ERNST, Oswald Hubert, soldier, born near Cincinnati, Ohio, 27 June 1842. He entered Harvard in 1858, and two years later was appointed to the U. S. military academy, where he was graduated in 1864, becoming at once 1st lieutenant in the engineer corps. In July 1864, he became assistant engineer of the Army of the Tennessee, and served throughout the Georgia campaign. After a short service at the U. S. military academy as assistant professor of engineering, he was appointed assistant engineer in constructing fortifications on the Pacific coast, and remained s<> occupied till 1868. He was promoted captain in March 1867, had command of an engineer company at Willett's Point. New York, in 1868'71, and in 1870 was sent as astronomer with the government expedition to Spain. to observe the solar eclipse of that year. Later he was appointed instructor of practical military engineering, military signaling, and telegraphy at the military academy, performing also the duties of architect for the more important structures of the place.

In 1878 he became assistant engineer on western River improvements, and in 1880 was given charge of the improvements of the Mississippi River, between the Illinois and Ohio rivers. He received his commission as major in May 1882, and has since had charge of the works of River and harbor improvement in Texas. Major Ernst has written articles on engineering subjects, and has also published "A Manual of Practical Military Engineering" (New York, 1873).