Swiss rose gold open faced lever pocket chronometer Circa 1884

Rose gold keyless lever watch by Louis Audemars
–
A very fine and rare Swiss 18 carat rose gold open faced keyless lever pocket chronometer, circa 1884. Shipped to Audemars’ stock depot in Paris on 5th April 1884, price 680 Francs. Matte gilt brass movement, bar calibre, 17 jewels, straight-line lever escapement with shepherd’s crook counterpoise, two-arm cut bimetallic compensation balance with tempered steel arm, timing screws, special alloy helical balance spring with inner and outer terminal curves, index regulator. Gold hinged cuvette. White enamel dial with Roman numerals, outer minute track and Arabic five-minute numerals, subsidiary seconds and gold spade hands. Polished case, flat band, the engine-turned back engraved with foliate initials JEM. Cuvette signed, case and movement numbered. Accompanied by a copy of the certificate.
–
Diameter: 51 mm
–
Signed: Louis Audemars Brassus & Genève
–
The high quality of the escapement of this watch with a special alloy helical balance spring suggests that it was intended for the Observatory trial.
–
The Louis Audemars archives confirm that movement No. 13053 appears in the original documents of the Ancienne Maison Louis Audemars et Cie, which traded from 1811 to 1885.