ermined objective, and a narrow sea where evasion by any
force of invasion strength is impossible. Napoleon's exploit was in fact
nothing more than the evasion of an open blockade which had no naval
defence beyond it. The vital importance of these things will appear as we
proceed and note the characteristics which marked every attempt to invade
England. From such attempts we of course exclude the various descents upon
Ireland, which, not being of invasion strength, fall into another class, to
be dealt with hereafter.

Since the expedient of forcing an invasion by the strength of a powerful
battleship escort has always been rejected as an inadmissible operation,
the invader has had no choice but to adopt a separate line for his army,
and operate with his fleet in such a way as may promise to prevent the
enemy controlling that line. That, in short, is the problem of invasion
over an uncommanded sea. In spite of an unbroken record of failure scored
at times with naval disaster, continental strategists from Parma to
Napoleon have clung obstinately to the belief that there is a solution
short of a complete fleet decision. They have tried every conceivable
expedient again and again. They have tried it by simple surprise evasion
and by evasion through diversion or dispersal of our naval defence. They
have tried it by seeking local control through a local naval success
prepared by surprise, or by attempting to entice our fleet away from home
waters to a sufficient extent to give them temporarily local superiority.
But the end has always been the same. Try as they would, they were faced
ultimately by one of two alternatives--they must either defeat our covering
battle-fleet in battle, or they must close their own battle-fleet on the
transports, and so set up the very situation which it was their main design
to avoid.

The truth is, that all attempts to invade England without command of the
sea have moved in a vicious circle, from which no escape was ever found. No
matter how ingenious or complex the enemy's design, a determined hold on
their army as the primary naval objective has always set up a process of
degradation which rendered the enterprise impracticable. Its stages are
distinct and recurrent, and may be expressed as it were diagrammatically as
follows:--

Two lines of operation having been decided on, the invading army is
gathered at a point as close as possible to the coast to be invaded; that
is, where the interveni