Important French gold double dialed pocket watch Circa 1770

Gold watch with special escapement
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An extremely fine and important French 18 Carat gold pocket watch, circa 1770. Two time zone double dialed pocket watch with mock pendulum and slow beat frictional rest escapement with a pirouette. Louis XV, engraved bezels, both sides glazed. Meantime dial: White enamel with radial Roman numerals, outer minute track and Arabic five minute numerals, winding aperture at 12 o’clock, secured by a screw. Gold beetle and poker hands. Reverse dial: Small, eccentric, white enamel with radial Roman numerals, outer minute track and Arabic five minute numerals, border of finely chased vari coloured gold leaf swags above four pillars and a vase of flowers, engraved gold, mirror polished and blued steel background, aperture for the mock pendulum below.

Gilt brass movement, full plate, conical pillars, going barrel, frictional rest escapement, the escape wheel with “C” shaped teeth, steel balance staff mounted with the counterpoised mock pendulum arm, inverted three arm balance wheel mounted between the dial and front plate with toothed rim geared to the three arm brass pirouette wheel, blued steel flat balance spring, index regulator lever in the dial-plate. Dial signed.
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Diameter: 43 mm
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Signed: Marcinhes Paris
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This extremely rare and ingenious watch is both mechanically fascinating and extremely decorative. Each dial can be set independently without disturbing the other dial, though both are driven by the same gearing. This is achieved due to the central pinion being friction fitted so that the power from the going barrel is sufficient to drive the gearing but allows enough slip so that when the hands are set on one side, the hands on the other side do not move during setting. The escapement is highly unusual and very rare, it is a frictional rest escapement with a large escape wheel with “C” shaped teeth at right angles to the wheel and acting against a steel staff. In operation it is not unlike the action of a cylinder escapement. The balance wheel itself has a toothed periphery which drives the pirouette wheel pinion. Slow beating watches such as the present watch and those made by Pouzait slightly later were perhaps partly inspired by the desire to make the watches appear to have more accurate timekeeping abilities. Discerning buyers were used to seeing regulator clocks with deadbeat or pin wheel escapements and slow beating pendulums so that the watchmaker would have presented a watch of this type as something special and sophisticated. Pierre-François Marcinhes (1739-1778) Of Genevan origin, son of the engraver Jean-Philippe, he was apprenticed to Jean-Pierre Soubeyran in 1753.