Now beneath the helmet the head of a man appeared, then the shoulders, and finally the sentry, evidently satisfied that his suspicion had been without foundation, straightened out to his full length. He stood for another minute or two peering into the darkness. But Frank's black-clad form merged so perfectly into its surroundings and he remained so motionless that the German at last was convinced. With a grunt of satisfaction he stooped to pick up his rifle. Lithe as a panther, Frank sprang to his feet, leaped over the hedge and landed heavily on the stooping form, knocking the breath out of the German's body. In a flash Frank's sinewy hands were upon the sentry's throat, stifling the cry that sought to issue from his lips. There was a brief struggle, but the attack had been so sudden and tremendous that it was soon over, and the German lay limp and unconscious. The instant Frank realized this, he relaxed his hold. He tore open the man's coat, felt for his heart and found that it was still beating. What his foe would have done if the case had been reversed, Frank knew perfectly well. A dagger point would have pierced his heart and stilled its beating forever. More than once he had looked on the bodies of comrades who had been butchered while lying wounded and helpless on the battlefield, and had been stirred by a wild desire to take similar vengeance on those who had violated all the laws of war. But he was an American, with all the proud traditions of honor and chivalry that had come down to him through generations. He could not slaughter a helpless foe. He had the man a prisoner. It was enough. Quickly he tied the sentry's hands, using the German's own belt as a strap. Then he tore some strips from the white cloth he had been carrying to fasten on the bushes and made a gag, in case the man should recover his senses and try to give the alarm. He dragged the man through a gap in the hedge so that he would not be found by any of his comrades who might come that way. Then he crept down to where the corporal and the other members of the patrol were still busy on the wires and in a whisper told what had happened. Wilson was quick to see the opportunity that the capture had afforded. "Good work, Sheldon," he commended. "Here's where we get through the wires. And we've got to do it quickly, for we don't know at what time that fellow's relief may be coming along." His prophecy seemed about to be fulfilled with startling suddenness, for, even while he spoke, a group of several figures, topped by helmets, was revealed by the action of one of them in striking a match. It flared up brightly for a second, but luckily the boys were outside the zone of light that it formed. They lay perfectly still, although each of them took a tighter grasp on his rifle. The men conversed in guttural tones for several minutes, that seemed as many ages to the watchers in the shadows.