The Mississippi is the principal tributary of the Gulf of Mexico, and carries down with it, besides its vast body of waters, a prodigious quantity of organic and unorganic debris. The town of New Orleans, near the mouth of this river, is the principal commercial station along the whole gulf. In the middle of the gulf the winds blow regularly from the northeast; but they vary considerably on approaching the shore. From the Mississippi, along the Florida coast, the south-west wind blows violently in the months of August, September, and October; the north wind prevails during the other nine months. Between the Mississippi and San Bernardo, the wind generally blows in the morning from the south-east or east-southeast, and in the evening from the south-west. Between Catoche and Campeachy the reigning wind, during a great part of the year, blows from the north-east; but from the end of April to September, it comes from the opposite direction. The most remarkable current in the gulf, is that called the Gulf Stream, described in the following chapter.

GENERAL REMARKS ON BAYS.

Many portions of the land and sea extend reciprocally the one into the other. If the sea penetrate into the interior of any continent, it forms there a mediterranean, or inland sea, almost surrounded by land, and having only a narrow opening into the sea. If the extent of such seas be less, and the opening larger, they are called gulfs or bays, two terms which geographical writers have wished to distinguish, but which customary language more frequently confounds. The still smaller portions of sea, surrounded as it were by land, and which afford a shelter for ships, are called ports, creeks, or roads. The first term means a secure asylum; the second is applied to places or ports of much smaller size, and which, when improved or completed by artificial aid, are styled harbors, and roads afford only a temporary anchorage and security from certain winds. The principal bays in the world are Baffin's, Hudson's, James's, Fundy, Massachusetts, Narraganset, Delaware, Chesapeak, Campeachy, Honduras, Bristol, All Saints, Cardigan, Donegal, Galway, Biscay, Bengal, Walwich, Table, False, Angola, Natal, Saldanha, and Botany. The principal gulfs are St. Lawrence, Mexico, Amatique, California, Panama, Guayaquil, St. George, Bothnia, Finland, Riga, Genoa, Naples, Taranto, Venice, Salonica, Persian, Ormus, Siam, Tonquin, Corea, Obi, and Guinea. The principal sounds are Long Island, Albemarle, Pamlico, Prince William's, Queen Charlotte's, and Nootka

CHAPTER XII.-OCEANS.

THE United States are washed by the Atlantic Ocean on nearly the whole of their eastern coast, and by the Pacific on a large portion of their western boundary.

Under the name of the Atlantic, is comprised that mass of water between the eastern coast of America and the western coast of Europe and Africa. In its narrowest part, between Europe and Greenland, it is one thousand miles wide, and opening thence to the south-west with the general range of the bounding continents, spreads under the northern tropic to a breadth of sixty degrees of longitude, or four thousand one hundred and seventy miles, without estimating the Gulf of Mexico. The general phenomena on the two opposing sides of the Atlantic have great resemblance. The Atlan tic coast of the United States presents an elliptic curve in its entire extent, with three intermediate and similar curves; the first extending seven hundred miles from Cape Florida to Cape Hatteras, the second from Cape Hatteras five hundred miles to the outer capes of Massachusetts, and the third formed by the coasts of Massachusetts, New Hampshire and Maine. Opposite to the United States, the Atlantic admits soundings in every place near the shores, always deepening very gradually. We have not found an exact comparison of the natural history of the Atlantic with that of other oceans. The chief phenomenon that marks it along the coast of the states is the Gulf Stream.

Besides the regular periodical currents produced in the ocean by the tides, various others arise from different causes. * The waters of the sea may be put in motion by an external impulse, by a difference in temperature and saltness, by the periodical meeting of the polar ice, or by the inequality of evaporation that takes place in different latitudes. Sometimes several of these causes concur in producing the same effect; at others, their actions are opposed to one another, and their effects wholly or partially destroyed. Some of these currents constantly follow the same direction, others are subject to periodical changes, whilst a third class are more accidental. The most regular and extensive current on the globe is that which constantly flows from east to west, between the tropics, and extends on each side of the equator to about the thirtieth degree of latitude.

This vast current necessarily results from the attraction of the heavenly bodies, the diurnal motion of the earth, and the direction of the trade winds. Its existence is incontestibly proved by the fact, that vessels sailing to the westward, are always ahead of their reckoning; that is, their real situation, as determined by observations of the heavenly bodies, is always found to be west of that estimated from the rate of which the vessel is supposed to sail, as impelled by the wind alone. This difference of situation is occasioned by the general movement of the waters in the same direction, and is, consequently, the proper measure of the current. This is the reason why

*Major Rennel considers the winds the principal cause of currents in the ocean, in which opinion he is supported by several eminent writers; but allowing to the wind great influence, still that influence is not sufficient to account satisfactorily for the various and contradictory facts which are recorded concerning these mighty streams.

navigators, in sailing from Europe to America and the West India Islands, make the latitude of the Canaries, and then shape their course in the direction of the wind and current across the Atlantic.

