Rare LEVER-DUPLEX ESCAPEMENT Chronograph Antique Pocket Watch

Interesting pocket watch with Lever-Duplex escapement.
Diameter is 47 mm, weight is 70 grams.

Lever Duplex Escapement
The point of lever-duplex was to create detached escapement, while keeping the dead-bit seconds.
The conventional duplex escapement is frictional rest one, while lever escapement release the train several times per seconds.
This way combined lever-duplex escapement is an interesting attempt of making detached escapement with dead-bit seconds. However, disadvantages of duplex escapement remained, and this complicated escapement type was quickly abandoned.


Currently the origin of the escapement seems to be unknown.
The Paul Chamberlain in "It's About Time" presented the sketch of Lever-Duplex escapement, mentioning Fleurier village..
Probably it's indeed production of Fleurier region, as a central hand design is typical for Fleurier watches for Chinese market.

The dust cover bears engraving "Anchor Duplex Chronographe" for Lever Duplex.
The "S/F" letters on regulator for Slow/Fast an half-plate movement design suggests production for American market, probably from 1880s.

Case is unmarked, but tested for 14k gold or better (probably 18k).
Despite the Chronographe signature, it's not a real chronograph, as it not possess stop / reset to zero feature, it's rather a watch with indirect second hand.

Nice and interesting example of watch with special escapement, documenting chronograph development.

Condition
The watch appears to be in quite good condition.
The movement functions, though time keeping is not tested.
Dial is free from defects.
Centre second pause button work as it should.
Case has common period wear.
Mineral glass, original hands.
Watch comes with a key.

Overall very nice condition.