Why was Greenwich chosen as the prime meridian in 1884, according to Jonathan Betts?

Jonathan Betts said the International Meridian Conference in Washington in 1884 was mainly about cartography: the world's charts needed one shared meridian. By then 72% of the world's shipping already used charts with Greenwich as zero, so although the decision was political it was also common sense. The same meridian then became the reference for time and the global time-zone system. Betts noted France abstained and took about 30 years to accept it.

• Jim Bennett said longitude at sea could be found with a clock carrying the time of a home meridian.
• Bennett said Huygens built a sea clock for longitude in the hope of making money from it.

▸In their words

“The drive for accuracy isn't coming out of domestic timekeeping here.” Jim Bennett · at 38:31 — open in the transcript →

Source: our own transcription of the episode. The full conversation is on In Our Time (2026-10-12). Read the whole episode summary →

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