December 26, 1901] 



NA TURE 



183 



eyes of deaf mutes images of the movements of speech which 

 they are urged to imitate. 



It is interesting, in the next place, to trace the efforts that 

 have been made by physicists and physiologists to record the 

 pressures produced by sound waves and more especially those of 

 the voice. In 185S, Leon Scolt invented the phonautograph, 

 seen in Fig. 5. In its first form this instrument gave very im- 

 perfect tracings, but it is of great interest as being the forerunner 



R»pe 



ViVla 



P n 

 V 1 

 M 1 



P. n. 

 V. 1. 

 M. 1. 



P n 

 V 1 

 .M 1 



L 



V 



» >•. .. .VUWVMAjVWWWVVW, 



Fig. 2.— Tracings of nasal, laryngeal and labial movements in the pronunciation of various 

 phones. 



but light lever having its fulcrum at the edge of the membrane 

 while the power was applied from the centre of the membrane. 

 This gave more accurate tracings, that is to say, tracings that 

 indicated with more precision the variations of pressure on the 

 membrane. Examples are given in Figs. 6, 7, and 8. 



In Fig. 6 at A the membrane is at rest : at B the lever is 

 raised by the sudden emission of the consonant h, and this is 

 succeeded by the prolonged vibration of the vowel e. Fig. 7 

 gives a different picture for e b ; A is the 

 vowel e ; B the closure of the lips at the 

 beginning of the consonant ; this clo.sure 

 lasts during c, and D is due to the elas- 

 ticity of the air compressed in the mouth. 

 In Fig. 8, (5 t; /), we find the elements of 

 Figs. 6 and 7. By the logograph the con- 

 sonantal sounds were alone depicted, the 

 records of the vowels being very imperfect. 



There was still a demand for a recorder 

 of greater accuracy. Schneebeli,' in 1S78, 

 devised an instrument seen in Fig. 9. 

 From the centre of a parchment membrane 

 arises a thin but rigid steel plate ; attached 

 to this, near the point, is another steel 

 plate passing horizontally from the edge of 

 the metallic ring carrying the membrane. 

 The movements of the membrane are five 

 times increased in amplitude, while the 

 extreme lightness of the lever reduces to a 

 minimum the effects due to inertia. Ex- 

 amples of curves obtained by this method 

 are shown in Fig. 10. 



A very sensitive apparatus, termed the 

 Sprachzeichner, has also been introduced 

 by Hensen- for recording the delicate 

 vibrations of a membrane. It will be 

 readily understood by referring to Figs, ir, 

 1 2 and 13. Valuable observations have been 

 made with the aid of this instrument by 

 Wendeler," on consonant sounds, by Mar- 

 tens,'' on vowels and diphthongs, and by 

 Pipping,'' on vowels. 



Such are some of the mechanical con- 

 trivances that have been devised for re- 

 cording the movements of a membrane. 

 None are free from error, however delicate 

 they may seem to be, owing to the inertia 

 of the parts, and consequently other arrange- 

 ments were demanded. In 1S62'' Rudolph 

 Konig introduced his well-known method 

 of showing the movements of membranes 

 by manometric flames. The apparatus is 

 now so well known as to require no detailed 

 description. Gas is led by a tube into a 

 small capsule of wood, the cavity of which 

 is divided by a thin membrane (Fig. 14, .\). 

 The gas passes into the right half of the 

 cavity and escapes into a small burner, 

 where it is lit. If sound waves are diverted 

 by a small conical resonator into the left 

 half of the capsule the membranous par- 

 tition vibrates, there are alternations of com- 

 pression and of rarefaction in the gas on the 

 right side, and the flame is agitated, moving 

 upwards and downwards with each vibra- 

 tion. The method of Wheatstone of disso- 

 ciating the flames by a rotating mirror is 

 then employed, and a sinuous ribbon is 

 seen in the mirror. The ribbon is cut verti- 

 cally into teeth, some larger, some smaller. 

 The larger, less frequent, correspond to the 



1 



'i r 



of the phonograph. It was much improved by Rudolph Kijnig, of 

 Paris. Donders,' in 186S, w.as the first to use the instrument 

 in the investigation of vowel-tone. Then came the logograph of 

 Barlow^' in 1876, which was a membrane furnished with a rigid 



1 Donders : " Zur KlanEfarbe der Vocale " (.Ann. derPhysik uiid Chemic, 

 t86SV 



- Barlow : "On the Articulation of the Human Voice, as Illustrate by 

 the Logograph "(rraKj. Roy. Soc. 1S76). 



He 



'Ueber d 



1 SociitiS des Scienc 

 5 Avril et 20 Novembi 



Schrift von Schallbewegungen 



Naturelles de Neuchatel. 

 [878. 



(Ziits. far 



Schallbewegungen einiger Kon- 



eler : " Ein "Versuch iiber 

 (Zeits.fUr Bioloje, 1886). 

 ^ Martens : " Ueber des Verhalten von Vocalen und Diphtongen in 

 Zesprocbenen 'Worten " (Zeits. fur BMogk, 1889). 



5 Pipping: "Zur Klangfarbe der Gsi\mgenVoc^\e" (Zeits. fur Biohgie, 

 1890); "Ueber die Theorie der Vocale" (Aria Socictatis ScUntuirnm 

 HeUingfors, 1894). 

 I! Konig: " yuelques Experiences d'Acoustique {Paris, 1882). 



NO. 1678, VOL. 65] 



