The Whispering Gallery of St Paul's
Whisper against the wall of St Paul's dome, and someone on the far side, more than 30 metres away, can hear you.
What was reported
Around the base of the dome of St Paul's Cathedral, more than 250 steps up, runs the Whispering Gallery. A whisper spoken close to the wall on one side can be heard clearly on the other, more than 30 metres away, while someone standing nearby may hear nothing.
The effect was a puzzle, and a favourite of visitors, long before anyone could explain it.
Explanations offered
In 1878 Lord Rayleigh showed that sound waves cling to the curved wall, reflecting along it in a series of short hops so they don't spread out and fade. Such 'whispering-gallery waves' are now used in physics, including in tiny devices that trap light in the same way.
- When
- Completed in the early 1700s
- Where
- St Paul's Cathedral, London, England
- Witnesses
- Visitors for three centuries
- Status
- Explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.