the principles upon which they base them. But propositions brought forward by competent persons, who have had long experience in the practice of their profession, ought to be received with less reserve and more confidence. Instances are numerous, in which yearly losses have been permitted to continue, until the aggregate amount has gone a hundred fold beyond the expense that would have been sufficient, in the first instance, to prevent them, and in many cases the remedy has come too late to save. The reluctance of governments to undertake the responsibility of new improvements, has deprived some countries of opportunities of national pre-eminence which time never threw in their way again. Indeed, if a fair estimate could be made, it would be found that the losses consequent upon the refusal to adopt, or the procrastination of new improvements of a public character, have been greater than the actual expense of all that have ever been undertaken, successful or unsuccessful.

The present Defective and Dangerous Condition of the River.-So long as the present condition of the river is permitted to continue, all attempts to remedy the abrasion of its banks, the overflow of its waters, and the damage resulting from them, by mere temporary, or local, improvements-no matter how costly they may be-must prove utterly inefficient. The course of the river must undergo a radical change; and the system of improvement must be of a general, uniform and consistent character, before any real permanent benefit can be derived from the amount of expenditure which the giving way of the levees render yearly necessary. It is, therefore, the duty of the legislature of Louisiana to adopt some such system, as by that means only can they hope to remedy the evils consequent upon the present condition of the river; or relieve the agricultural interests along its banks, from the heavy losses yearly recurring, or save the commercial and real estate interests from the utter ruin that now threatens them. A heavy responsibility must rest upon each future legislature of that state, for every neglect to perform so highly important a duty. That the improvements hitherto attempted have proved insufficient to accomplish the end desired, requires no argument: the results speak for themselves. Till now, if the utterly futile efforts to deepen the southwest pass by dredging machines be excepted, all attempts to improve the river have been limited to a few cut-offs, executed without any regard to system, and not even in the proper direction; and of levees erected along the banks at random, without any regular, uniform, or consistent plan. In fact, the river has been left in its natural state, and entirely to the discretion of the planters along its banks. Consequently, the convex banks have steadily increased, in some cases naturally, in others by artificial means used for that purpose; so that the whole current of the river has been thrown with a yearly increased force against the concave banks, and the tendency to abrasion, change, and overflow, has been yearly increased. This is all that has been done for the river. The result of which has been to increase its already existing defects, while nothing has been attempted in aiding the discharge of the water, so as to reduce its height, or to relieve the levees from its great pressure in time of flood, which is continu

ally wearing them away and breaking through; such as straightening the course of the river, where it could be done by the making of properly directed cut-offs, or altering abrupt curves into those of large radii, or by centralizing the current. The very means used operate against the intended object. To increase the convex banks and the levees, also, building new and raising the old, serves but to increase the resistance to the motion of the waters, and add to their accumulations in time of flood, thus making the damage more certain and wide-spread, should a crevasse occur. The great error has been, that all attempts have been made with a view, or, at least, with the result of raising the waters by impeding their progress; instead of lowering them, by straightening and regulating the bed in which they run.

Conclusions. In thus placing my views before the public, my desire is to confer a benefit upon my fellow-citizens of the state of Louisiana, by presenting for their consideration a mode of improving the Mississippi, consisting of a system for regulating and leveeing the channel, which combines that economy and security so indispensably necessary in works of this kind. It needs no argument to prove that the evils arising from the present condition of the river are yearly increasing; and that the time has come when some general and uniform system for the permanent improvement of the channel throughout the whole lower valley ought to be adopted. For the heavy losses and expenses entailed upon the planters by periodical inundations already surpass, in the aggregate, the cost of any system of improvement that may be adopted, however general or extensive it may be. The cost of constructing the levees, even on their present defective system, is a great obstacle in the way of any general improvement of the river, as it must cause expense, which, with the uncertainty of success in the minds of some, may for a time prevent the adoption of my plan. But I feel confident that the people of Louisiana, when they consider how utterly inefficient their present system has proved, notwithstanding its immense consumption of time, labor, and money; and when they compare it with the system I propose, which is simple, comparatively cheap, and entirely in accordance with the laws of nature, they will be compelled to adopt it, even on the principle of economy, as not only the best, but the only means by which the agricultural interests can be secured from heavy and frequent losses, and their commercial and real estate interests from total ruin.

