395. Fredericksburg, December, 1862.--Burnside found Lee strongly posted on Marye's Heights, which rise sharply behind the little town of Fredericksburg on the southern bank of the Rappahannock River. Burnside attacked in front. His soldiers had to cross the river and assault the hill in face of a murderous fire--and in vain. He lost thirteen thousand men to only four thousand of the Confederates. "Fighting Joe" Hooker now succeeded Burnside as commander of the Army of the Potomac. We must now turn to the West, and see what had been doing there in 1861-62. [Sidenote: General Grant.] [Sidenote: He seizes Cairo.] [Sidenote: Battle of Mill Springs, January, 1862.] 396. Grant and Thomas.--In Illinois there appeared a trained soldier of fierce energy and invincible will, Ulysses Simpson Grant. He had been educated at West Point and had served in the Mexican War. In September, 1861, he seized Cairo at the junction of the Ohio and the Mississippi. In January, 1862, General George H. Thomas defeated a Confederate force at Mill Springs, in the upper valley of the Cumberland River. In this way Grant and Thomas secured the line of the Ohio and eastern Kentucky for the Union. [Illustration: THE BRIDGE AT ANTIETAM. Burnside's soldiers charged over the bridge from the middle foreground.] [Sidenote: Capture of Fort Henry, February, 1862.] [Sidenote: Fort Donelson.] 397. Forts Henry and Donelson, February, 1862.--In February, 1862, General Grant and Commodore Foote attacked two forts which the Confederates had built to keep the Federal gunboats from penetrating the western part of the Confederacy. Fort Henry yielded almost at once, but the Union forces besieged Fort Donelson for a longer time. Soon the Confederate defense became hopeless, and General Buckner asked for the terms of surrender. "Unconditional surrender," replied Grant, and Buckner surrendered. The lower Tennessee and the lower Cumberland were now open to the Union forces. [Sidenote: The lower Mississippi.] [Sidenote: Admiral Farragut.] 398. Importance of New Orleans.--New Orleans and the lower Mississippi were of great importance to both sides, for the possession of this region gave the Southerners access to Texas, and through Texas to Mexico. Union fleets were blockading every important Southern port. But as long as commerce overland with Mexico could be maintained, the South could struggle on. The Mississippi, too, has so many mouths that it was difficult to keep vessels from running in and out. For these reasons the Federal government determined to seize New Orleans and the lower Mississippi. The command of the expedition was given to Farragut, who had passed his boyhood in Louisiana. He was given as good a fleet as could be provided, and a force of soldiers was sent to help him. [Illustration: A RIVER GUNBOAT.] [Sidenote: Capture of New Orleans, April, 1862. _Higginson_, 303-304; _Source-Book_, 313-315.]