Marine chronometer
Cronómetro marino
- Date
- 1735 (H1) / 1759 (H4) · confidence high
- Place
- Barrow upon Humber / London, England
- Credited to
- John Harrison
- People
- 👤 John Harrison1693–1776
- Field
- Movement
What it is
A high-precision, temperature-compensated clock with a lubrication-free escapement, keeping the time of a reference meridian at sea in order to calculate longitude. The H1 (1735) demonstrated the principle, and the H4 (1759) won the prize under the Longitude Act (1714).
The rival lunar-distance method (Maskelyne, Mayer) competed with it until chronometers became cheaper. Merged with «Marine chronometer (H4)» (duplicate, 23 September 2026).
What it led to
- The solution of the longitude problem and safe oceanic navigation
- Precise global cartography (Cook, Vancouver)
- The Greenwich meridian as a world reference
- The English precision watchmaking industry
- Safe oceanic navigation and precise cartography (Cook)
- British maritime trade and empire
- The serial production of chronometers (Arnold, Earnshaw) and Greenwich as the reference meridian
- Precision watchmaking
Built on
- Pocket watchc. 1510
- Pendulum clock1656
- Wheel-cutting enginec. 1670-1700
- Balance spring (hairspring)1675
- Longitude Act and Board of Longitude1714
- Lunar distance method and the Nautical Almanac1763-1767
- Grasshopper escapement
- Gridiron compensation pendulum (Harrison, 1725)
- Harrison's H1-H3 clocks
- Anchor escapement
Made possible
- Greenwich Meridian as the prime meridian1851-1884
- Arnold and Earnshaw chronometers (series production)
- Admiralty charts
- Time zone system
- Arnold and Earnshaw chronometers
- Accurate nautical charts