1.Previous
3.Next

parallel to one held by a writer, enabling the writer to make a duplicate of a document as it is written. Polygraphs appeared in the 17th century but did not become popular until 1800. John Isaac Hawkins and Charles Willson Peale patented a polygraph in the US in 1803, and beginning in 1804 Thomas Jefferson collaborated with them in working on improvements in the machine. He used a polygraph for the rest of his

1.Previous
3.Next