The last rulers of the Chow Dynasty were ousted by the kings of Ts’in, the latter seized upon the sacred sacrificial bronze tripods, and so were able to take over the imperial duty of offering sacrifices to Heaven. In this manner was the Ts’in Dynasty established. It ruled with far more vigour and effect than any previous family. The reign of Shi-Hwang-ti (meaning “first universal emperor”) of this dynasty is usually taken to mark the end of feudal and divided China. He seems to have played the unifying rôle in the east that Alexander the Great might have played in the west, but he lived longer, and the unity he made (or restored) was comparatively permanent, while the empire of Alexander the Great fell to pieces, as we shall tell, at his death. Shi-Hwang-ti, among other feats in the direction of common effort, organized the building of the Great Wall of China against the Huns. A civil war followed close upon his reign, and ended in the establishment of the Han Dynasty. Under this Han Dynasty the empire grew greatly beyond its original two river valleys, the Huns were effectively restrained, and the Chinese penetrated westward until they began to learn at last of civilized races and civilizations other than their own. By 100 B.C. the Chinese had heard of India, their power had spread across Tibet and into Western Turkestan, and they were trading by camel caravans with Persia and the western world. So much for the present must suffice for our account of China. We shall return to the distinctive characters of its civilization later. § 6 And in these thousands of years during which man was making his way step by step from the barbarism of the heliolithic culture to civilization at these old-world centres, what was happening in the rest of the world? To the north of these centres, from the Rhine to the Pacific, the Nordic and Mongolian peoples, as we have told, were also learning the use of metals; but while the civilizations were settling down these men of the great plains were becoming migratory and developing from a slow wandering life towards a complete seasonal nomadism. To the south of the civilized zone, in central and southern Africa, the negro was making a slower progress, and that, it would seem, under the stimulus of invasion by whiter tribes from the Mediterranean regions, bringing with them in succession cultivation and the use of metals. These white men came to the black by two routes: across the Sahara to the west as Berbers and Tuaregs and the like, to mix with the negro and create such quasi-white races as the Fulas; and also by way of the Nile, where the Baganda (= Gandafolk) of Uganda, for example, may possibly be of remote white origin. The African forests were denser then, and spread eastward and northward from the Upper Nile.