of light passing from that object, make that picture? May it not be that the eye has a power somewhat analogous to the reflection of a mirror; and that external objects pictured on the retina, are, in some incomprehensible manner, reflected to the mind?

CHAPTER XIV.

Further Proofs from the Senses.

87. The sense of hearing is even less understood than that of vision; the uses of the organs of this sense are more difficult to comprehend; and it is not easy to make known the little that is comprehended, by words, or even by the use of drawings.. It will be sufficient for the present purpose, that is to prove the certainty of design, or of means used to an end, to advert to a quality of the common air which every one is familiar with, viz. that by exerting the human voice through a common trumpet, it can be sent to a far greater distance than when committed to the air without using such an instrument. The ear has some, but a very slight resemblance to a trumpet inverted. That part which is visible, seems to be intended in men, and animals, to collect sound, and conduct it inward, until it strikes on a thin membrane, called the tympanum, drawn across the outward end of the barrel or drum of the ear; tympanum is from a Latin word meaning drum. Between this membrane and an interior one in the hollow of the ear, there are four very small bones which seem to connect the two membranes. The use of these bones, in conducting sound is not known; one of them is connected by one end with the tympanum, and with the second at the other end, and this with the third, and that with the fourth and this with the inner membrane, drawn across another space, and within or behind this membrane, is a cavity deeply encompassed with the bone of the skull, containing a liquid, wherein

the auditory nerve, (from audire, to hear), proceeding from the brain, developes itself, much in the same way as does the optic nerve in the eye.

88. To have the perception of hearing sound, it must pass through the ear to this nerve, aud through it the effect is made on the mind. When we consider what the variety, and the number, of sounds are, which must affect this organ, in the ordinary purposes of life, and its distinguishing power, and its nice adaptation to the end designed, we are left in no doubt as to the intelligence which its mere contrivance required. But however faithfully anatomical investigation may disclose the component parts of the ear, it does not, nor can any investigation which art or science has hitherto made, bring the least conception of the nature of hearing to our minds. How sound affects that organization, and how it communicates with the mind, is incomprehensible.

89. The commonly received theory of hearing is very unsatisfactory. Particles of air, it is said, being affected by some impulse given by the organs used in speaking, or any other sound-making agent, communicate that impulse to adjoining particles of air, and they to others, and so on, until those which are in contact with the tympanum affect it, and thus sound goes to the brain. That air is necessary to the conveyance of sound every where, above the surface of water; and that water is necessary to the conveyance of sound made in water, and that sound glides along the smooth surface of water to a greater distance than it can on the surface of the ground, every body knows. But that sound is nothing but an agitation of the air it is difficult to believe. When one is speaking to a numerous assembly in a large apartment, he may make himself distinctly heard, and understood, even in the most rapid and minute articulation of which he is capable, by those persons who are most remote from him. But no effort of his lungs would affect, in the least degree, the lightest substance which floats in the air, at one half, or perhaps one quarter, of that dis

tance. So one may make a violent agitation of all the air in a large apartment by swinging a door backwards and forwards, but he will make thereby no sound. Sound can be made to pass from one apartment to another, through a solid wall, and when the air on one side of it cannot receive any impulse from the air on the other. Sound passes through wood, metals, and other substances, with far greater rapidity than through air or water. And through some it cannot pass.

90. Is there then something in nature, hitherto unknown, which is sound; as there may be something, which is vision? That human ingenuity has gone no further as yet, in the philosophy of sound and vision, is no reproach to it. Looking back on its inventions and discoveries, it would be some reproach to it to assume, that it has attained its utmost limits on these subjects.

91. The other senses must be passed over with a few words. That of feeling seems to be diffused throughout the system. The sensation is always local, whether in the extremities, in the organs of sense, or in the brain itself. So also tasting and smelling are local. The connection between these and the mind is alike hidden from us. The only similarity between these three senses, and those of seeing and hearing is, that as to the three former, perception has a locality in the system, that is, feeling is every where, tasting is in the organs of taste, smelling is in the organs assigned to give that perception, but the organs of seeing and hearing give no organic sensation, and we only learn from experience that it is the eye that sees, and the ear that hears. The action of the eye, and of the ear, depends upon no volitions of our own. If they were physically touched by the objects of which they convey notice to the mind, as the other senses seem to be, would they not from their wonderful complication and delicacy of structure, soon wear out, and become unfit for their offices? Is there not something which may be called intellectual in the action of these two senses? But these are inquiries not

necessary to the present purposes, if they are deserving of any notice.

92. If the purpose in view, thus far, has been sufficiently accomplished, to make that purpose understood, it has been shown, that there is a created material universe, of which man constitutes a part. That he is curiously and wonderfully prepared and designed to act on this universe, and that it is, in like manner, prepared and designed to act on him. There is reason to believe, from what we know him to have been able to do in relation to this material system, that there is no part of it with which he cannot connect himself to some useful purpose. Surely this is true as to all things and beings on earth, to which he has access. It is even true as to the far distant luminaries of the firmament. He has made himself acquainted with the laws which govern them. He has made them, millions of miles from him as they are, minister to his necessities, his wants, and his pleasures. They make known to him the precise point on which he happens to be on the surface of his own little globe, the existence of which is perhaps unnoticed and unknown to the intelligent beings who may inhabit them. They have served him to enlarge his mind, to invent rules of science, and they have served him to elevate his conceptions, and to raise himself to that high station in the scale of being, mortal as he is, which permits him to know, and to adore, and to render his humble tribute to the infinite and awful MIND, of whom, and through whom, all things are ordained.

CHAPTER XV.

Proofs from Human Intellect.

93. We have endeavored to find man's place in the material world. We have next to consider him in his intellectual character. In this respect it will appear, that his material formation, and that of his

mind, have an intimate and necessary connexion. Whatever the mind may be, and in whatsoever manner it is connected with its material dwellingplace, it does not display its powers until it has been acted upon by the senses. This fact has led to the belief in the materiality of the mind, and has been the subject of many refined discussions. It is certain that the physical and mental action of one human being, is known to any other by and through the senses only. These truths force on us the necessity of considering the action of the senses in connexion with, and inseparably from, what is known of the qualities of the mind. This will be found to be at best a very limited knowledge.

94. The human mind has been the subject of many learned works. These have been given to the world at different periods. Each successive author has had the opportunity of studying the theories of his predecessors, and of adopting, modifying, disproving, or rejecting them, and of attempting to establish his own. It is not intended

to compare different systems, if the ability to do this could be assumed, nor to pronounce which of them should be received, nor which of them should be rejected. All of them are far too learned, and refined, for elementary instruction. It is proposed, as sufficient for the present object, to invite those who are of competent years to do it, to examine their own intellectual acts as the simplest and easiest, and perhaps, the most satisfactory mode of instruction.

95. No one knows how his earliest steps in the acquirement of knowledge were taken; but he knows what the fact is with his juniors, and he infers truly, that his own course must have been similar. It is thus known to every one, that in earliest infancy the human being is, of all animals, the most helpless: that months elapse before there is any apparent sensation, but that which arises from the want of food, or a sense of suffering. The eye and the ear are, for a long time, insensible, and when age enough is obtained to put these organs