Scientific American Supplement, No. 810, July 11, 1891

Chapter 10

Chapter 103,892 wordsPublic domain

To La Salle belongs the honor of tracing the true course of the Mississippi river. He charted it with a faithfulness and accuracy that would do credit to the surveys of the present day. He seemed to have noted all the important feeders and tributaries, correctly locating their points of confluence. He did not cease his work until he reached the Gulf of Mexico.[3] So not only was La Salle the most indefatigable explorer of this region, but he also earned the credit of having made the most important discovery.

[Footnote 3: From the best information I can gather I am unable to decide to my own satisfaction whether or not La Salle discovered the Red River. It is not improbable that he never saw this stream, for it is more than likely that at that time, Red River poured its waters directly into the Gulf of Mexico, through Atchafalaya and Cocoudrie Bayous. That these were formerly a part of the channel of Red River, there can be no doubt. The sluggish swale that now leads from the river to the Gulf is a silted channel that was formerly large enough to carry the whole volume of Red River. Such changes in the channel of a river, when the latter flows through "made" soil, are by no means infrequent. It is only a few years since the Hoang River, "the sorrow of Han," broke through its restraining banks, and poured its flood into the Gulf of Pe-chee-lee, 350 miles distant from its former mouth.]

With La Salle's exploration the future importance of the Mississippi began; and though the railway has of late years largely supplanted it as a commercial highway, yet, with the possible exception of the Ganges, no other river in the world transports yearly a greater tonnage of merchandise. The early traders were content to carry their supplies back and forth in canoes. As settlement and business increased, the canoe gave place to the raft, and the raft yielded to the flatboat. In the course of time, steam was applied to the propulsion of boats, and the flatboat yielded to the inevitable: the palatial steamboat was supreme. But the days of the steamboat were numbered when the civil war cast its blight over the land; and when the years of strife were over, so also was the river traffic which had created the floating palaces of the Mississippi. There were several things that operated to prevent the reorganization of the fleet of steamboats which for size, beauty and capacity were found in no other part of the world. Many of these boats had been destroyed, and the companies that owned them were financially ruined. Most of those remaining were purchased or confiscated for military purposes, and rebuilt either as transports or as gunboats. A period of unparalleled railway construction began at the close of the war, and most of the traffic was turned to the railway. Finally, it was discovered that a puffy, wheezy tug, with its train of barges, costing but a few thousand dollars, and equipped with half a score of men, could, at a much less rate, tow a vastly greater cargo than the river steamer. That discovery was the knell of the old-time steamboat, and the beginning of a new era of navigation. Powerful as the railway may be, we cannot shut our eyes to the fact that a tug and train of barges will carry a cargo of merchandise from St. Paul to St. Louis for one-tenth the sum the consignee must pay for railway transportation. So, to-day, the river is just as important as a highway of commerce as it was in the palmy days of the floating palace and river greyhound. Railway traffic has enormously increased, but river traffic along the most wonderful of streams has not materially lessened.

The Mississippi is certainly a wonderful river. From Elk Lake to the Gulf of Mexico it has a variable length of about 2,800 miles; from Pass à l'Outre to the head of the Missouri its extent is nearly 4,200 miles--a length not equaled by any other river in the world. It is evident, by a moment of reflection, that a river which traverses a great extent of latitude offers much greater facilities for commerce and settlement than a longitudinal river. The Mississippi traverses a greater breadth of latitude than any other river, except the Nile, for its sources are in regions of almost arctic cold, while its delta is in a land that is practically tropical. The volume of its flood is surpassed by the Amazon and, perhaps, the Yukon. It discharges, however, three times as much water as the Danube, twenty-five times as much as the Rhine, and almost three hundred and fifty times as much as the Thames. It has several hundred navigable tributaries, and its navigable waters, stretched in a straight line, would reach nearly three-fourths the distance around the earth. It is one of the most sinuous of rivers. In one part of its course it flows in a channel nearly 1,400 miles long to accomplish, as the crow flies, the distance of 700 miles. In more than one place the current forms a loop ten, twenty and even thirty miles around, rather than to cut through a neck perhaps not half a mile in width. It is one of the most capricious of rivers, for its channel rarely lies in the same place during two successive seasons. The river manifests a strong inclination to move east; and were La Salle to repeat his memorable voyage, he would touch in scarcely half a score of places the course he formerly traveled; or if he were to go over exactly the same course, he must of necessity have his boats dragged over the ground, for almost the entire course over which he traveled is now dry land. Since that time the river has deserted almost all of its former channel, as if to repudiate its connection with the after-dinner treaties of two hundred years lang syne; in places its channel lies to the west, but for the greater extent it is to the eastward.[4]

