The north of the chain, from the Kuriles to Formosa, belongs to the empire of Japan; southward it is continued by the Philippines (belonging to the United States of America) which link it with the vast archipelago between the Pacific and Indian oceans, to which the name Malay Archipelago is commonly applied.
In1522-1524various voyages of discovery were made on the west coast of America, partly in the hope of finding a strait connecting the two oceans to the region of the central isthmus.
In the oceans alone there are estimated to be 1141 X 10 12 tons of sulphate, K 2 SO 4, but this inexhaustible store is not much drawn upon; and the "salt gardens" on the coast of France lost their industrial importance as potash-producers since the deposits at Stassfurt in Germany have come to be worked.
America, broadening in the north as if to span the oceans by reaching to its neighbours on the east and west, tapering between vast oceans far to the south where the nearest land is in the little-known Antarctic regions, roughly presents the triangular outline that is to be expected from tetrahedral warping; and although greatly broken in the middle, and standing with the northern and southern parts out of a meridian line, America is nevertheless the best witness among the continents of to-day to the tetrahedral theory.
The relation of the Americas to each other and to the rest of the world, as the home of plants and animals, is greatly affected by the breadth of the adjacent oceans, and also by the geologically recent changes of altitude whereby the breadth of the narrower parts of the lands and the oceans has been significantly altered.