48,300 HKD
Patek, Philippe & Cie, Genève, No. 170390, case No. 404420, circa 1915.Very fine and rare 18 K gold, hunting cased, keyless, “EXTRA” adjusted watch with special balance and First Class “Bulletin de Marche” with a pair of gold “spade” hands and original mahogany fitted box. Four-body, “deux filets”, polished, gold hinged cuvette. White enamel, Roman numerals, outer minute ring, subsidiary sunk seconds. Blued steel “spade” hands. Notes Superbly adjusted Swiss watches of the period, and particularly those of Patek Philippe ones were signed “EXTRA”.Anibal (acier au nickel pour balanciers), an alloy invented by Dr. Charles Edouard Guillaume, exhibits peculiar properties, both in terms of thermal expansion and in changes in elasticity. In 1899, Guillaume noticed that steel with an addition of 44.4% nickel has a negative square coefficient of thermal expansion. This, combined with brass in bimetallic lamina, makes its expansion close to quadratic. Balances with bimetallic rims made of anibal and brass are usually called Guillaume balances, oras their inventor called them, integral balances. Combined with special balance springs, they show amazing temperature stability, sometimes not exceeding 1/50 second per day per 1ºC.
Auctioneer:
Antiquorum
Date:
2001-06-08
