WASHINGTON, September 18, 1863.

General S. A. MEREDITH, Commissioner for Exchanges:

SIR: Your communication of the 14th instant to Colonel Hoffman, inclosing the letter of Mr. Ould of the 11th, is before me.

For the purpose of guarding against a misunderstanding and an erroneous principle of action on the subject of declaring exchanges, you will inform Mr. Ould that the ex parte declaration of exchange, proposed in his communication to be made the next day (following the date of that communication), is deemed to be not only without authority from the cartel, but contrary to the usages of war.

The fifth article of the cartel (General Orders, Numbers 142, 1862) would have authorized Mr. Ould to discharge prisoners of the Federal forces, furnishing a list of them, and then to discharge an equal number of his own officers and men from parole. The cartel not only contemplates a mutual exchange of lists (article 5), but expressly declares (article 4) that no exchange is to be considered complete until the officer or soldier exchanged for has been actually restored to the lines to which he belongs.

In order to complete the arrangement declared by Mr. Ould it will be necessary for you to make a declaration of exchange of as many of our officers and men as have been delivered at City Point since the last declaration, provided the number does not exceed the number designated in Mr. Ould's declaration.

Then you can proceed further Mr. Ould for the discharge from parole of any excess which can be balanced either way by officers or soldiers actually on parole. Prisoners of war actually in our hands are not to be exchanged at the present time. You will please be careful not to jeopard this point. You can receive any officers or soldiers whom Mr. Ould may offer at City Point, and arrange with him for a mutual declaration of exchange for those of his officers and men already on parole in the South, grade for grade.

Colonel Hoffman's letter of the 5th ultimo will give you some suggestions about exchanges, but it will be necessary for you to be exceedingly guarded in framing your declaration to confine its application to rebel prisoners already paroled, and on no account, by any accident, to use language which can give the South a claim upon prisoners now in our actual possession; not but that these will be used for exchange at the proper time, but not while the North has, already delivered and on parole, more than enough to cover all deliveries made or to be made by the South.

Very respectfully, your obedient servant,

E. A. HITCHCOCK,

Major-General of Volunteers, Commissioner of Exchange.

HEADQUARTERS DEPARTMENT OF VIRGINIA,
Fort Monroe, September 18, 1863.

Colonel WILLIAM HOFFMAN,

Commissary-General of Prisoners, Washington, D. C.:

COLONEL: Your letter of the 16th instant received. I send you a remended declaration of exchange.

Very respectfully, your obedient servant,

S. A. MEREDITH,

Brigadier-General and Commissioner for Exchange.