The problem of population great stretches of soft sand, making the road difficult. To the north of the oases lay a belt of sand, and then an immense gravel and lava plain, filling up everything between the eastern edge of Syria and the banks of the Euphrates where Mesopotamia began. The practicability of this northern desert for men and motor-cars enabled the Arab revolt to win its ready success.
The hills of the west and the plains of the east were the parts of Arabia always most populous and active. In particular on the west, the mountains of Syria and Palestine, of Hejaz and Yemen, entered time and again into the current of our European life. Ethically, these fertile healthy hills were in Europe, not in Asia, just as the Arabs looked always to the Mediterranean, not to the Indian Ocean, for their cultural sympathies, for their enterprises, and particularly for their expansions, since the migration problem was the greatest and most complex force in Arabia, and general to it, however it might vary in the different Arabic districts.
In the north (Syria) the birth rate was low in the cities and the death rate high, because of the insanitary conditions and the hectic life led by the majority. Consequently the surplus peasantry found openings in the towns, and were there swallowed up. In the Lebanon, where sanitation had been improved, a greater exodus of youth took place to America each year, threatening (for the first time since Greek days) to change the outlook of an entire district.
In Yemen the solution was different. There was no foreign trade, and no massed industries to accumulate population in unhealthy places. The towns were just market towns, as clean and simple as ordinary villages. Therefore the population slowly increased; the scale of living was brought down very low; and a congestion of numbers was generally felt. They could not emigrate overseas; for the Sudan was even worse country than Arabia, and the few tribes which did venture across were compelled to modify their manner of life and their Semitic culture profoundly, in order to exist. They could not move northward along the hills; for these were barred by the holy town of Mecca and its port Jidda: an alien belt, continually reinforced by strangers from India and Java and Bokhara and
Africa, very strong in vitality, violently hostile to the Semitic consciousness, and maintained despite economics and geography and