LONG, Stephen Harriman, engineer, born in Hopkinton, New Hampshire, 30 December, 1784; died in Alton, Illinois, 4 September, 1864. He was graduated at Dartmouth in 1809, and after teaching for some time entered the United States army in December, 1814, as a lieutenant in the corps of engineers. After discharging the duties of assistant professor of mathematics at the United States military academy until April, 1816, he was transferred to the topographical engineers, with the brevet rank of major. From 1818 till 1823 he had charge of explorations between Mississippi river and the Rocky mountains, and of the sources of the Mississippi in 1823-'4, receiving the brevet of lieutenant-colonel. The highest summit of the Rocky mountains was named Long's peak in his honor. He was engaged in surveying the Baltimore and Ohio railroad from 1827 till 1830, and from 1837 till 1840 was engineer-in-chief of the Western and Atlantic railroad in Georgia, in which capacity he introduced a system of curves in the location of the road and a new kind of truss bridge, which was called by his name, and has been generally adopted in the United States. On the organization of the topographical engineers as a separate corps in 1838, he became major in that body, and in 1861 chief of topographical engineers, with the rank of colonel. An account of his first expedition to the Rocky mountains in 1819-'20 from the notes of Major Long and others, by Edwin James, was published in Philadelphia in 1823, and in 1824 appeared "Long's Expedition to the Source of St. Peter's River, Lake of the Woods, etc.," by William H. Keating (2 vols., Philadelphia). Colonel Long was retired from active service in June, 1863, but continued, charged with important duties, until his death. He was a member of the American philosophical society, and the author of a "Railroad Manual" (1829), which was the first original treatise of the kind published in this country.