Generals Pendleton and Alexander, chiefs of artillery of the Army of Northern Virginia and of Longstreet's corps, respectively, massed 150 guns on a ridge extending generally parallel to the left of the Union Army and about one mile therefrom, and so as to be able to pour a converging fire on its left centre.(10) While this preparation for decisive battle went on in the Confederate lines, the Union Army stood at bay, in readiness for the battle-storm foreboded by the long lull and the active preparations observed in its front. At 1 P.M. Longstreet's batteries opened, and the superior guns of the Union Army, though not in position in such great number, promptly responded. This terrific duel lasted about two hours. Meade, recognizing the futility of his artillery fire, and in anticipation of the assault soon to come, ordered a large portion of his artillery withdrawn under cover, to give the guns time to cool and to be resupplied with ammunition. This led the enemy to believe he had silenced them effectively, and the assaulting column went forward.(11) The Union artillery, with fresh batteries added, was again quickly put in position for its real work. The close massed column of assault, well led, gallantly moved to the charge down the slope and across the open ground, directed against a portion of the Union line partially on Cemetery Ridge. The supporting Confederate batteries now almost ceased firing. As the assaulting column went forward the Union guns turned on it, cutting gaps in it at each discharge. These were generally closed from the support, but when the head of the column got well up to, and in one place into, the Union breastworks, the fire of the Union infantry became irresistible. Longstreet ordered the divisions of McLaws and Hood, holding his line on the right of the assaulting column, to advance to battle. Union forces moved out and attacked Pickett's supporting brigade on the right. Under the fierce fire of infantry and artillery the head of the great Confederate column fast melted away. Generals Garnett, Pender, Semmes, Armistead, and Barksdale were killed, Generals Kemper, Trimble, Pettigrew, and many other officers fell wounded, and many Confederate colors were shot down. The Confederates who penetrated the Union line were killed or captured. When success was demonstrated to be impossible, Pickett ordered a retreat, and such of his men as were not cut off by the fire that continued to sweep the field escaped to cover behind the batteries, leaving the broad track of the assaulting column strewn with dead, dying, and wounded. The great battle was now substantially ended. Meade did not draw out his army and pursue the broken Confederates, as their leaders expected him to do. Lee, while personally aiding in restoring the lines of his shattered troops, recognized the fearful consequences of Pickett's assault, and magnanimously said to an officer, "_It is all my fault_."