e, 1917.

CHAPTER VI

OPENING THE OCEAN ROUTES

1. PORTUGAL AND THE NEW ROUTE TO INDIA

From the days of the Phoenicians to the close of the 15th century,
all trade between Europe and Asia crossed the land barrier east of
the Mediterranean. Delivered by Mohammedan vessels at the head of
the Persian Gulf or the ports of the Red Sea, merchandise followed
thence the caravan routes across Arabia or Egypt to the Mediterranean,
quadrupling in value in the transit. Intercourse between East and
West, active under the Romans, was again stimulated by the crusades
and by Venetian traders, until in the 14th and the 15th centuries
the dyes, spices, perfumes, cottons, muslins, silks, and jewels
of the Orient were in demand throughout the western world. This
assurance of a ready market and large profits, combined with the
capture of Constantinople by the Turks (1453), their piratical
attacks in the Mediterranean which continued unchecked until Lepanto,
and their final barring of all trade routes through the Levant,
revived among nations of western Europe the old legends of all-water
routes to Asia, either around Africa or directly westward across
the unknown sea.

With the opening of ocean routes and the discovery of America,
a rivalry in world trade and colonial expansion set in which has
continued increasingly down to the present time, forming a dominant
element in the foreign policies of maritime nations and a primary
motive for the possession and use of navies. The development of
overseas trade, involving the factors of merchant shipping, navies,
and control of the seas, is thus an integral part of the history
of sea power. The great voyages of discovery are also not to be
disregarded, supplying as they did the basis for colonial claims,
and illustrating at the same time the progress of nautical science
and geographical knowledge.

[Illustration: CROSS-STAFF]

The art of navigation, though still crude, had by the 15th century
so advanced that the sailor was no longer compelled to skirt the
shore, with only rare ventures across open stretches of sea. The
use of the compass, originating in China, had been learned from the
Arabs by the crusaders, and is first mentioned in Europe towards
the close of the 12th century. An Italian in England, describing a
visit to the philosopher Roger Bacon in 1258, writes as follows:
"Among other things he showed me an ugly black stone called a magnet
... upon which, if a needle be ru