LESSON XVIII. 



ON SOUNDS AND ECHOES. 



- Sweet music breathe, 

 Above, about, or underneath, 

 Sent by some spirit to mortals good. MILTON. 



ANOTHER peculiar motion of the air remains 

 yet to be considered, which is, that by means of 

 which sounds are rendered audible or sensible to 

 us, under all their different affections and circum- 

 stances. Of the philosophy of sounds, Music is un- 

 doubtedly the essential and most refined part ; and 

 we find that persons in general are exceedingly fond 

 of musical sounds, being thereby affected with the 

 most agreeable and ravishing sensations. It is my 

 province in this place to give no more of the science 

 of Music than what relates to the production of 

 musical sounds, and indeed of sounds in general, 

 to which I shall now proceed*. 



Experiments 



* Though it be somewhat foreign to the subject immedi- 

 ately under discussion, yet I cannot pass by an opportunity 

 of suggesting an obvious improvement in the practice of Mu- 

 sic ; the use of which has been frequently urged, though it be 

 not yet generally acceded to. This improvement is no other 

 than the substitution of proper characters to denote the dif- 

 ferent kinds and velocities of musical time, instead of those 



vague, 



