412 MUSICAL SOUNDS. 



soon as they are struck, and set in motion 

 the sound-waves of the air. 



Q. Why do FLUTES, $c. produce musical 

 sounds ? 



A. The breath of the performer 

 causes the air in the flute to vibrate, and 

 sets in motion the sound-waves of the air. 



Q. Why do PIANO-FOETES produce musical 

 sounds ? 



A. The keys of the piano (being 

 struck with the finger) lift up a little 

 hammer which knocks against a string ; 

 and the vibration thus produced, sets in 

 motion the sound-waves of the air. 



Q. Why are SOME notes BASS and some 



TREBLE ? 



A. Slow vibrations produce bass or 

 deep sounds; whereas, quick vibrations 

 produce shrill or treble sounds. 



Q. Why is an instrument FLAT when the 

 STRINGS are UNSTRUNG ? 



A. Because the vibrations are too 

 slow; in consequence of which, the 

 sounds produced are not shrill or sharp 

 enough. 



Q. Why can persons living a mile or two from 



