Double-Cased Thomas Mercer Marine Chronometer,
ca 1950, a two-day (56-hour) marine chronometer by Thomas Mercer, Ltd. London. Cast brass bowl with threaded glazed bezel gimbaled in two-body mahogany box with glazed panel in the top under a hinged lid with a catch, gimbal ring locked by a swiveling arm pressing sideways against the base of the cylinder, and two-body mahogany outer carrying box. Silvered dial with Arabic hour numerals, outer minute ring, Arabic seconds on subsidiary dial at 6 o'clock, up/down wind indicator at 12 o'clock. Blued steel "Spade" hands. Gilt brass full plate with recess for the mainspring barrel, circular pillars secured by screws, fusee and chain, 13 jewels, detachable Earnshaw spring-detent escapement, bimetallic ovalizing Volet compensation balance with free-sprung helical balance spring with terminal curves, four cylindrical temperature adjustment weights, two mean time adjustment nuts, jeweled to the third wheel. Signed on the dial Thomas Mercer Ltd / St. Albans England and with serial number 21530. Inner case is 7.5" square x 7" high; outer case is 9.5" square x 8" high. Breguet-type key included. Condition report Normal wear, carry strap missing; currently running, however, we do not guarantee working order of clocks and watches.
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