A LOUIS XVI MAHOGANY MONTH-GOING LONGCASE REGULATOR WITH YEAR CALENDAR AND EQUATION OF TIME

DELUNÉSY À PARIS; THE DIAL SIGNED COTEAU, CIRCA 1780

Details
A LOUIS XVI MAHOGANY MONTH-GOING LONGCASE REGULATOR WITH YEAR CALENDAR AND EQUATION OF TIME
delunésy à paris; the dial signed coteau, circa 1780
The circular white enamel Roman and Arabic dial signed Delunésy à Paris in the center, foliate-pierced and chased gilt-metal mean time arrow minute hands, pierced blued steel arrow-head equation hand and counterpoised blued steel sweep center seconds, calendar apertures between VIII and IX for the revolving white enamel bi-sextile year calendar, the aperture below VI indicating the year calendar with the month, its zodiac and relevant date indicated to by means of a stationary arrow and signed by the dialmaker Coteau, the movement with rectangular plates with four back-pinned pillars, the single weight-driven train with maintaining power to the third wheel, deadbeat escapement with steel pallets and fine adjustment to the crutch-piece for the massive gridiron pendulum made to the design of Ferdinand Berthoud with flat steel and brass rods and offset massive gilt bob oscillating above a white enamel beat scale inscribed Degres du Cercle, the case with detachable dentilled pediment, glazed front door and sides, the rectangular plinth with a raised central panel and on a moulded base
81in. (206cm.) high
Literature
Ferdiand Berthoud, Essai sur l'Horlogerie, 1763, vol. 2, pl. XXXIV, pp. 302-3

Lot Essay

Nicholas-Pierre Délunesy (or Delunery) is recorded at Rue St. Louis 1764, Quays des Grands Augustins, 1772, Rue de l'Arbre Sec, 1781 & Quays des Orfèfres in 1783. Tardy records that Délunesy made a clock for the people of Lyon to give to M. Mortemar, the city's Governor, and that the pendulum was signed by its maker Boizot Fils sculpsit
The present pendulum was designed and probabaly made in the workshops of the great Ferdinand Berthoud, 1727-1807. Berthoud designed this extraordinary gridiron with its off-set bob to avoid any distortion of the bars however he very quickly discovered that the nine-rod grid-iron was more effective (and probably easier to construct) and abandoned this prototype. It is extensively described in his Essai su l'horlogerie, op. cit. and apparently only four were known to exist up until this example was recently discovered; one of the other four is preserved in the Musée national des Techniques, Paris