CHAP, vii.] SOME SPECIAL MECHANISMS. 1097 



tially noises generated in the larynx itself. These names are use- 

 ful for a general broad classification ; the term dental however is 

 used to include consonants which are formed by the tongue in 

 relation to, not the teeth, but the front part of the hard palate ; 

 hence it is to that extent open to objection. There are also 

 other classifications into which we cannot enter here. 



682. When the various languages of the world are exam- 

 ined the number of consonants, that is to say of sounds used in 

 speech and having the characters on which we are dwelling, is 

 found to be very large; and concerning the nature and mode 

 of formation of many of them much discussion has taken place. 

 We must content ourselves here with very briefly indicating the 

 chief facts concerning the mode of formation of the most impor- 

 tant and common. 



The group of consonants represented by M, N, NG, are very 

 closely allied to vowels. In each of these as in a vowel the 

 larynx is thrown into vibrations ; but instead of the vibrations 

 passing out by the mouth through a passage which has assumed 

 a form belonging to this or that vowel, the passage to the mouth 

 is closed, and the vibrations find their way out through the nasal 

 cavity which acts as a resonance chamber. When a vowel is 

 sounded the soft palate either completely shuts off the nasal 

 cavity from the vowel chamber, or at least offers such resistance 

 that an insignificant proportion of the expiratory blast passes 

 into the nasal cavities. A vowel may be sung powerfully, and 

 yet a flame exposed to the nostrils only will shew no movements ; 

 in the case at least of some vowels however, a piece of cold pol- 

 ished steel will become dim, shewing that some air is passing 

 through the nostrils. When the communications between the 

 nasal and pharyngeal cavities are sufficiently free, and the other 

 conditions are favourable for the nasal cavities to act as a reso- 

 nance chamber, the vowel sounds are apt to take on a nasal char- 

 acter; and this occurs more readily when the vowel is said than 

 when it is sung. In the group of consonant*? in question the 

 nasal cavities become all important, the passage through the 

 mouth being blocked. In M the passage is closed by shutting 

 the lips, in N by the application of the tongue to the front of 

 the hard palate and upper teeth, in NG by the application of the 

 tongue to the soft palate. 



While in the above group no new vibrations are added to the 

 laryngeaL vibrations, in the ordinary L which like them is based 

 on laryngeal sounds, new vibrations, constituting a noise, are 

 added. The passage is not completely, only partially closed ; the 

 front of the tongue is pressed against the hard palate in sueh a 

 way that the passage is blocked in the middle but the air escapes 

 through narrow eliannels on each side. It is the noise caused by 

 the rush of air through these narrow spaces which added to the 

 voice produces the sound we distinguish as L. In certain forms 



