Dictionary.net

(1803-1889) born in Sweden, early in life gave promise of great achievements in invention. He came to the United States in 1839, and in 1841 produced the war steamer " Princeton," which revolutionized the navies of the world. During the Civil War he was employed in building monitors; the first of which, the " Monitor," destroyed the Confederate ironclad " Merrimac," in 1862. He is the author of a great number of valuable inventions, the most important of which are connected with engines and naval equipments.