During the afternoon, the Confederate attack upon Hancock's and Burnside's forces, which constituted nearly half the entire army, was so severe that the Federal lines began to give way. The combatants swayed back and forth; the Confederates seized the Federal breastworks repeatedly, only to be repulsed again and again. Once, the Southern colors were placed on the Union battlements. A fire in the forest, which had been burning for hours, and in which, it is estimated, about two hundred of the Federal wounded perished, was communicated to the timber entrenchments, the heat and smoke driving into the faces of the men on the Union side, and compelling them in some places to abandon the works. Hancock made a gallant and heroic effort to re-form his lines and push the attack, and, as he rode along the lines, his inspiring presence elicited cheer upon cheer from the men, but the troops had exhausted their ammunition, the wagons were in the rear, and as night was approaching, further attack was abandoned. The contest ended on the lines where it began. Later in the evening consternation swept the Federal camp when heavy firing was heard in the direction of Sedgwick's corps, on the right. The report was current that the entire Sixth Corps had been attacked and broken. What had happened was a surprise attack by the Confederates, commanded by General John B. Gordon, on Sedgwick's right flank, Generals Seymour and Shaler with six hundred men being captured. When a message was received from Sedgwick that the Sixth Corps was safe in an entirely new line, there was great rejoicing in the Union camp. Thus ended the two days' fighting of the battle of the Wilderness, one of the greatest struggles in history. It was Grant's first experience in the East, and his trial measure of arms with his great antagonist, General Lee. The latter returned to his entrenchments and the Federals remained in their position. The first clash had been undecisive. While Grant had been defeated in his plan to pass around Lee, yet he had made a new record for the Army of the Potomac, and he was not turned from his purpose of putting himself between the Army of Northern Virginia and the capital of the Confederacy. During the two days' engagement, there were ten hours of actual fighting, with a loss in killed and wounded of about seventeen thousand Union and nearly twelve thousand Confederates, nearly three thousand men sacrificed each hour. It is the belief of some military writers that Lee deliberately chose the Wilderness as a battle-ground, as it would effectually conceal great inferiority of force, but if this be so he seems to have come to share the unanimous opinions of the generals of both sides that its difficulties were unsurmountable, and within his entrenchments he awaited further attack. It did not come.