The first planet clocks were made in 1912, constituting round or angular cases with two superimposed dials. The lower dials would usually be crafted from light or dark blue enamel and constantly rotate to represent a day or night sky. Sometimes, a crescent moon in diamonds served as an indicator to the hours at night. The other model that year featured a central disc with a comet that rotated within the dial, while the minutes were read off a pointer that circled along a concentric ring. The auction will offer two such examples lot 11 a semi-mystery clock, circa 1920 (estimate CHF70,000-100,000/US$75,000-110,000) and lot 42 a planet semi-mystery clock, circa 1918, maker Maurice Coüet (estimate: CHF120,000-180,000 US$130,000-190,000). Another very nice example states the obvious: “I do not count the hours, if they are not brilliant”, made in 1913 (estimate: 140,000-200,000).

(L-R) BELLE EPOQUE ENAMEL, EMERALD AND DIAMOND CLOCK, CARTIER
Circular dial with Arabic numerals, purple guilloché enamel, white enamel, emerald beads, rose-cut diamonds monogram, 1910s, mechanical movement, 6.9x5.0x3.7 cm, signed Cartier Paris Londres, no. 2027, red Cartier pouch
Estimate CHF 20,000-30,000, BELLE EPOQUE ENAMEL AND PINK QUARTZ QUARTER REPEATER CLOCK, CARTIER
Purple guilloché enamel, white enamel, cabochon pink quartz, silver (French mark) and gold, mechanical movement, 1907, 7.0x4.8x3.7 cm, signed Cartier Paris Londres, no. 1861, red Cartier original fitted case Estimate CHF 25,000-35,000, ART DECO ENAMEL AND GOLD 'ALTAR' DESK CLOCK, CARTIER Blue and white enamel, blued steel hands, gold, circa 1925, mechanical movement, 4.2x2.3x1.0 cm, signed Cartier, maker's mark (Viel-Robin & Co.), nos. 1939 9300, brown Cartier original fitted case Estimate CHF 15,000-20,000