1911 Encyclopædia Britannica/Rittenhouse, David
RITTENHOUSE, DAVID (1732-1796), American astronomer, was born at Germantown, Pennsylvania, on the 8th of April 1732. First a watchmaker and mechanician he afterwards became treasurer of Pennsylvania (1777-89), and from 1792 to 1795 director of the U.S. mint (Philadelphia). He was largely occupied in 1763 and in 1779-86 in settling the boundaries of several of the states. He was a fellow of the Royal Society of London, and a member of the American Philosophical Society; and was elected president of the latter society in 1791. As an astronomer, Rittenhouse's principal merit is that he introduced in 1786 the use of spider lines in the focus of a transit instrument. His priority with regard to this useful invention was acknowledged by E. Troughton, who brought spider lines into universal use in astronomical instruments (see von Zach's Monatliche Correspondenz, vol. ii. p. 215), but Felice Fontana (1730- 1805), professor of physics at the university of Pisa, and afterwards director of the museum at Florence, had already anticipated the invention in 1775, though no doubt this fact was unknown to Rittenhouse. His researches were published in the Transactions of the American Philosophical Society (1785-1799). He died at Philadelphia on the 26th of June 1796.