Brinkley, John

(1766/7-1835), mathematician and astronomer

by P. A. Wayman

© Oxford University Press 2004 All rights reserved

Brinkley, John (1766/7-1835), mathematician and astronomer, was born, probably in December 1766 but possibly in January 1767, in Woodbridge, Suffolk, and was baptized there on 31 January 1767. His father was John Toler, a vintner, and his maternal grandfather was John Brinkley, a butcher. His mother, Sarah Brinkley, married a James Boulter in 1770. He graduated as senior wrangler and Smith's prizeman at Gonville and Caius College, Cambridge, in 1788 and was a fellow of Caius from 1788 to 1790. It appears that his fees at Cambridge were paid by a donor, who may have been his last tutor, the Revd Tilney of Harleston, Northamptonshire, who recognized his scholarly talents and prepared him for entry to Cambridge. He was ordained deacon in Ely Cathedral in 1790 and priest in Lincoln Cathedral in 1791. Probably in 1792 he married Esther Weld, the daughter of Matthew Weld of Dublin. They had two sons, John and Matthew, and fifteen grandchildren are recorded; one son was ordained in the Church of Ireland and the other was for a time a vicar choral.

Brinkley was, during 1787 and 1788, an assistant to the astronomer royal, Nevil Maskelyne, at Greenwich. At the age of twenty-four he was appointed as Andrews' professor in succession to the first holder, Revd Henry Ussher (d. 1790), who had survived only five years in post. Ussher had planned the building and instrumental equipment of the Dunsink observatory in 1783-5 in collaboration with Maskelyne, and, after consultation with Maskelyne, the board of Trinity College, Dublin, chose Brinkley in preference to existing fellows of the college who sought to obtain the appointment--but only after the provost, John Hely Hutchinson, had exercised his veto. Realizing that strong measures were necessary, Hutchinson not only consulted Maskelyne as to the best person he could recommend, but succeeded within a few years in having the Andrews' professor recognized as royal astronomer of Ireland by letters patent of George III in 1792.

It was intended that the Andrews' professor should convey to his students the achievement of 'natural philosophy' in reducing the elaborate representation of planetary motions of the Ptolemaic system to a system described by a few simple equations of motion and an equation for the force of gravity. Brinkley, as the first royal astronomer of Ireland, fulfilled the role by being a distinguished scientist as well as an inspiring teacher. It is likely that his Elements of Plane Astronomy of 1808 was the first English-language textbook for teaching astronomy in universities; in Dublin it went through several revisions up to the end of the nineteenth century as a standard Trinity College text.

Brinkley's work in astronomy was in mathematical methods, including a pioneering application of Gauss's method of least squares to reduction of observational data. He derived new values for fundamental astronomical quantities, including aberration, nutation, and precession, published in 1819, and it was for the first theory of the motion of lunar perigee, published in 1818, that he was awarded the Cunningham medal of the Royal Irish Academy in 1817. He had also produced, in 1814, a definitive account of refraction by the earth's atmosphere.

Delivery of Jesse Ramsden's long-awaited 8 foot vertical circle, completed after his death by his successor Matthew Berge, was finally made in 1808. Brinkley thereupon set out on what he intended to be his life's work--the determination of the parallax of a star, or the direct observation of the distance to one or more of the nearest stars. He concentrated his work on some fifteen bright stars, and in due course he settled on four, alpha Cygni, alpha Lyrae, alpha Bootis, and alpha Aquilae, as having shown a parallax of near to 1 arc-second (in the case of the first three) and of 2.7 arc-seconds (in the case of alpha Aquilae). Throughout the course of this work, and at its conclusion, John Pond at Greenwich steadfastly maintained that the observed parallaxes were spurious, basing his ultimate opinion on results from instruments fixed to a meridian 'wall', each one to observe just one star round the year, as far as possible. This was one of the most celebrated controversies in observational astronomy of that time and it was concluded by a verdict clearly against Brinkley, in spite of the care with which he had reduced his observations. The cause of Brinkley's failure has been recognized to lie in his instrument, which was not suited to the task in that it was larger than other similar circles and had no special refinement in its adjustments. In fact these stars are far too distant to show parallax. However, Brinkley is generally credited with having paid great attention to the methods used in deriving parallax from observations, and the later success of others benefited from his jeopardized attempts.

Finding his salary as a professor of astronomy inadequate for his needs, Brinkley sought and obtained preferment in the Church of Ireland to the extent that he became a recognized authority on ecclesiastical law. After holding several sinecures he was appointed bishop of Cloyne, in co. Cork, in 1826, an unusual attainment for a man born out of wedlock.

Brinkley was made a fellow of the Royal Society of London in 1803 and received its Copley medal in 1824. He was president of the Royal Irish Academy from 1822 to 1835 and of the Astronomical Society of London from 1831 to 1833, which office he held at the time of the granting of the royal charter in 1831, when it became the Royal Astronomical Society. Brinkley had a gentle and peaceable character and his reluctant dispute with Pond was carried through without rancour. His humble origin was, for its time, unusual for a man of his eminence. He died at Leeson Street, Dublin, on 14 September 1835, and was buried in Trinity College chapel.

P. A. WAYMAN

Sources  
Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London, 3 (1830-37), 354
Monthly Notices of the Astronomical Society of London, 3 (1833-6), 148
R. S. Ball, Great astronomers (1895)
Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences, 1 (1835), 212
DNB
S. M. P. McKenna, 'Brinkley, John', DSB
'Report of the council of the society to the sixteenth annual general meeting, February 12 1836', Memoirs of the Royal Astronomical Society, 9 (1836), 281
P. A. Wayman, Dunsink observatory, 1785-1985: a bicentennial history (1987)
W. M. Brady, Clerical and parochial records of Cork, Cloyne, and Ross, 3 (1864), 130
J. B. Leslie, Clogher clergy and parishes (1929), 47
Venn, Alum. Cant.
private information (2004)

Archives  
Denbighshire RO, Ruthin, family and other corresp.
Dunsink observatory, Dublin
TCD, corresp. and papers |  Hunt. L., letters to Sir Francis Beaufort
RS, corresp. with Sir William Herschel

Likenesses  
M. Cregan, oils, c.1827
J. Hogan, relief on marble monument, TCD
effigy on memorial tablet, TCD
oils, Gon. & Caius Cam.
portrait (as president of Royal Irish Academy), Royal Irish Acad.


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