Of all these rivers there is none which will not answer the purposes of commerce, at least to a very considerable extent; and as they join the Mississippi above New Orleans, it is evident that this city may be considered as the general mart of the whole. Whatever nation, therefore, chances to possess this place, possesses in reality the command of a greater extent of country than is included within the boundary-line of the whole United States since from every direction are goods, the produce of East, West, North, and South America, sent down by the Mississippi to the Gulf. But were New Orleans properly supplied with fortifications, it is evident that no vessels could pass without the leave of its governor; and therefore is it that I consider that city as of greater importance to the American government than any other within the compass of their territories.
Having said so much on its commercial advantages, let me now point out more distinctly than I have yet done the causes which contribute to its safety from all hostile attempts. The first of these is the shallowness of the river at its mouth, and the extreme rapidity of the current. After flowing on in one prodigious sheet of water, varying in depth from one hundred to thirty fathoms, the Mississippi, previous to its joining the Mexican Gulf, divides into four or five mouths, the most considerable of which is encumbered by a sandbank continually liable to shift. Over this bank no vessel drawing above seventeen feet water can pass; when once across, however, there is no longer a difficulty in being floated; but to anchor is hazardous, on account of the huge logs which are constantly carried down the stream. Should one of these strike the bow of the ship, it would probably dash her to pieces; whilst, independent of this, there is always danger of drifting or losing anchors, owing to the number of sunken logs which the under-current bears along within a few feet of the bottom. All vessels ascending the river are accordingly obliged, if the wind be foul, to make fast to the trees upon the banks; because without a breeze at once fair and powerful, it is impossible to stem the torrent.
But besides this natural obstacle to invasion, the mouth of the river is defended by a fort, which from its situation may be pronounced impregnable. It is built upon an artificial causeway, and is surrounded on all sides by swamps totally impervious, which extend on both sides of the river to a place called the Detour des Anglais, within twenty miles of the city. Here two other forts are erected, one on each bank. Like that at the river’s mouth, these are surrounded by a marsh, a single narrow path conducting from the commencement of firm ground to the gates of each. If, therefore, an enemy should contrive to pass both the bar and the first fort, he must here be stopped, because all landing is prevented by the nature of the soil; and however fair his breeze may have hitherto been, it will not now assist his further progress. At this point the Mississippi winds almost in a circle, insomuch that vessels which arrive are necessitated to make fast till a change of wind occur.