The main features of the rebel plan of war in the West were to seize and hold Missouri, and, as a consequence, Kansas and Nebraska, and thus threaten or invade the free States of the North-west from that point; to hold Kentucky and Tennessee, and, if possible, to cross the Ohio, and make the Northern States the theater of the war; or, in case they should be unable to invade the North, to maintain their battle line unbroken along the Ohio and through Missouri; to keep the great rivers closed, and thus holding back the North, and being secure within their own territory, at length compel the recognition of their independence.  They certainly presented to the North a most formidable front, a line of defenses which was indeed impregnable to any means of assault which the Government at first possessed.  No army could be moved into Tennessee by land alone, because the line of communication with a Northern base could not be held secure, and a defeat far from the Ohio would be the destruction of an army, and open the road for an invasion of Illinois, Indiana, and Ohio, and the destruction of their cities.

It was quite evident that no impression could be made upon the power of the rebellion in the West, until a firm foothold could be gained in Kentucky and Tennessee, and until the Mississippi could be wrested from the conspirators’ control.  It was clear that the whole seaboard might be regained, even to Florida, and yet the rebellion remain as dangerous as ever, if the rebels could hold the Mississippi River and the valley up to or near the Ohio.

France was looking with eager eyes toward Texas, in the hope of securing and extending her Mexican usurpation.  England was ready to give all the assistance in her power to any step which would weaken the North; and had the rebels been pressed back from the seaports and the Northern Atlantic slope, they would have had it in their power, if still holding the Mississippi, the South-west, including Tennessee, and the great natural fortresses of the mountains, to have so connected themselves with Mexico and France as to have caused the most serious embarrassment.  It became absolutely necessary to the success of the Government that the rebels’ northern line of defenses should be broken through, and that the Mississippi should be opened to its mouth.

At first, and before the nature of the work was fully understood, the whole was placed under the direction of the War Department, as it was thought the few armed transports which would be needed would be a mere appendage of the army.  The idea of a formidable river navy of a hundred powerful steamers did not in the beginning enter into the minds of any.

It was soon seen, however, that an entirely new description of craft was needed for this work.  It was clear that the river boats, which had been built for the common purposes of freight and passage, were not capable of resisting