At about three o'clock the Union army saw with astonishment, not unmixed with dismay, the whole of the Third Corps moving out to the front in magnificent order, not as troops go into battle with skirmishers well advanced to the front, but as confidently as if going to a review with two grand armies for spectators. It was indeed a gallant sight to see these solid columns go forward, brigade after brigade, battery following battery, as, with flags fluttering in the breeze and bayonets flashing in the sun, the two divisions of Humphreys and Birney began deploying along the Emmettsburg road in front and taking position between the peach orchard and the Devil's Den to their rear, thus putting an elbow in the general line. In vain we try to imagine one of Napoleon's or Wellington's marshals taking it upon himself to post his troops independently of his commander. It now appears that General Sickles did this regardless of whether he was thwarting the plans of the general-in-chief or not, or whether indeed by so doing he was overthrowing the whole theory of delivering a strictly defensive battle. Instead of allowing Meade his initiative, we find Sickles actually compelling his superior to follow his lead,[61] not under the stress of some sudden emergency, but deliberately, defiantly. Not that he had penetrated Lee's designs. By no means. Had he done so we should be all the more amazed at his hardihood in going out with his ten thousand men to resist the onslaught of twenty thousand or more. But the whole corps was not enough to occupy the ground selected. When the right division (Humphreys') reached the road, it had left a space of not less than three-fourths of a mile between itself and the left of the Second Corps. That flank was therefore in the air. The left division (Birney's), or most of it, was formed nearly at right angles with the first, showing a front of three brigades facing south, and posted in a line much broken by the natural features of the ground, which grow more and more rugged in proportion as Round Top is neared. Though stronger, by reason of the natural defences, this flank was a fourth of a mile from Round Top. While this was going on out at the front, the Sixth and last Union Corps (Sedgwick's) was coming up behind the main position, worn down with marching thirty-six miles almost without a halt. The Fifth had already arrived, also with its men greatly fatigued. The situation, therefore, had so far improved, in that the enemy's delays[62] had given time for the whole Union army to assemble, though the two belated corps were scarcely in fighting trim. Scarcely had Birney's men time to look about them when the booming of a single gun gave notice that the long-expected battle had begun.