Next came an exposition of the part allotted to the Flying Corps. No German machines could be allowed near enough to the lines for any observation. We must shoot all Hun machines at sight and give them no rest. Our bombers should make life a burden on the enemy lines of communication. Infantry and transport were to be worried, whenever possible, by machine-gun fire from above. Machines would be detailed for contact work with our infantry. Reconnaissance jobs were to be completed at all costs, if there seemed the slightest chance of bringing back useful information.

No more bubbles of hot air were blown around the mess table. Only the evening was between us and the day of days. The time before dinner was filled by the testing of machines and the writing of those cheerful, non-committal letters that precede big happenings at the front. Our flight had visitors to dinner, but the shadow of to-morrow was too insistent for the racket customary on a guest night. It was as if the electricity had been withdrawn from the atmosphere and condensed for use when required. The dinner talk was curiously restrained. The usual shop chatter prevailed, leavened by snatches of bantering cynicism from those infants of the world who thought that to be a beau sabreur of the air one must juggle verbally with life, death, and Archie shells. Even these war babies (three of them died very gallantly before we reassembled for breakfast next day) had bottled most of their exuberance. Understanding silences were sandwiched between yarns. A wag searched for the Pagliacci record, and set the gramophone to churn out "Vesti la Giubba." The guests stayed to listen politely to a few revue melodies, and then slipped away. The rest turned in immediately, in view of the jobs at early dawn.

"Night, everybody," said one of the flight-commanders. "Meet you at Mossy-Face in the morning!"

In the morning some of us saw him spin earthwards over Mossy-Face Wood, surrounded by Hun machines.

Long before the dawn of September 15, I awoke to the roar of engines, followed by an overhead drone as a party of bombers circled round until they were ready to start. When this noise had died away, the dull boom of an intense bombardment was able to make itself heard. I rolled over and went to sleep again, for our own show was not due to start until three hours later.

The Flying Corps programme on the great day was a marvel of organisation. The jobs fitted into one another, and into the general tactical scheme of the advance, as exactly as the parts of a flawless motor. At no time could enemy craft steal toward the lines to spy out the land. Every sector was covered by defensive patrols which travelled northward and southward, southward and northward, eager to pounce on any black-crossed stranger. Offensive patrols moved and fought over Boche territory until they were relieved by other offensive patrols. The machines on artillery observation were thus worried only by Archie, and the reconnaissance formations were able to do their work with little interruption, except when they passed well outside the patrol areas. Throughout the day those guerillas of the air, the bombing craft, went across and dropped eggs on anything between general headquarters and a railway line. The corps buses kept constant communication between attacking battalions and the rear. A machine first reported the exploit of the immortal Tank that waddled down High Street, Flers, spitting bullets and inspiring sick fear. And there were many free-lance stunts, such as Lewis gun attacks on reserve troops or on trains.

The three squadrons attached to our aerodrome had to the day's credit two long reconnaissances, three offensive patrols, and four bomb raids. Six Hun machines were destroyed on these shows, and the bombers did magnificent work at vital points. At 2 A.M. they dropped eggs on the German Somme headquarters. An hour later they deranged the railway station of a large garrison town. For the remaining time before sunset they were not so busy. They merely destroyed an ammunition train, cut two railway lines, damaged an important railhead, and sprayed a bivouac ground.

An orderly called me at 4.15 A.M. for the big offensive patrol. The sky was a dark-grey curtain decorated by faintly twinkling stars. I dressed to the thunderous accompaniment of the guns, warmed myself with a cup of hot cocoa, donned flying kit, and hurried to the aerodrome. There we gathered around C., the patrol leader, who gave us final instructions about the method of attack. We tested our guns and climbed into the machines.

By now the east had turned to a light grey with pink smudges from the forefinger of sunrise. Punctually at five o'clock the order, "Start up!" passed down the long line of machines. The flight-commander's engine began a loud metallic roar, then softened as it was throttled down. The pilot waved his hand, the chocks were pulled from under the wheels, and the machine moved forward. The throttle was again opened full out as the bus raced into the wind until flying speed had been attained, when it skimmed gently from the ground. We followed, and carried out the rendezvous at 3000 feet.

The morning light increased every minute, and the grey of the sky was merging into blue. The faint, hovering ground-mist was not sufficient to screen our landmarks. The country below was a shadowy patchwork of coloured pieces. The woods, fantastic shapes of dark green, stood out strongly from the mosaic of brown and green fields. The pattern was divided and subdivided by the straight, poplar-bordered roads peculiar to France.