ALEXANDRIA, VA., August 30, 1862-11 a.m.

His Excellency President LINCOLN:

Firing this morning is heard in direction of Centreville. I have sent out four trains. The first left at 4.30 a.m., the others following immediately: A wrecking train, to clear track; a construction train, to repair bridges; a train of forage, and one of bread and meat. A courier returning to General Pope last night was to convey the information that the trains would be at Sangster's Station soon after daylight with supplies. This point is 4 miles only from Centreville. I have directed that when the party arrives at Bull Run a detachment shall be sent forward on foot, with such tools as they can carry, to reach the engines and cars now cut off from communication at Catlett's, with instructions to work toward Bull Run, repair bridges and telegraph, call upon General Banks or any other officer for assistance and protection, and work along, opening communication with Bull Run. When this is done we can forward supplies by carrying them across Bull Run and reshipping. I have also sent wire, operator, and instruments with the expedition, and a force of 200 riflemen, with instructions to keep with the working party in the advance, and send out scouts and report everything.

The intelligence last evening was that Hooker and Pope were pushing the enemy toward the gap in the mountains through which they had advanced, and that McDowell and Sigel were heading them off. This morning the direction of the firing seems to be changing, and it is not impossible that the enemy's forces may be changing direction and trying to escape toward Fredericksburg, in which case my trains will be in great danger. I await intelligence with some anxiety, and will communicate anything of importance that I hear.

H. HAUPT.

ALEXANDRIA, VA., August 30, 1862-11.30 a.m.

Honorable ABRAHAM LINCOLN,

President of the United States:

Our operator has reached Manassas. Hears no firing of importance I have directed part of the 200 riflemen to go out as scouts, make observations, and report constantly. Two or three flashes just seen from Manassas in direction of Centreville.

Our expedition this morning appears to have been successful. We have re-established telegraph communication with Manassas, and if protected will soon have cars running; but the military authorities heretofore have never extended to us the protection that was necessary, and we have assumed the responsibility of going ahead without it. Our telegraph operators and railway employes are entitled to great credit. They have been advanced pioneers, occupying the post of danger; and the exploit of penetrating to Fairfax and bringing off the wounded, when they supposed 20,000 rebels were on their front and flanks, was one of the boldest performances I have heard of.

H. HAUPT.

ALEXANDRIA, VA., August 30, 1862.

The PRESIDENT and General HALLECK:

One of our men, who is just in, left Bristoe yesterday noon. Says our men had nearly finished repairing Kettle Run Bridge. A large num-