$2,640
Patek, Philippe & Cie. , Genève, No. 119045, circa 1902, made for the Bailey, Banks and Biddle Co., Philadelphia. Very fine and rare 18K gold keyless pocket chronometer with Guillaume balance. Four-piece, hinged "bassine", polished, cuvette with dedication inscription. hite enamel, Breguet numerals, outer minute track with red five-minute numerals, sunken subsidiary seconds. Pierced and engraved gold Louis XV style hands. Notes Anibal (Acier au NIckel pour BaLanciers) An alloy invented by the Nobel prize winner Dr. Charles Edouard Guillaume, it exhibits unusual properties, both in terms of thermal expansion and in changes in elasticity. These properties are very different from those of two other famous alloys invented by Guillaume, Invar and Elinvar. Around 1900 Guillaume attempted to eliminate the so-calledmiddle 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. Countless attempts were made to eliminate middle temperature error, usually by means of auxiliary compensation devices. In 1899, Guillaume noticed that steel with an addition of 44.4% nickel had a negative square coefficient of thermal expansion. This alloy, combined with brass in bimetallic lamina, makes its exp
Auctioneer:
Antiquorum
Date:
2008-12-11
