A mystery watch or mystery clock, in horology, is a timepiece whose working is not easily deducible, because it seems to have no movement at all, or the hands do not seem to be connected to any movement.
[1] One example is a type of mechanical watch where the movement is transmitted to the hands through a transparent crystal toothed wheel.
[3] Rime's watch was marketed by the French firm Armand Schwob et frère, and made in Switzerland.
It has also been said that Jean-Eugène Robert-Houdin was the inventor of the mystery watch in the 19th century.
Robert-Houdin was a watchmaker, like his father, and later became a magician.