at $30 per man as the maximum, but a part of this expenditure for transportation has already been incurred.
BENJ. F. BUTLER,
OFFICE CHIEF ENGINEER ARMY OF THE POTOMAC,
Washington, February 7, 1862.
Colonel A. V. COLBURN,
COLONEL: I do not know how General Butler proposes to operate. The memorandum I drew up was made for the used of Mr. Fox, and without consultation with others. It proposed to attack New Orleans and obtain command of the Mississippi River by a combined naval and land [force], operating through the months of the river, and making the capture of Forts Jackson and Saint Philip an essential feature of the plan.
I believe that any other way of approaching New Orleans is to run great risk and half do the work, and, under the most favorable issue, to protract the period of complete triumph of our arms in the Mississippi Valley. Take these works, and New Orleans falls, and our gunboats appear at once before Vicksburg, Nathcez, and Memphis, and the rebel defense both ways (our armies and flotilla in the Upper Mississippi cooperating) is completely annihilated. The approaches to New Orleans by Lakes Borgne and Pontchartrain are very intricate; require the expeditionary force to be put in boats or barges and towed for 15 or 20 miles; then to attack works not easily taken; then to encounter the hazards of a defile through narrow bayous and over narrow causeways, &c.
Assuming the attack by the Mississippi adopted, I thought 10,000 men to be more than would be required for the capture of those works, in which I depended mainly upon a coup distant of the Navy, that it would be enough for the immediate capture (aided by the fleet) of New Orleans, and therefore that it would not be best to encumber the expedition with a larger mass of transports than number of troops required, but that 20,000 men should be available in all, the balance being left, say, at Ship Island, to be brought up immediately or as soon as necessary. I thought a dozen siege 24-pounders enough; even this perhaps is excessive; for if the works fall at all they will fall at once, or they will be reduced more slowly by naval bombardment and cutting off of provisions and supplies. I should think the forces estimated in the "Memoranda of changes in General Butler's suggestions" * to come pretty near the mark, and that the cavalry, artillery, troops, and light batteries were sufficient. I look upon this expedition as one of immense importance. Its failure would be a terrible blow; its success would bring us almost to the close of the war. Hence I recommended in my memorandum that the Chief Engineer United States Army should be consulted on account of his thorough knowledge of the works and his great experience in such matters.
I am, very respectfully, your most obedient servant,
J. G. BARNARD,
Brigadier-General, and Chief Engineer.
* See pp. 687, 688.