Very fine Swiss marine chronometer watch Circa 1811

Brass marine chronometer with regulator dial
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A very fine Swiss, two day going marine chronometer à tabatière, with regulator dial. Accompanied by a later mahogany box, circa 1811. Begun in July 1809, finished in January 1811, sold to the Comte de Rosily (for the Department of the Marine) on October 8, 1811. Gilt silver with a glazed bezel secured by two screws fitted in mahogany, three piece, unglazed bezel in the middle part, top with circular ivory plaque, lock between the bottom and the middle parts, sliding brass shuttle in the base panel. White enamel dial by Vincent, eccentric radial Roman hour chapter set at 12 o’clock, centre minutes with five minute Arabic markers, subsidiary seconds. Blued steel Breguet hands.

Brass full plate movement with conical pillars, fusee with Harrison’s maintaining power and chain, very fine train with a high number of teeth and leaves, Earnshaw type spring detent escapement (updated from pivoted detent Louis Berthoud escapement), large Z type bi metallic compensation balance with gold temperature and meantime adjustment screws, blued steel Breguet balance spring updated from three arm balance with conical or cylindrical Louis Berthoud balance spring, jewelled to the third wheel, entire train with steel endplates to reduce friction, balance with jewelled end stones.
Signed on dial and movement.
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Diameter: 84 mm
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Box: 130 x 130 x 80 mm
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Signed: Louis Berthoud (Horloger de la Marine) Swiss
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One of the last large marine chronometers made by Louis Berthoud. Their manufacture in later years was entrusted to Berthoud’s pupils. Louis Berthoud’s work is always unmistakable in its conception as well as in its finish.