Joseph Henry

Joseph Henry discovered electromagnetic induction independently of Faraday, lost the credit by not publishing quickly, and then built the Smithsonian Institution. He was a watchmaker's apprentice in Albany who came to science late after a chance encounter with a textbook, and taught at the Albany Academy while doing the work that matters. He improved the electromagnet enormously by insulating the wire and winding it in many close turns, producing magnets that could lift a ton where earlier ones lifted a few pounds, and he distinguished the quantity magnet from the intensity magnet, which is what allowed a current to be sent usefully down a long wire. That is the physical basis of the electric telegraph, and he built a working one across a mile of wire in 1831; he never patented anything, holding that scientific discoveries should be free, and later testified for Samuel Morse in the patent suits before falling out with him over how much Morse acknowledged. He found self-inductance in 1832, and the SI unit of inductance is named the henry for it. He became the first secretary of the Smithsonian in 1846 and ran it for thirty-two years, resisting proposals to make it a national university or a museum and insisting on original research and publication, which is the shape it kept. He also set up a network of volunteer weather observers reporting by telegraph, which became the National Weather Service. He advised Lincoln on military technology during the war. His name is less known than Faraday's or Morse's because he was in a hurry about nothing except giving things away. He was the first president of the National Academy of Sciences to serve a full term and chaired the lighthouse board, improving the lamps on the American coast. Alexander Graham Bell brought him the idea for the telephone and was told to go and get it.

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