I regret the necessity of having to announce the fact that during the ferrying of my command to Bruinsburg a collision occurred between the steamboats Horizon and Moderator, in which the former sunk with Battery G, SECOND Illinois Light Artillery, Captain Sparrestrom commanding, on board, which was entirely lost, except a small number of horses. The men were all saved except two, who were drowned.

You will observe that worst kind of roads, the axles of the batteries and wagons often scraping the ground. During the march, roads and bridges were constructed, under the direction of S. R. Tresilian, DIVISION engineer of my staff, who exhibited a great deal of energy and dispatch.

I crossed the river in person on May 1, and hastened forward to the head of the two brigades which had crossed the evening previous, and had been ordered by General Grant to move forward on the road to Port Gibson early on that morning to the support of General McClernand, who was supposed to be engaging the enemy at or near that place. I directed my assistant adjutant-general to remain at Bruinsburg and come forward with the SECOND Brigade as soon as it should have crossed the river.

I arrived with the First and THIRD Brigades at Thompson's Hill (where General McClernand's corps was engaging the enemy) at or near 12 m., and was directed to immediately form General Smith's (First) brigade on the left and General Stevenson's (THIRD) brigade on the right of General McClernand's command. General Smith immediately formed his brigade on the left of General Osterhaus, who was being closely pressed by a heavy force of the enemy advantageously posted. The brigade was formed in two lines, the Twentieth and Thirty-first Illinois and Twenty-THIRD Indiana Infantry, commanded by Lieutenant-Colonel Richards, Colonel McCook, and Lieutenant-Colonel Davis, respectively, constituting the first or advanced line, and the Forty-FIFTH and One hundred and Twenty-fourth Illinois Infantry, Colonel Maltby and [Colonel Thomas J. Sloan?] commanding, respectively, forming the SECOND or reserve line, 200 yards in the rear.

The Twenty-THIRD Indiana was ordered to advance as skirmishers in the face of the enemy, and after a severe fire, in which the entire advance line participated, succeeded in dislodging him from his position in front of the brigade. A still farther advance of the brigade in line pressed the enemy back upon a hill, when he essayed a formidable stand. To dislodge him from the position, General Smith caused his command to charge upon his entire front. Led by their gallant commander, the charge was executed with a zeal and heroism that adds another laurel to those already won by the many glorious achievements on the bloody fields of Belmont, Donelson, and Shiloh. They drove the enemy in wild disorder from the field, causing his total rout, and compelling him to leave his dead and wounded in our possession. In this engagement the First Brigade captured on piece of artillery and a number of prisoners.

The THIRD Brigade, General Stevenson commanding, consisting of the Eighth and Eighty-first Illinois, Seventh Missouri, and

Thirty-SECOND Ohio Infantry, commanded by Colonels Post and Dollins, Major Wakefield, and Colonel Potts, respectively, was ordered to the left, as I before stated where it was formed to support General Burbridge, of the Thirteenth Army Corps. The line, when thus formed, filled a vacancy in General McClernand's line. The enemy in front of this brigade was in strong force. The Eighth Illinois Infantry was ordered to support the Eighth Michigan Battery, which opened a destructive fire of shell