L\'ART DE L\'HORLOGERIE EN FRANCE DE ...
Geneva, Hotel Des Bergues, Nov 14, 1993
Julien Le Roy à Paris, Invenit et Fecit, No. 4732, made by his son Pierre, circa 1774. Extremely rare and important movement of a centre-seconds watch, so called "Petite Ronde", divised by Pierre Le Roy à l'usage des astronomes et des marins.
D. Later white enamel with Roman numerals and outer Arabic minute ring. Gold Louis XV hands. M. Gilt brass full plate with cylindrical pillars, fusee with chain, frictional rest escapement of Sully type, improved by Pierre Le Roy, with the typical "spider" escape wheel, three-arm balance with gold studs, flat balance spring regulation with unusual index, small cock with one foot only and ruby end-stone. The traces of a compensation device reveal the system devised by Pierre Le Roy for this timekeeper which evidently belongs to the very rare group of the so called La Petite Ronde, intended for use at sea. The bimetallic compensation consists of two blades acting through ail arm upon the regulating index. In good condition.