Second Brigade.- Colonel J. F. Farnsworth, Eighth Illinois, commanding; Capts. W. H. Medill, E. S. Kelley, Alpheus Clark, E. J. Farnsworth, J. D. Ludlam; First Lieutenant D. J. Hynes, Adjt. Daniel W. Buck, Second Lieutenant I. W. Trask, of the Eighth Illinois Regiment. Third Indiana Cavalry, Major Chapman; Captains Patton and Lemmon. Eighth Pennsylvania Cavalry, Captain Peter Keenan. First Massachusetts Cavalry, Captain Crowninshield.

Third Brigade.- Colonel R. H. Rush commanding; Lieutenant Colonel C. Ross Smith, Sixth Pennsylvania Lancers. Fourth Pennsylvania Cavalry, Colonel J. H. Childs (who was killed); Lieutenant Colonel J. K. Kerr.

Fourth Brigade.- Colonel A. T. McReynolds commanding, First New York Cavalry; Major Adams, First New York Cavalry; Major J. A. Congdon, Twelfth Pennsylvania Cavalry.

Fifth Brigade.- Two regiments of which were engaged in the battle of Antietam, under Colonel Davis; Eighth New York, Colonel B. F. Davis; Third Pennsylvania, Lieutenant-Colonel Owen commanding.

A portion of the First Regular Cavalry were under my command in the pursuit of the enemy to the river, and did good service under Captain Marcus A. Reno.

To the following officers of my staff I am much indebted for their efficient and valuable services: Captain A. J. Cohen, assistant adjutant-general; First Lieuts. Isaac M. Ward, Sixth Cavalry, and C. Thompson, First New York Cavalry, aides-de-camp; First Lieutenant J. W. Spangler, Sixth Cavalry, division quartermaster; First Lieutenant J. A. Hall, First Cavalry, division commissary of subsistence. Also to First Lieutenant Leroy S. Elbert, Third Cavalry, acting aide-de-camp.

The five small battalions of regular infantry from Sykes's division on the 17th at the battle of Antietam kept a superior force from my guns for the greater part of the day. These men behaved splendidly throughout the fight, and Captain Hiram Dryer, of the Fourth Infantry, who was in command, distinguished himself by his gallantry and good service. This command was composed of a battalion from each of the following regular regiments, viz: The Second, Fourth, Tenth, Twelfth, and Fourteenth Infantry.

To the Signal Corps and to the members of the special service I have been indebted for important information furnished at various times.

I am, general, very respectfully, your obedient servant,

A. PLEASONTON,

Brigadier-General, Commanding Division.

Brigadier General R. B. MARCY,

Chief of Staff, Army of the Potomac.

No. 9. Reports of Major Joseph Hooker, U. S. Army, commanding First Army Corps, of the battles of South Mountain and Antietam, with congratulations of General McClellan.

HEADQUARTERS FIRST ARMY CORPS,
Washington City, D. C., November 7, 1862.

COLONEL: I have the honor to report that the First Corps commenced its march from the camp on the Monocacy at daylight on the morning of the 14th September, and continued it over the National