Some old settled science

The role model for contemporary extrapolation from scientific models is apparently Mark Twain, who wrote in Life on the Mississippi back in 1883:

The Mississippi between Cairo and New Orleans was twelve hundred and fifteen miles long one hundred and seventy-six years ago. It was eleven hundred and eighty after the cut-off of 1722. It was one thousand and forty after the American Bend cut-off. It has lost sixty-seven miles since. Consequently its length is only nine hundred and seventy-three miles at present.

Now, if I wanted to be one of those ponderous scientific people, and ‘let on’ to prove what had occurred in the remote past by what had occurred in a given time in the recent past, or what will occur in the far future by what has occurred in late years, what an opportunity is here! … Please observe:–

In the space of one hundred and seventy-six years, the Lower Mississippi has shortened itself two hundred and forty-two miles. This is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oolitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen.

Oddly enough, we covered this process in middle-school science: the formation of oxbow lakes.

(From Old Grouch, riffing off an observation by Roberta X.)


  1. fillyjonk »

    7 November 2010 · 4:17 pm

    Yes, yes, but what’s happening to the actual thalweg?

  2. CGHill »

    7 November 2010 · 4:34 pm

    Unless I’m misremembering Bernoulli, as the river shortens it should speed up considerably and the line should straighten up a bit.

  3. Old Grouch »

    18 November 2010 · 11:43 am

    The Constructal Law of Flow Systems (and note the first comment).

  4. CGHill »

    18 November 2010 · 1:10 pm

    Hmmm. So this situation obtains only long enough to get halfway through the next cycle. Fascinating.

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