Mr. Seward to Mr. Dayton.

No. 123.]

Sir: Your despatch of February 12 (No. 112) has been received. Surely all Europe ought to unite with us in establishing a telegraphic oceanic communication.

You very ably discuss the question of what is an effective blockade, while you suggest to me the desirableness of evidence to prove the efficiency of the one we have established.

We cannot know how many and what vessels succeed in running the blockade, and without this information statistics of the vessels prevented from doing so would be almost valueless. But the true test of the efficiency of the blockade will be found in its results. Cotton commands a price in Manchester, and in Rouen, and Lowell, four times greater than in New Orleans; salt, a price ten times higher in Charleston than in Liverpool. Gold is worth fifty per cent. more in Richmond than in New York. Notwithstanding the great outlay of the insurgents in Europe for arms, equipments, and clothing, in addition to their own boasted manufactures, the prisoners we take are wretchedly armed and clothed. Passengers from the insurgent States only escape into neutral States across overland barriers. Judged by this test of results, I am satisfied that there was never a more effective blockade. We are nevertheless very desirous to relieve the commerce of the world from our blockade, and to restore it to its natural and customary freedom. What do we wait for before doing this, but that the insurrection shall cease? What keeps the insurrection alive? Nothing, in my judgment, but the treatment of the insurgents as lawful belligerents by the maritime powers, utterly powerless as the former are to do any injury to foreign states. Their treatment as belligerents, while they are surrounded and hemmed within a small portion of the United States by the Union armies and navies, is believed to be without precedent as it is without necessity. Beside the commercial embarrassments which result from it, the United States are kept in continual and often unpleasant and anxious debate with maritime powers whose sympathies cannot but be with them, because their interests are identical with those of our own country.

You will have noticed our successful advance down the Mississippi and along its banks. Next week we shall ascertain the strength of the obstructions at Memphis. After passing that port the river will be entirely open to us to New Orleans. I suppose I hazard nothing of publicity here by informing [Page 321] you that General Butler, with an adequate land force, and Captain Porter, with a fleet, are already in motion to seize and hold New Orleans. The armies on the Potomac are also expected to try conclusions soon.

You will, I am sure, need no instructions to use this information in the way best calculated to free our unhappy domestic strife from its European elements of mischief. When that shall be done, all will be well.

While drawing this despatch to its close I learn that the insurgents have withdrawn from their front on the Potomac, above and below this city, and are breaking up their camps and retreating before our army towards Richmond. Thus ends the siege of Washington, and thus advances the cause of the Union.

I am, sir, your obedient servant,

WILLIAM H. SEWARD.

William L. Dayton, Esq, &c., &c., &c.