Brouncker, William

, viscount Brouncker, of Castle Lyons in Ireland, son of sir William Brouncker, afterwards made viscount in 1645, was born about 1620; and, having received an excellent education, discovered an early genius for mathematics, in which he afterwards became very eminent. He was created M. D. at Oxford, June 23, 1646. In 1657 and 1658, he was engaged in a correspondence on mathematical subjects with Dr. John Wallis, who published the letters in his “Commercium. Epistoiicum,” Oxford, 1658, 4to. He, with others of the nobility and gentry who had adhered to king Charles I. in and about London, signed the remarkable declaration published in April 1660. After the restoration, he was made chancellor to the queen consort, and a commissioner of the navy. He was one of those great men who first formed the royal society, and, by the charter of July 15, 1662, and that of April 22, 1663, was appointed the first president of it: which office he held with great advantage to the society, and honour to himself, till the anniversary election, Nov. 30, 1677. Besides the offices mentioned already, he was master of St. Ratherine’s near the Tower of London; his right to which post, after a long contest between him and sir Robert &tkyns, one of the judges, was determined in his favour, Nov. 1681. He died at his house in St. James’s street, Westminster, April 5, 1684; and was succeeded in his honours by his younger brother Harry, who died Jan. 1687. Of his works, notwithstanding his activity in promoting literature and science, there are few extant. These are: “Experiments on the recoiling of Guns,” published in Dr. Sprat’s History of the Royal Society; “An algebraical paper upon the squaring of the Hyperbola,” published in the Philosophical Transactions. (See Lowthorp’s Abr. vol. I. p. 10, &c.); “Several Letters to Dr. James Usher, archbishop of Armagh,” annexed to that primate’s life by Dr. Parr; and “A translation of the Treatise of Des Cartes, entitled Musicae Compendium,” published without his name, but enriched with a variety of observations, which shew that he was deeply skilled in the theory of the science of music. Although he agrees with his author almost throughout the book, he asserts that the geometrical is to be preferred to the arithmetical division; and with a view, as it is presumed, to the farther improvement of the “Systema | Participato,” he proposes a division of the diapason by sixteen mean proportionals into seventeen equal semitones; the method of which division is exhibited by him in an algebraic process, and also in logarithms. The “Systema Participato,” which is mentioned by Bontempi, consisted in the division of the diapason, or octave, into twelve equal semitones, by eleven mean proportionals. Descartes, we are informed, rejected this division for reasons which are far from being satisfactory. Mr. Park, in his edition of lord Orford’s “Royal and Noble Authors,” to which we are frequently indebted, points out an original commission, among the Sloanian Mss. from Charles II. dated Whitehall, Dec. 15, 1674, appointing lord Brouncker and others to inquire into, and to report their opinions of a method of finding the longitude, devised by Sieur de St. Pierre. ¹