biography
| sex:
| male
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| lived:
| (1732–92)
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| biography:
| Instrument maker, inventor, and astronomer, born in Paper Mill Run, Pennsylvania, USA. Largely self-taught, he was a mathematical prodigy and showed a talent for mechanics. By the age of 19 he was an innovative clockmaker, and during his early twenties he was making telescopes, credited with being the first to introduce the use of cross hairs (spider web) in transit telescopes. Using his own instruments, he became a student of astronomy and went on to make several important contributions, including a calculator of the Sun's parallax. As a surveyor, he was responsible for establishing the basis of what became the Mason and Dixon line demarking Pennsylvania from Maryland, and this led to his employment as a surveyor to settle boundary disputes. In c.1770, when he moved to Philadelphia, he constructed two orreries that displayed planetary motions. (One survives at the Franklin Institute in Philadelphia.) He continued to work at and publish a variety of scientific and mathematical problems. During the American Revolution he served with the Philadelphia Committee of Safety, and oversaw the manufacture of arms and munitions. A member of the convention that produced Pennsylvania's constitution (1776), he was state treasurer (1777–89), a teacher of astronomy at the University of Pennsylvania (1777–89), a commissioner who set up the First Bank of the United States (1791), and first director of the US Mint (1792–5). In 1791 he succeeded Benjamin Franklin as president of the American Philosophical Society and was elected a fellow of the Royal Society (1795). At his death he was regarded as the foremost American scientist and mathematician of the day. |
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