French marine chronometer with pivoted detent Circa 1870

Brass chronometer in a mahogany box
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A fine and unusual French marine chronometer in a mahogany box, circa 1870. A four-day going marine chronometer with pivoted detent escapement and power reserve indication. Comes in a mahogany box with a vacant ivory signature plaque. Brass bowl and gimbal suspension. Silvered dial with radial Roman numerals, an outer minute track, subsidiary seconds and an up-and-down scale, polished steel Breguet hands.

Brass movement, two frames with cylindrical pillars, fusee with chain and Harrison’s maintaining power, Henri Robert-type pivoted detent escapement set in a smaller circular cage, two-arm compensation balance with wedge-shaped temperature weights and timing screws, free-sprung blued steel helical balance spring. Dial signed.
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Diameter: 115 mm
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Dimensions box: 180 x 190 x 190 mm
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Signed: M. Viel-Robin Paris
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Although running for four days only, this chronometer is built from an eight-day going chronometer calibre. The pivoted detent escapement is very similar to that devised by Henri Robert in Paris, circa 1830.