8o THE POPULAR SCIENCE MONTHLY. 



this case it will be observed that the original sound and the 

 jangle both came from the same place, so that it was not so diffi- 

 cult to locate. 



There was no mistake about it, as the old lady sang through 

 each verse, and at every verse the jangle appeared. She, however, 

 seemed totally unconscious of any discordant effect in her vocal 

 effort, and I have no doubt did not notice it at all. 



The difficulty of locating sounds correctly may be illustrated 

 in one way by the advantage the ventriloquist takes of this 

 peculiarity, for in the exercise of his art he can speak in such 

 manner that his voice appears to come from an image beside him, 

 or from some distant place. Analogous to optical delusion, the 

 ventriloquist might be well termed an exponent of sound delu- 

 sion ; and, again, the attempt to deceive an audience as to the 

 source of sound by a supposed performer on the stage going 

 through the motions of playing upon a cornet or other musical 

 instrument while the real performer is behind the scenes is often 

 successfully practiced. I was once present at a practical test 

 made before an audience which will further illustrate how diffi- 

 cult it is to determine whence a sound comes. A gentleman 

 took his seat in a chair upon the platform and was blindfolded. 

 Another party held a snapper sounder in one hand and would 

 produce the snap now directly over his head, now to one side, be- 

 hind his back, etc. At each sound of the snapper the blindfolded 

 party was requested to point in the direction from which he 

 thought the sound proceeded. In almost every attempt he 

 pointed in the wrong direction. 



As a result of observations which I have made among animals, 

 there is a wide difference between them as to the ability of dis- 

 tinguishing and correctly locating sound ; for instance, men and 

 women have not such an acute sense of quickly locating a sound 

 as some of the four-footed animals, such as the rabbit, mule, the 

 cat, and some species of dogs. It is quite probable that the 

 ability these animals have to move their ears about, and long ears 

 at that, accounts for the quickness they have for determining the 

 direction of a sound. I have often tried the experiment of test- 

 ing this sense of correctly locating sound with a cat by imitating 

 the squeak of a mouse by whistling through the teeth. The first 

 squeak or two would result in the cat springing up and, with ears 

 erect and moving about, listen for the next sound ; at the second 

 attempt the cat would as a rule look directly into my face, as 

 much as to say, " You can't fool me that way," would settle down 

 again to its nap, and no further imitation squeaks would start it 

 up again. 



The not infrequent result of any unusual sound behind a mule 

 illustrates how well his sense of hearing serves him in this re- 



