efficiency.

9. Torpedo craft are of little or no use for commerce destruction except
in certain well-defined areas where special measures can be taken for
checking their depredations.

Of course all this depends on the one fundamental assumption that the
commerce to be defended belongs to a Power which can, and does, command
the sea. On no other condition can maritime commerce be defended at
all.

CHAPTER VIII

THE DIFFERENTIATION OF NAVAL FORCE

A warship, considered in the abstract, may be defined as a vessel
employed, and generally constructed, for the purpose of conveying across
the seas to the place of conflict, the weapons that are to be used in
conflict, the men who are to use them, and all such stores, whether of
food or other supplies, as will give to the vessel as large a measure of
enduring mobility as is compatible with her displacement. If we confine
our attention to the period posterior to the employment of the gun on
shipboard as the principal weapon of offence, and if we regard the
torpedo as a particular kind of projectile, and the tube from which it
is discharged as a particular kind of gun, we may condense this
definition into the modern formula that a warship is a floating
gun-carriage. With the methods and implements of sea warfare anterior to
the introduction of the gun we need not concern ourselves. They belong
to the archaeology of the subject. It suffices to point out that in all
periods of naval warfare the nature of the principal weapon employed,
and to some extent that of the motive power available, have not only
governed the structure of the ship and determined the practicable limit
of its displacement, but have also exercised a dominant influence over
the ordering of fleets and their disposition in action. Sea tactics have
never been more elaborate than they were in the last days of the galley
period which came to an end with the Battle of Lepanto in 1571, less
than a score of years before the defeat of the Armada in 1588. But the
substitution of sails for oars as the motive power of the warship and
the more general employment of the gun as the principal weapon of
offence necessarily entailed radical changes in the tactical methods
which had been slowly evolved during the galley period. At first all was
confusion and a sea-fight was reduced for a time to a very disorderly
and tumultuous affair. "We went down in no order," wrote an officer who
was present at Trafalgar, "but ev