ossibilities. The old strategical conditions, so far as can be
seen, are unaltered except in so far as the reactions of modern material
make them tell in favour of defence rather than of attack.

If we desire to formulate the principles on which this conclusion rests we
shall find them in the two broad rules, firstly, that the vulnerability of
trade is in inverse ratio to its volume, and secondly, that facility of
attack means facility of defence. The latter, which was always true,
receives special emphasis from modern developments. Facility of attack
means the power of exercising control. For exercise of control we require
not only numbers, but also speed and endurance, qualities which can only be
obtained in two ways: it must be at the cost of armour and armament, or at
the cost of increased size. By increasing size we at once lose numbers. If
by sacrificing armament and armour we seek to maintain numbers and so
facilitate attack, we at the same time facilitate defence. Vessels of low
fighting power indeed cannot hope to operate in fertile areas without
support to overpower the defence. Every powerful unit detached for such
support sets free a unit on the other side, and when this process is once
begun, there is no halting-place. Supporting units to be effective must
multiply into squadrons, and sooner or later the inferior Power seeking to
substitute commerce destruction for the clash of squadrons will have
squadronal warfare thrust upon him, provided again the superior Power
adopts a reasonably sound system of defence. It was always so, and, so far
as it is possible to penetrate the mists which veil the future, it would
seem that with higher mobility and better means of communication the
squadronal stage must be reached long before any adequate percentage
impression can have been made by the sporadic action of commerce
destroyers. Ineffectual as such warfare has always been in the past, until
a general command has been established, its prospects in the future, judged
by the old established principles, are less promising than ever.

Finally, in approaching the problem of trade protection, and especially for
the actual determination of the force and distribution it requires, there
is a dominant limitation to be kept in mind. By no conceivable means is it
possible to give trade absolute protection. We cannot make an omelette
without breaking eggs. We cannot make war without losing ships. To aim at a
standard of naval st