below the bridge, and were advancing through a wood in the low grounds at our left, with an evident purpose to flank us. To intercept this movement, I ordered forward into the road still lower down two of Carlisle's brass howitzers, a few rounds from which, quickly served, drove the rebels from the wood and back to the other side of the stream. It was not long after this that the unpleasant intelligence came of our Army being in retreat from the front across the ford above, and the order was given to fall back on Centreville. The retreat of my brigade, being now in the rear of our division, was conducted in the reverse order of our march in the morning, the Second New York moving first, and being followed by thee Second Ohio and First Ohio, the two latter regiments preserving their lines in good degree, rallying together and arriving at Centreville with closed ranks, and sharing comparatively little in the panic which occasioned more by the fears of frightened teamsters, and of hurrying and excited civilians [who ought never to have been there], than even by the needless disorder and want of discipline of straggling soldiers.

Near the house which was occupied as a hospital for the wounded, about a mile from the battle-ground, a dashing charge was made upon the retreating column by a body of secession cavalry, which was gallantly repelled, and principally by two companies of the Second Ohio, with loss on both sides. Here also, in this attack, occurred some of the casualties to the Second New York Regiment. From this point to Centreville a portion of the First Ohio was detailed, under command of Lieutenant-Colonel Parrott, and acted efficiently as a rear guard, covering the retreat.

Arrived at Centreville, I halted the two Ohio regiments on the hill, and proceeded to call on General McDowell, whom I found engaged in forming the reserve of the Army and other troops in line of battle to meet an expected attack that night of the enemy at that point. I offered him our services, premising, however, that unfed and weary troops, who had been seventeen hours on the march and battle-field, might not be very effective, unless it were to be posted as a reserve in case of later emergency. General McDowell directed me to take them to the foot of the hill, there to stop and encamp. This I did, establishing the two regiments together in the wood to the west of the turnpike. After resting here about two hours, I was notified that your division, with the rest of the forces under the general commanding, were leaving Centreville, and received your order to fall back on Washington. I took the route by Fairfax Court-House, and thence across to Vienna, arriving at the latter place at 3.30 a.m. of the 22nd, and there resting the troops for two hours in an open field. During the march we did what was possible to cover the rear of the scattered column then on the road.

Two miles, or less, this side of Vienna, Colonel McCook, with the main body of his regiment, turned upon the road leading to the Chain Bridge over the Potomac, thinking it might be a better way, and at the same time afford by the presence of a large and organized body protection to any stragglers that might have taken that route. Lieutenant-Colonel Mason, with the Second Ohio, marched in by the way of Falls Church and Camp Upton.

The return of the Ohio regiments to Washington was made necessary by the fact that, their term of service having expired, they are at once to be sent home to be mustered out of service.

Not having been able to obtain yet complete or satisfactory returns