Numbers 165. Report of Captain Clermont L. Best, Fourth U. S. Artillery, Chief of Artillery of the battle of Antietam.

HEADQUARTERS ARTILLERY, BANKS' CORPS,
September 22, 1862.

LIEUTENANT: I have the honor to forward herewith briefly, but fully as needs be, the operations of the artillery of the Twelfth Corps in the engagement of the 17th near Sharpsburg:

At 2 a. m. on the morning of the 17th, the corps being then near the battle-ground, I was ordered by General mansfield to proceed in person to the rear to post two batteries of the corps on some hills adjacent to the headquarters of General McClellan, to be pointed out by a staff officer. After performing this service, posting the Fourth Maine Battery and the Sixth Maine Battery, I proceeded to the field, and found that General Mansfield and General Williams, succeeding him, had already posted the riffled batteries of Knap and Cothran in front of the infantry and near the enemy. Captain Knap commenced fire at 7 a. m. slowly and deliberately, the enemy advancing him several times be tween that and 12 m., but each time repulsed with canister. At 12 m. one section of his battery, under Lieutenant McGill, was ordered by General Greene forward to assist Colonel Tyndale in holding a wood. Colonel Tyndale ordered one piece of this section to enter the wood, in that act of which it was met with such a destructive fire from the enemy, wounding 4 cannoneers and killing 3 horses, that the piece had to be abandoned, and was lost. Captain Knap continued working the remaining five guns till 3 p. m. at which time he withdrew from the field, wanting ammunition.

Captain cothran was assigned a position near the center of the line of the line of battle, supported by the One hundred and seventh New York Volunteers, and was exposed to the enemy's fire from 9 a. m. till 3 p. m., using, at times, canister rapidly. He also withdrew, out of ammunition. Captain Hampton's battery was placed in position near the Dunkard Church and expended 217 rounds against the woods in which said church is located.

The respective captains named speak in confident terms of the gallantry of their officers and men during the varied fortunes of that day. The gallantry of the captains themselves has been established on this as well as on previous fields.

Captain Knap brought from the field on the 19th one iron 12-pounder howitzer and caisson abandoned by the enemy.

Respectfully, yours,

C. L. BEST,

Captain and Chief of Artillery, Banks' Corps.

S. E. PITTMAN,

First Lieutenant and Acting Assistant Adjutant-General.

Numbers 166. Report of Captain George W. Cothran, Battery, M First New York Light Artillery, of the battle of Antietam.

Near Keedysville, Md., September 18, 1862.

CAPTAIN: About 9 a. m., on the 17th instant, I was ordered to proceed