Page images
PDF
EPUB

living creatures. It is not the object of any of the other senses. It cannot be perceived either by touch, taste, smell, or hearing; yet its properties are of essential importance to animal life. A camera obscura* is therefore bestowed on living beings, consisting of a small hole or opening in an opaque substance, through which, by means of a transparent medium, the rays of light are transmitted; a finely formed lens, which collects these rays, and concentrates them; and a sheet or retina, on which they fall at the proper focal distance, creating an exceedingly minute, but most complete and accurate, representation of external objects.

nature.

This combination, so obviously artificial, forms an optical instrument, at once complete of its kind, and differing in its construction from any thing else in organized The contrivances which constitute the lens and the retina, are peculiarly striking. The former is constructed with a most perfect and minute attention to the laws of optics; the latter is a singular and beautiful piece of workmanship, being an exceedingly delicate network of nerves, curiously interwoven, and ending in a nerve, which makes its passage to the brain. Here the mechanism is lost human ingenuity can trace it no further; because it is here that the mysterious and inscrutable principle occurs, which connects mind with matter, and conveys ideas of material objects to the sentient and reasoning powers. But up to this point, the contrivance is distinct and admirable. There is a mutual

:

adaptation between the eye and the properties of light, which clearly exhibits benevolent intention. The rays reflected from all surrounding objects, under the various modifications I have mentioned, are received into every eye that is turned to them, and give rise, in the mind, to the various ideas of light and shade, of shape and color, of distance and nearness, of beauty and deformity; and thus disclose many fields of useful knowledge, which would otherwise have been shut, and unfold sources of exquisite and varied enjoyment, which would otherwise

* The eye was adverted to, under this name, in Winter,' p. 102.

have been excluded; while they afford a theatre of exertion, without which the necessaries of life could not have been procured, and almost all the varieties of animated existence must instantly have perished. "If this does not prove appropriation," says Paley, after taking a similar view, I desire to know what would prove it."

The adaptations between the ear of animals and the air, are not less remarkable. We cannot so distinctly trace the uses of the various parts of the ear, as an instrument of sound, as we can trace those of the eye; but we can observe enough to discover, that they are no less complex and artificial; and, at all events, they equally answer the intended purpose. We are surrounded with an elastic and fluid medium, in which impulses create vibrations. These vibrations are scarcely perceptible to any of the other senses, and, if they were, could be of very little utility; but the ear is bestowed, and is made capable of receiving such impressions from these vibrations, as are productive of the highest advantages. If any person will attend to the various uses of sound, he will at once perceive of what importance to animal existence is the possession of an organ, by which it is perceived. To the inferior animals, it is that which warns them of danger; which attracts them to each other; which assists them in procuring their natural food; which is the medium of expressing their desires or aversions, their satisfaction or anger, their terror, their distress, their joy, or their sense of safety. Perhaps it may sometimes be the means of even more extensive communications between individuals of the same species.

To man, it serves all the purposes we have stated, and much more. Air can be shaped into words," and convey articulate sounds to the ear, which form a most wonderful and important system of mutual communication, and contribute, in an amazing degree, to the happiness and improvement of the human race. To form a proper estimate of the advantages derived from this source, perhaps the readiest way is to suppose, that there was no such faculty as that of hearing. We pity a deaf

person, on account of the privations to which he is subject; yet he possesses many advantages, from living among those who are endowed with the gift of which he is deprived. Let it be imagined, that the faculty of hearing had been entirely denied to the animal creation; and how many sources of enjoyment and of improvement would have been withheld! The want of so useful a medium of communication, would throw an effectual barrier in the way of advancement in the arts and comforts of social life; would shut us out from all the enjoyments of melody, and from those thousand nameless sympathies communicated by the intonations of the human voice. A dumb world would be a world of barbarism. The rational powers would remain unexpanded, the stimulus to exertion would be wanting, and man would be reduced to a level with the brutes.

