English chronometer with Arnold type spring detent escapement Circa 1798

Gold open faced cylinder pocket watch
–
A fine and rare English, 18 carat gold, pocket chronometer with Arnold type spring detent escapement and dead subsidiary seconds, circa 1798. The case with London hallmarks for 1818-1819. A polished, fixed cuvette. White enamel dial, radial Roman numerals, outer minute divisions, subsidiary seconds dial with Arabic four-second numerals. Yellow gold pear hands.
–
A hinged, gilt brass movement, full plate, ringed cylindrical pillars, eight jewels, three in screwed chatons, fusee with chain, Harrison’s maintaining power, Arnold’s spring detent escapement beating 18,000 beats per hour, detent set in a slot cut in the backplate, cut bimetallic compensation balance with internal and external temperature and meantime adjustment screws, free-sprung blued steel helical balance spring with terminal curves, diamond endstone, foliate engraved cock. Dial and movement signed.
–
Diameter: 53 mm
–
Signed: Paul Philip, Barraud   Cornhill, London
–
This watch was supplied by George Jamison (active 1786- 1810) who was one of the makers engaged to supply Barraud with chronometers. Jamison’s association with Barraud ended around 1798 or 1799. This watch was apparently fitted with an upgraded balance in 1818, at which time a new case was also made and a new dial fitted probably because the original was signed Jamison. Provenance: Time Museum, Rockford, Illinois, illustrated and described in their catalogue by Anthony G. Randall pp. 70-71. Paul Philip Barraud. An eminent British maker, in 1796 he entered into a partnership with William Howells and George Jamison, to make chronometers based on Mudge’s original design. Howells, who had been Mudge’s junior worker and had been dismissed, brought with him important technical knowledge. To reduce production costs, they decided to use a single balance spring and Arnold’s Z balance with a helical balance spring.