[Footnote 4: "The bed of the river is so broad that the channel meanders from side to side within the bed, just as the bed itself meanders from bluff to bluff; and, as by erosions and deposits, the river, in long periods of time, traverses the valley, so the channel traverses the bed from bank to bank, justifying the remark often heard, that 'not a square rod of the bed could be pointed out that had not, at some time, been covered by the track of steamboats.'"--J.H. SIMPSON, _Col. Eng., Brevet Brig.-Gen., U.S.A._]

PHYSICAL.

The lower Mississippi is among the muddiest streams in the world. During the average year it brings down 7,500,000,000 cubic yards of sediment, discharging it along the lower course, or pushing it into the Gulf. As one thinks of the small amount of sediment held in a gallon or two of river water, a comprehension of this vast amount of silt is impossible. It is enough to cover a square mile in area to a depth of 268 feet. In five hundred years it would build above the sea level a State as large and as high as Rhode Island. Thus, by means of this sediment, the river has pushed its mouths fifty miles into the sea, confining its flow within narrow strips of land--natural levees made by the river itself.

The Mississippi is notable for its varying length. Within the memory of the oldest pilot the length of the river between St. Louis and New Orleans has varied more than one hundred and fifty miles, being sometimes longer and sometimes shorter, as the year may be one of drought or of excessive rainfall. Occasionally the river will shorten itself a score of miles at a single leap. The shortening invariably takes place at one of its long sinuous curves for which it is so remarkable. At a season when the volume of water begins to increase, the narrow neck of the loop gives way little by little under the continuous impact of the strengthening current. Narrower and narrower it grows as the water ceaselessly cuts away the bank. Finally the barrier is broken; there is a tumultuous meeting of waters; the next steamboat that comes along goes through a new cut; and a moat or ox-bow lake is the only reminder of the former channel.[5]

[Footnote 5: One of the most noteworthy examples of these cut-offs is Davis'. This cut-off occurred at Palmyra Bend, eighteen miles below Vicksburg. The mid-channel distance around the bend was not far from twenty miles; the neck was only twelve hundred feet across. The fall of the river, measured around the bend, was about four inches per mile; the slope, measured across the neck, was about five and one-half feet, nearly twenty feet per mile. Inasmuch as the soil in the neck was wholly alluvial, the current cut its new channel with exceedingly great rapidity, soon clearing it out a mile in width and more than one hundred feet in depth. The water rushed through the channel with such a velocity that steamboats could not breast its flow for many weeks, while the roaring of its flood could be heard many miles away. The influence of the cut-off was felt both above and below Vicksburg for several years after. The rate of erosion has been perceptibly increased above Vicksburg: and it is not unlikely that the cut-off which occurred a few years later at Commerce, about thirty miles below Memphis, was a result of Davis' Cut. Other recent cut-offs have occurred near Arkansas City, below Greenville, near Duncansby, below Lake Providence at Vicksburg, and at Kienstra. The latter place is below Natchez; all the others are between Natchez and Memphis. A double cut-off is strongly threatened at Greenville.]

In 1863 the city of Vicksburg was situated on the outer curve of such a loop. At that time General Grant and his army were on the opposite side of the river, and the whole power of the Federal government was directed upon devising how the army might cross it and capture the long-beleagured city. So an army engineer conceived the idea of turning the river around the rear of the army. Accordingly, a canal was cut across the loop, in order to make an artificial channel through which its current might run. But the river steadfastly refused to accept any channel it had not itself made, and the ditch soon silted up. Twelve years or more afterward there was trouble; for the river, which had all this time so persistently ignored the canal, one stormy night, when its current was considerably swollen, took a notion to adopt the canal that it had so long refused. Next morning the good people of Vicksburg woke to find their metropolis, not on the river channel, but practically an inland town overlooking a stagnant mud flat. The town of Delta, which, the night before, was three miles below Vicksburg, was, in the morning, two miles above it. Since that time, energy and intelligence have conspired in its behalf, and Vicksburg is still an important river port; but the channel of the river is persistent, and constant effort and watchfulness alone keep a depth of water sufficient for the needs of navigation before the wharves.

