eases her chances of
evasion.

From these and similar considerations it is obvious that the possibilities
of operations on the great trade-routes are much less extensive than they
were formerly, while to speak of cruisers "infesting" those routes is sheer
hyperbole. Under modern conditions it is scarcely more feasible than it
would be to keep up a permanent blockade of the British Islands. It would
require a flow of ships in such numbers as no country but our own can
contemplate possessing, and such as could not be maintained without having
first secured a very decided preponderance at sea. The loss of radius of
action therefore, though it does not increase the power of defence,
sensibly lessens that of attack by pelagic operations.

For the great increase in the powers of defence we must turn to the
extraordinary development in the means of distant communication. Under
former conditions it was possible for a cruising ship to remain for days
upon a fertile spot and make a number of captures before her presence was
known. But since most large merchantmen have been fitted with wireless
installations, she cannot now attack a single one of them without fear of
calling down upon her an adversary. Moreover, when she is once located,
every ship within wireless reach can be warned of her presence and avoid
her. She must widely and constantly shift her position, thereby still
further reducing her staying power. On the whole, then, it would appear
that in so far as modern developments affect the problem, they certainly
render pelagic operations far more difficult and uncertain than they used
to be. Upon the great routes the power of attack has been reduced and the
means of evasion has increased to such an extent as to demand entire
reconsideration of the defence of trade between terminal areas. The whole
basis of the old system would seem to be involved. That basis was the
convoy system, and it now becomes doubtful whether the additional security
which convoys afforded is sufficient to outweigh their economical drawbacks
and their liability to cause strategical disturbance.

Over and above the considerations already noticed, there are three others,
all of which favour the security of our trade by permitting a much more
extended choice of route. The first is, that steam vessels are not forced
by prevailing winds to keep to particular courses. The second is, that the
improvements in the art of navigation no longer render it so nec