Mr. Seward to Mr. Sanford.

Sir: I have the honor to acknowledge the receipt of your despatch of the 15th of September, No. 215, which mentions a probability that a special and extraordinary mission will be sent by the Belgian government to the so-called Imperial government in Mexico. I have also received your private note, which mentions that Mr. Blondeel von Cuelebroeck, now minister plenipotentiary here, will likely be appointed to fill that extraordinary mission.

This government can have no right to question such a proceeding by the Belgian government, but it is easy to perceive that if the representative of Belgium shall be sent to Mexico to recognize a foreign imperial revolutionary government there, while the United States remain in treaty relations with the native republican government still existing in Mexico, and if that representative should, immediately after performing that function, be returned to the United States to renew his mission here, the transaction would then be liable to popular misapprehension, which, even though it should not impair his usefulness, might at least render his residence less agreeable than it is to be desired.

You may verbally and unofficially suggest these considerations to Mr. Rogier for his reflection.

I am, sir, your obedient servant,

WILLIAM H. SEWARD.

Henry S. Sanford, Esq., &c., &c., &c., Brussels.