416. Lee's Second Invasion, 1863.--"Fighting Joe Hooker" was now in command of the Army of the Potomac. Outwitting Lee, he gained the rear of the Confederate lines on Marye's Heights, But Lee fiercely attacked him at Chancellorsville and drove him back across the Rappahannock. Then Lee again crossed the Potomac and invaded the North. This time he penetrated to the heart of Pennsylvania. Hooker moved on parallel lines, always keeping between Lee and the city of Washington. At length, in the midst of the campaign, Hooker asked to be relieved, and George G. Meade became the fifth and last chief of the Army of the Potomac. [Illustration: BATTLEFIELD OF GETTYSBURG, LOOKING SOUTH FROM ROUND TOP.] [Sidenote: Lee retires.] [Sidenote: Gettysburg, July 1-3, 1863.] 417. Gettysburg, July 1, 1863.--Meade now moved the Union army toward Lee's line of communication with Virginia. Lee at once drew back. Both armies moved toward Gettysburg, where the roads leading southward came together. In this way the two armies came into contact on July i, 1863. The Southerners were in stronger force at the moment and drove the Union soldiers back through the town to the high land called Cemetery Ridge. This was a remarkably strong position, with Culp's Hill at one end of the line and the Round Tops at the other end. Meade determined to fight the battle at that spot and hurried up all his forces. [Illustration: MAP: Battle of Gettysburg.] [Sidenote: The second day.] 418. Gettysburg, July 2, 1863.--At first matters seemed to go badly with the Union army. Its left flank extended forward from Little Round Top into the fields at the foot of the ridge. The Confederates drove back this part of the Union line. But they could not seize Little Round Top. On this day also the Confederates gained a foothold on Culp's Hill. [Sidenote: The third day. _Source-Book_, 323-327.] [Sidenote: Pickett's charge. _Hero Tales_, 227-236.] [Sidenote: It fails.] [Sidenote: Lee retreats, July 4, 1863.]