394 THE POPULAR SCIENCE MONTHLY. 



current from the lungs or from any other source. That this is the 

 case is shown by certain decisive and very interesting experiments. 

 On opening the mouth and adjusting the lips for the pronunciation 

 of a given vowel (though without uttering the slightest sound), the 

 vowel may be rendered sonorous by placing in front of the mouth a 

 vibrating tuning-fork. This method was first applied by Helmholtz. 

 The same result may be obtained by bringing in front of the open 

 mouth, through a tube with narrow terminal orifice, a current of 

 air from a pair of bellows. This plan originated with M. Konig. 

 Thus it is seen that the various sounds known as vowels depend 

 simply on the form of the resonating cavities, the pharynx and 

 the mouth. 1 When these cavities alone are in action, the voice is 

 aphonic, whispering ; it is sonorous when the vocal cords vibrate. 

 For a long time it was held by physiologists that vowels pronounced 

 even in a whisper come from the glottis ; precise information concern- 

 ing these phenomena is of very recent date. 



The number of vowels is generally restricted to five, six, or seven ; 

 these may be regarded as natural types, being found in nearly all 

 languages. But, in addition to them, there are intermediate vowels, 

 and a multitude of vowel combinations, so great is the power of 

 modification possessed by the buccal cavity. Then there are nasal 

 intonations (very abundant in the French language) produced by de- 

 pressing the velum palati. A language might consist only of vowels, 

 says Max Mtiller, and indeed this is very nearly the case with some 

 of the Polynesian dialects. 



Most languages possess aspirates of more or less harshness. In 

 French they are very few and weak, but in German they are frequent 

 and strong, while in Arabic they are specially forcible. Aspiration 

 requires the action of the glottis ; the orifice is reduced for an instant, 

 and the air, arrested by this obstacle, in issuing through the narrow 

 slit, produces a sound of something brushing against the vocal cords. 

 The aspirate is sometimes sonorous in the Semitic languages. 3 The 

 guttural sounds of the Arabs used to be the subject of grave discus- 

 sions among linguists, but Czermak put an end to these controver- 

 sies. That learned physiologist, having fallen in with an Arab, 

 availed himself of the opportunity to examine with the laryngoscope 

 an organ capable of producing a sonorous aspirate. The whole 

 matter was now plain : it was found that, while the epiglottis was 

 depressed, the vocal cords were in close contact ; the orifice being 

 thus absolutely closed, the current of air driven against the roof 

 produces a vibration beneath the glottis, in the fissure of the larynx. 



The sounds produced in the buccal cavity are broken up on meet- 



1 When we pronounce the vowels a, e, i (pronounced ah, eh, ee), the vertical diame- 

 ter of the pharyngo-buecal cavity is diminished, while its transverse diameter is increased ; 

 it is exactly the contrary with the vowels o, ou, and u (pronounced oh, oo, w). 



9 It is the din of the Arabic. 



