DESAGULIERS (John Theophilus)
, an eminent experimental philosopher, was the son of the Rev. John Desaguliers, a French Protestant refugee, and born at Rochelle in 1683. His father brought him to England an infant; and having taught him the classics himself, he sent him at a proper age to Christ-church College, Oxford; where in 1702 he succeeded Dr. Keil in reading lectures on experimental philosophy at Hart Hall. In 1712 he married, and settled in London, when he first of any introduced the reading of lectures in experimental philosophy in the metropolis, which he continued during the rest of his life with the greatest applause, having several times the honour of reading his lectures before the king and royal family. In 1714 he was elected F. R. S. and proved a very useful member, as appears from the great number of his papers that are printed in their Philos. Trans. on the subjects of optics, mechanics, and meteorology. The magnificent duke of Chandos made Dr. Desaguliers his chaplain, and presented him to the living of Edgware, near his seat at Cannons; and he became afterward chaplain to Frederick prince of Wales. In the latter part of his life, he removed to lodgings over the Great Piazza in Covent Garden, where he carried on his lectures with great success till the time of his death in 1749, at 66 years of age.
He was a member of several foreign academies, and corresponding member of the Royal Academy of Sciences at Paris; from which academy he obtained the prize, proposed by them for the best account of electricity. He communicated a multitude of curious and valuable papers to the Royal Society, for the year 1714 to 1743, or from vol. 29 to vol. 42.
Beside those numerous communications, he published a valuable Course of Experimental Philosophy, 1734, in 2 large vols. 4to; and gave an edition of Gregory's Elements of Catoptrics and Dioptrics, with an Appendix on Reflecting Telescopes, 8vo, 1735. This appendix contains some Original Letters that passed between Sir Isaac Newton and Mr. James Gregory, relating to those telescopes.
