Swiss gold tourbillon with chronometer escapement Circa 1845

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A gentleman’s remarkable pocket watch with tourbillon and pivoted detent escapement by Frédéric Alexandre Courvoisier, circa 1845. Later custom-made case by Richard Daners, Lucerne. 18k gold case, engine turned, hand engraved edges, engraved gold dome. “tourbillon, frederic courvoisier, nr 19442, boite par R. daners, Lucerne, 1985” case maker’s punch mark “RD” Dial is silvered, radial Roman hours, auxiliary seconds, signed,  blue steel hands, florally engraved, applied foliate gold ornaments, 3/4 plate movement, keywind, frosted, gilt, signed, screwed chatons, 16 jewels,  gold screw chronometer balance, blued balance spring, florally engraved balance cock, chain/fusee, finest mirror polished tourbillon steel cage, tourbillon with 1 minute rotation time, pivoted detent escapment
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Diameter: 56 mm