[Illustration: FIG. 57 (Beaunis). Shows the relative position of parts in sounding _I_. In sounding _E_ the position is a good deal like that for _I_.] When sounding _[=i]_ (as in _mine_) the cavity of the mouth behind resembles a small-bellied flask with a long, narrow neck, the larynx is at its highest, and the lips assume a position much as in the case of _[=e]_; between the hard palate and the back of the tongue there is only a narrow passage--a mere furrow. The pitch of this vowel is also high. It is thus seen that every vowel has its characteristic quality and pitch, the order as regards the latter being from below upward, _u_, _o_, _a_, _[=a]_, _e_, _i_. That the mouth cavity really can act as a resonance-chamber can be easily demonstrated by holding a small vibrating tuning-fork before the open mouth, and varying the shape and size of the cavity till the sound of the fork is observed to be suddenly increased in volume. The cavity then is a resonance-chamber for the fork, and thus intensifies its sound; in other words, the air in the mouth cavity vibrates in harmony with the tuning-fork. To demonstrate in a simple manner that each vowel has its own pitch, the mouth cavity is put into the form usual in sounding the vowel, and the finger is filliped against the cheek, when a tone answering in pitch to that of the vowel in question results. The demonstration is easier with the lower-pitched, broader vowels, but the correctness of the order of the pitch mentioned above can thus be shown to be established. Some very important principles for the speaker and singer hinge upon the above-mentioned facts. It follows, for example, that it is impossible to give a vowel its _perfect_ sound in any but one position of the mouth parts, so that for a singer to utter a word containing the vowel _[=u]_ (_oo_) at a high pitch is a practical impossibility. The listener may know what syllable is meant, and overlook the defect either from habit or from an uncritical attitude, but composers of vocal music should bear such facts in mind and not impose impossibilities on singers. At the same time, the vocalist, in order to satisfy a modern audience, is obliged to sound every word and every syllable as correctly as possible, even if the tone suffer somewhat thereby. It is wonderful how fully the best poets have, with the insight of genius, adapted their words (vowels) to the ideas they wish to convey, and had all composers of vocal music done the same, the path of the singer would not have been strewn with so many thorns. The difficulties in the case of the speaker are similar, but less marked, as his range is so much more limited as regards pitch. [Illustration: FIG. 58 (Beaunis). Shows the relative position of the parts in sounding _OU_.]