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builder of one of the first American observatories
David Rittenhouse was born near Germantown, Pennsylvania, on April 8, 1732. Having little opportunity to attend school, he got most of his education from books and a box of tools inherited from his uncle, a furniture maker. The limited education must have been enough, however, as he was able to open an instrument and clock-making shop at the age of nineteen. In 1763, using devices made in his shop, Rittenhouse surveyed the Pennsylvania border to help settle a boundary dispute with Maryland. His measurements were so accurate that he was subsequently commissioned to survey the borders of many other colonies, and he held the post of City Surveyor of Philadelphia in 1774.
In 1767, Rittenhouse constructed the first of two working models of the solar system (called orreries), which could show the solar and lunar eclipses and other phenomena for a period of 5,000 years either forward or backward. One of the orreries went to the College of New Jersey (now Princeton), the other to the College of Philadelphia (now the University of Pennsylvania). In 1768 he built an observatory in Philadelphia -- with what was likely the first telescope made in America -- to watch the planet Venus pass across the sun. He maintained detailed records of his observations and published a number of important works on astronomy, including a paper in which he detailed how to locate the place of a planet in its orbit. In 1786 he introduced the use of spider lines in the focus of a transit instrument.
A respected member of the scientific community, Rittenhouse was elected a member of the American Philosophical Society in 1768, and served as the society's president from 1791 to 1796. Over the years he received a number of honorary degrees, and was elected a member of the American Academy of Arts and Sciences and a fellow of the Royal Society of London. He was also Professor of Astronomy at Philadelphia College from 1779 to 1782, Vice-Provost of Philadelphia College in 1780 and 1782, trustee of the University of the State of Pennsylvania from 1779 to 1780 and 1782 to 1791, and trustee of the University of Pennsylvania from 1791 to 1796.
During the Revolutionary War, Rittenhouse served on the Committee of Safety as an engineer supervising local casting of cannon, improvement of rifles, and location of gunpowder mills and magazine stores. He subsequently served in the Pennsylvania Assembly, in the Pennsylvania Constitutional Convention of 1776, and on the Board of War. Rittenhouse also served as Treasurer of Pennsylvania from 1779 to 1787, and from 1792 to 1795 as the first director of the United States Mint.
David Rittenhouse died in Philadelphia on June 26, 1796.
This page was last updated on 04/07/2017.