"still I could not have believed that
Jackson would have hazarded a decisive engagement, so far from the
main body, without expecting reinforcements; so, to be prepared for
such a contingency, I set to work during the night to bring together
all the troops within my reach. I sent an express after Williams'
division, requesting the rear brigade, about twenty miles distant, to
march all night and join me in the morning. I swept the posts in rear
of almost all their guards, hurrying them forward by forced marches,
to be with me at daylight."* (* O.R. volume 12 part 1 page 341.)

General Banks, hearing of the engagement on his way to Washington,
halted at Harper's Ferry, and he also ordered Williams' division to
return at once to Winchester.

One brigade only,* (* Abercrombie's, 4500 men and a battery. The
brigade marched to Warrenton, where it remained until it was
transferred to McDowell's command.) which the order did not reach,
continued the march to Manassas. This counter-movement met with
McClellan's approval. He now recognised that Jackson's force,
commanded as it was, was something more than a mere corps of
observation, and that it was essential that it should be crushed.
"Your course was right," he telegraphed on receiving Banks' report.
"As soon as you are strong enough push Jackson hard and drive him
well beyond Strasburg...The very moment the thorough defeat of
Jackson will permit it, resume the movement on Manassas, always
leaving the whole of Shields' command at or near Strasburg and
Winchester until the Manassas Gap Railway is fully repaired.
Communicate fully and act vigorously."* (* O.R. volume 12 part 3 page
16.)

8000 men (Williams' division) were thus temporarily withdrawn from
the force that was to cover Washington from the south. But this was
only the first step. Jackson's action had forcibly attracted the
attention of the Federal Government to the Upper Potomac. The
President was already contemplating the transfer of Blenker's
division from McClellan to Fremont; the news of Kernstown decided the
question, and at the end of March these 9000 men were ordered to West
Virginia, halting at Strasburg, in case Banks should then need them,
on their way.* (* Blenker's division was at Hunter's Chapel, south of
Washington, when it received the order.) But even this measure did
not altogether allay Mr. Lincoln's apprehensions. McClellan had
assured him, on April 1, that 73,000 men would be left for the
defen