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
Minstrel in the Gallery "Cold Wind to Valhalla," and "Requiem" is the loveliest acoustic number in Tull's repertory, featuring nothing but Anderson's singing and acoustic guitar, Hammond-Hammond's bass, and a small string orchestra backing them". "Minstrel in the Gallery" received Gold Certification in both the United States and the UK and is the ninth best selling Jethro Tull album. The album peaked at No. 7 on the Billboard album chart, and at No. 20 in the UK Albums Chart – "Songs from the Wood" would sell better two years later in the UK. It also charted in Norway, reaching No. 13, and Austria, where