Dahlgren, John

Dahlgren, John (Adolphus Bernard) (1809–70) naval officer, inventor; born in Philadelphia. Classically educated, he joined the navy as a midshipman in 1826 and served in the Mediterranean; he served later as an assistant in the U.S. Coast Survey. From 1847 on, as ordnance officer at the Washington Navy Yard, Dahlgren experimented with naval weaponry; by 1851 the yard had begun to produce a cannon of his own design. His 11-inch Dahlgren smoothbore guns were carried aboard many U.S. warships, including the famous ironclad Monitor. As a rear admiral, he commanded the Union's South Atlantic Blockadina Squadron (1863–65) and was commandant of the Washington Navy Yard at his death.