On October 12 Auction Team Breker offers this Arithmomètre from 1865 guided at €3000-5000. (Photo copyright 2019 by Auction Team Breker.)

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It was designed by Charles Xavier Thomas, who later took on the name of his home town and called himself Thomas de Colmar. While working as the Inspector of Supply for the French army he had the idea for a machine to facilitate complicated calculations mechanically.

The first version of his Arithmomètre, which was based on earlier so-called stepped drum reckoners, was constructed in 1820 by a Parisian clockmaker called Devrine. However, it was not until 1857 that Thomas began seriously marketing his invention.

The Arithmomètre, which was adapted and improved over the years, was the first mass produced calculating machine and sold for Fr500 apiece – a considerable sum in those days.

In the following years Thomas nevertheless found buyers for over 1000 of them. He had already acquired an impressive fortune in the insurance business and the proceeds of the sales increased his wealth further. When he died in 1870, he left over Fr24m.