Thematic Auction in Geneva:The Evolut...

Hotel Noga Hilton, Geneva, Nov 16, 2002

LOT 50

Breguet, Paris, No. 3290, circa 1935.Very fine two-tone 18K gold and silver keyless lever pocket chronometer winner of gold medal and Bulletin de Premiere Classe in Besançon, with original gold medal and original Bulletin de Marche.

CHF 15,000 - 20,000

EUR 10,000 - 14,000

Sold: CHF 17,250

C. Four-body, "Empire", polished with reeded band, bezels with silver edges, gold hinged cuvette, silver bow. D. Silver, engine-turned center and outer border, champlevé radial Roman numerals, outer minute dot divisions, subsidiary seconds. Blued steel Breguet hands. M. 44 mm. (19 1/2'''), rhodium-plated, "fausses côtes" decoration, 19 jewels, straight line lever escapement, Guillaume anibal-brass cut bimetallic compensation balance, Breguet balance spring, wolf-tooth winding wheels, viper's heapunch mark.Signed on dial, case and movement.Diam. 52 mm.


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Grading System
Grade: AAA

Excellent

Case: 3

Good

Movement: 3*

Good

Overhaul recommended, at buyer's expense

Dial: 3 - 01

Notes

The viper's head was the official Besançon Observatory hallmark, acknowledging the fact that the watch took part in one of their timing contests.Results of the Bulletin de Marche: Maximum average variation + 2.01 Variation between horizontal and vertical positions - 0.82 Average daily error ± 0.218 Average positional error ± 68 Temperature compensation error for 1oC + 0.09 Restart - 1.96It is very rare to find a watch accompanied by its original papers, box and medal.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. 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 bimetallic balance is ap-proximately a linear function of temprature, while the change of rate caused by change in elasticity of a balance spring is approxi-mately a quadratic function. Thus, it equals zero at only two tem-peratures, causing secondary error. Countless attempts were made to eliminate Middle Temperature Error, usually by means of aux-iliary 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, mkes its expansion close to quadratic. Balances with bi-metallic rims made of anibal and brass are usually called Guillaume balances, or, as their inventor called them, integral balances. When combined with special balance springs, they exhibit remarkable temperature stability, on occasion not exceeding 1/50 second per day at 1oC.