Mathematician and public official.
Emigrated to Pennsylvania (1768) and worked as a schoolmaster and storekeeper.
Commissioned a brigade major and rendered valuable service to the American cause as a military instructor during the American Revolution.
Professor of mathematics at the University of Pennsylvania (1779-1814). Became a Philadelphia selectman (1799). Director of the United States Mint in Philadelphia (1805- c. 1824).
Elected to the American Philosophical Society (1783); became its president (1819).
Born near Hillsborough, Ireland. Married Amy Hunter Ewing in 1774.