WASHINGTON, September 28, 1861.

Honorable WILLIAM H. SEWARD, Secretary of State.

SIR: Mr. Robert Mure, of Charleston, S. C., now confined in fort Lafayette expresses his ignorance of the contents of the letters in his possession when he was arrested and states himself to be innocent of any complicity with treason to the United States Government. In his behalf I would respectfully request an opportunity for him to give his deposition under oath upon the subject, to be added to such other evidence as may be obtatined bearing upon his case, to be made the basies of an application to your Department for his release from imprisonment. To obtain the deposition of Mr. Mure I would respectfully ask either that a pass may be given to myself accompanied by some person competent to administer an oath or that some Government officer or other person may be appointed by the Department to examine Mr. Mure and reduce his deposition to writing.

Very respectfully, your obedient servant,

JAMES THOMSON.

69 Wall Street, New York.

FORT LAFAYETTE, October 2, 1861.

MY DEAR SIR: The receipt of your note of 27th ultimo conveying a letter from Mr. Middleton was truly cheering and most gratefully appreciated by me. Poor fellow, he knows how innocent I am of any treason. I am glad you read his letter for it speaks for itself. Hearing Mr. Thomson has returned from Washington without reaching any satisfaction in my case is disappointing, but I have reconciled myself to whatever Mr. Seward has in store for me, satisfied of my own innocence and that the Government is acting oppressively and wrongfully with me. I inwardly feel this which nerves me to stand up against my present rials, hopeful that brigher and happier days will soon be restored to the country. I can never repay you for the unitiring interest you have taken in my misfortune. I hope to see the end of all this and prove to you and others my innocence of the course the Government is pursuhey require me to take an oath before I can get out of here, without guaranteeing my personal security in South Carolina, or the safety of my property there. Now as matters stand I hope soon to have protection worth having for I intend to return to my own dar native land where I can secure myself by returning to my first allegiance, the hom eof my birth.

I have a letter from my son Robert. Poor lad, he is distressed about me but hopes I will soon be in Scotland. I observe the Liverpool cotton market is advancing. As I have no late letters, I do not know ho my interest there stands but presume my friends have sold out some time ago which may be unfortunate, but I wait advices. When does your father return home? I suppose he is only on a business trip and may soon be home again. There have been 136 prisoners in this fort, but are now reduced to 106. We are too crowded for comfort, but I rejoice to say the most of the inmates are gentlemen and deserve another fate than mere confinement on suspicion. The President says no one is in here but on satisfactory evidence of treason. Alas, I fee this is not so, but we must all yield to the powers that be, be they for good or evil.