15. And remember, in all future study of the relations of these countries, you must never allow your mind to be disturbed by the accidental changes of political limit. No matter who rules a country, no matter what it is officially called, or how it is formally divided, eternal bars and doors are set to it by the mountains and seas, eternal laws enforced over it by the clouds and stars. The people that are born on it are its people, be they a thousand times again and again conquered, exiled, or captive. The stranger cannot be its king, the invader cannot be its possessor; and, although just laws, maintained whether by the people or their conquerors, have always the appointed good and strength of justice, nothing is permanently helpful to any race or condition of men but the spirit that is in their own hearts, kindled by the love of their native land. 16. Of course, in saying that the invader cannot be the possessor of any country, I speak only of invasion such as that by the Vandals of Libya, or by ourselves of India; where the conquering race does not become permanently inhabitant. You are not to call Libya Vandalia, nor India England, because these countries are temporarily under the rule of Vandals and English; neither Italy Gothland under Ostrogoths, nor England Denmark under Canute. National character varies as it fades under invasion or in corruption; but if ever it glows again into a new life, that life must be tempered by the earth and sky of the country itself. Of the twelve names of countries now given in their order, only one will be changed as we advance in our history;--Gaul will properly become France when the Franks become her abiding inhabitants. The other eleven primary names will serve us to the end. 17. With a moment's more patience, therefore, glancing to the far East, we shall have laid the foundations of all our own needful geography. As the northern kingdoms are moated from the Scythian desert by the Vistula, so the southern are moated from the dynasties properly called 'Oriental' by the Euphrates; which, "partly sunk beneath the Persian Gulf, reaches from the shores of Beloochistan and Oman to the mountains of Armenia, and forms a huge hot-air funnel, the base" (or mouth) "of which is on the tropics, while its extremity reaches thirty-seven degrees of northern latitude. Hence it comes that the Semoom itself (the specific and gaseous Semoom) pays occasional visits to Mosoul and Djezeerat Omer, while the thermometer at Bagdad attains in summer an elevation capable of staggering the belief of even an old Indian."[26] [Footnote 26: Sir F. Palgrave, 'Arabia,' vol. ii., p. 155. I gratefully adopt in the next paragraph his division of Asiatic nations, p. 160.]