ting the ports of departure with those of arrival. Accordingly the
sporadic attack on commerce by isolated warships cruising at large
within the limits of trade routes, which might be hundreds of miles in
width, was often productive of very appreciable results. There were few
blank coverts on the seas to be drawn. Nowadays a steamer can always
take the most direct course to her destination. As a consequence, trade
routes have now been narrowed down to what may more fittingly be called
lines of communication, and these lines possess the true characteristic
of all lines, namely, that they have practically no breadth. Thus the
areas bounded by these lines are nowadays all blank coverts. Any one who
happens to cross the Atlantic, as I have crossed it more than once, by
one of the less frequented routes, will know that the number of vessels
sighted in a voyage quite as long as any warship could take without
coaling may often be counted on the fingers of one hand. Another
characteristic of these lines is that though their points of departure
and destination are fixed, yet the lines joining these points may be
varied if necessary to such an extent that any warship hovering about
their ordinary direction would be thrown entirely off the scent. On the
other hand their ports of departure and destination being fixed, the
lines of communication must inevitably converge as they approach these
points. There are other points also more in the open at which several
lines of communication may intersect. At these "terminal and focal
points," as Mr Corbett has aptly called them, the belligerent, being by
hypothesis inferior to his adversary, must needs endeavour to
concentrate his attack on his enemy's commerce, because at any other
points the game would not be worth the candle. But it is precisely at
these points that the superior adversary will concentrate his defence,
and being superior, will take care to do so in force sufficient for the
purpose. So far as the remaining portions of the lines of communication
need any direct defence at all this can be afforded, if and when
necessary, by collecting the merchant ships about to traverse them into
convoys and giving them an escort sufficiently powerful to deal
effectually with attacks which from the nature of the case can only be
sporadic and intermittent. Be it remembered that the last thing a
warship bent on commerce destruction wants is to encounter an enemy in
superior or even in equal fo