3. The Twelfth Corps will move through Fair Play, and take position between Jones' Four Corners and Marsh Run, in the general direction of the position taken by the Second and Fifth Corps.

4. The Third Corps will be massed in the vicinity of the Antietam Bridge, on the Boonsborough and Williamsport road, about the center of the line of advance, and held in readiness to move at short notice.

5. The points named in these instructions are intended to indicate the general direction and extent of the position to be taken, no to define it with exactitude. Corps commanders will select the ground to be occupied by their troops.

6. The cavalry will be so disposed as to protect the flanks and the line of communication.

7. These movements will be made as soon after daylight as practicable.

8. Corps commanders will report as soon as troops are in position. It is enjoined upon them to throw their pickets and advance guards well out, and to maintain as long as possible the greatest extent of ground practicable on their front. They will study with care the ground held by them, and in advance, in order that their reports upon it may convey all the information desired by the major-general commanding.

9. The Reserve Artillery will be moved forward on the Boonsborough and Hagerstown pike, to take a central position as nearly as the features of the ground will admit, so that batteries may be sent to all parts of the position in the shortest time practicable.

10. Corps commanders will take measures to have rations brought up in time to fill the haversacks as soon as emptied.

11. Headquarters will remain as at present established during the movements to-morrow.

By command of Major-General Meade:

S. WILLIAMS,

Assistant Adjutant-General.

HEADQUARTERS SECOND DIVISION, CAVALRY CORPS, July 10, 1863.

Colonel P. HUEY,
Commanding Second Brigade, Second Division:

COLONEL: After having uncovered the bridge on the Williamsport and Boonsborough pike, you will move on toward Williamsport, in front of the Fifth and Twelfth Corps. The detachment of the Third Division, which has gone toward Bakersville, has been ordered to communicate with you.

Very respectfully,

D. McM. GREGG,

Brigadier-General of Volunteers, Comdg. Second Division.

HEADQUARTERS SECOND DIVISION, CAVALRY CORPS, July 10, 1863.

Major KERWIN,
Thirteenth Pennsylvania Cavalry, Comdg. Detachments:

MAJOR: You will proceed to Smoketown, east of Boonsborough, with the Thirteenth Pennsylvania Cavalry and Scott's Nine Hundred.