Biography

Charles Sumner is mentioned as one of Henry's acquaintances, and Sumner asks WHS to "remember him to his old friend Dr.Henry," in his letter from 18580000. 

Joseph Henry was an American scientist who served as the first Secretary of the Smithsonian Institution. He was the secretary for the National Institute for the Promotion of Science, a precursor of the Smithsonian Institution. While building electromagnets, Henry discovered the electromagnetic phenomenon of self-inductance. He also discovered mutual inductance independently of Michael Faraday, though Faraday was the first to make the discovery and publish his results. The SI unit of inductance, the Henry, is named in his honor.