II. TO HIGHGATE. 31 



the vibrations and tremors of the air pro- 

 duce different sounds? These are mysteries 

 which the most intelligent naturalists have 



O 



not yet sufficiently explained. 



All that we know on this subject, is, that 

 the quick percussion of bodies is sufficient 

 to produce sound; and that, in order 'to 

 its production, it is necessary that the air 

 should be thrown into tremors and undu- 

 ]ations. 



With respect to sonorous bodies, there 

 are some endued with a greater, arid others 

 with a less, degree of elasticity; to which 

 principle must be referred the mechanism 

 of sounds. 



But how wondeful the phenomena thus 

 presented to our view ! It is well known 

 that a sonorous body always experiences 



vibrations when struck or thrown into ac- 



_ 



tion ; and in proportion as these vibrations 

 ure more or less quick, sounds are produ- 

 ced more or less shrill, and more or less 

 deep. 



The 



