: born in Sheffield, Mass.
, May 19, 1815; was graduated at the United States Military Academy in 1833, and entered the engineer corps.
He was made captain in 1838; major in 1858; brevet brigadier-general
of volunteers in 1861; lieutenant-colonel
of regulars in 1863; brevet major-general
of volunteers in 1864; brevet brigadier-general
and brevet major-general of regulars, March, 1865; and colonel of the corps of engineers, regular army, Dec. 28, the same year.
During the war with Mexico
he fortified Tampico
, and made surveys of the battle-fields around the capital.
In 1850-51 he was chief engineer of the projected Tehuantepec Railroad; and in 1855-56 he was superintendent of the United States Military Academy.
He was chief engineer of the Army of the Potomac, 1861-62; also chief engineer of the construction of the defences of the national capital from September, 1862, to May, 1864.
He was chief engineer of the armies in the field on General Grant
's staff, from May, 1864, until Lee
's surrender at Appomattox
in April, 1865.
At the close of the war he was brevetted major-general, U. S. A.
He published The Gyroscopc
and Problems in rotary motions
, which evince profound mathematical investigation; also other works concerning the Civil War
and its operations.
The degree of Ll.D. was conferred upon him by Yale College.
He died in Detroit, Mich.
, May 14, 1882.