426 GENERAL SCIENCE 



brations which are exact multiples of the fundamental, they are 

 called harmonics. 



International Standard Pitch. All musicians have agreed that 

 middle A of the violin shall be produced by 435 vibrations per 

 second. Instruments tuned to this A, with other tones having the 

 proper ratio, are said to be tuned to International Standard Pitch. 



Tones from String Instruments. All string instruments depend 

 for their tones upon the size of their strings, the length, and the 



FIG. 317. This instrument has been a favorite in all generations because of 

 the wide range of expression which may be produced. What would be 

 the difference in the tone if the strings of the harp were plucked in the 

 center? 



tension of the strings. For example, the strings which produce 

 the bass notes of a piano are large and long, while those which pro- 

 duce high tones of a piano are short and of smaller diameter. The 

 tone is maintained by causing a certain tension of the string. If the 

 tension is reduced, it is necessary to tighten the string. 



Experiment. Notice the effect of tightening the string on a sonometer, also 

 the effect of shortening the string, and, if possible, the effect upon two strings 



