Dear Mr. Mudd:

Q: What is an orrery, and how did Princeton University come to own one? How was it damaged in the Battle of Princeton?

A: An orrery is a mechanical model of the solar system. Orreries were regarded as essential teaching equipment for 18th-century lectures on “natural philosophy” (the physical sciences). Although invented ca. 1700 by George Graham, they have been called orreries because English instrument maker John Rowley named a copy he made of Graham’s machine “The Orrery” in honor of Charles Boyle, Earl of Orrery.

David Rittenhouse, a Pennsylvania clockmaker, self-taught astronomer, and later the first director of the U.S. Mint, designed and built the College of New Jersey’s orrery (now Princeton University). In 1771, College President John Witherspoon purchased it from Rittenhouse for approximately £220 and installed it in Nassau Hall. The orrery instantly became the College’s most valuable asset. Rittenhouse’s original plans for the orrery included a central panel of four square feet showing the planets revolving around the Sun, and two smaller panels, one focused on Jupiter and Saturn, and the other on the Earth and the Moon, but all that remains today is the central panel, after damages during the military occupation of Nassau Hall in 1776-1777. A more complete example of a Rittenhouse Orrery has been preserved at the University of Pennsylvania Library.

The Continental Army drove the British away from campus on January 3, 1777.  Afterward, when travelers passed through Princeton on the way to the nation’s new capitol (Philadelphia), they frequently stopped to see the sights: Nassau Hall (the largest building in  North America) and the orrery.

Thomas Jefferson cited the orrery as evidence that America produced geniuses, a praise echoed by Jedediah Morse in 1789. Joel Barlow praised it in poetry in 1807. Although very popular, the orrery was in need of repair, as John Witherspoon noted in 1784, when he wrote that the war had almost completely destroyed the College library, and had left “the Orrery much injured.” The State of New Jersey came to the rescue in 1796, with an “Act Concerning the College of New Jersey” providing funding to repair campus buildings, the library, and, of course, the orrery. The Board of Trustees minutes record that the College sent the orrery to Henry Voight of Philadelphia for repairs in 1804, at a cost of $500 (roughly $10,000 in 2014 dollars).

Americans felt deep resentment for the British occupation of the College of New Jersey in December 1776 and early January 1777. Damages to the orrery were initially attributed to the British:

When repairs were finished in 1808, College officials admitted that most of the damage actually came  from American soldiers, who had removed and taken the wheels “as handsome curiosities.” Ashbel Green, Class of 1783 and later president of the College, wrote about the orrery toward the end of his life, corroborating the claims of the College officials. The British naturally took offense at these false accusations. Nonetheless, many continued to believe that the British, rather than the Americans, had been the cause of the damage.

After serving as a notable teaching aid for the first half of the 19th-century, the orrery’s usefulness in the classroom faded, and it became a mere curiosity, hidden away for years before being brought out to be included in Princeton’s exhibit at the Chicago World’s Fair in 1893. It was then packed away and returned, but never unpacked, its whereabouts a complete mystery until 1948. Carpenters working in the basement of McCosh Hall discovered the orrery in its World’s Fair shipping box and brought it to Astronomy Professor Newton Pierce for identification. Because of its damaged condition, the orrery’s re-discovery was not publicized until the spring of 1951. Thanks to the generosity of Bernard Peyton (Class of 1917), the orrery was restored and equipped with electric motors. It remained in Firestone Library for a time, where it formed the focus of an exhibition in 1954. Upon completion of construction of Peyton Hall in 1966, the orrery was loaned to the Astrophysical Sciences Department, and it is still on display in the Peyton Hall lobby today.

Related Sources

Astrophysical Sciences Department Records, 1835-1988. See Box 24: Folder 2.

Historical Photograph Collection, Campus Life Series, c. 1850-1996

Historical Subject Files Collection, 1746-2005

Leitch, Alexander. A Princeton Companion. (Princeton, New Jersey: Princeton University Press, 1978). Also available online.

Office of Communications Records, 1922-1995

Princeton Alumni Publications, Inc., Editor’s Records, 1895-1929

Princeton Alumni Weekly Photograph Collection, c. 1968-c. 1991

Rice, Howard C., Jr. The Rittenhouse Orrery: Princeton’s Eighteenth-Century Planetarium, 1767-1954: A Commentary on an Exhibition held in the Princeton University Library. (Princeton, New Jersey: Princeton University Library, 1954). Manuscript and other materials related to Rice’s books are housed in the Princeton University Archives.

This post is an expanded version of an FAQ by Stasia Karel that appeared on our website in 2003. It has been revised and posted here as part of the pending launch of a new Mudd Library website.