Dictionary of National Biography, 1885-1900/Ritchie, William (1790-1837)
RITCHIE, WILLIAM (1790–1837), physicist, was born about 1790. Educated for the church of Scotland, he was licensed to preach; but, abandoning the church for the teaching profession, he became rector of the Royal Academy of Tain, Ross-shire. After saving a little money, he provided a substitute to perform his duties and went to Paris, where he attended the lectures of Thénard, Gay-Lussac, and Biot. He soon acquired great skill in devising and performing experiments in natural philosophy. He became known to Sir John Herschel, and through him he communicated to the Royal Society papers ‘On a New Photometer,’ ‘On a New Form of the Differential Thermometer,’ and ‘On the Permeability of Transparent Screens of Extreme Tenuity by Radiant Heat.’ These led to his appointment to the professorship of natural philosophy at the Royal Institution, where he delivered a course of probationary lectures in 1829. In 1832 he was appointed professor of natural philosophy in the London University. Shortly afterwards he published two small treatises on geometry (1833; 3rd edit. 1853) and the differential and integral calculus (1836; 2nd edit. 1847). He communicated to the Royal Society—of which he was elected a fellow—papers ‘On the Elasticity of Threads of Glass and the Application of this Property to Torsion Balances,’ and also various experimental researches on the electric and chemical theories of galvanism, on electromagnetism, and voltaic electricity. His memoirs were more remarkable for the practical ingenuity shown in the contrivance and execution of the experiments than for theoretical value. Ritchie was subsequently engaged on experiments on the manufacture of glass for optical purposes, and a commission was appointed by the government to inquire into his results. A telescope of eight inches aperture was constructed by Dollond from Ritchie's glass, at the recommendation of the commission, but its performance was not so satisfactory as to sanction further expenditure on the experiments. He died on 15 Sept. 1837 of a fever caught in Scotland. Though the traces of an imperfect education are too manifest in his theoretical researches, he was an experimenter of great ingenuity and merit. He was ‘a man of clear head, apt at illustration, and fond of elements.’ Abstracts of his papers read before the Royal Society will be found in the ‘Philosophical Magazine’ and ‘Annals’ (new ser.) (vi. 52, viii. 58, x. 226, xi. 448) and ‘London and Edinburgh Philosophical Magazine’ (iii. 37, 145, x. 220, xi. 192). Papers contributed to the ‘Philosophical Magazine’ will be found in vols. i.–xii.
[Philosophical Mag. xii. 275–6 (biographical notice); Anderson's Scottish Nation; Irving's Eminent Scotsmen; Allibone's Dict.]