Swiss gold chronograph with pulsometer scale Circa 1920

Gold keyless doctor’s watch
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A very fine 18 carat gold open faced keyless lever pocket watch with chronograph, 30 minute counter and pulsometer scale made by made by Longines in Saint-Imier, Switzerland, circa 1920. The solid, polished case has a hinged gold cuvette engraved with prize medals. White enamel dial with black Roman hours, outer minute and fifth of a second track with red Arabic five minute numerals, an outermost red pulsometer scale graduated to 30 pulsations, subsidiary seconds at 6 o’clock, a 30 minute counter at 12 and pink gold spade hands. Rhodium plated movement with 17 jewels, Geneva Striping decoration, a straight line lever escapement, cut bimetallic compensation balance, Breguet balance spring and an index regulator. Dial inscribed Chronometro Medical, case and movement signed by the watchmaker.
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Diameter: 53.5 mm
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Signed: Longines Saint-Imier Switzerland