View your list of saved words. (You can log in using Facebook.)
Mechanical timekeeping device of great accuracy, particularly one used for determining longitude (seelatitude and longitude) at sea. Early weight- and pendulum-driven clocks were inaccurate because of friction and temperature changes and could not be used at sea because of the ship's motion. In 1735 John Harrison invented and constructed the first of four practical marine timekeepers. The modern marine chronometer is suspended to remain horizontal whatever the inclination of the ship and differs in parts of its mechanism from the ordinary watch. A chronometer may provide timekeeping accurate to within 0.1 second per day. See alsoFerdinand Berthoud.
This entry comes from Encyclopædia Britannica Concise. For the full entry on chronometer, visit Britannica.com.