170 THE PHILOSOPHY 



accordingly, are extremely fond of noife. It roufes their attention, 

 and conveys to them the agreeable fenfation of found ; but feeble 

 founds are not perceived, which gives infants, like deaf perfons, the 

 appearance of inattention, or rather of ftupidlty. 



The force or intenfity of found is augmented by refledion from 

 furrounding bodies. It is from this caufe that the human voice, or 

 any other noife, is always weaker, and lefs diftin(a:ly heard, in the 

 open air than in a houfe. 



The modifications of found are not lefs various than thofe of 

 taftes or odours. The ear is capable of diftinguifhing fome hundred 

 tones in found, and probably as many degrees of ftrength in the 

 fame tones. By combining thefe, many thoufand fimple founds, 

 which differ either in tone or in ftrength, are perceived and diftln- 

 guifhed by the ear. A violin, a flute, a French -horn, may each of 

 them give the fame tone ; but the ear eafily makes the diftindion. 

 The Immenfe variety of fenfations, arifing from the organs of fmell- 

 Ing, of tafting, and of hearing, enables animals to judge concerning 

 the nature and fuuation of external objedts. By habit we learn to 

 kno^ the bodies from which particular fpecles of founds proceed. 

 Previous to all experience, we could not diftinguifh whether a found 

 came from the right or the left, from above or below, from a greater 

 or a fmaller diftance', or whether it was the found of a coach, of a 

 drum, of a bell, or of an animal. By catching cold, I once had a 

 temporary deafnefs in my left ear. I was furprifed to find that I 

 had loft the faculty of perceiving the fituation from which founds 

 proceeded. If a dog barked on the left, I thought the noife came 

 from the right. This circumftance excited my curiofity : But, up- 

 on recolledlion, I knew that my left ear was deaf; and that every 

 found I heard was perceived folely by the right ; and, confequently, 

 I difcovered the caufe of the deception. * 



Hearing 



