After climbing rapidly, and circling round the aerodrome once or twice, the machines made off, each to reconnoitre the section of the line allotted to it.

The hornet carried two Lewis guns, with plenty of ammunition, for when an aerial patrol sets out on a flight, one never knows what duels he may have to engage in before he returns. The hornet had this advantage over the other machines, which were of an older pattern: she had a higher speed, was a better climber, and with her improved controls she could manoeuvre more quickly than any other machine yet made.

"Gee whiz!" cried Jock down the speaking tube, which ended close to the pilot's ear, "but she's climbing."

"What is it?" yelled back the pilot, half turning his head so that his mouth came near to the end of the tube.

"Three thousand feet," came the answer.

"Good! Then we'll make a bee-line and cross the trenches. Look out for 'Archie'!"

The dawn had broken by now, and away in the east the gloom was lifting, but down below it was still wrapped in mist and darkness. It was the hour of standing-to. Down below thousands of eyes would be straining through the obscurity to find that speck in the heavens whence came that whir-r-ring sound.

But upward and onward went the hornet With a stern, strong beat of power in her twelve-cylindered engine. Nearer and nearer she came to that long line which stretched from the sand-dunes of Belgium away to Switzerland. The observer was already keenly surveying the landscape through his glasses as the light broadened, and the countryside revealed itself.

A silvery streak lay beneath them; it was the River Ancre. Now a broad white patch of roadway came into view. It was the main road from Albert to Bapaume. As they came out of a bank of rolling mist and fog, a few red roofs and a church tower next came into view, standing just where four roads met.

"Contalmaison?" queried Dastral, and Jock, after a brief reference to his waterproof map, called back: