Swiss gold keyless wind open face pocket watch Circa 1880

Unique pocket watch with perpetual calendar
–
A gentleman’s unique Swiss pocket watch with perpetual calendar and chronograph, circa 1880.
This watch was sold in 1882 with Patek Philippe extract from the archives.
18k gold case signed PPC, enamel dial, bridge movement, gold screw compensation balance.

A total of 35 watches with perpetual calendar are known that were produced between 1862 and 1934 with no reference number.
This timekeeper  however  is a remarkable and unique piece we know of no other watch with perpetual calendar and chronograph function.
A slider near the crown sets the chronograph pusher. The back is decorated with an engine-turned pattern and a beautifully executed engraved monogram.
–
Diameter: 52 mm
–
Weight: 137 g
–
Signed: Patek Philippe & Co.  Geneva