Thomas Jefferson believed in the endless improvement of mankind and was a firm believer in the Enlightenment. Firmly grounded in reason and science, Jefferson was always thinking of ways to improve the world around him and invent new devices. No one was more prolific than Benjamin Franklin in this regard; however, Thomas Jefferson was constantly tinkering, imagining, and thinking of new ways to solve problems. While serving in France as a diplomat for the United States, Jefferson wrote to George Washington on July 17, 1785 about David Bushnell and the idea to combat the British Navy with submersibles. Bushnell famously developed a one-man submarine to attempt to damage British ships in 1776, but was unsuccessful. Thomas Jefferson later popularized the story of Bushnell and his “Turtle” in a lecture to the American Philosophical Society in 1798.

Often, he would take something already in existence and improve it, or use it to meet his needs. Monticello, Jeffferson’s home, is a technological masterpiece including automatically closing doors that use weights and “air conditioning” windows to capture the breeze and cool his home. One of his major improvements was the polygraph, not the lie detector, but a device that mimicked and duplicated his writing so that he also had copies of letters he wrote! Throughout his life, Jefferson will write almost 20,000 letters and many of these are preserved thanks to his innovation and letter duplicating polygraph.

Pictured: Jefferson’s polygraph machine and bust of Jefferson at Monticello in 2024.