A second pen followed the first
The machine worked by linking two pens with a set of movable arms. As a person wrote with one pen, the connected pen traced the same movements on another sheet. The writer supplied the motion; the mechanism carried it to both nibs at once. That made a second copy as the writing was being produced, rather than by copying it afterward.
This was more than a faster way to make duplicates. Because the second pen followed the writer’s hand, it could reproduce the individual shapes and flourishes that made a signature look personal. In an era when official business relied heavily on handwritten documents, that ability had an obvious use—and an obvious risk. A device that made legitimate copies could also make an unauthorized signature harder to distinguish from the original.
From suspicion to everyday correspondence
The Paris police seizure in 1795 shows how quickly a clever writing tool could become a matter of public concern. The machine did not decide what to write or imitate someone on its own: a person had to produce the movements. Its power came from turning one act of handwriting into two near-simultaneous records.
Refined versions later became useful to U.S. presidents, who could create a duplicate as they wrote a letter. That saved the need to rewrite important correspondence simply to keep a copy. The same basic mechanism therefore served opposite purposes: it raised fears about forged signatures while helping officials preserve their own written records. A copied signature could be produced by a machine, but the hand guiding it still mattered.
