63,250 CHF
L. Leroy & Cie., 7 Bd. de La Madeleine, Paris,No. 1403, Pendule à pression constante commissioned on January 27th 1930, delivered on December 2, the same year.Very fine and rare, centre seconds, Constant Pressure observatory precision regulator. White painted bronze cylinder with cast-iron white painted wall bracket, glass dome over the brass bracket supporting the movement. Silvered with Arabic seconds ring and observation apertures over the remontoire and the escape wheel. Blued steel counterpoised hand. Brass trapezoidal full plate, marble finished, with cylindrical pillars, running in partial vacuum. Reid type escapement specially adapted by Leroy, the power supplied by the fall of a weighted arm, raised every 32 seconds byan electro-magnet. The invar pendulum beats 61 times in 60 seconds. A double contact is activated directly by the pendulum, and both circuits are closed momentarily with each oscillation, except on the 61st swing when they are by-passed by the action of a third breaker in order to mark the minute. By adjusting the internal pressure of the case, the rate can be adjusted, starting at 0 atmospheres. An increase of pressure of 1 mm of mercury, slows the rate by 0,018 of a second. The rateis adjusted so that the signals coincide with the hour precisely, once the small daily variations have been eliminated.Dim. 146 x 38 cm. Notes Provenance: Commissioned by an important American collector, Mr. D., on January 27, 1930, with the deposit of10'000 Francs,
Auctioneer:
Antiquorum
Date:
1999-10-23
