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Astro*Dictionary by Michael Erlewine





1 article for "Henry, Joseph"

Henry, Joseph [Astro*Index]

(1797-1878) American physicist. Born at Albany, NY; died at Washington, DC.

The unit of inductance, the henry, is named in his honor. His work with electromagnets led Wheatstone and Morse to the development of the telegraph; his discovery of induction preceded that of Faraday, who published first; but, in 1831, his electric motor (which has changed the world) was announced. In 1846, he was made first secretary of the Smithsonian Institution. And, in 1848, he showed that sunspots were cooler than other locations on the Sun, by making sensitive heat measurements of the solar image projected onto a white screen.


Astro*Index Copyright © 1997 Michael Erlewine