71. [70.] What a choir is, and the observation that by choirs spirits are introduced into a state of unanimity (as is the case when many speak and act together at the same time in unison), and that there is a harmony of sounds in their speech, may be found in Arcana Coelestia (The Secrets of Heaven), nos. 1648, 1649, 2595, 2596, 3350, 5182, 8115.