Analysis of information sources in references of the Wikipedia article "Polygraph (duplicating device)" in English language version.
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.
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.
