In 1899 the French engineer Georges Lafond from Paris received several patents in different countries for a simple calculating device (Austrian patent №6618, German patent №148810, US patent No. 653250, Great Britain patent №189902195, and Swiss patent №19395). The calculator of Lafond was an interesting watch-like circular adding machine (see the nearby photo).
In fact, the patents described three different but similar adding devices:
1. A model based on the duodecimal system in the shape of a watch although this counter can be made in any other shape.
2. A model based on the decimal system for any sort of totalization.
3. A model based on the French monetary system.
Only one of the above-mentioned devices (the circular one) went into production, although in small quantities. This stylus-operated disk adder was in production since the early 1900s, manufactured by a famous watchmaker workshop from Geneva—Haas Neveaux & Cie.
The calculator of Lafond is a metal chromium device, with diameter 47 mm, and four sunk silvered revolving counters each with an aperture. In fact, it is a simple form of circular four-dial Pascaline type calculator where a stylus is used to move the individual wheels to carry out addition and subtraction.