CIRCULAR.] CAMP NEAR FALMOUTH, VA.,

February 17, 1863.

The mail service between Washington and this army is placed under the supervision of the provost marshal-general, who will issue such instructions to give it efficiency, and at the same time prevent its being made the medium for conveying to the army unauthorized articles, as will in his judgment best attain the object in view.

The persons at present in charge of the mails at these headquarters may be continued in the duty, and three messengers are authorized for the mail duty at headquarters of each army corps and for the cavalry corps.

When detached divisions or brigades can be more conveniently supplied with mail-matter at other points than at corps headquarters, arrangements will be made by corps commanders, upon consultation with the provost marshal-general, to meet these cases, which must be limited, however, to instances where manifest delay and inconvenience would be occasioned by sending to corps headquarters.

By command of Major-General Hooker:

S. WILLIAMS,

Assistant Adjutant-General.

WINCHESTER, VA.,

February 17, 1863-5 a.m.

Brigadier General B. F. KELLEY,

Harper's Ferry, Va.:

DEAR SIR: I have reliable information that [William E.] Jones has been superseded by [A. J.] Grigsby, recently colonel of the Twenty-seventh Virginia, who has been re-enforced by Imboden. Their combined forces amount to 3,500 cavalry, 1,500 infantry, and three batteries, and that they have advanced a large portion of their force to Woodstock, and contemplate an early attack upon this place.

It is removed that they are about being re-enforced by Floyd with 6,000 infantry, and that D. H. Hill is coming through from Culpeper, by Berryville, will a force to cut me off.

Everything indicates, that this place is to be the first point of attack, and common reason, the nature and map of the country, and indications from the Secesh citizens, all point to this as the place of attack.

I can and will hold this place if I can have the whole of my command with me, and I insist that Colonel Washburn shall be ordered to join me at once.

This is borne by my aide-de-camp, Lieutenant Hammer, who will be the bearer of your answer.

I am, general, very truly, yours,

R. H. MILROY,

Brigadier-General.

HARPER'S FERRY, February 17, 1863.

Brigadier-General MILROY:

GENERAL: Your dispatch by Captain Otto received this morning at about 9 o'clock, and just at that time I received a dispatch from Colonel Washburn, advising me that he had information that the rebels were in Moorefield, about 2,000 infantry and 400 cavalry strong, and that his forage train, with the guard, had been captured yesterday by the rebel