PRELUDE TO THE SOLUTION OF PROBLEMS. 331 



obvious. And the notion of vibrations of the air 

 does not at all appear in ancient writers, except so 

 far as it may be conceived to be implied in the 

 comparison of aerial and watery waves, which we 

 have quoted from Vitruvius. It is, however, very 

 unlikely that, even in the case of water, the motions 

 of the particles were distinctly conceived, for such 

 conception is far from obvious. 



The attempts to apprehend distinctly, and to 

 explain mechanically, the phenomena of sound, gave 

 rise to a series of Problems, of which we must now 

 give a brief history. The questions which more 

 peculiarly constitute the science of acoustics, are 

 those concerning, those affections of the air by 

 which it is the medium of hearing. But the mo- 

 tions of sounding bodies have both so much con- 

 nexion with those of the medium, and so much 

 resemblance to them, that we shall include in our 

 survey researches on that subject also. 



