336 SPEECH. [BOOK in. 



proportion to the other tones ; in the case of some vowels two tones 

 are so reinforced. The tone thus reinforced is generally a partial 

 tone, but may be the fundamental tone. When the vowel is sung 

 or spoken in notes of different pitch the particular partial tone 

 which is reinforced will occupy different positions in the series of 

 partial tones ; it may be the first, second, third or other partial 

 tone according to the pitch of the fundamental tone. 



That the vowel chamber does act in this way as a resonator 

 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 particular 

 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 reinforce- 

 ment 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 

 particular 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 de- 

 scribed. Again, as we said in dealing with hearing ( 850), 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 

 contrast 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 consonants. The noise of 

 the whisper, though weak, contains multifarious vibrations, contains 



