I. There is no rule of law more established than this; that the Breach of a Blockade subjects the property so employed to confiscation.  Every man knows it; the subjects of all states know it.

A lawful maritime blockade requires the actual presence of a sufficient force stationed at the entrance of the port, sufficiently near to prevent communication.

The blockade is to be considered legally existing, although the winds may occasionally blow off the blockading squadron.  It is an accidental change which must take place in every blockade; but the blockade is not therefore suspended.

This axiom is laid down in all books of authority; and the law considers an attempt to take advantage of such an accidental removal as an attempt to break the blockade, and a mere fraud.[185]

When a blockading squadron is driven off by a superior force, the blockade is effectually raised, and it must be renewed by fresh notification, before foreign nations can be affected by an obligation to observe it as a blockade.  The mere appearance of another squadron will not renew it, but it must be restored by the measures required for the original imposition of a blockade.[186]

[Sidenote:  Second Rule of Blockade.]

It is necessary that the evidence of a blockade should be clear and decisive.  A blockade may exist without a public declaration; although a declaration, unsupported by fact, will not be sufficient to establish it.  In the War of 1798, the West India Islands were declared under blockade by Admiral Jervis; but the Lords of the Supreme Court held, that as the fact did not support the declaration, a blockade could not be deemed legally to exist.  But the fact, on the contrary, duly notified on the spot, is of itself sufficient; for public notifications between governments are meant for the information of individuals; but if the individual is personally informed, that purpose is better obtained than by a public declaration.[187]

Where the vessel sails from a country lying near enough to the blockaded port to have constant information of the blockade, no notice is necessary of its continuance or relaxation; but when the country is at a distance beyond constant information, they may lawfully send their vessels on conjecture that the blockade is broken up, after it has existed a long time.[188] And this is important, as it must be remembered that even the intention to evade blockade is a fraudulent breach of it, and sailing towards the port is an overt act of that intent.[189]

There are two kinds of Blockade. 1.  Simple Blockade, i.e. Blockade in Fact; and 2nd., Blockade in Fact, accompanied by a Notification.  The first expires by the breaking up intentionally of the blockading squadron.  The second, prima facie, does not expire until the repeal of the notification, but it is the duty of the belligerent country directly the blockade ceases, de facto, to revoke its proclamation.  And it would appear that a notified blockade would only expire, in fact, after some unnecessary and long neglect to publish this revocation; otherwise neutral nations are bound until such publication.[190]