Whispering gallery to the walls, an effect that was discovered in the whispering gallery of St Paul's Cathedral in London. The extent to which the sound travels at St Paul's can also be judged by clapping in the gallery, which produces four echoes. Other historical examples are the Gol Gumbaz mausoleum in Bijapur and the Echo Wall of the Temple of Heaven in Beijing. A hemispherical enclosure will also guide whispering gallery waves. The waves carry the words so that others will be able to hear them from the opposite side of the gallery. The gallery may also be in the form
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