"IV. In the event of the defeat of the Enemy, the troops at Mitchell's Ford and Stone Bridge, especially the Cavalry and Artillery, will join in the pursuit, which will be conducted with vigor but unceasing prudence, and continued until he shall have been driven beyond the Potomac."
And it is not without interest to note Beauregard's subsequent indorsement on the back of these Special Orders, that: "The plan of attack prescribed within would have been executed, with modifications affecting First and Fifth Brigades, to meet the attack upon Blackburn's Ford, but for the expected coming of General Johnston's command, which was known to be en route to join me on [Thursday] the 18th of July."
The knowledge thus possessed on Thursday, the 18th, by Beauregard, that Johnston's Army is on its way to join him, is of infinite advantage to the former. On the other hand, the complete ignorance, at this time, of McDowell on this point,—and the further fact that he has been lulled into a feeling of security on the subject, by General Scott's emphatic assurance to him that "if Johnston joins Beauregard, he shall have Patterson on his heels"—is a great disadvantage to the Union general.
Were McDowell now aware of the real Military situation, he would unquestionably make an immediate attack, with the object of crushing Beauregard before Johnston can effect a junction with him. It would then be a mere matter of detail for the armies of McDowell, McClellan, and Patterson, to bag Johnston, and bring the armed Rebellion to an inglorious and speedy end. But Providence—through the plottings of individuals within our own lines—wills it otherwise.
Long before this, Patterson has been informed by General Winfield Scott of the proposed movement by McDowell upon Manassas,—and of its date.
On Saturday, July 13th, General Scott telegraphed to Patterson: "I telegraphed to you yesterday, if not strong enough to beat the Enemy early next week, make demonstrations so as to detain him in the Valley of Winchester; but if he retreats in force toward Manassas, and it be too hazardous to follow him, then consider the route via Keys Ferry, Leesburg, etc."
On Wednesday, the 17th, Scott telegraphs to Patterson: "I have nothing official from you since Sunday (14th), but am glad to learn, through Philadelphia papers, that you have advanced. Do not let the Enemy amuse and delay you with a small force in front whilst he re-enforces the Junction with his main body. McDowell's first day's work has driven the Enemy beyond Fairfax Court House. The Junction will probably be carried by to-morrow."
On Thursday, the 18th, Patterson replies that to attack "the greatly superior force at Winchester when the three months volunteers' time was about up, and they were threatening to leave him—would be most hazardous" and then he asks: "Shall I attack?"
Scott answers the same day: "I have certainly been expecting you to beat the Enemy. If not, to hear that you had felt him strongly, or, at least, had occupied him by threats and demonstrations. You have been at least his equal, and, I suppose, superior in numbers. Has he not stolen a march and sent re-enforcements toward Manassas Junction? A week is enough to win victories," etc.
Patterson retorts, on the same day: "The Enemy has stolen no march upon me. I have kept him actively employed, and by threats, and reconnaissances in force, caused him to be re-enforced. I have accomplished in this respect more than the General-in-Chief asked, or could well be expected, in face of an Enemy far superior in numbers, with no line of communication to protect."