The Curious Case of the Rittenhouse Orrery: Power, Progress, and Providence in the Age of Enlightenment

by: Thomas Apel 

In 1948, in the basement of McCosh Hall at Princeton University, carpenters discovered a dusty old shipping crate containing a curious and largely forgotten machine. Unsure of what it was, much less how it worked, the university took the tangled mass of gears, shafts, and springs to astronomy professor Newton Pierce. Recognizing the object, Pierce declared that it was the once-famous orrery made by astronomer David Rittenhouse in 1770, then purchased for the college for a handsome sum in 1771, only to be lost after it was exhibited at the World’s Fair in Chicago in 1893.  

As Pierce and fellow colleagues set about the arduous task of refurbishing the orrery, they must have wondered how a machine that had once been the school’s prized possession, perhaps the most celebrated American machine of the 18th century, ended up in a basement.   

The Rittenhouse Orrery

Orreries are mechanical models of the universe with moving parts that depict the motions of the heavenly bodies. The more complex orreries were made like clocks, from intricate arrangements of interlocking gears, and like most clocks they were powered by a crank that stored energy in the apparatus. Once wound, the machine slowly unwound, moving the gears and the miniature planetary bodies that were attached. The more precisely made, the more accurately the orreries depicted the motions of heavenly bodies as people of the time understood them.  

Hugely popular in the 18th century, the orrery takes its name from English instrument maker John Rowley, who in 1712 made a model of the earth and moon orbiting the sun and named it an “Orrery” after his patron Charles Boyle, the fourth Earl of Orrery. The first specimen dates to the late 17th century and is credited to the Dutch polymath Christiaan Huygens, a pioneer of mechanical philosophy and inventor of the pendulum clock. While they are still made today, popular appreciation for orreries diminished after the turn of the 19th century.   

 While common in Europe, orreries were almost unheard of in the American colonies before the work of David Rittenhouse. Born in 1732 in Germantown, Pennsylvania, Rittenhouse spent the greater part of his young life in Norriton Township outside of Philadelphia. Though he received little formal education, he took an early interest in mathematics and astronomy, and showed an early aptitude for mechanical pursuits. He read the English translation of Isaac Newton’s Principia Mathematica Philosophiae Naturalis, and built instruments such as clocks, model paper mills, and eventually an observatory. Through his sister’s marriage to Thomas Barton (father of the future botanist William Smith Barton), he was also introduced to philosophical circles beyond Norriton.     

Professing his desire to “astonish the skillful and curious examiner,” Rittenhouse began constructing his orrery sometime in 1767. The machine is first mentioned in the Transactions of the American Philosophical Society of Philadelphia in 1769 under the title “A description of a new ORRERY, planned, and now nearly finished, by DAVID RITTENHOUSE.”  

Completed the following year, the Rittenhouse orrery was like no other. Four foot square with a face made of painted sheet-brass, the orrery was fitted with two large dials. The first centers on the sun, around which travel the known planets Mercury, Venus, Earth, Mars, Jupiter, and Saturn, each with their known satellites. The second dial -- by far the most “astonishing” -- is interlocked with the first and equipped with hands that can be set to specific hours, days, months, and years. Remarkably, Rittenhouse’s machine could be adjusted to show the positions of the planetary bodies at any given moment down to the hour in a 5,000-year period.  

In 1771, Rittenhouse sold the orrery to John Witherspoon, the new president of the College of New Jersey (renamed Princeton in 1896), despite having promised the instrument to his friend, William Smith, provost of the College of Philadelphia (later University of Pennsylvania). The decision was roundly criticized by intellectuals in Philadelphia, who argued that the breathtaking scientific instrument ought not to be sent to a “mere village.” Rittenhouse later made amends, building a second orrery on the same model and giving it to the University of Pennsylvania. 

Rittenhouse and his orrery instantly became important parts of an emerging mythology about American genius and invention. In his Notes on Virginia (1781),Thomas Jefferson used Rittenhouse’s creation to contradict the Comte de Buffon and to prove that America produced greatness: “We have supposed Mr. Rittenhouse second to no astronomer living: that in genius he must be the first, because he is self-taught.” Jefferson’s praise focused on the orrery: “As an artist he has exhibited as great a proof of mechanical genius as the world has ever produced. He has not indeed made a world; but he has by imitation approached nearer its Maker than any man who has lived from the creation to this day.” 

A letter from Rittenhouse to Jefferson describing the math and mechanics of his Orrery.  

In The American Geography (1789), Jedidiah Morse similarly listed Rittenhouse’s orrery first in a long list of American inventions, putting it before the steam engines developed by James Rumsay and John Fitch. And Joel Barlow too presented Rittenhouse’s creation in mythic terms in his epic nationalistic poem, The Columbiad (1807): 

See the sage RITTENHOUSE, with ardent eye, 

Lift the long tube and pierce the starry sky; 

Clear in his view the circling systems roll, 

And broader splendours-gild the central pole. 

He marks what laws th'eccentric wand'rers bind, 

Copies Creation in his forming mind, 

And bids, beneath his hand, in-semblance rise, 

With mimic orbs, the labours of the skies. 

