To create a diversion in your favor a powerful expedition has been organized and will be in full movement to-morrow, the 28th instant, to operate toward the left flank of the enemy in the direction of Charlottesville, which will be extended to the railroad bridge across the Rivanna, in the vicinity of that town, if practicable, and the bridge destroyed. This operation will be followed up by other movements of troops, and it is expected by these means so to distract the attention of the enemy that every chance for the success of your expedition will be secured that it is practicable to provide for here.

If you succeed in liberating the prisoners you will conduct them within our lines at Williamsburg, and then, if, if your judgment, upon the facts known to you as to the disposition of the forces of the enemy and the state of the weather, it be practicable you will return to your former position in this army by way of the crossings of the Rappahannock or Rapidan. The movements intended to create a diversion in your favor will be in full operation on the 28th and 29th instant, and will extend beyond that time. You will therefore commence your movement on the night of the 28th instant.

I am directed by the major-general commanding to say that no detailed instructions are given you, since the plan of your operations has been proposed by yourself, with the sanction of the President and the Secretary of War, and has been so far adopted by him that he considers success possible with secrecy, good management, and the utmost expedition.

A. A. HUMPHREYS,

Major-General, Chief of Staff.

[Inclosure Numbers 3.]

Numerical list of casualties in the Cavalry Corps during expedition of General Kilpatrick to Richmond.

Killed. Wounded.

Command. Officers Men. Officers Men

First

Division:

3rd -- 1 -- --

Indiana

Cavalry

4th New -- -- -- --

York

Cavalry

17th -- -- -- 1

Pennsylvan

ia Cavalry

Second

Division:

1st Maine -- 1 -- 2

Cavalry

16th -- -- -- --

Pennsylvan

ia

4th -- -- -- --

Pennsylvan

ia Cavalry

Third

Division:

2nd New -- 3 -- --

York

Cavalry

5th New -- -- -- 2

York

Cavalry

18th -- -- -- 1

Pennsylvan

ia Cavalry

5th -- -- -- 2

Michigan

Cavalry

6th -- -- -- --

Michigan

Cavalry

7th -- -- -- --

Michigan

Cavalry

1st -- 1 -- 4

Vermont

Cavalry

Total -- 6 -- 12

Missing

Command. Officers Men Aggregate

First Division:

3rd Indiana -- 2 3

Cavalry

4th New York -- 2 2

Cavalry

17th Pennsylvania -- -- 1

Cavalry

Second Division:

1st Maine Cavalry -- 48 51

16th Pennsylvania -- 1 1

4th Pennsylvania -- 4 4

Cavalry

Third Division:

2nd New York 2 66 71

Cavalry

5th New York 1 20 23

Cavalry

18th Pennsylvania -- 2 3

Cavalry

5th Michigan 1 47 50

Cavalry

6th Michigan -- 5 5

Cavalry

7th Michigan 3 41 44

Cavalry

1st Vermont -- 72 77

Cavalry

Total 7 310 335

HEADQUARTERS CAVALRY CORPS, March 30, 1864.

D. McM. GREGG,
Brigadier-General of Volunteers, Commanding.

Captain E. B. PARSONS,

Assistant Adjutant-General.