James Bradley

"Bradley, aided by only one assistant, continued with indefatigable assiduity to prosecute his labours at the Royal Observatory, until at length, in the autumn of 1761, he was compelled by the increasing frailties of old age, to retire from the duties of active life. ...he shortly afterwards withdrew to Chalford, in Gloucestershire, where he continued to reside among his wife's relations till his death, which took place on the 13th of July, 1762, having attained the age of 70 years."

"In 1751 a pension was granted to Bradley by George ll., not as an augmentation of salary, but as a gratuitous acknowledgment of his personal merit."

"The registers of Bradley's observations occupied thirteen folio volumes, and at his death were taken possession of by his executors. In 1767 the Government, under the impression of their being public property, commenced a law-suit with a view to their recovery, which, however, they abandoned in 1776. As soon as it was ascertained that the Government had relinquished their claim, the manuscripts were transmitted to Lord North, who was then Chancellor of the University of Oxford, to be presented by him to the University. They were finally printed, at the expense of the University, in two folio volumes. The first volume was published in 1798, under the superintendence of Dr. Hornsby. The second volume was prepared for the press by Dr. Robertson, and appeared in 1805. These two volumes contain the observations made by Bradley, from 1750 to 1762. The original manuscripts, as well as the registers of the observations made by Bradley, at Greenwich, previous to 1750, are deposited in the , Oxford."

"The vast mass of observations made by Bradley... two volumes... continued inapplicable to any useful purpose, in consequence of their not being reduced, until... Bessel undertook to execute this task... The results of his labours were published in 1818, at Königsberg, in one folio volume, entitled Fundamenta Astronomiæ pro anno 1755, deducta ea Observationibus viri incomparabilis James Bradley, in specula Astronomica Grenovicensi per annos 1750 1762 institutis. In this work Bessel has determined, by a series of elaborate investigations, the quantity and laws of refraction, the maximum value of aberration, and other fundamental points of astronomy, as deducible from Bradley s observations."

"The observations made with the zenith sector at Kew and Wanstead, by the intercomparison of which Bradley was conducted to the discovery of aberration, were at one time supposed to be lost; but having been found among the papers of the late Dr. Hornsby, they were published by Professor Rigaud, in 1832, at the expense of the University, of which the immortal author of the discovery forms one of the brightest ornaments."

"laid the foundation of his career at Greenwich where he worked from 1756 to 1760 as assistant observer to the Reverend James Bradley, Astronomer Royal. Bradley was then near the end of his career... As a young man he had discovered the aberration of light and the nutation of the axis of the Earth and had founded a new era of precise observations. He had enlarged the Greenwich Observatory and equipped it with new instruments. Mason acquired some of the spirit and the ideals of his preceptor and learned from him the use of instruments of precision and the art of observing. At Greenwich Mason made the acquaintance of the Reverend , a young astronomer who was assisting the Astronomer Royal in a study of atmospheric refraction. This association of Mason and Maskelyne continued as long as Mason lived."

"And at Greenwich Mason first learned to know Mayer's Tables of the Moon. ...Bradley first reported on Mayer's Tables on February 10, 1756, and finally on April 14, 1760. With the assistance of Charles Mason, Bradley had compared positions of the Moon as predicted in the Tables with positions as observed at Greenwich. Eleven hundred comparisons led to the comment: So far as it will depend upon the lunar tables the true longitude of a ship at sea may in all cases be found within about half a degree and generally much nearer. It remained to be examined within what limits the errors arising from observations actually taken at sea could be contained. This test was carried out for Bradley by Captain Campbell, of H.M.S. Royal George, on cruises near Ushant in 1758 and 1759. A sextant was made especially for the trials by John Bird, instrument maker for Greenwich Observatory. Bradley's final comment reads: However great the difficulties of finding the longitude by this method seem to be, they are not insuperable, or such as ought to deter those whom it most nearly concerns from attempting to remove them. James Bradley was now nearing the end of his days. His hand was faltering. Nevil Maskelyne and Charles Mason received the torch he had carried. They made the development of the method of lunar distances for finding the longitude at sea a major concern of the rest of their lives."

"James Bradley's successor as Astronomer Royal was , who lived only two years after his appointment. Maskelyne succeeded him early in 1765 and thus became the fifth Astronomer Royal at Greenwich."

"The last quarter of 's life was spent on projects that grew out of his earlier work at Greenwich Observatory as assistant observer to Astronomer Royal Bradley. From studies of Bradley's records Mason prepared tables for and he was able to improve Mayer's Tables of the Moon by comparing them with the Greenwich records. was established by in 1767, immediately after his appointment as Astronomer Royal, and it has appeared annually ever since. In the first issue the latitude and longitude of are given as found by Mason and Dixon in 1761. The comment follows that "it is probable that the Situation of few Places is better determined." To the Almanac for 1773 Mason contributed a catalogue of stars. The preface, written by Maskelyne, states: To this are annexed... a Catalogue of 387 fixed Stars.... adapted to the beginning of the year 1760... calculated from the late Dr. Bradley's Observations by Mr. Charles Mason, formerly his Assistant. ...After the Catalogue follow some Memoranda... communicated by the same Mr. Mason."

"The issue [of the Nautical Almanac] for 1774 first introduces Mason's improvements of Mayer's Lunar Tables. The preface written by Maskelyne on July 2, 1772, states: To this Ephemeris are annexed 1220 Longitudes and Latitudes of the Moon deduced from the late Dr. Bradley's Observations. ...The greater part of these calculations were made during Dr. Bradley's Lifetime by himself and his Assistant Mr. Charles Mason; and what was left unfinished has been completed by Mr. Mason since, at the Instance and at the Expense of the Board of Longitude. A Series of Observations this for Number and Exactness far excelling anything of the kind which the World ever saw before... Accordingly the Board of Longitude have thought proper to employ Mr. Mason farther in making the necessary calculations for improving Mayer's printed Tables under my Direction..."

"James Bradley had not published his Greenwich observations. In law they proved to be his personal property, and after his death they were claimed successfully by his only child, a daughter, and her husband, the Reverend Samuel Peach. They in turn gave the records to Oxford University where Bradley had studied and had held the Savilian professorship of Astronomy. The first of Bradley's records to be published was the catalogue of stars that Mason prepared for the Nautical Almanac of 1773. The Clarendon Press of Oxford University undertook the publication of all the records. The first volume appeared in 1798 under the editorship of Professor . It includes Mason's star catalogue. Mason and Hornsby carried on an extensive correspondence about the Greenwich records that undoubtedly aided in preparing them for the press. The second volume, edited by Dr. Abram Robertson, appeared in 1805. Finally in 1832 there was published The Miscellaneous Works and Correspondence of Reverend James Bradley under the editorship of Professor S. P. Rigaud."