Where the troops of General McClellan, waiting near the round-house at Alexandria, were hurried forward to the scene of action where Pope was struggling with Jackson and Ewell. Pope had counted upon the assistance of these reënforcements in making the forward movement by which he expected to hold Lee back. The old bogey of leaving the National Capital defenseless set up a vacillation in General Halleck's mind and the troops were held overlong at Alexandria. Had they been promptly forwarded, "Stonewall" Jackson's blow at Manassas Junction could not have been struck. At the news of that disaster the troops were hurriedly despatched down the railroad toward Manassas. But Pope was already in retreat in three columns toward that point, McDowell had failed to intercept the Confederate reënforcements coming through Thoroughfare Gap, and the situation had become critical. General Taylor, with his brigade of New Jersey troops, was the first of McClellan's forces to be moved forward to the aid of Pope. At Union Mills, Colonel Scammon, commanding the First Brigade, driven back from Manassas Junction, was further pressed by the Confederates on the morning of August 27th. Later in the day General Taylor's brigade arrived by the Fairfax road and, crossing the railroad bridge, met the Confederates drawn up and waiting near Manassas Station. A severe artillery fire greeted the Federals as they emerged from the woods. As General Taylor had no artillery, he was obliged either to retire or charge. He chose the latter. When the Confederate cavalry threatened to surround his small force, however, Taylor fell back in good order across the bridge, where two Ohio regiments assisted in holding the Confederates in check. At this point, General Taylor, who had been wounded in the retreat, was borne past in a litter. Though suffering much, he appealed to the officers to prevent another Bull Run. The brigade retired in good order to Fairfax Court House, where General Taylor died of his wounds a short time afterward. [Illustration: BRIGADIER-GENERAL GEORGE W. TAYLOR] [Illustration: AN UNREALIZED OPPORTUNITY] Here might have been won a Federal victory that would have precluded defeat at Second Bull Run. The corps of General Heintzelman, consisting of the divisions of Hooker and Kearny, was the next detachment of McClellan's forces to arrive to the aid of Pope. On the 28th of August, Heintzelman had pushed forward to Centreville, entering it soon after "Stonewall" Jackson's rear-guard had retired. Instead of pursuing, Heintzelman drew up his forces east of Cub Run, which we see in the picture. Jackson's forces, now in a precarious position, fell back toward Thoroughfare Gap to form a junction with Longstreet's Corps, which Lee had sent forward. The battle was commenced on the west somewhat feebly by Generals McDowell and Sigel. By nightfall the Confederate left had been driven back fully a mile. [Illustration: MAJOR-GENERAL SAMUEL P. HEINTZELMAN AND STAFF