INAUDIBILITY OF CERTAIN SOUNDS. 233 



which renders an experiment on this subject with 

 a series of small pipes among several persons 

 rather amusing. It is curious to observe the 

 change of feeling manifested by various indi- 

 viduals of the party, in succession, as the sounds 

 approach and pass the limits of their hearing. 

 Those who enjoy a temporary triumph are often 

 compelled in their turn to acknowledge to how 

 short a distance their little superiority extends." 

 In concluding his interesting paper on this sub- 

 ject, Dr. Wollaston conjectures that animals, like 

 the grylli (whose powers of hearing appear to 

 commence nearly where ours terminate), may 

 have the power of hearing still sharper sounds 

 which at present we do not know to exist, and 

 that there may be other insects having nothing 

 in common with us, but who are endowed with a 

 power of exciting, and a sense of perceiving, 

 vibrations which make no impression upon our 

 organs, while their organs are equally insensible 

 to the slower vibrations to which we are accus- 

 tomed. 



With the view of studying the class of sounds 

 inaudible to certain ears, we would recommend it 

 to the young naturalist to examine the sounds 

 emitted by the insect tribe, both in relation to 

 their effect upon the human ear, and to the 

 mechanism by which they are produced. The 

 Cicadse or locusts in North America appear, from 

 the observations of Dr. Hildreth,* to be furnished 

 with a bagpipe on which they play a variety of 

 notes. "When any one passes," says he, " they 

 make a great noise and screaming with their air- 



* Edinburgh Journal of Science, No. xvii., p. 158. 



