Transport & space · 1761

Marine chronometer

Harrison's sea clock keeps time well enough to solve longitude.

John Harrison's H4 lost only 5 seconds on an 81-day voyage to Jamaica in 1761-62. Comparing local noon to a precise home-port time gives longitude, the great unsolved navigation problem. Chronometers became standard on ships by the early 19th century.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

Mechanical clock 1280

What it led to 1

Clipper ship 1845

Related measurements

The dashed line marks when it first worked.

Transatlantic crossing time Latest: 3.5 hours (1976) Source: Wikipedia: Transatlantic crossing, duration list; Geography of Transport Systems: liner transatlantic crossing times

World trade as a share of GDP since 1500 Latest: 1950-now (PWT): 57.8 % of GDP (2023) Source: Our World in Data