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These extraordinary towns were ten miles apart, a few months ago, but were growing so fast that they may possibly be joined now, and getting along under a single mayor. At any rate, within five years from now there will be at least such a substantial ligament of buildings stretching between them and uniting them that a stranger will not be able to tell where the one Siamese twin leaves off and the other begins. Combined, they will then number a population of two hundred and fifty thousand, if they continue to grow as they are now growing. Thus, this center of population at the head of Mississippi navigation, will then begin a rivalry as to numbers, with that center of population at the foot of it--New Orleans.