GULF STREAM AND OCEAN-CURRENTS. The most important and best known .of the great ocean-currents derives its name from the gulf, of Mexico, Out of which it flows, between the coast of Florida on the one side, and the Cuba and the Bahama Islands and shoals on the other. With is breadth of about 50 in. in its narrowest portion, it has a velocity at times of 5 m. an hour, pouring along like an immense torrent. This great ocean-river flows in a north-easterly direction along the American coast, gradually widening its current and diminishing in velocity, until it reaches the island and banks of Newfoundland, when it sweeps across the Atlantic, and divides into two portions, one of which turns eastward towards the Azores and coast of Morocco, while the other laves the shores of the British islands and Norway, and can be perceived on the southern borders of Iceland and Spitzbergen, nearly as far c. as Nova Zembla.
The waters of the gulf stream are of a deep indigo blue, with boundaries sharply defined against the light green of the seas through which it passes in its early course. It abounds with masses of sea-weed, torn from the coral rocks of the strait throiigh which it passes when it has its greatest power and velocity; while in its warm current may be seen myriads of fish and of animalculm. As this great stream pours out of the gulf of Mexico, it has a warmth of 8V in summer, being 4° higher than that of the ocean at the equator. In mid-Atlantic, opposite Nova Scotia, it has fallen at all seasons only about 14'; while the British islands and north-western coasts of Europe, at a distance of 4,000 w. from the gulf, are bathed with waters heated under a tropical sun, and have their temperatures raised iu winter about 30° above the normal temperature of the lati tudes. In mid-winter, off the inclement coasts of America, between cape Hatteras and Newfoundland, ships beaten hack from theirharbors by fierce north-westers, until loaded down with ice and in danger of foundering, turn their prows to the c. and seek relief and comfort in the gulf stream. A bank of fog rising like a wall, caused by the con densation of warm vapors meeting a colder atmosphere, marks the edge of the stream.
The water suddenly changes from green to blue, the climate from winter to summer; and this change is so sudden, that when a ship is crossing the line, a difference of 30' of temperature has been marked between the bow and the stern.
The great differences of temperature between the western shores of Europe and the eastern shores of America have been attributed, too largely, perhaps, to the influence of the gulf stream. There is no doubt that such an immense body of heated water in the north-eastern Atlantic must raise the temperature ot the atmosphere, and that to this importation of the effects of tropical sunshine by sea is due, to a certain extent, Ireland's perpetual green, the soft, moist climate of England and Scotland, and the fact that the harbors of the western and northern coasts of Norway, as far e. as Varanger Fjord, remain open, when the Baltic, much further s., is a sheet of ice. England, clothed in perennial verdure, and Scotland, where the grass grows during 11 months of the year, are in the same latitude as the frozen and horrible coast of Labrador. Norway is opposite Greenland; and Lisbon, where frost is scarcely known, is in the same latitude as Washington, where the Potomac river, a mile in breadth, sometimes freezes over in a single night. This difference is to be ascribed, not to the gulf stream alone, but to that in conjunction with the prevailing south-westerly winds. The Mediterrauean, exposed to no cold currents from the arctic regions, bearing bergs and fields of ice, is a constant receiver and distributer of heat, and modifies the temperature of adjacent regions. North America, on the contrary, is exposed along its eastern shore to a great current from the polar seas, running inside and counter to the gulf stream, and coining Maded with ice from the northern regions; and while the continent narrows towards the tropics, it grows broad in the polar regions, from which come the cold northwesters, the pre vailing winds during the wintry season.