regions, led to wars. On the other hand, wars arising from other
causes have been greatly modified in their conduct and issue by the
control of the sea. Therefore the history of sea power, while
embracing in its broad sweep all that tends to make a people great
upon the sea or by the sea, is largely a military history; and it is
in this aspect that it will be mainly, though not exclusively,
regarded in the following pages.

A study of the military history of the past, such as this, is enjoined
by great military leaders as essential to correct ideas and to the
skilful conduct of war in the future. Napoleon names among the
campaigns to be studied by the aspiring soldier, those of Alexander,
Hannibal, and Caesar, to whom gunpowder was unknown; and there is a
substantial agreement among professional writers that, while many of
the conditions of war vary from age to age with the progress of
weapons, there are certain teachings in the school of history which
remain constant, and being, therefore, of universal application, can
be elevated to the rank of general principles. For the same reason the
study of the sea history of the past will be found instructive, by its
illustration of the general principles of maritime war,
notwithstanding the great changes that have been brought about in
naval weapons by the scientific advances of the past half century, and
by the introduction of steam as the motive power.

It is doubly necessary thus to study critically the history and
experience of naval warfare in the days of sailing-ships, because
while these will be found to afford lessons of present application and
value, steam navies have as yet made no history which can be quoted as
decisive in its teaching. Of the one we have much experimental
knowledge; of the other, practically none. Hence theories about the