64 UNCERTAINTY OF SOUNDS. 



may appear to be sometimes on one side of us, 

 and sometimes on another. The swelling and 

 sinking of the sound are the only means that we 

 have of ascertaining whether it is coming nearer 

 to us, or going farther away ; and there are many 

 circumstances by which we may be deceived even 

 then. A clump of trees, or any other object that 

 can deaden the sound, will make us think that 

 which is actually approaching us is retiring ; and 

 the clearing of such an obstacle will make that 

 which, in reality, is approaching, be heard as if it 

 were going away. Thus the ear has, in itself, no 

 more power of enabling us to discover that the 

 voice which we hear in nature is the true voice, 

 than it has of letting us know that what our fellow 

 men tell us is the truth. 



It is principally on account of this want of con- 

 nection between the hearing of sounds, and know- 

 ledge of the nature, or even the existence of the 

 sounding body, that we are more startled by sud- 

 den, loud, and unusual sounds, than by any other 

 sudden and strong affection of the senses. In the 

 discharging of fire-arms, it is the report which 

 frightens both men and animals, and not the bullet, 

 though the report is perfectly innocent, and the 

 bullet carries wounds and death on its wings. 

 Lightning, too, is not only much more sublime 

 than thunder, but its power is, in some instances, 

 tremendous ; so that we cannot set bounds to its 

 effects ; and yet it is the harmless din of the thun- 

 der which terrifies. The motion of the air, which 

 produces sound, seems to be quite different in kind 

 from that which overcomes resistance, and affects 

 the skin and the muscles. The ear will catch the 

 tones of a bell at the distance of eight or ten miles 



