Thin English 18k gold hunting cased duplex watch Circa 1850

With early Adolphe Nicole patented keyless winding mechanism by Dent
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A very fine and thin English 18 carat gold hunting cased duplex pocket watch with early Adolphe Nicole patented keyless winding mechanism, circa 1850. Frosted gilt 3/4 plate movement, Adolph Nicole’s patent winding system with coasting, duplex escapement, cut bimetallic compensation balance, flat blued steel balance spring, the tail held by a polished steel stud screwed to the cock, foliate engraved cock, index regulator. White enamel dial with narrow painted Roman numerals, outer minute track, large subsidiary seconds at IX and original blued steel Breguet hands. Plain case by Adolph Nicole (master mark), reeded band. Dial and movement signed, movement punched AN/JC, 942, indistinct London hallmarks.
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Diameter: 51 mm
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Signed: E.J. Dent Watchmaker to the Queen London
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The design for stem winding used in this watch is Adolph Nicole’s English patent No. 10348 of October 14, 1844. It pre dates Adrien Philippe’s French Patent of his first winding system by a few months, but Philippe’s system did not require a separate button for the hand setting. Nicole’s patent features a chronograph mechanism and two keyless winding mechanisms, for with fusee and chain and for the mechanism used here. The crown must be rotated clockwise. It can rotate freely when the crown is turned anti clockwise (coasting) so that the hands may be moved forward when the hand setting is engaged. If the hands were to be moved backwards the watch would be wound at the same time. Thus the hands cannot be moved backwards when the watch has been fully wound.