inquiry, which we do not undertake to explain. We have before us the antecedent and the consequent, the affection of the organ of hearing by an outward impulse, and the new mental state within; but the reason of this invariable connection in two things, that are entirely distinct and different, is a matter beyond our limited comprehension.

§. 65. Varieties of the sensation of sound.

The sensations, which we thus become possessed of by the hearing, are far more numerous than the words and the forms of speech, having relation to them in different languages, would lead us to suppose. It will help to illustrate this subject, if we recur a moment to the sense of TASTE. The remark has somewhere been made to this effect, and probably with much truth, that if a person were to examine five hundred different wines, he would hardly find two of them of precisely the same flavor. The diversity is almost endless, although there is no language, which distinguishes each variety of taste by a separate name. It is the same in respect to the sensations of sound. These sensations exhibit the greatest variety, although the differences are too minute to be separately and distinctly represented by language.

These views will appear the less objectionable, when it is remembered, that sounds differ from each other both in the tone, and in the strength of the tone. It is remarked by Dr. Reid, that five hundred variations of tone may be perceived by the ear, also an equal number of variations in the strength of the tone; making, as he expressly informs us, by a combination of the tones and of the degrees of strength, more than twenty thousand simple sounds, differing either in tone or strength.

In a perfect tone, a great many undulations of elastic air are required, which must be of equal duration and extent, and follow each other with perfect regularity. Each undulation is made up of the advance and retreat of innumerable particles, whose motions are all uniform in direction, force, and time. Accordingly there will be varieties also and shades of difference in the same tone, arising from the position and manner of striking the sonorous body, from the constitution of the elastic medium, and from the state of the organ of hearing.

Different instruments, such as a flute, a violin, and a bassviol may all sound the same tone, and yet be easily distinguishable. A considerable number of human voices may sound the same note, and with equal strength, and yet there will be some difference. The same voice, while it maintains the proper distinctions of sound, may yet be varied many ways by sickness or health, youth or age, and other alterations in our bodily condition, to which we are incident.

§. 66. Manner in which we learn the place of sounds.

It is a fact worthy of notice in respect to sounds, that we should not know, previous to all experience on the subject, whether a sound came from the right or left, from above or below, from a smaller or a greater distance. And this will appear the less surprising, when we remember that the undulations of air are always changed from their original direction by the channels and the windings of the ear, before they strike the tympanum. Abundant facts confirm this state

ment.

Dr. Reid mentions, that once, as he was lying in bed, having been put into a fright, he heard his own heart beat. He took it to be some one knocking at the door, and arose, and opened the door oftener than once before he discovered, that the sound was in his own breast. Some traveller has related, that when he first heard the roaring of a lion in a desert wilderness, not seeing the animal, he did not know on what side to apprehend danger, as the sound seemed to him to proceed from the ground, and to enclose a circle, of which he and his companions stood in the centre.

It is by custom or experience, that we learn to distinguish the place of things, and, in some measure also, their nature, by means of their sound. It is thus that we learn, that one noise is in a contiguous room, that another is above our heads, and another is in the street. And what seems to be an evidence of this is, that when we are in a strange place, after all our experience, we very frequently find ourselves mistaken in these respects.

If a man born deaf were suddenly made to hear, he would probably consider his first sensations of sound, as originating wholly within himself. But in process of time we learn not

only to refer the origin of sounds to a position above or below, to the right or left; but to connect each particular sound with a particular external cause, referring one to a bell as its appropriate external cause, another to a flute, another to a trumpet.

§. 67. Application of these views to the art of ventriloquism.

We are naturally led to make a few remarks here in explanation of VENTRILOQUISM, a well known art, by which persons can so modify their voice, as to make it appear to their audience to proceed from different objects, distances, and directions. There is no peculiarity of structure in ventriloquists, as is often supposed; except that the capacity of the chest and the lungs is sometimes found to be greater than usual. It is also true, that the power and activity of the muscles, connected with the organs of speech and with the chest and lungs, is considerably increased by frequent exercise. Nevertheless the great natural requisite on the part of the ventriloquist is to be able to mimic sounds; and he will be likely to succeed nearly in proportion to his skill in this particular. The secret then of his acoustic deceptions, supposing him to be capable of exact imitation, will be sufficiently understood by referring to the statement maintained in the preceding section, viz. That, previous to experience, we are unable to refer sounds to any particular external cause.

