Joseph Henry

Joseph Henry (b. Albany, NY, USA, 17th December 1797, d. Washington, USA, 13th May 1878) was a pioneer in the field of electromagnetism. The SI unit of inductance was named after him as the Henry (H). He was born to a poor family of Scottish descent and raised as a Presbyterian, a faith he followed throughout his life. His elementary education was in Albany and Galway, New York, where he stayed with relatives. Henry was apprenticed to an Albany watchmaker and silversmith. The theater was his principal interest as an adolescent, until a chance reading of George Gregory's Popular Lectures on Experimental Philosophy, Astronomy, and chemistry turned him to science. In 1819 he enrolled in the Albany Academy and remained there until 1822, with a year off to teach in a rural school in order to support himself. He did odd surviving jobs while he was doing his scientific research. in 1825, Henry was appointed professor of mathematics and natural philosophy at the Albany Academy. In 1832, he accepted a chair at the College of New Jersey.
Henry's earliest known work was in chemistry. In 1827, he started active research on electricity and magnetism. Throughout his career, Henry was interested in terrestrial magnetism and other geophysical topics. He independently uncovered the sense of Ohm's law and engaged in impedance matching. In 1832, Henry discovered self-inductance following some experiments. He also conducted investigations on capillarity, phosphorescence, heat, colour blindness and the relative radiation of solar spots with skill and imagination. His 1835 paper was on the action of a spiral conductor in increasing the intensity of galvanic currents. He conceived of astronomy as the model science and mechanics as the ultimate analytical tool. Henry could not accept Faraday's field concept because of his belief in central forces acting in a universal fluid. He concluded that the currents are oscillatory wave phenomena exciting equivalent effects in an electrical plenum coincident, if not identical, with the universal aether.
Henry formed the Smithsonian Committee, consisting of dedicated men forming internationally recognized standards and engaging in free and harmonious intellectual intercourse among themselves. Being the secretary of the Smithsonian, he was not interested in popularizing science but with supporting research and disseminating findings.