There wond'ring crouds with raptur'd eye behold 

The spangled Heav'ns their mystic maze unfold; 

While each glad sage his splendid Hall shall grace, 

With all the spheres that cleave th'ethereal space. 

All this begs the question: if the Rittenhouse was so much beloved and so widely appreciated in its own time, then why was it left in a basement for more than half a century? What meaning did this instrument have to people in the 18th century and why was it too lost?  

When Immanuel Kant asked the question “what is Enlightenment,” he answered with the statement sapere aude, or “dare to know.” The motto captures the spirit of a time when an increasing number of people in Europe and America conceived sweeping and ambitious projects for the advancement of knowledge. Contrary to their hopes, the 18th century would not be remembered as an epoch of great scientific discoveries, but it did witness a marked expansion of enthusiasm for science, and not just among the well-to-do male social elites who disproportionately practiced science, but among those such as women and children who were not normally welcomed among the ranks of knowledge-makers. 

David Rittenhouse - By Charles Wilson Peale

In this Age of Enlightenment, nothing quite so captivated audiences, particularly in the Anglophone world, as the revelations of Isaac Newton. Presented in meticulous and painstaking detail in the Philosophiae Naturalis Principia Mathematica (1687), Newton’s laws reduced the intricacies of matter, motion, and force to a set of simple rules. As the poet Alexander Pope wrote: 

Nature and Nature's laws lay hid in night:  

God said, "Let Newton be!" and all was light. 

Perhaps most importantly Newton explained gravity and showed that the heavenly bodies were orderly and lawlike in their behaviors -- the universe was the ultimate machine made by the ultimate craftsman. Indeed those who celebrated Newton did so with a mixture of scientific admiration and religious awe, for by laying bare the laws of nature, Newton had done more than anyone to understand God’s design, and thus God itself.   

Given the huge importance accorded to Newton, it was important to have didactic tools available to convey his ideas. For that the Principia Mathematica simply would not do. At three volumes of Latin text (an English translation was offered in 1729), it is a dense read, full of abstruse mathematical equations, and far beyond the ken of novice readers. As Voltaire joked, though the English talked endlessly of Newton, none had actually read him.  

Although the marked expansion of print literature in the 18th century efficiently disseminated knowledge about science, nothing so ably communicated the enthusiasm for science as demonstrations. Presented at private parties and public events, science demonstrations were common and well-attended events, where, for example, showmen scientists revealed the awe-inspiring and sometimes explosive effects of chemical mixtures, and electricians exhibited the wonders of electricity, even letting audience members themselves experience electricity (common idioms about “electrifying audiences” quite literally descend from these events). The spectacle of the scientific demonstration educated and enchanted, imparting to viewers a visceral sense of the powers and mysteries of the natural world.  

Enter the orrery. For people who learned through demonstration, the orrery was the perfect instrument. With its moving parts, the orrery actually showed the movement of the planets and their moons, and it allowed viewers to participate. Besides teaching developing astronomers and college students, the orrery could be used to educate and amaze those who were not pursuing advanced education. As Richard Steele wrote of the device, “It administers the Pleasure of Science to any one …. All Persons, never so remotely employed from a learned Way, might come into the Interest of Knowledge, and taste the Pleasure of it.”          

In 18th-century writing and art, the orrery figures prominently as an educational device, often for woman, children and young students. In one such tract, Astronomical Dialogues between a Gentleman and a Lady (1719), the Englishman John Harris used an imagined conversation between a “lady” and an astronomer as they studied the orrery to highlight the edifying and empowering nature of the orrery:   

Well, said she, I have no words to express the Pleasure and Satisfaction I receive from this most Curious Engine, nor the Amazement the wonderful Contrivance of it gives me. Were my Fortune but half as great as my Curiosity, I would have one of these Instruments as soon as possibly I could get it, and then without being beholding to any of you He-things, I would turn it about myself, till I made it do all I had a mind to. And I wish now, that I could see the Inside of it I, and understand what Numbers of Teeth and Pinions he hath made use of, to produce these various motions.  

In a well-known painting called A Philosopher Lecturing on the Orrery (1765), Joseph Wright of Derby offered an even richer portrait of the scene surrounding the orrery. The tableau centers on the machine itself, which gives off a bright light. In the middle of the scene is the philosopher.  Following common tropes of the era, he is a stern-faced, older man who hovers over the apparatus. Below him, a pair of children laugh, their faces illuminated by the machine. To his side is a student eagerly taking notes, and to his right and left, respectively, are a young man and woman, whose serious expressions suggest sober contemplation of the wonders they are beholding.  

Works like those of Harris and Wright of make it clear that the orrery taught much more than the Newtonian laws of motion. A symbol of rationality and order, as much as it was a didactic instrument, the orrery’s lessons were both physical and moral. Just as Newton’s revelations, rightly considered, exalted the divine architect, so did the orrery, rightly used, promote a deeper appreciation for creation and for the divine providence that oversaw it.  

