Thomas Arithmomètre

This is probably one of the first commercially produced machines built by the French mechanic Charles Xavier Thomas. He began producing machines in 1850. Several features of the machine point to its early production: the container at the right-hand side of the setting mechanism, on later machines at the left-hand side, the addition/subtraction switching gadget, the inscribed signet and, of course, the low machine number. Around 1858, his son patented the improved version with revolution counter, which is another indication of the early date of the machine. This machine already looks very nearly like those that were subsequently produced for about sixty years (see FDM 9140, 9398, 8303).