The artillery of the corps was redistributed to correspond with the new organization, and the cavalry was concentrated at Baton Rouge, Plaquemine, Thibodeaux, and New Orleans, with orders that all details for orderly duty and the like were to be furnished from a single battalion, the 14th New York, attached to the defences of New Orleans.
Weitzel's division, except his old brigade under Merritt, took post at Baton Rouge, where also Emory's division was encamped, successively commanded by Nickerson and McMillan, while Grover's division, assigned to the defence of New Orleans, was separated, Birge occupying La Fourche, with headquarters at Thibodeaux, and Cahill forming the garrison of New Orleans.
At Port Hudson, after the departure of the nine-months' troops, Andrews had the 6th Michigan newly converted into the 1st Michigan heavy artillery, ten troops of the 3d Massachusetts cavalry, Rawles's, Holcomb's, and Barnes's batteries; and besides these the infantry of the Corps d'Afrique, then in process of organization, including, at the end of August, the old 1st and 3d regiments and the five regiments of Ullmann's brigade--the 6th to the 10th. The return of the post for the 31st of August accounts for an effective force of 5,427; of these 1,815 belonged to the white troops and 3,612 to the colored regiments. The whole number of infantry regiments of the Corps d'Afrique, then authorized, was nineteen, of which only the first four were completed. Besides these there were two regiments of engineers, the 1st full, the 2d about half full, and three companies of heavy artillery, making the whole muster of colored troops in the department about 10,000. Towards the end of September the regiments of infantry numbered twenty, with ranks fairly filled. The Corps d'Afrique was then organized in two divisions of two brigades each, Ullmann commanding the First division and the senior colonel the Second. Rawles's battery was assigned to the First division and Holcomb's to the Second. This division, however, never became much more than a skeleton, its First brigade being from the first detached by regiments for garrison duty in the various fortifications.
Andrews at once took up the work of organization and instruction in earnest, rightly conceiving it not merely possible, but even essential, to give to the officers and men of the colored regiments, thus formed into an army corps under his command, a degree of instruction, as well in tactics as in the details of a soldier's duty, higher then was to be found in any save a few picked regiments of the volunteer and regular service. The prejudice at first entertained against the bare idea of service with colored troops had not entirely disappeared, yet it had so far lost its edge that it was now possible to select from a number of applicants for promotion, especially to the higher grades, officers who had already shown their fitness and their capacity, while holding inferior commissions or serving in the ranks of the white regiments. Thus the original source of weakness in the composition of the first three regiments was avoided, and, small politics and local influence being of course absent, and Banks's instructions being urgent to choose only the best men, the colored regiments soon had a fine corps of officers. To the work now before him Andrews brought an equipment and a training such as few officers possessed. Experience had shown him the merit, the capacity, and the defects of the American volunteer officer. At the very bottom of these defects was the looseness of his early instruction in the elements of his duty; once wrongly taught by an instructor, himself careless or ignorant, he was likely to go on conscientiously making the same mistake to the end of his term. Realizing his opportunity, Andrews set about establishing uniformity in all details of drill and duty by establishing a school of officers. These he himself taught with the greatest pains and industry, correcting the slovenly, yet encouraging the willing, until the whole corps was brought up to a uniform standard, and on the whole a high one.