to the proper sphere of army and navy in coast-defence. Passive
defences belong to the army; everything that moves in the water to the
navy, which has the prerogative of the offensive defence. If seamen
are used to garrison forts, they become part of the land forces, as
surely as troops, when embarked as part of the complement, become part
of the sea forces.
----

Here concludes the general discussion of the principal elements which
affect, favorably or unfavorably, the growth of sea power in nations.
The aim has been, first to consider those elements in their natural
tendency for or against, and then to illustrate by particular examples
and by the experience of the past. Such discussions, while undoubtedly
embracing a wider field, yet fall mainly within the province of
strategy, as distinguished from tactics. The considerations and
principles which enter into them belong to the unchangeable, or
unchanging, order of things, remaining the same, in cause and effect,
from age to age. They belong, as it were, to the Order of Nature, of
whose stability so much is heard in our day; whereas tactics, using as
its instruments the weapons made by man, shares in the change and
progress of the race from generation to generation. From time to time
the superstructure of tactics has to be altered or wholly torn down
but the old foundations of strategy so far remain, as though laid upon
a rock. There will next be examined the general history of Europe and
America, with particular reference to the effect exercised upon that
history, and upon the welfare of the people, by sea power in its broad
sense. From time to time, as occasion offers, the aim will be to
recall and reinforce the general teaching, already elicited, by
particular illustrations. The general tenor of the study will
therefore be strategical, in that broad definition of naval strategy