In its motion towards the west, the Pacific is impeded by an immense archipelago of flats, islands, submarine mountains, and even land of considerable extent; it penetrates into this labyrinth, and there forms one current after another. The direction which the principal of these currents observe, is conformable to the general motion towards the west. But, as might be expected, the inequalities of the basin of the sea, the coasts, and the chains of submarine mountains, sometimes turn these currents toward the north or south. We may easily conceive that a strong repercussion of the waters of the ocean, in consequence of their meeting with a large mass of land, (as New South Wales,) may even produce a counter current, which will return towards the east, and which, by breaking, will also produce other currents, adverse and dangerous to navigators, and such as were encountered by Cook and La Perouse. The Pacific Ocean is bounded on the east by Asia. Beering’s Straits connects it with the Arctic Ocean, and the line which indicates the one hundred and forty-seventh eastern meridian, arbitrarily separates it from the Indian Ocean. Geographers divide the Pacific into the northern and southern, the equator being the line of demarcation. This ocean occupies fifty millions of square miles; nearly one fourth part of the surface of the globe. It covers three times the extent of the Indian, and twice the extent of the Atlantic Ocean. GENERAL REMARKS ON OCEANS. The bed of the ocean is diversified by the same inequalities that are exhibited on the surface of the land. Its greatest depth that has been ascertained by experiment, is seven thousand two hundred feet. Its mean depth is a little over three thousand feet, about the same as the mean heights of the continents and islands above its surface. Parts of the sea differ in saltness, but the difference is slight. Though more bitter than that at a considerable depth, it has been ascertained that the water of the surface is less salt. Inland seas are less salt than the main ocean, on account of the large volumes of fresh water emptied into them. The coldness of the polar seas occasions a more rapid deposit of the saline substances, and renders them more salt than those of the equator. Various theories have been formed to account for the saltness of the sea; one attributes it to the existence of primitive beds of salt at its bottom, another to the corruption of vegetable and animal matter carried into it by rivers. A third theory considers the ocean as the residue of a primitive fluid, which, after depositing all the substances of which the earth is composed, retained the saline principle. Sea-water is freed from its salt only by distillation.