great was his wonderment to find that, after a little practice he could
voluntarily remedy this squeezed position until it gradually disappeared
altogether, and with it the unpleasant quality of voice which had caused
him so much trouble.

The inherent quality of tone is reinforced by the co-vibrations of the
air in the resonance cavities, the greater fulness of the sound being
caused by the increased quantity of air which is set into vibration. The
slightest alteration in the shape of these cavities affects the quality
of vocal tone by altering the direction and size of the air columns.

There is for every tone an air column of a certain size which most
powerfully reinforces that tone; and every resonance cavity answers to
some particular note better than to others. Timbre in the voice depends
largely upon the echoing and re-echoing of these resonance chambers; and
it needs but little reflection to see that the shape given to the mouth
in pronouncing speech sounds--more especially vowel sounds, with all
their various shades--interferes more or less with the purity and
quality of tone. Hence the necessity in singing for modifying vowel
pronunciation to suit the various tones and pitches of the voice. Every
shade of vowel has a certain pitch of its own which is best produced by
certain positions of the mouth, tongue, and soft palate. It is,
therefore, necessary, carefully to shape the mouth so that, on notes of
different pitches, the configuration of the mould may be that which
gives the best quality of the particular vowel tone. There must be an
unimpeded passage for the voice from the larnyx to the lips, and this
cannot be obtained if the same vowel shades are maintained in song as in
speech. The vowels which require the greatest alteration in position of
the mouth are A, E, and U; E being quite the most difficult, because,
contrary to the opinion of some teachers who consider it the best for
forward production of tone, it keeps the sound farther back in the
throat than any other vowel, shutting it up and making the sound thin
and poor. Diligent practice before a mirror is necessary in order to
acquire the best position of the buccal resonance chamber; its
attainment will well repay the trouble taken, for not only will the
voice gain in timbre, in resonance, and in ease, but pronunciation will
become pure and clear.

The vowel "ah" is frequently chosen as the best one for vocalising,
because in its pronunciation it