234 Mr. Willis on the Vowel Sounds, 



destined for the performance of their other functions, from those 

 which are immediately peculiar to speech (if such exist.) 



In repeating experiments of this kind, it must always be 

 kept in mind, that the difterence between the vowels, depends 

 entirely upon contrast*, and that they are therefore best dis- 

 tinguished by quick transitions from one to the other, and by 

 not dwelling for any length of time upon any one of them. 

 A simple trial will convince any person, that even in the human 

 voice, if any given vowel be prolonged by singing, it soon 

 becomes impossible to distinguish what vowel it is. 



Vowels are quite a different affection of sound from both 

 pitch and quality, and must be carefully distinguished from 

 them. By quality, I mean that property of sound, by which 

 we know the tone of a violin from that of a flute or of a 

 trumijet. Thus we say, a man has a clear voice, a nasal voice, 

 a thick voice, and yet his vowels are quite distinct from each 

 other. Even a parrot, or Mr. Punch, in speaking, will pro- 

 duce A's, and O's, and E's, which are quite different in their 

 qualiti/ from human vowels, but which are nevertheless distinctly 

 A's, and O's, and E's. Again, as to pitch, all the vowels may be 

 sung upon many notes of the scale, but of this more here- 

 after. 



Eulerf has discriminated these affections of sound, and dis- 



* Kenipeleii has remarked this with bis usual acuteness. Describing one of his early 

 experiments, with a machine something like fig. 5, from which he obtained some of the vowels 

 by covering its mouth with his left hand, he says, " J'oblins d'abord diverses voyclles, suivant 

 " i)ue j'ouvrois plus ou nioius la main gauche. Mais cela n'arrivoit que lorsque je faisois 

 " rapidement de suite divers mouvemens avec la main et les doigts. Lorsqu'au contraire 

 " je conservois pendant quelque terns la m^me position quelconiiue de la main, il me paroissoit 

 " que je n'entendois qu'un A. Je tirai bient6t de ceci la consequence, que les sons de la 

 " parole ne deviennent bien distincts que par la proportion qui existe entr'eux et qu'ils n'ob- 

 " tiennent leur parfaite clarte que dans la liaison des mots entiers et des phrases." p. 400. 



t De motu aeris in tubis. Schol. ll. and ill. Prop. 73. A'oii. Comm. Petrop. xvi. and 

 Mem. Acad. Berlin 1767, p. 354. See also Bacon Hist. Nat. §. 290. 



