David Rittenhouse
 

David Rittenhouse  (1732-1796), American clockmaker, mathematician, and astronomer, born in Roxborough, Pennsylvania. Rittenhouse displayed an early interest in mathematics and similar studies. When he was 12 years old he inherited the mathematical library and tools of a deceased uncle, and without much instruction he made clocks and instruments as an occupation, establishing himself in Norristown, Pennsylvania. The excellent quality of his clocks and his knowledge of astronomy established his reputation. In 1763 Rittenhouse was commissioned by the Pennsylvania government to survey and determine the first part of what became the Mason-Dixon Line, using surveyor's instruments of his own making. Later he was employed to do survey work on several other state boundaries.

In astronomy he calculated the transit of Venus in 1769 and later made a successful observation of the planet from his Norristown observatory. In 1770 Rittenhouse moved to Philadelphia where he was elected to the provincial legislature in 1775. At the outbreak of the American Revolution (1775-1783) he was a member of the Philadelphia Committee of Safety, becoming its president in 1776. He was also a member of the convention to form the Pennsylvania state constitution and served as state treasurer from 1777 to 1789 and vice provost and professor of astronomy at the University of Pennsylvania from 1779 to 1782. Rittenhouse contributed many papers to the American Philosophical Society and in 1791 became its president, succeeding Benjamin Franklin. The Royal Society of London elected him a fellow in 1795. He was the first director of the United States Mint (1792-1795).