"Hanged if I know how to answer that argument," explained the Englishman to a staff officer. "Evidently it's a case of reprisals. I don't know what's to be done, but there'll be a fine old row over the business."

There was no more rest for Derek after that. Returning to his quarters, he found that his batman had made his bed and tidied his room with a precision that one would hardly expect to find within a few miles of the front. There was also a steaming hot cup of tea ready; and a batman who attends to his master's personal comfort under adverse conditions is a priceless treasure.

Derek sipped his tea gratefully, washed, shaved, and prepared for the coming day's work.

CHAPTER X

Kaye's Crash

At 10 a.m. Derek Daventry started off in EG 19 on patrol. Kaye, flying a machine of the same type, had risen five minutes earlier. According to instructions the two airmen were to make a reconnaissance above the important railway junction of Les Jumeaux, where the Huns were supposed to be detraining a number of tanks for the avowed purpose of holding up the British and French counter-advance.

Everywhere the Huns had been held. In certain sectors their line was cracking badly. There were evidences of a retreat on a large scale. Demoralization was sapping their ranks like a canker, while the morale of the Allies, never low in spite of reverses, was again on the rise. At the same time Fritz still had a certain amount of kick left in him. He might strive to stave off disaster by rallying the best of his badly-shaken troops and attempt another break through, in the hope that if the operation were successful he might be able to effect a possible peace by negotiation.

It was therefore necessary to keep a vigilant watch upon the Germans' back-areas, to observe any great concentration of troops or material, and to continue harassing his lines of communication; and the only way to do this was by means of that juvenile but virile branch of the service, the R.A.F.

That day machines were up in hundreds. The sky seemed stiff with biplanes and monoplanes, all bearing the distinctive red, white, and blue circles. Each machine had a definite object in view—a set task to perform.