Letters.
Confidential.
Headquarters Army of the Potomac, July 20, 1861.
Special Order, No. —
The following order is published for the information of division and brigade commanders: 1st. Brigadier-General Ewell's brigade will march via Union Mills Ford, and place itself in position of attack upon the enemy.
It will be held in readiness, either to support attack upon Centreville, or to move in the direction of Sangster's Cross-roads, according to circumstances.
The order to advance will be given by the commander-in-chief. 2d. Brigadier-General Jones's brigade, supported by Colonel Early's brigade, will march via McLean's Ford to place itself in position of attack on the enemy, or about the Union Mill and Centreville road.
It will be held in readiness, either to support the attack on Centreville, or to move in the direction of Fairfax Station, according to circumstances, with its right flank toward the left of Ewell's command, more or less distant according to the nature of the country and attack.
The order to advance will be given by the commander-in-chief. 3d. Brigadier-General Longstreet's brigade, supported by Brigadier-General Jackson's brigade, will march via McLean's Ford, to place itself in position of attack upon the enemy on or about the Union Mill and Centreville road.
It will be held in readiness, either to support the attack on Special Order, No. —

