"This startled me, you may be sure. 'Up, up!' I shouted. The machine obeyed. We rose to an altitude of eight hundred meters, then suddenly the engine stopped. My assistant turned and shouted: 'We have no petrol.' I crawled back and tested the tank. It was empty. 'Volplane to the south,' I said. It was the only thing I could do. Now that the engine was silent the sounds from the earth were startling. There was terrific firing to the right and left, and all about us; but we must go down; there was no help for that. "Soon the earth again came in sight, and then the location of the batteries was made out by the volumes of smoke, which could be seen at each volley. My assistant tried to hold up the machine as long as possible, but we were now down to 300 meters, then the barometer registered 250. We both noticed a large, apparently smooth field, and the final volplane began. We landed a hundred feet from a first-line trench, and although the Germans made it hot for us for about fifteen minutes we were soon able to reach the laterals and thus escape their fire. But the machine was in a bad condition when we rescued it that night. It was literally shot full of holes. What is left of it is now in the end warehouse where the scraps are kept." CHAPTER IX A CHAPTER OF LESSONS ABOUT THE AEROPLANE Early the following morning there was intense activity in the camp, and Ralph was among the first to learn the cause of the excitement. Several army divisions had come up in the night, and were bound for the Verdun sector, and from the information obtained it was the intention of the commander to make a terrific assault in order to break the German lines north of the city. The lieutenant, when approached, admitted that they were now in for double duty. "Every man in the corps must report and be ready in the morning. There will be two days of observation, and then look out for some business." "When will we go to Verdun?" asked Ralph. "We are expecting orders at any moment," was the reply. During the previous afternoon more than fifty machines had assembled, and some of those were now leaving, a few going directly east, on observation tours, while others were circling about and testing the engines. "I am expecting a big Farman machine," said Lieutenant Guyon, as he returned from headquarters an hour afterwards, "that is equipped for carrying bombs, but I am told it is one of the speediest machines in the service. It will easily carry six hundred kilos in bombs (1,200 pounds), and we are ordered to wait here until it arrives." When the boys were alone, Alfred, with a glint of joy in his eyes, remarked: "I think that will give us an opportunity to do some flying with the lieutenant." "Do you think so?" replied Ralph, elated at the thought. "I am sure of that," said a voice behind them. They quickly turned and saw the lieutenant, who had entered unobserved. They saw by the smile on his face that the remark was an agreeable one, for he continued: