(b. Paper Mill Run, near Germantown, Pennsylvania, 8 April 1732; d. Philadelphia, Pennsylvania, 26 June 1796)
technology, astronomy, natural philosophy.
Rittenhouse, the son of Matthias and Elizabeth Williams Rittenhouse, was raised on his father’s farm in Norriton, about twenty miles north of Philadelphia. His paternal ancestry was German Mennonite and maternal, Welsh Quaker, but no strong denominational loyalty was encouraged in his home. In his mature years, Rittenhouse maintained a Presbyterian Church membership. His education was largely informal, and he was regarded as self-taught. On 20 February 1766 he married Eleanor Coulston, by whom he had two daughters; following her death, he married Hannah Jacobs toward the end of 1772. Rittenhouse’s health was seldom good but seldom seriously impaired, the primary difficulty probably being a duodenal ulcer. Except for the wartime occupation, surveying expeditions, and summers in Norriton, he spent most of his life after 1770 in Philadelphia.
As one of the leading Philadelphia mechanics, Rittenhouse played an important role in the American Revolution. He participated in formulating the radical Pennsylvania Constitution of 1776 and served on the Board of War and as vice-president of the Council of Safety—with occasional responsibility for executive leadership of the state. From 1777 through 1789 he was treasurer of Pennsylvania.
Basically, Rittenhouse was a maker of clocks and mathematical instruments. His long-case clocks were novel not in their mechanism but in their fine workmanship. Three included small orreries, one had only a single hand, and his astronomical clock used a compensation pendulum of his own design. His masterpieces in clockwork were two large orreries in which he achieved beauty and a high degree of precision. Rittenhouse’s instruments, many of which have been preserved, were superior to those previously produced in America. He made surveyors’ compasses, levels, transits, telescopes, and zenith sectors as well as thermometers, barometers, at least one hygrometer, and occasional eyeglasses. He made early use of spider webs for cross hairs in telescopes, and he erected a collimating telescope in his observatory. Rittenhouse’s fine surveying instruments were used for laying out national boundaries years after his death. Because he constructed vernier compasses, they became known in America as Rittenhouse compasses; and his improvement on Franklin’s Pennsylvania fireplace was called the Rittenhouse stove.
Most of Rittenhouse’s science and much of his nonpolitical service were closely related to his making of clocks and instruments. Starting as a manufacturer of surveying instruments, he became the most celebrated American surveyor, serving on commissions that marked portions of Pennsylvania’s boundaries with Maryland, New Jersey, New York, and what became the Northwest Territory, and portions of New York’s boundaries with New Jersey and Massachusetts. Beginning in 1773, Rittenhouse supplied the astronomical calculations for almanacs in Pennsylvania, Maryland, and Virginia. During the Revolution he helped to design the Delaware River defenses and worked on the production of saltpeter and guns—including experimentation with telescopic sights for rifles and rifled cannon. He provided informed advice when Thomas Jefferson was working out his report on weights and measures; and as first director of the U.S. Mint (1792–1795), he produced and put into operation machinery that was new to him but for which his clockmaking career had prepared him.
Astronomy was Rittenhouse’s primary scientific study, a pursuit to which he moved easily from his orreries, telescopes, and surveying. He began to study mathematics and science at an early age, first attaining recognition in the observation of the transit of Venus of 1769, which was important because of worldwide efforts to establish the sun’s parallax. On this occasion Rittenhouse emerged as the leading figure in the American Philosophical Society’s observations and in its initial volume of Transactions. He made many of the instruments and assembled all of those used by the Norriton observation group; he carried through key related observations and projections and contributed to the best American calculation of the parallax. Rittenhouse established a Philadelphia observatory, where he kept daily records and conducted regular observations, publishing data and calculations on meteors, comets, Jupiter’s satellites, Mercury, Uranus (following its discovery), and various eclipses. In calculating planetary orbits and positions, he worked out some solutions of his own. Rittenhouse’s mathematical work was largely related to the study of astronomy, his best paper being an original solution for finding the place of a planet in its orbit. He also devised an arithmetical method for calculating logarithms and published a paper on the sums of (he several powers of the sines—an offshoot of a study of the period of a pendulum.
Rittenhouse’s other work in science was experimental, except for descriptive accounts of the effects of lightning and a few papers on meteorology, geology, and aspects of natural history that he published in magazines. He experimented with various compensation pendulums, with the expansion of steel, and with the expansion of wood—for which he obtained good values. After familiar experiments with magnetism, Rittenhouse produced a very clear statement of the concept of magnetic dipoles. In an investigation of diffraction, he constructed plane transmission gratings, using fine wire across a frame. With one of these gratings he observed six orders of spectra, obtained good values for their angular displacement and clearly stated the law governing their displacement. Rittenhouse also studied and correctly reported the primary causes of the illusion of reversible relief. This work was picked up and passed into subsequent literature after his death. Even this paper, however, was characteristic of most of his work, in that it represented an isolated study, not part of a continuing dialogue or investigation.
Rittenhouse succeeded Franklin as president of the American Philosophical Society, which he strengthened in its role as a platform of science; nearly all of his scientific papers were published in its Transactions. His craftsmanship supported science by providing precise scientific instruments. More directly, he contributed data and new information as well as several fruitful ideas in fields now widely separated. Although he wrote occasional speculative and mathematical pieces and others on the history of science, his scientific contributions were almost wholly observational and experimental.
I. Original Works. All of Rittenhouse’s papers, unless otherwise noted, are in Transactions of the American Philosophical Society. His papers on the transit of Venus are “Projection of the Ensuing Transit of Venus,” in Transactions, 1 (1771), 4; “Observations at Norriton,” ibid., 13–22; “Account of the Contacts,” ibid., 26–28; “Delineation of the Transit of Venus,” ibid., 36–38; and [Method of Finding Parallax], ibid., appendix, 59–60.
Other astronomical papers are “Observations on the Comet,” in Transactions, 1 , 37–45; “An Easy Method of Deducing the True Time of the Sun’s Passing the Meridian,” ibid., 47–49; “Account of a Meteor,” ibid., 2 (1786), 173–176; “New Method of Placing a Meridian Mark,” ibid., 181–183; “Observations of a Comet,” ibid., 195; “Astronomical Observations,” ibid., 260–263; “Astronomical Observations,” ibid., 3 (1793), 153–155; and “An Account of a Comet,” ibid., 261.
His mathematical papers are “A Method of Finding the Sum of the Several Powers of the Sines,” in Transactions, 3 , 155–156; “To Determine the True Place of a Planet,” ibid., 4 (1799), 21–26; and “Method of Raising the Common Logarithm,” ibid., 69–71.
His experimental papers are “Explanation of an Optical Deception,” in Transactions, 2 , 37–42; “An Account of Some Experiments in Magnetism,” ibid., 178–181; “An Optical Problem,” ibid., 202–206; “On the Improvement of Timekeepers,” ibid., 4 , 26–28; and “On the Expansion of Wood by Heat,” ibid., 28–31. The orrery paper is “A Description of a New Orrery,” in Transactions, 1 (1771), 1–3.
On lightning and electricity, he wrote “Account of Several Houses in Philadelphia Struck With Lightning,” in Transactions, 3 , 119–122, with John Jones; “An Account of the Effects of a Stroke of Lightning,” ibid., 122–125, with Francis Hopkinson; and “Experiments on the Gymnotus electricus,” in Philadelphia Medical and Physical Journal, 1 , pt. 2 (1805), 96–100, 159–161.
His papers on natural history are in Columbian Magazine, 1 (1786–1787), 49–53, 284, 301–303. His essay on the history of astronomy is An Oration (Philadelphia, 1775). Locations of MSS and of clocks and instruments are in Hindle (below).
II. Secondary Literature. The most recent biography is Brooke Hindle, David Rittenhouse (Princeton, 1964). William Barton, Memoirs of the Life of David Rittenhouse (Philadelphia, 1813), is of continuing value for its insights and for excerpts of letters now lost. The most important evaluations of aspects of Rittenhouse’s science are Thomas D. Cope, “The Rittenhouse Diffraction Grating,” in Journal of the Franklin Institute, 214 (1932), 99–104; and W. Carl Rufus, “David Rittenhouse as a Mathematical Disciple of Newton,” in Scripta mathematica, 8 (1941), 228–231.
Rittenhouse, David (1732-1796)
David Rittenhouse (1732-1796)
Astronomer, clockmaker, and president of the american philosophical society
Early Years. Benjamin Franklin’s successor as president of the American Philosophical Society was David Rittenhouse, America’s foremost scientist in the last part of the eighteenth century. Born near Germantown, Pennsylvania, in 1732, Rittenhouse showed remarkable mechanical and mathematical abilities as a child. At seventeen he built a clock shop at the family farm. Clockmaking was his principal occupation for twenty years, although he also worked as a surveyor, establishing the official boundary line between Pennsylvania and Maryland (1763) and between New York and New Jersey (1769). His success as a clockmaker led him to other kinds of mathematical instruments. As a member of the American Philosophical Society he built an observatory at his farm. Later, at his home in Philadelphia, he built another, the first permanent astronomical observatory in America. It is also believed that Rittenhouse made the first telescope in America to observe the transit of Venus (1769).
