FOREIGN OFFICE, [London,] December 6, 1861.

[Lord LYONS, &c., Washington.]

MY LORD: Count Flahault read to me to-day a dispatch addressed to him by M. Thouvenel covering one from M. Thouvenel to M. Mercier. * In this letter M. Thouvenel reviews with great ability the question of the captures on board the Trent.

He begins by saying that the transaction appeared to be so much at variance with the ordinary rules of international law that the impression on the public opinion in France was that the commander of the San Jacinto could alone be responsible for it. If, however, the Cabinet of Washington should be disposed to approve the conduct of that officer it could do so only on one or other of the grounds of Mr. Mason and Mr. Slidell being enemies or being rebels; and in either case it would depart greatly from those principles on which hitherto France and the United States have been agreed. As regards the former case, that, namely, of the two gentlemen being considered enemies, the United States in their treaties with France had recognized that the freedom of the flag extended to all persons except military or naval officers actually in the service of the enemy found under it; and according to this principle Mr. Mason and Mr. Slidell were free under the neutral flag of England. Neither could those gentlemen be deemed contraband of war; for although no general rule as to the contraband was universally admmitted the character of persons liable to be considered as contraband was at all events clearly defined, and Mr. Mason and Mr. Slidell did not bear that character.

Then again as regards the allegation that they were bearers of dispatches of the enemy the conduct of the U. S. cruiser was wholly unjustifiable. The Trent was not destined for a port of either of the belligerents; she was on her voyage to a neutral country with cargo and passengers which she had embarked in a neutral country; and if it were assumed that under such circumstances the neutral flag did not protect passengers and cargo the immunity of that flag would be an idle word, and restrictions wholly inadmissible according to the principles would thereby be imposed on the freedom of commerce and navigation. As regards the latter case, that, namely, of Mr. Mason and Mr. Slidell being considered rebels, M. Thouvenel observes that neither in this case was the conduct of the commander of that San Jacinto justifiable for he will have diregarded the received principle that a vessel forms part of the territory of the State whose flag it bears and is therefore exempt from foreign jurisdiction.

Under these circumstances M. Thouvenel considers it impossible that the Cabinet of Washington should approve the conduct of the commander of the San Jacinto, and accordingly in his oopinion it cannot hesitate as to the decision which it should adopt. It should asquisce in the demands which Lord Lyons was instructed to make for the immediate liberation of the two gentlement and for suchexplanation as may efface the offense done to the British flag. It is impossible to conceive what object or interest it could have in provoking by a different course a rapture wilth Great Britain. Such a rupture France would consider not only as lamentable with reference to the difficulties with which the Cabinet of Washington has already to contend but also as establishing a precedent calculated seriously to disquiet all powers who are standing aloof fro the conflict now going on; and M. Thouvenel considers that

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*See Thouvenel to Mercier, December 3, p. 1116.

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71 R R-SERIES II, VOL II