The Confederates were of course set on recovering complete control of the line of Southern rails that made direct connections between the Mississippi Valley and the sea: crossing the western tributaries of the St. Francis and White Rivers; then running east from Memphis, through Grand Junction, Corinth, and Iuka, to Chattanooga; thence forking off northeast, through Knoxville, to Washington, Richmond, and Norfolk; and southeast to Charleston and Savannah. Confederate attention had originally been fixed on Corinth and Chattanooga. But General O. M. Mitchel's abortive raid, just after Shiloh, had also drawn it to the part between. The Federals therefore found their enemy alert at every point. Braxton Bragg, Beauregard's successor and Buell's opponent, basing himself on Chattanooga, tried to drive his line of Confederate reconquest through the heart of Tennessee and thence through mid-Kentucky, with the Ohio as his ultimate objective. His colleagues near the Mississippi, Van Dorn and Sterling Price, meanwhile tried to effect the reconquest of the Memphis-Corinth rails that Grant and Rosecrans were holding. All main offensives, on both sides, ultimately failed in this latter half of the river campaign of '62. So nothing but the bare fact that they were attempted needs any notice here. In August, about the time that Lee and Jackson were maneuvering in Virginia to bring on the Second Bull Run, Price and Bragg began their respective advances against Grant and Buell. Buell was at Murfreesboro, defending Nashville. Bragg, screened by the hills of eastern Tennessee, made for the Ohio at Louisville and Cincinnati. Pivoting on his left he wheeled his whole army round and raced for Louisville. Buell enjoyed the advantage of rails over roads and of interior lines as well. But Bragg had stolen several marches on him at the start and he only won by a head. The Union Government, now thoroughly alarmed, sent Thomas to supersede Buell. But Thomas declined to take over the command, and on the eighth of October Buell fought Bragg at Perryville. There was no tactical defeat or victory; but Bragg retired on Chattanooga. The Government now urged Buell to enter east Tennessee. He protested that lack of transport and supplies made such a move impossible. William S. Rosecrans then replaced him. Buell was never employed again. He certainly failed fully to appreciate the legitimate bearing of statesmanship on strategy; but, for all that, he was an excellent organizer and a good commander. In the meantime Grant had been experiencing his "most anxious period of the war." During this anxious period, which lasted from July to October, Rosecrans defeated Price at Iuka. This happened on the nineteenth of September. Van Dorn then joined Price and returned to the attack but was defeated by Rosecrans at Corinth on the fourth of October. The Confederates, who had come near victory on the third, retired in safety, because Grant still lacked the means of resuming the offensive.