Many physiologists aver that ventriloquism is produced by speaking
during the inspiration of air. It is quite possible to articulate under
these circumstances, and the plan may be occasionally adopted; but the
practical experience of many performers prove that the general current
of utterance is, as in ordinary speech, during _expiration_ of the
breath.
Some think ventriloquism comprises a management of the echoes; but
echo only repeats what has been already spoken. Baron Mingon, a famous
ventriloquist, had an automaton doll with which he could apparently
converse. He thus describes his _modus operandi_: “_I press my tongue
against the teeth, and thus circumscribe a cavity between my left cheek
and teeth, in which the voice is produced by the air held in reserve in
the pharynx_. The sounds thus receive a hollow and muffled tone, which
causes them to appear to come from a distance.” The Baron says, “It is
essential to have the breath well under control, and not to respire
more than can be avoided.” Ventriloquists often experience fatigue in
the chest, and have attributed it to the slow expiration of the breath.
Some are often compelled to cough during the progress of exercitation.
To attain an exact and positive knowledge of the modifications of voice
specified as ventriloquism, it is important to be familiar with the
distinctions of the sounds uttered by the mouth; and to ascertain how
the organs act in producing those vocal modifications, it is necessary
to know how the breath is vocalized in all its distinctions of pitch,
loudness, and quality, by the ordinary actions of the vocal organs. In
ordinary language we speak of noise, of common sound, and of musical
sounds. A quill striking a piece of wood causes a noise, but striking
successively against the teeth of a wheel, or of a comb, a continued
sound, and if the teeth of the wheel are at equal distances, and the
velocity of the rotation is constant, a musical sound.
Phonation, or the production of voice, is a result of actions taking
place under two distinct classes of laws, namely: the ordinary
mechanical laws of acoustics, and the physiological laws of muscular
movement. The adjustment of the vocal mechanism to be brought into
operation by the current of air, is made by actions, under the latter
laws; and phonation is the result of the reaction of the mechanism
on the current of air by mechanical movements under the former laws.
Now the pitch of the voice essentially depends on the tension of the
vocal ligaments; the loudness on the extent of the excursion of these
ligaments in their vibrations; the duration on the continuance of the
vocalizing causes; the equality on the organization of the larynx,
and also on the form and size of the vocal tube. The form and size of
this tube can be altered in various ways. For instance, by dilating or
contracting the mouth; by contracting the communication between the
pharynx and mouth, so as to constitute them distinct chambers, or by
dilating the opening so as to throw them into one, which is chiefly
attained by movements of the soft palate, and by altering the form
of the mouth’s cavity, which is effected by varying the position of
the tongue. Each of these modifications of the vocal tube conveys a
peculiarity of quality to the voice, all, however, being local or
laryngeal sounds. Moreover, sounds can be produced in the vocal tube,
apart from the larynx. These, strictly speaking, are not vocal sounds,
though some of them may be of a definite and uniform pitch, while
others are mere noises, as rattling, whispering, gurgling, whistling,
snoring, and the like. Now, as everything audible comes under the
classes of noise, sound, or musical sound, and as each variety
originates in the vocal apparatus of man, it is obvious that _an
ordinary vocal apparatus is all that is required_ for the achievement
of the feats of ventriloquy.
A person in a house cannot judge by the noise of an approaching
carriage, with any certainty, whether it is coming from the right or
left. Thus it is in many other sounds. _But we judge the direction
sound has travelled from its source on reaching the ear._ The
ventriloquist indicates, either directly or indirectly, the direction
from which he wishes his audience to believe the sound is coming. Thus
he directly indicates it by words, such as, “Are you up there?” “He is
up the chimney,” “He is in the cellar,” “Are you down there?” &c. He
indirectly indicates it by some suggestive circumstance, as an action
or gesture, which is so skilfully unobtrusive and natural as to effect
its object without being discovered. Thus, when the ventriloquist
looks or listens in any direction, or even simply turns towards any
point, as if he expected sound to come thence, _the attention of an
audience is by that means instantly directed to the same place_.
Thus, before a sound is produced, the audience expect it to come in
the _suggested direction_, and the ventriloquist has merely by his
_adjustment of vocal loudness_, to indicate the necessary distance,
when a _misjudgment of the audience will complete the illusion which he
has begun_.
The effect which is produced on sound by its travelling from a
distance, is observed to be,--