interposition of the sea that England lost America; that the Dutch and Portuguese lost the greater part of their Indian Empires; that Napoleon, equally with Rome, experienced so many difficulties in Egypt; that the Mexican adventure of France and Austria ended in fiasco; that Spain was robbed almost in a day of her possessions in Cuba, Porto Rico, and the Philippines. In these circumstances the continued connexion of the parent State with her transmarine possessions—which might seem to be an impossible aspiration—is only maintained in modern times by the grant of some form of self-government with a view to attaching the inhabitants of the colony or possession to the seat of imperial authority.
Second in the list of Natural Frontiers may be placed deserts, until modern times a barrier even more impassable than the sea. Asia and Africa afford the best known instances of this phenomenon. For centuries China has been protected by the great Gobi Desert on her north-west border; Samarkand and Bokhara were shielded by the sandhills of the Kara Kum; the Indus valley was severed from the rest of India in its southerly portions by the Sind Desert, while Beluchistan is still safeguarded by the waste that stretches from Nushki to Seistan. Syria found a natural Frontier on the east in the desert that bears her name. Indeed, the whole of western Asia, that part, in fact, which was exposed to Hellenic influences was for centuries cut off from India by the broad wastes of Persia and Turkestan. Egypt, protected on the west by the impassable barrier of the Libyan Desert, and on the east by the desert of the Sinaitic peninsula, has retained a physical identity almost unequalled in history. It was of her eastern