When John Witherspoon purchased the Rittenhouse orrery in 1771 for the then-considerable sum of £220, he was making a powerful statement about the direction of the College of New Jersey and his aspirations for new knowledge. During his tenure as president, Witherspoon transformed the curriculum of the college, once a nursery for the clergy, introducing courses of study in both moral philosophy, based on the teachings of Francis Hutcheson, and the physical sciences, based on Newtonian models. The orrery had a role in both.  

Born in Scotland in 1723, Witherspoon was an evangelical Presbyterian minister and theologian. Like many of his generation, he admired Newton’s natural but he was primarily interested in moral philosophy, or moral “science.” Moral philosophy doesn’t have a direct modern corollary, although it is the precursor of all the modern social sciences. It was the study of people and their behaviors, and it was dominated by the question of the source of human morality. Like Hutcheson, Witherspoon believed in an innate moral sense -- an inborn capacity that told people right from wrong.   

This was a controversial notion for two reasons. First, if people by their very natures were moral, then they did not need God or religion to be moral. Second, if the moral sense was a sense, then it was possible to construct a moral science. The argument went something like this: if knowledge of natural laws rests on our experience of nature gained through the physical senses, it is possible to build knowledge of moral laws based on our experience of morality gained through our moral sense. Witherspoon ambitiously expected this moral science to be placed on as firm a foundation as Newton had put the physical sciences.  

For Witherspoon, then, the orrery had a dual meaning.  It was at once an instrument for teaching the physical model of the universe, and a powerful symbol of how God’s lawlike design penetrated beyond inert matter, into the human soul itself.  

A Philosopher Lecturing on the Orrery - Joseph Wright of Derby 1766

In the end, Witherspoon’s hope of becoming the Newton of the moral sciences was never fulfilled. His presidency, interrupted by the British occupation of Princeton during the Revolutionary War, lasted until his death in 1794. Though his successor as president, Samuel Stanhope Smith, carried on his vision in the succeeding years, the goals of Princeton and most other American universities changed considerably in the 19th century.   

By 1893, when Rittenhouse’s orrery was left to rot in a basement, much had changed in the landscape of science. While Newtonian physics proved a durable paradigm, the Newtonian universe depicted by the orreries had expanded considerably. For Newton as for Rittenhouse, the universe was composed of six planets, the moon, and a few satellites around Jupiter and Saturn, all set against a canvas of fixed stars. By 1893, astronomers had discovered new planets and moons, and come increasingly to understand that universe was vastly bigger than people a century before realized. And while Newton’s physics still held sway (although even here Einstein was only a decade away), he was no longer revered in the same way, for the 19th century had produced its own heroes of scientific progress in fields such as electromagnetism, thermodynamics, bacteriology, and more. 

Finally, by the end of the 19th century, industrial revolutions had forever altered the nature of craft and production. As steel, steam, and electricity enabled creation on unprecedented scales, some of the finer appreciation for items made with an artisan’s skill and patience was forgotten.    

As for the Rittenhouse orrery, after Pierce and his colleagues rebuilt it in the mid-20th century, the university moved it to Peyton Hall, home of the Astrophysical Sciences Department, where it still resides, a quaint object from a bygone era. But for a time it was much more than that. An instrument for understanding the cosmos and the deity that governed it, the orrery was a potent symbol of power, progress, and providence in the Age of Enlightenment.    

Works Cited and Referenced: 

Maurice Jefferis Babb, “David Rittenhouse,” The Pennsylvania Magazine of History and Biography, Vol. 56, no. 3 (1932), 193-224. 

Joel Barlow, The Columbiad, Book VIII, https://www.gutenberg.org/files/8683/8683-h/8683-h.htm (accessed December 14, 2018). 

James Delbourgo, A Most Amazing Scene of Wonders: Electricity and Enlightenment in Early America (Cambridge, MA: HArvard University Press, 2006). 

John Harris, Astronomical Dialogues between a Gentleman and a Lady, 2nd ed. (London: A. Bettesworth and J. Batley, 1729 [1719]), 172. 

Brooke Hindle, “Witherspoon, Rittenhouse, and Sir Isaac Newton,” William and Mary Quarterly, Vol. 15, no. 3 (July 1958), 365-372. 

William Howell, “A More Perfect Copy: David Rittenhouse and the Reproduction of Republican Virtue,” The William and Mary Quarterly,  Vol. 64, no. 4 (October 2007), 757-79. 

Thomas Jefferson, The Life and Selected Writings of Thomas Jefferson, eds. Adrienne Koch and William Peden (New York: The Modern Library, 2004), 201. 

Richard Kluger, “Rittenhouse Orrery, Bought in 1771 Is Being Rebuilt for Exhibition Here,” Daily Princetonian, Vol. 78, no. 47 (April 1954). 

Jedidiah Morse, The American Geography; Or, A View of the Present Situation of the United States of America (London: John Stockdale, 1792), 341. 

Howard C. Rice Jr., The Rittenhouse Orrery: Princeton’s Eighteenth-Century Planetarium, 1767-1954 (Princeton: Princeton University Library, 1954). 

William Smith, “A Description of an Orrery,” Transactions of the American Philosophical Society, Vol. 1 (Jan. 1769-Jan. 1771), 1-3.