The first Mystery Clock was the result of the collaboration between Louis Cartier and the technical skill of Maurice Couët, developed after the study of the work of Robert Houdin, the French magician and clockmaker (1805-1871). Based on the principle of an optical illusion, the mystery is in the hands that appear to float in space without any connection to the movement, when, in fact, each is fixed onto a separate crystal disc. These discs are surrounded by a tooth-edged border and driven by a spiral fixed at the end of the two lateral axles, working a the levels of 9 and 3 o'clock, concealed within the frame. The rotation of the axles is activated by the movement hidden in the base. Therefore, it is not actually the hands which rotate at different speeds for minutes and hours, but the dics on which the hands are individually fixed.

The 'Mysterieuse' illusion of lot 327 is executed with exceptional skill as both technically and visually the transmission from the base to the dial is completely concealed. However, the pure geometric style is more akin to the work of Mauboussin than the style of Cartier.