WASHINGTON, D. C., August 31, 1862.

Major-General POPE, Centreville, Va.:

I think a trustworthy officer should be sent to have the crossings and bridges of Bull Run and the Occoquan, above and below the railroad well guarded; this is important, to protect your line of supplies. Cannot Banks' corps, or a part of it, do this? We have sent you all we have, except raw troops, which are in the forts. Some more of Burnside's troops will be in to-morrow.

H. W. HALLECK,

General-in-Chief.

CIRCULAR.] HEADQUARTERS IN VIRGINIA,

Centreville, August 31, 1862.

Commanding officers of army corps will send back to Alexandria all wagons appertaining to their trains, except those absolutely necessary to haul subsistence stores and ammunition from Fairfax Court-House to this place for their respective corps.

This movement will be under charge of Colonel Clary, chief quartermaster, Army of Virginia.

By command of Major-General Pope:

GEO. D. RUGGLES,

Colonel and Chief of Staff.

HEADQUARTERS ARMY OF VIRGINIA,
Camp near Centreville, August 31, 18662-12 midnight.

Major-General McDOWELL:

GENERAL: General Pope directs that you immediately send a sufficient force to open the road from this point to Fairfax Court-House. The enemy made his appearance this afternoon on that road about 2 miles in rear of this point with several thousand cavalry and a battery of artillery.

I am, general, very respectfully, your obedient servant,

GEO. D. RUGGLES,

Colonel and Chief of Staff.

HDQRS. THIRD ARMY CORPS, ARMY OF VIRGINIA,
Camp near Centreville, August 31, 1862.

Brigadier General JOHN F. REYNOLDS, Commanding Division:

GENERAL: It not being the intention to make the position you now hold our field of battle, your division has been ordered in, with the exception of so much of is as may be necessary to constitute an outpost. If the nature of the ground be such that in withdrawing in face of the battery you report to have been established by the enemy on the crest opposite to you your column will be exposed to damage, you will withdraw before daylight to-morrow, taking your position in rear of Centreville, on the right of Ricketts' division.

The strength and composition of the outposts to be left on the crest of the hill will be left to your discretion. The Rhode Island cavalry will for the present be sent to that place, and it is thought that some