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 Brigade of this division. This brigade (with, later, three regiments added) was not broken up during the war, and was generally known as "_Keifer's Brigade_." It is not my purpose to attempt to write the full story of the battle of Gettysburg, the greatest, measured by the results, of the many great battles of the war. Gettysburg marks the high tide of the Rebellion. From it dates the certain downfall of the Confederacy, though nearly two years of war followed, and more blood was spilled after Lee sullenly commenced his retreat from the heights of Gettysburg than before.