The unaccountable inertness of the Eastern army of the Union, under McClellan, gave them time to strengthen their defences, and reinforce their army, which had dwindled to a very low ebb during the winter. But while the commander of the East was planning strategy that, by the slowness of its development, if by nothing _worse_, was destined to dim the lustre of the Union triumphs, and lose the results of a year of war, the West was in motion. Down the Mississippi swept our invincible fleet, with an army on shore to second its operations. Up the Tennessee steamed Grant's victorious army, and Buell, with forty thousand men, was marching across the State of Tennessee, to reach the same point. My own division, under the lamented General O. M. Mitchel, was also marching across the State, but in a different direction, having Chattanooga as its ultimate aim, while Morgan, with another strong force, many of whom were refugees from East Tennessee, lay before Cumberland Gap, ready to strike through that fastness to Knoxville, and thus reach the very heart of rebellion.
To meet these powerful forces, whose destination he could not altogether foresee, Beauregard, who commanded in the west, concentrated his main army at Corinth, with smaller detachments scattered along the railroad to Chattanooga. The railroads on which he relied for supplies and reinforcements, as well as for communication with the eastern portion of rebeldom, formed an irregular parallelogram, of which the northern side extended from Memphis to Chattanooga, the eastern from Chattanooga to Atlanta, the southern from Atlanta to Jackson, Mississippi, and the western, by a network of roads, from Jackson to Memphis. The great East Tennessee and Virginia Railroad, which has not inaptly been called "the backbone of the rebellion," intersected this parallelogram at Chattanooga. Thus it will be seen that to destroy the northern and eastern sides of this parallelogram isolated Beauregard, and left East Tennessee, which was then almost stripped of troops, to fall easily before General Morgan.
So important was this destruction of communication deemed by those in power, that it was at first intended to reach both sides, and destroy them by armies; but the distance was so great that the design of destroying it in this manner was abandoned.