[738] Recognised by article 6 of the Declaration of London.
Blockade, Outwards and Inwards.
§ 371. As a rule a blockade is declared for the purpose of preventing ingress as well as egress. But sometimes only ingress or only egress is prevented. In such cases one speaks of "Blockade inwards" and of "Blockade outwards" respectively. Thus the blockade of the mouth of the Danube declared by the Allies in 1854 during the Crimean War was a "blockade inwards," since the only purpose was to prevent supply reaching the Russian Army from the sea.[739]
[739] The Gerasimo (1857), 11 Moore, P.C. 88.
What Places can be Blockaded.
§ 372. In former times it was sometimes asserted that only ports, or even only fortified[740] ports, could be blockaded, but the practice of the States has always shown that single ports and portions of an enemy coast as well as the whole of the enemy coast may be blockaded. Thus during the American Civil War the whole of the coast of the Confederate States to the extent of about 2500 nautical miles was blockaded. And attention must be drawn to the fact, that such ports of a belligerent as are in the hands of the enemy may be the object of a blockade. Thus during the Franco-German War the French blockaded[741] their own ports of Rouen, Dieppe, and Fécamp, which were occupied by the Germans. Article 1 of the Declaration of London indirectly sanctions the practice of the States by enacting that "a blockade must not extend beyond the ports and coasts belonging to or occupied by the enemy."
[740] Napoleon I. maintained in his Berlin Decrees: "Le droit de blocus, d'après la raison et l'usage de tous les peuples policés, n'est applicable qu'aux places fortes."
[741] See Fauchille, Blocus, p. 161.
Blockade of International Rivers.
§ 373. It is a moot question whether the mouth of a so-called international river may be the object of a blockade, in case the riparian States are not all belligerents. Thus, when in 1854, during the Crimean War, the allied fleets of Great Britain and France blockaded the mouth of the Danube, Bavaria and Württemberg, which remained neutral, protested. When in 1870 the French blockaded the whole of the German coast of the North Sea, they exempted the mouth of the river Ems, because it runs partly through Holland. And when in 1863, during the blockade of the coast of the Confederate States, the Federal cruiser Vanderbilt captured the British vessel Peterhoff[742] destined for Matamaros, on the Mexican shore of the Rio Grande, the American Courts released the vessel on the ground that trade with Mexico, which was neutral, could not be prohibited.