Technically interesting Swiss gold chronograph Circa 1860

Gold chronograph with stoppable independent seconds
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An early and technically interesting Swiss 18 carat gold open faced independent seconds and jumping ¼ second chronograph, circa 1860. Bridge movement, gold wheels, special lever, two barrels, one for the movement and one for the stoppable independent seconds, releasing and stopping of the seconds and the flashing ¼ second by pushing the crown. White enamel dial with Roman hours and Arabic five minutes, chronograph register, extraordinary gold and blued steel hands. Plain case.
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Diameter: 51.5 mm
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weight: 90 g
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Signed: No name
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This version with a double complication is extremely rare. Normally, the releasing and stopping is done by a pusher on the band of the case.