In the Civil War, he served as assistant engineer in the Army of the Potomac during the Peninsular campaign and in the northern Virginia campaign, and from July, 1864, to September, 1865, commanded as colonel, a regiment of veteran volunteer engineers. During the war he received the successive brevets of captain, major, lieutenant colonel, and colonel for gallant services. He published Iron Truss Bridges for Railroads (1870) and Improvement of Non-Tidal Rivers (1881).