HEADQUARTERS ARMY OF THE POTOMAC,
August 29, 1862 - 12 m. (Received 12.8 p. m.)

Major General H. W. HALLECK, General-in-Chief:

Your telegram received. Do you wish the movement of Franklin's corps to continue? He is without reserve ammunition and without transportation.

GEO. B. McCLELLAN,

Major-General.

HEADQUARTERS ARMY OF THE POTOMAC,
Alexandria, VA., August 29, 1862 - 12 m.

(Received 12.50 p. m.)

Major-General HALLECK, General-in-Chief:

Have ordered most of Twelfth Pennsylvania Cavalry to report to General Barnard for scouting duty toward Rockville, Poolesville, &c. If you apprehend a raid of cavalry on your side of river I had better send a brigade or two of Sumner's to near Tennallytown, where, with two or three old regiments in forts Allen and Marcy, they can watch both Chain Bridge and Tennallytown. Would it meet your views to post the rest of Summer's corps between Arligton and Fort Corcoran, where they can either support Cox, Franklin, or Chain Bridge, and even Tennallytown. Franklin has only between 10,000 and 11,000 ready for duty. How far do you wish this force to advance?

GEO. B. McCLELLAN,

Major-General, U. S. Army.

WASHINGTON, D. C., August 29, 1862 - 3 p.m.

Major-General McCLELLAN, Alexandria, Va.:

Your proposed disposition of Sumner's corps seems to me judicious. Of course I have no time to examine into details. The present danger is a raid upon Washington in the night-time. Dispose of all troops as you deem best. I want Franklin's corps to go far enough to find out something about the enemy. Perhaps he may get such information at Annandale as to prevent his going farther; otherwise he will push on toward Fairfax. try to get something form direction of Manassas, either by telegram or through Franklin's scouts. Our people must move more actively and find out where the enemy is. I am tired of guesses.

H. W. HALLECK,

General-in-Chief.

WASHINGTON, D. C., August 29, 1862.

Major-General McCLELLAN, Alexandria, Va.:

I think you had better place Sumner's corps at it arrives near the fortifications, and particularly at the Chain Bridge. The principal thing to be feared now is a cavalry raid into this city, especially in the night-time. Use Cox's and Tyler's brigades and the new troops for the same object of you need them.

Porter writes to Burnside from Bristoe, 9.30 a. m. yesterday, that Pope's forces were then moving on Manassas and that Burnside would soon hear of them by way of Alexandria.