'L'Européen' (Paris, 15 March 1902) on 'La Vieille Littérature Irlandaise,' have not been reprinted.
[Personal memories; private sources; Mr. W. B. Yeats's Collected Works, viii. 173; Contemp. Rev., April 1911, p. 470; art. by Mr. Jack B. Yeats in New York Sun, July 1909; Manchester Guardian, 25 March 1909; J. M. Synge: a Critical Study, by P. P. Howe, 1912; notes kindly supplied from M. Maurice Bourgeois's forthcoming study of the man and his writings; information from Mr. J. L. Hammond.]
TAIT, PETER GUTHRIE (1831–1901), mathematician and physicist, born on 28 April 1831 at Dalkeith, was only son in a family of three children of John Tait, secretary to Walter Francis Scott, fifth duke of Buccleuch [q. v.], by his wife Mary Ronaldson. John Ronaldson, an uncle, who was a banker at Edinburgh and an amateur student of astronomy, geology, and the recently invented photography, first interested Peter in science. At six his father died, and he removed with his mother to Edinburgh. From the grammar school of Dalkeith he passed to a private school (now defunct) in Circus Place, and thence at ten (in 1841) to Edinburgh Academy. Lewis Campbell [q. v. Suppl. II] and James Clerk Maxwell [q. v.] were his seniors there by a year. Fleeming Jenkin [q. v.] was one of his own contemporaries. During his first four years he showed promise in classics, of which he retained a good knowledge through life. But his mathematical bent soon declared itself. He was 'dux' of his class in each of his six years at the academy (1841-7). At sixteen, in 1847, he entered Edinburgh University, and joined the senior classes in mathematics and natural philosophy. Next year he left Edinburgh for Peterhouse, Cambridge, where William Hopkins [q. v.] coached him for the mathematical tripos. In January 1852 he graduated B.A. as senior wrangler—the youngest on record. He was also first Smith's prizeman. A friend and fellow countrymnan of his, William John Steele, also of Peterhouse, was second wrangler. The only previous Scottish senior wrangler was Archibald Smith [q. v.] of Jordanhill in 1836. In Edinburgh Tait's success evoked boundless enthusiasm. Obtaining a fellowship at Peterhouse immediately afterwards, he began 'coaching,' and at the same time with his friend Steele commenced a treatise on 'Dynamics of a Particle.' Steele died before the book had progressed far, and it was completed by Tait, who chivalrously published it in 1856 as the joint work of 'Tait and Steele' (MS. presented by Mrs. Tait, in Peterhouse library). A second and improved edition appeared in 1865, and a seventh edition, with further revision, in 1900. The book, which still holds its own, helped to re-establish Newton's proper position in the science of dynamics, from which the brilliant work of the French mathematicians half a century earlier had apparently displaced him.
Meanwhile Tait had removed to Belfast (September 1854) to become professor of mathematics in Queen's College. Here he remained six years, and made lasting and important friendships. These friends included his fellow professor, Thomas Andrews [q. v. Suppl. I], (Sir) Wyville Thomson, James Thomson (Lord Kelvin's brother), James McCosh (afterwards president of Princeton, U.S.A.) and above all Sir William Rowan Hamilton [q. v.], the inventor of quaternions. Tait had been fascinated by Hamilton's work on 'Quaternions' while he was an undergraduate, and he soon, to the delight of Hamilton, made great and fundamental additions to the theory, subsequently producing an 'Elementary Treatise on Quaternions' (1867; 2nd edit. 1873; 3rd edit. 1890). Still later he joined with Philip Kelland [q. v.] in a more formal 'Introduction ' (1873; 2nd edit. 1881; 3rd edit. 1904). To the end of his fife Tait returned, when he could find the leisure, to this early study. With his colleague Andrews, Tait meanwhile made researches on the density of ozone and the action of the electric discharge on oxygen and other gases, and published the results in several papers. At Belfast he married on 13 Oct. 1857 Margaret Archer, daughter of the Rev. James Porter. Two of her brothers were among Tait's friends at Peterhouse, and one of these, James, was master from 1876 to 1901.
In 1860 Tait was elected professor of natural philosophy at Edinburgh in suc-