The Indian Ocean produced a civilization of its own,
with which it colored a vast semi-circle of land reaching from Java to
Abyssinia, and more faintly, owing to the wider divergence of race, the
further stretch from Abyssinia to Mozambique.

Thus the northern Indian Ocean, owing to its form, its location in the
angle between Asia and Africa and the latitude where, round the whole
earth, "the zone of greatest historical density" begins, and especially
its location just southeast of the Mediterranean as the eastern
extension of that maritime track of ancient and modern times between
Europe and China, has been involved in a long series of historical
events. From the historical standpoint, prior to 1492 it takes a far
higher place than the Atlantic and Pacific, owing to its nature as an
enclosed sea.[575] But like all such basins, this northern Indian Ocean
attained its zenith of historical importance in early times. In the
sixteenth century it suffered a partial eclipse, which passed only with
the opening of the Suez Canal. During this interval, however, the
Portuguese. Dutch and English had rounded the Cape of Good Hope and
entered this basin on its open or oceanic side. By their trading
stations, which soon traced the outlines of its coasts from Sofala in
South Africa around to Java, they made this ocean an alcove of the
Atlantic, and embodied its events in the Atlantic period of history. It
is this open or oceanic side which differentiates the Indian Ocean
physically, and therefore historically, from a genuine enclosed sea.

[Sidenote: Limitation of small area in enclosed seas.]

The limitation of every enclosed or marginal sea lies in its small area
and in the relatively restricted circle of its bordering lands. Only
small peninsulas and islands can break its surface, and short stretches
of coast combine to form its shores. It affords, therefore, only limited
territories as goals for expansion, restricted resources and populations
to furnish the supply and demand of trade. What lands could the
Mediterranean present to the colonial outlook of the Greeks comparable
to the North America of the expanding English or the Brazil of the
Portuguese? Yet the Mediterranean as a colonial field had great
advantages in point of size over the Baltic, which is only one-sixth as
large (2,509,500 and 431,000 square kilometers respectively), and
especially over the Red Sea and Persian Gulf, whose effective areas were
greatly reduced b