STRINGS AND THEIR TONES 



287 



FlG. 181. The length of a string influences 

 the pitch. 



string into two equal parts by inserting the bridge midway 

 between the two ends ; and pluck either half as before. The 

 note given forth is of a de- 

 cidedly higher pitch/ and if 

 by means of the siren we 

 compare the pitches in the 

 two cases, we find that the 

 note sounded by the half wire 

 is the octave of the note 

 sounded by the entire wire ; 

 the frequency has been doubled by halving the length. If 

 now the bridge is placed so that the string is divided into 

 two unequal portions such as I : 3 and 2 : 3, and the shorter 

 portion is plucked, the pitch will be still higher ; the shorter 

 the length plucked, the higher the pitch produced. This mov- 

 able bridge corresponds to the finger of the violinist; the finger 

 slides back and forth along the string, thus changing the 

 length of the bowed portion and producing variations in pitch. 

 If there were but one string, only one pitch could be 



FIG. 182. Only one half of the string is bowed, but both halves vibrate. 



sounded at any one time ; the additional strings of the violin 

 allow of the simultaneous production of several tones. 



