204,250 CHF
Ferdinand Berthoud à Paris, circa 1770. Very fine and rare, month-going rose wood marquetry, weight-driven longcase regulator with equation of time. White enamel by Coteau with Roman numerals, outer Arabic minute ring, gold paillonne five minute divisions, aperture below "XII" for the annual calendar. Pierced and engraved gilt brass hands with blued-steel centre- seconds and mean time minute hand. Notes Invented by Ferdinand Berthoud, the pendulum of this regulator is described in his Essai sur l' Horlogerie, 1763, vol. 2, pl. XXXIV, pp. 302 and 303. It is constructed from three bars only, two of steel, one in brass. In order to perfect the compensation, F. Berthoud devised an auxiliary adjustable compensation lever ("L" on the design), mounted between the bar of brass and one of the steel bars. The pendulum is also fitted with a thermometer. The bob is offset relative to the centre line of the pendulum, apparently to avoid any distortion of the bars. At rest, the gridiron is therefore at an angle from the vertical. This type of pendulum was soon abandoned in favour of the 9 rod gril-iron pendulum. To date, only four regulators, including this lot, fitted with this form of pendulum are known, one of which is preserved in the Musée National des Techniques (C.N.A.M.), Paris. Jean Martin Jean Martin was related to some trusted servants of Berthoud at Groslay to whom he left a bequest in his will. When he retired to his house of Groslay in 1779, to write his books and
Auctioneer:
Antiquorum
Date:
1993-11-14
