other, it was also usually called
blockade, and Nelson's protest against the consequent confusion of thought
is well known. "It is not my intention," he said, "to close-watch Toulon";
and again, "My system is the very contrary of blockading. Every opportunity
has been offered the enemy to put to sea." It is desirable, therefore, to
adopt terms to distinguish the two forms. "Close" and "open" express the
antithesis suggested by Nelson's letter, and the two terms serve well
enough to mark the characteristic feature of each operation. Close
blockade, it is true, as formerly conceived, is generally regarded as no
longer practicable; but the antithetical ideas, which the two forms of
blockade connote, can never be eliminated from strategical consideration.
It must always be with the relations of these two forms, whatever shape
they may take in future, that the strategy of naval blockade is chiefly
concerned.

With regard to commercial blockade, in strict analysis it should be
eliminated from an inquiry that concerns methods of securing command and
postponed to that section of exercising command which deals with the attack
and defence of trade. It is, however, necessary to treat certain of its
aspects in conjunction with naval blockade for two reasons: one, that as a
rule naval blockade is indissolubly united to a subordinate commercial
blockade; and the other, that the commercial form, though its immediate
object is the exercise of control, has almost invariably an ulterior object
which is concerned with securing control; that is to say, while its
immediate object was to keep the enemy's commercial ports closed, its
ulterior object was to force his fleet to sea.

Commercial blockade, therefore, has an intimate relation with naval
blockade in its open form. We adopt that form when we wish his fleet to put
to sea, and commercial blockade is usually the most effective means we have
of forcing upon him the movement we leave him free to attempt. By closing
his commercial ports we exercise the highest power of injuring him which
the command of the sea can give us. We choke the flow of his national
activity afloat in the same way that military occupation of his territory
chokes it ashore. He must, therefore, either tamely submit to the worst
which a naval defeat can inflict upon him, or he must fight to release
himself. He may see fit to choose the one course or the other, but in any
case we can do no more by naval means alone to