17,825 CHF
Pierre Rousseau à Paris, circa 1700. Extremely rare silver Louis XIV "oignon" with " pirouette" escapement. Double body, oignon, fully engraved with scrolled foliage. Hinged gilt brass full plate with Egyptian pillars, fusee with chain, verge escapement with "pirouette".Plain three-arm steel balance, flat balance spring and gilt brass Louis XIV cock pierced and engraved with inhabited foliage. Rack and pinion regulator with delicate pierced blued-steel brackets. Signed on the back plate. In good condition. Diam. 57 mm. Notes Probably Pierre Rousseau of Pithiviers and subsequently Paris, who was the brother of André, (see lot 30), and married in 1705. 'Oignons' front the period of Louis XIV with a pirouette escapement are exceptionally rare. They are constructed on the principle of the very earliest watches to he made with balance-springs, and indeed, Huygens had in effect imagined this device to increase the amplitude of the balance which he considered to be too small. In operation, the verge staff carries not only the pallets, which engage the crown wheel in the conventional way, but also a wheel which engages a pinion on the balance staff; in effect the arc of the balance is greatly increased, and the watch appears to beat more slowly. However, the supplementary gearing for the 'pirouette' has a tendancy to increase the frictional losses and any intended gains are therefore likely to be cancelled out. Huygens quickly abandoned this stratagem, and needless to
Auctioneer:
Antiquorum
Date:
1993-11-14
