Some of the subordinate commanders retire gloomily to their commands. They disagree in opinion with their commander. They believe that the hour has come when the decisive blow can be given. As good soldiers, it is their duty to obey; but they sit down by the fence in the edge of the woods, dissatisfied with the decision of General McClellan. The reserve artillery is in the field northeast, a few rods distant,--a hundred guns. They believe that the time has come to use it. They do not like the plan of fighting in detachments--Hooker in the morning--then Mansfield--then Sedgwick's division--then French, and Richardson, and Burnside--who is separated from the main army, and has a hard task assigned him. During the afternoon, the Rebels made a demonstration on the right by Poffenberger's. It was done to cover up their real intentions. I was talking with General Howard when an officer dashed up. "The Rebels are advancing to attack us," said he. "Let them have the heaviest fire possible from the batteries," was the reply. As I rode towards the batteries on the ridge by Poffenberger's, thirty guns opened their brazen lips, each piece speaking three times a minute. The dark gray masses, dimly discerned through the woods and among the tasseled corn, wavered, staggered, reeled, swayed to and fro, advanced a few steps, then disappeared. GENERAL BURNSIDE'S ATTACK. General Burnside's task was the hardest of all. The banks of the river by the lower bridge are steep and high, and the land on both sides is broken. The road leading to the bridge winds down a narrow ravine. The bridge is of stone, with three arches. It is twelve feet wide, and one hundred and fifty feet long. The western bank is so steep that one can hardly climb it. Oak-trees shade it. Half-way up the hill there is a limestone quarry,--excavations affording shelter to sharpshooters. At the top there is a stone wall, a hundred feet above the water of the winding stream, and yet so near that a stone may be thrown by a strong-armed man across the stream. A brigade of Rebels, with four pieces of artillery, guarded the bridge. There were sharpshooters beneath the willows, and in the thick underbrush along the bank of the stream. There were riflemen in the excavations on the hillside and behind the trees. The four cannon were behind the wall, with the great body of infantry in support. The bridge, the hills and hollows on the eastern bank, are raked and searched in every part by the infantry. South of Sharpsburg there are numerous batteries ready to throw solid shot and shells over the heads of the brigade by the bridge. If Burnside carries the bridge, there are the heights beyond, the ground in front all open, swept and enfiladed by batteries arranged in a semicircle, supported by A. P. Hill's and a portion of Longstreet's troops. A. P. Hill was not on the ground in the morning, but arrived while the battle was in progress on the right and center.