Within a few days past, the boatmen, merchants, &c., on the Ohio, were much excited at the report that a mob of the Mississippi Rebels had planted cannon at Vicksburg, and were determined to hail and stop every passing steamboat. This would be not only an outrage against the Constitution, but equivalent to an act of war against the States which border on the Upper Mississippi. It created great excitement at Cincinnati—because the river is the natural outlet of her business. But there was no hesitation; the captains of the steamboats, and their mercantile owners, were determined to submit to no such outrage, and therefore they were prepared to arm their steamboats and give the Mississippi rebels a taste of the cold lead they so freely offered to the peaceable citizen, in the pursuit of his lawful traffic.

There can be no doubt that any forcible obstruction of the Mississippi, would at once lead to a war between the West and the South. In 1802, when Spain held Louisiana, her obstructions to our boatmen would soon have caused a war. Jefferson fortunately purchased Louisiana, and thus a war was avoided. The West then contained a population of only a few thousand, now those thousands have expanded into millions, who, of themselves, possess all the power of a great nation. They will not submit an hour to any extortion or robbery attempted to be practiced by Mississippi or Louisiana. They demand, and will have the free navigation of the Mississippi,—Secession or no Secession. Senator Johnson, of Tennessee, and Winfield Scott have both shown that in case Secession prevails—a war is inevitable between the West and the Cotton States on the Lower Mississippi. The peaceable navigation of that great river is almost impossible, and therefore they advise the Secessionists to pause, before they provoke the power of the Great West—which is essentially the military portion of our Republic!

The last despatches bring no further accounts of obstructions of the Mississippi. So we are inclined to the opinion that the Mississippi Rebels have given up their intention of stopping passing steamboats. They would not fire into more than one steamboat, before they would witness such an invasion from the North—as would bring to them the actual realities of War!