LEWIS, Enoch, mathematician, born in Radnor, Delaware County, Pennsylvania, 29 January, 1776; died in Philadelphia, 14 June, 1856. He belonged to the Society of Friends. He early exhibited a talent for mathematics, at the age of fourteen was usher in a country school, and at fifteen became principal. In the autumn of 1792 he removed to Philadelphia, studied mathematics, teaching half of each day to earn his support, and in 1795 was engaged as a surveyor in laying out towns in western Pennsylvania. He was in charge of the mathematical department in the Friends' academy in Philadelphia, in 1796-'9, subsequently was mathematical tutor at the Westtown, Pennsylvania, school, and in 1808 opened a private school for mathematical students, which he successfully taught for several years. He edited several mathematical works, with notes, and about 1819 published a treatise on arithmetic that was followed by one on algebra, and by a work on plane and spherical trigonometry. In 1827 he became editor of a monthly called "The African Observer," which continued only one year, and from 1847 till his death he was in charge of "The Friends' Review." His publications include a "Life of Penn" in the "Friends' Library," treatises on "Oaths" and on "Baptism," and a "Vindication of the Society of Friends," in answer to Dr. Samuel H. Cox's "Quakerism not Christianity."--His grandson, Charlton Thomas, lawyer, born in West Chester, Pennsylvania, 25 February, 1834, was graduated at Yale in 1853. He was professor of mathematics, and later of Greek, in Troy university in 1859-'62, deputy commissioner of internal revenue in Washington, D. C., in 1863-'4, managing editor of the New York "Evening Post" in 1870-'1, and secretary of the chamber of life insurance in 1871-'4. He had studied for the ministry of the Methodist church, but abandoned it for law, and now (1887) practises his profession in New York city. He has been for ten years chairman of the Prison association of New York, and has visited in its interest many European prisons, his observations on which have been printed by the association. He has published Bengel's "Gnomon of the New Testament," edited and translated with Reverend Marvin R. Vincent, D. D. (Philadelphia, 1860); "A History of the German People" (New York, 1870); "Harper's Latin Dictionary," with Professor Charles Short (1881); and has In preparation "A School Latin Dictionary."