332 ANALYTIC ORTHOGRAPHY. 
342. Vowels are not musical sounds, these being made by the varying tension of the 
vocal ligaments, the tension for the vowels seeming to vary but little, except in song. 
But as the vowels depend upon the varying capacity of the mouth and pharynx, and as 
this would modify musical tones, there is an affinity between the two. 
343. Vowels are related to the musical scale of the cavity of the mouth, as determined 
by the jewsharp, or in whistling, which, in the same person, have a different compass 
from the song notes of the glottis; and as the whistling compass comprehends about two 
octaves, the speaking compass may be assumed as the same. ‘his is the proper basis for 
a comparison of vowel and musical pitch. 
344. In the vowel mechanism, although most of the vowels may be produced without 
exhibiting the more obvious changes in the organs accompanying them, yet their 
production in the natural mode is accompanied by certain conformations which are useful 
as collateral indicators. These affect the lips, jaw, tongue, and larynx, the two latter 
receding and advancing a little to enlarge or diminish the vocal tube or cavity, and of 
this the tongue is the index. Thus, the advance of the tongue to the teeth in I, E, 
shows a reduced vocal cavity, whilst its withdrawal in A, O, indicates its enlargement. 
By this criterion, of the vowels up, at, the former is placed nearer to A, although at is by 
many considered as a kind of A. 
345. From the opening of the lips by the retraction of the lateral angles required for I, 
to their closure for U, there is a gradual series of changes, the principal steps of which 
correspond with I, EH, A, O, U. Of these, I is, in musical phrase, the highest, the vocal 
cavity being diminished by closure, and its length curtailed by contracting the angles of 
the lips. 
346. The jaws open gradually as the lip opening is narrowed from I through E to A (or 
if this is not sufficiently open, to awe,) when they close towards O and U. But Tschnir- 
schnitz makes the jaw opening continue from I to U; and we can unite the jaw position 
of awe to the lip position of O or U, giving rise to sounds which may occur among such as 
are described in books as “o approaching u,” or “‘« approaching 0.” 
347. There is this difficulty in determining the vowel by the jaw opening, that the same 
vowel is not restricted to a particular opening. Thus add requires a smaller opening than 
A, yet A can be made with the opening of add, which may be made with the external 
aperture of I; but in both cases the additional space required is secured in the pharynx, 
as proved by the retraction of the tongue. If, therefore, we pass up the vowel scale from 
A to I, or down from A to U, without opening sufficiently for A at the commencement, 
we shall find the mouth shut at the extremes of the scale. 
348. In measuring the jaw aperture (by means of a graduated wedge inserted between 
