<Tr> <Th> Alma mater </Th> <Td> The Albany Academy </Td> </Tr> <Tr> <Th> Known for </Th> <Td> Electromagnetic induction, Inventor of a precursor to the electric doorbell and electric relay </Td> </Tr> <P> Joseph Henry (December 17, 1797--May 13, 1878) 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 . He was highly regarded during his lifetime . 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 . Henry developed the electromagnet into a practical device . He invented a precursor to the electric doorbell (specifically a bell that could be rung at a distance via an electric wire, 1831) and electric relay (1835). The SI unit of inductance, the henry, is named in his honor . Henry's work on the electromagnetic relay was the basis of the practical electrical telegraph, invented by Samuel F.B. Morse and Sir Charles Wheatstone, separately . </P> <P> Henry was born in Albany, New York, to Scottish immigrants Ann Alexander Henry and William Henry . His parents were poor, and Henry's father died while he was still young . For the rest of his childhood, Henry lived with his grandmother in Galway, New York . He attended a school which would later be named the "Joseph Henry Elementary School" in his honor . After school, he worked at a general store, and at the age of thirteen became an apprentice watchmaker and silversmith . Joseph's first love was theater and he came close to becoming a professional actor . His interest in science was sparked at the age of sixteen by a book of lectures on scientific topics titled Popular Lectures on Experimental Philosophy . In 1819 he entered The Albany Academy, where he was given free tuition . Even with free tuition he was so poor that he had to support himself with teaching and private tutoring positions . He intended to go into medicine, but in 1824 he was appointed an assistant engineer for the survey of the State road being constructed between the Hudson River and Lake Erie . From then on, he was inspired to a career in either civil or mechanical engineering . </P>

Which american inventor invented the commercial telegraph based on joseph henry work