the proposed bed will effectually prevent the removal of its materials, and the irregularity of the deposit of such sediment and sand as may be brought down from the higher parts of the river, which I am justified in consider ing the chief evils of its present condition, and the result entirely of those defects which I propoee to remedy.

Character of the proposed Improvement.The special character of the system which I propose for the improvement of the Mississippi River, may be thus stated:

Ist. The bottom of the bed will have a concave form, with the greatest depth in the middle, with lateral sides rising progressively towards the top of the banks, so that the current will be completely centralized.

execution, are once confirmed in the public mind by experience, it will afford a model for regulating and embanking such other rivers as may require improvement, and be adopted in preference to any other, with such slight modifications as the peculiar character of each may require. I am convinced that this system, fully and properly carried out, will entirely prevent the too frequent disasters caused by inundation, and secure to navigation a mid-channel of uniform, constant, and sufficient depth everywhere, and at all seasons.

These advantages appear to me to be sufficiently important, and to have enough claim upon public interest, to authorize my asking for this system of improvement, and the rea2d. That the action of the current will be sons upon which it is based, that attention strongest in the middle, where it can do no and examination, and the sanction of that apinjury; but, on the contrary, be useful in re-proval, which I think they deserve from the moving all materials which would otherwise well-informed part of the community, who be deposited there, and might tend to alter now begin to feel the necessity and importthe regularity and uniformity of the cross

section.

3d. That the high water cannot reach the levee except over a gentle plane, or slope, covered with grass, which will have a tendency to lessen its action, and thereby prevent abrasion; so that there will be no apprehension of its being broken through, or requiring any important repairs.

4th. That the borders of the bed being thus protected, and secured from the force of the current, and the middle kept deep and clear, the levees will not require to be as high as under the present system, and may be made of common earth, the interior slope being lined with grass; thus combining the least possible resistance to the passage of the water with economy in construction and facility of repair.

ance of improving the course of a river whose inundations cause so many ravages, and whose frequent changes threaten to interfere with the navigation of its channel.

Objections to the proposed Improvement.— The only objection that can be made to the mode of directing the course of the river, and of centralizing the current as proposed, is, that it will require land at some places for a new channel, and at others for extending the breadth of the present bed of the river. But it is certainly better that the planters who reside along its banks, and whose interests are so deeply involved in the future as well as the present condition of the river, should make a voluntary sacrifice of the necessary land, by which a perfect guaranty may be secured for the rest of the delta, than that their plantations should continue to be exposed, as they are at present, to heavy losses every year from inundations caused by the wearing away and breaking through of the levees.

5th. That the channel of the river, approx imating as nearly as practicable to a straight course, and the main force of the current being confined to the middle, and nowhere washing against the banks, there will be no The examination of a system of improvepossibility of the formation of shoals, and ment is often referred to persons who are not scarcely a probability of the existence of thoroughly acquainted with the subject, and snags, or sawyers, to impede navigation or who judge of the plan before them according render it dangerous. For such trees as may to ancient prejudices and opinions, which are be brought down from the upper course of the river, or its tributaries, will naturally be carried by the force of the current into the middle of the channel, where the depth and velocity will be greatest, and where they will meet with no impediment to stop or detain them in their onward course to the gulf.

not applicable thereto; and the proposed improvement being unfamiliar to every day's practice, it is rejected, and society deprived of all advantages which may arise from it, or would contribute to the advancement of its commercial and agricultural prosperity. We admit that government ought to be very Advantages of the proposed Improvement. cautious about adopting a system of improveI think that the proposed system for the im- ment suggested by persons who have no provement of the Mississippi River, on ac- experience, and who are unable to give a decount of its special advantages, and its econ- tailed account of the principles upon which omy, is not only the best, but the only prac- they base them. But propositions brought forticable one for permanently regulating the ward by competent persons, who have had channel and embanking the river; and that long experience in the practice of their prowhen its advantages, and the facility of its fession, ought to be received with less reserve

