Exceptional horologic works of art

Hotel Noga Hilton, Geneva, Oct 11, 2003

LOT 218

Louis Berthoud, No. 3, circa 1793. Extremely rare and very fine weight-driven center-seconds wall “Valet Astronomique” regulator.

CHF 80,000 - 100,000

EUR 52,000 - 65,000

Sold: CHF 97,000

C. Mounted to a heavy brass plate with three wall adjustment screws with brass safety nuts, gilt brass circular movement housing, glazed bezel with a brass plate below with applied silver initial “B”. D. White enamel, by master dial-maker Edme-Portail Barbichon, radial Roman numerals, outer minute/seconds divisions with five-minute Arabic markers, winding aperture at 6 o'clock. Gilt brass “Fleur-de-lis” pierced hands. M. Circular, 160 mm, brass, Huygens's endless-rope winding, 4-wheel train, dead-beat Graham escapement set on the back plate, knife edge suspension suspended in a gimbaled brass bracket with hardened steel knife-edge seats, micrometric beat adjustment mounted on the crutch, iron-brass gridiron compensation pendulum with heavy brass bob and micrometric adjustment nut, brass pulley with Harrison's maintaining power.Signed on dial and movement, in addition the dial signed by Barbichon.Dim. 26 x 21 cm (mounting plate),housing diam. 19 cm.


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Grading System
Grade:
Case: 3

Good
Movement: 3*

Good

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

Notes

This is the previously unrecorded duodecimal companion to Berthoud's decimal “Valet Astronomique” No. 2, made for the Paris Observatory in 1792. It is virtually the same except for the dial, which in the Paris Observatory is calibrated for the decimal system. This clock required considerable experimentation on Berthoud's part. He received the commission with a 500 livre advance on May 1, 1792. It is last mentioned in his journal on February 17, 1794. On January 4, 1794 he wrote, concerning the dial:“I shall mark the minutes around the circumference which will serve at the same time for the seconds, the hours will be inside”. The clock was delivered to the Observatory either in 1795 or 1796. It appears that the design was so successful that Berthoud made one more, exactly the same the present one, possibly for a scientific institution outside the French Republic. “Valet Astronomiques” were built for scientific and surveying purposes. They were constructed so that just the movement with its heavy bracket could be traveled with and placed almost anywhere. For this reason they were extremely well and solidly made; some had carrying cabinets.Literature: J.-C. Sabrier in “La Longitude en mer à l'heure de Louis Berthoud et de Henri Motel”, Antiquorum Editions, Geneva, 1993, pp.153-155, 163.