ALEXANDRIA DEPOT, VA., August 27, 1862-10.50 p.m.

Major-General McCLELLAN,

Washington:

The dispatch saying that the train which was sent for General Taylor was fired into, which I presume you have seen, I sent to General Franklin. Colonel Tyler was directed by General Marcy to inspect the forts and wait for further orders before he occupied them. He is now in camp near here. He reports that five instructed companies were left to garrison Forts Lyon, Worth, Ward, Blenker, Barnard, Richardson, and Scott. Some instructed recruits are left at each fort. What there is on the right of Fort Scott no one knows. Colonel Tyler thinks that the five companies above referred to should be concentrated at Fort Lyon, and he will try to take care of the rest. He would have been in forts now, but General Marcy told him to wait until he received permission from Washington for him to do so. I know your instruction was for him to take possession of the forts that required heavy artillerymen at once. There are many embrasures in each of these forts vacant, which could be filled by the guns in the siege train, if Tyler has orders to put them there. Mortars are necessary' could be put in if orders were given for it. I know it is your desire that this should be done and I told General Marcy so to-day, but as he objects to it until he could hear from Washington, I do not feel authorized to give the order. Colonel Tyler is here waiting for orders. Colonel Tyler can put his siege guns in position on short notice and replace many small and worthless guns now in the forts.

A. V. COLBURN,

Assistant Adjutant-General.

AUGUST 27, 1862-11.30 p.m.

Colonel A. V. COLBURN,

Assistant Adjutant-General, Alexandria:

Let Tyler move into the works early to-morrow morning, and use his siege guns and mortars to the best advantage he can.

GEO. B. McCLELLAN,

Major-General.

ALEXANDRIA, VA., August 27, 1862-12.20 a.m.

General HALLECK:

SIR: I have just received your dispatch addressed to Generals Smith, Sturgis, Slocum, or any general officer you can find, and, being senior officer here, will send forward all the infantry the railroad can furnish transportation for and as much artillery as can be moved to the point or points designated. Colonel Haupt has requested a force to protect the bridges at Bull Run, which furnish, unless otherwise instructed by you.

WINF'D S. HANCOCK,

Brigadier-General, Commanding Sixth Corps.