modify its streams, of course; and the great currents in the world of water are, of course, split, deflected, and directed on their way, by all the continents and islands about and around which they flow.

Great currents pour like mighty rivers through the plain of ocean, and fixed by the laws of nature, though their banks be banks of water, they are almost as sharply defined as if they were of granite masonry. These are constant; there are others periodical, occasioned by periodical winds, tides, &c.; and there are also variable currents caused by melting ice, and other accidents, irregular in their oc

currence.

Now let us follow the great stream of cold water flowing from the South Pole, called the Antarctic drift current. From the great barrier of ice and the Antarctic volcano, Mount Erebus, it pours up the Pacific, first in a northnortheasterly direction, then northeast, then more decidedly towards the east, partly, perhaps, deflected into this course by the land of South Victoria; eastward, at any rate, it flows in a salt-water river of enormous breadth, and strikes the Pacific coast of South America, wearing its side into that hollow shape which you may notice on the map. The obstruction of the South American continent splits this great current into two parts, one of which turns southward, washing round Cape Horn; the Cape Horn current, which escapes into the Atlantic Ocean ;-the other, the Peruvian or Humboldt's current, is diverted upwards along the shores of Chili and Peru. Between these two parts, a large body of the southern stream which has not reached the continent is turned back, in about twenty-six degrees latitude, and ninety degrees longitude, to form the southern part of the great equatorial current, into which the mass of water flowing northward up the shores of South America will also be deflected presently.

The current northward, Humboldt's, coasting the continent from Valparaiso to near Guyaquil, has not lost, even under the Equator, all its frost. It turns at Punta Pariña, before reaching Guyaquil, surrounds the Gallapagos Islands on the Equator itself, and pulls their temperature down ten degrees; then it flows on westward with the great equatorial stream, assisted by the winds. In the desert of Lower Peru, at a few feet above the water, the cold occasioned by this polar current is quite unmistakable, and, at one season of the year, it yields up fogs for months, at Lima, called the Garua, which make the morning sun look like a moon, vanish soon after mid-day, and leave heavy dews at night. Ships on the coast, especially between Pisco and Lima, can take no observation of the shore, and the current, hurried on by the impediment it meets, frequently carries them beyond their destination. Sixteen hundred miles from Valparaiso to Callao, wind and current favoring, will be an eight or nine days' sail; but from Callao back to Valparaiso it is a voyage frequently of weeks or months.

The great equatorial current, flowing westward, contains the whole of the Antarctic drift, except so much of it as slipped out of the Pacific round Cape Horn, fed, of course, by currents from the North Pole also. This mighty mass of water, occupying a third part of the distance from Pole to Pole, runs through the great sieve of islands between Australia and China, part of it being also deflected northward in a warm current along the southeastern borders of Japan.

Now we will follow it into the Indian Ocean; but before leaving the Pacific, we may make note of a fact, that the advantage of steam over sailing-vessels is nowhere so enormous as it must be on the coast of Chili and Peru. A steamer leaving Guyaquil four weeks after a sailing-vessel, can reach Lima first.

The currents in the Indian Ocean are inextricably complicated with the winds; and if the winds expect attention just at present, they may whistle for it. It is enough to say that the great equatorial stream still pouring westward strikes against the coast of Africa, and finding that it has no thoroughfare, pours southward on each side of Madagascar, and doubles the Cape in the Agulhas or Cape current, outside which a counter-current flows back out of the Atlantic. The stream of water having passed the Cape, turns northward, is deflected by the shape of the land between Benin and Sierra Leone, not from the land, but from the edge of a returning stream that coasts it. It is to be remembered, also, that it follows its own bent in this deflection, flowing westward, as the main equatorial current, with a speed of, in some places, thirty, and in some places seventy-eight, miles a day. After giving off a northwest branch, and having a temperature now of seventy-nine degrees under the Equator, the main current strikes the east prominence of South America, at Cape St. Roque. This causes it to split. A southerly branch coasts in the direction of Cape Horn, and goes home to the Pacific, tired of travel; but the rest, pouring along northward, flows through the West India Islands into the Gulf of Mexico, a hollow excavated by its stream. It is of course to be understood that the outline of land is not caused only by the action of the currents; it is determined, also, by the geological character of soil; the loose soils wear away, while rocks oppose a barrier. The West India Islands are nothing more than those hard rocky parts of an old coast-line, which have withstood the constant action of a current which has been at work for ages, eating through the softer parts; so it has made a great bite in the Gulf of Mexico, and left us the West India Islands sprinkled about, as bones that proved too hard for its diges

tion. In the Gulf of Mexico, encompassed by land, the water, which has for a long time been acquiring warmth, offers the greatest contrast to the frosty state in which it set out on its journey. Near the mouth of the Mississippi its temperature reaches eighty-nine degrees. If you have a thermometer which enables you to warm a little water to that point, you have only to put your finger into the warm water, and so accurately feel how far we are now from the gnawing cold of the South Pole. As the stream flows constantly into the Gulf, it must, of course, also constantly flow out. It flows out between Florida and Cuba, being now called the gulf-stream. This coasts northward, having a cold counter-current between it and the shore, and crosses the Atlantic south of the great bank of Newfoundland, most of it turning southward to return by a set of countercurrents home. A branch from it, Rennel's Current, touches the Irish coast, and makes a circuit in the Bay of Biscay, sending a weak offshoot on its passage up the Irish Channel. Thus a drop of water from the South Pole, travelling by the extensive route we have just indicated, may be shaken from the head of the stout gentleman, who at last consents to get into his bathing machine.

Little less interesting than Harvey's old disovery of the circulation of the blood, is this discovery which has been made piecemeal in our own day of the circulation of the water. Though the great system is not yet anatomized in all its parts and we are puzzled, for example, here and there with portions of a vein or counter-current not yet properly accounted for-still we have laid bare the main artery, and found the water's heart in the great Southern Occan. It is there, not only because the intense cold of the south polar continent determines action in that direction; but because there is there also a wide expanse of sca

-the widest on the globe-susceptible of all impressions. The Pacific is full of natural breakwaters, reefs, shoals, and islands. At the North Pole, though there is indeed no continent, but water, at the Pole itself, the lands of Europe, Asia, and America, destroy the general expanse. In the enormous reservoir of water which surrounds the lofty continent of the South Pole we find the heart of the great circulating system; and not only do the grandest ocean currents take their rise in it, but in it, also, as we shall see presently, commences the pulsation of the tidal wave.

You observe that the great world of water serves not only as a home for countless forms of life, but that to us land creatures it serves also as an apparatus for the regulation of our climates. Cold currents come to limit the sun's monarchy, and warm streams flow to melt the icebergs where they travel out of bounds, and to prevent Jack Frost from annexation.

That is not all, nor nearly all. One characteristic of the works of Nature is continually to be recognized. Man makes a beautiful machine, worthy of admiration, in which many wheels and teeth combine, perhaps to make a piece of lace; it will make only lace, and nothing else. The works of nature are, incomparably, more simple, and yet there is nothing so minute as to be created for one purpose only. The earth's axis is inclined a little to one side;our polar ice, our long days and short days, spring, summer, autumn, winter, with the myriad of phenomena in their train, are the consequence—nor is that all. But we shall have quite enough to do if we confine, at present, our attention to the world of water. It is enough to say, that, in its way, a blade of grass, or lump of dirt, no less than the great sea, heaps use on use, and proof on proof of a Sublime Intelligence.