John Gross Barnard, an American military engineer, brother of President F. A. P. Barnard, born in Berkshire county, Mass., May 19, 1815. He graduated at West Point in 1833, and was assigned to the engineer corps, in which he has since served, having been promoted as follows: lieutenant, 1833; captain, 1838; brevet major, 1848; major, 1858; brigadier general of volunteers, 1861; brevet colonel, 1862; lieutenant colonel, 1863; brevet major general of volunteers, 1864; brevet brigadier general and brevet major general of the regular army, March 13, 1865; colonel of the corps of engineers, Dec. 28, 1865. Up to 1846 he was employed as constructing engineer on the southern coasts and at New York and New Orleans. During the war with Mexico he fortified Tampico, and made surveys of the battlefields around the capital. In 1850-'51 he was chief engineer for the survey of the projected Tehuantepec railroad, and afterward acted as engineer of various public works. In 1855-'6 he was superintendent of the military academy at West Point, and for the next four years he had charge of the defences around New York. At the opening of the civil war he was intrusted with the fortifications around Washington, served as engineer for the army of the Potomac, and finally, on the staff of Gen. Grant, as chief engineer to the armies in the field.

He was mustered out of the volunteer service in 1866; and, with the actual rank of colonel of the corps of engineers, he is a member of boards having in charge the fortifications and harbor and river obstructions of the territory of the United States. He has published "The Gyroscope" (1857), and "Problems in Rotary Motion" (1872), two very profound mathematical investigations; " Dangers and Defences of New York" (1859); "Notes on Seacoast Defence " (1861); "The C. S. A. and the Battle of Bull Run" (1862); and "Artillery Operations of the Army of the Potomac" (1863). In 1864 the degree of LL. D. was conferred upon him by Yale college.