was a critical moment.

Meanwhile, Jackson's operations in the Shenandoah Valley had so startled
and astounded the Federals that he was able to march, June 20-25,
unobserved, over the passes of the Blue Ridge Mountains to Lee's
assistance. A series of battles began June 26 at Mechanicsville on
McClellan's right, near where Johnston had fought. But the failure of
Jackson to arrive and begin the attack, according to agreement, caused
the first Confederate onset to fail, with heavy losses to the South. The
next day, however, the tide turned the other way and Lee routed
McClellan at Gaines' Mill. McClellan now retreated across White Oak
Swamp towards Harrison's Landing on the James. The weather was hot, the
ground soft from rains, and the underbrush so thick and tangled that men
could not see each other at a distance of ten paces, save in the narrow
roads or small clearings. Realizing the difficulties under which his
opponent labored, Lee ordered hasty pursuit, and ineffective blows were
struck at Savage's Station and in White Oak Swamp. Jackson again failed
to maintain the great reputation he had won in the Valley, and Magruder,
Holmes, and Huger, other lieutenants of Lee, not knowing their own
country as well as did the Federals, suffered their commands to be lost
in the wilderness and thus aided McClellan in his escape from a
dangerous situation. On July 1 the retreating Union army gathered, still
devoted to its commander, on Malvern Hill, within support of the Federal
gunboats in the James River below. The Confederates, confident and
expectant, poured out of the woods from every direction, formed in
battle array, and charged over open fields and rising ground toward the
two hundred and fifty great guns which had been dragged for weeks
through the swamps in the hope of just such an opportunity. The attempt
of Lee to carry this impregnable position lost the Confederates as many
brave men as all the other six days of unremitting warfare. McClellan
held his own till night; Lee withdrew to the neighboring thickets,
surprised at the resolute strength of an opponent who had avoided battle
at every turn since June 26.

The week of fighting and scouring the woods had cost the North nearly
16,000 men; the South, 20,000. The retreat on July 2 to Harrison's
Landing was McClellan's confession of failure, which sorely distressed
his superiors in Washington and greatly depressed the spirits of the
North. Lee's first essay at war on a