such as the eligibility of elevated, or sterile, or sparsely peopled tracts for Frontier purposes, have not been without influence in their selection. Of political or historical Frontiers I may mention as illustrations the Frontiers of Spain and Portugal, of Germany and Holland, of Germany and Austria, of Russia and Germany, of France and Germany (except the Vosges), of France and Belgium, of Belgium and Holland, of Turkey and Greece. Here and there exists a State like Switzerland, which accords with no one principle of national distribution, or Belgium, which infringes them all. Both are the creations of expediency or of fear. In Asiatic Frontier delineations tribal boundaries, except where overridden by political considerations, are apt to be observed.
In the last quarter of a century, largely owing to the international scramble for the ownerless or undefended territories of Africa and Asia, fresh developments have occurred in the expansion of Frontiers, of which notice must here be taken. The result may be much the same as in the ruder days of Alexander or Trajan or Justinian, when there was no sanction beyond that of might; modern usage, however, evolves with convenient rapidity a Law of Nations that is held to justify these more recent manifestations of the centripetal tendency of international borders. All the expedients to which I am about to refer are variations in differing stages of the doctrine of Protectorates which has existed from the remotest days of Empire.
A Protectorate is a plan adopted for extending the political or strategical as distinct from the administrative