It may be remarked too that the permanent magazines of the work and external batteries (the only masonry and bomb-proof buildings there are) would not hold more than 700 or 800 barrels of powder stowed in bulk (not much over 100 rounds for the supposed armament); that there are no filling rooms, &c.; that there were no other storerooms for provisions or other stores than the wooden building mentioned.
I can conceive it, therefore, possible that the garrison might surrender merely form the effects of the cannonade, accompanied with preparations for landing and assault..
Should it not do so the landing must be made, and we may rely upon the investment and continued cannonade or we may assault.
A light field gun would destroy the draw-bridge and gates on the southwest front, and ten, skirmishers being advanced to keep down any fire the parapets, a few planks thrown over the draw-bridge gap would complete a bridge.
In previous pages I stated that the ditches had 6 feet of water in them; so they had, but I am told by Lieutenant Weitzel that they have since filled up very much; that there is not more than 4 feet now.
They are narrow, varying from 30 to 40 feet. A few guns from land batteries at a distance will see enough of the walls to bring them down (party filling the ditch), and facines thrown in would do the rest. The fleet, as before said, might breach the river-front walls, &c. Whether the work is taken by one or the other of these means it cannot hold out long.
This work taken, its guns and the batteries, we would speedily establish on the river banks below, would enfilade every barbette battery of Fort Jackson, and breach the curtain and flanks of the two water fronts; our mortar vessels would shower shells upon it, and our fleet and land forces would cut off all supplies. (This work, like Saint Philip, had not magazine room enough for more than 100 rounds of powder in barrels, and it would be difficult to find room in other casemates destroying their efficiency as gun-rooms.)
By one means or another the work must soon surrender, and with its surrender New Orleans and Louisiana fall, the valley of the Mississippi is conquered.
I took up this subject not foreseeing the conclusions it would lead to in my mind. If those conclusions are correct, there is no operation the Government can undertake which promises so important results. And, moreover, these results cannot be fully obtained without this capture.
To reach New Orleans from Saint Louis implies the consequent of the whole valley down, or, in other words, it implies almost the complete triumph of our arms everywhere.
To capture New Orleans from the mouths is, without waiting any such problematical result, to take a great stride toward obtaining complete triumph for our arms.
But to pass these works merely with a fleet and appear before New Orleans is merely a raid, no capture. New Orleans and the river cannot be held until communications are perfectly established. They are more easily and more perfectly established by the mouths of the river than by the lakes.
The avenues from the lakes can only be reached by light craft, and these are mere bayous, through swamps and narrow defiles, along canals easily obstructed, easily defended; and, moreover, these avenues are now all permanently fortified.