$4,140
“Deck Chronometer” Vacheron & Constantin, Genève, “Chronomètre”, No. 455028, case No. 286399. Made for the British Hydrographic Service in 1944. Fine, large, silver, keyless center-seconds deck and pocket lever chronometer with Guillaume balance. Four-body, "bassine", polished, silver, hinged cuvette. Silver, brushed, Arabic numerals, outer minute divisions. Blued steel "spade" hands. Cal. 166, gilt brass, "fausses côtes" decoration, 21 jewels, straight line calibrated lever escapement, anibal-brass Guillaume balance with gold timing screws, blued steel Breguet balance spring, swan-neck micrometric regulator. Dial, case and movement signed, case back engraved “H.S.- 2, 55028”. Diam. 60 mm. Notes Anibal 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-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. Countless attempts were made to eliminate middle temperature error, u
Auctioneer:
Antiquorum
Date:
2005-12-07
