and the still longer and more
mysterious passage through the ancient oases of Turkestan, now buried in
sand, along which, as recent discoveries have shown us, Greece and
China, Christianity and Buddhism, exchanged their arts and ideas and
products. Then he would tell of the great age of maritime discovery, of
the merchant-adventurers and buccaneers, of their gradual transformation
into trading companies, in the East and in the West, from companies to
settlements, from settlements to colonies. Then perhaps he would close
by casting a glimpse at the latest human migration of all, that which
takes place or took place up to 1914, at the rate of a million a year
from the Old World into the United States. He would take the reader to
Ellis Island in New York harbour, where the immigrants emerge from the
steerage to face the ordeal of the Immigration Officer. He would show
how the same causes, hunger, fear, persecution, restlessness, ambition,
love of liberty, which set the great westward procession in motion in
the early days of tribal migration, are still alive and at work to-day
among the populations of Eastern Europe. He would look into their minds
and read the story of the generations of their nameless fore-runners;
and he would ask himself whether rulers and statesmen have done all that
they might to make the world a home for all its children, for the poor
as for the rich, for the Jew as for the Gentile, for the yellow and
dark-skinned as for the white.

Let us dwell for a moment more closely on one phase of this record of
the conquest of distance. The crucial feature in that struggle was the
conquest of the sea. The sea-surface of the world is far greater than
its land-surface, and the sea, once subdued, is a far easier and more
natural means of transport and communication. For the sea, the
uncultivable sea, as Homer calls it, is itself a road, whereas on earth,
whether it be mountain or desert or field, roads have first painfully to
be made. Man's definitive conquest of the sea dates from the middle of
the fifteenth century when, by improvements in the art of sailing and by
the extended use of the mariner's compass, it first became possible to
undertake long voyages with assurance. These discoveries are associated
with the name of Prince Henry of Portugal, whose life-long ambition it
was, to quote the words engraved on his monument at the southern
extremity of Portugal, 'to lay open the regions of West Africa across
th