Jefferson and the Polygraph 
Thomas Jefferson first acquired the letter-copying device he
called "the finest invention of the present age" [1]
in 1804. It was invented by English-born John Isaac Hawkins, who
gave it the name "polygraph." Based on the principles of the pantograph
[2], it had two or more pens that were moved
simultaneously by the writer's hand, making a duplicate copy or
copies strikingly like the original.
Hawkins received an American patent for his invention -- which he described as an "Improvement in the pentagraph and parallel ruler" -- in 1803. When he returned to England in that year, he assigned the American rights to the polygraph to artist and museum director Charles Willson Peale of Philadelphia. Peale, who was a lifelong friend of Jefferson, began production of the device, making additional improvements to it.
Jefferson, who used only the two-pen models, received his first polygraph in March of 1804, soon returning it for another. He bought a second one [3] for use at Monticello and regularly exchanged his machines for new ones, as Peale, often according to Jefferson's suggestions, continued to perfect the design.
In 1804 Jefferson abandoned his copying press and for the rest of his life used exclusively the polygraph for duplicating his correspondence. Two of his polygraphs survive, one in the American Philosophical Society, and the other, shown in this Apple QuickTimeVR Object Movie (polygraph.mov, 460K), on display at Monticello.
--Lucia C. Stanton, Monticello Research Department, September
1989
SOURCE:
Silvio A. Bedini, Thomas Jefferson and His Copying Machines (Charlottesville, 1984)
FOOTNOTES:
[1] Jefferson to James Bowdoin, 10 July 1806
[2] An instrument in the form of a flexible parallelogram used for duplicating plans and drawings.
Pictured: Jefferson's polygraph; photograph by Edward Owen, courtesy of the University of Virginia