistance, pursued his observations with great assiduity during the rest of his life; an immense number of which was found after his death, in 13 folio volumes, and were presented to the university of Oxford in the year 1776, on condition of their printing and publishing them; but which however, unfortunately for the improvement of astronomy, now after a lapse of almost 20 years, has never yet been done.

During Dr. Bradley's residence at the Royal Observatory, the living of the church at Greenwich became vacant, and was offered to him: upon his refusing to accept it, from a conscientious scruple, “that the duty of a pastor was incompatible with his other studies and necessary engagements,” the king was pleased to grant him a pension of 250l. over and above the astronomer's original salary from the Board of Ordnance, “in consideration (as the sign manual, dated the 15th Feb. 1752, expresses it) of his great skill and knowledge in the several branches of astronomy and other parts of the mathematics, which have proved so useful to the trade and navigation of this kingdom.” A pension which has been regularly continued to the astronomers royal ever since.

About 1748, our author became entitled to bishop Crew's benefaction of 30l. a year, to the lecture reader in experimental philosophy at Oxford. He was elected a member of the Academy of Sciences at Berlin, in 1747; of that at Paris, in 1748; of that at Petersburgh, in 1754; and of that at Bologna, in 1757. He was married in the year 1744, but never had more than one child, a daughter.

By too close application to study and observations, Dr. Bradley became afflicted, for near two years before his death, with a grievous oppression on his spirits; which interrupted his useful labours. This distress arose chiefly from an apprehension that he should outlive his rational faculties: but this so much dreaded evil never came upon him. In June 1762 he was seized with a suppression of urine, occasioned by an inflammation in the reins, which terminated his existence the 13th of July following. His death happened at Chalfont in Gloucestershire, in the 70th year of his age; and he was interred at Minchinhampton in the same county.

As to his character, Dr. Bradley was remarkable for a placid and gentle modesty, very uncommon in persons of an active temper and robust constitution. Although he was a good speaker, and possessed the rare but happy art of expressing his ideas with the utmost precision and clearness, yet no man was a greater lover of silence, for he never spoke but when he thought it absolutely necessary. Nor was he more inclined to write than to speak, as he has published very little: he had a natural diffidence, which made him always afraid that his works might injure his character; so that he suppressed many which might have been worthy of publication.

His papers, which have been inserted in the Philos. Trans. are,

1. Observations on the comet of 1703. Vol. 33, p. 41.

2. The longitude of Lisbon and of the fort of New York from Wansted and London determined by the eclipse of the first satellite of Jupiter. Vol. 34, p. 85.

3. An account of a new discovered Motion of the Fixed Stars. Vol. 35, p. 637.

4. On the Going of Clocks with Isochronal Pendulums. Vol. 38, p. 302.

5. Observations on the Comet of 1736-7. Vol. 40, p. 111.

6. On the apparent Motion of the fixed Stars. Vol. 45, p. 1.

7. On the Occultation of Venus by the Moon, the 15th of April 1751. Vol. 46, p. 201.

8. On the Comet of 1757. Vol. 50, p. 408.

9. Directions for using the Common Micrometer. Vol. 62, p. 46.