The average inhabitant of the flood plain of the Mississippi is not surprised at this capriciousness of the river, for long experience has taught him to look for it. During seasons of mean or of low water, there is little or no trouble; but when floods begin to swell the current, then it is high time to be on the alert, for no one knows what a day or even an hour may bring forth. Perhaps a snag, loosened from the bank above, may come floating down the stream. It strikes a shallow place somewhere in the river, and thereupon anchors in mid-channel. Directly it does, a small riffle or bar of silt will form around it, and this, in turn, sends an eddying current over against the bank. By and by the latter begins to be chipped away, little by little. Perhaps the corrosion of the bank might not be noticed except by a bottom land planter or a riverman. But there is no time to be lost. If some unfortunate individual happens to possess belongings in that vicinity, he simply lays aside his coat and works as if he were a whole legion doing Cæsar's bidding; he well knows that in a very few hours the river will be swallowing up his real estate at the rate of half an acre to the mouthful. It is certainly hard to see one's earthly possessions disappear before the angry flood of the river, but the bottom land planter does not complain, because the experience of generations has taught him that he must expect it. A queer fortune befell Island No. 74.

Between the States of Arkansas and Mississippi there is a large island, which, for want of a name, is commonly known as Island No. 74.[6] This slip of insular land is probably the only territory within the United States and not of it, for this island is without the boundaries of either State, county or township. It is not under control of the government, because it is in the possession of an owner whose claim is acknowledged by the government. The anomalous position of the island as to political situation is due to the erosion of the river as an active and the defects of statutory law as a passive agent. According to the enactment whereby the States of Arkansas and Mississippi were created, the river boundary of the former extends to _mid-stream_; that of the latter to _mid-channel_. Herein is the difficulty. A dissipated freshet turned the current against the Mississippi bank, and shifted the former position of mid-channel many rods to the eastward, so that the fortunate or unfortunate owner found his possessions lying beyond both the mid-river point of Arkansas and the mid-channel line of Mississippi. The owner of the plantation may be unhappy at time of election, for he is practically a non-resident of any political division. His grief, however, is somewhat assuaged when the tax gatherer calls, for, being outside of all political boundaries, he has no taxes to pay.

[Footnote 6: For convenience to navigation, the islands in the lower Mississippi, beginning at St. Louis, are numbered. Many of them, however, have local names by which they are frequently known.]

Within a few years the town of Napoleon, which has already been mentioned as the site which beheld the cross erected by Marquette and the seizure of La Salle, was the scene of still another chapter in history. Almost two hundred years from the time when Joliet and Marquette beheld the historic ground, the river turned its current against the banks, and in a few hours the crumbling walls of an old stone building, half a mile or more from the river banks, were the surviving monument that marked the former location of the town.

The Mississippi is indeed a grand study, and the people who have lived in its valley during past ages have seen the river doing just what it is doing to-day; and as race has succeeded race, each in turn has seen the landmarks of its predecessors swept away by its angry flood and buried beneath its sediment. Ever since the crests of the Appalachian and Rocky Mountains were thrust up above the sea, the river has been wearing them away, and bearing the scourings to the vast plain below. In the time of its building it has made the greatest and the richest valley on the face of the earth; next to that of the Amazon it is the largest, covering an area of one and one-quarter million square miles. The river and its tributaries drain twenty-eight States and Territories--an area equal to that of all Europe except Russia. This basin includes half the area of the United States, exclusive of Alaska. It is five times as large as Austria-Hungary, six times the size of France or Germany, nine times the area of Spain, and ten times that of the British Isles. Measured by its grain-producing capacity, this valley is capable of supporting a larger population than any other physical region on the face of the earth. Already it is the foremost region in the world in the production of grain, meat and cotton. The rich soil, sedentary on the prairie and alluvial in the bottomlands, is almost inexhaustible in its nutritious qualities. The soil cannot be "worn out" in the bottomlands, for nature restores its vitality by bringing fresh supplies from the highlands as fast or faster than the seed crop exhausts it. Sixty bushels of wheat or two bales of cotton may be harvested from an acre of bottom lands. So vast in proportions is the yearly crop of food stuffs that more than three hundred thousand freight cars and about two thousand vessels are required to move the crop from farm to market. One hundred and twenty-five thousand miles of railway, fifteen thousand miles of navigable water, exclusive of the Great Lakes, and several thousand miles of canals are insufficient to transport this enormous production; thousands of miles of railway are therefore yearly built in order to keep pace with the growth of population and the settlement of new lands. To the natural resources of the soil add the enormous mineral wealth hidden but a few feet below the surface, and wonder grows to amazement. Coal fields surpassing in extent all the remaining fields in the world; iron ore sufficient to stock the world with iron and steel for the next thousand years; copper of the finest quality; zinc, lead, salt, building stone and timber, all in quantities sufficient for a population a hundred times as great. Is it strange that wise economists point to this territory and say, "Behold the future empire of the world"? Where in the wide world is another valley in which climate, latitude and nature have been so liberal?

