to afford adequate defence against the smallest warship afloat, least
of all against torpedo craft. Hence, unless the sea to be traversed has
been cleared of the naval forces of the enemy beforehand, the invading
military force must be covered by a naval force sufficient to overcome
any naval force which the enemy is able to bring against it. If the
latter can bring a fleet--as he must be able to do if the invasion is
to be prevented--the covering fleet must be able to beat any fleet that
he can bring. That condition being satisfied, however, it is clear that
the covering fleet must be terribly hampered and handicapped in the
ensuing conflict by the presence of a huge and unwieldy assemblage of
unarmed transports filled with disarmed men, and by the consequent
necessity of defending it against the attack of those portions of the
enemy's naval force to which, albeit not suitable for engaging in the
principal conflict, the transports would offer an otherwise defenceless
prey. Hence the escorting fleet must be stronger than its adversary in a
far larger proportion than it need be if naval issues pure and simple
were alone at stake--so strong indeed that, if the transports were out
of the way, its victory might be taken as certain. But if that is so it
is manifest that the prospects of successful invasion would be
immeasurably improved by seeking to decide the naval issue first--as
Tourville very properly did in the Beachy Head campaign--and keeping the
transports in hand and in port until it had been decided in favour of
the intending invader. This is the eternal dilemma of invasion across a
sea of which the command has not previously been secured. If you are not
strong enough to dispose of the enemy's naval force you are certainly
not strong enough to escort an invading force--itself helpless
afloat--across the sea in his teeth. If you are strong enough to do this
you will certainly be wise to beat him first, because then there will be
nothing left to prevent the transit of your troops. In other words,
command of the sea, if not absolutely and in all cases indispensable to
a successful invasion, is at any rate the only certain way of ensuring
its success.

Naval history from first to last is full of illustrations of the
principles here expounded. I will examine one or two of them, and I must
take my illustrations mainly from the naval history of Britain, first,
because Britain, being an island, is the only country in Euro