In these last six chapters we have traced in outline the whole process by which, in the course of 5000 or 6000 years--that is to say, in something between 150 and 200 generations--mankind passed from the stage of early Neolithic husbandry, in which the primitive skin-clad family tribe reaped and stored in their rude mud huts the wild-growing fodder and grain-bearing grasses with sickles of stone, to the days of the fourth century B.C., when all round the shores of the Mediterranean and up the Nile, and across Asia to India, and again over the great alluvial areas of China, spread the fields of human cultivation and busy cities, great temples, and the coming and going of human commerce. Galleys and lateen-sailed ships entered and left crowded harbours, and made their careful way from headland to headland and from headland to island, keeping always close to the land. Phœnician shipping under Egyptian owners was making its way into the East Indies and perhaps even further into the Pacific. Across the deserts of Africa and Arabia and through Turkestan toiled the caravans with their remote trade; silk was already coming from China, ivory from Central Africa, and tin from Britain to the centres of this new life in the world. Men had learnt to weave fine linen[156] and delicate fabrics of coloured wool; they could bleach and dye; they had iron as well as copper, bronze, silver, and gold; they had made the most beautiful pottery and porcelain; there was hardly a variety of precious stone in the world that they had not found and cut and polished; they could read and write; divert the course of rivers, pile pyramids, and make walls a thousand miles long. The fifty or sixty centuries in which all this had to be achieved may seem a long time in comparison with the threescore and ten years of a single human life, but it is utterly inconsiderable in comparison with the stretches of geological time. Measuring backward from these Alexandrian cities to the days of the first stone implements, the _rostro-carinate_ implements of the Pliocene Age, gives us an extent of time fully a hundred times as long.