(1803-1889), a famous engineer, born in Sweden. He served for a time in the Swedish army, removed to London in 1826 and later to New York. He is identified with numerous inventions and improvements on steam machinery and its applications. His chief inventions are his caloric engine, the screw propeller, which has revolutionized navigation, and his turret ships, the first of which, the Monitor, distinguished itself in the American Civil War and inaugurated a new era in naval warfare. In his later years he attempted to perfect the solar engine. See MONITOR, THE.