Jefferson’s Polygraph Machine

Almost every day, Thomas Jefferson wrote letters. “From sun-rise to one or two o’clock,” he noted, “I am drudging at the writing table.” Jefferson wrote almost 20,000 letters in his lifetime, and he needed to keep copies of his letters. Fortunately, John Isaac Hawkins (1772–1855) and Charles Willson Peale (1741–1827) invented this little gadget that …

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