Inventee par Ferdinand Berthoud, circa 1770. Rare and important experimental weight driven journeyman clock, in a fine Louis XVI cabinet. | Important Watches, Wristwatches, Clocks & Jewellery

Important Watches, Wristwatches, Cloc...

Basel April 21, 1990, Apr 21, 1990

LOT 297

Inventee par Ferdinand Berthoud, circa 1770. Rare and important experimental weight driven journeyman clock, in a fine Louis XVI cabinet.

CHF 60,000 - 80,000

Mahogany case with fluted flat columns, glazed on the front and the side panels. Offset sector aperture for the silvered hour volvelle engraved with Roman numerals, subsidiary small silvered dials for minutes and seconds with Arabic numerals.Blued steel hands. Polished brass dial plate engraved with the signature, bearing the second endless rope pulley. Rectangular brass movement with cylindrical pillars, secured by four pins on a thick brass bracket, the Graham pin pallet escapement set on the back plate, gridiron half second beating pendulum with a very fine gimballed knife edge suspension fixed on the bracket plate. In good condition. Dim. 44 x 29 x17 cm.

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Notes

Such regulators were used by Astronomers and scientists for scientific experiments, when they were travel-ling. They were carried with their luggage and therefore had to be built with a short half second beating pendulum, the second endless rope pulley is on the dial plate in order to facilitate the setting up in running order. This regulator is described by Ferdinand Berthoud himself in "De la mesure du temps ou supplement au traite des Horloges marines et a I'Essai sur I'horlogerie", published in 1787, chapter VIII, pages 215 to 228, plate X, and its pendulum in the chapter X, pages 228 to 237, plates IX and X. In the preamble, Berthoud points out that the large long case regulator set with a compensated three feet second beating pendulum are not convenient for a traveller. Therefore, he tried to find a way to built regulator able to keep the time with the same ac-curacy, using a shorter pendulum, such as the half beating pendulum, much easier to be carried than the second beating pendulum.