XIV. BOOK pede it, carries along with it the polar ice even to latitudes where the motion of the tropical current begins to be felt. This is the reason why, in the southern hemisphere, floating pieces of ice are met with at 50, and even at 40 degrees. Current of the Strait of Bass. Current of The Pacific Ocean, in its motion towards the west, is impeded by an immense archipelago of flats, islands, submarine mountains, and even lands 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 towards 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 differently directed. Here then is the origin of these currents, so adverse and dangerous, which Cook and La Perouse mention in their voyages. The principal current, setting towards the west, still acts with force in the recently discovered strait, which separates New Holland from Van Diemen's Land; this is the current which bore away Captain Flinders, and which hindered so many ancient navigators from entering into that strait, because they approached it in a direction contrary to that of the sea. The same current flows through the channel which separates New Holland from New Guinea; but here, from the innumerable inequalities which it meets with, it is subdivided into several currents, of varied and inconstant direction. Let us now enter upon the consideration of the Indian the Gulf of Seas. There we shall find the celebrated perpetual curBengal. rent, which runs along from New Holland, and from the * Flinders, Observations during his Voyage to the Strait of Bass. London, 1811. Compare the Voyage of Entrecasteaux, i. 230. XIV. Island of Sumatra, always to the north, as far as the bot- BOOK tom of the Gulf of Bengal. This current arises from the pressure of the polar currents upon the large opening which the Indian Sea presents to the south. That sea is bordered towards the north by a continent; the equatorial current, which is formed there, is therefore only feeble, or altogether ceases, as there is no mass of cold water passing from the north. On the other side, the Pacific Ocean cannot carry its impetus thither; it is broken and dispersed in the labyrinth of islands. Thus the influence of the southern polar streams predominates without a rival, and without an obstacle in the Indian Sea; and these produce that perpetual current which sets towards the Gulf of Bengal, upon a line more and more inclined towards the north west, or following the conformation of the coasts.* currents of The action of the general motion of the ocean, at first weak in the Indian Sea, as we have already mentioned, augments by degrees, till it gains the ascendancy. It is easy to conceive that a general impulse which acts in a vast fluid, and which influences all its particles, ought to increase according as that fluid extends in the direction of the moving power. One part of the sea then reacts upon Different the other, and the sum of these repeated effects becomes in the Indian time immense. These principles show why, towards the Seas. Island of Java, the natural motion of the sea is changed by the northern current,† of which we have already spoken, and why this same motion towards the west is found in the neighbourhood of Ceylon, and the Maldivia Islands. But a new local circumstance again makes this motion decline from its natural direction. A chain of islands and sballows extends from Cape Comorin, in the peninsula of India, to the northern point of Madagascar. The principal current being interrupted by these obstacles, turns to Varenius, Géog. Générale, ch. xiv. prop. 24. Voyages de Gentil, de Macartney, and de Marchand, &c. + We say a Northern Current, or a Southern Current, to designate a current with such a direction. BOOK wards the south-west; and, in maintaining that direction, XIV. glides along that chain of mountains, some of them submarine, others on the shore. Having passed Madagascar, Current of coast. against that continent, and coasts of Natal, (Terre Nawhere the coast of Africa, it turns towards Africa, dashes We have said, that towards the Maldivia Islands, the the Natal principal current, or great mass of water, turns to the southwest; but the more superficial currents, and consequently the most variable, continue their course from the east to the west, that is, towards the Gulf of Arabia, and the coasts of Zanguebar. These are the currents which, setting towards the south-west, render the Mozambique Channel so difficult to navigate, and which have given the name it bears to Cape Corrientes, upon the coast of Inhambane. They reunite at the bottom of this Cape with the perpotual current. Currents eastern coast of Let us remark here, that in general the currents which do not extend to a great depth under the level of the waters, are liable to change with the winds, particularly when they blow for a long time with an equal and constant force, as the Monsoons do. These are the winds which give by turns entirely opposite directions to the currents which prevail from the Maldivia Islands to Arabia and Zanguebar. The shallows and rocks with which these parts are strewed, equally contribute to produce the same effect. The northern current which runs along Nova Zemupon the bla, and the Island of Sumatra, impels one of its branches through the strait of Sunda. This current, according to some authors, is the same that predominates in the Chinese Seas, and which La Perouse found to be of such strength Asia. * Varenius, Géographie Générale, ch. xiv. prop. 25. XIV. in the sea of Japan, and in the channel of Tartary.