ANIMALS 221 



CHAPTER VIIT 



ON HEARING.* 



As the sense of hearing, as well as of sight, gives us notice cf re 

 mote objects, so, like that, it is subject to similar errors, being capa 

 ble of imposing on us upon all occasions, where we cannot rectify it 

 by the sense of feeling. We can have from it no distinct intelligence 

 of the distance from whence a sounding body is heard ; a great noise 

 far off, and a small one very near, produce the same sensation ; and ; 

 unless we receive information from some other sense, we can never 

 distinctly tell whether the sound be a great or a small one. It is not 

 till we have learned, by experience, that the particular sound which 

 is heard, is of a peculiar kind ; then we can judge of the distance 

 from whence we hear it. When we know the tone of the bell, we 

 can then judge how far it is from us. 



Every body that strikes against another produces a sound, which is 

 simple, and but one in bodies which are not elastic, but which is often 

 repeated in such as are. If we strike a bell, or a stretched string, for 

 instance, which are both elastic, a single blow produces a sound, which 

 is repeated by the undulations of the sonorous body, and which is mul- 

 tiplied as often as it happens to undulate or vibrate. These undula, 

 tions each strike their own peculiar blow; but they succeed so fast t 

 one behind the other, that the ear supposes them one continued 

 sound : whereas, in reality, they make many. A person who should, 

 for the first time, hear the toll of the bell, would, very probably, be 

 able to distinguish these breaks of sound ; and, in fact, we can readily 

 ourselves perceive an intension and remission in the sound. 



In this manner, sounding bodies are of two kinds; those unelastic 

 ones, which being struck, return but a single sound; and those more 

 elastic, returning a succession of sound ; which uniting together form 

 a tone. This tone may be considered as a great number of sounds, 

 all produced one after the other, by the same body, as we find in a 

 bell, or the string of a harpsichord, which continues to sound for some 

 time after it is struck. A continuing tone may be also produced from 

 a non-elastic body, by repeating the blow quick and often, as when 

 we beat a drum, or when we draw a bow along the string of a fiddle. 



Considering the subject in this light, if we should multiply the num- 

 ber of blows, or repeat them at quicker intervals upon the sounding 

 body, as upon the drum, for instance, it is evident that this will have 

 no effect in altering the tone; it will only make it either more even, 

 or more distinct. But it is otherwise, if we increase the force of the 

 blow: if we strike the body with double weight, this will produce a 

 tone twice as loud as the former. If, for instance, I strike a table, 

 with a switch, this will be very different from the sound produced by 

 striking 't with a cudgel. Hence, therefore, we may infer, that all 

 bodies give a louder and graver tone, not in proportion to the number 

 of times they are struck, but in proportion to the force that strike* 



* This chapter is taken from Mr. Buffon. except where marked by inverted comtrut* 