It is only a few years since the Indian and the bison divided between them the sole possession of this region. What a change hath the hand of destiny wrought! What a revelation, had some unseen hand lifted the curtain that separated the past from the future! Iron, steam and electricity have in them more of mysterious power than ever oriental fancy accredited to the genii of the lamp, and the future of the basin of the Mississippi will be a greater wonder than the past.

The feast of La Salle was the death warrant of the Indian, and the Aryan has crowded out the Indian, just as the latter evicted the mound builder--just as the mound builder overcame the people whose monuments of burned brick and cut stone now lie fifty feet below the surface. Only a few centuries have gone by since these happenings; can we number the years hence when rapacious hordes from another land shall drive out the effete descendants of the now sturdy Aryan?

(_To be continued_.)

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FREEZING MIXTURES.

The following selection of mixtures causing various degrees of cold, the starting point of the cooling being indicated in the first column, will probably serve many purposes. It should be stated that the amount of depression in temperature will practically be the same, even if the temperature to start from is higher. Of course in the case of snow it cannot be higher than 0° C. (32° F.) But in some cases it is necessary to start at a temperature below 0° C. For instance, the temperature of -49° C. may be reached by mixing 1 part of snow with ½ part of dilute nitric acid. But then the snow must have the temperature -23° C. If it were only at 0° C., the depression would be only to about -26° C.:

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THE APPLICATION OF ELECTROLYSIS TO QUALITATIVE ANALYSIS.

By CHARLES A. KOHN, B.Sc., Ph.D., Assistant Lecturer in Chemistry, University College, Liverpool.

The first application of electrolysis to chemical analysis was made by Gaultier de Claubry, in 1850, who employed the electric current for the detection of metals when in solution. Other early workers followed in this direction, and in 1861 Bloxam published two papers (J. Chem. Soc., 13, 12 and 338) on "The application of electrolysis to the detection of poisonous metals in mixtures containing organic matters." In these papers a description is given of means for detecting small quantities of arsenic and of antimony by subjecting their acidulated solutions to electrolysis. The arsenic was evolved as hydride and recognized by the usual reactions, while the antimony was mainly deposited as metal upon the cathode. The electrolytic method for the detection of arsenic, in which all fear of contamination from impure zinc is overcome, has since been elaborated by Wolff, who has succeeded in detecting as little as 0.00001 grm. arsenious oxide by this means (this Journal, 1887, 147).

In a somewhat different manner the voltaic current is made use of in ordinary qualitative analysis for the detection of tin, antimony, silver, lead, arsenic, etc., by employing a more electro-positive metal to precipitate a less electro-positive one from its solution.

The quantitative electrolytic methods of analysis, some of which I had the honor of bringing before the notice of the Society some time back (this Journal, 1889, 256), have placed a number of methods of determination and separation of metals in the hands of chemists, which can be employed with advantage in qualitative analysis, especially in case of medical and medico-legal inquiry. These methods are not supposed to supersede in any way the ordinary methods of qualitative analysis, but to serve as a final and crucial means of identification, and thus to render it possible to detect very small quantities of the substances in question with very great certainty. As such they fulfill the required conditions admirably, being readily carried out, comparatively free from contamination with impure reagents, and capable of being rendered quantitative whenever desired.

In conjunction with Mr. E.V. Ellis, B.Sc., I have examined the applicability of the electrolytic methods for the detection of the chief mineral poisons (with the exception of arsenic, an electrolytic process for the detection of which has already been devised, as described), viz., antimony, mercury, lead, and copper.