On examining other coast-lands, in different parts of the globe, we shall everywhere find the influence of the reigning currents producing analogous effects to those I have already mentioned.
The Southern Atlantic is not warmed like the European seas by tepid streams, it is exposed on all sides to the free afflux of the cold waters of the Antarctic Ocean, and during the summer months to the influence of drift ice. Thus, the southern extremity of America, Terra del Fuego, the Falkland Islands, South Georgia, Sandwich Land, and other isles of the southern ocean, have a much colder climate than the European coasts and islands situated under the same latitude.
Let us for instance compare the temperature of the Falkland Islands and of Port Famine in the Straits of Magellan, with that of Dublin, which is situated at an equal distance from the line.
Mean Temperature. Latitude. Winter. Summer. Annual.
Dublin 53° 21′ N. +4·0° R. 15·3° 9·6° Port Famine 53° 38′ S. +0·6 10·0 5·3 Falkland Islands 52° 0′ S. 4·36 11·8 8·24 Feroë Islands 62° 2′ N. 3·9 11·6 7·1
Thus the climate of the Falkland Islands is, as we see, not very different from that of the Feroë Islands, although the latter lie ten degrees farther from the equator.
In the Pacific Ocean, as well as in the Atlantic, we find a westerly current filling the whole breadth of the tropical zone, from the coast of America to that of Australia and the Indian Archipelago. The best known of its affluxes is the cold Peruvian stream, which, emerging from the Polar Sea, flows with great rapidity along the shores of Chili and Peru, and does not take a westerly direction, before reaching the neighbourhood of the line. It has everywhere a remarkably low temperature, comparatively to the latitude, and this sufficiently accounts for the equal and temperate climate on the coasts of Chili and Peru. Thus, the mean temperature of Callao (12° S. lat.) is only 20° R. while in Rio Janeiro (23° S. lat.), though so much farther from the line, the annual warmth rises to 23·2° R.
In the beginning of November, Humboldt found at Callao the temperature of the sea within the current not higher than 15·5°, while outside the stream it rose to 26° or even 28·5° R.