He had not long to wait. A whistle sounded shrilly. The men dashed from the cover of the bushes and poured up towards the tower, shouting and cheering. Behind them their comrades opened fire from the rocks. Burton held his hand for a few seconds. Then, when the foremost rank had covered about half the distance, the machine-gun rapped out a hail of bullets. In a few seconds the track was swept clear as by an invisible scythe. Silence fell again. It was clear that the enemy had not reckoned with a machine-gun, for though, taking advantage of the charge, another body of men had rushed up to the bushes from the rear, they made no attempt to advance farther. Minute by minute passed. Except for occasional sniping, the enemy took no action. But the lull seemed ominous, and Burton remained keenly on guard, keeping a look-out from behind the shield of the machine-gun. "I don’t like it," he said to Enderby once. "There isn’t much doubt that they have sent word to their gunners, and we shall soon have shells hurtling upon us. There may be just time to carry you down and put you in safety beyond the tower." "Nonsense!" Enderby returned. "It makes me sick to be idling here. I won’t go and keep your Germans company. My arms are sound enough, and, hang it all! I won’t stand this any longer. Lift me out, and give me a rifle." "No, no! Anything rather than that. At this window you’d be potted to a certainty. Perhaps it’s better as it is, for if you were outside, and the rest of us were smashed, you couldn’t get away." "And I’d rather peg out than fall a prisoner to those German-led Bulgars. Don’t worry, old chap!" "That wretched mine must have failed," said Burton, presently. "Nuta must go and relight the train." But just as he was rising to call her, he noticed something far down the track that caused him to drop back again. "They’re smuggling a machine-gun into position!" he cried. He had caught a glimpse of the barrel projecting over a ledge of rock. With instant decision he trained his own gun upon it, and before it could open fire, he pumped out a hail of lead that struck it from its position, and the men serving it, in spite of their shield, were killed or disabled either by direct shots, ricochets, or splinters. "One belt empty!" he said, as he replaced it with a full one. "By George! Now we’re in for it!" He had heard the characteristic scream of a shell. Immediately afterwards there was a terrific explosion, and he saw a tall column of smoke, stones, and dust shoot into the air from the rocks not two hundred yards away. In another half-minute another shell exploded, a little nearer. "They must be ’phoning the range," he said. "Look here, Enderby, I must get you out of it. I can’t leave the machine-gun now, but the Serbs must carry you away. Marco Kralevich!" he shouted. The old man hurried down.