When this state of affairs was made known to Major Van Dorn of the Confederate Army, he organized an expedition to capture the post. It was composed of about 5000 men under Gen. J. C. Breckenridge who expected to be aided in his endeavor by the ram Arkansas. With his entire force moving along the two roads that enter Baton Rouge from the southwest he made a vigorous attack in the early morning of August 5. Williams was expecting the attack (we read in the diary of one of the men that the horses had been standing in harness three days and three nights), and had arranged his forces to meet it. His army, depleted as it was by sickness, numbered only 2500 effective men. He posted the 4th Wisconsin on Bayou Gros on the extreme left, with a portion of Manning's Battery in the arsenal grounds on its left. On the right of that regiment was the 9th Connecticut with four of Manning's guns in the cemetery. To the left of Greenwell Springs Road was the 14th Maine and next came the 21st Indiana with four guns of Everett's Battery. The 6th Michigan was posted across the country road with two guns. In the rear of the last two was the 7th Vermont, and at the extreme right was the 30th Massachusetts supporting Nims' Battery.[[3]]
Owing to the illness of Captain Nims, First Lieutenant Trull was in command, while to take the place of the men in the hospital a detail of thirty men had been secured from the 9th Connecticut so that when the battle opened the six guns were manned.
The conflict lasted from four to nine o'clock, a period of five hours, and throughout the entire battle Nims' Battery won the highest commendation for efficient service. Perhaps nothing could give a better account of what it accomplished than the Official Report of Colonel Dudley:[[4]] "I immediately ordered Nims' Battery under the command of the brave and efficient First Lieutenant Trull, to the left and considerably to the front so as to clear the thick woods in its front. This battery went into action within 250 yards of a Kentucky regiment sheltered by a fence and a cornfield, where it remained doing excellent service until ordered to change position. Officers and men could not have behaved better. More coolness could not have been expected from veterans than the officers and men of this battery displayed. They changed position four times under my own observation and on each occasion the gallant commander displayed his competency for the prominent part he acted in this severest part of the field.... At one time the undaunted Trull with his battery was hotly engaged on the right with a full battery of the enemy which had approached within 150 yards (supposed to have been the celebrated Simmes' Battery), but the 6th Michigan moved up to the support of Nims' Battery in elegant order. Its assistance came most fortunately for it was clear the enemy intended to outflank us at this point.... At this juncture of the conflict I ordered Lieutenant Trull to fire his three left pieces across the fronts of the Indiana 21st, Massachusetts 30th, and 7th Vermont. This was the turning point of the right wing. The galling fire of canister effectually silenced the enemy's fire and they retreated to the rear."
At one time the guns became so hot that it was impossible to use them and it became necessary to wait. While water was being brought to cool them a fierce attack was made by the enemy, but proved unsuccessful.
"At another time the enemy advanced bearing the Stars and Stripes until they were within 25 yards of the battery who supposed them to be their own men, but soon their artillery and infantry opened a tremendous fire, too high, however, to do much damage. In an instant the guns were discharged and the enemy mowed down like grass, the first fire killing over 100. Great cheers and praises for Nims' boys could be heard all over the battlefield." Diary of J. S. Knowlton.
A correspondent of the Boston Journal gives the following description of the battle.
"Two highways run out of Baton Rouge—one above and one below,—on each side of the town; about a mile and a half a road cuts these two roads at right angles, while extending from road to road is a large cemetery, facing towards the city and looking directly into the camps of the Indiana, Massachusetts, and Connecticut regiments. The front of this cemetery is fenced with paling, while the cemetery is thickly strewn with large tombs and overgrown with high rank weeds. This was the position of the rebel center. Our center was composed of the Indiana 21st, the Massachusetts and Connecticut, drawn up on the opposite side of the roads, and not more than forty-five rods distant. The rebel right approached through corn-fields and over a rolling country, attacked with great impetuosity the 14th Maine's camp and drove them out, burning and pillaging the camp in a few minutes. The 14th Maine rallied, and, supported by the Massachusetts and Nims' Battery, returned to the attack and drove the enemy back with great slaughter.
"The fiercest part of the conflict, at this tide of the battle, occurred before and within a house which the rebels obstinately determined to get possession of. The most conspicuous of the rebels at this place was a huge negro, armed and equipped with musket, knapsack and uniform; he led the rebels, and met his death at the hands of one of our men. Pressed back by our left, and our ground regained, the battle raged in front with desperate fierceness. So silently did the rebels approach, and so well were they concealed, that they were in the cemetery and drawn up in battle array without our knowing it. With a yell they rushed up to the fence, dashed through it and across the road, bearing everything before them. At one time the opposing forces were hand to hand, and our handful of men were driven out of their camps and back into the town; but, rallied on every hand by their officers, and the cool daring of General Williams, assisted by the gunboats that began to fire shell on each bank with perfect accuracy and deadly effect, our troops bravely rushed to the front and drove the entire rebel center, back across the road, into and beyond the cemetery, from which they were not again able to emerge."
From a description of the battle given by a soldier who was in the fight, we extract the following:
"The 14th Maine, 21st Indiana and 6th Wisconsin were the first regiments engaged. They held in check about eight thousand Confederates for about one hour, when they were forced back a quarter of a mile, the Confederates occupying their camps, which they destroyed. On account of a heavy fog, the 7th Vermont, 9th Connecticut and 4th Wisconsin were not able to ascertain the exact position of the enemy, and were of but very little service until the new line was formed. Captain Nims[[5]], Captain Everett, and the battery on the right, and two pieces of the 4th Massachusetts on the extreme left, opened a murderous fire from their batteries, which was returned with spirit by the Confederates. The battle raged without a moment's intermission, and with great severity for two hours. During this time nothing but a continual roar of artillery, the rattle of musketry, the shouts of the combatants and the groans of the wounded and dying was to be heard. Captain Nims' Battery was compelled to fall back, his guns being so hot it was impossible to use them.