Ericsson

John, an American inventor; born in Sweden, July 31, 1803; entered the Swedish army in 1820; was promoted captain; resigned in 1827. He soon became known as an inventor. In 1828 he made the first application to navigation of the principle of condensing steam and returning the water to the boiler; later he brought out a self-acting gunlock by means of which naval cannon could be automatically discharged at any elevation without regard to the rolling of the ship. In 1833 he designed a caloric engine; and in 1836 invented the screw propeller, which revolutionized navigation. Eric on came to the United States in 1839 and two years later built the screw-propelling warship “ Princeton”’ for the government. This ve el was the pioneer of modern naval construction and the foundation of the steam marine of the world. The achievement, however, which made him most famous in the United States was the construction in 1861 of the ironclad ‘ Monitor,” which was launched 100 days after its keel was laid, and which arrived in Hampton Roads just in time to defeat, on March 9, 1862, the Confederate ironclad “ Merrimac,” which had destroyed several wooden warships. But for this signal victory the result of the war might have been changed and European interference attempted. A fleet of monitors was soon built and did important service during the remainder of the war.