Swiss 18 carat gold open faced keyless lever watch Circa 1899

Gold gentlemen’s watch
–
A very fine and rare Swiss 18 carat gold open faced keyless pocket watch, demi chronomètre, made by Vacheron Constantin SA in Geneva, circa 1899. Gilt brass movement, 20 jewels, wolf’s tooth winding, a straight line moustache lever escapement, large cut bimetallic compensation balance, blued steel Breguet balance spring with overcoil, Brandt’s micrometre regulator. A hinged gold cuvette with inscribed technical details. A solid, polished case, the back with an engraved foliate monogram. White enamel dial with Roman hours, an outer minute track with Arabic five minute numerals, sunk subsidiary seconds at 6 o’clock and gold spade hands. Dial, cuvette and movement signed, case and movement numbered.
–
Diameter: 53 mm
–
Signed: Vacheron & Constantin Genève
–
Henry Capt used the name demi chronomètre to indicate that the movement was sent to the Observatory for chronometric control, but that, for commercial reasons, it did not remain long enough to complete the entire course of testing. It is thought that only two Genevan firms employed the denomination ‘demi chronomètre’: Henry Capt and Vacheron & Constantin.