ing the front wider and wider like a fan, resulted in loss of cohesion between the divisions, brigades, and regiments. The advantage of continuous unity of command was also wanting. It cannot be said that the army as a whole had the benefit of intelligent general direction at any time during the day. The division and brigade commanders and even partly the regimental commanders were left to their own devices. Much of this lack of guidance and the consequent confusion was due to the early compulsory retirement of Brigade-Commander Hunter from the field upon receiving a severe wound. Moreover, owing to the fatigue of the troops, who had been on their feet since midnight, and their exhaustion from the intense July heat, more and more men lagged behind as the forward movement proceeded, and the temporary success in the noon hour was probably achieved by less than two-thirds of the effective force that had set out from Centreville. Deducting the killed, wounded, and disabled, the stragglers and skulkers, from the effective number of the two and one-half divisions (Hunter's and Heintzelman's, with Sherman's brigade) at the start, doubtless only about ten thousand Unionists remained confronting the enemy at one o'clock, and they were drawn out on a long, irregular, and barely connected line, and were tired and suffering from hunger and thirst. Nor was there any reserve available to make up for the depletion of their ranks.
Only Beauregard's left flank, with the four regiments from the Shenandoah Valley, had so far been engaged. In falling back before the Union troops, it had reached a strong position on a wooded plateau commanding the lower ground over which the Federals would have to pass in pushing their attack. Here both the rebel commanders, Johnston and Beauregard, themselves took charge. They were now convinced that there the main effort of the Federals was being made, and that no other part of their line was actively endangered. So they ordered regiments from their centre and right to the threatened position. Most
