The clock’s impressive mechanism, situated at the rear, is visible through the case’s glass backing and in the mirror installed for the purpose.įrom 24 March 2022, under the management of a multidisciplinary scientific committee composed of the most eminent specialists, the Passemant clock will undergo an examination followed by a full restoration of its gilt bronze case – a masterpiece of Rococo art – and its astronomical clock mechanism.The large pendulum, which beats the seconds, has the novel feature of also being able to be used as a natural thermometer, since the difference in dilation between the steel and the copper that make up the clock make it possible to display temperature variations.The revolving disk indicates the phases of the Moon. The date apertures on the front of the case indicate the days of the week, the date, the month and the years (up until 9999, taking into account the leap years).The enamelled clock face with 61 cartouches indicates the hour, the true (solar) minute, the average minute and the second though the movement of the pendulum.It indicates the two equinoxes, the two solstices and the solar and lunar eclipses. We can see the planets’ orbit around the sun – Mercury, Venus, Earth, Moon, Mars, Jupiter, Saturn – their relative positions in the zodiac, and the Moon’s orbit around the Earth. The glass globe that crowns the clock houses the planetary system as seen by Copernicus.After being examined and approved by the French Royal Academy of Science in 1749 and installed in the Palace of Versailles in 1754, the clock was immediately recognised as an extraordinary item.

The construction of the mechanism was entrusted to the clockmaker Louis Dauthiau and the creation of the cabinet in gilt bronze – a masterpiece of rococo art – to Jacques Caffieri.

The clock, which was designed by the mechanical engineer Claude-Siméon Passemant, took nearly 30 years’ to build.

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