Now, it is on the wonderful adaptation between the ear and the external air, that the perception of sound depends, and especially that exquisite perception of the minute distinction of sounds, which constitutes the power of receiving communications by means of language. The delicacy of this adjustment will be seen by reflecting on the difference which would be produced by only a slight variation, either in the auditory organ or in the air. Some particular states of the atmosphere are better adapted for the transmission of sounds than others; and it is easy to suppose, that the relations of this element with the ear, might be so altered as to render the vibrations either too loud or too low for utility. If, for example, a man attempt to speak after inhaling hydrogen gas, his voice will scarcely be audible.

Again, the ear is not merely adapted to the intensity of the aerial vibrations which constitute sound, but to various other modifications. The power of perceiving the pitch of voice, or the difference between acute and grave, the quality of sound, or that which distinguishes one voice or sound from another, as well as that which is most important of all, the power of perceiving articulate sounds, all depend on the adjustment to which we have alluded. The familiar circumstance of one person pos

[ocr errors]

sessing a musical ear, of which another is altogether destitute, may serve to illustrate these remarks.

In addition to all this, we have the organs of animals, fitted for uttering each its own appropriate sounds; by virtue of which the lion roars, the horse neighs, the cow lows, the sheep bleats, and the dog barks; and, above all, man is gifted with those wonders of voice, by which he is enabled to form for himself the complicated structure of language, and thus to give full expression to his inward sentiments and feelings.

Most assuredly, whoever contemplates these finely and skilfully adjusted relations, with candor, cannot fail to recognise an intelligent Designer. When we are asked how it comes that the eye should be formed for light, and light for the eye; or how it happens that the ear and the organ of speech should be so conformed to each other, and to the surrounding fluid of air, and this fluid to them, that from these combinations such incalculable blessings should flow to living creatures, and especially to man, it seems altogether vain to attempt any other reply, than that this is the work of an all-wise and benevolent Creator. Let any man examine these questions, with what minuteness he pleases, and attempt, by whatever ingenuity he may legitimately exercise, to escape from this conclusion, and he will only be more powerfully compelled to acknowledge the hand of a wonder-working and paternal God.

The instance of the eye is particularly striking, because it is so remarkably artificial, or rather because it can be so directly compared with works of human art. It is, as we have said, a complete and most skilfully constructed optical instrument, and its comparison with the camera obscura, or the telescope, brings out so many points of resemblance, that it seems impossible to attribute contrivance to the one, and deny it to the other. But there is another sentiment, which such a comparison forcibly impresses on the mind. There are points of contrast, as well as of resemblance, and in all these the unspeakable superiority of the Divine Artificer is most conspicuous. The human instrument is but a feeble and

imperfect imitation of that which has come from the hands of the Creator. In the latter, there are many things which art in vain attempts to imitate, the mechanical skill is so exquisite, and the adaptations so nice. And then, with what waste of thought, with what laborious stretch of ingenuity, with what patient toil and pains is the human instrument constructed. Who will venture to compare with this the creative power of the Omnipotent?

SECOND WEEK-TUESDAY.

GROWTH OF VEGETABLES.

I HAVE, in a former volume, given an account of the first developement of vegetable productions, and detailed the general principles of their organization, and of their vital powers.* What remains, as introductory to a sketch of the properties of individual plants, which arrive at maturity during the summer months, is to explain their mode of growth, and the various contrivances by which they are adapted to the climate and localities in which they are found.

The first thing worthy of observation on this subject, is, that two different modes have been adopted in the growth of vascular plants, with obvious reference to the state of external nature in the latitudes where they are respectively placed; the one of which is named exogenous, [growing from without] the other, endogenous, [growing from within.] In the former, the successive additions to the substance of the stem, are made on the exterior side of the parts from which they proceed; in the latter, this process is reversed, and the growth is the result of additions made internally. All the trees of the regions north of the tropics, belong to the exogenous or

* Spring,' 'Articles Vegetation, Developement of Seeds and Plants, Vital Powers of Plants, &c.

III.

5

IX.

« PreviousContinue »