[Sidenote:  Importance of zonal and continental location.]

The historical significance of an enclosed sea basin depends upon its zonal location and its position in relation to the surrounding lands.  We observe a steady decrease of historical importance from south to north through the connected series of the Yellow, Japan, Okhotsk, Bering Seas and the Arctic basin, miscalled ocean.  The far-northern location of the Baltic, with its long winters of ice-bound ports and its glaciated lands, retarded its inclusion in the field of history, curtailed its important historical period, and reduced the intensity of its historical life, despite the brave, eager activity of the Hanseatic League.  The Mediterranean had the advantage, not only of a more favorable zonal situation, but of a location at the meeting place of three continents and on the line of maritime traffic across the eastern hemisphere from the Atlantic to the Pacific.

[Sidenote:  Thalassic character of the Indian Ocean.]

These advantages it shares in some degree with the Indian Ocean, which, as Ratzel justly argues, is not a true ocean, at best only half an ocean.  North of the equator, where it is narrowed and enclosed like an inland sea, it loses the hydrospheric and atmospheric characteristics of a genuine ocean.  Currents and winds are disorganized by the close-hugging lands.  Here the steady northeast trade wind is replaced by the alternating air currents of the northeast and southwest monsoons, which at a very early date[573] enabled merchant vessels to break away from their previous slow, coastwise path, and to strike a straight course on their voyage between Arabia or the east coast of Africa and India.[574] Moreover, this northern half of the Indian Ocean looks like a larger Mediterranean with its southern coast removed.  It has the same east and west series of peninsulas harboring differentiated nationalities, the same northward running recesses, but all on a larger scale.  It has linked together the history of Asia and Africa; and by the Red Sea and Persian Gulf, it has drawn Europe and the Mediterranean into its sphere of influence.  At the western corner of the Indian Ocean a Semitic people, the Arabs of Oman and Yemen, here first developed brilliant maritime activity, like their Phoenician kinsmen of the Lebanon seaboard.  Similar geographic conditions in their home lands and a nearly similar intercontinental location combined to make them the middlemen of three continents.  Just as the Phoenicians, by way of the Mediterranean, reached and roused slumberous North Africa into historical activity and became the medium for the distribution of Egypt’s culture, so these Semites of the Arabian shores knocked at the long-closed doors of East Africa facing on the Indian basin, and drew this region into the history of southern Asia.  Thus the Africa of the enclosed seas was awakened to some measure of historical life, while the Africa of the wide Atlantic slept on.