If this system of improvement be adopted by the legislature, I have no hesitation in declaring my entire confidence that the result will fully establish all that can be claimed for it. Overflows will cease; the channel will become uniform and permanent; its navigation will be secure and uninterrupted in low water as well as in time of a flood; and the agricultural, commercial, and real estate interests along the river banks will no longer be exposed to heavy losses, or threatened danger.

The great size of the lower Mississippi, the extent of territory through which it flows, and the vast and important interests which

have grown into existence upon its borders, and now lie exposed to the ravages of inundations, render it utterly impossible that its power can be controlled, and its defects remedied, through the means of individual energy or individual capital. The improvement of the river must be the work of that government whose people are the most deeply interested in its accomplishment; and upon the legislature of that state must devolve the highly important duty of selecting and adopting the mode in which it shall be carried out. They can no longer neglect this duty in justice to themselves, for many of them are sufferers by the present condition of the river, and personally interested in the matter; nor in justice to the whole state, whose every prosperity is involved in it. For the manner in which they may undertake to discharge this duty, they will incur a heavy responsibility; but should they neglect or refuse it altogether, they will prove themselves to be as blind to the experience of the past as deaf to the warnings of the future.

Mobile, November, 1851.

ART. II.-REMARKS ON THE REPORT OF CHARLES ELLET, JR.,

IN REFERENCE TO THE DEEPENING OF THE PASSAGE OVER THE BARS AT THE MOUTHS OF THE MISSISSIPPI.

In a late report, in reference to the deepening of the passage over the bars at the mouths of the Mississippi, over the signature of "Charles Ellet, Jr., Civil Engineer," are to be found many views which I consider erroneous, and utterly inconsistent with the plainest and clearest principles of Hydrodynamics; among these I have selected three propositions, which I intend to make the subject of a few brief remarks:

1st. That the bars at the mouths of the Mississippi are the result of the accumulated deposits-not of the water of the river, but of an under-current from the gulf.

2d. That confining the river in a channel of proper breadth, even if practicable, could not produce the effect of deepening the passage over the bars.

3d. That the true mode of so deepening the mouths of the Mississippi is dredging, or stirring up the material at the bottom.

Now, in order that Mr. Ellet's theory as to the formation of the bars at the mouths of the Mississippi, and my remarks in reference to it, may be well understood, I will first give a few extracts from his report:

"The current of the Mississippi sweeps over the bars at the mouths of the Passes, and at periods of flood, many miles out into the gulf, with a velocity almost undiminished by its contact with the waters of the gulf.

"But it has been suggested that the deposite at the bar is accelerated by the mixture of salt water with the fresh, which hastens the precipitation of the suspended material. This, doubtless, might occur if the assumed mixture should actually take place, to any considerable extent, at the bar. But the supposition is not supported by the fact. The river water does

not mix suddently with the sea, but rises upon it, floats over it, and rushes far out into the gulf on the top of the denser sea water, by which it is buoyed up.

"I tested this point repeatedly, and found uniformly a column of fresh water nearly seven feet deep in the gulf, entirely outside of land, and salt water at the depth of eight feet below the surface, and extending thence to the bottom. The passage from fresh water to salt water was extremely sudden, both at sea and on the bar.

"In fact, the river does not come down with a certain normal depth and speed, and encounter the gulf at the bar, and there lose its power in the contest. No such process takes place. The fresh water is lighter than the sea water, and floats upon it, as oil or any other lighter material floats on the surface of fresh water, or as the atmosphere rests on the surface of the There is no sudden union or consequent precipitation. There is no sudden destruction of velocity or consequent deposite of suspended silt. The river water, in virtue of its lesser density, rises upon the sea water, glides smoothly over it, passes out to the gulf, and slowly mixes with the sea water as the columns spread over the wider area, diminishing in depth, and is agitated and broken by the wind.

sea.

"But the water of the Mississippi does not move over the surface of the gulf at a speed of three feet per second, without imparting a portion of its motion to the sea. The equally impressible and fluid salt water, rubbed by the river which floats upon it, is carried forward by the friction developed at the surface in contact, the fresh water and salt water take the same direction towards the sea, and with nearly the same velocity, but yet keep separate.

