the yellow, next orange; and lastly the red, which is the least refrangible of all.

The nature of coloured bodies contributes much to the diversity of their colours. The smallest particles of most bodies are transparent; hence they break, absorb, or reflect, the rays of light, sometimes one way, and sometimes another, like prisms. And what completely proves that colours are not inherent in bodies, is, that the neck and plumage of a pigeon or peacock; and stuffs, such as taffeta and other silk stuffs, &c.; change colour according to the position in which they are placed. This may enable us to understand whence the variety of colours proceeds; which is nothing more than that the surface of bodies is composed of extremely thin laminæ, which, according to their thickness, reflect certain coloured rays, whilst they admit or absorb others in their pores. Thus, when a body whose surface is smooth, reflects and throws back almost all the rays of light, it appears white; but when it absorbs them all, it is black.

Let us here admire the goodness and wisdom of God: for if the rays were not divisible and differently coloured, all would be uniform, and we could only distinguish objects by reasoning, and by the circumstances of time and place. We should be reduced to the most awkward perplexity and uncertainty; our eyes would be fatigued with constantly seeing one colour, and we should be weary of the continued uniformity. But the diversity of colours existing in nature diffuses beauty over the earth, and procures new and repeated variety of pleasure. In this we have abundant proofs of the provident cares of God; who has provided for our pleasures as well as our necessities, and in creating the world has regarded the beauty as much as the perfection and utility of his works. Far as the eye can reach, we discover new and varied beauties in the plains, in the valleys, and the mountains; every thing conduces to our pleasure, and calls forth our gratitude.

AUGUST XII.

Habitations of the Beavers.

Ir a man who had never heard of the industry of beavers, and their manner of building their dwellings, were shewn the edifices they construct, he would suppose them to be the work of some most skilful architects. Every thing is wonderful in the labours of these amphibious animals; the regular plan, the size, the solidity, and the admirable art, of their buildings, must fill every attentive observer with astonishment. The beavers choose their place of abode where there is a plentiful supply of provisions, and a river in which they may form a lake to bathe in. They begin by constructing a dyke or bank, which keeps the water level with the floor of their building: this bank is sometimes a prodigious work, from ten to twelve feet thick at the foundation: it is made sloping, and gradually diminishes in thickness, till, towards the top, it is not more than two feet broad. The materials of which it is composed are wood and clay. The beavers cut pieces of wood as thick as a man's arm with great facility. They fix these in the earth by one of their extremities, very near to each other, and entwine round them other pieces that are smaller and more flexible. But as the water may still pass through, and leave their watering-place dry, they make use of clay to fill up all the interstices both within and without, so well, that the water cannot possibly flow through, and in proportion as the water rises, they raise their beck.

Having finished their dyke, they begin to work at their houses; which are round or oval buildings divided into three stories, raised one above the other, one of which is below the dyke and generally filled with water, the other two are above. They fix these buildings very firmly upon the brink of their lake, and always with stories, that if the water should rise, they may still be able to lodge above it. If they find a little island near their watering-place, they build their house upon it, as being more firm; and they are also less incommoded by the water, in which they cannot remain long at a

time. If this convenience is not to be obtained, with the assistance of their teeth they force stakes into the earth to support their building against the force of wind and water. They make two openings at the bottom to go out into the water; one leads to the place where they bathe, the other to the place where they deposit whatever might dirty their upper apartments. They have a third door, placed higher up, for fear of being taken when the ice closes up the lower doors. Sometimes they build their houses entirely upon dry ground, and dig ditches from five to six feet deep, down to the water. They use the same materials and the same industry for their buildings as for their banks. The walls are perpendicular, and about two feet thick. With their teeth they cut off the ends of the wood and sticks that project from the wall; and then mixing clay with dry grass, they make a composition, with which they plaster, by means of their tail, the inside and the outside of their building. The inside of their house is arched, and its size is proportioned to the number of inhabitants. A space twelve feet long, by eight or ten broad, is sufficient for eight or ten beavers. If the number is greater, they enlarge their building in proportion.

