Polish 18 carat gold keyless lever pocket watch Circa 1880

Gold open faced pocket watch
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A Polish 18 carat yellow gold open faced keyless lever pocket watch made by J. Nordt & Sohn, Danzig, circa 1880. Courvoisier’s patented winding and setting system. An engine turned cover and caseback with in the center a circle. Inside the case back, engraved Weihnachten 1878, gilded metal cuvette and gilded brass bow. A white enamel dial with radial Roman numerals, outer minute track, subsidiary seconds at 6 and blued steel hands. A gilt brass movement, going barrel, straight line lever escapement, cut bimetallic compensated balance with gold poising screws and blued steel hairspring with terminal curve, polished steel index regulator, winding and setting wheels mounted on the back plate. The case and dial are signed.
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Diameter: 56 mm
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Weight: 113 g
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Signed: J. Nordt & Sohn  Danzig, Poland
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Accompanied by a copy of the invention patent.
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The movement is based on the British invention patent No. 1 114, delivered on March 26, 1873, to Olivier Courvoisier, Neuchâtel (1, rue du Seyon), for Keyless Watches. In this mechanism, the winding of the barrel is done in the traditional way; the crown is turned clockwise to wind the watch. To set the time, one must push on the pusher (at 11 o’clock) and turn the crown in one direction or the other to set the time. By operating this pushrod, a large steel wheel under the ratchet wheel is moved and engaged with a small steel wheel on the central axis.
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This mechanism was used circa 1875-1880 by the Genevan manufacturer Patek Philippe in some of its watches of 3rd quality. A few examples made by the Fabrique (or Société) genevoise d’ébauches de Montres (Saint Jean) are also known. This company, which won 1st and 2nd prizes at the Geneva horological competition of 1869, went into liquidation in 1880. This mechanism is described in a series of thirteen articles published in the Journal Suisse d’Horlogerie between July 1888 and October 1889. These unsigned pages, of which there is an offprint published in 1889 (82 pp.), are probably by Jean Adrien Philippe (1815-1894), co-founder de Patek Philippe.