13,225 CHF
Patek, Philippe & Cie. , Genève, No. 146830, case No. 258492, made for Henry Kohn & Sons, circa 1906.Very fine 18K gold keyless "EXTRA" adjusted pocket chronometer with special balance, obtained the third prize in the 1909 and 1910 Geneva Astronomical Observatory Contest. Accompanied by original Patek Philippe certificate. Four-body, "bassine", polished, gold hinged cuvette. White enamel, Breguet numerals, outer minute ring, with five minute red Arabic markers, subsidiary sunk seconds. Gold "Louis XV" hands. 41,27 mm, nickel, "fausses côtes" decoration, 20 jewels, straight line calibrated lever escapement, cut bimetallic compensation balance, blued steel Breguet balance-spring, Guillaume balance with diamond endstone, "swan-neck" micrometric regulator.Signed on dial, case and movement, movement stamped twice with the serial number.Diam. 50 mm. Notes Superbly adjusted Swiss watches of the period, and particularly those of Patek Philippe, were signed "EXTRA" or "SPECIAL".Guillaume balanceAnibal (acier au nickel pour balanciers), an alloy invented by Dr. Charles Edouard Guillaume, exhibits unusual properties, both in terms of thermal expansion and changes in elasticity. These properties are very different from those of two other famous alloys invented by Guillaume, Invar and Elinvar. At the end of the 1800's, Guillaume attempted to eliminate the so-called Middle Temperature Error caused by the fact that the change of rate in a timekeeper with a steel-brass bi
Auctioneer:
Antiquorum
Date:
2001-10-13