A general current also flows from the poles towards the equator. This arises from the increased evaporation in the equatorial regions, and the augmented temperature of the waters, which render them specifically lighter than those of the ocean in higher latitudes, as well as from the increased supplies produced by the melting of the polar ice; all of which render these currents necessary to maintain the equilibrium of this perpetually circulating fluid. Their existence and effects are fully attested by the enormous masses of polar ice, which they convey into the more temperate regions of the ocean, and which sometimes float as low as forty degrees of latitude.

These general currents are greatly modified, and changed into various directions by the obstacles they encounter in their progress. The coast of America, and the numerous islands with which it is flanked, intercept the general current of the Atlantic, and create what navigators call the Gulf Stream. This great current enters the Gulf of Mexico, and, sweeping round the shores of that gulf, issues with accelerated velocity towards the north, by the channel between the southern point of Florida and the Bahama Islands. It then rolls along the shore of North America, diminishing in velocity, but increasing in breadth, till it reaches the great bank of Newfoundland. There it suddenly turns towards the east and south-east, and flows with still decreasing velocity, towards the shores of Europe, the Azores, and the coasts of Africa. Navigators readily distinguish this current by the high temperature of its waters, their great saltness, their indigo color, and the shoals of sea-weed† that cover their surface.

Humboldt, in May, 1804, observed its velocity in the twenty-seventh degree of latitude, and found it about eighty miles in twenty-four hours, though the north wind blew very strongly at the time of the observation. When it issues from the Gulf of Florida, its velocity resembles that of a torrent, and is sometimes five miles an hour, but at others not more than three. Between the nearest point of Florida, and the bank of Bahama, the

When the course of this stream is stated to be three thousand geographical miles, some idea may be formed of the force with which it issues through the strait of Florida; a force so great as to be destructive to the land in that quarter. On the north side of Delaware Bay, the encroachments of the sea average nine feet a year, from observations made between 1804 and 1820, and at Sullivan's Island on the north side of the entrance to the harbor of Charleston, South Carolina, the sea carried away a quarter of a mile of land in three years; which destructive power arises from the narrowness of the strait, and the great volume of water that passes through it. As the narrowest part of the strait of Florida is thirty-six nautic miles in breadth, and the annual mean velocity about seventy-three miles per day, a surface of two thousand six hundred and twentyeight square miles of gulf water will be poured into the Atlantic every day, or about two-thirds of a square equatorial degree.

+ Humboldt is of opinion that this weed is produced in large beds, at the bottom of the ocean, and that from these beds it is detached in a ripened state, and collects in large masses on that part of the Atlantic called the Sargasso, or Weedy Sea. Hans Sloane, in his history of Jamaica, quotes many authorities for the weed's being found on the shores of the Cape Verd and Canary islands, as well as among those of the West Indies, and that it is carried to sea, by means of winds and currents. The opinion of Humboldt appears to account more satisfactorily for the accumulation of such vast masses than that of the historian of Jamaica.

breadth is only fifteen leagues, but a few degrees further north, it is seven teen; in the parallel of Charleston it is from forty to fifty leagues in breadth, and in latitude forty degrees and twenty-five minutes, this is increased to nearly eighty leagues. The waters of the torrid zone, being thus forcibly impelled towards the north-east, preserve their high temperature to such a degree, that, in latitude forty and forty-one degrees, it has been found to be seventy-two degrees of Fahrenheit, while out of the current the temperature of the water was only sixty-three degrees.

In the parallel of New York the temperature of the Gulf Stream is equal to that of the sea in latitude eighteen degrees. When the current reaches the western islands of the Azores, where the breadth is about one hundred and sixty leagues, the waters still preserve a part of the impulsion they receive in the Gulf of Florida, nearly one thousand leagues distant. Hence the current proceeds to the Canaries and the coast of Africa, and in the latitude of Cape Blanco, where the waters flow towards the south-west, they mingle with the current of the tropics, and recommence their tour from

east to west.

From this it appears that the waters of the Atlantic, between the eleventh and forty-third degrees, are constantly drawn by currents into a kind of whirlpool; and if a drop of these waters be supposed to return precisely to the place from which it commenced its motion, Humboldt has calcu lated, from the known velocity of the current, that it would require two years and ten months to complete its circuit of three thousand eight hundred leagues.

