At this moment, however, the brigades of Bee and Bartow--comprising the 7th and 8th Georgia, 2nd Mississippi, 4th Alabama, 6th North Carolina, and two companies of the 11th Mississippi, with Imboden's Battery of four pieces--recently arrived with Johnston from Winchester, come up, form on the right of Sloan's 4th South Carolina Regiment, while Wheat rallies his remnant on Sloan's left, now resting on the Sudley road, and the whole new Rebel line opens a hot fire upon Burnside's Brigade. Hunter, for the purpose of better directing the Union attack, is at this moment rapidly riding to the left of the Union line,--which is advancing Southwardly, at right angles to Bull Run stream and the old line of Rebel defense thereon. He is struck by the fragment of a shell, and carried to the rear. Colonel John S. Slocum's, 2nd Rhode Island, Regiment, with Reynold's Rhode Island Battery (six 13-pounders), having been sent to the front of Burnside's left, and being closely pressed by the Enemy, Burnside's own regiment the 1st Rhode Island, is gallantly led by Major Balch to the support of the 2nd, and together they handsomely repulse the Rebel onset. Burnside now sends forward Martin's 71st New York, with its two howitzers, and Marston's 2nd New Hampshire,--his whole Brigade, of four regiments and a light artillery battery, being engaged with the heavy masked battery (Imboden's and two other pieces), and nearly seven full regiments of the Enemy. The regiments of Burnside's Brigade are getting considerably cut up. Colonels Slocum and Marston, and Major Balch, are wounded. There is some confusion in the ranks, and the Rhode Island Battery is in danger of capture, when General Andrew Porter--whose own brigade has just reached the field and is deploying to the right of Burnside's--succeeds Hunter in command of the division, and rides over to his left. Burnside asks him for Sykes's battalion of regulars, which is accordingly detached from the extreme right of Andrew Porter's Division, rapidly forms on the left, in support of the Rhode Island Battery, and opens a hot and effective fire which, in connection with the renewed fire of Burnside's rallied regiments, and the opening artillery practice of Griffin's Battery--that has just come up at a gallop and gone into a good position upon an eminence to the right of Porter's Division, and to the right of the Sudley road looking South--fairly staggers the Enemy. And now the brigades of Sherman and Keyes, having been ordered across Bull Run by General Tyler, are seen advancing from Poplar Ford, at the rear of our left,--Sherman's Brigade, headed by Corcoran's 69th New York Regiment, coming up on Burnside's left, while Keves's Brigade is following, to the left again of, Sherman.