The instruments which the beavers use are four strong and sharp teeth the two fore-feet, of which the toes are separated; the two hind feet, which are furnished with membranes; and their tail, which is covered with scales, and is like an oblong trowel. With only these simple tools, they excel our masons and carpenters with all their apparatus of trowels, squares, axes, saws, &c. With their teeth they cut the wood which they use in their buildings; their fore-feet serve them to dig the ground, and to prepare the clay. They use their tail both to carry the mortar or clay and to plaster their houses.

The works of beavers then have the greatest resemblance to those of men; and upon their first appearance we may imagine them to be produced by rational and thinking beings. But when we examine them nearer, we shall find that in all their proceedings these animals do not act upon the princi

ples of reason, but by an instinct which is implanted in them by nature. If reason directed their labours, we should naturally conclude that the buildings which they now construct would be very different from those they formerly made, and that they would gradually advance towards perfection. But we find that they never vary in the least from the rules of their forefathers, never deviate from the circle prescribed to them by nature; and the beavers of the present time build exactly after the same plan as those which lived before the deluge. But they are not the less worthy of our admiration. In these sagacious creatures we have an example of the great diversity there is in the instinct of animals. How superior is the instinct of the beaver to that of the sheep! May we profit by our discoveries of the different faculties of animals, so as more and more to advance in perfection, and increase our knowledge of the love and infinite power of God!

AUGUST XIII.

Manner in which the Nutrition of the Human Body is effected. ALIMENTARY matter, when taken into the stomach, is separated into two parts: the one nutritious, which remains in the body; the other not nutritive, is expelled from it. It is first requisite that the food should be broken, and its parts decomposed. This is begun in the mouth by the process of mastication. The fore-teeth, or incisors, cut and divide the pieces; the canins, or side-teeth, tear them; and the double teeth grind them small. The tongue and lips also contribute to this, by keeping the food under the teeth as long as is necessary. Certain glands, pressed upon during the process of mastication, pour out saliva to moisten the food, and render it more easily divisible, as well as facilitate its digestion. Hence the great advantage of well chewing the food before it is swallowed.

The aliments thus comminuted, moistened, and mixed, are received into the pharynx or beginning of the throat; in which canal there are glands that continually secrete a fluid

that lubricates the throat, and renders the passage of the food more easy. When this is too dry, the sensation of thirst excites us to drink. The food follows the course of the throat till it is received into the stomach; a membranous bag, in which is secreted a fluid called the gastric juice, by the action of which upon the food digestion is performed. When we have too long abstained from eating, the gastric juice, stimulating the nervous coat of the stomach, occasions the sensation of hunger. The stomach is continually in motion by the contraction of its fibres from above downwards, so that its cavity is straightened; the lower termination rises towards the middle, and the whole is equally contracted. The aliment, prevented from returning into the throat by means of a valve covering the upper orifice of the stomach, readily passes through the inferior opening or pylorus into the intestinal canal, which is properly a continuation of the stomach. This canal is subject to a constant motion, called the peristaltic motion, by means of which the whole alimentary mass is completely agitated.

By the preceding operations, the aliment is reduced to a pulpy mass, which passes slowly through the intestines by means of their vermicular motion; and is there mixed with the bile, which is secreted by the liver, and stimulates the intestines to act. In each intestine are discovered the orifices

of very fine vessels, called lacteals. The whitest and purest part of the alimentary mass passes through these, and is conveyed by them into a larger vessel, which passes from the abdomen through the chest, and terminates in the veins. The white colour of the chyle is then lost among the blood, and it is no longer distinguished from that fluid; and thus prepared and perfected, it is conveyed by numerous canals to every part of the body, to which it imparts life and nourishment. The gross and innutritious part which remains in the large intestines, passes from the colon into the rectum, whence in due time it is expelled from the body.

From this short account we learn what a variety of operations are requisite to accomplish one of the daily necessi⚫