Important Modern & Vintage Timepieces

Geneva, Nov 10, 2013

LOT 527

TAVAN - IMPORTANT SILVER PORTABLE ONE-DAY MARINE CHRONOMETER WITH SPECIAL CONSTANT FORCE ESCAPEMENT INVENTED BY TAVAN Antoine Tavan, à Geneve, Invenit & Fecit. Made for marine navigation, circa 1819. Very fine, extremely rare and important, large, silver-cased by Amy Gros, 1-day going portable precision Chronometer marine timekeeper with 'OZ' type balance, constant force escapement of unusual construction with remontoire and stop feature for exact setting. Probably the marine timekeeper by Tavan with constant force escapement which achieved First Prize at the Concours de Chronométrie de L'Observatoire de Genève in 1819.

CHF 20,000 - 30,000

HKD 165,000 - 250,000 / USD 21,000 - 32,000

Sold: CHF 25,000

Three-body, silver, 'bassine et collier' by Amy Gros with deep back, tapered band, ball-form pendant with circular bow, hinged back with shuttered winding aperture. Gilt- brass dust ring secured by three screws, hinged cuvette fixed to the dust ring. White enamel, radial Roman numerals, outer minute divisions with Arabic five-minute numerals, large subsidiary seconds with Arabic five-second numerals. Fine gold beetle and poker hands. 68 mm., matte gilt, full plate, cylindrical pillars with flared ends, fusee and chain with Harrison's maintaining power, steel stopwork on the dial plate, jeweled Chronometer escapement mounted on a separate subsidiary plate within the movement, with steel escape wheel, the upper pivot jewels with polished steel plates, pivoted anchor with jeweled entry pallets, the fork at the opposing end engaging with the locking jewel on the balance staff, a further separately pivoted lever with single jeweled pallet for the exit engaging with a roller on the balance staff, this lever is impulsed by a spiral remontoire spring placed at the upper end of it's pivot and providing a constant force to the escapement, four-arm bimetallic `OZ` balance with jeweled pivots, meantime adjustment screws and segmental brass temperature weights with polished steel caps, free-sprung blued steel helical balance spring with inner and outer terminal curves, the balance held with a large shaped and pierced brass plate with four pillars on the backplate.


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Grading System
Grade:
Case: 3

Good
Movement: 2*

Very good

Overhaul recommended, at buyer's expense
Dial: 3-8-01

Good

Slightly scratched

HANDS Original

Notes

Dial and cuvette signed, case punched 'Gros'. DIAM. 82 mm. This watch is almost certainly the same one that won First Prize at the Geneva Observatory Chronometer Timing Contest in 1819 and incorporates the constant force Chronometer escapement of Antoine Tavan's invention. It is most likely his masterpiece, certainly an extremely rare survival and an important timekeeper in the history of horology. In France and Switzerland, the technical advances in timekeepers for marine navigation occurred more or less simultaneously with those being developed in England and by the end of the 18th century the detent escapement had already been invented. In France and Switzerland however, no standard form of marine timekeeper seems to have been made, each maker preferring his own particular form of construction. This resulted in quite a number of different calibers including the present watch which uses a system of two jeweled pivoted levers