The boom of a heavy gun is heard from the centre. Carlisle has opened the ball. The day's work is begun. Another! The echoes spring from the hillsides all around, like a thousand angry tongues that threaten death. But on the right, no trace of an enemy is to be seen. Burnside's brigade was in the van; they reached the ford at Sudley's Springs; a momentary confusion ensues as the column prepares to cross. Soon the men are pushing boldly through the shallow stream, but the temptation is too great for their parched throats; they stoop to drink and to fill their canteens from the cool wave. But as they look up they see a cloud of dust rolling up from the plain beyond, and their thirst has passed away--they know that the foe is there. An aid comes spurring down the bank, waving his hand and splashing into the stream. "Forward, men! forward!" Hunter gallops to meet him, with his staff clattering at his horse's heels. "Break the heads of regiments from the column and push on--push on!" The field officers dash along the ranks, and the men spring to their work, as the word of command is echoed from mouth to mouth. Crossing the stream, their course extended for a mile through a thick wood, but soon they came to the open country, with undulating fields, rolling toward a little valley through which a brooklet ran. And beyond that stream, among the trees and foliage which line its bank and extend in wooded patches southward, the left wing of the enemy are in battle order. From a clump of bushes directly in front, came a puff of white smoke wreathed with flame; the whir of the hollow ball is heard, and it ploughs the moist ground a few rods from our advance. Scarcely had the dull report reverberated, when, in quick succession, a dozen jets of fire gleamed out, and the shells came plunging into the ranks. Burnside's brigade was in advance and unsupported, but under the iron hail the line was formed, and the cry "Forward!" was answered with a cheer. A long grey line spread out upon the hillside, forming rapidly from the outskirts of the little wood. It was the Southern infantry, and soon along their line a deadly fire of musketry was opened. Meanwhile the heavy firing from the left and further on, announced that the centre and extreme left were engaged. A detachment of regulars was sent to Burnside's relief, and held the enemy in check till a portion of Porter's and Heintzelman's division came up and pressed them back from their position.