The patent model of Thomas de Colmar’s Arithmomètre from the year 1820

Charles Xavier Thomas applied for a patent on his first Arithmomètre in 1820. This design model would later lead to the first mechanical calculating machine for all four basic arithmetic operations successfully manufactured in series production – it was manufactured and sold starting around 1855. For the 200 year celebration of the year the patent on this extraordinary calculating machine was granted, the Arithmeum plans an anniversary exhibition with numerous original machines that is planned to start in autumn 2021.

As his bachelor’s thesis, Jan Bachmann reconstructed the no longer existing patent model and made a great 3D animated video about it. We would like to thank the National Museum of American History – Smithsonian Institution for giving us the opportunity to examine the calculating machine from 1822 and announcing that they want to offer us this machine as a temporary loan for the exhibition. Of course, our thanks also go to Thomas expert Valéry Monnier who gave us very well-informed advice in questions of detail.

Charles Xavier Thomas’ Arithmomètre is a great success as a calculating machine – mechanically, functionally and aesthetically speaking. Its appeal is already revealed in the patent model.