and more confidence. Instances are numer- the tendency to abrasion, change, and overous, in which yearly losses have been per- flow, has been yearly increased. This is all mitted to continue, until the aggregate that has been done for the river, the result amount has gone a hundred fold beyond the of which has been to increase its already exexpense that would have been sufficient, in isting defects; while nothing has been atthe first instance, to prevent them, and in tempted in aiding the discharge of the water, many cases the remedy has come too late to so as to reduce its height, or to relieve the save. The reluctance of governments to un- levees from its great pressure in time of flood, dertake the responsibility of new improve which is continually wearing them away and ments, has deprived some countries of oppor- breaking through; such as straightening the tunities of national preeminence which time course of the river, where it could be done by never threw in their way again. Indeed, if the making of properly directed cut-offs, or a fair estimate could be made, it would be altering abrupt curves into those of large found that the losses consequent upon the radii, or by centralizing the current. The refusal to adopt, or the procrastination of new very means used operate against the intended improvements of a public character, have object. To increase the convex banks and been greater than the actual expense of all the levees, also building new and raising the that have ever been undertaken, successful old, serves but to increase the resistance to or unsuccessful.

the motion of the waters, and add to their accumulation 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.

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 under- Conclusions.-In thus placing my views go a radical change, and the system of im- before the public, my desire is to confer a provement must be of a general, uniform and benefit upon my fellow-citizens of the state consistent character, before any real perma- of Louisiana, by presenting for their considnent benefit can be derived from the amount eration a mode of improving the Mississippi, of expenditure which the giving way of the consisting of a system for regulating and levees renders yearly necessary. It is, there- leveeing the channel, which combines that fore, the duty of the Legislature of Louisiana economy and security so indispensably necesto adopt some such system, as by that means sary in works of this kind. It needs no argu only can they hope to remedy the evils con- ment to prove that the evils arising from sequent upon the present condition of the the present condition of the river are yearly river; or relieve the agricultural interests increasing; and that the time has come along its banks from the heavy losses yearly when some general and uniform system for recurring; or save the commercial and real the permanent improvement of the channel estate interests from the utter ruin that now throughont the whole lower valley ought to threatens them. A heavy responsibility must be adopted. For the heavy losses and exrest upon each future Legislature of that penses entailed upon the planters by periodstate, for every neglect to perform so highly ical inundations already surpass, in the aggreimportant a duty. That the improvements hitherto attempted have proved insufficent 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

gate, 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 | Florida and the West Indies; and that is praccommercial and real estate interests from tically even now the real mouth of the Mistotal 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.

sissippi. But however this may be, we publish the investigations of Professor Riddell, which have not yet appeared in print.

To the Association of American Geologists and Nat

uralists:

give.

GENTLEMEN :-At your convention in 1845, you named me as one of the committee of three, to ascertain the amount of sediment carried into the sea by the Mississippi River; the result to be reported to you in 1846. The other members of the committee residing at a distance, I have been unable to profit by such The great size of the lower Mississippi, the a cooperation with them as would be desirextent of territory through which it flows, and able. What I can present you, will be mostly the vast and important intersts which have my individual observations, as yet necessarily grown into existence upon its borders, and incomplete, inasmuch as they extend through now lie exposed to the ravages of inunda- only a part of the year. I am of the opinion, tions, render it utterly impossible that its however, that the general average amount of power can be controlled, and its defects sediment, the year through, and one year with remedied, through the means of individual another, will not be found to vary essentially energy or individual capital. The improve- from the mean result which my observations ment of the river must be the work of that government whose people are the most The following table embraces the results of deeply interested in its accomplishment; and experiments upon Mississippi water, taken at upon the Legislature of that state must intervals of three days, extending from May devolve the highly important duty of select- 21 to August 13, 1846. The water was drawn ing and adopting the mode in which it shall up in a pail from a wharf near the mint, where be carried out. They can no longer neglect there is considerable current. Its temperathis duty in justice to themselves, for many ture was observed at the time, and the height of them are sufferers by the present con- of the river determined. Some minutes afterdition of the river, and personally interested ward, the pail of water was agitated, and two in the matter; nor in justice to the whole samples of one pint each measured out. The state, whose every prosperity is involved in glass pint measure was graduated by weighit. For the manner in which they may ing into it at 60° Fahr. 7295.581 grains of disundertake to discharge this duty, they will tilled water, and marking the height with a incur a heavy responsibility; but should diamond. 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.-Albert Stein.

