It was shortly after midnight that Derek was roused from his straw bed by the sounding of a tocsin-gong warning of the approach of hostile air-craft.

The young pilot received the intelligence without emotion. He was getting accustomed to being turned out at unearthly hours, and the regularity of the proceedings made him stiff, especially when, in nine cases out of ten, the Hun failed to put in an appearance.

With very few exceptions, the German airmen now rarely flew over the British lines during the hours of daylight. If they did, they generally paid dearly for their temerity, as frequently a whole squadron of chasers promptly pounced upon them. But at night there were opportunities, and the Boche was not slow in seizing them. Rising to an immense height above the aerodromes, they could glide, unseen and unheard, for miles, until they imagined that they had avoided the British air-patrols.

Consequently alarms were frequent, but in the darkness the Boche often went wide of his objective, unless that objective happened to be a hospital, the roof of which was marked at night by an illuminated Red Cross—a Red Cross to a Hun being like a red rag to a bull.

"\'Nother of \'em," he muttered. "Getting fed up with dud calls. Jack, turn out, you lazy blighter!"

Kaye, who was fully dressed, with the exception of his boots, rolled heavily from his uncomfortable couch. In the dim light of a guttering candle he commenced to pull on his footgear, and took the opportunity to philosophize.

"Deuced queer how a fellow gets used to things in this jolly old war," he began. "Didn\'t know what it was to be wakened out of my beauty-sleep until some time in 1915. No wonder my thatch\'s getting a bit thin on top. And now, when a Boche is about dropping his rotten eggs, we grumble because it\'s a cold night and we have to turn out. Funny thing too: yesterday a Tommy came up and saluted, and asked if I remembered him. Wiry sort of chap, as hard as nails, smothered in mud, an\' just off back to a rest camp. He was the pater\'s gardener, a fellow well over forty, who didn\'t know one end of a gun from t\'other back in \'14. Now he\'s a sergeant and a D.C.M. man, while his young brother, a hefty lout who used to weed the parson\'s garden when he wasn\'t poaching, has managed to get exemption as an engineer. Lord! after the war, won\'t there be a gulf between men and slackers?"

"One will feel sorry for the slackers. They won\'t be able to hold their heads up," remarked Derek.

"Not they," corrected Kaye, giving his bootlace a vicious tug. "They\'ll have whole skins and fat purses. The blighters who\'ve done all the work and gone through all the danger will be back numbers when the war\'s over—if it\'s ever going to be over."

"I remember a school-chum of mine," continued Daventry, "Brown, by name; a fellow who hated sea-water like poison. Last I heard of him was that he was in command of an M.L.—they call M.L.\'s Harry Tate\'s navy, I believe, but the men who run them are all O.K.—and he\'s been given the D.S.O. for some harum-scarum work off the Belgian coast. They are fond of putting square pegs into round holes in the services, but sometimes the edges of the pegs get worn down, and then they fit right enough. By Jove! That was a near one. Time we sought our little funk-hole."

A crash, followed by two others in quick succession, gave plenty of indication that Fritz was setting to work. Then the antis joined in the deafening roar, firing at a swiftly-moving object showing like a silvery gossamer in the rays of a searchlight.

It was less than fifty yards from the two chums\' hut to the mouth of the dug-out, but during their deliberate and leisurely progress across the open ground Daventry and Kaye had an opportunity to observe some of the results of the raider\'s work.

A quarter of a mile away a fire was blazing fiercely. In that direction lay the hospital. Nearer, but in the opposite direction, was another but smaller blaze. A babel of excited voices could be heard between the crashes of the anti-air-craft guns and the explosion of the bombs.

"Chinks\' quarters," remarked Kaye laconically.

"Yes; it\'s the Chinese compound," agreed Derek. "Pity the Boche didn\'t make a mistake and drop an egg into the barbed-wire enclosures to the right. There are about four hu............