In 1878, the largest conical pendulum clock ever built was installed at the Palais du Champ on the occasion of the Paris International Exhibition.
It is a monument with a height of more than 7 meters, consisting of a plinth decorated with bas-reliefs, on each of its four corners there are two-meter bronze caryatids supporting a pyramidal tower. The clock is located in the center, with four dials with a diameter of 125 cm.
A gilded metal ball weighing about 100 kg, representing the earth, with its continents and islands appearing in gilded relief against the blue sea. This ball with the signs of the zodiac is suspended from the center of the dome, 2 meters above the clock and is connected with its invisible movement by a needle. This pendulum rotates under its own weight around an artificial sun at the center of the circle it describes, which extends 15 m. It completes the progression in 10 seconds.
The clock "runs by itself"; the spontaneous waves of this huge pendulum obey natural laws too well known to require explanation; however, some visitors to the exhibition seemed very intrigued and wanted to know where the “little beast is hidden” that drives the entire device.
Aside from remarkable precision, one of the most distinctive characteristics of this watch was the slow, continuous circular motion at a constant speed (instead of the usual swinging motion from side to side) of a silent pendulum tracing a conical path in space, hence its name.