a branch stream of
breath, however small, must be forced back, behind and above the
pillars, first into the nose, later into the forehead and the cavities
of the head. This forms the overtones (head tones) which must vibrate
with all tones, even the lowest. These overtones lead over from the
purest chest tones, slowly, with a constantly changing mixture of both
kinds of resonance, first to the high tones of bass and baritone, the
low tones of tenor, the middle tones of alto and soprano, finally, to
the purest head tones, the highest tones of the tenor-falsetto or
soprano. (See the plates.)

The extremely delicate gradation of the scale of increase of the
resonance of the head cavities in ascending passages, and of increase
of palatal resonance in descending, depends upon the skill to make the
palate act elastically, and to let the breath, under control of the
abdominal and chest pressure, flow uninterruptedly in a gentle stream
into the resonating chambers. Through the previous preparation of the
larynx and tongue, it must reach its resonating surfaces as though
passing through a cylinder, and must circulate in the form previously
prepared for it, proper for each tone and vowel sound. This form
surrounds it gently but firmly. The supply of air remains continuously
the same, _rather increasing than diminishing_, notwithstanding the
fact that the quantity which the abdominal pressure has furnished the
vocal cords from the supply chamber is a very small one. That it may
not hinder further progression, the form must remain elastic and
sensitive to the most delicate modification of the vowel sound. If the
tone is to have life, it must always be able to conform to any vowel
sound. The least displacement of the form or interruption of the
breath breaks up the whirling currents and vibrations, and
consequently affects the tone, its vibrancy, its strength, and its
duration.

In singing a continuous passage upward, the form becomes higher and
more pliant; the most pliable place on the palate is drawn upward.
(See Plate A.)

When I sing a single tone I can give it much more power, much more
palatal or nasal resonance, than I could give in a series of ascending
tones. In a musical figure I must attack the lowest note in such a way
that I can easily reach the highest. I must, therefore, give it much
more head tone than the single tone requires. (Very important.) When
advancing farther, I have the feeling on the palate, above an