The sound itself never gives us any direct and immediate indication of the place, or distance, or direction of the sonorous body. It is only by experience, it is only by the association of place with sound, that the latter becomes an indication of the former. Now supposing the ventriloquist to possess a delicate ear, which is implied in his ability to mimic sounds, he soon learns by careful observation the difference, which change of place causes in the same sound. Having in this way ascertained the particular modulation of sound, which, in accordance with the experience of men and the associations they have formed, are appropriate to any particular distances, direction, or object, it is evident, whenever he exactly or very nearly imitates such modulations, that the sounds must appear to his audience to come from such distance, object, or direction.

One part of the art, however, consists in controlling the

attention of persons present, and in directing that attention to some particular place by a remark, motion, or some other method. If, for instance, the sound is to come from under a tumbler or hat, the performer finds it important to have their attention directed to that particular object, which affords an opportunity for the exercise of all those associations, which they have formed with any sound coming from a very confined place. All, then, that remains for him to do, is, to give his voice a dull modulation and on a low key, which we know from our experience to be the character of confined sounds, Then there seems to be a voice speaking under a tumbler or hat; and if any person should, either intentionally or unintentionally, lift these articles up, the ventriloquist immediately utters himself more distinctly and freely, like a person who had been very much confined, on being readmitted into the free and open air. It is also necessary, when his face is towards his auditors, that he should make use chiefly of the muscles of his throat; an outward and visible moving of the lips would much weaken the deception.

§. 68. Uses of hearing and its connection with oral language. Although, as in the cases just mentioned, the artifices of men may sometimes impose upon this organ and lead its decisions astray, it is one, in the ordinary calls for its exercise, of exceeding value. One of the distinguished benefits of the sense of hearing is, that, in consequence of it, we are enabled to hold intercourse with each other by means of spoken language, without which the advancement of the human mind must have inevitably been very limited. It is by means of speech, that we express our feelings to the little company of our neighbors and our own family; and without it this pleasant and cheering intercourse must be almost entirely suspended. Not limited in its beneficial results to families and neighborhoods, it has been the medium of the transmission of thought from age to age, from generation to generation. So that in one age has been concentrated the result of all the researches, the combination of the wisdom of all the preceding.

"There is without all doubt," it has been observed, “a chain of the thoughts of human kind, from the origin of the

world down to the moment at which we exist, a chain not less universal than that of the generation of every being, that lives. Ages have exerted their influence on ages; nations on nations; truths on errors; errors on truths."

Whether oral language was an original invention of man, or whether in the first instance it was a power bestowed upon him by his Creator and coeval with the human race, the ear must in either case have been the primary recipient.The faculty of speech so necessary and so beneficial could not have existed, either by invention or by communication, without the sense of hearing. And hence it happens, that all those, who are born deaf, are without speech. Their inability to speak is not in general the result of a defect in the organs of speech, but because they cannot hear others, and thus imitate the sounds they utter.

CHAPTER FIFTH.

THE SENSE OF TOUCH.

§. 69. Of the sense of touch and its sensations in general. WE are next to consider the sense of TOUCH. The principal organ of this sense is the hand, although it is not limited to that part of our frame, but is diffused over the whole body. The hand principally arrests our attention as the organ of this sense, because being furnished with various articulations, it is easily movable by the muscles, and can readily adapt itself to the various changes of form in the objects, to which it is applied.

The senses, which have hitherto been examined, are more simple and uniform in their results than that of the touch. By the ear we merely possess that sensation, which we denominate hearing; we have the knowledge of sounds, and that is all. By the palate we acquire a knowledge of tastes, and by the sense of smelling we become acquainted with the odors of bodies. The knowledge, which is direct