DEPARTMENT OF STATE, Washington, December 5, 1861.

Right Honorable Lord LYONS, &c.

MY LORD: I have the honor of replying to your lordship's note of the 3rd instant which relates to the cases of Rutson Maury and Matthew F. Maury.

These persons were arrested for having passed the lines of the army without permission of the authorities of the United States and in the act of preparing for again crossing the same lines without such authority, and in direct violation of well-known regulations established by the Government.

They were combined in business and that business was the carrying for hire of correspondence between insurgent citizens and their confederates in the United States and in Europe. On examination it was found that this correspondence was secreted with fraudulent design to escape exposure. Much of the correspondence was found to have for its objects, first, premeditated violation of the blockade; second, the treasonable supply of the insurgents with arms and munitions of war.

The illegal and treasonable partices in which they were engaged must be prevented. These persons are detained with that view.

I have inquired concerning the trunk of Matthew F. Maury and I learn that it is libeled with a view to the confiscation of the trunk itself and its contents by judicial proceeding in the State of Ohio.

I regret exceedingly that these young men have by such palpable acts of hostility to the United States rendered it necessary for the public safety that they be detained in custody. It is proper to say that the authorities in whose custody they are were early instructed to supply them with whatever of clothing and other things should be necessary for their comfort.

I have the honor to be, with high consideration, your lordship's obedient servant,

WILLIAM H. SEWARD.

DEPARTMENT OF STATE, Washington, December 5, 1861.

Right Honorable Lord LYONS, &c.

MY LORD: I have the honor to acknowledge the receipt of your communication of yesterday relative to the case of Mr. Rutson Maury, a British subject confined as a political prisoner in Fort Lafayette and to inform you in reply that I see nothing in it to alter the conclusion come to on the subject in my previous note to you of this date.

I avail myself of this opportunity to renew to your lordship the assurance of my high consideration.

WILLIAM H. SEWARD.

NEW YORK, December 5, 1861.

Honorable W. H. SEWARD, Secretary of State, &c.

SIR: I had the honor to address you on 30th of November in company with letters from sundry persons on the subject respecting the strange and unexplained detention of sundry letters belonging to Maury Bros. The inconvenience we are subjected to in consequence must be my excuse for again troubling you. On 2nd instant Superintendent Kennedy delivered some letters to us which he had received opn from your Department, telling us two were detained by you as apparently of a treasonable nature, which two I suppose must be from my brother, Rutson Maury, and from T. & H. Littledale & Co., or from the acting