20th Century English Marine Chronometer
Inventory Number: C1901001
Made in London circa 1932 by H. Hughes & Son Ltd., fusee movement with spring detent escapement, bimetallic balance, Kullberg style auxiliary compensation. Brass case, gimbal mounted in lacquered brass bowl within two-tier brass bound deck box. Silvered dial with Roman numerals, subsidiary seconds and 56-hour power reserve indicator.
Marine chronometer is a timepiece that is precise and accurate enough to be used as a portable time standard. When sailing, navigators could determine their latitude by measuring the sun's angle at noon, or, in the Northern Hemisphere, to measure the angle of Polaris (the North Star) from the horizon. As the Earth rotates at a regular rate, the time difference between the chronometer and the ship's local time can be used to calculate the longitude of the ship relative to the Greenwich Meridian (defined as 0°).