When Thomas Jefferson served as the U.S. Minister to France in the late 1780s, he frequently took trips into the European countryside. In addition to enjoying the natural landscape, Jefferson took the opportunity to learn about European agricultural practices in hopes of bringing new ideas home to the United States. When he observed the plows used in the French countryside, he noted inefficiencies and resolved to improve on the design.
Over the next few years, Jefferson applied concepts from his study of Euclidean geometry and Newtonian calculus to create a design for a plow’s mouldboard that would reduce resistance.
As a statesman and political philosopher, Jefferson believed that the future of the American Republic was rooted in the soil. He envisioned an agrarian society of independent, family-sized farms and citizens imbued with the virtues of self-sufficiency, humility, individual liberty, and respect for the natural world. In his book Notes on the State of Virginia, Jefferson asserts that “those who labor in the earth are the chosen people of God.” He imagined that an agrarian America would be immune to the corruption and exploitation that he associated with rising systems of manufacturing and commercial capitalism; he was somehow capable of disassociating from these views the corruption and exploitation inherent in Southern agriculture’s reliance on enslaved labor. Nonetheless, Jefferson applied himself to studying and improving farming practices in the United States.
While we know Jefferson primarily as an American statesman, he was also an Enlightenment thinker, dedicated to educating himself on all available knowledge. He taught himself calculus from reading Newton’s Principia and studied advanced geometry from Robert Simson’s Elements of Euclid.
Jefferson’s agrarian ideals and mathematical interests came together in his design for what he called “the mouldboard plow of least resistance.”
The plow, which Jefferson described as “the most useful of the instruments known to man,” cultivates the soil for the planting of crops. Essentially, the blade at the base of the plow pierces the sod and dislodges the soil as it moves through the field. The mouldboard is the wedge-like surface behind the plowshare that receives the soil, gradually lifts it, and then turns it over as it falls back to the ground. Jefferson commented that “the plow is to the farmer what the wand is to the sorcerer,” and he applied some mathematical magic to improve on the design of this essential tool.
Jefferson’s plan for an improved mouldboard relied on precise angles to reduce resistance, thus minimizing the exertion of force required by the mule and the farmer. Jefferson also used advanced geometry and calculus to identify the exact curvature that would allow the mouldboard’s shape to turn the soil exactly 180°, thus bringing the deeper, nutrient-rich soil to the field’s surface. As Jefferson wrote in a 1794 letter to an agricultural reformer and politician named John Taylor, the new plow’s design was “mathematically demonstrated to be perfect, as far as perfection depends on mathematical principles.”
Jefferson spent five years in the fields of Monticello testing and tinkering with the design of his plow. By 1798, he was pleased enough with the performance of his prototype that he wrote to Sir John Sinclair, a British leader in scientific agriculture, that his new design “answers in practice to what it promises in theory.”
Jefferson’s letter to Sinclair gives an overview of the mathematics involved in the design and provides detailed instructions for how to construct the plow. This letter was published in the 1799 issue of Transactions, the journal of the American Philosophical Society. In this piece, Jefferson explains the innovations and effects of his mouldboard plow design. In providing instructions on how to build it, Jefferson specifies where and how deeply to saw into the block of wood. Jefferson supplements his written directions with a series of 2D and 3D geometrical figures that illustrate the design. He did not seek a patent and allowed the details of his design to be printed and published widely within the United States and abroad.
In 1802, when Jefferson was serving the first term of his Presidency, the design for his mouldboard plow was translated into French and published as a pamphlet along with enhanced diagrams. At the top of the pamphlet, Jefferson is explicitly identified as “président des États-Unis d’Amérique.” Indeed, he was celebrated internationally for his contributions to agricultural science: the British Board of Agriculture elected Jefferson to a foreign honorary membership in 1797, the French Societe d’Agriculture du Département de la Seine awarded him its gold medal in 1805, and the Italian Agricultural Society in Florence conferred upon him an honorary degree for “excellenza.”
Jefferson applied his brilliant mind toward the improvement of society on both macro and micro levels with equal idealism and vigor. As he writes in the concluding paragraph of his letter to Sinclair describing his design for an improved plow, “we are advancing towards a better state of things […] which tend eminently to ameliorate the condition of man.” In his ingenious conception of his mouldboard plow — and in his decision to share its design freely with academics and agricultural laborers alike — he was modeling the kind of virtuous collaboration that he believed was essential to a successful republic.
In this way, Thomas Jefferson was not only a founding father, but also a founding farmer.
Sources and Further Reading:
Betts, E. M. (ed.) (1999). Thomas Jefferson’s Farm Book. Charlottesville, Thomas Jefferson Memorial Foundation.
Boles, J. B. (2017). Jefferson: Architect of American Liberty. New York: Basic Books.
Griswold, A. W. (1946). “The Agrarian Democracy of Thomas Jefferson.” The America Political Science Review, vol. 40, no. 4. American Political Science Association.
Krall, L. (2002). “Thomas Jefferson’s Agrarian Vision and the Changing Nature of Property.” Journal of Economic Issues, vol. 36, no. 1. Taylor & Francis.
Martin, R. L. and Stanton, L. C. Thomas Jefferson Encyclopedia. “Moldboard Plow.” monticello.org.
Miller, A. C. (1942). “Jefferson as Agriculturist.” Agricultural History, vol. 16, no. 2. Agricultural History Society.
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