Swiss gold open faced keyless lever chronograph Circa 1905

Gold chronograph instantaneous 30 minute register with by Longines
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A very fine, Swiss 18 carat gold open faced keyless lever chronograph pocket watch with instantaneous 30 minute register, circa 1905. Frosted gilt movement, 19 jewels, straight-line lever escapement, cut bimetallic compensation balance with gold adjusting screws, blued steel Breguet balance spring with overcoil, Wilmot’s patent micrometer cam regulator, chronograph work on the back plate activated by a coaxial button in the crown. Gold hinged cuvette with engraved dedication. White enamel dial with bold painted Arabic numerals, outer minute and fifths of a second chronograph divisions, Arabic five minute/seconds numerals, subsidiary dials for the seconds and instantaneous 30 minute register, original gilt Louis XV hands. Matte, cast and chased case with the arms of Bern in high relief and the inscription Feuer Wehr, Bern, chased foliate and floral bezels and band, foliate cast bow. Dial and movement signed, case numbered. Accompanied by a box.
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Diameter: 52 mm
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Signed: Longines