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"It is apparent that the auditor, in this case, must be placed in the centre from which the sound proceeds, to receive the greatest effect. But if the shape of the room be elliptical, the sound may be made in one part, and the echo will be heard in another part, because the ellipse has two points, called foci, at one of which, the sound being produced, it will be concentrated at the other." -Comstock 1850

Whispering Gallery

"It is apparent that the auditor, in this case, must be placed in the centre from which the sound proceeds,…