1911 Encyclopædia Britannica/Dahlgren, John Adolf
DAHLGREN, JOHN ADOLF (1809–1870), admiral in the U.S. navy, was the son of the Swedish consul at Philadelphia, Pennsylvania, and was born in that city on the 13th of November 1809. He entered the United States navy in 1826, and saw some service in the Civil War in command of the South Atlantic blockading squadron. But he was chiefly notable as a scientific officer. His knowledge of mathematics caused him to be employed on the coast survey in 1834. In 1837 his eyesight threatened to fail, he retired in 1838–1842, and in 1847 he was transferred to the ordnance department. In this post he applied himself to the improvement of the guns of the U.S. navy. He was the inventor of the smooth bore gun which bore his name, but was from its shape familiarly known as “the soda water bottle.” It was used in the Civil War, and for several years afterwards in the United States navy. Dahlgren’s guns were first mounted in a vessel named the “Experiment,” which cruised under his command from 1857 till 1859. They were “the first practical application of results obtained by experimental determinations of pressure at different points along the bore, by Colonel Bomford’s tests—that is by boring holes in the walls of the gun, through which the pressure acts upon other bodies, such as pistol balls, pistons, &c.” (Cf. article by J. M. Brooke in Hamersley’s Naval Encyclopaedia.) When the Civil War broke out, he was on ordnance duty in the Washington navy yard, and he was one of the three officers who did not resign from confederate sympathies. His rank at the time was commander, and the command could only by held by a captain. President Lincoln insisted on retaining Commander Dahlgren, and he was qualified to keep the post by special act of Congress. He became post-captain in 1862 and rear-admiral in 1863. He commanded the Washington navy yard when he died on the 12th of July 1870.
A memoir of Admiral Dahlgren by his widow was published at Boston in 1882. (D. H.)