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
National Portrait Gallery, London National Portrait Gallery, London The National Portrait Gallery (NPG) is an art gallery in London housing a collection of portraits of historically important and famous British people. It was the first portrait gallery in the world when it opened in 1856. The gallery moved in 1896 to its current site at St Martin's Place, off Trafalgar Square, and adjoining the National Gallery. It has been expanded twice since then. The National Portrait Gallery also has regional outposts at Beningbrough Hall in Yorkshire and Montacute House in Somerset. It is unconnected to the Scottish National Portrait Gallery in Edinburgh, with which