“Machine arithmétique” by René Grillet

In 1678, French watchmaker René Grillet presented the “Machine arithmétique”, a calculating machine, he himself had created.
Constructed largely out of paper, the invention used so-called Napier’s rods that had been around since 1617 for the calculation process.
It is an excellent example of the early days of mechanical calculation and an ancestor of today’s pocket calculator. Photo: Jan Braun, HNF