(b. Woodbridge, England, 1763; d. Dublin, Ireland, 14 September 1835)
Brinkley, whose greatest contribution was his researches into stellar parallaxes, received his early education at Woodbridge Grammar School and with a Mr. Tilney of Harleston. He went on to Caius College, Cambridge, and received his B.A. as senior wrangler and first Smith’s Prizeman in 1788. During his senior year he was assistant to N. Maskelyne at Greenwich and was fellow of his college from 1788 to 1792. Upon Maskelyne’s personal recommendation he was appointed Andrews professor of astronomy at Dublin University, 11 December 1790. The following year Brinkley was ordained a priest at Lincoln and received his M.A. at Cambridge. In 1792 he was incorporated at Dublin and elected first astronomer royal for Ireland. He proceeded D.D. (Dublin) 1806. Between 1790 and 1808 he prepared the excellent textbook Elements of Plane Astronomy, published in 1808, and ten mathematical papers, some with direct application to celestial astronomy.
Upon acquiring a splendid eight-foot meridian circle in 1808, Brinkley attempted to determine the long-sought parallax of the fixed stars, with a view to determining their distances. Two years later he announced the detection of an annual (double) parallax for a Lyrae of 2″.52, and in 1814 similarly large values of 2″.0, 5″.5, 2″.2, and 2″.1 for the stars α Lyrae, α Aquilae, Arcturus, and α Cygni, respectively. The validity of these measurements was disputed in the literature for fourteen years by Pond, who was unable to deduce analogous results with Greenwich instruments. This controversy, by necessitating repeated tests of the observations, was of great value in stimulating the study of previously unappreciated factors affecting the measurements. Brinkley’s results, although now themselves discredited, thus led to the later successful detection of stellar parallaxes.
Among Brinkley’s other major work was the publication of a new theory of astronomical refractions (1815), estimation of the obliquity of the ecliptic (1819), determination of north polar distances of the principal fixed stars (1815, 1824), and determination of the precession of the equinoxes (1828). He also used the south polar distances of certain fixed stars observed by Sir Thomas Brisbane at Paramatta, New South Wales, to investigate the accuracy of separate determinations by himself and by Bessel of their north polar distances (1826). His astronomical career ended with his elevation, after numerous ecclesiastical preferments, as bishop of Cloyne, 28 September 1826.
Brinkley’s honors were many. Fellowship of the Royal Society (1803) was followed by the Conyngham Medal of the Royal Irish Academy, for his essay on investigations relating to the mean motion of the lunar perigee (1817). He was also awarded the Copley Medal of the Royal Society (1824) for his scientific achievements and his approximations to the solution of the parallax problem. He was president of the Royal Irish Academy from 1822 to 1835, vice-president of the Astronomical Society from 1825 to 1827, and its president from 1831 to 1833.
I. Original Works. Brinkley’s various observations at Greenwich (1787–1788) are distributed through Maskelyne’s Astronomical Observations Made at the Royal Observatory, Greenwich, 3 (1799), starting with an entry for 23 Sept. 1787. Maskelyne appends the letters JB to Brinkley’s observations; those by Brinkley’s contemporary John Bumpstead appear under Bumpstead’s full name.
His elementary astronomical textbook was compiled from lectures given between 1799 and 1808 to undergraduates at Dublin University. The earliest record of the course is Synopsis of Astronomical Lectures to Commence October 29, 1799 at Philosophical School, Trinity College, Dublin (Dublin, 1799). The finished book, Elements of Plane Astronomy (Dublin, 1808), was prepared at the request of the board of the college when the acquisition of a meridian circle diverted Brinkley’s efforts to practical astronomy. The book went through five editions subject to his revision during his lifetime; a sixth edition was edited and revised by Thomas Luby (Dublin, 1845), and two further editions were revised and partly rewritten by J. W. Stubbs and F. Brünnow (LOndon, 1874, 1886).
Ten mathematical papers of considerable elegance were published between 1800 and 1818, nine in the Transactions of the Royal Irish Academy (see its Index) and one in Philosophical Transactions of the Royal Society, 97 (1807), 114–132.
Eighteen significant astronomical papers on various subjects appeared between 1810 and 1828, eight in Transactions of the Royal Irish Academy, eight in Philosophical Transactions of the Royal Society, and two in Memoirs of the Astronomical Society (see Royal Society’s Catalogue of Scientific Papers, I , 627–629). Those relating to the parallax question include the following: Brinkley’s original announcement of his detection of the annual (double) parallax of α Lyrae, communicated to the Royal Society by Maskelyne, in Philosophical Transactions, 100 (1810), 204. The 1814 report of similar and even larger results for other stars, in Transactions of the Royal Irish Academy, 12 (1815), 33–75. Discordance with Pond’s results suggested to be due to uncertainty of elements used in reduction of Greenwich observations, in Philosophical Transactions, 108 (1818), 275–302. Results of further observations introducing a determination of the constant of aberration and of that of lunar nutation, ibid., 109 (1819), 241–248, and 111 (1821), 327–360. An instrumental investigation of the effect of solar nutation cited to exhibit the competence of his equipment to detect the larger quantity of parallax, first reported to the Royal Irish Academy in 1822, in Transactions of the Royal Irish Academy, 14 (1825), 3–37. Disengagement from Greenwich results of a parallax for α Lyrae not differing sensibly from that measured at Dublin, in Memoirs of the Royal Astronomical Society, 1 , pt. 2 (1822), 329–340. Reassertion of parallax of α Lyrae and attempt to form a correct estimate of the absolute and relative degrees of accuracy of the Dublin and Greenwich instruments, in Philosophical Transactions, 114 (1824), 471–498.
Among the ten remaining catalogued papers, see Transactions of the Royal Irish Academy, 13 (1818), 25–51, containing an essay on investigations relative to the mean motion of the lunar perigee, which was awarded the Conyngham Medal of the Academy; and Memoirs of the Astronomical Society, 2 , pt. 1 (1826), 105–123, containing Brisbane’s Paramatta observations. There are several minor references in the Quarterly Journal of Science, Literature and the Arts, 9 (1820), 164–167; 11 (1821), 364–370, 370–372; and 12 (1822), 151–154; and in Astronomische Nachrichten, 3 (1825), cols. 105–106; 4 (1826), cols. 101–104; and 5 (1827), cols. 131–138.
II. Secondary Literature. An excellent discussion of Brinkley’s life and work is contained in Dictionary of National Biography, VI (1886); a more general account is in Sir Robert Ball, Great Astronomers (London, 1895), pp. 233–246. A synopsis of the contents of his Royal Society papers is in Proceedings of the Royal Society, 3 (1835), 354–355. An account of the oration by Sir Humphry Davy upon the award to Brinkley of the Copley Medal may be found in Philosophical Magazine, 64 (1824), 459–462.
Obituaries are Henry Cotton, Fasti ecclesiae Hibernicae, I (Dublin, 1851), 307–309; Gentlemen’s Magazine, 11 (1835), 547; Rev. J. B. Leslie, Clogher Clergy and Parishes (Enniskillen, 1929), p. 47; and Memoirs of the Royal Astronomical Society, 9 (1836), 281–282.
Susan M. P. McKenna