chronometry:<br>the perfect combination of experience and precision.
To earn the right to be called a chronometer, a watch must prove the accuracy of its rate during a standardized testing procedure, and the timepiece’s precision must be certified by an official testing authority. The reason for this elaborate process becomes understandable when one considers the historical background that led to the invention of the chronometer.

As late as the mid-eighteenth century, most mariners were unable to precisely determine their position at sea because they lacked a reliable means of measuring time. This knowledge is essential for the calculation of a ship’s current longitude. Unnecessary detours and seagoing accidents were frequent consequences. This unsatisfactory situation persisted until 1759, when Englishman John Harrison invented the chronometer. Harrison succeeded in constructing a timepiece so accurate that it could be used to calculate the difference between the time at the vessel’s home harbour and the actual time on board, also making it possible to determine longitude. Combined with the known latitude, the two values precisely indicated the vessel’s current position. more...