The conduct of the troops was all that I could desire or expect, and they deserve success so far it can be deserved by heroic valor and fortitude . More may have been required of them than they were able to perform, but my admiration of their noble qualities and confidence in their ability to cope successfully with the enemy has suffered no abatement from the issue of this protracted and sanguinary conflict . Owing to the strength of the enemy's position, and the reduction of our ammunition, a renewal of the engagement could not be hazarded and the difficulty of procuring supplies rendered it impossible to continue longer where we were . Such of the wounded as were in condition to be removed, and part of the arms collected on the field, were ordered to Williamsport. The army remained at Gettysburg during the 4th, and at night began to retire by the road to Fairfield, carrying with it about 4, 000 prisoners . Nearly 2, 000 had previously been paroled, but the enemy's numerous wounded that had fallen t into our hands after the first and second day's engagement were left behind . Little progress was made that night, owing to a severe storm, which greatly embarrasses our movements . The rear of the column did not leave its position near Gettysburg until after daylight on the 5th . The march was continued during that day without interruption from the enemy, excepting an unimportant demonstration upon rear in the afternoon when near Fairfield, which was easily checked . Part of our train moved by the road through Fairfield, and the rest by way of Cashtown, guarded by General Imboden. In passing through the mountain in advance of the column, the great length of the trains exposed them to attack by the enemy's cavalry, which captured a number of wagons and ambulances, but they succeeded in reaching Williamsport without serious loss. They were attacked at that place on the 6th by the enemy's cavalry, which was gallantly repulsed by General Imboden . Attacking force was subsequently encountered and driven off by General Stuart, and pursued for several miles in the direction of Boonsborough . The army, after an arduous march, rendered more difficult by the rains, reached Hagerstown of the afternoon of July 6 and morning of the 7th. The Potomac was found to be so much swollen by the rains that had fallen almost incessantly since our entrance into Maryland as to be unfordable . Our communication with the south side were thus interrupted, and it was difficult to procure either ammunition or subsistence, the latter difficulty being enhanced by the high waters impending the working off the neighboring mills . The trains with the wounded and prisoners were compelled to await at Williamsport the subsiding of the river and the construction of boats, as the pontoon bridge left at Falling Waters had been partially destroyed . The enemy had not yet made his appearance, but as he was in condition to obtain large re-enforcement, and our situation, for the reasons above mentioned, was becoming daily more embarrassing, it was deemed advisable to recross the river . Part of the pontoon bridge was recovered and new boats built, so that by the 13th a good bridge was thrown over the river at Falling Waters. The enemy in force reached our front on the 12th . A position had been previously selected to cover the Potomac from Williamsport to Falling Waters, and an attack awaited during that the succeeding day . This did not take place, though the two armies were in close proximity, the enemy being occupied in fortifying his own