Longitude
Summary
Hosted by John Hopkins, this episode explores the historical crisis of calculating longitude at sea, illustrated by the 1707 Scilly naval disaster. It details the rivalry between astronomical methods and clockmaker John Harrison’s marine chronometer, which ultimately solved the problem. The narrative concludes with the establishment of the Greenwich Prime Meridian and the evolution to modern satellite navigation.
Topics discussed
Sponsors: Progressive and Indeed
The Scilly naval disaster of 1707
The problem of longitude vs latitude
Dead reckoning and the need for time
Rising stakes for global trade and empire
Early celestial solutions: Jupiter's moons
The lunar distance method and astronomical tables
The Longitude Act of 1714
John Harrison's early innovations
Harrison's H1, H2, and H3 sea clocks
The creation of the H4 marine chronometer
The successful trial to Jamaica
Political disputes and the lunar method rivalry
Harrison's victory and Cook's voyages
Standardizing Greenwich as Prime Meridian
Time zones and modern navigation
Conclusion: The legacy of precise timekeeping
Outro and sponsors: Short History of Ned Kelly
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