298 



MUSICAL INSTRUMENTS 



within. Varying pitches are obtained largely by the vary- 

 ing wind pressure of the musician ; if he breathes fast, the 



I 2 L3 3 



FIG. 191. i, kettledrum ; 2, bass drum ; 3, cymbals. 



pitch rises ; if he breathes slowly, the pitch falls. All of these 

 instruments, however, except the trombone possess a few valves 



FIG. 192. The seating arrangement of the Philadelphia orchestra. 



