ALEXANDRIA, VA., August 27, 1862-12 m. (Received 1.30 p.m.)

Major General H. W. HALLECK,

General-in-Chief:

I have just learned, through General Woodbury, that it was stated in your office last night bank it was very strange that, with 20,000 men here, I did not prevent the raid upon Manassas. This induces me to ask whether your remark in your telegram to-day that there had been great neglect about Manassas was intended to apply to me? I cannot suppose it was, knowing, as you do, that I arrived here without information and with no instructions beyond pushing the loading of my troops. The bridge was burned before my arrival. I knew nothing of it till this morning. I ask as a matter of justice that you will prevent your staff from making statements which do such great injustice at a time when the most cordial co-operation is required.

GEO. B. McCLELLAN,

Major-General.

ALEXANDRIA, August 27, 1862-1.35 p.m. (Received 2.5p.m.)

General HALLECK:

I learn that Taylor's brigade, sent this morning to Bull Run Bridge, is either cut to pieces or captured.

That the force against them had many guns and about 5,000 infantry, receiving re-enforcements every minute; also that Gainesville is in possession of the enemy. Please send some cavalry out toward Dranesville, via Chain Bridge, to watch Lewinsville and Dranesville, and go as far as they can. If you will give me even one squadron of good cavalry here I will ascertain the state of the case. I think our policy now is to make these works perfectly safe and mobilize a couple of corps as soon as possible, but not to advance them until they can have their artillery and cavalry. I have sent for Colonel Tyler to place his artillerymen in the works.

Is Fort Marcy securely held?

GEO. B. McCLELLAN,

Major-General.

WASHINGTON, D. C., August 27, 1862.

Major-General McCLELLAN,

Alexandria, Va.:

No remark was made by me, or in my hearing, reflecting on you, in relation to Manassas. I did remark to General Woodbury, on receiving news of the capture of the train, that there must have been great neglect in permitting 500 of the enemy to make the raid, when we had some 20,000 men in that vicinity (not vicinity of Alexandria), and added that many of the forces sent to Pope could not have been very far off. It would have been perfect nonsense to have referred to you, when you had just arrived and knew nothing of the disposition of the troops. Indeed, I did not blame any particular person, but merely said there must have neglect somewhere. I think you must have misunderstood General Woodbury, for he could not possibly have drawn such an inference from anything I have said.

H. W. HALLECK,

General-in-Chief.