On the morning of the 8th, some severe skirmishing commenced between the advance of the Fifth Corps and the enemy, showing that the latter was falling back from the Wilderness toward Spotsylvania Court-House. At break of day I was directed to make a reconnaissance of the country along the Brock road and parallel to the Po River, to select a good position for the Second Corps to take up in the event of the enemy attempting to strike our flank. About noon I was directed to remain with Major-General Hancock and perform any services he might require. During the day an examination was made toward the west along the Catharpin road as far as Corgin's Bridge, across the Po; the columns of the enemy could be distinctly seen moving south. Toward evening he made was easily repulsed. Camp of the headquarters was early in the morning established at Widow Lewis', but later in the day moved to Stewart's between the Brock road and the one from Piney Branch Church. On the 9th, the officers of Engineers, with part of the Engineer Battalion, were engaged in assisting the different corps in strengthening their positions by intrenchments. The army remained comparatively quiet during the day; it was, however, called upon to mourn the death of one of its greatest leaders, the gallant and noble hearted Sedgwick, who during the morning was killed by a sharpshooter while examining the position of the enemy in advance of Alsop's house.

Early on the 10th, the Second Corps was advanced across the Po by pontoon bridge. Subsequently, by order of the commanding general, I guided Gibbon's and Birney's divisions back again across the river and placed them in position to the rear and right of the Fifth Corps, where they were massed to make a combined assault. Late in the evening it was most persistently made through a dense thicket, and although unsuccessful after repeated efforts, proved the great bravery of our troops. Lieutenant Mackenzie was on the same day engaged on a reconnaissance to the front of the Sixth Corps, and, in company with General Russell, selected the point of attack so successfully made by Upton's brigade of that corps. Headquarters camp moved toward evening from Stewart's to near Alsop's. On the 11th the lines were slightly advanced, and during the night the Second Corps was moved to the left preparatory to a general assault along the whole line at early dawn. Captain Mendell was directed to guide it into position. A constant rain fell during the entire day, making the ground very heavy. The impenetrable mist which veiled the movement favored the attack, and rendered its first fruits most brilliant, but the long continued marching, and a drizzling rain, tended to dampen the ardor of the assaulting columns, already over-fatigued by seven days' constant fighting.

The 12th of May will long be remembered for the fierce battle which raged and surged along the whole line from the first peep of dawn until darkness had for hours fallen over the contending hosts. Fourteen hours of most furious fighting had failed to dislodge the enemy from his strong position. In the course of the afternoon Major Duane and myself rode over the ground between the right of the Sixth Corps and the old Court-House road to select a line, refused from the crossing of the Po, for one division of the Fifth Corps (Crawford's) to hold, so as to relieve the other two for other movements. The Army of the Potomac extended to-day from the Po River to the Ny. Headquarters camp moved early in the morn-