234 LETTERS ON NATURAL MAGIC, 



gestures to the words spoken by the man. So powerful, 

 indeed, is the influence of this deception, that if a jack- 

 ass placed near the man were to open its mouth, and 

 shake its head responsive to the words uttered by his 

 neighbour, we would rather believe that the ass spoke 

 than that the sounds proceeded from -a person whose 

 mouth was shut, and the muscles of whose face were in 

 perfect repose. If our imagination were even directed 

 to a marble statue or a lump of inanimate matter, as the 

 source from which we were to expect the sounds to issue, 

 we would still be deceived, and would refer the sounds 

 even to these lifeless objects. The illusion would be 

 greatly promoted if the voice were totally different in 

 its tone and character from that of the man from whom 

 it really comes ; and if he occasionally speak in his own 

 full and measured voice, the belief will be irresistible that 

 the assumed voice proceeds from the quadruped or from 

 the inanimate object. 



When the sounds which are required to proceed from 

 any given object are such as they are actually calculated 

 to yield, the process of deception is extremely easy, and 

 it may be successfully executed even if the angle between 

 the real and the supposed directions of the sound is much 

 greater than the angle of uncertainty. Mr. Dugald 

 Stewart has stated some cases in which deceptions of this 

 kind were very perfect. He mentions his having seen 

 a person who, by counterfeiting the gesticulations of a 

 performer on the violin, while he imitated the music by 

 his voice, riveted the eyes of his audience on the instru- 

 ment, though every sound they heard proceeded from his 

 own mouth. The late Savile Carey, who imitated the 

 whistling of the wind through a narrow chink, told Mr. 

 Stewart that he had frequently practised this deception 

 in the corner of a coffee-house, and that he seldom 

 failed to see some of the company rise to examine the 



