Simultaneously, the air mechanics sprang to attention, as they stood about the hornet. Then, after a couple of minutes spent in chatting with the adventurers, who were about to sail forth on the wings of the morning, the O.C. and the pilot flung away their cigarettes and gave a few apparently casual glances over the framework by the aid of the hand-lamps. "Better load up with a few twenty pound bombs, Dastral," laughed the O.C. "You may have the chance of using one going over seas. You never know your luck." "Yes, sir," replied the youth. A moment later the pilot and observer were seated in the biplane, snugly wrapped in their thick leather coats, their hands encased in huge gauntlets, and their helmets tightly drawn about their ears, ready for the morning adventure. Dastral gave a final glance around, his hand already on the controls, then gave a nod to the chief of the ground staff. "Swing the propellor!" came next, followed by "Stand clear!" "Whiz-z-z!" went the huge blades, and, as the pilot switched on the current, the engines--powerful 100 horse-power ones, capable of some 1400 or 1500 revolutions a minute--broke into their wonderful song, and with a final word of parting from the Squadron Commander, the machine taxied off rapidly over the level turf. "Burr-r-r-r!" The air seemed full of a mighty sound, and a terrible vibration filled the heavens. It was the song of the aeroplane. At a hundred yards, in response to a very slight movement of the joy-stick, the winged creature leapt into the air, then circled around once or twice, climbing rapidly up to a couple of thousand feet, and made off south by south-east. The first whisper of dawn came out of the east as the hornet headed off towards the great city, for a filmy streak of grey, followed by a saffron tint, appeared in the sky low down on their left hand. The stars overhead began to fade and disappear, as though withdrawn into the vaulted dome overhead. Then the saffron turned to crimson, and soon the eastern horizon was aflame with light, for, as the machine rose higher and higher, the horizon broadened, and the whole earth seemed to lie at her feet. Now they were over the city, and the pilot laughed joyously, for he was exhilarated by the bracing air which rushed past him at a tremendous rate. "Look there, Jock," he cried, pointing down far below, where, through the gloom which still enfolded the lower regions, a faint silvery streak showed where the majestic Thames rolled down under its many bridges to the sea.