Dr James, a famous English astronomer, was the third son of William and Jane Bradley, and was born at Sherborne in Dorsetshire in the year 1692.

He was educated for the university at North Leach by Mr Egles and Mr Brice, who kept a boarding-school there; and from North Leach he was sent to Oxford. His friends intended him for the church, and his studies were regulated with that view; and as soon as he was of sufficient age to receive holy orders, the bishop of Hereford, who had conceived a great esteem for him, gave him the living of Bridatow, and soon after he was inducted to that of Welfrie in Pembrokeshire. But notwithstanding these advantages, from which he might promise himself still farther advancement in the church, he at length resigned his livings, that he might be wholly at liberty to pursue his favourite study the mathematics, and particularly astronomy. He was nephew to Mr Pound, a gentleman who is well known in the learned world by many excellent observations, and who would have enriched it with more, if the journals of his voyages had not been burnt at Pulo Condore, 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, Mr Bradley passed all the time that he could spare from the duties of his function; and perhaps he sometimes trespassed upon them: he was then sufficiently acquainted with the mathematics to improve by Mr Pound's conversation; yet it does not appear that, in this study, he had any preceptor but his genius, or any assistant but his labour.

It may be easily imagined, that the example and conversation of Mr Pound did not render Bradley more fond of his profession than he was before; 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 afterwards distinguished him as one of the greatest astronomers of his age. Though these observations were made as it were by stealth, they gained him at first the notice, and then the friendship, of the lord chancellor Macclesfield, Mr Newton, afterwards Sir Isaac, Mr Halley, and many other members of the Royal Society, into which he was soon elected a member. About the same time, the chair of Savilian professor of astronomy became vacant by the death of the celebrated Dr Keil; and Mr Bradley was elected to succeed him on the 31st of October 1721, being then just 29 years old; and his colleague was Mr Halley, who was professor of geometry on the same foundation. Bradley, upon his being elected into this professorship, gave up both his livings, and with great joy quitted a situation in which his duty was directly opposite to his inclination. From this time, he applied himself wholly to the study of his favourite science; and in the year 1727 he published his theory of the aberration of the fixed stars, which is allowed to be one of the most useful and ingenious discoveries of modern astronomy. Three years after this discovery, by which Mr Bradley acquired very great reputation, he was appointed lecturer in astronomy and physics, at the museum of Oxford.

He pursued his studies with equal application and delight; and in the course of his observations, which were innumerable, he discovered that the inclination of the earth's axis upon the plane of the ecliptic was not always the same, but that it varied backwards and forwards some seconds, and that the period of these variations was nine years. This period seemed altogether unaccountable, as it could not be supposed to have anything in common with the revolution of the earth, which is performed in one year. Mr Bradley, however, discovered the cause of this phenomenon in the Newtonian system of attraction. He published this discovery in 1737, so that in the space of about ten years he communicated to the world two of the finest discoveries in modern astronomy, which will for ever make a memorable epocha in the history of that science. Mr Bradley always preserved the esteem and friendship of Mr Halley; who, being worn out by age and infirmities, thought he could do nothing farther for the service of astronomy, than procure for Mr Bradley the place of regius professor of astronomy at Greenwich, which he had possessed himself many years with the greatest reputation. With this view, he wrote many letters, which have been since found among Mr Bradley's papers, desiring his permission to apply for a grant of the reversion of it to him, and even offering to resign in his favour, if it should be thought necessary: but before Mr Halley could bring this kind project to bear, he died. Mr Bradley, however, obtained the place afterwards, by the favour and interest of Lord Macclesfield, who was afterwards president of the Royal Society. As soon as the appointment of Mr Bradley to this place was known, the university of Oxford sent him a diploma creating him doctor of divinity. The appointment of astronomer at Greenwich placed Mr Bradley in his proper element, and he pursued his observations with unwearied diligence. However numerous the collection of astronomical instruments at the observatory at Greenwich, 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 annual visit made by the Royal Society to the observatory, in order 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 purchasing new, that the society thought proper to represent it to his majesty, and his majesty gave them £1000, for that purpose. This sum was laid out under the direction of Dr Bradley, who, with the assistance of the late celebrated Mr Graham and Mr Bird, furnished the observatory with as complete a collection of astronomical instruments, as the most skilful and diligent observer could desire. Dr Bradley, furnished with such assistance, pursued his observations with new assiduity, an incredible number of which were found after his death, and put into the hands of the Royal Society.

It has been already observed, that when Dr Bradley was elected to the professor's chair at Oxford, he gave up his two livings, which were at such a distance, that he could not possibly fulfil the duties of them himself; but it happened that after he was settled at Greenwich the living of that parish became vacant, which is very considerable, and which was offered to him, as he was upon the spot to perform the duty, and had the claim of uncommon merit to the reward. This living, however, Dr Bradley, very greatly to his honour, refused, fearing the duties of the astronomer would too much interfere with those of the divine. His majesty, however, hearing of the refusal, was so pleased with it, that he granted him a pension of £250l. a-year, in consideration of his great abilities and knowledge in astronomy and other branches of the mathematics, which had procured so much advantage to the commerce and navigation of Great Britain, as is particularly mentioned in the grant, which is dated the 15th of February 1752. Dr Bradley, about the same time, was admitted into the council of the Royal Society. In the year 1748, he was admitted a member of the royal academy of sciences and belles lettres of Berlin, upon the death of M. Crevier, first physician to his Catholic majesty; in the year 1752, a member of the imperial academy at Petersburg; and in 1757, of that instituted at Bologna.

Dr Bradley was still indefatigable in his observations, and whatever honour he received became an incitement to obtain new distinction; his corporeal abilities, however, at length declined, though his intellectual suffered no abatement. In the year 1789, he became extremely weak and infirm; and towards the end of June 1762, he was attacked with a total suppression of urine, caused by an inflammation of the reins, which on the 12th of July following put an end to his life, in the 70th year of his age. He was buried at Mitchin Hampton, in Gloucestershire, in the same grave with his mother and his wife. In the year 1744, he married Susannah Peach, the daughter of a gentleman of that name in Gloucestershire, by whom he had only one daughter.

As to his character, he was remarkable for a placid and gentle modesty, very uncommon in persons of an active temper and robust constitution. It was still more remarkable, that, with this untroubled equanimity of temper, he was compassionate and liberal in the highest degree. Although he was a good speaker, and possessed the rare but happy art of expressing his ideas with the utmost precision and perspicuity, yet no man was a greater lover of silence, for he never spoke but when he thought it absolutely necessary. He did indeed think it necessary to speak when he had a fair opportunity to communicate any useful knowledge in his own way; and he encouraged those that attended his lectures to ask him questions, by the exactness with which he answered, and the care he took to adapt himself to every capacity. He was not more inclined to write than to speak, for he has published very little; he had a natural diffidence, which made him always afraid that his works should injure his character; and therefore suppressed many, which probably were well worthy of the public attention. He was even known, as it were, in spite of himself; and, in spite of himself, he was known much, and consequently much esteemed. He was acquainted with many of the first persons in this kingdom, persons eminent as well for their rank as their abilities; he was honoured by all men of learning in general; and there was not an astronomer of any eminence in the world with whom he had not a literary correspondence. Upon the whole, it may be said of Dr Bradley, that no man cultivated great talents with more success, or had a better claim to be ranked among the greatest astronomers of his age.