Lot 207

Ferdinand Berthoud à Paris, Height 1200 mm, circa 1770
A rare precision regulator with 9-rod grid-iron pendulum
Dial: enamel. Movm.: circular brass plate movement, Graham escapement, brass pendulum bob, heavy brass gimbals for pendulum spring suspension with two springs.
In Vol. 2 of his series on precision pendulum clocks Jürgen Ermert writes on the "French observatory clocks":
"These master clocks are nearly identical in design and were produced over a long period according to the specifications stipulated by the observatories. Technical literature by Erbrich and Roberts records this type of clock as having been produced by Ferdinand Berthoud in Paris (1762), Louis Berthoud, Breguet, Jean Francois Henry Motel and Simon Vissiere (circa1870).
The enamel dials used for these clocks usually have a relatively small diameter (circa 160-210 mm) and are designed according to the specifications of the academy of sciences; the clock unit comes in a dust-proof brass cylinder, with a solid movement plate and all the other typical features of a high precision clock that is intended for scientific purposes. The system was usually delivered to the customer without case. The indications for seconds, minutes and hours sit in the centre; the unit with the movement is then fitted on the plate with the pendulum already suspended. The opening for the fork and the pendulum is visible at the bottom end of the cylinder. With a few exceptions, these clocks usually feature a Graham escapement, a one month power reserve and a gridiron pendulum. Sometimes the anchor was fitted on the outside of the back plate. Even though stones were already in use for high quality clocks by 1800, the majority of the clocks had the usual brass bearings. The stone pallets on the anchor also came later."
This description matches our clock very well, even though it has a larger, 25 cm dial, which was created by Dubuisson; Dubuisson was one of the most famous enamellers of his time.
Even as a young man Ferdinand Berthoud’s skills were so outstanding that they drew the attention of Julien Le Roy; the two men worked together for a long time. Around 1745 Berthoud opened a workshop in the Rue Harlay and from 1756 on specialised on precision watches; in 1771 he invented the pivoted detent escapement chronometer escapement. It is likely that Abraham Louis Breguet also worked for Berthoud. Berthoud was purveryor to the court of King Louis XV as well as that of his grandson and successor Louis XVI.
In 1763 and 1766 Berthoud was sent to London to discover the workings of Harrison’s H4. He achieved fame for producing the French marine chronometer; in 1770 he was awarded the position of "Horloger mécanicien du Roi et de la Marine" (watchmaker to the king and the navy) He later became a member of the "Institut de France" and the "Royal Society". On July 17, 1804 Ferdinand Berthoud was made a Knight of the Legion of Honour; he died without issue after a short illness on June 20, 1897 in Groslay near Paris. He has a primary school in Paris named after him as well as streets in Couvet, Argenteuil, Groslay and Besançon.