Revolutionary Patriot. During the Revolutionary War Rittenhouse was a military engineer, supervising the manufacture of weapons and ammunition. One of his more unusual ideas in collaboration with Thomas Paine was a flaming iron arrow, which they hoped to use to destroy British fortifications at Philadelphia. Rittenhouse also became more involved in public affairs as a member of the Pennsylvania Assembly and the state constitutional convention in 1776. The next year he served as the president of the Pennsylvania Council of Safety. After the war he continued his public career, serving as Pennsylvania state treasurer until 1789, and he also returned to surveying, “running the line” between Pennsylvania and New York (1786) and New York and Massachusetts (1787). Later he was appointed professor of astronomy at the University of Pennsylvania, where he made various discoveries in the fields of astronomy, optics, and magnetism. Among his many inventions was a thermometer made of two strips of different metals, as in modern bimetallic thermostats, and a collimating telescope. In 1791 Rittenhouse began a five-year tenure as president of the American Philosophical Society. Between 1792 and 1795 he also acted as first director of the U.S. Mint, where he organized the department and supervised the minting of the first U.S. coin, a silver five-cent piece.
The Orrery. Rittenhouse was most famous in his lifetime for his elaborate mechanical planetarium, called an “orrery,” that showed the movement and position of planets orbiting a sun. Originally built sometime around 1767, the mechanism was “so accurately adjusted,” he wrote, “as not to differ sensibly from the tables of Astronomy in some thousands of years.” His orrery also included “a most curious contrivance for exhibiting the appearance of a solar eclipse, at any particular place on the earth.” (One of Rittenhouse’s orreries is now at the Franklin Institute in Philadelphia, and another at Princeton University.) Jefferson was awestruck when he saw it. “He has not indeed made a world,” he wrote, “but he has by imitation approached nearer its Maker than any man who has lived from the creation to this day.” Rittenhouse died in 1796.
Howard C. Rice Jr., The Rittenhouse Orrery (Princeton, N.J.: Princeton University Library, 1954).
David Rittenhouse (1732-1796), American astronomer and instrument maker, was a noted amateur scientist who constructed the finest orrery made at that time.
David Rittenhouse was born on April 8, 1732, near Germantown, Pa., into a poor farming family. He was stimulated by some books and tools of his uncle's and evidently educated himself in mathematics and astronomy. With help and encouragement from an Episcopal clergyman, he continued to advance his mathematical knowledge. In 1763 his boundary survey for Pennsylvania was so accurate that it was later accepted by the English surveyors Charles Mason and Jeremiah Dixon.
In 1767 Rittenhouse began his masterwork, the finest and most accurate orrery of that period. This mechanical representation of the movement of the planets through the universe was used widely in teaching and demonstration in the 18th century and also served as a demonstration of the reasonableness of nature. Rittenhouse's first orrery was capable of reproducing the relations of the planets forward or backward 5,000 years and emitted music when in operation.
Rittenhouse was in demand over the next few years by colleges that wanted him to make orreries, and the Commonwealth of Pennsylvania awarded him £300 as an honor and £300 more to make an orrery "for the use of the public." The fame derived from his orrery guaranteed him support for his observations in 1769 of the transit of Venus, which was an opportunity to measure the solar parallax. Rittenhouse's observations, made in a specially constructed laboratory, with instruments of his own design, were highly accurate and were favorably considered by European scientists working on the same problem.
In 1770 Rittenhouse moved to Philadelphia, where he was able to pursue a more active scientific career. He became a member of the informal scientific circle presided over by Thomas Jefferson. With his own improved telescopes he continued to make astronomical observations and to produce scientific and surveying instruments for himself and others, while making his living as a clockmaker. There is some uncertainty as to whether he independently developed a system of calculus, but he did become mathematically sophisticated and made some contributions in this area.
During the Revolutionary War, Rittenhouse was an avid patriot, serving on councils and committees of public safety, devising harbor defenses and methods of saltpeter production for gunpowder, and substituting iron weights in pendulum clocks to get lead for bullets. His last public service was as director of the U.S. Mint from 1792 to 1795. He died of cholera on June 26, 1796. He is often cited as an example of the untutored genius springing from American soil.
The best biography is Brooke Hindle, David Rittenhouse (1964).Edward Ford, David Rittenhouse: Astronomer-Patriot, 1732-1796 (1946), is also useful. For general background relating to Rittenhouse and the Jeffersonian circle see Daniel J. Boorstin, The Lost World of Thomas Jefferson (1948), and Brooke Hindle, The Pursuit of Science in Revolutionary America, 1735-1789 (1956).
Hindle, Brooke, David Rittenhouse, New York: Arno Press, 1980, 1964. □
American astronomer and instrument-maker known for the fine workmanship of his clocks and scientific devices. He produced high precision telescopes, thermometers, surveyor's compasses, and other instruments that were superior in quality to anything previously produced in America. His scientific interests were diverse, but astronomy was his primary interest. He observed the 1769 Venus transit and contributed to the best American calculations of solar parallax. Rittenhouse also played an important role in the American Revolution.