WATSON, HENRY WILLIAM (1827–1903), mathematician, born at Marylebone on 25 Feb. 1827, was son of Thomas Watson, R.N., by his wife Eleanor Mary Kingston. Educated at King's College, London, he won the first mathematical scholarship instituted there, proceeding in 1846 to Trinity College, Cambridge, where he was scholar. He graduated as second wrangler and Smith's prizeman in 1850, Dr. W. H. Besant being senior wrangler. He became fellow in 1851, and from 1851 to 1853 was assistant tutor. With James Fitzjames Stephen, who entered Trinity in 1847, Watson formed a close friendsbip (see Leslie Stephen's}} Life of Sir J. F. Stephen). Both were 'Apostles,' and (Sir) William Harcourt, (Sir) Henry Sumner Maine, and E. H. Stanley (afterwards fifteenth Earl of Derby) belonged to their coterie. After a short stay in London, studying law (with Stephen as fellow-student), Watson became mathematical master in the City of London School (1854), and was afterwards (1857) mathematical lecturer at King's College, London. Ordained deacon in 1856, he took priest's orders in 1858. From 1857 to 1865 he was a mathematical master at Harrow School, retiring on presentation to the benefice of Berkswell, near Coventry. One of the original founders of the Alpine Club in 1857, he delighted in mountaineering, but left the Club in 1862.
Watson was moderator and examiner during 1860–1 in the Cambridge mathematical tripos, and an additional examiner in 1877. From 1893 to 1896 he was examiner in mathematics at London University. One of the founders of the Birmingham Philosophical Society, he was president 1880-1. He was elected F.R.S. on 2 June 1881. Cambridge University conferred the honorary Sc.D. degree in 1883. Watson's independent publications were 'The Elements of Plane and Solid Geometry' (1871) and 'Treatise on the Kinetic Theory of Gases' (1876; 2nd edit. 1893, which embodied criticisms given in correspondence by Clerk Maxwell). In collaboration with Samuel Hawksley Burbury [q. v. Suppl. II] there appeared 'A Treatise on Generalised Co-ordinates applied to the Kinetics of a Material System' (1879), a work on abstract dynamics; and 'The Mathematical Theory of Electricity and Magnetism,' vol. i. 'Electrostatics' (1885), vol. ii. 'Magnetism and Electrodynamics' (1889). The article 'Molecule' in the 'Encyclopædia Britannica,' 9th edition, was also written jointly with Burbury.
Watson's contributions to serial scientific literature include 'Direct Investigation of Lagrange's and Monge's Methods of Solution of Partial Differential Equations,' in the 'Quarterly Journal of Mathematics' (1863); 'The Kinetic Theory of Gases' and 'On the Progress of Science, its Conditions and Limitations,' read at the Birmingham' Philosophical Society (1877, 1891); and, jointly with Sir Francis Galton [q. v. Suppl. II], 'On the Probability of the Extinction of Families' (Journ. Anthrop. Inst. vol. iv.).
He died at Brighton on 11 Jan. 1903, five months after his resignation of Berkswell. He married in 1856 Emily, daughter of Henry Rowe, of Cambridge; his wife's sister married Robert Baldwin Hayward [q. v. Suppl. II]. He had issue one son and two daughters.
[Proc. Roy. Soc. vol. lxxv.; Roy. Soc. Catal. Sci. Papers; Nature, 22 Jan. 1903; Men of the Time, 1899; The Times, 13 Jan. 1903.]
WATSON, JOHN, who wrote under the pseudonym of Ian Maclaren (1850–1907), presbyterian divine and author, born at Manningtree, Essex, on 3 Nov. 1850, was only child of John Watson (d. 1 Jan. 1879), a clerk in the civil service, who subsequently became receiver-general of taxes in Scotland, by his wife Isabella Maclaren. He came of pure Highland stock. His father was born at Braemar, while his mother belonged to the Loch Tay district and spoke Gaelic. Her ancestors were Roman catholics. Watson's parents, however, belonged to the Free Church of Scotland.
When Watson was about four the family removed to Perth. After attending the grammar school of that city, he was sent to the high school of Stirling, where his companions included Henry Drummond [q. v. Suppl. I]. In 1866 he entered Edinburgh University. His career there was somewhat disappointing, but he showed some promise in philosophy and became president of the University Philosophical Society. He graduated M.A. in 1870.
Reluctantly, at his father's wish, he studied for the ministry of the Free Church of Scotland at New College, Edinburgh (1870-4); his teachers included Andrew Bruce Davidson [q. v. Suppl. II] and Robert Rainy [q. v. Suppl. II]. His course was undistinguished; at its close he passed a
