CLARK, Thomas, author, born in Lancaster, Pennsylvania, in 1787: died in Philadelphia, Pennsylvania, in 1860. He was educated at St. Mary's College, Baltimore (Roman Catholic), but declined to take orders and was appointed a lieutenent of the 2d artillery, 1 April, 1813, becoming assistant topographical engineer, with the rank of captain, on the same day. During the war of 1812 he was engaged in constructing the defenses on the Delaware river. He was mustered out of service in June, 1815, and devoted himself to literature, becoming editor of Latin and Greek classics for the Association of Philadelphia booksellers. He published a "Naval History of the United States from the Commencement of the Revolutionary War," highly commended by John Adams and Thomas Jefferson (2 vols., Philadelphia, 1813-'4), and "Sketches of the Naval History of the United States" (1813).