pre

From the pint samples of water, after standing a day or two, most of the matter mechanically suspended would subside to the bottom of the containing vessels. Near two thirds of the clear supernatant liquid was next decantMISSISSIPPI RIVER-DEPOSITS AND ed, while the remaining water, along with the CHANGES AT ITS MOUTH.-We have been pre- sediment, was in each instance poured upon a sented by Professor Riddell, at our solicitation, double filter, the two parts of which had with the manuscripts of the Report prepared viously been adjusted to be of equal weight. by him to be read before the Society of Ame- The filters were numbered and laid aside, and rican Geologists, and a letter furnished by ultimately dried in the sunshine under like him to Professor Lyell upon the subject of circumstances, in two parcels, one embracing the sedimentary deposits of the Mississippi. the experiments from May 21st to July 15th; We regard the subject as of deep interest and the other from July 17th to August 13th. importance, both as a matter of scientific re- The difference in weight between the two search and of practical utility. The changes parts of each double filter was then carefully going on at the mouth of the Mississippi can- ascertained, and as to the inner filter alone not be unimportant to our commerce. The the sediment was attached, its excess of weight remark has been made by some one, that in a indicated the amount of sediment. I emremote age our shipping will leave the river ployed Mr. John Chandler, a skilful manipuon entering the ocean somewhere between lator, to assist me in all these operations.

.water.

B.
7.00

9.00

heard of extended 200 feet below the level of the sea. M. W. Hoffman, Esq., an intelligent lawyer of this city, informs me that in May and June, 1828, he daily witnessed the progress of this boring at the old fort, near the mouth of the bayou St. John, on the shore of Lake Pontchartrain, a few miles north of the city. Harvey Elkins, then proprietor of 9.12 the hotel, bored to the depth of 207 feet, in search of pure water. He desisted because the auger broke. A copious supply of water arose, with occasional evolutions of gas; the quality of the water being brackish, like that of the wells in the city. Some few recent fossils were occasionally brought up, such as shells, crustacea, bones, and part of a deer's horn. Indian pottery was found at the depth of 30 feet. The strata perforated were all of the delta formation, the lowest being a hard 7.40 blue, silicious clay, like that now found at the bottom of the Mississippi river.

6.10

4.90

5.60

6.80

6.30

6.00

6.15

9.00

8.48

1816.

A.

May 21.... 10 11

720

6.66

66 25.

10 11

8.10

5.45

8.78

As to the quality of New-Orleans well water, alluded to above, it will be proper to quote some observations thereon, made by me in 1837. (Gibson's New-Orleans Directory, 1838, p. 292.) "The proportion of mineral matter dissolved in the water varies in different seasons of the year, it being the greatest after long-continued dry weather, when the wells are lowest. A well at No. 328 Camp street, ten feet in depth, on the 22d of 4.57 September, yielded by evaporation one part of solid residue to 1200 by weight of water. On the 20th of December, 1 to 1094. This residue is an olive-colored powder, with a sharp taste. Nearly one fourth of it appears to be organic and organized matters, such as the sporules of algae, microscopic animalcules and their ova. One half only of the whole residue can be re-dissolved in water; oxide of iron, carbonate of lime, and the organized matters still retaining the solid condition.

5.75

5.72

3.34

3.40

2.85

By repeated trials in the first week in July, by direct and careful comparison with disThe saline and other dissolved impurities, tilled water, the specific gravity of the filtered contained in the Mississippi river water, river water was found to be 1.00025; conse-doubtless vary very much at different seaquently a pint of such water at 60° weighs 7297.404 grains. Thence by weight, the ratio sons of the year; dependent upon the partiof the sediment to the water is as 1 to 1158.3. the ascendency. On the 20th of August, 1846, cular tributary river which happens to have In the months of June and July, 1843, I made several experiments after a different the solid residue from the evaporation of carefully filtered water was by weight 1 to nearly manner, and obtained an average of 10,000 of the water. But I presume the mean the proportion of sediment, being less than proportion the year through would be found the above by nearly one fourteenth part of considerably less. Besides organic matter, the whole. The proportion 1 to 1155 is prob- this residue was found to contain chrome, ably nearest the truth, as it is based upon lime, magnesia, soda, carbonic acid, sulphuric experiments embracing the most usual aver-acid a trace, oxide of iron a trace, At the age variation of 10 feet in the stage of water. ratio of 1 to 10,000, suppose one half to conWe have no direct information as to the tribute permanently to the saline matters of full depth of the delta formation about New-the ocean, one cubic foot of sea water is deOrleans. The deepest boring that I have rived from every sum of 727 cubic feet of

Sediment in
grammes.

