Jean André & Jean Baptiste Lepaute, Important Louis XV Ormolu-Mounted Rosewood & Tulipwood Regulator, Month Duration with Sectorial Equation of Time, circa 1760

The movement has Lepaute’s pin wheel escapement, a gridiron pendulum, and employs Huygens continuous rope. The circular chapter ring, which has an aperture below 12 o’clock for the year calendar, has inner Arabic numerals showing mean-time and outer Roman numerals for the hours. Within this is a disc inscribed Tems Vrai (solar time) which rotates showing solar minutes against the gilt minute hand and the equation of time may be read off by noting the difference between the two sets of Arabic numerals. Case attributed to Nicolas Petit (1732-1791), fronted by a solid door with an ormolu-framed glazed cartouche, revealing the pendulum balancier, of elegant transitional style, scrolled acanthus and mask mounts.