English silver chronometer with duplex escapement Circa 1820

Silver open faced pocket watch by John Barwise
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A rare English pocket chronometer with duplex escapement and unusual calibre, circa 1820. Silver case with case maker’s punch mark JW (Joseph Walton), London date letter for 1889. Frosted movement with gilt chain/fusee, duplex escapement, screw compensation balance, blued balance spring and chatoned diamond endstone on balance. Signed enamel dial with radial Roman hours, auxiliary seconds and gold Breguet hands.
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Diameter: 53 mm
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Weight: 114 g
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Signed: John Barwise, London
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John Barwise (1757-1842) Barwise was one of London’s most renowned makers of precision watches and one of the few watchmakers who served as an expert on the Board of Longitude during the chronometer dispute between John Arnold and Thomas Earnshaw.