SCIENCE OF COMMON THINGS. 121 



Scale of music. Sounds of Instruments. How birds sing. 



called a musical concord ; when the effect is disagree- 

 able, it is called a discord. 



7* GO What is the gamut or diatonic scale of music ? 



It consists of seven notes, which are distinguished by 

 the seven first letters of the alphabet, or by the seven 

 syllables, do, re, mi, fa, sol, la, si. 



7*61 Why do flutes, etc., produce musical sounds 1 



Because the breath of the performer causes the air 

 in the flute to vibrate / and this vibration sets in mo- 

 tion the sound-waves of the air. 



7*03 Why does a, fiddle-string give a musical sound f 



Because the bow drawn across the string causes it to 

 vibrate ; and this vibration of the string sets in motion 

 the sound-waves of the air, and produces musical notes. 



7*63 Why does a drum sound t 



Because the parchment head of the drum vibrates 

 from the blow of the drum-stick, and sets in motion the 

 sound-waves of the air. 



7*64 Why do pianofortes produce musical sounds ? 



Because each key of the piano (being struck with the 

 finger) lifts up a little hammer which knocks against a 

 string / and the vibration thus produced sets in motion 

 the sound-waves of the air. 



7*35 Why is an instrument flat when the strings are unstrung? 



Because the vibrations are too slow / in consequence 

 of which the sounds produced are not shrill or sharp 

 enough. 



7*S Why do birds alone, of animals, produce musical notes f 



Because they alone are gifted with a vocal organiza- 

 tion, which enables them to produce musical notes. In 

 other animals, the larynx is placed wholly at the 

 upper end of the windpipe ; but in birds it is sepa- 

 rated, as it were, into two parts, one placed at each 

 extremity. 



7*67* Why cannot birds be so correctly said to sing as to whistle f 



Because natural singing is an exclusive privilege of 

 man. 



