Monday, September 1.—Fairfax Court House. At seven o’clock A. M. we proceeded to Germantown, going in position, facing Chantilly. Troops were coming in from Centreville all day. General McDowell’s corps, who lost nearly all their artillery, amongst them. An engagement, lasting from five o’clock P. M. till dark, was going on at Chantilly amidst a heavy thunder shower. Generals Kearney and Stevens were killed. About six o’clock P. M. we fell back to Fairfax Court House, camping on the same spot we occupied a year ago, while under Captain Reynolds, previous to the first battle of Bull Run.
Tuesday, September 2.—Fairfax Court House. During the whole night, troops were marching to the defences of Washington. Pope’s and McClellan’s armies are rapidly falling back, Sumner’s corps covering the retreat, as usual. We left the Court House at eight o’clock A. M., forming a line of battle on Flint Hill. Heavy clouds of dust, from the rebel columns, marching towards the Potomac, could be seen in the distance. Not being attacked, our line of march was resumed; but shortly afterwards, a rebel battery opened on our rear, directly from the town. General Sumner ordered one section of our battery, and the First Minnesota infantry, to take position, planting the two guns of the right section, one on each side of the road. Shortly after dark the enemy appeared. We could hear the unlimbering of the artillery. At that moment we opened lively with shell and canister, while Colonel Sully threw his regiment across the road, and kept up a brisk musketry fire on the advancing cavalry of the enemy. Being unable to use their artillery, the rebels retreated instantly. Seven men of the First Minnesota were killed and wounded. One of our limber-chests was upset, the pole being broken by the horses, injuring John Setton, driver, and one horse. Colonel Sully, anxious to fall back, advised Captain Tompkins not to lose any time, and if needs be, to abandon the gun. Captain Tompkins replied, he would carry the gun along or share the fate of it. We all went to work, tying the two guns and limbers together with ropes and straps. In the vicinity of Vienna, a body of cavalry made a charge on our column, firing at us with pistols and carbines. The First Maryland Cavalry, and Company I, First Minnesota, left us without offering any resistance to them. The greatest excitement prevailed for some time. General Sumner gave credit to our battery for not having left the guns. Some said the charge was made by a party of our own cavalry by mistake; but the dead and wounded, found in rebel uniform, contradicted that. After a weary march, we arrived near Fort Ethan Allen, at three o’clock A. M.
Wednesday, September 3.—Sumner’s corps marched across the Chain Bridge to Tenallytown, and went to camp.
Thursday, September 4.—Tenallytown, Maryland. Heavy cannonade on the upper Potomac.
Friday, September 5.—Tenallytown. The rebel army has crossed the Potomac. We left Tenallytown this morning. Marched to Rockville, twelve miles from Washington, and went to camp three miles from that place. New clothes were issued to-night.
Saturday, September 6.—Near Rockville. This morning the cavalry and our battery advanced several miles, going in position on a hill. Thirty cavalrymen were captured last night. Scouts coming in the afternoon informed of the enemy’s presence, only four miles from us. We fell back until, to our surprise, we found the whole of the Second corps in line of battle. Our battery took position immediately. The whole road was covered by our artillery.
Sunday, September 7.—Near Rockville. The rebel army occupies Frederick City. Our cavalry dashed into Poolesville. We marched only six miles to-day.
Tuesday, September 9.—We started by ten o’clock, A. M., and marched seven miles. Our cavalry had a fight at Barnesville.
Wednesday, September 10.—March to Clarksburg. Our advance is getting very slow.
Thursday, September 11.—March to Hyattstown, eight miles from Frederick. We formed in line of battle on a hill in front of the town. Our skirmishers advanced, but could not find the enemy.