He spoke in German, and both of the wounded men obeyed. Frank was immensely relieved. He had been afraid that they had been killed, and the thought had sickened him. He realized fully that it would have been in accordance with the idea of war had Greene killed them both; that it would have been no more than his duty. And yet he was more than glad that they were alive and, so far as he could judge at that moment, not badly hurt or not dangerously wounded, at least. "Fill that tank with the petrol," said Greene to Frank, "but leave a little in the can." Frank obeyed, wondering why the order was given. Then Greene pushed the monoplane along the ground for some distance until it was in a favorable position to take the air. "All right! Get in!" he said. "Strap yourself in. Know how the straps go? Right! I'm going to make a bonfire. It'll bring someone to help those poor chaps. I don't want them to have to lie here all night unless they have to." He took the can which Frank had almost emptied and poured what gasoline remained on the ground that had been protected from the rain by one wing of the monoplane. Then he flung a match into the now highly inflammable stubble, and a flame leaped up at once, lighting the monoplane and the two wounded Germans. In a moment more he was in his place and the monoplane was plunging along the ground. Then it took the air and rose swiftly to a safe height. And then for the first time there was a chance for explanations. "By Jove, how did you come to think of flashing that message to me?" cried Greene. "That was an idea! I almost gave it all away by answering before I realized what you were telling me. What was that fire I saw? Looked to me like the very place you said you were going to." So Frank explained. "Oh, splendid--my word, splendid!" cried Greene. "I fancy we'll find they've started this way already. Hullo--yes, by Jove, there come some of our fellows now! See, over there to the right? Aeroplanes--gone to spot those Johnnies. They didn't wait for us to come back!" He dropped to a bare hundred feet of elevation now and in a moment Frank could see why. Below them a mass of cavalry was in motion. "There they go!" cried Greene. "Your beacon gave them the line. The general must have decided that was confirmation enough." Now came a shouting from below, and Greene answered it by swooping down to a landing in the field. An officer put his horse to the wall and rode up beside them. "Captain Greene, by any chance?" he called, peering at them. "Yes, colonel," said Greene, saluting. "The Germans are in a clump of woods on the Amiens road. In an angle of that road and the one from LaFere, rather. I don't know the exact strength, but have reason to believe about five thousand." "There's no doubt about their being there, though?"