Immediately on the opening of the enemy's fire from the position occupied by the skirmishers of the highlanders, I ordered Captain Griffin to advance a section of his battery as soon as possible, place it in position, and open fire upon the enemy. I sent lieutenant Poe, of the Topographical Engineers, and Lieutenant Borrowe, of Griffein's battery, to make the necessary arrangements to protect the rear, and went in person to the point immediately threatened by the enemy and upon which he had opened his artillery. Our troops were in fine spirits, and obeyed their orders with alacrity. Meanwhile the whole command was withdrawn from the village in perfect order, although exposed to a heavy fire of artillery, and placed in suitable position either to continue the march ot Camp Advance, which the firing of the enemy had interrupted, or to advance upon and attack him in the event of his offering battle, or to receive in good order his attack, according to circumstances. Griffin's battery fired with great spirit and rapidity, and soon both silenced the enemy's guns and drove his infantry from their position. Moving tot he head of the column, I had indicated new positions for the two sections of Griffin's battery-one at Cook's place, the other on the opposite side of the road-and had give the necessary orders, the position being an admirable battle-field for the command, when you arrived upon the ground and assumed command. I now assumed command of the Seventy-ninth Regiment, which had up to this time been acting with the Chasseura, the whole under the command of Lieutenant-Colonel shaler, and placed it as a support to the battery of Captain Mott, just stationed at Cook's place. On Mott's change of position to the hill on the other side of the road, I stationed the Highlanders in the road, and remainder there till it was withdrawn, when the Highlanders became the rear guard of the column. I was then directed by you to cross into the fields to the right, and make for a cross-road which led from Falls Church to Langley,a nd in which it was feared the enemy might advance to annoy our flank. This duty was executed by the Highlanders in most excellent spirit and most of the time on the double-quick. No enemy was found in the cross-road. The Seventy-ninth was then marched to your headquarters and thence conducted tot he camp with the Chasseurs, both under the command of Lieutenant-Colonel Shaler, as they were marched out.

The reports form commanders accompanying this will be explain the details of the affair. The steadiness and good conduct of the troops under fire and throughout the day were most gratifying, and is an earnest of the good service their country has to expect front he. Every order was obeyed with alacrity. There was no flinging form fire. I left throughout the day the most perfect conference in the troops, and believe they could have been easily handled against a greatly superior force of the enemy. The arrangements of the pickets and skirmishers left nothing to be desired in the way of covering the reconnaissance. I myself served as an officer of Engineers in the second conquest of Mexico, and I present the operations of the 11th as a beautiful specimen of a reconnaissance in presence of the enemy. The operations of Lieutenant Poe showed me that the Engineers had los none of their ancient skill. Griffin was most gallant and prompt in the conduct of his battery. I examined with him and Lieutenant Poe the entire position of Lewinsville. It has great naturel advantages, is easily defensible, will require but a small amount of ordnance and should be permanently occupied without delay.

In returning my special thanks to commanders, officers, and men I will be pardoned if I present my particular obligations to Captain