rderline between the physiology of voice-production and the psychology
of song is a narrow one--whereof the above cure for stage-fright is but
another case in point.

CHAPTER V

THE PHYSIOLOGY AND PSYCHOLOGY OF VOICE-PRODUCTION

Above this chapter I might well have placed the following lines which
George Eliot wrote above Chapter XXXI. of "Middlemarch."

How will you know the pitch of that great bell,
Too large for you to stir? Let but a flute
Play 'neath the fine-mixed metal! Listen close
Till the right note flows forth, a silvery rill:
Then shall the huge bell tremble--then the mass
With myriad waves concurrent shall respond
In low, soft unison.

The lines telling of the great bell stirred by the note of a flute
played at the proper pitch suggest the moving power that lies in
sympathetic vibration. The first time a military body crossed the
Brooklyn Bridge, the spectators were surprised to hear the order given
for the soldiers to march out of step. They had expected to be thrilled
by the sight of a thousand men crossing the great structure in measured
tread, with band playing and colors flying. They did not know that the
structure, being a suspension bridge, might have been weakened and
possibly destroyed by the force of rhythmic oscillation. Yet the
accumulated force in the tramp of a thousand men is no greater than that
which lies in the sympathetic vibrations of a musical note. Every metal
structure has its note, and it is an old engineering saw that a huge
structure like the Brooklyn Bridge eventually could be destroyed by the
cumulative force of sympathetic vibration evoked by a musical instrument
constantly reiterating the note of the bridge.

Sound has three dimensions: pitch, loudness and timbre.

_Pitch_ depends upon the _frequency_ of vibrations. The more rapid the
vibrations, the higher the pitch.

_Loudness_ is determined by the _amplitude_ of the vibrations. As their
length or "excursion" increases, so does the sound gain in loudness.
Conversely, the diminution in the size of vibrations causes
corresponding decrease of loudness.

Differences in the _shapes_ of vibrations cause differences in quality
or _timbre_.

After voice has originated within the restricted limits of the larynx,
its power, its carrying quality is much augmented by the sympathetic
vibrations within the resonance cavities above the larynx. These include
the pharynx, nasal passages, mouth, bone cavitie