SOUND AND MUSIC 81 



song-birds, and the earth is girdled with music, and 

 the perfection of the work of the air medium is re- 

 vealed. 



What shall we say also of the waters of the sea, occu- 

 pied for miles with the motions of a bell, with those of 

 the articulate sounds of a speaking-trumpet. 



The trampling of men and horses, as we have seen, 

 create near and far waves, which reach the ear, and pro- 

 duce in it the sensation of sound. The particles along 

 the ground receive the motions with a sensibility that 

 never fails, and send them forward with a faithfulness 

 that knows not how to come short. The very character- 

 istics of the sounding body they transmit. The peculiar 

 features distinguishing it, and revealing its nature, they 

 accurately convey. The motions are invisible. The eye 

 cannot detect them. They send no messengers to it. To 

 it the ground is at rest and is still. To the feet and the 

 hands, or any part of the sense of touch, they exist not. 

 But to the ear they are abundantly evident. It has 

 power to take them in. It has the sensibility which 

 enables it to receive and convey them to the brain, from 

 which they pass to the perceiving nature, and to it they 

 are transformed into sounds. The particles of the ground 

 are so constituted, and possess a freedom of action among 

 themselves, which enable them to respond to the tramp 

 of men and horses, and not to them only but to the 

 music of the drum, the pipe, the many instruments of 

 the band, and to execute, over a wide extent, harmonic 

 motions thrilling to consider. The whole ground is by 

 such means thrown in its every particle into activity, in 

 which condensations and rarefactions are being executed 

 with a regularity which defies description. 



What to appearance is more difficult to move than the 

 particles which make up bricks and stones. They seem 

 6 



