General Lee, in personal command of Longstreet’s corps, reached the western end of Thoroughfare Gap about sunset, on the 28th, and the sound of artillery from the direction of Groveton indicated that Jackson and General Pope had come in collision.  Jackson had himself brought on this engagement by attacking the flank of one of General Pope’s various columns, as it marched across his front, over the Warrenton road, and this was the origin of the sound wafted to General Lee’s ears as he came in sight of Thoroughfare.  It was certainly calculated to excite his nerves if they were capable of being excited.  Jackson was evidently engaged, and the disproportion between his forces and those of General Pope rendered such an engagement extremely critical.  Lee accordingly pressed forward, reached the Gap, and the advance force suddenly halted:  the Gap was defended.  The Federal force posted here, at the eastern opening of the Gap, was small, and wholly inadequate for the purpose; but this was as yet unknown to General Lee.  His anxiety under these circumstances must have been great.  Jackson might be crushed before his arrival.  He rode up to the summit of the commanding hill which rises just west of the Gap, and dismounting directed his field-glass toward the shaggy defile in front.

[Footnote 1:  “Not knowing at the time where was the enemy.”—­General Porter.] and undecided what course to pursue.

[Illustration:  Lee Reconnoitring at Throughfare Gap.]

The writer of these pages chanced to be near the Confederate commander at this moment, and was vividly impressed by the air of unmoved calmness which marked his countenance and demeanor.  Nothing in the expression of his face, and no hurried movement, indicated excitement or anxiety.  Here, as on many other occasions, Lee impressed the writer as an individual gifted with the most surprising faculty of remaining cool and unaffected in the midst of circumstances calculated to arouse the most phlegmatic.  After reconnoitring for some moments without moving, he closed his glass slowly, as though he were buried in reflection, and deliberating at his leisure, and, walking back slowly to his horse, mounted and rode down the hill.

The attack was not delayed, and flanking columns were sent to cross north of the Gap and assail the enemy’s rear.  But the assault in front was successful.  The small force of the enemy at the eastern opening of the Gap retired, and, by nine o’clock at night, General Longstreet’s corps was passing through.

All the next morning (August 29th), Longstreet’s troops were coming into position on the right of Jackson, under the personal supervision of Lee.  By noon the line of battle was formed.[1] Lee’s army was once more united.  General Pope had not been able to crush less than one-half that army, for twenty-four hours nearly in his clutches, and it did not seem probable that he would meet with greater success, now that the whole was concentrated and held in the firm hand of Lee.