As to the Alpine glaciers, M. Forel reports from data he has collected that there have been several enlargements and diminutions during the last century. And since 1875 enlargements have taken place, their shrinkage being caused by warm and dry weather, while their enlargement was brought about during cold and rainy seasons. The glaciers of Alaska cannot attain much extension until the waters of the great Japanese stream acquire a lower temperature. There is at this date a small current setting down through the eastern side of Bering Strait, bearing field-ice in the spring season down to Anadyr Gulf. The Okhotsk Sea in the spring season furnishes considerable field-ice to cool the north Pacific waters, and the wintry winds which sweep down from the high lands of Northern Asia also serve to chill the Pacific seas; but all such sources of cold combined at this age have but little general effect on the vast Japanese current, which still has warmth sufficient to prevent the increase of glaciers on Alaska. This great ocean stream in its impact against the shores of Oregon causes a high sea-level, which is mostly turned southward by the prevailing north-west winds. Still, a comparatively small stream sets along the shore of the Alaska Gulf, and also through the island passages toward a slight low sea-level, to the leeward of the Alaska peninsula; and it is probable that this current which warms these in-shore waters is favored by the difference of temperature and density between the waters abreast Oregon and the Gulf of Alaska, and it may be owing to the same cause that a small stream is sent along the eastern shore of Bering Strait into the deep portions of the Arctic Ocean. Thus because of the warm waters that proceed from the great Japanese current the glaciers of Alaska are prevented from increasing their bulk. The only way to furnish the Japanese stream with colder water, and so cause glaciers to increase on the north-west coast of America, is through the great Humboldt current, which has its rise in the southern ocean west of Patagonia and the Cape Horn channel, where a moderate but vast high sea-level is formed on account of the great drift current of the southern ocean being somewhat obstructed on its passage through the Cape Horn channel, which is about one-third the breadth of the westerly wind-belt.