Thomas Arithmomètre

The French insurance salesman Charles Xavier Thomas (1785-1870) from Colmar in Alsace manufactured his Arithmomètre since 1820. It was a 4-species stepped drum machine which had, in the spirit of the Industrial Revolution, been designed from the start for series production. It became the first commercially used mechanical calculating machine, for which Thomas enjoyed a worldwide monopoly during the years 1820 to 1878. From 1858 onwards the Thomas machines featured a multi-place revolution counter (without tens-carry) and a cancelling gadget for all windows. In 1879 it became known that Thomas had produced about 1200 machines by 1875, that he had sold about 800 by 1870, and by 1878 a further 700 of which 60 percent were exported. Production of the machines was in the hands of A.M. Hoart whose factory was in the building of the insurance company “Le Soleil” in Paris. This machine bears the number 1203 which indicates that it was built in 1875. It has a 9-place revolution counter and a revolving mechanism via toothed rods for clearing the revolution counter and the result mechanism. It bears a signet next to the setting mechanism reading “Thomas de Colmar Paris, Inventeur, No. 1203“. Unfortunately the machine has been defaced by scratched numerals along the places of the result mechanism. Its original wooden case did not survive, thus it is housed under a perspex hood.