6,600 CHF
Adjusted Extra & Guillaume Balance Patek, Philippe & Cie. , Genève, No. 109232, case No. 223440. Made in 1898, sold on June 12, 1900. Very fine and rare, 18K rose gold, keyless "Adjusted EXTRA" lever chronometer pocket watch with Guillaume balance, GenevaObservatory Rating Certificate Grade A obtained on November 11, 1899. Accompanied by the Extract from the Archives. Four-body, "bassine", polished, the back cover with engraved monogram. Hinged gold cuvette. White enamel with Breguet numerals, outer minute track, subsidiary seconds dial. Blued steel spade hands. Notes When destined for Observatory Timing Contests, the movements of Patek Philippe watches, like those of other makers, were double-engraved with serial numbers. The inscription "Adjusted Extra" on the bridge of the movement refers to the high finishing of all the parts of the movement. The Guillaume Balance. Anibal acier au nickel pour balanciers, an alloy invented by Dr. Charles Edouard Guillaume, exhibits unusual properties, both in terms of thermal expansion and in changes in elasticity. Around 1900 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 bimetallic balance is approximately a linear function of temperature, while the change of rate caused by change in elasticity of a balance spring is approximately a quadratic function. Thus, it equals zero at only two temperatures, causing secondary error. In
Auctioneer:
Antiquorum
Date:
2008-11-16
