When, however, the American government determined to send a special mission to England for the adjustment of differences between the two nations, the British habit of impressing on the high seas was stated as the foremost of the American grievances, and their plenipotentiaries were instructed to urge the abandonment of a practice “so disgraceful and injurious to their country, as the point most essential to its peace, honour, and tranquillity.” [Sidenote: Concessions made in the colonial trade.] [Sidenote: Blockades in the colonies, and of the French ports in the Channel.] As the second ground of complaint, the alleged violation of neutral rights by seizing and condemning their merchantmen though engaged in lawful commerce, involves a variety of important considerations, which were incessantly the subjects of dispute, it may be desirable to state the substance of the views of the American government and of English jurisconsults on so important a question. England had conceded to the Americans, in the previous war, permission to trade with the colonies of the enemy for articles intended for their own domestic consumption; and in case no market was found in the United States for articles imported with that intention, she had permitted them to re-export those articles to any part of the world not invested by her blockading squadrons. In 1804 certain ports of Martinique and Guadaloupe, French colonies, were declared to be in a state of blockade, and the siege of Curaçoa was also converted into a blockade. In August of the same year a rigorous blockade was declared to be established at the entrances of the ports of Fécamp, St. Valery, Caux, Dieppe, Treport, the Somme, Etaples, Boulogne, Calais, Gravelines, Dunkirk, Nieuport, and Ostend. Bonaparte at that moment was threatening England with invasion, and England was putting forth all her strength to repel the attempt and to circumvent his designs. America looked calmly on, and profited, as we have seen, by the struggle, pushing forward her pretensions and alleged grievances with the view of annoying as much as she could both belligerents, and especially Great Britain. England, as is well known, had constantly refused the Americans permission to trade directly between the colonies of the enemy and the mother-country, but had tolerated the indirect communication above mentioned, on the supposition that the goods so transmitted had been intended originally for American consumption, and would not have been re-exported, but for want of a market in the United States. [Sidenote: The dispute concerning the trade with the French colonies.]