tation. In 1840 the first Cunard liner, of 740
horse-power with a speed of 8.5 knots per hour, was launched. In 1907,
when the Lusitania was built, ocean-going vessels had attained a speed
of 25 knots an hour and were drawn by engines of 70,000 horse-power.

It is difficult to estimate the economic changes which have been brought
about by the changes in ocean transportation represented by these
figures. It is still less possible to predict the political effects of
the steadily increasing mobility of the peoples of the earth. At the
present time this mobility has already reached a point at which it is
often easier and cheaper to transport the world's population to the
source of raw materials than to carry the world's manufactures to the
established seats of population.

With the progressive rapidity, ease, and security of transportation, and
the increase in communication, there follows an increasing detachment of
the population from the soil and a concurrent concentration in great
cities. These cities in time become the centers of vast numbers of
uprooted individuals, casual and seasonal laborers, tenement and
apartment-house dwellers, sophisticated and emancipated urbanites, who
are bound together neither by local attachment nor by ties of family,
clan, religion, or nationality. Under such conditions it is reasonable
to expect that the same economic motive which leads every trader to sell
in the highest market and to buy in the lowest will steadily increase
and intensify the tendency, which has already reached enormous
proportions of the population in overcrowded regions with diminished
resources, to seek their fortunes, either permanently or temporarily, in
the new countries of undeveloped resources.

Already the extension of commerce and the increase of immigration have
brought about an international and inter-racial situation that has
strained the inherited political order of the United States. It is this
same expansive movement of population and of commerce, together with the
racial and national rivalries that have sprung from them, which first
destroyed the traditional balance of power in Europe and then broke up
the scheme of international control which rested on it. Whatever may
have been the immediate causes of the world-war, the more remote sources
of the conflict must undoubtedly be sought in the great cosmic forces
which have broken down the barriers which formerly separated the races
and nationalities of t