CHAP, vii.] SOME SPECIAL MECHANISMS. 1095 



for a particular tone is shewn by moulding the cavity into the 

 proper form for uttering a particular vowel, and bringing before 

 the mouth a series of sounding tuning-forks of different pitch ; 

 it will be found that it is the sound of one tuning-fork and one 

 in particular which is reinforced and made louder, namely, the 

 one whose pitch corresponds to the fundamental tone of the par- 

 ticular vowel cavity ; in the case of the vowel U for instance it 

 will be the tuning-fork having the pitch b. On the other hand 

 that what we recognize as vowel sounds do result from the rein- 

 forcement in a musical sound of a particular tone or of particular 

 tones may be shewn by setting into vibration a series of tuning- 

 forks of different pitch, in imitation of a musical sound with its 

 constituent tones, and then in turn reinforcing the sound of par- 

 ticular tuning-forks by the help of artificial resonators. When 

 this is done the reinforcement of the appropriate tone gives rise 

 to a vowel sound, the reinforcement of b giving rise to U and so 

 on. The curves moreover described by the vowel sounds in the 

 phonograph, in which the vibrations of the air transmitted to a 

 thin plate or membrane are made to write on a recording surface, 

 are in form such as would be described by sounds in which 

 particular constituent tones were reinforced in the manner 

 described. Again, as we said in dealing with hearing ( 629), 

 when a note is sung into the open piano, the particular strings 

 of the piano corresponding to the constituent tones of the note 

 sung are thrown into sympathetic vibration ; in the sound thus 

 returned by the piano the nature of the vowel on which the note 

 was sung may be recognized ; the string corresponding to the 

 characteristic tone of the vowel is thrown into appropriately 

 strong vibrations. 



The nature of the vowel sounds is especially well illustrated 

 by the kind of speech which we call whispering. In this, in con- 

 trast to audible speech, no musical sounds are generated by the 

 vocal cords. A laryngeal sound is generated but it is a noise, not 

 a musical sound, and is caused by the friction of the air as it 

 passes through the glottis, which assumes a peculiar form, the 

 processus vocales projecting inwards towards each other, leaving 

 the cartilaginous glottis as well as the greater part of the mem- 

 branous glottis more or less open. This noise, like the musical 

 sound of audible speech, is modified by the parts of the mouth 

 and pharynx, and in it we may recognize vowels and conso- 

 nants. The noise of the whisper, though weak, contains multi- 

 farious vibrations, contains among other and irregular vibrations, 

 the regular vibrations corresponding to the several vowels. 

 When we whisper a vowel, we ' set ' the vowel chamber so that 

 it may reinforce the set of vibrations of the particular pitch 

 characteristic of the vowel; and a well-trained ear may recog- 

 nize in the whispered vowel the dominant tone. 



A vowel then is essentially a musical sound of a special 



