DESCRIPTION:
Synchronome Co. Ltd., London, a Shortt- Synchronome sidereal free pendulum master clock with slave, the master with invar pendulum rod, cylindrical bob and brass compensation sleeve, housed in a cylindrical copper vacuum tank with integral mounting brackets, evacuation valve at the base, and instrument cluster for monitoring temperature and pressure inside the tank, the top with heavy bell jar, plate glass bottom allowing viewing of the beat scale attached to the bottom of the pendulum, heavy cast brass four legged frame suspending the pendulum and movement, the movement with damascened, lacquered brass plates and bridges, receiving electrical impulse from the slave, which in turn drops a gravity arm to periodically impulse the pendulum, the slave with rectangular mahogany case having a molded top and base, silvered astronomical dial signed "Synchronome London", the movement with " hit and miss synchronizer", cast backplate and lacquered brass components, pendulum rod with cylindrical bob, and beat scale mounted to a canted oak block, together with original factory nameplates, vacuum sealing grease, and fine regulation weights. Purchased by the consignor at Dunning's Auction, Elgin Illinois, Collection of Clifford Haumiller, 11/1/87, lot 117.
CONDITION:
Master and slave functioning at time of consignment, copper tank with tarnish, bottom glass with minor chips, movement, impulse wheel carriage and suspension block in old lacquer, four legged frame polished and in newer lacquer, front left leg with abrasion, thermometer and barometer good, beat scale and mirror good, pendulum with letter S crudely punched into bottom of bob, suspension spring replaced, and not in the Shortt style, master pendulum impulse wheel with minor flat, two screws replaced and one missing in each of the pendulum safety mounts, slave case moldings with separation at joints, shrinkage has left a gap in the case top, door and left side with warp, door with gap when closed, two catches added to left side to secure door, upper lock latch plate detached but present, minor losses to finish, pendulum bob with minor abrasions, gathering wire replaced, gathering jewel made from a piece of plastic wire insulation. The Shortt free pendulum clock was the standard for precision timekeeping from the early 1920's until about 1950, when it was surpassed by the quartz oscillator. In 1926, the clock confirmed tiny seasonal changes in the rotation of the earth, and was the first timekeeper more accurate than earth itself. A Shortt clock at the U.S. Naval Observatory was studied in the mid 1980's, using modern equipment to measure it's accuracy; the clock was found to be stable to within .002 seconds per day, the equivalent of one second in twelve years. The study also confirmed that the clock was sensitive enough to detect changes in gravity due to tidal distortion of the earth caused by the gravitational pull of the sun and moon.
ESTIMATE:
$60000
-
$80000
PRICE SOLD:
$90000
CIRCA: 1928--1950
DIMENSIONS: 55.25in x 16in x 8in
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