PERCEPTION OF TIMBRE. ANALYSIS OF VOWELS. 



E 



the entrance of the air-chest allows all the opened pipes to sound together. The 

 two rows of pipes make possible three degrees of tone-intensity, namely loud tones, 

 when both rows sound; moderately loud, when the open pipes sound; and weak, 

 when the stopped pipes alone sound. The formation of the vowels by this ap- 

 paratus is not so satisfactory as that by the tuning-forks, because the pipes do 

 not yield simple tones, but contain several weak (especially the uneven) overtones. 

 Moreover, the graduation of tone-intensity cannot be made as fine as with the 



resonators of the tuning-forks. 

 However, several of the vowels 

 can be beautifully reproduced. 

 They always sound the best 

 when they are quite short. Thus, 

 a good A is produced by b and b 1 

 weak, f n moderately strong, b 11 

 strong, d in weak and f ni moderately 

 strong. U is produced by B strong, 

 and b moderately strong. Deep 

 O = B and b moderately strong, f 1 

 and b 1 strong, with f 11 weak. A high 

 O is produced by b 1 weak, d 11 mod- 

 erately strong, f n and b 11 strong, d in 

 and f 111 weak. The other vowel- 

 sounds are produced imperfectly: 

 E = d 11 weak, with b 11 , d 111 , a 111 strong. 

 A = b 1 , f 11 , b 11 weak, d 111 , f" 1 moder- 

 ately strong, a 111 flat strong and 

 a 111 moderately strong. O = b 1 weak, 

 f 11 , b 11 strong, f m weak, b m , c iv , d iv 

 moderately strong. U = f 1 , f 11 'weak, 

 f ni , c iv strong. I cannot be produced. 

 The highest pipe d iv yields approxi- 

 mately the character of I. Similarly 

 the stopped pipe B yields an obscure 

 U and the open B a rather clearer U. 

 According to the foregoing con- 

 siderations, the vowels, being com- 

 posed of a fundamental tone and 

 overtones, must have definite vibra- 

 tion-curves. These may be demon- 

 strated in various ways. If a vowel 

 be spoken against a delicate glass 

 membrane closing the extremity of 

 a hollow cylinder, at whose center 

 is a fine curved style, applied to a 

 cylinder covered with a layer of 

 paraffin-wax and capable of revolv- 

 ing uniformly and of being displaced 

 laterally, the style will trace the 

 vowel-curve on the layer of wax. 

 If, now, a small point connected 

 with the membrane is allowed to 

 run in the groove traced by the 

 style, the resulting vibrations of the 

 membrane will reproduce the sound 

 (Edison's phonograph). Enlarged 

 curves of the sound-impressions 

 may be obtained by transmitting 



the impressions on the cylinder to a suitable apparatus. The vowels yield the 

 same sound only when the rapidity of revolution of the cylinder remains the same. 

 If on the other side of such a membrane, there is a small, closed gas-chamber, 

 from which a gas-burner passes, a characteristic tracing of the vibrating flame 

 can be obtained in a rotating mirror when the vowel is produced (Fig. 328). 

 Nagel and Sawojloff made use of the tympanic cavity and the tympanic mem- 

 brane for this purpose gas being introduced into the tympanic cavity of a fresh 







U 



FIG. 328. Flame Pictures and Phonautographic Tracings 

 of the Vowels. The vowels were sung in the key of C' 

 (= 256 vibrations in the second). The measure a b 

 shows the height of the flame at rest. The curves 

 traced below are registered by the phonautograph. 



