There is, indeed, heat in the body of the globe itself; to say nothing of volcanoes, we may state, that the deeper we penetrate into the earth, the higher does its temperature become--a circumstance which has led many philosophers to infer, that the centre of our globe is in a state of incandescence. It is not here that we ought to moot this theory, neither shall we enter into any speculations relative to the intrinsic nature of heat; like light, it is a mysterious agent or product, imponderable, yet subject to certain laws--laws which belong to a branch of philosophy into which it is not now our province to enter. It may, however, be permitted us to state a few simple facts relative to the atmospheric temperature of our globe, and the adaptation of organic beings to the different degrees of heat within the inter-tropics, in the temperate and in the polar latitudes. Climate varies not only according to latitude, but also according to elevation, the relative proportions of land and water, the nature of the surface of the land, the extent of forests, etc. An island, for example, like England, surrounded by the sea, destitute of mountains of vast elevation, or of extensive morasses or forests, though lower in atmospheric temperature during the summer months than the parallel portions of the continent, has a milder atmospheric temperature during winter. The cold of North America during winter is greater than in the same parallels of latitude in the old world. Canada, for example, lies parallel to the northern half of Spain and France, (between 40° and 50° N. lat.) The severity of a Canadian winter is well known. At Quebec, the summer is that of Paris, the winter that of St. Petersburg. At New York, the summer is that of Rome, the winter that of Copenhagen. The same observations apply to the eastern portions of Asia. At Pekin, the scorching heat of summer is greater than at Cairo, while the winters are as rigorous as at Upsal. To the different climates of the globe certain plants and animals are especially adapted; organic existence ranges from the poles to the equator. How varied, how multitudinous, how wonderful, are the forms and structures of organic creation, from the moss or lichen, which creeps upon the surface of the rock, to the towering palm or gigantic oak--from the microscopic animalcule or puny insect, to the ponderous elephant or enormous whale! But, as we have said, every distinct region has, in a general sense, its own _flora_ and its own _fauna_. It is in tropical countries, beneath a fervid sun, that vegetation presents us with its utmost magnificence. There we see forests of evergreen trees, palms, and arborescent ferns--there bloom flowers of gorgeous hue, and luscious scent--there ripen fruits of most exquisite flavour, attractive both to the sight and the taste.