* But BOOK after comparing together the accounts of different navigators, it appears to us that these currents not only vary with the Monsoons, but that no connection subsists between them. All the southern and northern currents that we observe along the eastern coasts of the continents, are only necessary continuations of the general motion of the ocean towards the west; the waters, impelled by this motion towards the eastern coasts of the two continents, and finding no outlet, must with much force, flow back along the coasts in a southern or northern direction, as local circumstances determine them. In Behring's Straits, the polar current, which brings the ice from the polar seas to the environs of Kamtchatka, is distinctly felt. the West ern Ocean. Let us go on to the currents of the Western Ocean. The Currents of form of the basin, whose length is much greater than its breadth, is what in a great measure determines these currents. The first current which presents itself to our notice, is that which carries forward the waters from the Ethiopian Ocean, along the coasts of Brazil, and through the Strait of Magellan, into the Pacific Ocean. This course is conformable to the general progress of the ocean. It would appear from the voyages of Marchand and Ingraham, that between Terra del Fuego, the new Georgia of the south, and the Sandwich Islands, (or the Thule Australis of Cook,) there are several opposite currents, but our knowledge of them is far from being accurate. Augustin. The most celebrated perpetual current of the Atlantic Current of Cape St. Ocean is that which commences on this side of Cape St. Augustin, in Brazil, and extends towards the eastern coasts of America. It is extremely rapid, and is felt in all the extent of sea over which the Antilles are scattered. This current is only the result of the general motion of the Atlantic Sea towards the west; it prevails between the Voyage de La Pérouse. See after, the articles of Japan, of Corea, of the Jand Yeso, &c. XIV. BOOK 30th degree of northern, and the 10th of southern latitude, and begins at 20 or 30 leagues from the coasts of Africa. This is the reason why European vessels, in order to profit by this current, and the trade winds, proceed to the Canary Islands before they attempt to traverse the ocean. Current of the gulf of Guinea. Mexico. Upon the coasts of Africa, within the limits pointed out above, there exists a current directly contrary to the preceding; which is neither less rapid nor less steady. Ships, if they approach too near these coasts, are drawn into the Gulf of Guinea, and with great difficulty get out of it. No adequate cause can be assigned for this singular current. Some authors imagine, that there are two currents in the Atlantic ocean, one at the surface, the other at the bottom; and that it is this latter which brings the waters towards Africa; but such an explanation is inadmissible, from the well known fact of the general motion of the sea, which is not superficial, but which pervades the whole of the mass. It is more probable that the current in question comes from the Straits of Gibraltar, along the coasts of Africa only, where the waters have not acquired all the velocity of the general motion; but we can affirm nothing with certainty on the subject. Current of A third very celebrated current is that by which the wathe Gulf of ters of the Atlantic are carried violently into the Gulf of Mexico, and, discharging themselves through the channel of Bahama, run with inconceivable rapidity towards the north, or rather the north-east. It follows the coasts of the United States, becomes larger, and at the same time weaker, and extends, according to some navigators, as far as the coasts of Scotland and Norway. It is easily known by the beautiful blue colour of its waters. Currents of Sea. The polar currents of the north exhibit very remarkable the Frozen effects; it is they which bring upon the coasts of Iceland such an enormous quantity of ice, that all the northern gulfs of that country are filled with it to the very bottom, though they are often 500 feet in depth. The ice is sometimes raised up so as to form mountains. Some years no |