and cultural rank than the black races of Australia and Melanesia; and for this difference one cause at least is to be found in the difference of their habitats.  The knowledge of iron, stock-raising, and many branches of agriculture were continental achievements, which belonged to the great eastern land-mass and spread from Egypt over Africa even to the Hottentot country; the lack of them among the Australians must be attributed to their insularity, which barred them from this knowledge, just as the ignorance of iron and other metals among the native Canary Islanders[883] can only be ascribed to a sea barrier fifty-two miles wide.  The scant acquaintance of the Balearic Islanders with iron in Roman days[884] points to insular detachment.  The lack of native domesticable animals in the Pacific archipelagoes illustrates another limitation incident to the restricted fauna of islands, though this particular lack also retarded the cultural development of primitive North America.

[Sidenote:  Later stimulation of development.]

On the other hand, people who have already secured the fundamental elements of civilization find the partial seclusion of an island environment favorable to their further progress, because it permits their powers to unfold unhindered, protects them from the friction of border quarrels, from the disturbance and desolation of invading armies, to which continental peoples are constantly exposed.  But even here the advantage lies in insulation but not in isolation,[885] in a location like that of England or Japan, near enough to a continent to draw thence culture, commerce and occasional new strains of blood, but detached by sea-girt boundaries broad enough to ward off overwhelming aggressions.  Such a location insures enough segregation for protection, but also opportunity for universal contact over the vast commons of the sea.

[Sidenote:  Excessive isolation.]

Excessive isolation may mean impoverishment in purse and progress even for an advanced race.  Ireland has long suffered from its outskirt location.  It lies too much in the shadow of England, and has been barred by the larger island from many warming rays of immigration, culture and commerce that would have vitalized its national existence.  The “round barrow” men of the Bronze Age, the Romans, and the Normans never carried thither their respective contributions to civilization.  The Scandinavians infused into its population only inconsiderable strains of their vigorous northern blood.[886] In consequence the Irish are to-day substantially the same race as in Caesar’s time, except for the small, unassimilated group of antagonistic English and Lowland Scotch, both Teutonic, in Ulster.[887] Barred by Great Britain from direct contact with the Continent and all its stimulating influences, suffering from unfavorable conditions of climate and topography, Ireland’s political evolution progressed at a snail’s pace.  It tarried in the tribal stage till after the English