The Longitude at the Eve of the Third...

Geneva, Hotel Des Bergues, Oct 23, 1999

LOT 32

Auguste Berthoud, No. 178, circa 1840.Fine and probably unique mahogany experimental marine chronometer en forme de tabatière.

CHF 30,000 - 35,000

C. Double body mahogany box with slide on the lid over the observation aperture. Brass gimball with a ladded bowl. Brass case en forme de tabatière, similar to that used by Louis Berthoud for his later chronometer. D. Silvered regulator type, similar to that used by Louis Berthoud, with small Roman chapter ring for hours, subsidiary seconds below, outer Arabic minute ring on the border of the bezel. Blued steel Breguet hands. M. Brass, full plate with steel conical pillars secured by nuts with wshers. Fusee with chain, maintaining power, spring detent escapement, three-arm compensation balance, with three wedged weights and timing screws, blued steel helical balance spring.Signed on the dial.Dial diam. 80 mm.Dim. 14 x 16 x 16 cm.


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Grading System
Grade: AAA

Excellent
Case: 3

Good
Movement: * 4 - 6
Dial: 4 - 5 - 01

Notes

Although it is similar to most of the other marine chronometers made by Charles-Auguste Berthoud, this chronometer was fitted with a spring detent escapement in place of the usual pivoted detent, similar to that made by his father Louis Berthoud. The back plate was pierced to allow one to see the functions of this unusual spring detent escapement.No other chronometer by this maker, fitted with a spring detent escapement is known to exist.