At the end of the Tertiary period the earth was much in the same state that it is at present with regard to the distribution of land and water. The preponderance of land in the northern hemisphere indicates a prodigious accumulation of internal energy under these latitudes at a very remote geological period. The forces that raised the two great continents above the deep, when viewed on a wide scale, must evidently have acted at right angles to one another, nearly parallel to the equator in the old continent, and in the direction of the meridian in the new; yet the structure of the opposite coasts of the Atlantic points at some connexion between the two.

The tendency of the land to assume a peninsular form is very remarkable ; and it is still more so that almost all the peninsulas tend to the south, while to the north, with a very few exceptions, the two great continents terminate in a very broken line, and. as they sink under the Icy Ocean, the tops of their high lands and mountains rise above the waves and stud the coast with innumerable snow-clad rocks and islands. Eastern Asia is evidently continued in a subaqueous continent from the Indian Ocean across the Pacific nearly to the west coast of America, of which New Holland, the Indian Archipelago, the islands of the Asiatic coast and of Oceania, are the great table-lands and summits of its mountain-chains.

North America is divided into four distinct water systems by the Rocky Mountains, the Alleghannies, and a table-land which contains the great lakes, and separates the rivers that flow into the Arctic Ocean from those that go to the Gulf of Mexico. This table-land is a level, nowhere more than 1200 or 1500 feet above the surface of the sea, and is itself drained by the St. Lawrence and the rivers that flow into Hudson's Bay. The St. Lawrence rises in Lake Superior, and, after joining the five great lakes, runs north-east into the Atlantic, and ends in a wide estuary. It has a basin of 537,000 square miles, of which 149,000 are covered with water, exclusive of the many lesser lakes with which it is in communication.

North of the watershed there is an endless and intricate labyrinth of lakes and rivers, almost all connected with one another. But the principal streams of these arctic lands are the Great Fish River, which flows north-east in a continued series of dangerous and all-but impassable rapids to the Arctic Ocean at Melville Strait. The Copper-mine River, of much the same character, after traversing many lakes, enters the Icy Sea at George IV.'s Gulf; and the M'Kenzie, a stream of greater magnitude, formed by the confluence of the Peace River and the Athabasca from the Rocky Mountains, after flowing north over 16 degrees of latitude, enters the frozen ocean in the Esquimaux country somewhere beyond the arctic circle.

Three hundred thousand insects are known: some with wings, others without; some are aquatic, others are aquatic only in the first stage of their existence; and many are parasitical. Some land insects are carnivorous, others feed on vegetables; some of the carnivorous tribe live on dead, others on living animals, but they are not half so numerous as those that live on vegetables. Some change as they are developed; in their first stage they eat animal food, and vegetables when they come to maturity. Insects increase in kinds and in numbers from the poles to the equator: in a residence of eleven months in Melville Island, Sir Edward Parry found only six species, because lichens and mosses do not afford nourishment for the insect tribes, though it is probable that every other kind of plant gives food and shelter to more than one species; it is even said that 40 different insects are quartered upon the common nettle.

The increase of insects from the poles to the equator does not take place at the same rate everywhere. The polar regions and New Holland have very few specifically and individually; they are more abundant in North Africa, Chili, and the sandy deserts west from Brazil; North America has fewer species than Europe in the same latitude, and Asia has few varieties of species in proportion to its size; Europe, especially Germany, produces many more species than intertropical Africa; Caffraria, the African and Indian islands, are nearly the same as to species; but by far the richest of all, both in species and numbers, are central and intertropical America.

The oriental plateau, or table-land of Tibet, is an irregular four-sided mass stretching from S.W. to N.E., enclosed and traversed by the highest mountains in the world. It is separated from the tableland of Persia by the Hindoo Coosh, a branch of the Himalaya, which occupies the terrestrial isthmus between the low lands of Hindostan and Bucharia.

The cold dreary plateau of Tibet is separated on the south from the glowing luxuriant plains of Hindostan by the Himalaya, which extends 2800 miles from the western extremity of the Hindoo Coosh in Cabulistan to the Gulf of Tonkin in China. The chain of the Altaï,to the north, 4500 miles long, divides the table-land from the deserts of Asiatic Siberia, and, stretching to the sea at Okhotzk under various names, it bends to the N.N.E., and terminates at Behring's Straits, the utmost extremity of Asia. The table-land terminates in the east, partly in the long Chinese chain of the Khing-Khan and Inshan Mountains, which stretch from the Altaï range to the great bend in the Yellow River in China, and farther south by the nameless and almost unknown magnificent mountains in the western provinces of the Chinese empire. On the west the table-land has its limits in the Beloot Tagh, or Cloudy Mountains, the Tartash Tagh of the natives, a transverse range, which leaves the Hindoo Coosh nearly at a right angle about the 72nd degree of E.

