1865.] Squire on the Quality of Musical Sounds. 603 



not the fundamental of the reed, but one of its upper tones. Under 

 these circumstances this particular upper tone will be prominently 

 strengthened, and the sound will acquire a peculiar character re- 

 sembling more or less the vowels of the human voice. In fact, the 

 vowels are sounds produced by membranous reeds — the vocal chords, 

 the resonance tube of which — the cavity of the mouth, can be so 

 modified in width, length, and form as to fortify sometimes this, some- 

 times that, upper tone of the sound. The easiest and surest way of 

 determining the proper tone which corresponds to the position of the 

 mouth for each vowel is to gently whisper any vowel, retain the 

 mouth fixed in that position, and test it by holding before it tuning- 

 forks of various pitch until one is found, the sound of which is 

 intensified by the resonance of the mouth. By passing in this way 

 from one vowel to another, the tones peculiar to each position of the 

 mouth may be ascertained. The determinations given below are 

 those of Helmholtz, and apply to the vowels pronounced in the 

 German way. Both for and for U the opening of the mouth is 

 narrowed by the lips, while the greatest possible space is given in the 

 middle by drawing down the tongue, so that the mouth approximates 

 to the form of a bottle with no neck. In such bottles the smaller the 

 opening the lower the tone. This is borne out by these vowels. For 

 U, in which the opening is the smallest and the space the largest, the 

 proper tone is found to be f, and when the U is gradually converted 

 into by opening the mouth the resonance rises also, until for a pure 

 O the proper tone of the mouth becomes b' flat. The position of the 

 mouth for is particularly favourable for resonance, the opening 

 being neither too large nor too small, and the hollows sufficiently 

 large. If a fork which is tuned to b' flat is struck and placed before 

 the mouth while the vowel O is gently whispered, the sound of the 

 fork becomes so full and loud that it can be heard by a large audience, 

 but if the position of the mouth is now changed through CE and ^E 

 to A (as in father) the resonance rises a whole octave to b"-flat. The 

 sharper English and Italian A rises to d", that is, a third higher. For 

 these vowels there appears to be only one peculiar tone, and the 

 theory of sounds produced in spaces of this shape would not lead us 

 to expect otherwise. Starting once more from A through the series 

 A, M, E, I, we find that the lips are so far drawn back as not them- 

 selves to produce a narrowing, but that a narrowing of a different 

 kind is effected by the front part of the tongue and the hard gums, 

 while the space over the larynx is widened by drawing in the root of 

 the tongue. The form of the mouth is now that of a bottle with a 

 narrow neck produced by the upper surface of the tongue and the 

 gum. For * I the hollow of the bottle is the largest, and the neck the 

 smallest. For M the whole channel is rather wide. When these 

 positions are tested two tones may be distinctly detected, the one 

 corresponding to the large space, the other to the narrow tube-like 

 passage between the gum and the tongue, so that the whole arrange- 

 ment resembles in principle the organ pipes already described, in 



* I pronounced rather like the English E, and the E like a flat A. 

 VOL. II. 2 T 



