e Englishmen mentions the yet more striking
coincidence, that in both cases the mastery of the sea rested with the
victor. The Roman control of the water forced Hannibal to that long,
perilous march through Gaul in which more than half his veteran troops
wasted away; it enabled the elder Scipio, while sending his army from
the Rhone on to Spain, to intercept Hannibal's communications, to
return in person and face the invader at the Trebia. Throughout the
war the legions passed by water, unmolested and unwearied, between
Spain, which was Hannibal's base, and Italy, while the issue of the
decisive battle of the Metaurus, hinging as it did upon the interior
position of the Roman armies with reference to the forces of Hasdrubal
and Hannibal, was ultimately due to the fact that the younger brother
could not bring his succoring reinforcements by sea, but only by the
land route through Gaul. Hence at the critical moment the two
Carthaginian armies were separated by the length of Italy, and one was
destroyed by the combined action of the Roman generals.

On the other hand, naval historians have troubled themselves little
about the connection between general history and their own particular
topic, limiting themselves generally to the duty of simple chroniclers
of naval occurrences. This is less true of the French than of the
English; the genius and training of the former people leading them to
more careful inquiry into the causes of particular results and the
mutual relation of events.

There is not, however, within the knowledge of the author any work
that professes the particular object here sought; namely, an estimate
of the effect of sea power upon the course of history and the
prosperity of nations. As other histories deal with the wars,
politics, social and economical conditions of countries, touching upon
maritime matters only incidentally and generally unsympathetically, so
the present work aims at putting maritime interests in the foreground,
without divorcing them, however, from their surroundings of cause and
effect in general history, but seeking to show how they modified the
latter, and were modified by them.

The period embraced is from 1660, when the sailing-ship era, with its
distinctive features, had fairly begun, to 1783, the end of the
American Revolution. While the thread of general history upon which
the successive maritime events is strung is intentionally slight, the
effort has been to present a clear a