“The freedom of commerce, to which neutral states are entitled, does not extend to contraband of war; but, according to the principles laid down in the declaration of Paris of April 1856, it may now be said that ‘a ship at sea is part of the soil of the country to which it belongs,’ with the single exception implied in the right of a belligerent to search for contraband. What constitutes contraband is not precisely settled; the limits are not absolutely the same for all Powers, and variations occur in particular treaties; but, speaking generally, belligerents have a right to treat as contraband, and to capture, all munitions of war and other articles directly auxiliary to warlike purposes. The neutral carrier engages in a contraband trade when he conveys official despatches from a person in the service of the enemy to the enemy’s possessions; but it has been decided that it is not illegal for a neutral vessel to carry despatches from the enemy to his Ambassador or his Consul in a neutral country. The penalty of carrying contraband is confiscation of the illegal cargo, and sometimes condemnation of the ship itself. “The affair of the Trent, West Indian mail, gave rise to an important question of maritime law deeply affecting the rights of neutrals. In November 1861, Captain Wilkes, of the American war-steamer San Jacinto, after firing a roundshot and a shell, boarded the English mail-packet Trent, in Old Bahama Channel, on its passage from Havannah to Southampton, and carried off by force Messrs Mason and Slidell, two Commissioners from the Confederate States, who were taken on board as passengers bound for England. The Commissioners were conveyed to America, and committed to prison; but, after a formal requisition by Britain, declaring the capture to be illegal, they were surrendered by the Federal Government. “The seizure of the Commissioners was attempted to be justified by American writers on two grounds: 1st, That the Commissioners were contraband of war, and that in carrying them the Trent was liable to condemnation for having committed a breach of neutrality; 2d, That, at all events, Captain Wilkes was entitled to seize the Commissioners either as enemies or rebels. Both these propositions are plainly untenable.... “In an able despatch by the French. Government to the Cabinet of Washington, M. Thouvenel declared that the seizure of the Commissioners in a neutral ship, trading from a neutral port to a neutral port, was not only contrary to the law of nations, but a direct contravention of the principles which the United States had up to that time invariably avowed and acted upon. Russia, Austria, and Prussia officially intimated their concurrence in that opinion.