authorities interpreted Hercules’ victory over the river god of the Achelous as the embankment of that stream and the draining of its inundated delta tract by the national benefactor.[613] So the Chinese, whose land abounds in swamps and devastating rivers, have a long list of engineer heroes who embanked and drained for the salvation and benefit of mankind.  It is highly probable that the communal work involved in the construction of dikes and canals for the control of the Hoangho floods cemented the Chinese nationality of that vast lowland plain, and supplied the cohesive force that developed here at a very remote period a regularly organized state and an advancing civilization.

[Sidenote:  Control of water as factor in early civilizations of arid lands.]

The history of Egypt shows a similar effect of the yearly inundation of the Nile Valley.  Here, as in all rainless countries where irrigation must be practiced, the water becomes a potent factor of political union and civilization.  Its scarcity necessitates common effort in the construction and maintenance of irrigation works, and a central control to secure fair distribution of the water to the fields of the inhabitants.  A stimulus to progress is found in the presence of a problem, perennial as the yearly threatenings of the Hoangho, which demands the application of human intelligence and concerted labor for its solution.  Additional arable land for the growing population can be secured only by the wider distribution of the fructifying water; this in turn depends upon corporate effort wisely directed and ably controlled.  Every lapse in governmental efficiency means an encroachment of the desert upon the alluvial fields and finally to the river bank, as to-day in Mesopotamia.

The fact that the earliest civilizations have originated in the sub-tropical rainless districts of the world has been ascribed solely to the regular and abundant returns to tillage under irrigation, as opposed to the uncertain crops under variable meteorological conditions; to the consequent accumulation of wealth, and the emancipation of man for other and higher activities, which follows his escape from the agricultural vicissitudes of an uncertain climate.  When Draper says:  “Civilization depends on climate and agriculture,” and “the civilization of Egypt depended for its commencement on the sameness and stability of the African climate,” and again, “agriculture is certain in Egypt and there man first became civilized,"[614] he seizes upon the conspicuous fact of a stable food supply as the basis of progress, failing to detect those potent underlying social effects of the inundations—­social and political union to secure the most effective distribution of the Nile’s blessings and to augment by human devices the area accessible to them, the development of an intelligent water economy, which ultimately produced a long series of intellectual achievements.[615]

[Sidenote:  Cultural areas in primitive America.]