Before Sir James Ross's voyage to the Antarctic regions, the profound and dark abysses of the ocean were supposed to be entirely destitute of animal life; now it may be presumed that no part of it is uninhabited, since during that expedition live creatures were fished up from a depth of 6000 feet. But as most of the larger fish usually frequent shallow water near the coasts, deep seas must form barriers as impassable to the greater number of them as mountains do to land animals. The polar, the equatorial ocean, and the inland seas, have each their own particular inhabitants; almost all the species and many of the genera of the marine creation are different in the two hemispheres, and even in each particular sea; and under similar circumstances the species are for the most part representative, not the same. Identity of species, however, does occur, even at the two extremities of the globe, for living animals were brought up from the profound depths of the Antarctic Ocean which Sir James Ross recognised to be the very same species which he had often met with in the Arctic seas. “The only way they could have got from the one pole to the other must have been through the tropics; but the temperature of the sea in these regions is such that they could not exist in it unless at a depth of nearly 2000 fathoms. At that depth they might pass from the Arctic to the Antarctic Ocean without a variation of 5 degrees of temperature; whilst any land animal, at the most favourable season, must experience a difference of 50 degrees, and if inwinter, no less than 150 degrees of Fahrenheit's thermometer;”—a strong presumption that marine creatures can exist at the depth and under the enormous pressure of 12,000 feet of water.

The great northern plain is broken by two masses of high land, in every respect inferior to those described: they are the Scandinavian system and the Ural Mountains, the arbitrary limit between Europe and Asia.

The range of primary mountains which has given its form to the Scandinavian peninsula begins at Cape Lindesnaes, the most southerly point of Norway, and, after running along its western coast 1000 miles in a north-easterly direction, ends at Cape Nord Kyn on the Polar Ocean, the extremity of Europe. The highest elevation of this chain is not more than 8412 feet. It has been compared to a great wave or billow, rising gradually from the east, which, after having formed a crest, falls perpendicularly into the sea in the west. There are 3696 square miles of this peninsula above the line of perpetual snow.

The southern portion of the chain consists of ridges following the general direction of the range, 150 miles broad. At the distance of 360 miles from Cape Lindesnaes the mountains form a single elevated mass, terminated by a table-land, which maintains an altitude of 4500 feet for 100 miles. It slopes towards the east, but plunges at once in high precipices into a deep sea on the west.

The surface is barren, marshy, and bristled with peaks; besides, an area of 600 square leagues is occupied by the Snae Braen, the greatest mass of perpetual snow and glaciers on the continent of Europe.

From similarity of physical circumstances the arctic flora of America bears a strong resemblance to that of the northern regions of Europe and Asia. This botanical district comprises Greenland, and extends considerably to the south of the arctic circle, especially at the eastern and western ends of the continent, where it reaches the 60th parallel of N. lat., and even more; it is continued along the tops of the Rocky Mountains almost to Mexico, and it re-appears on the White Mountains and a few other parts of the Alleganies.

Greenland has a much more arctic flora than Iceland; the valleys are entirely covered with mosses and marsh plants, and the gloomy rocks are cased in sombre lichens that grow under the snow, and the grasses on the pasture grounds that line the fiords are nearly four times less varied than those of Iceland. In some sheltered spots the service-tree bears fruit, and birches grow to the height of a few feet; but ligneous plants in general trail on the ground.

The arctic flora of America has much the same character with those of Europe and Asia, and many species are common to all; still more are representative, but there is a difference in the vegetation at the two extremities of the continent; there are 30 species in the east and 20 in the west end which grow nowhere else.

The change produced in the civilized world within a few years, by the application of the powers of nature to locomotion, is so astonishing, that it leads to a consideration of the influence of man on the material world, his relation with regard to animate and inanimate beings, and the causes which have had the greatest effect on the physical, moral, and intellectual condition of the human race.

The former state of our terrestrial habitation, the successive convulsions which have ultimately led to its present geographical arrangement, and to the actual distribution of land and water, so powerfully influential on the destinies of mankind, are circumstances of primary importance.

The position of the earth with regard to the sun, its connexion with the bodies of the solar system, together with its size and form, have been noticed by the author elsewhere. It was there shown that our globe forms but an atom in the immensity of space, utterly invisible from the nearest fixed star, and scarcely a telescopic object to the remote planets of our own system. The increase of temperature with the depth below the surface of the earth, and the tremendous desolation hurled over wide regions by numerous fire-breathing mountains, show that man is removed but a few miles from immense lakes or seas of liquid fire. of temperature.

The vapour which rises invisibly from the land and water ascends in the atmosphere till it is condensed by the cold into clouds, which restore it again to the earth in the form of rain, hail, and snow: hence there is probably not a drop of water on the globe that has not been borne on the wings of the wind. Part of this moisture restored to the earth is reabsorbed by the air, part supplies the wants of animal and vegetable life, a portion is carried off bystreams, and the remaining part percolates through porous soils till it arrives at a stratum impervious to water, where it accumulates in subterranean lakes often of great extent. The mountains receive the greatest portion of the aerial moisture, and, from the many alternations of permeable and impermeable strata they contain, a complete system of reservoirs is formed in them, which, continually overflowing, form perennial springs at different elevations, that unite and run down their sides in incipient rivers. A great portion of the water at these high levels penetrates the earth till it comes to an impermeable stratum below the plains, where it collects in a sheet, and is forced by hydrostatic pressure to rise in springs through cracks in the ground to the surface. In this manner the water which falls on hills and mountains is carried through highly inclined strata to great depths, and even below the bed of the ocean, in many parts of which there are springs of fresh water.