The first version of this counter is called an observation counter, and is a simple way of measuring events lasting up to an hour.
The second version is called the billiard counter. It works on the same principle, but the "zero" is at 7 o'clock. The central hand indicates the elapsed time, but also the price to be paid according to the length of play, with a scale for play during the day and another for play in the evening!
Finally, the third version, known as the "observation counter", combines a billiard counter with zero at noon and a small dial at 6 o'clock, where a particular time can be memorized by means of a small thumbwheel.
These counters had a brief existence: in October 1911, the Léonidas factory in St Imier went bankrupt and was put up for auction. Constant Jeanneret-Droz bought it.