disposal of every individual. With this introduction to the subject I will
pass on to give a detailed description of the instrument of the voice.

[Footnote A: Sense of movement.]




THE VOCAL INSTRUMENT


A distinction is generally made in physics between sound and noise. Noise
affects our tympanic membrane as an irregular succession of shocks and we
are conscious of a jarring of the auditory apparatus; whereas a musical
sound is smooth and pleasant because the tympanic membrane is thrown into
successive periodic vibrations to which the auditory receptor (sense organ
of hearing) has been attuned. To produce musical sounds, a body must
vibrate with the regularity of a pendulum, but it must be capable of
imparting sharper or quicker shocks to the air than the pendulum. All
musical sounds, however they are produced and by whatever means they are
propagated, may be distinguished by three different qualities:

(1) Loudness, (2) Pitch, (3) Quality, timbre or klang, as the Germans call
it.

Loudness depends upon the amount of energy expended in producing the sound.
If I rub a tuning-fork with a well-rosined bow, I set it in vibration by
the resistance offered to the rosined hair; and if while it is vibrating I
again apply the bow, thus expending more energy, the note produced is
louder. Repeating the action several times, the width of excursion of the