French gold quarter repeating pocket watch Circa 1820

Gold open faced cylinder pocket watch
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A French 18 carat yellow gold quarter repeating keywinding cylinder pocket watch, made by Augustin Merceron in Angoulême, circa 1820. An engine turned case back with a circle in the center. An open faced watch with one horological complication: Quarter repeater by two hammers on two steel gongs, activated by a pull-and-twist piston in the pendant. Silver, engine turned dial with radial Roman numerals, outer minute track, and yellow gold Breguet hands. A gilded brass movement, going barrel, cylinder escapement, monometallic balance and blued steel flat hairspring, blued steel index regulator with temperature-compensating bimetallic curb and parechute, repeater work on the main plate, under the dial. Signature on the cuvette.
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Diameter: 53 mm
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Weight: 78 g
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Signed: Augustin Merceron, Angoulême (France)