Note 27 — Chapter II · THE DAVENPORT BROTHERS
Reading edition
As to the delusion of sound. Sound waves are deflected just as light waves are reflected by the intervention of a proper medium and under certain conditions it is a difficult thing to locate their source. Stuart Cumberland told me an interesting test to prove the inability of a blindfolded person to trace sound to its source. It is exceedingly simple; merely clicking two coins over the head of the blindfolded person.