Four hundred miles, that was the distance of the double journey. Two hundred miles of enemy territory to be traversed before they reached their objective; then, another two hundred back again to safety; and no chance of a landing to remedy even the slightest defect. That was the prospect before these daring aviators, as they sallied forth on their dangerous errand this morning about half an hour before the first faint whisper of dawn came up out of the east. No wonder the Commanding Officer of the Squadron, as he watched them depart, turned to his companions and said: "A perilous venture, isn't it, for the boys?" "You're right, sir," replied the orderly officer. "I hope not one of them will lose the number of his mess before nightfall." "Ah, well. We have had some vacant chairs in the mess lately. Four hundred miles," he was heard to remark as he turned on his heels and went back to his room. He was a kindly, considerate commander, for he had that rare quality which combined firmness with kindness, and because of that he was loved by all his men. The adventurers crossed the German lines at seven thousand feet, and in the darkness the enemy's searchlights failed to find them, so they were well away for once. There was just a little doubt in Dastral's mind about the weather conditions when he started, as the success of the venture depended very much upon the visibility. At present, however, the dull cloudy weather was in their favour, if only it might clear up later. He was therefore very pleased when, having left the enemy's lines some thirty or forty miles behind, the first tinge of dawn lit up the sky in front of them, showing the horizon clearly. The wind had changed during the last hour, and, though it grew colder, it became much brighter. Once or twice the Flight-Commander looked round at his followers, casting a critical eye upon the whole flight. "Thank goodness, the engines seem to be running well. Everything depends on them," he murmured. His own machine was a double-seater type with the observer's car projecting right in front of the engine, a powerful twelve-cylindered R.A.F. A little later Jock, speaking through the tube, shouted: "Shots on the left, Dastral!" and he pointed to a spot far down below, for the landscape had opened out now, and they had been spotted for the first time. Dastral looked down, and saw several rapid flashes, away down on the left, where a battery of "Archies," having found them, had opened fire. In front of the machine which was leading the flight, Dastral saw several black bursts of smoke, and in the centre of each burst was a yellow glare. "Ah, the Boches have found the range to a nicety!" yelled Dastral to Jock. "Look out! We must dive." Then, pulling over the controls, the hornet dipped at the head, doing a neat little nose-dive of some five hundred feet, throwing the enemy's range out of gear, and compelling him to readjust his sights.