I believe that when you left America the invention of the Polygraph had not yet reached Boston. it is for copying with one pen while you write with the other … I think it the finest invention of the present age … knowing that you are in the habit of writing much … I have accordingly had one made [for you] … as a Secretary which copies for us what we write without the power of revealing it, I find it a most precious possession to a man in public business.
To James Bowdoin, July 10, 1806
Patrick Lee’s Explanation
Far-sighted leaders promote new inventions.
Jefferson owned a polygraph, “the finest invention of the present age,” a device for making copies of letters. (Here’s another image, which better illustrates how it folded up for transport.) It consisted of two ink pens suspended over two sheets of paper. The pens were held together by a series of wooden arms and hinges. When one of the pens was lowered onto the paper to write, the second pen followed along and made an identical copy. There were polygraphs with three and four ink pens for making multiple copies, but they were more difficult to use.
He loved the polygraph for several reasons. He kept a copy of everything he wrote. It allowed him to make a copy without having a secretary duplicate one from his original. Thus, he could keep his correspondence private. The polygraph was portable, and he traveled regularly between Washington City and Monticello. Finally, he simply loved inventions and machines. (He tinkered with Hawkins’ design to make it work better!)
What a polygraph cost in 1806 is anyone’s guess, but for sure, it was not cheap. Jefferson loved his new device so much he had one made for Bowdoin, an American minister to Spain. One of the lesser factors in Jefferson’s ever-increasing debt was his tendency to shower gifts on his friends, whether he had the cash to pay for them or not.
While Jefferson was devoted to his polygraph, it was not a commercial success. It took too much adjustment to keep in proper working order. That was not a problem for a man who loved to tinker.
P.S. To prove his point, Jefferson added his own P.S. to this letter, telling Bowdoin he was reading the pages made from the copying pen, not from the pen he held in his hand.