Joseph Henry

Henry, Joseph (1797–1878), U.S. physicist best known for his electromagnetic studies. His discoveries include induction and self-induction, though in both cases Michael Faraday published findings first. He also devised a much improved electromagnet by insulating the wire rather than the core, invented one of the first electric motors, helped Robert Morse and Sir Charles Wheatstone devise their telegraphs, and found sunspots to be cooler than the surrounding photosphere.

See also: Electromagnetism.