'A boat,' he observes, which may be supposed to receive no impulsion from the winds, would require thirteen months from the Canary Islands, to reach the coast of Caraccas, ten months to make the tour of the Gulf of Mexico and reach the Tortoise Shoals, opposite the port of Havana, while forty or fifty days might be sufficient to carry it from the straits of Florida to the bank of Newfoundland. Estimating the velocity of the wa ter at seven or eight miles in twenty-four hours, in their progress from this bank to the coast of Africa, it would require ten or eleven months for this last distance. Such are the effects of this slow but regular motion, which agitates the waters of the ocean.' The Gulf Stream furnished to Christopher Columbus indications of the existence of land to the west. This current had carried upon the Azores the bodies of two men of an unknown race, and pieces of bamboo of an enormous size. In latitude forty-five or fifty degrees, near Bonnet Flamand, an arm of the Gulf Stream flows from the south-west to the north-east, towards the coast of Europe. It deposits upon the coasts of Ireland and Norway, trees and fruits belong. ing to the torrid zone. Remains of a vessel burnt at Jamaica were found upon the coast of Scotland. It is likewise this river of the Atlantic which annually throws the fruits of the West Indies upon the shore of Norway. The Pacific is also one of the great boundaries of the United States. By treaties with Spain and Russia our government possesses sovereignty along the Pacific ocean from latitude forty-two degrees to fifty-four degrees and forty minutes, which is equal to about eight hundred and eighty statute miles. This great ocean extends from Beering's Straits to the antarctic circle, a distance of three thousand two hundred leagues, and from Asia and New Holland to America. It is separated from the Atlantic and Antarctic oceans only by imaginary lines. Its extreme breadth, a little north of

the equator, is four thousand five hundred and fifty leagues; between South America and New Holland, latitude thirty degrees south, it is two thousand nine hundred and seventy leagues. It contains an immense number of islands spread over its surface, particularly between latitude thirty degrees north and fifty degrees south, to which modern geographers have given the general appellation of Oceanica. It was first called the South Sea by the European navigators who entered it from the north. Magellan gave it the name of Pacific, on account of the prevalence of calms which he experienced in it; but it by no means deserves the name, as it is remarkable for the fury of its storms, and the agitation of its waters. The trade-winds, which constantly blow between the tropics, render the passage from the western coast of America to Asia very short; but the return is proportionately difficult. The Portuguese were the first Europeans who entered the Pacific, which they did from the east. Balboa, in 1513, discovered it from the summit of the mountains which traverse the Isthmus of Darien. gellan sailed across it from east to west in 1521.*

Ma

The Pacific, by its general motion, retreats from the coast of America, and flows from east to west; and this motion is very powerful in the vast and uninterrupted extent of that sea. Near Cape Corriantes, in Peru, the sea appears to flow from the land by this single cause. Ships are carried with rapidity from the port of Acapulco, in Mexico, to the Philippine Islands. But in order to return, they are obliged to go to the north of the tropics, to seek the polar current, and the variable winds. On the other side, the south polar current, finding no land to impede it, carries along with it the polar ice even to the latitude 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 fifty and even at forty degrees.

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

*Magellan set sail from Europe in September, 1519, with five ships, with the intention by sailing west and south, and following a course never before attempted, to try to make the Molucca Islands at least, by an entirely new passage. Reaching first a southern part of the South American Continent, where he rested for the winter and refreshed his followers, he leisurely proceeded still southerly; and in the October following, first discovered the strait which now bears his name. Neither the dangerous currents of this tempestuous region, however, nor the unknown nautical terrors of the stormy Cape Horn, could damp the ardor of this bold adventurer; and having at length surmounted all the difficulties of the strait, and cleared the wild shores by which they were sur founded, Magellan and his discovery ships first emerged into the great South Sea. Sea-room, almost boundless, the great delight of the sailor, together with steady breezes and salubrious weather, carried these first adventurers on into this new region, with high hopes, and spirits dancing as the waves over which they rode. Finding that the stream of wind which so pleasingly wafted them into a warmer climate, followed the course of the sun and blew steadily in one direction, in that manner which in all similar cases has since been denominated trade-wind; and that, favored by this breeze, the trader and his companions proceeded on with an ease and rapidity beyond their most sanguine expectations, the sea and sky seemed to Magellan equally to be at peace with each other and with the hopeful mariner who had intrusted himself to both; and thinking this unexplored world of waters worthy to be called a Pacific Ocean, he gave it the name, which, however inappropriate, it will probably forever retain.