I arrived at Washington on the 4th of August, and the next day received instructions from General Halleck to report to General Grant at Monocacy Junction, whither he had gone direct from City Point, in consequence of a characteristic despatch from the President indicating his disgust with the confusion, disorder, and helplessness prevailing along the upper Potomac, and intimating that Grant’s presence there was necessary.

In company with the Secretary of War I called on the President before leaving Washington, and during a short conversation Mr. Lincoln candidly told me that Mr. Stanton had objected to my assignment to General Hunter’s command, because he thought me too young, and that he himself had concurred with the Secretary; but now, since General Grant had “ploughed round” the difficulties of the situation by picking me out to command the “boys in the field,” he felt satisfied with what had been done, and “hoped for the best.”  Mr. Stanton remained silent during these remarks, never once indicating whether he, too, had become reconciled to my selection or not; and although, after we left the White House, he conversed with me freely in regard to the campaign I was expected to make, seeking to impress on me the necessity for success from the political as well as from the military point of view, yet he utterly ignored the fact that he had taken any part in disapproving the recommendation of the general-in-chief.

August 6, I reported to General Grant at the Monocacy, and he there turned over to me the following instructions, which he had previously prepared for General Hunter in the expectation that general would continue to command the department: 

“Headquarters in the field,
“Monocacy Bridge, Md., Aug. 5, 1864.

“General:  Concentrate all your available force without delay in the vicinity of Harper’s Ferry, leaving only such railroad guards and garrisons for public property as may be necessary.

“Use in this concentration the railroad, if by so doing time can be saved.  From Harper’s Ferry, if it is found that the enemy has moved north of the Potomac in large force, push north, following and attacking him wherever found; following him, if driven south of the Potomac, as long as it is safe to do so.  If it is ascertained that the enemy has but a small force north of the Potomac, then push south the main force, detaching, under a competent commander, a sufficient force to look after the raiders and drive them to their homes.  In detaching such a force, the brigade of cavalry now en route from Washington via Rockville may be taken into account.

“There are now on the way to join you three other brigades of the best of cavalry, numbering at least five thousand men and horses.  These will be instructed, in the absence of further orders, to join you by the south side of the Potomac.  One brigade will probably start to-morrow.