there is no small difficulty in giving them names, and arranging them properly.

The words appetite, passion, affection, interest, reason, cannot be said to have one definite signification. They are taken sometimes in a larger, and sometimes in a more limited sense. The same principle is sometimes called by one of those names, sometimes by another; and principles of a very different nature are often called by the same name.

To remedy this confusion of names, it might perhaps seem proper to invent new ones. But there are so few entitled to this privilege, that I shall not lay claim to it; but shall endeavour to class the various principles of human action as distinctly as I am able, and to point out their specific differences; giving them such names as may deviate from the common use of the words as little as possible.

There are some principles of action which require no attention, no deliberation, no will. These, for distinction's sake, we shall call mechanical. Another class we may call animal, as they seem common to man with other animals. A third class we may call rational, being proper to man as a rational creature.

CHAP. II.

OF INSTINCT.

THE mechanical principles of action may, I think, be reduced to two species, instincts and habits.

By instinct, I mean a natural blind impulse to certain actions, without having any end in view, without deliberation, and very often without any conception of what we do.

Thus a man breathes while he is alive, by the alternate contraction and relaxation of certain muscles, by which the chest, and of consequence the lungs, are contracted and dilated. There is no reason to think, that an infant new-born, knows that breathing is necessary to life in its new state, that he knows how it must be performed, or even that he has any thought or conception of that operation; yet he breathes as soon as he is born, with perfect regularity, as if he had been taught, and got the habit by long practice.

By the same kind of principle, a new-born child, when its stomach is emptied, and nature has brought milk into the mother's breast, sucks and swallows its food as perfectly as if it knew the principles of that operation, and had got the habit of working according to

them.

Sucking and swallowing are very complex operations. Anatomists describe about thirty pair of muscles that must be employed in every draught. Of those muscles, every one must be served by its proper nerve, and can make no exertion but by some influence communicated by the nerve. The exertion of all those muscles and nerves is not simultaneous. They must succeed each other in a certain order, and their order is no less necessary than the exertion itself.

This regular train of operations is carried on according to the nicest rules of art, by the infant, who has neither art, nor science, nor experience, nor habit.

That the infant feels the uneasy sensation of hunger, I admit; and that it sucks no longer than till this sensation be removed. But who informed it that this uneasy sensation might be removed, or by what means? That it knows nothing of this is evident; for it will as readily suck a finger, or a bit of stick, as the nipple.

By a like principle it is, that infants cry when they are pained or hurt; that they are afraid when left alone, especially in the dark; that they start when in danger of falling; that they are terrified by an angry countenance, or an angry tone of voice, and are soothed and comforted by a placid countenance, and by soft and gentle tones of voice.

In the animals we are best acquainted with, and which we look upon as the more perfect of the brute creation, we see much the same instincts as in the human kind, or very similar ones, suited to the particular state and manner of life of the animal.

Besides these, there are in brute animals instincts peculiar to each tribe, by which they are fitted for defence, for offence, or for providing for themselves, and for their offspring.

It is not more certain, that nature has furnished various animals with various weapons of offence and defence, than that the same nature has taught them how to use them; the bull and the ram to butt, the horse to kick, the dog to bite, the lion to use his paws, the boar his tusks, the serpent his fangs, and the bee and wasp their sting.

The manufactures of animals, if we may call them by that name, present us with a wonderful variety of

instincts, belonging to particular species, whether of the social or of the solitary kind; the nests of birds, so similar in their situation and architecture in the same kind, so various in different kinds; the webs of spiders, and of other spinning animals; the ball of the silk worm; the nests of ants and other mining animals; the combs of wasps, hornets, and bees; the dams and houses of beavers.

The instinct of animals is one of the most delightful and instructive parts of a most pleasant study, that of natural history; and deserves to be more cultivated than it has yet been.

Every manufacturing art among men was invented by some man, improved by others, and brought to perfection by time and experience. Men learn to work in it by long practice, which produces a habit. The arts of men vary in every age, and in every nation, and are found only in those who have been taught them.

The manufactures of animals differ from those of men in many striking particulars.

No animal of the species can claim the invention. No animal ever introduced any new improvement, or any variation from the former practice. Every one of the species has equal skill from the beginning, without teaching, without experience, or habit. Every one has its art by a kind of inspiration. I do not mean that it is inspired with the principles or rules of the art, but with the ability and inclination of working in it to perfection, without any knowledge of its principles, rules, or end.

The more sagacious animals may be taught to do many things which they do not by instinct. What they are taught to do, they do with more or less skill, according to their sagacity and their training. But, in their own arts, they need no teaching nor training, nor is the art ever improved or lost. Bees gather

their honey and their wax, they fabricate their combs and rear their young at this day, neither better nor worse than they did when Virgil so sweetly sung their works.

The work of every animal is indeed like the works of nature, perfect in its kind, and can bear the most critical examination of the mechanic or the mathematician. One example from the animal last mentioned may serve to illustrate this.

Bees, it is well known, construct their combs with small cells on both sides, fit both for holding their store of honey, and for rearing their young. There are only three possible figures of the cells, which can make them all equal and similar, without any useless interstices. These are the equilateral triangle, the square, and the regular hexagon.

It is well known to mathematicians, that there is not a fourth way possible, in which a plane may be cut into little spaces that shall be equal, similar, and regular, without leaving any interstices. Of the three, the hexagon is the most proper, both for conveniency and strength. Bees, as if they knew this, make their eells regular hexagons.

1

As the combs have cells on both sides, the cells may either be exactly opposite, having partition against partition, or the bottom of a cell may rest upon the partitions between the cells on the other side, which will serve as a buttress to strengthen it. The last way is best for strength; accordingly, the bottom of each cell rests against the point where three partitions meet on the other side, which gives it all the strength possible.

The bottom of a cell may either be one plane perpendicular to the side partitions, or it may be composed of several planes, meeting in a solid angle in the middle point. It is only in one of these two ways,