In my opinion, this cavalry, if the Army of the Potomac contemplates no immediate movement, should either be stationed nearer to the Orange and Alexandria Railroad, or be employed in again attacking and breaking up the enemy's cavalry. It is rumored that Stuard and Lee are collecting a cavalry force at Culpeper. If so, it is probably for a raid upon Alexandria or into the Valley of the Shennadoah, which the cavalry of the Army of the Potomac should be prepared to prevent.

Since writing the foregoing, I learn verbally from General Butterfield that two divisions of the Cavalry Corps are stationed near the Orange and Alexandria Railroad; that two regiments have been sent to clean out the country between the Rappahannock and the Occoquan, and that two other regiments have been sent for the same purpose down the neck of land between the Potomac and Rappahannock.

If a mere cavalry raid should be made upon Alexandria, the only serious apprehensions would be for our stores at that place, while, on the other hand, the enemy's retreat ought to be cut off by the cavalry of General Stahel and that of the Army of the Potomac. If the enemy should attack in large force, we must rely for assistance mainly upon the army under General Hooker.

The efficiency of the defenses south of the Potomac would be greater if there was a more experienced officer in command of the forts and artillery. I therefore respectfully renew my recommendation that Colonel De Russy be made a brigadier-general of volunteers, in order that he may be assigned to that command.

In regard to the Army of the Potomac, I must respectfully refer you to my letter of the 18th. I have not now, nor have had since General Hooker assumed the command, any information in regard to its intended movements other than that which I have received from the President, to whom General Hooker reports directly.

Very respectfully, your obedient servant,

H. W. HALLECK,

General-in-Chief.

[Indorsement.]

MAY 24, 1863.

Respectfully referred to the President for his orders. The opinion that the large cavalry forces of the Army of the Potomac should be so disposed as to afford protection against the enemy's cavalry raids upon our military depots and exposed points is concurred in by the general commanding the department, Major-General Heintzelman, and the Quartermaster-General, who, under my direction, has just made a personal examination as to the defenses of our depots at Alexandria. As General Halleck, for reasons stated, does not deem himself authorized to give orders to General Hooker, it is submitted to the President whether the circumstances do not require him to give such directions as upon consideration of the within report may appear to be necessary.

EDWIN M. STANTON,

Secretary of War.

CAMP NEAR FALMOUTH, VA.,

May 23, 1863.

Commanding Officer, Cavalry Corps:

I am directed by the major-general commanding to acknowledge your communication of the 22nd instant, relating to the positions to which