adaptation to an alien and hostile element,
whose violent displays of power recurrently stimulated the human
adjustment between attack and defense.

Because adaptation to the sea has been vastly more difficult than to the
land, commensurate with the harder struggle it has brought greater
intellectual and material rewards. This conquest of the sea is entitled
to a peculiarly high place in history, because it has contributed to the
union of the various peoples of the world, has formed a significant part
of the history of man, whether that history is economic, social,
political or intellectual. Hence history has always staged its most
dramatic acts upon the margin of seas and oceans; here always the plot
thickens and gives promise of striking development. Rome of the seven
hills pales before England of the "Seven Seas."

[Sidenote: The sea in universal history.]

Universal history loses half its import, remains an aggregate of parts,
fails to yield its significance as a whole, if it does not continually
take into account the unifying factor of the seas. Indeed, no history is
entitled to the name of universal unless it includes a record of human
movements and activities on the ocean, side by side with those on the
land. Our school text-books in geography present a deplorable hiatus,
because they fail to make a definite study of the oceans over which man
explores and colonizes and trades, as well as the land on which he
plants and builds and sleeps.

The striking fact about the great World Ocean to-day is the manifold
relations which it has established between the dwellers on its various
coasts. Marine cables, steamer and sailing routes combine to form a
network of paths across the vast commons of the deep. Over these the
commercial, political, intellectual, or even purely migrant activities
of human life move from continent to continent. The distinctive value of
the sea is that it promotes many-sided relations as opposed to the
one-sided relation of the land. France on her eastern frontier comes
into contact with people of kindred stock, living under similar
conditions of climate and soil to her own; on her maritime border she is
open to intermittent intercourse with all continents and climes and
races of the world. To this sea border must be ascribed the share that
France has taken in the history of North and South America, the West
Indies, North and Equatorial Africa, India, China and the South Seas. So
we find the gr