Corinth was of immense importance to both sides, as it commanded the rails not only east and west, from the Tennessee to Memphis, but north and south, from the Ohio to New Orleans and Mobile. Though New Orleans was taken by Farragut on the twenty-fifth of April, the rails between Vicksburg and Port Hudson remained in Confederate hands till next year; while Mobile remained so till the year after that. Beauregard collected all the troops he could at Corinth. Yet, even with Van Dorn's and other reinforcements, he had only sixty thousand effectives against Halleck's double numbers. Moreover, the loss of three States and many battles had so shaken the Confederate forces that they stood no chance whatever against Halleck's double numbers in the open. All the same, Halleck burrowed slowly forward like a mole, entrenching every night as if the respective strengths and victories had been reversed. After advancing nearly a mile a day Halleck closed in on Corinth. He was so deeply entrenched that no one could tell from appearances which side was besieging the other. Towards the end of May many Federal railwaymen reported that empty trains could be heard running into Corinth and full trains running out. But, as the Confederates greeted each arriving "empty" with tremendous cheers, Halleck felt sure that Beauregard was being greatly reinforced. The Confederate bluff worked to admiration. On the twenty-sixth Beauregard issued orders for complete evacuation on the twenty-ninth. On the thirtieth Halleck drew up his whole grand army ready for a desperate defense against an enemy that had already gone a full day's march away. In the meantime the Federal flotilla had been fighting its way down the Mississippi, under (the invalided) Foote's very capable successor, Flag-Officer Charles Henry Davis. The Confederates had very few naval men on the river, but many of their Mississippi skippers were game to the death. They rammed Federal vessels on the tenth of May at Fort Pillow, eighty miles above Memphis. Eight of their fighting craft were strongly built and heavily armored, though very deficient in speed. The Federal flotilla was very well manned by first-class naval ratings, and was reinforced early in June by seven fast new rams, commanded by their designer, Colonel Charles Ellet, a famous civil engineer.