the weather in a bell

There are lots of little facts wandering around in the world. Sometimes they come packaged neatly and in ways that make you go huh. 

During World War Two, BBC News was broadcast to Nazi-occupied Europe. Each news programme opened with a live broadcast of Big Ben tolling the hour — the magical sound of freedom. Ingenious German physicists found a way to determine the weather conditions in London based on tiny differences in the tone of the broadcast ding-dongs. This information offered invaluable help to the Luftwaffe. When the British Secret Service discovered this, they replaced the live broadcast with a set recording of the famous clock.

The clock struck one and down he run.

source:

Sapiens: a brief history of humankind

by Yuval Noah Harari

2015. HarperCollins, New York