A Polygraph is a duplicating device that produces a copy of a piece of writing simultaneously with the creation of the original, using pens and ink.
Patented by John Isaac Hawkins on May 17, 1803, it was most famously used by the third U.S. president, Thomas Jefferson, who acquired his first polygraph in 1804 and later suggested improvements to Charles Willson Peale, owner of the American rights.[1] Because Jefferson was a prolific letter writer, the preservation of his copies have offered historians extensive insights into Jefferson's viewpoints and actions.[2] Jefferson called the polygraph "the finest invention of the present age".[3][4] A description of Jefferson's office routine in his own words may be read online.[5]
Another American, Benjamin Henry Latrobe was the first customer of Peale's and not only introduced the device to Jefferson but was also instrumental in its improvement.[6]
Mechanisms of this type are more generally known as pantographs, which include simple devices for making copies at various enlargements or reductions by tracing over a drawing.
Marked "Hawkins & Peale's Patent Polygraph No. 57," this machine was used by Jefferson from 1806 until his death. Jefferson first acquired the letter-copying device he called "the finest invention of the present age" in March of 1804. .... Before he returned to England in 1803, Hawkins assigned his American patent rights to Charles Willson Peale, who developed and marketed the invention. Jefferson was one of his most eager clients, purchasing one for the President's House and one for Monticello. He soon exchanged these machines for new ones, as Peale continued to perfect the design — often according to Jefferson's suggestions. By 1809 Jefferson wrote that "the use of the polygraph has spoiled me for the old copying press the copies of which are hardly ever legible . . . . I could not, now therefore, live without the Polygraph."Archived July 27, 2019, at the Wayback Machine.