Musées de Langres – Maison des Lumières Denis Diderot – Musée d'Art et d'Histoire

The plaque inside the lid of the box indicates that the chronometer was made by “James Hatton, CHRONOMETER MAKER to the Hon(oura)ble the EAST INDIA COMPANY, St Michaels Alley, Cornhill, LONDON”. The dial bears the manufacturer’s signature and the item’s serial number (400).

The marine chronometer was a significant18^th-century breakthrough because it made precise timekeeping possible on long sea voyages. In combination with a sextant, the chronometer allowed seafarers to calculate a ship’s longitude, which they could not do before. The marine chronometer was invented and gradually perfected by the English watchmaker John Harrison (1693–1776) between 1736 and 1759. Chronometers were commonly used on ships between 1770 and 1780. The use of chronometers at sea became widespread in the 1770s.