Records_, vol. xxvii., Part II., pp. 88-197.

CHAPTER II
Invasion of Pennsylvania--Campaign and Battle of Gettysburg--Lee's
Retreat Across the Potomac, and Losses in Both Armies

At Harper's Ferry, June 16th, I was assigned to command a brigade
under General W. H. French, a regular officer. General Joseph
Hooker, in command of the Army of the Potomac, June 25th, ordered
French to be ready to march at a moment's notice. French took
position on Maryland Heights, where, June 27th, Hooker visited him
and gave him orders to prepare to evacuate both the Heights and
Harper's Ferry. French had under him there about 10,000 effective
men. Halleck, on being notified of Hooker's purpose to evacuate
these places and to unite French's command with the Army of the
Potomac for the impending battle, countermanded Hooker's order;
thereupon the latter, by telegram from Sandy Hook, requested to be
relieved from the command of that army. His request being persisted
in, he was, on June 28th, relieved, and Major-General George G.
Meade was, by the President, assigned to succeed him. Meade, also
feeling in need of reinforcements, on the same day asked permission
to order French, with his forces, to join him. Halleck, though
placing French under Meade's command, did not consent to this.
French, however, with all his troops (save my brigade), under orders
from Washington, abandoned Harper's Ferry and Maryland Heights,
and became a corps of observation to operate in the vicinity of
Frederick, Maryland, in the rear of the Army of the Potomac. And
though no enemy was threatening, nor likely to do so soon, I was
ordered to dismantle the fortified heights, load the guns and stores
on Chesapeake and Ohio Canal boats, and escort them to Washington,
repairing the canal and locks on the way. This work was done
thoroughly, and we arrived with a fleet of twenty-six boats in
Washington shortly after midnight, July 4, 1863. It was my first
visit to that city.

Under orders from Halleck, I started on the 6th, by rail, to reoccupy
Harper's Ferry, but was stopped by Meade at Frederick, and there
again reported to French. French had been assigned to command the
Third Army Corps (to succeed General Daniel E. Sickles, wounded at
Gettysburg), and his late command became the Third Division of that
corps, under Elliott; my brigade, consisting of the 110th and 122d
Ohio, 6th Maryland, and 138th Pennsylvania Infantry regiments,
became the Second Brig