It must also be observed that not only was this line of communications four times as long as that which led from the sea to New Orleans, and of far more difficult pilotage, but that the natural character of the enemy's positions upon it was essentially different. They were as yet undeveloped by art; but by nature they were high and commanding bluffs, having secure land communications with an extensive enemy's country in their rear over which our troops exercised no control whatever--where they had not even been seen. To speak of "taking them in the rear" was to beg the question--to assume that their front was then, as in June, 1863, toward an enemy investing them on the land side. New Orleans and the region below, including its defenses and the communications therewith, were low-lying and intersected with numerous water-courses; over such a navy naturally exercises a preponderating control. Above New Orleans the low delta of the Mississippi extends, indeed, on the west bank as far as the Red River, if it may not be said to reach to Vicksburg and beyond; but on the east bank it ceases one hundred and fifty miles from the city. From thence to Vicksburg, a distance of two hundred and fifty miles, the stream is bordered by a series of bluffs backing on a firm country of moderate elevation. Such positions are not to be reduced from the water alone. On the contrary, if the water be a narrow strip swept by their guns, they command it; while, from the extent of country in their rear, they are not susceptible of isolation by fleets above and below, as were Forts Jackson and St. Philip. This series of bluffs became, therefore, the line upon which the Confederates based their control of the Mississippi and maintained their vital communications with Texas and the Red River region. It could be reduced only by a military force; and to think of subduing it by a fleet taking advantage of the panic following the fall of New Orleans, was truly to rely upon moral effect without adequate physical force to support it. It is due to the Navy Department to say that they expected the army from the North to advance more rapidly than it did; but, without seeking to assign the blame, the utterly useless penetration of the United States fleet four hundred miles into the heart of the enemy's country and its subsequent mortifying withdrawal, when contrasted with the brilliant success resulting from Farragut's dash by the forts, afford a very useful lesson in the adaptation of means to ends and the selection of a definite objective, upon compassing which something happens. The object of the United States Government being to control the lower Mississippi, that was effected by means of isolating its defenses, which then fell. When the further object was sought of controlling the course of the stream above, the mere perambulation of a body of ships effected nothing, because it aimed at nothing in particular, and could have no effect upon the decisive points.