Hooker’s right flank, of less than ten thousand men, was thus isolated from the rest of the army, with no supports within two miles.

And yet the full evidence of Jackson’s whereabouts was before him.  There had been a constant feeling of the Union lines (by Stuart’s cavalry and some infantry skirmishers) all day, gradually working from east to west.  This fact was noticed by many officers, and is particularly referred to by Pleasonton, Warren, and Howard.  Jackson’s columns and trains had been strongly reconnoitred, their force estimated, and their direction noted.  The question as to what might be the objective of such a movement, had been the main topic of discussion during the day throughout the right of the army.

At noon a cavalry picket on the plank road was driven in, and gave notice of the passing of a heavy column a mile beyond our lines.  About 3.30 P.M. the leading divisions of Jackson’s corps, arriving on the old turnpike, sent a party forward to feel our lines, and a ten-minutes’ skirmish resulted, when the Confederate party withdrew.  There had been a number of minor attacks on our outlying pickets, some of them occurring when Gen. Howard was present.  All these facts were successively reported to headquarters.

About the same time two men, sent out as spies, came in, and reported the enemy crossing the plank road on our right, in heavy columns.  These men were despatched by Howard to Hooker, with instructions to the officer accompanying them to see that Hooker promptly received their information.  On the other hand, a half-hour before Jackson’s attack came, Howard sent a couple of companies of cavalry out the plank road to reconnoitre.  These men, from negligence or cowardice, failed to go far enough to ascertain the presence of Jackson, and returned and reported all quiet.  This report was, however, not forwarded to Hooker.

There was not an officer or man in the Eleventh Corps that afternoon who did not discuss the possibility of an attack in force on our right, and wonder how the small body thrown across the road on the extreme flank could meet it.  And yet familiar with all the facts related, for that they were reported to him there is too much cumulative evidence to doubt, and having inspected the line so that he was conversant with its situation, Hooker allowed the key of his position to depend upon a half-brigade and two guns, facing the enemy, while the balance of the wing, absolutely in the air, turned its back upon the general whose attack was never equalled for its terrible momentum during our war, or excelled in any, and whose crushing blows had caused the brave old Army of the Potomac more than once to stagger.

Moreover, the “key of the position” was confided to a corps which was not properly part of the Army of the Potomac, and untried as yet.  For not only had the Eleventh Corps, as a corps, seen no active service, but the most of its regiments were made up of raw troops, and the elements of which the corps was composed were to a degree incongruous.  Of itself this fact should have caused Hooker to devote serious attention to his right flank.