S8 The Sounds of the Consonants. 



the pitch and intensity of a note depend on the rapidity and 

 amplitude of its vibrations, its richness, and indeed all 

 that serves to give character to the note, depend on the num- 

 ber and kind of secondary vibrations with which the main 

 vibration is attended. Thus if the note is attended by its 

 octave, that is, if in addition to the vibrations which give 

 the note itself, there are present a secondary set of vibrations 

 of twice the rapidity, then we have a sound which the ear 

 recognises at once as musically the same note, and yet it 

 perceives a richness and fulness which was not present in 

 the simple tone. If to this double set of vibrations there 

 be added a third set, three times as rapid as the first, there 

 is again a change in the quality of the tone ; and while a 

 musician would say that the note was the same, the ear 

 would nevertheless declare that though the pitch and inten- 

 sity were the same, the character is notwithstanding quite 

 different. 



It was from the consideration of this last element, the 

 quality of the note, that Helmholtz was able to originate 

 the theory now generally accepted as to the nature of the 

 vowel sounds. Every set of vibrations given off either by 

 the human voice or by any musical instrument tends to 

 strengthen itself by the addition of a series of harmonics, 

 the first being twice as rapid as itself, the next three times, 

 the next four times, the next Rve times, and so on. Thus, 

 if the sound be C we may have this note strengthened by 

 the addition of the C above, by the G above that, by the 

 next C, the next E, the next G again, and so on. 



Now it is possible by means of resonators to strengthen 

 any one of these secondary vibrations, and so completely 

 alter the character of the note produced ; if a person were 

 to sing the same note through funnels of different shapes 

 the sounds would still be recognised by the ear as the same 

 note, but each would have its own distinctive character. 



This is all that takes place when a vowel is pronounced 

 by a human voice ; a certain note is emitted by the larynx, 

 the mouth is shaped into a resonator so as to strengthen 

 certain of the harmonics of that note. If the mouth is 

 partially opened, and the cavity made somewhat round by 

 the action of the under-jaw, we have the second partial tone 

 strengthened and made equal, or in some cases more intense 

 than the fundamental note ; the result is that the primary 

 vibration is followed by a second equal to it, and so the 

 phonogram gives for the long sound of 5 a series of dots 



