ion of the transport and food ships from raiders
like the _Wolfe_ and the _Moewe_.

The German High Command realised this as quickly as that of the Allies.
Their oversea commerce was strangled within a few days of the
Declaration of War with Great Britain, and their fleet was confined to
harbour, with the exception of occasional operations against Russia in
the Baltic. From the German standpoint the naval problem resolved itself
into one of how best to strike at the lines of communication of the
Allies, paying special attention, first, to the transport of troops,
and, second, to England's food supply. As they alone knew to what extent
they would violate the laws of war and of humanity, it became apparent
that the submarine and the mine were the only possible weapons which
could be used for this purpose in face of the superior fleets of the
Allies. But the number of these weapons was strictly limited compared
with the immense shipping resources at the command of the Western
Powers, so one submarine must do the work of many, and an effort was
made to accomplish this by a reign of sea terrorism and inhuman conduct
unparalleled in the history of the world. It opened with the sinking of
the _Lusitania_.

The Allies had secured and maintained the command of the sea, and _all
that it implies_, but to do this with the certainty of correct strategy
they had to dedicate almost their entire battle fleet to the purpose for
which battle fleets have always been intended--the checkmating or
annihilation of the opposing navy.

There came a second problem, however, one entirely new to sea warfare,
and unconsidered or provided against in its strategic and tactical
entirety because hitherto deemed too inhuman for modern war. This was
the ruthless use of armed submarines against unarmed passenger and
merchant ships, and the scattering broadcast over the seas, regardless
of the lives and property of neutrals, of thousands of explosive mines.

The type of ship constructed exclusively for open sea warfare against
surface adversaries was not the best answer to the submarine. The
blockading of the hostile surface fleet did not prevent, or even greatly
hinder, the free passage of submarine flotillas, and the building by
Germany of under-water mine-layers enabled fields of these weapons to be
laid anywhere within the carrier's radius of action.

In this way the second, or submarine, phase of the naval war opened, and
it was to supplement the