32 The jEoUan Harp. [Jan., 



The sounds are produced by the vibrations of the string ; the varia- 

 tions of tone are caused by changes in the frequency of these vibrations, 

 together with changes in the length of the vibrations, or leaves. Fix 

 your eye upon a chord which is sounding its lowest or key-note, and 

 you will perceive that its entire length is in motion — i. e., its wave 

 length is equal to the string's length. The note thus produced, we 

 may call C. This note, however, is very seldom produced by the 

 wind, but the lowest note sounded is an octave above this, viz : C^ 

 and is produced by the vibration of the chord in two equal portions, 

 while the central point of it remains quiet, i. e., becomes a jwde. If 

 now the breeze freshens, somewhat, a higher note is heard — ^ fifth 

 above, which is Gr. In this case the chord vibrates in three equal 

 portions, with tiro nodes. A stronger breeze gives us the third C, 

 di fourth above, which is caused by three nodes, dividing the string into 

 four equal waves. A still stronger breeze, a wind arises, and the 

 new note evoked from the trembling string is E, a major third aho\e, 

 caused hj four nodes dividing the string into five equal waves. A 

 swifter wind — a gale — lifts the tone Siminor third, to G, by means of 

 five nodes with six waves. A stronger gale breaks the wave into 

 seven equal parts with six nodes, giving us another minor third, viz., 

 Aij:. (sharp.) The next note which is never heard except the strings 

 be swept by a tempest, is the fourth octave C, produced by seven 

 nodes with eight equal waves. 



Thus each string is capable of yielding seven or eight notes, de- 

 pending upon the force of the wind. Another note still higher is 

 possible in a wind of extreme violence, which note would be a single 

 tone above, viz., D, with eight notes and nine waves. The entire 

 scale of the ^olian harp is therefore as follows : 



c c G, C, E, G, A#, C, D. 



The number of nodes for each of these notes is : 



0, 1, 2, 3, 4, 5, 6, 7, 8. 

 The number of wave-lengths for each is: 



1, 2, 3, 4, 5, 6, 7, 8, 9. 

 The lengths of the waves compared with the whole string are ; 



') 2) 3) 4' SI C' T S' 9 > 



and since the number of vibrations per second is inversely as the 

 length of the wave, this will be proportionately as 



1, 2, 3, 4, 5, 6, 7, 8, 9; 

 that is, if our string be tuned to C, there will be vibrations per sec- 

 ond for each note, 



