“They’ll be back,” prophesied Frank, for he could see the enemy in the shelter of the woods trying to reform. “This place is too important to give it up without another try. How’s the ammunition holding out?” “Plenty yet,” replied Billy. “There must be a thousand rounds. And the best of it is that they’re German bullets out of a German gun that we’re feeding to Fritz.” “Shows how honest we are,” chuckled Tom. “We’re giving him all that belongs to him. And we’re giving it to him too with compound interest.” Once more the Germans came on, only to be mowed down like corn before the reaper. The boys had thrown off all their upper garments now and were stripped to the waist, for the confined quarters of the tank and the heat of the firing were causing the perspiration to run down their faces and bodies in streams. Suddenly Tom gave a cry of alarm. “The gun’s getting too hot!” he exclaimed. “It blisters you when you touch it. We’ll have to give it a rest and let it cool off.” “Rest nothing,” declared Frank, as he saw that the Germans were trying to advance. “They’d be on us before we’d be ready to fire again. Quick, you fellows, get your canteens and pour the water into the cooler of the gun. That’ll keep it going so that we can use it.” In a twinkling his comrades obeyed, and every drop that their canteens contained was emptied into the cooler. The result was apparent at once, and the gun continued its deadly work without interruption. But now the Germans had brought up a field-piece and placed it in position where it had a good target in the tank, and shells began to fall thick and fast in the vicinity of their temporary fort. It was evidently only a matter of time before one of them would strike it and put it out of business. “Getting pretty hot,” muttered Frank, as one shell fell within twenty feet and a great volume of smoke and dirt rolled over them. “Can’t you pick off the gunners, Frank?” asked Billy. “I’m trying to,” answered Frank, “but the bullets fall short. Those fellows are too far out of range.” As he spoke, there was a roar that almost split their eardrums and a shell exploded within a few feet of the tank. It dug a great crater under one edge of the tank which began to topple ominously. “Jump!” shouted Frank, and they leaped out just as the tank lurched over and tumbled into the hole. They were just in time, for in another instant the monster would have carried them with it and probably caught them beneath its weight. As it was, Tom’s leg was badly scraped by one of the edges as it passed him. CHAPTER XIII THE WHITE FLAG OF SURRENDER The Germans sent up a triumphant shout as they saw the tank go over, and a large detachment came rushing out of the woods. But by the time they had advanced a few yards, Frank and his squad grabbed their rifles, and, crouching behind what shelter they could find, sent a volley of bullets into the enemy ranks.