Mississippi water that runs into the Gulf of
Mexico. This is equivalent to the production No. 2-Opposite Carthage,
of 0.043 of a cubic mile of sea water of pre-
sent density every year, or to a cubic mile No. 3-Opposite New-Or-
of sea water produced in about 23 years.

With a view to learn the main composition of the Mississippi sediment, Mr. Chandler and myself submitted to careful analysis 100 grains taken the 20th of May, from the river margin, and dried at about 212° Fahr. before weighing. We found

Silica...

Grains.
.74.15

9.14
4.56

2.08

1.52

Alumina..

Oxide of iron.

0.04

PROF. LYELL: Sir:-In accordance with your request, I proceed to make estimates from the best data in my possession, respecting the deposition of sediment from the waters of the Mississippi, and the probable length of time heretofore occupied in the delta

formation.

On the 17th of August, 1841, when the Mississippi was about five feet below its average height, I made careful soundings directly across from the mint, where the width is very near one third of a mile. The soundings were made at nearly equal intervals, beginning twelve rods from the wharf, and ending eight rods from the opposite shore, showing the following depths in fathoms, viz.: 11, 13, 13, 15, 23, 23, 224, 224, 19, 131, 104, 81.

June, Dr. Drake..

Ratio by wt.

to the whole.

0.38....1-1250

leans, June, Dr. Drake.. 0.35....1-1350 No. 4-Opposite New-Or

leans, July 6th, 1843... 0.40....1-1190 Average ratio of dry sedimentary matter in numbers 1, 2, 3, 4, to the weight of water and sediment, = near 1-1245.

From the best information which I have ob tained, derived principally from C. G. Forshey, Esq., of Vidalia, Engineer, I think the superficial area of the true delta formation of the Mississippi, or below Baton Rouge, where the last bluffs show themselves, may be taken as 15,000 square miles; constituting a region of mean width 75 miles, and mean length 200 miles.

Probably the depth of the alluvion may be set down at one fifth of a mile, by inference from the depth of the Gulf of Mexico.

I will now proceed to make some numerical approximations relevant to the subject. Width of the river opposite the mint

mile 1,760 feet.

=

Mean depth, 100 feet.

Mean variety of the current per second,
say 2 feet...

(3)
Mean amount of sedimentary matter by
weight 1-1245, by volume near 1-8000. (4)
cubic feet of water passing per second. (5)
(1)X(2)X(3) = 1760×106×2=352,000
(4)X(5)=1-8000×352,000 = 117 cubic
feet of earth per second..

(6)

370,275 and 400 cubic feet of earth (6) Xsec. in 1 year-117331,557,600= borne down by the current in 1 year.. (7) (7)÷cubic feet of a cubic mile-025.155 of a cubic mile of earth brought past New(8) Orleans in 1 year. One fifth of a mile-(8)-7.95 years occusquare mile of delta, as at present rates (9) pied in depositing the equivalent of one (9)X15,000 square miles of delta below Baton Rouge=7.95X15,000-119,250 years occupied in its deposition.

Thus, giving a broad margin for inexact In July, 1843, I made some careful experiments to determine the amount of sediment- data, the latest formed considerable sum of ary matter in the Mississippi water, which the earth's dry land surface must have enthen possessed about an average degree of grossed in its continuous matter and enlargeturbidness. For each experiment I used near ment up to the present time, the round period a pint of water, 475.85 grammes Fr. actual of one hundred thousand years. weight. The sediment was allowed near ten days for natural subsidence; it was then carefully collected, allowed to dry spontaneously, and when effectually dry, was carefully weighed.

Sediment in Ratio by wt.
to the whole.

grammes.

No. 1-Procured from op-
posite Randolph, by Dr.
Drake, in June, 1843... 0.40....1-1190

Respectfully, your obedient servant,
J. L. RIDDELL.

NOTE BY THE EDITOR.-Professor Lyell having been referred to in the article above, we' may remark that there is before us a letter written by him to Professor Riddell, in which he remarks:

"On reading your valuable paper I perceive that you state that the water, when taken for