SIDELL, William Henry, soldier, born in New York city, 21 August, 1810; died there, 30 June, 1873. He was graduated at the United States military academy in 1833, and assigned to the artillery, but resigned in order to follow the profession of civil engineering. He was successively city surveyor of New York, assistant engineer of the Croton aqueduct, and division engineer of railroads in Massachusetts and New York. In the construction of the Panama railroad he acted as chief engineer. He was employed by the United States government on surveys of the delta of Mississippi river. In 1849-'55 he was chief engineer of the railroad between Quincy and Galesburg, Illinois He was appointed in 1859 chief engineer of the: projected Tehuantepec railroad, and had completed the surveys when the political troubles in the United States caused the abandonment of the enterprise.. He volunteered at the beginning of the civil war, but before he received an appointment he was restored to the regular army on its enlargement, with the rank of major, 14 May, 1861. He mustered and organized recruits in Louisville, Kentucky, and Nashville, Tennessee, was also disbursing officer, and planned a system by which more than 200,000 soldiers were mustered in, and at the end of their terms of set-vice disbanded, without errors or delays. From May, 1863, till the close of the war he was acting assistant provost-marshal for Kentucky. He was. promoted lieutenant-colonel of the 10th infantry on 6 May, 1864, and received the brevets of colonel and brigadier-general on 30 March, 1865, and on 15 December, 1870, was retired from service, in consequence of a paralytic attack.