Appearing in the mid-18th century, ‘mystery clocks’ were designed to indicate the time but also to fascinate and surprise. Making full use of ornamental sculpture, their makers devised ingenious subterfuges to conceal their workings. Like the one on display in the Musée des Arts et Métiers, awarded a prize at the 1889 Universal Exposition, mystery clocks were often mechanical masterpieces in their own right. A gilt bronze statuette is holding what appears to be a pendulum. Yet despite its apparent immobility, the clock is indeed working. The mechanism is discreetly driven by the imperceptible rotation of the statue’s base.