English silver historical chronometer pocket watch Circa 1797

Silver open faced pocket watch by John Arnold & Son
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An English pocket chronometer of historical interest out of Arnold’s series III with Arnold’s spring detent escapement, manufactured in quality II, circa 1797.
A silver polished case, little engraving, hallmark London 1810, case maker’s punch mark DW (Daniel Walker, New Shore Buildings, Clerkenwell Close). White enamel dial with radial Roman numerals, outer minutes track, subsidiary dial for the seconds, and gold Breguet hands. Full plate movement, chain/fusee, keywind, gold screw compensation balance according to Pennington.
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Diameter: 54 mm
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Weight: 154 g
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Signed: John Arnold & Son, London, Invt. et Fecit
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This chronometer was originally built in 1797 and had most likely been fitted with John Arnold’s Z balance; in1810; however, it was remodelled by John-Roger Arnold. A new case was ordered from Daniel Walker, who had already created a number of pieces for J.R. Arnold. The watch was also fitted with a more modern dial, while the original set of hands was kept. Likewise, J.R. Arnold obviously decided to keep the original spring detent escapement, but he fitted the movement with a Pennington balance which was quite a novelty at the time. Here an extra heavy and high-quality version of the balance was used. All in all, this is a fascinating pocket chronometer that shows the gradual development of the technology used by Arnold’s son John Roger Arnold in the course of the modernization process.