Joseph Henry

Joseph Henry was born December 17, 1797, and built his name winding electromagnets in the 1820s and early '30s. While doing that work he discovered self-inductance, the property that makes a coil resist changes in its own current, and independently found mutual inductance around the same time Faraday did - though Faraday published first. Henry turned the electromagnet from curiosity into tool, invented a bell that rang at a distance via electric wire in 1831, and in 1835 built the electric relay, the switch that made long-distance telegraphy possible for Morse and Wheatstone. In 1846 he became the first secretary of the Smithsonian Institution and held the post until his death on May 13, 1878, also serving as president of the National Academy of Sciences for the last decade of his life.