Key figures: David Rittenhouse, Benjamin Franklin, Thomas Jefferson, John Adams
Summary
David Rittenhouse (1732–1796) was America’s foremost astronomer and scientific-instrument maker of the Revolutionary era, and by 1776 his reputation rested on his celebrated orreries and his leadership of the American Philosophical Society’s observation of the 1769 transit of Venus. In 1776 Rittenhouse largely set aside astronomy to serve the Revolution in his native Pennsylvania. He worked as engineer to the Pennsylvania Committee of Safety — overseeing cannon casting, ammunition supply, and the siting of gunpowder mills — was elected on March 2, 1776, to the seat in the Pennsylvania Assembly vacated by Benjamin Franklin, and on July 8, 1776, was chosen a delegate to the convention that drafted the radical Pennsylvania Constitution of 1776. He also sat on the state Board of War. Rittenhouse thus stands as a leading example of the Enlightenment ideal of the scientist-citizen, applying practical skill and republican conviction to the founding of a new nation.
The Self-Taught Philosopher
Rittenhouse was born on April 8, 1732, on a farm at Paper Mill Run near Germantown, Pennsylvania, into a Pennsylvania German family. Largely self-educated, he established himself as a clock- and mathematical-instrument maker at Norriton, teaching himself mathematics, optics, and astronomy from books. His craftsmanship and analytical ability drew the notice of Philadelphia’s learned circles, and in 1768 he was elected a member of the newly reorganized American Philosophical Society, the leading scientific body in British North America. Rittenhouse would hold several of its offices — curator, librarian, and secretary — and serve as its president from 1791 to 1796, succeeding Benjamin Franklin.
The Orreries and the Transit of Venus
Two achievements had made Rittenhouse famous well before 1776. Between about 1770 and 1771 he designed and built two elaborate orreries — mechanical planetariums that modeled the motions of the solar system, capable of representing eclipses and planetary positions for thousands of years forward or backward. One went to the College of New Jersey (later Princeton) and the other to the College of Philadelphia (later the University of Pennsylvania), and the Pennsylvania Assembly voted him a monetary tribute for the accomplishment.
On June 3, 1769, Rittenhouse led one of the American Philosophical Society’s observing parties for the transit of Venus across the face of the Sun, an event that astronomers worldwide used to refine the scale of the solar system. Observing from a purpose-built station at Norriton, Rittenhouse contributed data of a precision that won transatlantic acclaim; by one often-repeated account he was so overcome at the moment of contact that he briefly fainted. The Society published the American observations in the first volume of its Transactions (1771), establishing colonial science as a serious contributor to a coordinated international enterprise.
Engineer to the Committee of Safety
As the imperial crisis turned to war, Rittenhouse placed his mechanical expertise at the service of the resistance. In 1775 he was appointed to the Pennsylvania Committee of Safety — the extralegal body, chaired for a time by Benjamin Franklin, that organized the colony’s defense — and served as its engineer. In this role he supervised the local casting of cannon, the improvement of muskets and rifles, the manufacture and supply of ammunition, and the selection of sites for gunpowder mills and magazines. He experimented with methods of rifling and with the fortification of the Delaware River approaches to Philadelphia, translating the precision of the instrument shop into the practical problems of military supply.
Framing the Pennsylvania Constitution of 1776
Rittenhouse’s standing among Pennsylvania’s radicals carried him into the political heart of the Revolution. On March 2, 1776, he was elected to fill the Pennsylvania Assembly seat that Benjamin Franklin had vacated. When Pennsylvania’s revolutionary movement swept aside the old proprietary government, a convention met in the summer of 1776 to write a new frame of government, and on July 8, 1776, Rittenhouse was elected one of its delegates. He took an active part in the drafting: he served on the committee that prepared the declaration of rights and on the committee for the preamble and oaths, and he presided as chairman while the convention debated the frame of government itself. The resulting Pennsylvania Constitution of 1776 — with its unicameral legislature, plural executive council, and broad taxpayer franchise — was the most democratic of the Revolutionary state constitutions, and Rittenhouse was among the scientific men who lent it their prestige. He also served on the Pennsylvania Board of War.
Significance: The Scientist-Citizen
Rittenhouse embodied, more fully than almost any other American of his generation, the Enlightenment conviction that scientific reason and republican citizenship were of a piece. Thomas Jefferson praised him in Notes on the State of Virginia as a genius equal to any in Europe — a direct rebuttal to Buffon’s thesis of American natural inferiority — and John Adams recorded in his diary that “Rittenhouse is a mechanic; a mathematician, a philosopher, and an astronomer.” After 1776 Rittenhouse continued to serve the new state and nation: he was elected Treasurer of Pennsylvania in 1777 and held the office until 1789, and in 1792 President Washington appointed him the first Director of the United States Mint, a post he held until 1795. His 1776 service marked the point at which the ablest instrument of American science was turned, for a time, entirely to the work of independence.