An American Genius - Elmer Ambrose Sperry (1860-1930), American inventor and electrical engineer, who is best known for his inventions based on the application of the gyroscope. He patented more than 400 inventions in his lifetime. Sperry was born in Cortland, New York, and educated at Cornell University. About 1880 he developed a particularly efficient electric-arc light, one of the first in the United States. He was also a pioneer in the manufacture of electric mining machinery, electric streetcars, and electric motors. In 1915 Sperry produced a high-intensity arc searchlight, which was widely used by armed forces during World War I (1914-1918). Sperry's most important invention was the gyrocompass, which, unlike other compasses, was not affected by the magnetism of the earth. It became extremely useful in ocean navigation. From the gyrocompass, Sperry developed the gyropilot for steering ships, and the automatic gyropilot for stabilizing airplanes. Sperry also produced electrically sustained gyros that controlled submarine and aerial torpedoes used during World War I.