[Sidenote:  North Sea and Baltic basins.]

The same thing has come to pass in the North Sea.  Originally Celtic on its western or British side, as opposed to its eastern or Germanic coast, it has been wholly Teutonized on that flank also from the Strait of Dover to the Firth of Tay, and sprinkled with Scandinavian settlers from the Firth of Tay northward to Caithness.[557] The eleventh century saw this ethnic unification achieved, and the end of the Middle Ages witnessed the diffusion of the elements of a common civilization through the agency of commerce from Bruges to Bergen.  The Baltic, originally Teutonic only on its northern and western shores, has in historical times become almost wholly Teutonic, including even the seaboard of Finland and much of the coast provinces of Russia.[558] Unification of civilization attended this unification of race.  In its period of greatest historical significance from the twelfth to the seventeenth century, the Baltic played the role of a northern Mediterranean.[559] The countless shuttles of the Hanse ships wove a web of commercial intercourse between its remotest shores.  Novgorod and Aboe were in constant communication with Luebeck and Stralsund;[560] and Wisby, on the island of Gotland at the great crossroads of the Baltic,[561] had the focal significance of the Piraeus in ancient Aegean trade.

[Sidenote:  Bering Sea.]

If we turn to Asia, we find that even the unfavorable Arctic location of Bering Sea has been unable to rob it entirely of historical significance.  This is the one spot where a native American race has transplanted itself by its natural expansion to Asiatic shores.  The circular rim and island-dotted surface have guided Eskimo emigrants to the coast of the Chukchian Peninsula, where they have become partly assimilated in dress and language to the local Chukches.[562] The same conditions also facilitated the passage of a few Chukches across Bering Strait to the Alaskan side.  At Pak (or Peck) on East Cape and on Diomed Island, situated in the narrowest part of Bering Strait, are the great intercontinental markets of the polar tribes.  Here American furs have for many decades been exchanged for the reindeer skins of northern Siberia and Russian goods from far-away Moscow.[563] Only the enclosed character of the sea, reported by the Danish explorer Vitus Bering, tempted the land-bred Russians, who reached the northeastern coast of Siberia at the middle of the eighteenth century, to launch their leaky boats of unseasoned timber, push across to the American continent, and make this whole Bering basin a Russian sea;[564] just as a few decades before, when land exploration of Kamchatka had revealed the enclosed character of the Sea of Okhotsk, the Russian pioneers took a straight course across the water to their Pacific outpost of Petropavlovsk near the southern end of the peninsula.  But even before the coming of the Slavs to its shores, the Sea of Okhotsk seems to have been an area of native commercial and ethnic intercourse from the Amur River in Siberia in a half circle to the east, through Sakhalin, Yezo, the Kurile Islands and southern Kamchatka,[565] noticeably where the rim of the basin presented the scantiest supply of land and where, therefore, its meager resources had to be eked out by fisheries and trade on the sea.