Polygraph Duplicator

The printing press is for mass production, mass duplication of a single document. The polegraph duplicator was used to produce two copies of hand written documents at the point of origin. A machine consisting of two pens connected by a series of levers, springs and hinges made it especially useful for letter writing. But if you didn't have a copy of the letter you sent and you don't remember what you asked, you're in trouble there.