o the first rule of the military art, that a general should
never divide his force in the face of an enemy. That Lee ventured to
do so on this occasion can only be explained on one hypothesis, that
he did not highly esteem the military ability of his opponent. These
flank attacks undoubtedly, however, possessed a great attraction for
him, as they did for Jackson, and, in preferring such movement, Lee
was probably actuated both by the character of the troops on both
sides and by the nature of the country. The men of both armies were
comparatively raw levies, highly susceptible to the influence of
"surprise," and the appearance of an enemy on their flanks, or in
their rear, was calculated to throw them into disorder. The wooded
character of the theatre of war generally rendered such movements
practicable, and all that was requisite was a certain amount of daring
in the commander who was called upon to decide upon them. This daring
Lee repeatedly exhibited, and the uniform success of the movements
indicates his sound generalship.

To command the force which was now to go on the perilous errand of
striking General Pope's rear, General Lee selected Jackson, who had
exhibited such promptness and decision in the campaigns of the Valley
of Virginia. Rapidity of movement was necessary above all things,
and, if any one could be relied upon for that, it was the now famous
Stonewall Jackson. To him the operation was accordingly intrusted, and
his corps was at once put in motion. Crossing the Rappahannock at an
almost forgotten ford, high up and out of view of the Federal right,
Jackson pushed forward day and night toward Manassas, reached
Thoroughfare Gap, in the Bull Run Mountain, west of that place, passed
through, and completely destroyed the great mass of supplies in the
Federal depot at Manassas. The whole movement had been made with
such rapidity, and General Stuart, commanding the cavalry, had so
thoroughly guarded the flank of the advancing column from observation,
that Manassas was a mass of smoking ruins almost before General Pope
was aware of the real danger. Intelligence soon reached him, however,
of the magnitude of the blow aimed by Lee, and, hastily breaking
up his camps on the Rappahannock, he hurried to attack the force
assailing his communications.

The first part of General Lee's plan had thus fully succeeded. General
Pope, who had occupied every ford of the Rappahannock, so as to render
the passage difficult,