[Sidenote:  Effect of early maritime migration.]

Even early maritime migrants did not keep their strains pure.  The untried navigator sailing from island to headland, hugging the coast and putting ashore for water, came into contact with the natives.  Cross currents of migration can be traced in Polynesian waters, where certain islands are nodal points which have given and received of races and culture through centuries of movement.  The original white population of Uruguay differed widely from that of the other Spanish republics of South America.  Its nucleus was a large immigration of Canary Islanders.  These were descendants of Spaniards and the native Guanches of the Canaries, mingled also with Norman, Flemish and Moorish blood.[153] The Norse on their way to Iceland may have picked up a Celtic element in the islands north of Scotland; but from the Faroe group onward they found only empty Iceland and Greenland.  This was an exceptional experience.  Early navigation, owing to its limitations, purposely restricted itself to the known.  Men voyaged where men had voyaged before and were to be found.  Journeys into the untenanted parts of the world were rare.  However, the probable eastward expansion of the Eskimo along the Arctic rim of North America belongs in this class, so that this northern folk has suffered no modification from contact with others, except where Alaska approaches Asia.

[Sidenote:  The transit land.]

The land traversed by a migrating horde is not to be pictured as a dead road beneath their feet, but rather as a wide region of transit and transition, potent to influence them by its geography and people, and to modify them in the course of their passage.  The route which they follow is a succession of habitats, in which they linger and domicile themselves for a while, though not long enough to lose wholly the habits of life and thought acquired in their previous dwelling place.  Although nature in many places, by means of valleys, low plains, mountain passes or oasis lines, points out the way of these race movements, it is safer to think and speak of this way as a transit land, not as a path or road.  Even where the district of migration has been the sea, as among the Caribs of the Antilles Islands, the Moros of the Philippines, and the Polynesians of the Pacific, man sends his roots like a water plant down into the restless element beneath, and reflects its influence in all his thought and activities.

[Sidenote:  War as a form of the historical movement.]

Every aggressive historical movement, whether bold migration or forcible extension of the home territory, involves displacement or passive movement of other peoples (except in those rare occupations of vacant lands), who in turn are forced to encroach upon the lands of others.  These conditions involve war, which is an important form of the historical movement, contributing to new social contacts and fusion of racial stocks.  Raids and piratical descents are