In the year 1730, Mr Bradley was appointed to suc ceed Mr Whiteside as lecturer in astronomy and expe rimental philosophy in the university ol Oxford, an office which he held during the remainder of his life; and in 1737 he published his observations on the co met which appeared at the beginning of that year. From the situation which our author held at Oxford, he was intimately acquainted with Dr Halley, who soon perceived and appreciated the excellence of his character, and the extent of his attainments. Worn out with the labours of study, and sensible that his health was rapidly declining, this veteran philosopher was solicitous that Dr Bradley should succeed him as astronomer royal at Greenwich, —a situation for which he was, above all others, so eminently qualified. He accordingly made fre quent applications for the reversion of this office to his young friend, and even offered to resign it in his favour, if such a step were necessary to his success. Death, however, put an end to the friendly solicita tions of this venerable man, before they had been crowned with success; but through the influence of the Earl of Macclesfield, the president of the Royal Society, Bradley was appointed to the office of astro nomer royal in 174.2 ; an appointment which the uni versity of Oxford very properly distinguished, by conferring upon Bradley the degree of doctor in di vinity.
In the year 1744•, Dr Bradley married Mrs Susan nah Peach, the daughter of Samuel Peach, Esq. of Chalford in Gloucestershire. The result of this mar riage was only one daughter, who survived her father.
In the course of his observations on the declina tions of the fixed stars, Dr Bradley was led, in 1745, to the discovery of the nutation of the earth's axis, of which he communicated a detailed account to the Royal Society, in 174.7, in a letter addressed to the Earl of Macclesfield. In this admirable letter, which is equally remarkable for its philosophical precision, and for the simplicity and modesty with which it is writ ten, Dr. Bradley takes an opportunity of expressing the obligations which he lay under to Mr. George Graham, by whom his instruments were principally made ; and we cannot help contrasting his conduct, in this respect, with that ol many modern mathemati cians, who arc too apt to overlook the high claim to reputation, which the makers of philosophical instru ments most undoubtedly possess. " I am sensible," says Dr Bradley, "that if my own endeavours have, in any respect, been eactual to the advancement of astronomy, it has principally been owing to the ad vice and assistance given me by Mr George Graham, whose great skill and judgment in mechanics, joined with a complete and practical knowledge of the uses of astronomical instruments, enable him to contrive and execute them in the most perfect manner."
The important discovery of the nutation of the earth's axis was rewarded with the gold medal, which was annually given by the Society.
From the numerous observations which Dr Brad ley had now made, he became more and more sensible of the necessity of having instruments even more accu rate than those which he had used ; for, to use his own words, "as we advance in the means of making more nice enquiries, new points generally offer themselves, that demand our attention." Ile therefore embraced the opportunity presented by the annual visit which the Royal Society made to the observatory, and he pointed out to the learned deputation from that body, the necessity both of repairing the (aid instruments, and of obtaining several new ones. In consequence of this representation, the Society obtained from George II. in 1748, a grant of 10001., to be expend ed on astronomical apparatus, under his superinten dence. With the assistance of Mr George Graham and Mr John Bird, the observatory was soun furnish ed with those admirable instruments, by which all his subsequent observations were made.
In the year 1751, when the living of Greenwich became vacant, Mr Pelham offered it, in the king's name, to Dr Bradley, as a token of respect for his important services to science. The same conscienti ous motives, however, which induced him to resign his livings in the church, prompted him, on the pre sent occasion, to decline an offer, which would have set at variance the duties which he owed to religion and science. The king was so much pleased with the disinterestedness of our author, that he granted him a pension of 2501. during pleasure, which was continued till the end of his reign, and renewed on the accession of his present majesty.
In 1752, Dr Bradley was admitted into the Coun cil of the Royal Society ; and in 1757, he published his observations on the comet of that year. The re mainder of our author's life was not distinguished by any events which are worthy of being recorded. He continued to prosecute his observations, with a dili gence too great for his constitution, till he was af flicted with a lowness of spirits of the most distress ing kind ; he was in constant terror of mental de rangement, and though the vigour of his faculties suffered no abatement, yet the fear of losing them altogether never ceased to haunt him till the end of his life. In 1760, his bodily strength began to expe rience a decline, and in consequence of an inflamma tion of his kidneys, he was attacked with a total sup pression of urine, which terminated his existence, at Chulford, in Gloucestershire, on the 13th of July, 1762, in the 70th year of his age. His remains were depo sited at Mitchim Hampton, in Gloucestershire, in the same grave with his wife and mother.