Jefferson's Astronomical Case Clock

One of the most poignant of Jeffersonian artifacts is a 1782 scrap of paper with a quotation from the novel Tristram Shandy, written in Martha Wayles Jefferson’s hand but then taken up by her husband Thomas, as she was too weak to finish. Beginning with the phrase “time wastes too fast,” the snippet goes on to lament the fleeting nature of time for lovers about to be parted. Although this was a favorite passage from a favorite novel, Jefferson’s ideas about time were not always so romantic. In fact, Jefferson’s more scientific side is on full display at Monticello in a treasure-trove of timekeeping devices ranging from sundials to gongs, to various types of clocks. 

If time is money, it is also order, control, efficiency, mathematics and physics: all concepts used by Jefferson to mold the world of his household and the enslaved inhabitants of his plantation. Many are familiar with the deservedly famous Great Clock at Monticello, which displays Jefferson’s ingenuity, love of precision (it has a hand that ticks the seconds!), and his desire to put the organizing principle of time at the very center of his estate. But let’s look at a few of the many timekeeping devices beyond the Great Clock and see how they impacted all those who lived at Monticello.

The interior of the astronomical clock, with the days of the week marked in similar fashion to the Great Clock in the Hall

Visitors to Monticello have always loved the Great Clock, but Jefferson’s favorite may have been the astronomical clock kept in his personal suite from 1812 onward. This one was the result of his desire since the 1770s to have an instrument so precise that it could be used in astronomical observations, such as charting eclipses. Because Jefferson planned to use it only for that purpose, this astronomical clock had no need for a chiming mechanism. Nor did it have an astronomical clock’s usual dials showing the relative positions of the sun, moon, planets, and constellations. In his directions to the maker, Jefferson specified that “no unnecessary labour [was] to be spent on mere ornament. [A] plain, but neat mahogany case will be preferred….”  Although it may look quaint to modern eyes, this timepiece was very high-tech, of a type usually found in astronomical observatories and not in private homes.  

Gilt bronze mantel clock from Paris

When visiting Monticello, it is interesting to try to spot the many timekeeping devices, but sometimes they point themselves out, as when one of the small mantel clocks delicately chimes the hour or half-hour. In the dining room may be found a gilt bronze French Neoclassical clock, a lovely example of a mantel clock. This timepiece features marble columns and other motifs from the classical past, emblems of the timeless wisdom of antiquity. Even in a decorative object, Jefferson conveyed messages about the nature of time itself and the aspiration to transcend it.

Jefferson's Obelisk Clock

Another small clock was very visible to Jefferson each morning as he arose “with the sun.” The spare, elegant marble and brass obelisk clock on the wall at the end of his bed was made in 1791 from Jefferson’s sketch and precise instructions, which featured the face suspended between two obelisks. The clock held such significance to Jefferson that after his death his daughter Martha called it the object “I should have prized beyond anything else.”  The timeless obelisk form was persistently interesting to him, all the way to his self-designed obelisk-shaped grave marker.

Jefferson’s 1790 sketch for his obelisk clock

In Jefferson’s day, visitors would have been fascinated by a three-dimensional outdoor timekeeper: the spherical sundial, possibly the only such instrument in North America at the time.  Mounted like a globe with the exact tilt of the earth toward the sun at Monticello’s latitude, and marked off into 5-minute increments, the solar time can be read with reasonable accuracy by placing the iron bar where the least shadow is cast. The spherical sundial is yet another way of marking and telling time at Monticello, this one without any mechanical parts at all.

2001 reproduction of Jefferson’s spherical sundial, on the North Terrace

For Jefferson, time-keeping was not just a scientific delight, but it was a method of mastery and control. His Great Clock not only constantly reminded those in the house, both enslaved and free, where they were in a time-ordered world, but Jefferson took the idea to the rest of the plantation when he installed a roof gong. The gong, which sounded on the hour, was meant to “serve as the bell to a clock, which might be heard all over my farm.” This device was thus largely aimed at the enslaved population working in distant fields and workshops, keeping them too on Jeffersonian time.

A rather simple tall case clock today stands in the corner of the kitchen in the South Wing. Why did Jefferson install such an expensive device in the work area of the house? Isaac Granger, enslaved blacksmith at Monticello, recalled that the only times Jefferson went into the kitchen were to wind the clock. Keeping mealtimes, and thus enslaved cooks, on a precise schedule was evidently a matter of significance to Jefferson.

The roof gong as it is housed today, a conjectural restoration of the original

Next time you visit Monticello, be sure to seek out the many timekeeping devices inside the house and out, from the Great Clock to the spherical sundial. As you do, you may want to ponder the various ways that Jefferson delighted in the science of timekeeping, and how he sought to use time to order and control every aspect of his domain.


This blog post was made possible in part by a major grant from the National Endowment for the Humanities. Any views, findings, conclusions, or recommendations expressed in this program do not necessarily represent those of the National Endowment for the Humanities.