On the afternoon of the 30th ultimo, I was directed to report with the division to General Fitz John Porter, who, as I was informed, would hold us as a reserve to support the attack on the enemy's center. I found General Porter's troops formed in rear of a piece of woods about one-half a mile to the right of the point at which the division had been engaged the day previous. On reporting to General Porter, and informing him of the order under which I came he directed me to post the division on the right of his own troops, and to make the attack simultaneously with himself.

The division was drawn up in seven lines, composed as follows: First and second, Hatch's brigade; third and fourth, Patrick's brigade; fifth and sixth, Gibbon's brigade; seventh, Doubleday's brigade; the Second U. S. Sharpshooters being advanced as skirmishers in the woods. At the word given by General Porter the division advanced, with an interval of 50 yards between the lines. The enemy were very strongly posted behind an old did used railroad embankment, where, according to their own statement, they had been awaiting us for two days. This railroad embankment, which runs parallel to the edge of the woods where we entered in front of our right wing, bears more to the rear on reaching a piece of open ground in front of our left wing.

After passing through the woods and reaching the open space the left wing of the first line was obliged to make a partial wheel to the right to enable them to approach the enemy. This movement was executed under a heavy fire of artillery on the left and of musketry from the woods directly in our front.

Seeing the great disadvantages under which the first and second lines labored, the others, as they came up, were ordered to oblique more to the right, to enable them to attack the troops behind the railroad embankment, and also to get a partial flank fire upon that portion of the embankment which crosses the open field. The contest for the possession of this embankment was most desperate. The troops on both sides fought with the most determined courage, and I doubt not the conflict at this point was one of the most bloody of the whole war.

Having myself received a wound which disabled me I was forced to leave the field before the struggle terminated. For the details, and an account of the last of the battle, I must refer you to the reports of the brigade commanders.

General Doubleday exhibited the greatest gallantry in leading on his brigade under a terrible fire on the night of the 29th, and, with his aide-de-camp, Major U. Doubleday, and Captain E. P. Halstead, assistant adjutant-general, did much by reckless daring toward keeping this brigade from giving way when hard pressed.

Captain Robert Chandler, assistant adjutant-general (King's staff), and Captain J. A. Judson, assistant adjutant-general (who was taken prisoner while bearing an order on the field), were distinguished for their good conduct on the 29th.

Lieutenant Bartlett, aide-de-camp to General King, behaved with the greatest coolness, and rendered efficient service on the 30th, bearing orders under a heavy fire.

Lieutenant James Lyon, aide-de-camp, both on the 29th and 30th of August, bore himself in the most gallant manner, and deserves, as he receives my most heartfelt thanks.

Very respectfully, your obedient servant,,

JNO. P. HATCH,

Brigadier-General Volunteers.

Captain R. CHANDLER, Assistant Adjutant-General.