624 



PHYSIOLOGY 



(1) By recording the vibrations emitted by the voice by means of the 

 manometric flame. 



(2) By recording the vibrations by means of a gramophone. 



(3) By measuring the intensity of vibration of series of resonators. All 

 the above methods show that there must be some change, even if it is slight. 



(4) By running a gramophone record of a bass voice at an increased speed 

 so that the notes were those of a treble. If now the pitches of note and 

 vowels were in constant ratio the quality of the vowels should not change 

 when the speed is thus increased. Experiment shows that the words are 

 greatly altered, losing their O's and A's and taking E and I instead. 

 This shows clearly that change in pitch of the vowels is not nearly 

 as great as that of the note sung with them. We must conclude therefore 

 that neither those who say there is no change, nor those who say there is con- 

 stant ratio, are right, but that the truth lies between the two extremes. The 

 pronunciation even of the simplest vowel sound differs in different individuals. 

 For instance, those pronounced by a Londoner differ from those pronounced 

 by a man from Manchester or from Yorkshire, and the French vowels differ 

 somewhat in pitch from those employed by the German, and these again from 

 those employed by the average Englishman. 



The characteristic notes were given by Helmholtz as follows : 





jiv r/ ' T f T ^ 



?^ ~ 



U A El 



If the five vowels are whispered loudly, the gradual rise in pitch of the 

 tone is easily perceptible. We do not in this way however note the lower 

 component of the sound in the E and I ; this can be brought out by a 

 simple device (Fig. 313). If we place the mouth in the position necessary 

 to produce these different vowels, and then percuss over the cheek, we 

 obtain the typical note for each vowel, the air in the mouth cavity being 

 set into vibration by the percussion. Now shift the ringer, which is to be 



A (ar) U (oo) I (ee) 



Shape of the oral cavity in the production of the vowel sounds, A,U,I. 



(GRUTZNER.) 



