HEADQUARTERS, Jackson, July 17, 1863.

Major-General FRENCH, Commanding DIVISION:

General Cosby reports that the enemy have advanced; force not known. General Cosby's pickets have fired at them, and retired three times. General Johnston directs that you be informed of this, that you may keep your DIVISION in readiness for service at a moment's warning. Put a picket, consisting of a regiment and one gun, at a suitable position on the road you now occupy, to the rear.

By command of General Johnston:

BENJ. S. EWELL,
Assistant Adjutant-General.

SPECIAL ORDERS,
HDQRS. BRECKINRIDGE'S DIVISION, Numbers -. July 17, 1863.

This DIVISION will move in front of the DIVISION of Major-General French, on the Hillsborough road, at 4 a. m., to-morrow, in the following order: The brigade of Brigadier-General Adams will move in advance; that of Brigadier-General Stovall next; and that of Brigadier-General Helm last. The artillery will move in front of each brigade. The train will move at 3. 30 a. m. Baggage wagons of this DIVISION in advance; then baggage wagons of Major-General French's DIVISION; next the ordnance of this DIVISION, and then the ordnance of Major-General French. The whole of the train in front of this DIVISION. Brigadier-General Helm will detail one regiment to guard the ordnance and baggage train of this DIVISION.

By command of Major-General Breckinridge:

JOHN A. BUCKNER.

Assistant Adjutant-General.

ON PICKET, July 17, 1863.

Captain [W. F.] BULLOCK, Jr., Assistant Adjutant-GENERAL:

CAPTAIN: My pickets report the enemy in strong force near the school-house we passed this morning. They were dismounted in the woods. Not yet known whether dismounted cavalry or infantry.

J. J. PERRY.

[Indorsement.]

HEADQUARTERS COSBY'S CAVALRY BRIGADE,
One and a half miles from Brandon, July 17, 1863.

Respectfully forwarded. The school-house alluded to is on the road I came out upon, and situated about 4 1/2 miles from Jackson, at intersection of upper Brandon road with road leading to Ubank's Ferry.

In order to be at convenient point for receiving reports from pickets on both roads, I have established my headquarters near railroad crossing on upper Brandon and Jackson road, about 1 mile from former place.

G. B. COSBY.

JULY 17, 1863.

Captain BULLOCK, Assistant Adjutant-General.

The advance is now mounted. My pickets have fired and fallen back three times. Impossible to get in rear to find their force. A line of battle 3 miles from Brandon.

J. J. PERRY,

Captain, Commanding.