Inventive English gold chronometer chronograph Circa 1866

Unusual chronometer chronograph by Dent
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An unusual and inventive English gold hunting cased keyless pocket chronometer chronograph with regulator type dial, circa 1866. Frosted gilt movement marked ‘Patent’, Earnshaw type spring detent escapement, free-sprung bimetallic compensation balance, spiral balance spring with double overcoil, decoratively engraved balance cock with ruby endstone, chronograph mechanism visible to the backplate. White enamel dial, subsidiary dials for constant seconds to the left and hours to the right, outer minute/chronograph seconds track, three central blued steel hands for constant minutes, chronograph seconds, and chronograph minute recording. 18 Carat gold plain polished case, the front-hinged cover with a monogram, plain snap-on back cover, gold pendant and bow, chronograph push-piece to the band, case hallmarked for London 1866 and with maker’s mark AN for Adolphe Nicole, movement signed Dent Watch Maker to the Queen, 33 Cockspur Street London.
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Diameter: 52 mm
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Signed: Dent Watch Maker to the Queen 33 Cockspur Street London
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Adolphe Nicole was granted a patent for the first English Chronograph where the hands could be reset to zero by a single button. The present watch is an excellent example of the patent. Of further interest is the combination of Chronograph with spring detent escapement.