If you can’t do the little things right, you will never do the big things right.
William H. McRaven
The French inventor Alexis Petetin from Besançon (Doubs), was a holder of two French patents (№110349 from 27 Nov. 1875 and №163925 from 27 April 1884) and one German patent (№32148, 24 Jan. 1885) for adding machines. Besides the patent applications, nothing is known about the calculating machines of Petetin, so obviously they remained only on paper.
The first machine of Petetin, Additionneur mécanique (see the nearby patent drawing) is a large 10-key one-column adder (i.e. having the capacity for adding but one digital column at a time) with two 100 teeth result wheels, somewhat similar to the earlier adder of Thomas Hill from 1857. The device features a simple and reliable construction and can be used for sums up to 9999.
The second patent of Petetin is for a small three-key pocket adder (Additionneur de poche à trois touches) and it seems it is the first device of this kind in the history of mechanical calculators.
Button C (see the nearby drawing) is used for entering units, button D is for tens, and button E is for hundreds. The tens carry mechanism is implemented through a resilient shaft c1, which meshes to the next ratchet wheel during the carry.
This portable device can be used only for simple adding operations up to 999. The disadvantage is that wheels are always shifted by only one tooth while pressing a button, so the buttons should be pressed as many times as the sum of corresponding digits. e.g. if you want to enter the number 421 you have to press four times the button E, twice the button D, and once the button C.
Biography of Alexis Petetin
Almost nothing is known about the inventor of these adding machines. Alexis Auguste Petetin was born on 23 November 1826 and died after 1890. He was a luthier and merchant, and in the 1870s and 1880s, he lived in Besançon, Rue Moncey 7. He was married to Marie Othilie Deland (1826-24.01.1890) and they had a daughter—Marie Cécile Petetin (1856-after 1886).