On this day, the division of General Richardson, with the exception of a few cavalry, was in advance of the entire Union army. The other corps, except Franklin’s, followed towards the middle of the day. General Richardson came up with the enemy about three miles from Keedysville. The Confederates were posted on a number of wooded hills, little less than a mile from and on the southwest side of Antietam Creek; their lines extended across the Sharpsburg Road, their right resting on a creek only a mile from the Potomac River. General Richardson did not cross the creek, but took up a position on the easterly side. About three o’clock in the afternoon, other portions of the army came up; Pettit’s battery took ground on the hill where the Twenty-ninth was stationed, and shortly after, the battery was joined by two pieces of flying artillery, when matters became lively at once. The enemy had been amusing himself for some hours before, by shelling our unprotected lines. Our artillery at once answered his fire, Pettit’s battery especially making some most excellent shots, in one instance driving the Confederate gunners from their pieces. This artillery duel continued nearly the whole day; and at one time, towards the close, the division, in changing its position, became badly exposed to the enemy’s fire, but fortunately few lives were lost.
On the morning of the 16th, our army was well up towards the creek, with well-formed lines. Pettit’s battery was relieved in the forenoon by another of twelve 20-pounder Parrotts; and these our Brigade supported all day. The enemy had almost exact range of our position, but his shell not exploding, did little execution. There was, however, some loss, and Corporal Tribou of Company C (Twenty-ninth), who carried the State colors, was severely wounded, losing his left foot above the ankle.
While the exact nature of the situation was not known to any except the officers of high rank, yet, when the day closed, there was probably not a private soldier along the line who did not realize that the army was on the eve of one of the greatest battles of the war.
On the 17th of September, which was one of the many beautiful days of the early Southern autumn, was fought the renowned battle of Antietam. The preceding night had been devoted to watching, manœuvring, and careful preparation by the commanders of both armies. Generals Hooker and Mansfield had crossed the creek with their respective corps during the night, bivouacking on the farm of J. Poffenberger, in the vicinity of the enemy’s left;[34] and at daylight on the 17th, these troops became hotly engaged. While the battle was in progress, General Sumner’s corps was ordered to fill a gap on the left of the Union army, where, up to that time, there had been no fighting.
At nine o’clock, General Richardson’s division received its order to march. Moving from the position it had occupied during the night of the 16th, the Irish Brigade again in advance, the division made a wide detour to the right, and forded the creek, the men entering the cold water to their hips. General Richardson, with his staff about him, sat on his horse near the creek; and as the various regiments filed past him, addressed the Colonels in his usual stern manner: “No straggling to-day, Colonel! Keep your men well up and in hand.” When the troops reached the opposite shore of the stream, they were halted for a few moments, the men seizing upon the chance to empty their shoes, wring their stockings, and adjust their equipments. A flock of sheep quietly grazing on the hillside gave the place an air of peace, and but for the loud peal of artillery on the right, the men would have scarcely imagined themselves amid scenes of war.
Now came the second order to march. The ground was ascending, and the Brigade moved by the flank, the Sixty-ninth in advance, and next to them the Twenty-ninth. No sooner had the troops begun to move, than the enemy opened upon them, from the vicinity of Dr. Piper’s and Roulette’s houses, a galling artillery fire.
The crest of the hill was soon reached. The order was here given for the Brigade to form “a line of battle, and move forward till they met the enemy.” Under a terrible fire, the Brigade formed its line with great rapidity and in fine style, in the following order: Sixty-ninth on the right; next the Twenty-ninth; on their left the Sixty-third; and on the extreme left the Eighty-eighth. About this time, General Meagher was disabled, “his horse having been shot under him.”[35]
In front of the line was an open field, over which the enemy’s shot and shell came bounding and crashing incessantly, making great gaps in our line, and strewing the ground with the dead and wounded. “Forward!”—a welcome order; and the Brigade moved rapidly over the field. The enemy increased his fire, but the line moved on. A hundred yards in front was a Virginia fence; on the other side was another field and slightly rising ground; over the crest of the rising ground, a sunken road; and on the farther side of the road, an extensive corn-field and orchard. As the regiments neared the fence, a yell went up from the corn-field, and instantly springing to their feet, a long line of the enemy ran out towards our men, crossing the road and mounting the crest, where they delivered a mighty volley with deliberate aim. In an instant the air seemed filled with hissing bullets and large splinters from the fence.
Our line wavered a little; the fire was frightfully destructive. The field-officers perceiving this, ran through the ranks to the front. Instantly the line stiffened. And now for the fence. “Tear it down!” Immediately two thousand strong hands seize it, and it is flat upon the ground. “Forward!” Everything moves like clock-work. Without firing a shot, the Brigade moved in perfect line toward the sunken road, the enemy all the while firing deadly volleys. “Look at the perfect line of the Irish Brigade as it moves on the enemy!” said General McClellan to his generals, as he sat on his horse, near the creek. “Yes,” says the brave old General Mansfield, who was present and watching the movement with intense interest. “I claim the credit of having drilled the Twenty-ninth Massachusetts Regiment of that Brigade.”
Two-thirds of the distance across this bloody field was performed before came the order to “halt!” and at the same time the command to “fire!” The volley that played out along the line towards that terrible crest made the hills ring far and wide. It was spitefully done, and very effective, for instantly the Confederates fell back from the summit into the sunken road, receiving as they did several other volleys. No sooner in the road, the enemy, nothing daunted, commenced to fire over the bank. That part of our line held by the Sixty-ninth and Sixty-third was much exposed, while the Twenty-ninth, its usual “good luck” not forsaking it even here, was protected by a little ridge in its front and a slight depression of the ground upon which it stood. This did not in any way affect their range on the enemy,—the corn-field opened wide before them, their shots cutting off the stalks of green corn as would a scythe, and having their effect upon the enemy who were hiding there.