1. Fresh water, running out at the top with a velocity of three miles an hour.
2. Salt water, beneath the fresh, also running out at about the same velocity.
3. A reflex flow of salt water, running in slowly at the bottom.
It is this inward current, he thinks, that produces the deposit, and in doing so carries with it no small degree of sea drift. The influx of the lower column flowing up stream, after it passes the dead point, is allowed time and opportunity for the sediment to deposit. The principle of the reflex current is somewhat that of an eddy, not only produced by the conflict of two opposing bodies of water, but also is much influenced in the under currents by the multitude of estuaries presented by the irregular sea front of the coast.
A gentleman, who seems to have taken a very statistical view of these bars, makes the following business-like and curious calculation as to their immensity: we introduce it on account of its originality. He says the average quantity of water discharged per second is five hundred and ten thousand cubic feet. The quantity of salt suspended, one in three thousand by volume. The quantity of mud discharged, one hundred and seventy cubic feet per second. Considering seventeen cubic feet equal to one ton, the daily discharge of mud is eight hundred and sixty-four thousand tons, and would require a fleet of seventeen hundred and twenty-eight ships, of five hundred tons each, to transport the average daily discharge. And to lift this immense quantity of matter, it would require about seven hundred and seventy-one dredging machines, sixteen horse power, with a capacity of labor amounting to one hundred and forty tons, working eight hours.
Another class of sedimentary formations met with along the banks of the Mississippi are the battures. There is one remarkable instance of these in front of New Orleans, which has led to much private dispute, and even public disturbance, as to ownership. Within sixty years, in front of the Second Municipality of the city, the amount of alluvial formations susceptible of private ownership were worth over five millions of dollars, that is, nearly one hundred thousand dollars per annum, and the causes which have produced them are still at work, and will probably remain so. As far back as 1847 these remarks were made upon the subject: 'The value of the annual alluvial deposits in front of the Second Municipality now is not less than two hundred thousand dollars, and, with the exception of the batture between the Faubourg St. Mary line and Lacourse street, all belongs to this municipality.' 'Such a source of wealth was never possessed by any city before. In truth, it may be said that nature is our taxgatherer, levying by her immutable laws tribute from the banks of rivers and from the summits of mountains thousands of miles distant to enrich, improve, and adorn our favored city.' There are numerous other examples of the kind going on elsewhere along the river.
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