Transport & space · c. 1040

Magnetic compass

A magnetized needle points north, letting sailors hold a course under cloud.

Song dynasty texts describe a magnetized iron fish for direction finding around 1044, and Shen Kuo described the needle compass in 1088. By the 12th century it was used at sea in both China and Europe. It made open-water navigation possible in any weather.

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

Iron smelting (bloomery) 2000 BCE

What it led to 5

Portolan chart 1275
Carrack 1400
Mariner's astrolabe 1481
Columbian exchange 1492
De Magnete 1600

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