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

Obferve then, in this ftructure, that which we call relation. There is no natural connection between a small sunk eye and a shovel palmated foot. Palmated feet might have been joined with goggle eyes; or small eyes 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 set out from a different part. In the inftance before us, we may either confider the shape 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 ftructure of the eye, as the only one which would have fuited with the action to which

the

the feet are adapted. The relation is manifeft, whichever of the parts related we place firft 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 species of relation. It is relation, when the defects of one part, or of one organ, are fupplied by the structure of another part, or of another organ. Thus,

I. The fhort, unbending neck of the ele phant, 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 so heavy could not have been fupported at the end of a longer lever. To a form therefore, in fome respects neceffary, but in fome refpects also inadequate to the occafions of the animal, a fupplement is added, which exactly makes up the deficiency under which he laboured.

If

If it be fuggefted, that this probofcis may have been produced in a long course of generations, by the conftant endeavour of the elephant to thrust out his nofe, (which is the general hypothesis by which it has lately been attempted to account for the forms of animated nature,) I would ask, how was the animal to subsist in the mean time; during the procefs; until this prolongation of fnout were completed? What was to become of the individual, whilft the fpecies was perfecting?

Our business at prefent is, fimply to point out the relation, which this organ bears to the peculiar figure of the animal, to which it belongs. And, herein, all things correfpond. The neceffity of the elephant's probofcis arifes from the fhortnefs of his neck; the shortnefs of the neck is rendered neceffary by the weight of the head. Were we to enter into an examination of the structure and anatomy of the probofcis itself, we should see in it one of the moft curious of all examples of animal mechanism. The difpofition of the ringlets and fibres, for the purpose, first, of forming a long cartilaginous pipe; fecondly, of contracting and lengthening that pipe; thirdly, of turning it in every direction at the will of the

animal;

animal; with the fuperaddition, at the end, of a fleshy production, of about the length and thickness of a finger, and performing the office of a finger, fo as to pick up a straw from the ground; these properties of the fame organ, taken together, exhibit a fpecimen, not only of defign, (which is attefted by the advantage,) but of confummate art, and, as I may say, of elaborate preparation, in accomplishing that defign.

II. The hook in the wing of a bat, is ftrictly a mechanical, and, alfo, a compenfating contrivance. At the angle of its wing there is a bent claw, exactly in the form of a hook, by which the bat attaches itself to the fides of rocks, caves, and buildings, laying hold of crevices, joinings, chinks, and roughneffes. It hooks itself by this claw; remains fufpended by this hold; takes its flight from this pofition: which operations compensate for the decrepitude of its legs and feet. Without her hook, the bat would be the most helpless of all animals. She can neither run upon her feet, nor raise herself from the ground. These inabilities are made up to her by the contrivance in her wing: and in placing a claw on that part, the Creator has deviated from the analogy