HEADQUARTERS BATTALION OF REGULARS, Camp Turnbull, Va., July 24, 1861.

CAPTAIN: In compliance with your circular of the 23rd instant, I have the honor to report the following casualties that occurred in my command during the recent battle before Manassas: Three commissioned officers wounded; one assistant surgeon missing; 13 rank and file killed, 17 wounded, 12 of whom are missing; 42 missing. A list is inclosed.* Many of the latter are supposed to have taken the Alexandria road by mistake and will no doubt rejoin their colors to-day.

This battalion, composed of two companies of Second U. S. Infantry, five companies of the Third U. S. Infantry, and one company of the Eighth Infantry, left its camp near Centreville about 3.30 a.m. on the 21st instant, and after a circuitous march of ten or twelve miles arrived on the enemy's left, and was immediately ordered to support the force under Colonel Burnside, which was suffering from a severe fire in its front. Our line was rapidly formed, opening fire, and a column under Colonel Heintzelman appearing at the same moment on our left, the enemy fell back to the rising ground in his rear. My battalion was then advanced to the front, and took a position on the edge of a wood immediately opposite a masked battery and a large force of the secessionists posted about aa house and the fences and trees around it. My three left companies were deployed as skirmishers under Captain Dodge, Eighth Infantry, and did great execution among their ranks. At this time the whole battalion became actively engaged, and a Rhode Island battery coming into action on my right, and having no support, at the request of its commanding officer, and seeing myself the necessity of the case, I remained as a protection to his guns. For more than an hour the command was here exposed to a concentrated fire from the batteries and regiments of the enemy, which seemed doubled when the guns of the Rhode Islanders opened. Many of my men assisted in working the latter battery.

As the attack of our Army became more developed on the right, and the necessity for my staying with the guns ceased, I moved my battalion in that direction, passing through crowds of retiring troops, whom we endeavored in vain to rally. Taking a position on the extreme right, in front of several regiments of the enemy, I opened an effective fire upon them, and held my ground until all our troops had fallen back and my flank was turned by a large force of horse and foot. I then retired a short distance in good order, and facing to the enemy on the crest of a hill, held his cavalry in check, which still threatened our flank.

At this stage of the action, my command was the only opposing force to the enemy, and the last to leave the field. By taking advantage of woods and broken ground, I brought it off without loss, although the guns of our opponents were playing on our line of march from every height. While thus retiring, I received an order from the brigade commander to cover the retreat of that portion of the Army near me, which I did as well as I was able, remaining in rear until all of it had passed me.

After crossing Bull Run my command was threatened by a large force of cavalry, but its order and the regularity of its march forbade

any attack. We reached our camp beyond Centreville at 8 p.m. It is but proper to mention that our officers and men were on their feet from 10 p.m. on the 20th until 10 a.m. on the 22nd. Without rest, many without food, foot-sore, and greatly exhausted, they yet bore the retreat cheerfully, and set an example of constancy and discipline worthy of older and more experienced soldiers. My officers, nearly all of them just from civil life and the Military Academy, were eager and zealous, and to their efforts is due the soldierly retreat and safety of the battalion, as well as of many straggling volunteers who accompanied my command. The acting major, Captain N. H. Davis, Second Infantry, rendered essential service by his coolness, zeal, and activity. Captain Dodge, Eighth Infantry, commanding the skirmishers on the left, was equally efficient, and to those gentlemen and all my officers I am indebted for cordial co-operation in all the movements of the day. Lieutenant Kent, although wounded, endeavored to retain command of his company, but a second wound forced him to give it up. He and Lieutenant Dickinson, acting adjutant, wounded, and Dr. Sternberg, U. S. Army, are believed to be in the hands of the enemy.

I beg to call the attention of the brigade commander to the services of Sergeant-Major Devoe, of the Third Infantry, who was conspicuous for his good conduct on the field. The arms and equipments of my command are in good condition, but the men are destitute of blankets, and in want of necessary clothing.

Very respectfully, your obedient servant,

GEORGE SYKES,

Major, Fourteenth Infantry, Commanding Battalion of U. S. Marines.