330 HISTORY OF ACOUSTICS. 



force of the striking body, the physical constitution of 

 the body struck, and other causes,) he comes to the 

 conclusion, that "the things which produce acute- 

 ness in sounds, are a greater density and a smaller 

 size ; the things which produce graveness, are a 

 greater rarity and a bulkier form." He afterwards 

 explains this so as to include a considerable portion 

 of truth. Thus he says, " That in strings, and in 

 pipes, other things remaining the same, those which 

 are stopped at the smaller distance from the bridge 

 give the most acute note ; and in pipes, those notes 

 which come through holes nearest to the mouth- 

 hole are most acute." He even attempts a further 

 generalization, and says that the greater acuteness 

 arises, in fact, from the body being more tense ; and 

 that thus "hardness may counteract the eifect of 

 greater density, as we see that brass produces a 

 more acute sound than lead." But this author's 

 notions of tension, since they were applied so gene- 

 rally as to include both the tension of a string, and 

 the tension of a piece of solid brass, must neces- 

 sarily have been very vague. And he seems to have 

 been destitute of any knowledge of the precise 

 nature of the motion or impulse by which sound is 

 produced ; and, of course, still more ignorant of the 

 mechanical principles by which these motions are 

 explained. The notion of vibrations of the parts of 

 sounding bodies, does not appear to have been 

 dwelt upon as an essential circumstance ; though in 

 some cases, as in sounding strings, the fact is very 



