P. S. - I take great pleasure in calling special attention to the conduct of Private William Lawrence, of Company I, Sixth Wisconsin, whose coolness and bravery under fire fell under my personal observation on the 30th.

HEADQUARTERS GIBBON'S BRIGADE.

Camp near Upton's Hill, Va., September 3, 1862.

SIR: I have the honor to submit the following report of the operations of my brigade during the action of the 30th of August:

The division was placed under the orders of Major General Fitz John Porter to aid in the pursuit of the enemy, who was supposed to be retreating on the Warrenton turnpike. The brigade was formed in two lines, and entered the woods on the right of the turnpike in rear of Patrick's. My rear line was afterwards moved to the right by order of General Porter, and the whole brigade moved forward in one line, the Sixth Wisconsin on the right, then the Nineteenth Indiana, and the Second and Seventh Wisconsin consolidated on the left.

Fire was soon after opened by the enemy, and the fight continued actively until we were ordered to retire, which we did slowly and in good order. The wood being thick, communication between the different commands was difficult. My regiments got separated. Some doubt appeared to exist as to whether the order to retire had been given, and while waiting for its reception all the rest of the troops retired, followed by the enemy, and when I got out with the Sixth Wisconsin none of our own troops were in the vicinity. Captain J. N. Mason, my quartermaster, while gallantly making an examination to ascertain the presence of the enemy on our left and rear, was wounded by their skirmishers. After leaving the woods the brigade was formed to support Gibbon's and another battery engaged in repelling an attack on our left and center. It behaved here with its usual gallantry, although subjected to a severe cross-fire of both infantry and artillery, and successfully beat back the advance of the enemy. It retired in excellent order on my receiving direction to that effect from Major-General Hooker.

The commanding officers, Colonel Meredith, Nineteenth Indiana; Lieutenant-Colonel Fairchild, Second Wisconsin, commanding Second and Seventh Wisconsin consolidated; Lieutenant-Colonel Bragg, Sixth Wisconsin, and Captain J. B. Campbell, commanding Gibbon's battery, by their prompt and energetic execution of my orders merit the highest commendation, while the steadiness and discipline of the officers and men were most admirable, and I have great cause to be proud of the brigade I have the honor to command.

The brigade was detailed by General McDowell to act as rear guard during the retreat, and they were in consequence the last troops to leave the field. The coolness and efficiency of fire exhibited by Gibbon's battery under its gallant commander were the admiration of all, and the battery did most excellent service throughout the day.

I am, sir, very respectfully, your obedient servant,
JOHN GIBBON,

Brigadier-General, Commanding Brigade.

Captain R. CHANDLER,

Assistant Adjutant-General, King's Division.

P. S. - The total loss by the brigade during the action was 16 killed, 68 wounded, 36 missing. Total, 120.