McLean's Ford corresponding with those to be occupied by Longstreet at Blackburn's Ford. As already instructed, he will advance thence to the attack of the enemy's flank, on the Centerville road, about half way between Centerville and Mitchell's Ford, maintaining communication with General Longstreet on his left and General Ewell on his right. Supported by a section of Walton's battery, he will attack the enemy's line as nearly simultaneously with Longstreet's attack on the flank as practicable, but carefully guarding his own flank from a sudden attack by the enemy.

III. Brigadier-General Ewell, after falling back at or near Union Mills, will make all the necessary preparations for an attack of the enemy at Centerville. His advance to that end will commence as soon as he shall have ascertained that the advanced forces of the enemy have passed Centerville in pursuit of Bonham's brigade, and he will then move forward with prudence and necessary military precautions. He will receive information from these headquarters by signals or couriers as to the movements of the enemy. As already instructed, General Ewell will be careful to protect his right flank from an attack of the enemy in the direction of Fairfax Station or from Farris' Cross-Roads. His movements will be supported by his cavalry and four pieces of Walton's battery, and he will maintain communication on his left with General Jones, at McLean's Ford.

IV. Simultaneously with the Third and Fourth Brigades Colonel Early will concentrate his brigade about half a mile in rear of Union Mills Ford and there hold it in readiness to move in support of Ewell's brigade in the attack on the enemy at Centerville. Colonel Early will protect his rear with two pieces of Walton's battery, which will be attached to his brigade in due time. He will leave an additional company to guard the ford, which will be further protected by a piece from Walton's battery.

V. Colonel Cocke, as soon as it is known that General Ewell has engaged the enemy, will advance his brigade, supported by his cavalry and artillery, and vigorously join in the attack at Centerville.

VI. General Bonham, from his position at Mitchell's Ford, will assume the offensive with spirit simultaneously with General Longstreet's attack on the enemy's flank and rear.

VII. In the event of the movements thus indicated the headquarters of the general commanding will be established at once at McLean's farm-house.

By command of Brigadier-General Beauregard:

THOMAS JORDAN,

Acting Assistant Adjutant-General.

[2.]

SAVANNAH, July 17, 1861.

General S. COOPER:

Williams' regiment here actively preparing to march, but delayed a day or two because transportation engaged ahead for Florida regiment. Will reach Richmond by Monday morning at the furthest. Semmes' regiment on the southern part of the coast. Sent orders to march by first mail after receiving dispatch. Will press them on as fast as possible.

A. R. LAWTON,

Brigadier-General.

[2.]