Second Brigade of Hooker's division, Third Corps, and will report to Brigadier General D. N. Couch, commanding division, Fourth Corps, for the temporary command of Graham's brigade.

VI. Brigadier General H. W. Wessels, when relieved by Brigadier-General Abercrombie, will report to Brigadier General Silas Casey for the command of the brigade of this division lately commanded by Brigadier General William H. Keim.

* * * * * * * * *

By command of Major-General McClellan:

S. WILLIAMS,

Assistant Adjutant-General.

HEADQUARTERS ARMY OF THE POTOMAC,
Camp Cold Harbor, May 25, 1862 - 10.30 p. m.

General P. ST. G. COOKE,

Commanding Cavalry:

GENERAL: It has been reported to the commanding general this evening that a Dr. Pollock, living at or near Hanover Court-House, was heard to say that a force of 17,000 men would be at Hanover Court-House to-morrow -- rebel troops. The general desires you to send out one of your regiments along the road leading from your present position crossing the Totopotomoy and Crump's Creeks, in the direction of Hanover Court-House, and direct the officer in command to examine carefully all the roads leading into the road he travels; to examine all white and colored persons he can find, and endeavor to gain information regarding the movements of the enemy.

Please direct him to push forward his reconnaissance, feeling his way carefully, and keeping out scouts and flankers when he gets into a locality where he can be surprised, and go as far toward Hanover Court-House as he can with safety.

Colonels Warren and Tyler, with Rush's Lancers, are now at the Old Church, and have to-day thrown forward reconnoitering parties toward the Court House. They are on the right of the road that your command will march, and your officers should be informed that they will be likely to meet with some of these troops.

Rush's Lancers can readily be distinguished. Should your party meet with any persons who can give important information they will be sent back at once to these headquarters.

Your men should go light, well provided with cartridges, starting early in the morning, and they will probably be able to return the same night.

The facts regarding the report alluded to should be thoroughly investigated before the party returns.

Please direct the officer in command to gain all the information on his power about the movements of rebel troops along the Virginia Central Railroad during the past week.

Very, respectfully,

R. B. MARCY,

Chief of Staff.

GENERAL ORDERS,
HDQRS. ARMY OF THE POTOMAC,

No. 128. Camp near Cold Harbor, Va., May 25, 1862.

I. Upon advancing beyond the Chickahominy the troops will go prepared for battle at a moment's notice, and will be entirely unencumbered.