, it was seen that the outflow of the breath in
tone-production is checked by the vocal cords, in accordance with
Pascal's law of fluid pressures. Another law of mechanics bearing on
this operation is now to be considered, viz., the law of the
transformation and conservation of energy.

The application of the law of the transformation and conservation of
energy to the operations of the voice is nicely illustrated by the
well-known candle-flame test of (supposedly) breath-control. To perform
this test the singer is instructed to practise the exercises for
breath-control while holding a lighted candle with the flame an inch or
two in front of the lips. According to the idea of the breath-control
advocates, the expired breath should escape so slowly, and with so
little force, that no current of air can be detected at the lips, the
expiration therefore does not cause the candle flame to flicker.

Describing the toneless breathing exercises to be practised with the
candle flame, Browne and Behnke say, "Let it be observed that the above
exercise is quite distinct from the well-known practice of _singing_
before a lighted candle, which is, comparatively speaking, an easy
matter." (_Voice, Song, and Speech_.) A very striking fact is stated
correctly by Browne and Behnke,--there is no current of air created at
the lips during tone-production. Of the truth of this statement the
reader may readily convince himself by trying this same experiment with
a candle flame, or even with a lighted match. Hold a lighted match just
in front of the lips and sing a powerful tone. The quality of the tone
is of no consequence so long as it be powerful. Just sing, shout, yell,
the louder the better. You will find that the flame is less affected
under these circumstances than by the quiet expiration of ordinary
breathing.

Considerable practice and close attention are required in order to hold
back the breath in toneless breathing exercises. Whereas in producing
any kind of powerful tone the breath normally creates no current of air
at the lips.

There is no reason for considering this experiment a test of correct
tone-production. It is impossible to produce a powerful tone of any
kind, good, bad, or indifferent, and at the same time to create an
appreciable current of air at the lips.

Needless to say, the breath-control theorists have entirely failed to
grasp the significance of the candle-flame experiment. Yet we have here
a demonstration