butes.[612] [See map page 8.]

[Sidenote: Social gain by control of the water.]

In such organized struggles to reduce the domain of the water and extend
that of the dry land, the material gain is not all: more significant by
far is the power to co-operate that is developed in a people by a
prolonged war against overwhelming sea or river. A common natural
danger, constantly and even regularly recurring, necessitates for its
resistance a strong and sustained union, that draws men out of the
barren individualism of a primitive people, and forces them without halt
along the path of civilization. It brings a realizing sense of the
superiority of common interests over individual preferences, strengthens
the national bond, and encourages voluntary subservience to law.

This is the social or political gain; but this is not all. The danger
emanating from natural phenomena has its discoverable laws, and
therefore leads to a first empirical study of winds, currents, seasonal
rainfall and the whole science of hydraulics. With deep national
insight, the Greeks embodied in their mythology the story of Perseus and
his destruction of the sea monster who ravaged the coast, and Hercules'
killing of the many-headed serpent who issued from the Lernean Marshes
to lay waste the country of Argos. Even so early a writer as Strabo
states that yet earlier 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 cent