ttle, if any, towards
success in Lee's campaign. Stuart's advance reached the Confederate
left _via_ Dover and Carlisle, Pennsylvania, late on the afternoon
of the second day of the battle, his troopers and horses in a
somewhat exhausted condition. The consensus of opinion among
military critics was then, and since is, that Lee committed a great
strategic error in authorizing his main cavalry force to be separated
from close contact with the right of his moving army. General Lee
seems to have come to this conclusion himself, as frequently, in
his official reports of the campaign, he deplores the absence of
his cavalry and his consequent inability to obtain reliable
information of the movements of the Army of the Potomac.( 6)
Longstreet severely criticises Stuart's raid, and attributes to
the absence of the cavalry, in large part, the failure of the
Gettysburg campaign.( 7) Cavalry, under an energetic commander,
are the _eyes and ears_ of a large army, especially when it is on
an active campaign against a vigilant enemy.

Having with some particularity traced the main bodies composing
Lee's army, as to time and routes, to the vicinity of Gettysburg,
it remains to briefly follow the Army of the Potomac to the same
place. While some of its corps moved earlier, the headquarters of
that army did not leave Falmouth until the 14th of June, when it
was established at Dumfries; on the next day at Fairfax Station,
on the 18th at Fairfax Court-House, on the 26th at Poolesville,
Maryland, and the next day at Frederick, Maryland, where Meade
succeeded Hooker. Before the Army of the Potomac left Falmouth a
division of the Sixth Corps had been thrown across the river to
observe the enemy, but it did not attack him, and was withdrawn on
the 13th.

Meade found his army, mainly, in the vicinity of Frederick, though
some of his corps had passed northward and others were moving up
by converging lines, the Sixth Corps having just arrived at
Poolesville from Virginia. June 29th, Meade moved his headquarters
from Frederick to Middleburg, the next day to Taneytown, Maryland,
about fifteen miles south of Gettysburg.

The movements of the Army of the Potomac were such as to cover
Washington and Baltimore, and at the same time bring, as soon as
possible, the invading army to battle.

The First, Eleventh, and Third Corps, under Major-General John F.
Reynolds, were in the advance on Gettysburg on July 1st, the First
Corps leading, and