438 AN AMERICAN TEXT- BOOK OF PHYSIOLOGY. 



group 2. They may be divided into labio-dental JricfionaU, f (without voice) ; 

 r, w (with voice) ; the lingual friciionah 8, fh (as in them); sh, ch soft (with- 

 out voice); ~, / (with voice). The sound of h may be regarded as due to the 

 vibration of the separated vocal cords. It is peculiar, however, in appearing 

 to be formed in any part of the vocal chamber* when it is formed the mouth 

 parts take on no peculiar position, but assume that of the vowel following the 

 //, as hark, hear, etc. 



