COMSTOCK, Cyrus Ballou, soldier, born in West Wrentham, Massachusetts, 3 February, 1831. He was graduated at the United States military academy in 1855, standing first in his class, and became second lieutenant in the corps of engineers. From that time until 1859 he was engaged in the construction of Fort Taylor, Florida, and Fort Carroll, Maryland, after which he was assistant professor of natural and experimental philosophy at West Point. During the civil war he served in the defenses of Washington, District of Columbia, becoming in August, 1861, assistant to the chief of engineers in the Army of the Potomac. He continued with this army through the peninsular campaign of 1862, and the Maryland campaign, and was made chief engineer in November, 1862. After Fredericksburg and Chancellorsville he was transferred to the Army of the Tennessee, and was its chief engineer, being present at the siege of Vicksburg. Later he became assistant inspector of the military division of the Mississippi, and from March, 1864, till the close of the war was senior aide-de-camp to General United States Grant, serving in the Richmond campaign of 1864-'5, at Fort Fisher, and in General Canby's Mobile campaign. From 1866 till 1870 he served as aide to the general-in-chief at Washington, and since that time has been occupied as superintendent of geodetic survey of the northern and northwestern lakes, and on other important surveys, including the improvements of the mouth of the Mississippi. In 1881 he became lieutenant colonel in the engineer corps, and he holds the brevet ranks of brigadier-general in the regular army and major general of volunteers. He was appointed in 1882 a member of the board of engineers for fortifications and River and harbor improvements. General Comstock was elected a member of the National academy of sciences in 1884. He has published "Notes on European Surveys" (Washington, 1876); "Survey of the Northwestern Lakes" (1877); and "Primary Triangulation, United States Lake Survey" (1882).