# Dictionary of National Biography, 1885-1900/Davies, Thomas Stephens

**DAVIES**, THOMAS STEPHENS (1795–1851), mathematician and writer on science, made his earliest communications to the ‘Leeds Correspondent’ in July 1817, and the ‘Gentleman's Diary’ for 1819, and he subsequently contributed largely to the ‘Gentleman's and Lady's Diary, to Clay's ‘Scientific Receptacle,’ to the ‘Monthly Magazine,’ the ‘Philosophical Magazine,’ the ‘Bath and Bristol Magazine,’ and the ‘Mechanics' Magazine.’ His early acquaintance with Dr. William Trail, the author of the ‘Life of Dr. Robert Simson,’ materially influenced his course of study, and made him familiar with the old as well as with the modern professors of geometry. He became a fellow of the Royal Society of Edinburgh in 1831, and he contributed several original and elaborate papers to its ‘Transactions.’ He also published ‘Researches on Terrestrial Magnetism’ in the ‘Philosophical Transactions,’ ‘Determination of the Law of Resistance to a Projectile’ in the ‘Mechanics' Magazine,’ and other papers in the ‘Cambridge and Dublin Mathematical Journal,’ the ‘Civil Engineer,’ the ‘Athenæum,’ the ‘Westminster Review,’ and ‘Notes and Queries.’ He was elected a fellow of the Society of Antiquaries 19 March 1840. In 1834 he was appointed one of the mathematical masters in the Royal Military Academy at Woolwich. Among the very numerous subjects which engaged his attention were researches on the properties of the trapezium, Pascal's hexagramme mystique, Brianchon's theorem, symmetrical properties of plane triangles, and researches into the geometry of three dimensions. His new system of spherical geometry preserves his name in the list of well-known mathematicians. His death, after six years of illness, took place at Broomhall Cottage, Shooter's Hill, Kent, on 6 Jan. 1851, when he was in his fifty-seventh year.

Davies edited the following works: 1. ‘A Course of Mathematics for the use of the Royal Military Academy, by Charles Hutton. The eleventh edition by Olinthus Gregory,’ 1837, 2 vols.; the principal alterations, additions, and improvements in this work were made by Davies. 2. ‘Solutions of the Principal Questions in Dr. Hutton's “Course of Mathematics,”’ 1840. 3. ‘A Course of Mathematics, by C. Hutton, continued by O. Gregory; twelfth edition by T. S. Davies,’ 1841–3, 2 vols. 4. ‘The Mathematician,’ ed. by T. S. Davies and others, 1845, 1847, and 1850. Of the above, No. 2, ‘Solutions of the Principal Questions,’ is the most important work. It is a large octavo of 560 pages, enriched with four thousand solutions on nearly all subjects of mathematical interest and of various degrees of difficulty. A long catalogue of Davies's writings is printed in the ‘Westminster Review,’ April 1851, pp. 70–83.

[Gent. Mag. May 1851, p. 559; Illustrated London News, xviii. 38 (1851); Mechanics' Mag. 11 Jan. 1851, pp. 33–5; The Expositor, an Illustrated Recorder (London, 1851), i. 284, with portrait.]