Battle of Antietam
The batter was commanded by First Lieutenant Evan Thomas, and brought six Napoleons to the field. From Lieutenant Thomas' official report:
"On the 17th of September, 1862, I received orders to move to the front. I was halted in the woods the enemy had been driven out of that morning, and the right section was ordered into position. The rest of the battery was soon ordered into position, the same occupied by Lieutenant Kirby's battery, and joined the right section there. I remained there without firing a shot until our left was driven back. I then changed front to fire to the left, and opened an the advancing enemy with spherical case, and then, as they approached nearer, with canister. They came on, and I would undoubtedly have lost my battery had not Franklin's column come up at that time. I then changed to my original front, and opened with solid shot on a battery to my right, in the opposite woods, which was soon silenced. Another battery opened on me, which I saw was out of my range. A rifled battery coming up at that time, and seeing I could do no good and was only losing horses for nothing, I deemed it prudent to withdraw. I was shortly afterward ordered to the rear, to fill up, where I staid until ordered to my division. All the orders that I received were from Captain Clarke, chief of artillery, Sumner's Corps.
All my officers and men behaved with great coolness and bravery. Several of Baxter's Zouaves [72nd PA] helped me considerably in carrying ammunition. One was killed and one wounded. I would state that I had no infantry support during the whole engagement."
OFFICIAL RECORDS: Series 1, Vol 19, Part 1 (Antietam - Serial 27), Page 284
From the marker at Antietam:
"Batteries A and C (consolidated), 4th U.S. Artillery (6 guns) relieved Battery I, 4th U.S. Artillery just north of this point and went into position, the left of the Battery resting on this road, where it remained inactive until Greene's Division, Twelfth Corps, was driven from the woods around the Dunkard Church, when the Battery changed front to the left, opening fire with spherical case and canister upon the charging Confederates, who, by the aid of Irwin's Brigade and two Regiments of Hancock's of the Sixth Corps, were repulsed. The Battery then resumed its original front and opened with solid shot upon the Confederate Artillery in the woods around and north of the Dunkard Church. Late in the day it was relieved and moved to the high ground occupied by Richardson's Division in its assault upon the Confederates in the Sunken Lane and Piper's Cornfield, where it remained until the morning of the 18th. "