284 PLEASANT WAYS IN SCIENCE. 



But the vowel sounds are, after all, combinations and 

 modifications of musical tones. It is otherwise with con- 

 sonantal sounds, which, in reality, result from various ways 

 in which vowel sounds are commenced, interrupted (wholly 

 or partially), and resumed. In one respect this statement 

 requires, perhaps, some modification a point which has not 

 been much noticed by writers on vocal sounds. In the case 

 of liquids, vowel sounds are not partially interrupted only, as 

 is commonly stated. They cease entirely as vowel sounds, 

 though the utterance of a vocal sound is continued when a 

 liquid consonant is uttered. Let the reader utter any word 

 in which a liquid occurs, and he will find that while the 

 liquid itself is sounded the vowel sounds preceding or 

 following the liquid cease entirely. Repeating slowly, for 

 example, the word " remain," dwelling on all the liquids, we 

 find that while the "r" is being sounded the "e" sound 

 cannot be given, and this sound ceases so soon as the " m " 

 is sounded ; similarly the long " a " sound can only be 

 uttered when the " m " sound ceases, and cannot be carried 

 on into the sound of the final liquid " n." The liquids are, 

 in fact, improperly called semi-vowels, since no vowel sound 

 can accompany their utterance. The tone, however, with 

 which they are sounded can be modified during their 

 utterance. In sounding labials the emission of air is not 

 stopped completely at any moment. The same is true of 

 the sibilants s, z, sh, zh, and of the consonants g, j, f, v, th 

 (hard and soft). These are called, on this account, continuous 

 consonants. The only consonants in pronouncing which 

 the emission of air is for a moment entirely stopped, are the 

 true mutes, sometimes called the six explosive consonants, 

 b, p, t, d, k, and g. 



To reproduce artificially sounds resembling those of the 

 consonants in speech, we must for a moment interrupt, 

 wholly for explosive and partially for continuous consonant 

 sounds, the passage of air through a reed pipe. Tyndall 

 thus describes an experiment of this kind in which an 

 imperfect imitation of the sound of the letter " m " was 



