Swiss pocket watch with a remarkable duplex escapement Circa 1850

Nickel open faced pocket watch
–
An experimental Swiss pocket watch with a remarkable variation of a duplex escapement, circa 1850.
1/2 plate movement, compensation balance with inner screws, polished nickel case. Enamel dial with radial Roman numerals, outer minutes track, subsidiary dial for the seconds, and spade hands.
–
Diameter: 54 mm
–
Weight: 134 g
–
Signed: No name
–
This watch has a kind of duplex escapement in the form of two escapement wheels with one above the other. However, for each tooth on the upper wheel, the lower one has three smaller teeth, which makes for a running noise of several quiet ticks to one louder one. Equally unusual is the winding mechanism, where a retractable pin turns the barrel on the back, which extends over the complete plate. The back has 12 numbered indentations as well as a central screw; what these were intended for is a mystery, however, quite possibly some part of the construction has been lost over the years so that we cannot understand the concept of the system.