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of its underground life. It is a special purpose, fpecially confulted throughout. The form of the feet fixes the character of the animal. They are so many fhovels: they determine its action to that of rooting in the ground; and every thing about its body agrees with this deftination. The cylindrical figure of the mole, as well as the compactness of its form, ariling from the terfenefs of its limbs, proportionally leffens its labour; becaufe, according to its bulk, it thereby requires the leaft poffible quantity of earth to be removed for its progrefs. It has nearly the fame ftructure of the face and jaws as a fwine, and the fame office for them. The nofe is fharp, flender, tendinous, ftrong; with a pair of nerves going down to the end of it. The plush covering, which, by the smoothness, clofenefs, and polish of the short piles that compofe it, rejects the adhefion of almoft every fpecies of earth, defends the animal from cold and wet, and from the impediment, which it would experience by the mold fticking to its body. From foils of all kinds the little pioneer comes forth bright and clean. Inhabiting dirt, it is, of all animals, the neatest.

But what I have always moft admired in

the mole is its eyes. This animal occafionally visiting the surface, and wanting, for its fafety and direction, to be informed when it does fo, or when it approaches it, a perception, of light was neceflary. I do not know that the clearness of fight depends at all upon the fize of the organ. What is gained by the largenefs or prominence of the globe of the width in the field of vifion.

eye

is.

Such a capacity would be of no ufe to an animal which was to feek its food in the dark. The mole did not want to look about it; nor would a large advanced eye have been easily defended from the annoyance, to which the life of the animal must constantly expose it. How indeed was the mole, working its way under ground, to guard its eyes at all? In order to meet this difficulty, the eyes are made fcarcely larger than the head of a corking pin; and these minute globules are funk fo deep in the skull, and lie fo fheltered within the velvet of its covering, as that any contraction of what may be called the eyebrows, not only closes up the apertures which lead to the eyes, but prefents a cushion, as it were, to any fharp or protruding fubftance, which might push against

U 4

against them. This aperture even in its ordinary ftate is like a pin hole in a piece of velvet, fcarcely pervious to loofe particles of earth.

eyes

Obferve then, in this ftructure, that which we call relation. There is no natural connection between a fmall funk eye and a shovel palmated foot. Palmated feet might have been joined with goggle eyes; or small might have been joined with feet of any other form. What was it therefore which brought them together in the mole? That which brought together the barrel, the chain, and the fusee, in a watch: defign; and design, in both cafes, inferred, from the relation which the parts bear to one another in the prosecution of a common purpose. As hath already been obferved, there are different ways of ftating the relation, according as we fet out from a different part. In the inftance before us, we may either confider the fhape of the feet, as qualifying the animal for that mode of life and inhabitation, to which the ftructure of its eye confines it; or we may confider the structure of the eye, as the only one which would have fuited with the action to which

the

the feet are adapted. The relation is manifest, whichever of the parts related we place first in the order of our confideration. In a word; the feet of the mole are made for digging; the neck, nose, eyes, ears, and skin, are peculiarly adapted to an underground life; and this is what I call relation,

CHAP.

CHAPTER XVI.

COMPENSATION.

COMPENSATION is a fpecies of relation. It is relation, when the defects of one part, or of one organ, are supplied by the structure of another part, or of another organ. Thus,

I. The short, unbending neck of the clephant, is compensated by the length and flexibility of his probofcis. He could not have reached the ground without it: or, if it be supposed that he might have fed upon the fruit, leaves, or branches of trees, how was he to drink? Should it be asked, Why is the elephant's neck fo fhort? it may be answered that the weight of a head fo heavy could not have been fupported at the end of a longer lever. To a form therefore, in fome respects neceffary, but in some respects also inadequate to the occafions of the animal, a fupplement is added, which exactly makes up the deficiency under which he laboured.

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