Rittenhouse, David

David (1732-1796), an American historian and mathematician. He was born at Germantown and died at Philadelphia. His great-grandfather was a Mennonite from Arnheim, Holland: his mother was a Welsh Quaker. David was a vigorous boy, fond of mechanical inventions. His father set him up as a clock-maker. The activities of Rittenhouse were so numerous and so varied that only the more prominent can be noticed. It is claimed that he worked out independently the system of calculus for which credit is given Leibnitz and Newton. He had reputation as a surveyor. He laid out the boundary between Pennsylvania and Delaware. It is the arc of a circle having a twelve mile radius with the center at Newcastle. He also located the point where the 42d parallel, the boundary between Pennsylvania and New York, crosses the Delaware. As an astronomer, he won no little reputation by computing the parallax of the sun. This he obtained by observing the transit of Venus in 1769. His preparations were made with care. Everything went well. He was so exhausted when the transit was over that he fell in a faint. He was the first to suggest stretching spider lines across the aperture of the telescope.

Rittenhouse took an active part as an engineer during the Revolutionary War. President Washington appointed him director of the first United States mint. For a number of years he was professor of astronomy in the University of Pennsylvania. Mr. Rittenhouse had little or no education of the schools, yet he was recognized by European scientists as one of the most scholarly men living. Membership in various learned societies was conferred on him. In 1790 he succeeded Franklin as president of the American Philosophical Society. He published a number of transactions. Thomas Jefferson said of him, "We have supposed Rittenhouse second to no astronomer living; that in genius he must be first, because he is self taught." A planetarium constructed by him is now in possession of Princeton University.