Accompanied by Cartier green-leather covered traveling case and a winding and setting key.
Best-known for his "Pendules Mysterieuses" or "Mystery Clocks", Maurice Couet, the twenty-eight year old clockmaker, astonished the industry by exploiting the use of illusion. In his Mystery clocks, first seen in 1913, the hands appear to "float" across the face with no apparent anchor. In reality, they are held in place by transparent discs, usually of rock crystal, citrine or in one instance, aquamarine and driven by gears that are ingeniously hidden in the frame of the case. Captivated by research of 16th, 17th and early 19th century technicians, his workshop produced several variations of the original Mystery clock, each produced over the course of one year and passing through the hands of no less than six or seven specialists - the watchmaker, the designer, the 'orfhvre-bontier', the enameler, the lapidary, the setter, the engraver and the polisher.
Cartier sold the first issue of the "Model A" to J.P. Morgan, Jr. in 1913, at their New York store; this clock recently brought $310,500 at auction. Further, on June 6, 2002 at Christie's Paris, a "Model B" mystery clock, circa 1927, sold for the record price of $372,632. And, for a more recent example sold see Christie's Hong Kong, Important Watches, November 30, 2005, lot 361.
For an almost identical clock see Barracca, Negretti & Nencini, Le Temps de Cartier, p. 99.
See also Nadelhoffer, Thames and Hudson, Cartier: Jewelers Extraordinary, p. 251.