EXPERIMENTAL PHONETICS. 



253 



~VCi» "J\A — 



\J\r—AlV — VV — AA' — Af^^—AN- — ^ 



is it tliat gives tlio peculiar <iuality to tlie sound of a xowel^ How is 

 it that we can, l)y the ear, identity the sound of any vowel, whether it 

 be spoken or sung'^ How is it that if we sing a vowel on the notes of 

 a scale we can still identif}' the vowel whatever may ])e the pitch of the 

 note on which it is sung? The scientitic 

 imestigation of the nature of vowels l)e- 

 gins with "\\'illis," who, in lS2i), imitated 

 the larynx l)y means of a reed, above 

 which he placed a resonator, tuned to one 

 of the harmonics of the reed. He also 

 imitated vowel tones by holding an elastic 

 spring against the edge of a toothed wheel. 

 and he placed the vowels in the following 

 order — oa^ o, «, e, and /. In each case a 

 compound tone was produced which re- 

 tained the same pitch so long as the wheel 

 revolved at the same rate. By keeping 

 the wheel revolving at a uniform rate, and 

 at the same time changing the length of 

 the spring which was allowed to vibrate, 

 AN^illis found that the qualities of various vowels were imitated with 

 considerable distinctness. In 1837 Wheatstone,'' in a criticism of 



Willis, made some important sug- 

 gestions. In 1854: Grassmann' an- 

 nounced a theory as follows: The 

 vocal chords excite th(^, resonances 

 of the cavity of the moutlif the 

 tonality changes with the degree of 

 opening of the mouth ])y the devel- 

 opment of some of the harmonics 

 of the fundamental tone emitted by 

 the larynx. According to this view 

 the ])uccal cavity adds by its reso- 

 nance certain harmonics to the fundamental laryngeal sound. Grass- 

 mann classiiied the vowels according to the number of hat-monies 

 which they contained in the following ta])le: 



Fig. 21. 



Tracings obtainecl Vjy Her- 

 mann of vowel o. 



':m- 



Fig. 22. — Rojh'^'s Mpparatn.s for tlie analysis of 

 vowel-tones. 



-OH 



-II 

 .1 



«Wil]is: Caiii])ri(lge, Phil. Trans., 1829, vol. iii, p. 2:51; also Ann. .1. Pliys. u. 

 chem., Leipziji;, Bd. xxiv, p. 397. 



''AVheatstone, WestniinHter Review, October, 18;>7. 



''Grassmann: Uber die phy.sik. Natur <les Spraclileute, 1877; lie liad, liuwcvfr, iu 

 1854, enunciated his theorv in Ueljersicht der Aliustik u. der nieilein Optik. 



