ROCKVILLE, MD., September 7, 1862.

General R. B. MARCY:

All quiet in front this morning. I would respectfully request that I may be re-enforced, in readiness to advance upon the communications of the enemy when it is deemed proper that I should do so.

E. V. SUMNER,

Major-General.

HEADQUARTERS ARMY OF THE POTOMAC,
Washington, September 7, 1862.

Major General S. P HEINTZELMAN,

Commanding Third Corps, Fort Lyon:

Major General FITZ JOHN PORTER,

Commanding Fifth Corps, Fort Corcoran:

Brigadier General J. P. SLOUGH, Alexandria:

General McClellan has been informed that the rebels intend making a raid to-night on Alexandria. Little reliance is placed on the information, but it is nevertheless suggested that it may by well, as a matter of precaution, to have your pickets, &c., more than usually on the alert.

By command:

S. WILLIAMS,

Assistant Adjutant-General.

SPECIAL ORDERS,

Numbers 4.

HEADQUARTERS,

Washington, September 7, 1862.

I. Brigadier General D. P. Woodbury is assigned to the command of all the forts beyond the Eastern Branch, north of the Potomac.

During the absence of the major-general commanding from Washington, the immediate command of the defenses of the capital is assigned to Major-General Banks, who, while exercising said command, will be relieved temporarily from the command of his corps.

II. Brigadier General S. D. Sturgis is temporarily relieved from duty with Porter's corps, and ordered to report to General Burnside.

* * * * * * * * * *

VIII. Colonel George D. Ruggles, additional aide-de-camp, having reported to these headquarters, in compliance with instructions from the General-in-Chief, is announced as attached to the staff of the general commanding, and will be obeyed and respected accordingly.

* * * * * * * * * *

By command of Major-General McClellan:

[S. WILLIAMS,]

Assistant Adjutant-General.

GENERAL ORDERS,

Numbers 1.

HDQRS. THIRD CORPS, ARMY OF VIRGINIA,
Leesborough, Md., September 7, 1862.

In conformity with Special Orders, Numbers 3, dated Headquarters Washington, September 6, 1862, the undersigned assumes command of the Third Corps of the Army of Virginia. Until further orders, the following-named officers are announced as members of the staff: Major Joseph Dickinson, assistant adjutant-general; Capts. William H. Lawrence, William L. Candler, and A. Moore, aides-de-camp; Lieutenant Colonel Fred.