John G. Nicolay, A Short Life of Abraham Lincoln, condensed from Nicolay and Hayes' Abraham Lincoln: A History

[286] arrived at Vicksburg on May 20. This city, by reason of the high bluffs on which it stands, was the most defensible point on the whole length of the great river within the Southern States; but so confidently had the Confederates trusted to the strength of their works at Columbus, Island No.10, Fort Pillow, and other points, that the fortifications of Vicksburg had thus far received comparatively little attention. The recent Union victories, however, both to the north and south, had awakened them to their danger; and when Lovell evacuated New Orleans, he shipped heavy guns and sent five Confederate regiments to Vicksburg; and during the eight days between their arrival on May 12 and the twentieth, on which day Farragut reached the city, six rebel batteries were put in readiness to fire on his ships.

General Halleck, while pushing his siege works toward Corinth, was notified as early as April 27 that Farragut was coming, and the logic of the situation ought to have induced him to send a cooperating force to Farragut's assistance, or, at the very least, to have matured plans for such cooperation. All the events would have favored an expedition of this kind. When Corinth, at the end of May, fell into Halleck's hands, Forts Pillow and Randolph on the Mississippi River were hastily evacuated by the enemy, and on June 6 the Union flotilla of river gunboats which had rendered such signal service at Henry, Donelson, and Island No.10, reinforced by a hastily constructed flotilla of heavy river tugs converted into rams, gained another brilliant victory in a most dramatic naval battle at Memphis, during which an opposing Confederate flotilla of similar rams and gunboats was almost completely destroyed, and the immediate evacuation of Memphis by the Confederates thereby forced.