American general, born at Cadiz, son of an American merchant; he passed through West Point and joined the engineers; he served in the Mexican War, became captain and major, and was employed surveying and lighthouse building till the Civil War; in it, first in command of volunteers and afterwards as general in the regular army, he distinguished himself chiefly by frustrating Lee in 1863; after the war he continued in the service till his death at Philadelphia (1815-1872).