Design[edit]
Thomas started to work on his machine in 1818 while serving in the French Army where he had to do a great deal of calculations.[17] He made use of principles from previous mechanical calculators like the stepped reckoner of Leibniz and Pascal's calculator. He patented it on November 18, 1820.
This machine implements a true multiplication where, by just pulling on a ribbon, the multiplicand entered on the input sliders is multiplied by a one-digit multiplier number and it uses the 9's complement method for subtracting. Both of these features will be dropped in later designs.
First machine[edit]
The first machine was built by Devrine, a Parisian clockmaker, and took him a year to build. But, in order to make it work, he had to modify the patented design quite substantially. The Société d’encouragement pour l’industrie nationale was given this machine for review and it issued a very positive report on December 26, 1821.[18] The only known prototype of this time is the 1822 machine on display at the Smithsonian Institution in Washington, D.C.
Production[edit]
Some of the logos used over the years
Manufacturing started in 1851 and ended around 1915. There were about 5,500 machines built during this sixty-year period; 40% of the production was sold in France and the rest was exported.