Colmar Arithmometer -Upper cover

This arithmometer was constructed in 1820 and patented on 18th November the same year by Xavier Thomas de Colmar. As opposed to previous machines, this was able to carry out basic operations (addition, substraction, multiplication, division) easily and without mistakes, giving results from up to 12 digits. Nevertheless, it couldn't save in its memory a partial result neither carrying out calculations in sequence. It is considered as the first successful commercial calculator and a role model in the XIX century. There is a model of the arithmometer in the Torres Quevedo Museum.

Upper cover with its engraved name.