Fan-like, the Gulf Stream spreads as it journeys, growing gradually wider and wider, shallower and shallower, cooler and cooler--yet the last so slowly that, even off the coast of Scotland, water nine hundred fathoms deep is found to be at 40° F. How strongly this mass of warm water affects the air above it is well known to sailors. When passing from the stream to the outside ocean, or from the ocean to the stream, they often change in a few hours from a warm to a cool or from a cool to a warm climate. The atmosphere is ever ready to tune its mood sympathetically to that of the ocean over which it sweeps. We know well in Great Britain that our soft south-west breezes seldom fail to bring us warmth; though we do not always remember the debt that we owe to our friend the Gulf Stream. But for the immense stores of heat carried northward, and given over to us, our Island climate would be different indeed from what it now is. That is why our fellow-subjects in eastern and central Canada, living no farther from the equator than we do ourselves, suffer from an intensity of cold in winter which we never endure. It is difficult to realise that parts of ice-bound Labrador and of Canada, where the thermometer often drops to 40° below zero, are no farther north than London and Paris; while Newfoundland lies actually more to the south than Erin’s green Isle. Turning to the Pacific Ocean, we find there a corresponding river, again flowing to the north-east. Just as the Gulf Stream wanders across the Atlantic, so this river wanders over the Pacific, carrying stores of tropical warmth to opposite coasts. At its quickest, it is less rapid than the Gulf Stream, and about three times as wide. It too, as it journeys, becomes gradually broader, shallower, slower, colder. This “Kuro Sivo” or “Black Stream,” so named from its dark colour, flows outside Japan, and then strikes freely for the northern coasts of North America. And because of its work as a winter heating apparatus in Alaska, the humming bird is found at a latitude which, on the other side of the American Continent, means, not the play and whirr of humming-birds in a soft air, but the disporting of walruses among ice-floes. As in the Atlantic, so in the Pacific, the warm northward-travelling current is balanced by a cold southward-travelling current. The Arctic stream of the Pacific is not so marked as that of the Atlantic, perhaps partly because of the much shallower outlet from the Arctic Ocean; still it is quite chilly enough in its effects upon the Siberian climate. Here again the cold stream acts as a “wall” to the warm river flowing the other way.