They heard a roar and hiss a minute later, and a shell burst inside the walls. Through all the afternoon Carrington played upon the shaken nerves of the Invincibles. It seemed that he could make his shells hit wherever he wished. If a recruit left a trench it was only to make a rush for another. If their nerves settled down for a moment, that solemn boom from the forest and the shriek of the shell made them jump again. "Wonderful! Wonderful!" murmured Colonel Talbot, "but terribly trying to new men! Carrington certainly grows better with the years." Harry tried to compose himself and rest, as he lay in the trench with St. Clair and Langdon. They had had their battle face to face and all three of them were terribly shaken, but they recovered themselves at last, despite the shells which burst at short but irregular intervals inside the fort. Thus the last hours of the afternoon waned, and as the twilight came, they went more freely about the fort. Colonel Talbot called a conference of the senior officers in a corner of the enclosure well under the shelter of the earthen walls, and after some minutes of anxious talking they sent for the three youths. Harry, St. Clair and Langdon responded with alacrity, sure that something of the utmost importance was afoot. CHAPTER XIII THE SEEKER FOR HELP Colonel Talbot, Lieutenant-Colonel St. Hilaire and four other officers were in a deep alcove that had been dug just under the highest earthwork, where they were not likely to be interrupted in their deliberations by any fragment of an exploding shell. The only light was that of the stars and the early moon which had now come out, but it was sufficient to show faces oppressed by the utmost anxiety. Three other men also had been summoned to the council. "We have chosen you six for an important errand," said Colonel Talbot, "but you are to go upon it singly, and not collectively. As you see, we are besieged here by a greatly superior force. Its assault has been repulsed, but it will not go away. It will bombard us incessantly, and, since we are not strong enough to break through their lines and have limited supplies of food and water, we must fall in a day or two, unless we get help. We want you to make your way over the hills tonight to General Beauregard's army and bring aid. Even should five be captured or slain the sixth may get through. Lieutenant Kenton, you will go first. You will recall that the horses of the officers were left on the crest of the mountain with a small guard. They may be there yet, and if you can secure a mount, so much the better. But the moment you leave this fort you must rely absolutely upon your own skill and judgment." Harry bowed. It was a great trust and he felt elation because he had been chosen first. He was again a courier, and he would do his best.