"CITY POINT, August 12, 1864—9 A. M.
"MAJOR-GENERAL HALLECK
"Inform General Sheridan that it is now certain two (2) divisions of infantry have gone to Early, and some cavalry and twenty (20) pieces of artillery. This movement commenced last Saturday night. He must be cautious, and act now on the defensive until movements here force them to detach to send this way. Early's force, with this increase, cannot exceed forty thousand men, but this is too much for General Sheridan to attack. Send General Sheridan the remaining brigade of the Nineteenth Corps.
"I have ordered to Washington all the one-hundred-day men. Their time will soon be out, but for the present they will do to serve in the defenses.
"U. S. GRANT, Lieutenant-General."
The despatch explained the movement from Culpeper, and on the morning of the 15th Merritt's two remaining brigades were sent to Front Royal to oppose Anderson, and the Sixth Corps withdrawn to the north side of Cedar Creek, where it would be in a position enabling me either to confront Anderson or to act defensively, as desired by General Grant.
To meet the requirements of his instructions I examined the map of the valley for a defensive line—a position where a smaller number of troops could hold a larger number—for this information led me to suppose that Early's force would greatly exceed mine when Anderson's two divisions of infantry and Fitzhugh Lee's cavalry had joined him. I could see but one such position, and that was at Halltown, in front of Harper's Ferry. Subsequent experience convinced me that there was no other really defensive line in the Shenandoah Valley, for at almost any other point the open country and its peculiar topography invites rather than forbids flanking operations.
This retrograde movement would also enable me to strengthen my command by Grower's division of the Nineteenth Corps and Wilson's cavalry, both of which divisions were marching from Washington by way of Snicker's Gap.
After fully considering the matter, I determined to move back to Halltown, carrying out, as I retired, my instructions to destroy all the forage and subsistence the country afforded. So Emory was ordered to retire to Winchester on the night of the 15th, and Wright and Crook to follow through Winchester to Clifton the next night.
For the cavalry, in this move to the rear, I gave the following instructions: