Whispering-gallery wave Whispering-gallery wave Whispering-gallery waves, or whispering-gallery modes, are a type of wave that can travel around a concave surface. Originally discovered for sound waves in the whispering gallery of St Paul’s Cathedral, they can exist for light and for other waves, with important applications in nondestructive testing, lasing, cooling and sensing, as well as in astronomy. Whispering-gallery waves were first explained for the case of St Paul's Cathedral circa 1878 by Lord Rayleigh, who revised a previous misconception that whispers could be heard across the dome but not at any intermediate position. He explained the phenomenon of travelling whispers with
Scottish National Portrait Gallery but the government in London refused to fund the venture. Eventually John Ritchie Findlay stepped in and paid for the entire building, costing £50,000. The museum was established in 1882, before its new building was completed. The London National Portrait Gallery was the first such separate museum in the world, however it did not move into its current purpose-built building until 1896, making the Edinburgh gallery the first in the world to be specially built as a portrait gallery. Special national portrait galleries remain a distinct Anglophone speciality, with the other more recent examples in Washington DC (1968), Canberra, Australia