"This state of things cannot exist to the bottom, for as the river water is for ever coming forward, if the salt water all flowed towards the gulf, it would all be carried out, and river water would take its place. Fresh water would then be found at the bottom, according to the supposition on which the plan of deepening, by contracting the channel or stopping up the bayous, depends. Salt water must come in from some quarter, to supply the current of sea water that is for ever setting towards the gulf, beneath the water discharged by the river. This salt water can only come from the sea, and can only come in along the bottom.

"It is, in fact, the principle of the eddy that is here at work, the movements being exhibited in a vertical, instead of a horizontal, plane.

"Now, the question is, how does this account for the existence of the bar? The fresh water running out cannot produce the deposite, for it has velocity enough to sweep away a foundation of coarse gravel. The outpouring salt water, immediately beneath the fresh, cannot produce a deposite, because it also has a velocity seaward, strong enough to remove anything that is brought down by the Mississippi. The salt water coming in from the gulf might produce, and I doubt not does produce, a deposite; for it passes over the soft, muddy bottom of the gulf, and moves into the river, and along the bar, at a very slow rate."

According to these facts and this reasoning, there must be usually on the bars three distinct strata of water:

"1st. Fresh water, running out at top, found by experiment on the southwest bar, to have a velocity of three feet per second.

"2d. Salt water below the fresh, also running out with nearly the same velocity at top; and

"3d. Salt water coming in slowly along the bottom, and apparently a sheet of salt water between that running out and that coming in, which will be without motion.

out.

"But, as already said, and is obvious, all the sea water that comes in must go out again. It comes in along the bottom, and it must go out between the column of salt water coming in and that of the fresh water going Each particle of salt water, therefore, must change its direction and position in elevation. It must pass from an inward bound lower strata to an outward bound upper strata. But in passing through this change of motion its velocity up stream must be neutralized. It passes, to use a technical term, the 'dead point.' At this point it may cease to bear its whole burden of mud, which it has brought from the gulf, further forward. It leaves it, or a portion of it, at the turning point. This turning point is the place where the bar, for the time being, is in process of formation. But as the upper and lower strata are moving in opposite directions, the intermediate column must, of necessity, have a rotary motion; that motion must be shared by the lower column of salt water, and this turning point must, therefore, be found at the same time at different places along the bar."

From these extracts, it will be seen Mr. Ellet contends that the current of the river, flowing through the mouths of the Passes of the Mississippi, does not meet with sufficient resistance from the waters of the gulf to check its velocity; and, consequently, that it does not deposite the sedimentary matter which it brings from above, and so cannot have caused the accumulations of mud which form the bars; and that the fresh water of the river flowing out into the gulf, over the bars, does not even extend sufficiently in depth to reach the bars, consequently, can neither add to, nor diminish them, as the lower depth is occupied by the stream of salt water flowing in from the gulf, which stream, he says: "Might produce, and I doubt not does produce, the immense accumulation of alluvial sediment, of which the bars are composed."

But these bars are not of such a character as would be formed by any influx from the sea. They are composed, nearly altogether, of soft mud, or alluvial soil; such as must have been brought down by the river, without such a mixture of sea sand, as they certainly would have, were they formed by the direct agency of a current of sea water flowing in from the gulf. Bars formed by the direct agency of the sea, are composed of denser and firmer materials than those which compose the Mississippi bars, and which Mr. Ellet himself informed us, are frequently ploughed through to the depth of three or four feet, by ships passing in and out of the river.

But even admitting the existence of the under-current from the gulf, spoken of by Mr. Ellet, it cannot be of such a character as could possibly have accumulated such a mass of deposite, in the face of the current of the river flowing through the Passes. This under-current is not a stream of great or concentrated volume and velocity, with sufficient scouring power to scoop up from the bottom of the gulf the immense deposites which compose the bars. On the contrary, it is a shallow stream, flowing, in time of flood only, from the open sea against the current of the river, which "passes over the soft, muddy bottom of the gulf-and moves into the river, and along the bar, at a very slow rate," so says Mr. Ellet. He also says: "The current of the Mississippi sweeps over the bars at the