Johnston loses no time in deciding that it is his duty to prevent, if possible, disaster to Beauregard's Army; that to do this he must effect a junction with him; and that this necessitates either an immediate fight with, and defeat of, Patterson,—which may occasion a fatal delay—or else, that Union general must be eluded. Johnston determines on the latter course.
Leaving his sick, with some militia to make a pretense of defending the town in case of attack, Johnston secretly and rapidly marches his Army, of 9,000 effective men, Southeasterly from Winchester, at noon of Thursday, the 18th; across by a short cut, wading the Shenandoah River, and then on through Asby's Gap, in the Blue Ridge, that same night; still on, in the same direction, to a station on the Manassas Gap railroad, known as Piedmont, which is reached by the next (Friday) morning,—the erratic movements of Stuart's Cavalry entirely concealing the manoeuvre from the knowledge of Patterson.
From Piedmont, the Artillery and Cavalry proceed to march the remaining twenty-five miles, or so, to Manassas Junction, by the roads. The 7th and 8th Georgia Regiments of Bartow's Brigade, with Jackson's Brigade,—comprising the 2d, 4th, 5th, 27th and 33d Virginia Regiments—are embarked on the cars, and hurriedly sent in advance, by rail, to Manassas, reaching there on that same (Friday) afternoon and evening. These are followed by General Johnston, with Bee's Brigade—comprising the 4th Alabama, 2d Mississippi, and a battalion of the 11th Mississippi—which arrive at Manassas about noon of Saturday, the 20th of July, the balance of Johnston's Infantry being billed for arrival that same day, or night.
Upon Johnston's own arrival at Manassas, Saturday noon,—the very day that Patterson ascertains that "the bird has flown,"—after assuming command, by virtue of seniority, he proceeds to examine Beauregard's position. This he finds "too extensive, and the ground too densely wooded and intricate," to be learned quickly, and hence he is impelled to rely largely upon Beauregard for information touching the strength and positions of both the Rebel and Union Armies.
Beauregard has now 21,833 men, and 29 pieces of artillery of his own "Army of the Potomac." Johnston's and Holmes's junction with him has raised the Rebel total to 32,000 effectives, and 55 guns. McDowell, on the other hand, who started with 30,000 effectives, finds himself on the 19th—owing to the departure of one of his regiments and a battery of Artillery, because of the expiration of their term of enlistment,—with but "28,000 men at the utmost."—[Comte de Paris.]
On the evening of Saturday, the 20th of July, Johnston and Beauregard hold an important consultation. The former feels certain that Patterson, with his more than 20,000 effectives, will now lose no time in essaying a junction with McDowell's Army, and that such junction will probably be effected by July 22nd. Hence he perceives the necessity of attacking McDowell, and if possible, with the combined Rebel Forces, whipping him before Patterson can come up to his assistance.
At this consultation it is agreed by the two Rebel generals to assume the offensive, at once. Beauregard proposes a plan of battle—which is an immediate general advance of the Rebel centre and left, concentrating, from all the fords of Bull Run, upon Centreville, while the Rebel right advances toward Sangster's cross-roads, ready to fall either on Centreville, or upon Fairfax Court House, in its rear, according to circumstances.
The plan proposed, is accepted at once by Johnston. The necessary order is drawn up by Beauregard that night; and at half past four o'clock on Sunday morning, July 21st, Johnston signs the written order. Nothing now remains, apparently, but the delivery of the order to the Rebel brigade commanders, a hurried preparation for the forward movement, and then the grand attack upon McDowell, at Centreville.
Already, no doubt, the fevered brain of Beauregard pictures, in his vivid imagination, the invincible thunders of his Artillery, the impetuous advance of his Infantry, the glorious onset of his Cavalry, the flight and rout of the Union forces, his triumphal entry into Washington—Lincoln and Scott and the Congress crouching at his feet—and the victorious South and conquered North acclaiming him Dictator! The plan is Beauregard's own, and Beauregard is to have command. Hence all the glory of capturing the National Capital, must be Beauregard's. Why not? But "man proposes, and God disposes." The advance and attack, are, in that shape, never to be made.
McDowell, in the meantime, all unconscious of what has transpired in the Shenandoah Valley, and between there and Manassas; never dreaming for an instant that Patterson has failed to keep Johnson there—even if he has not attacked and defeated him; utterly unsuspicious that his own lessened Union Army has now to deal with the Forces of Johnston and Beauregard combined—with a superior instead of an inferior force; is executing a plan of battle which he has decided upon, and announced to his general officers, on that same Saturday evening, at his Headquarters in Centreville.