19,550 CHF
Riefler, Münich, No. 2062, circa 1900. Very fine and rare mahogany wall regulator beating seconds, with regulator dial, invar pendulum and barometric pressure compensation. Rectangular, glazed on both sides and front, molded top, hinged glazed doors on both sides of the movement Rectangular, brass, long duration by means of double pulley, Graham escapement with specially hardened steel pallets, spring suspension, invar rod pendulum with invar rod and pressure compensation attachment, micrometric length adjusting nut serving also as temperature compensation, micrometric beat adjustment on the crutch.Signed on the pendulum.Dim. Height 142 cm. Notes Invar's coefficient of expansion is about twelve times lower than steel. Therefore it needs very little compensation. The slight expansion of the pendulum rod is compensated by a nut made of steel or nickel. When the temperature rises, it very slightly lifts the bob to the exact extent to which the pendulum expanded downward. The center of gravity remains the same. In addition to temperature, air pressure also affects the oscillation time of a pendulum. Under rising air pressure, the pendulum swings more slowly, and speeds up under falling pressure. To compensate for this Riefler invented a special device (German patent No. 100870) consisting of a five-box aneroid and weight to compensate for changes in air pressure.
Auctioneer:
Antiquorum
Date:
2003-10-11
