before Industrialism (which may repeople it) began. The _Sawâd_ was first reclaimed by men who had already a mastery of metals, a system of writing, and a mature religion--less civilised men would never have attempted the task. These Sumerians, in the fourth millennium B.C., lived on _tells_ heaped up above flood-level, each _tell_ a city-state with its separate government and gods, for centralisation was the one thing needful to the country which the Sumerians did not achieve. The centralisers were Semites from the Arabian plateau. Sargon of Akkad and Naram Sin ruled the whole _Sawâd_ as early as 2500 B.C.; Hammurabi, in 1900, already ruled it from Babylon; and the capital has never shifted more than sixty miles since then. Babylon on the Euphrates and Bagdad on the Tigris are the alternative points from which the _Sawâd_ can be controlled. Just above them the first irrigation canals branch off from the rivers, and between them the rivers approach within thirty-five miles of each other. It is the point of vantage for government and engineering. Here far-sighted engineers and stronghanded rulers turned the waters of Babylon into waters of life, and the _Sawâd_ became a great heart of civilisation, breathing in man-power--Sumerians and Amorites and Kassites and Aramaeans and Chaldeans and Persians and Greeks and Arabs--and breathing out the works of man--grain and wool and Babylonish garments, inventions still used in our machine-shops, and emotions still felt in our religion. "The land," writes Herodotus[52], who saw it in its prime, "has a little rain, and this nourishes the corn at the root; but the crops are matured and brought to harvest by water from the river--not, as in Egypt, by the river flooding over the fields, but by human labour and _shadufs_[53] For Babylonia, like Egypt, is one network of canals, the largest of which is navigable. It is far the best corn-land of all the countries I know. There is no attempt at arboriculture--figs or vines or olives--but it is such superb corn-land that the average yield is two-hundredfold, and three-hundredfold in the best years. The wheat and barley there are a good four inches broad in the blade, and millet and sesame grow as big as trees--but I will not state the dimensions I have ascertained, because I know that, for anyone who has not visited Babylonia and witnessed these facts about the crops for himself, they would be altogether beyond belief." Harnessed in the irrigation channels, the Tigris and Euphrates had become as mighty forces of production as the Nile and the Ganges, the Yangtse and the Hoang-Ho.