"General Tyler, the major-general has just learned that the enemy have crossed in force at Blackburn's Ford, below you. You are at once to take measures to protect your left flank." "Ah ha, Jack; Frederick's on the other side, eh?" Barney said, as, standing near the group, these words reached their ears. "Perhaps there are two Fredericks at work. Look yonder!" handing him his glass as he spoke. "Thunder! our whole army is marching over there to the right, and we sha'n't even see the battle. They are four miles off. Why, what an immense army we must have! I thought this was the bulk of it, but we're not a brigade compared to that." "Now, Barney, I feel confident that is the grand movement. Look how they fly along! The fields are as good as roads out there, and if it were not for the artillery they could make five miles an hour. Now, keep your ears open, my lad: you'll hear music off there to the northwest, music that will make Beauregard sick, if that courier's information is exact. For, don't you see, as we are placed here, with that gully to our left and the thick woods in front, we could hold this ground against six times our number." Company K were now sent forward to the right to relieve a body of skirmishers that had been hidden on the margin of Bull Run, some distance to the westward of the stone bridge. Jack, going forward with his glass, noticed an officer among the men, but not catching sight of his face did not recognize him. "Is that a rebel or one of our fellows?" one of the men said, pointing to a horseman disappearing in the woods four hundred yards to the right and in front of the company, marching in a straggling line two abreast, "by the flank," as it is called. Jack took his glass to discover, but the rider had disappeared. An instant after from a knoll, Jack, glass at eye, was examining eagerly the field on the other side of the river, when a horseman suddenly shot into view, riding desperately. "By George, it is the same man! I wonder how he crossed the stream? There must be a bridge down there among those thick trees and bushes," Jack said, excitedly. "Are you sure, sergeant, that is the same man that was in the woods to the right there, five minutes ago?" Jack turned; the officer was at his shoulder. He saluted respectfully, recognizing, with a thrill of joy, old Red Top, as the company called Sherman. "Yes, colonel, it's the same man. He was in his shirtsleeves and had a blue scarf tied about his arm. There can be no mistake; several of us saw him quite plainly." "If that be true, we've gained a half-day's work in two minutes." He was looking diligently through the glass as he spoke, and his eye brightened as he marked the man until he disappeared. He turned to an orderly that was following at a distance leading a horse. Mounting this lightly the colonel rode to the head of the company and said in a short, decisive tone: