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 hundred prussians there, men of the lowest type of hun i've ever met. hallo! what's fritz doing?"

both officers stopped and gazed aloft. the german biplane was diving rapidly right into the eye of the searchlight. it was a deliberate move. the hun was descending under perfect control, with his engine running all out, straight for the searchlight projector.

"look alive, old man!" exclaimed derek, gripping his chum by the arm and forcing him into the dug-out.

the two were only just in time, for as they descended the steps they could hear the rattle of a machine-gun and the splaying of hundreds of bullets upon the concrete.

five minutes later the raid was over. the daring hun had got away apparently untouched. not only had he bombed the hospital, the chinese compound, and part of the aerodrome, but by flying down the path of the searchlight and making good use of his machine-gun he had "wiped out" the entire crew of the searchlight itself.

while deprecating the wanton attack upon a red cross building in no mild terms, the r.a.f. men were not slow to praise the nerve and daring of the boche, who, braving the archibalds, had descended to within fifty feet of the ground in order to use his machine-gun with the deadliest results.

"have a gasper?" asked kaye, tendering a battered cigarette-case in which every dent had a story attached to it. "there's nothing like a cigarette when you've been turned out."

"thanks, no," replied derek. "think i'll try a pipe before i turn in again. wonder if there'll be any more stunts? hope not, as i'm on patrol to-morrow—or to-day, rather," he added, glancing at his wristlet-watch.

a minute or so later derek knocked the ashes from his pipe, dived between the blankets, and was fast asleep, as if a hostile bombing-raid was merely one of the side-shows of life.

just as the first streaks of dawn stole across the eastern sky the airmen were turned out by another alarm. officers and men doubled on to the parade-ground to the accompaniment of a regular fusillade of bombs detonating at no great distance away.

"no. 1 flight—in fours—right—double march!"

no. 1 flight, detailed for special duty, promptly hurried off, while the remaining flights were ordered to stand at ease.

the nature of the commotion was soon obvious. the chinks, as the chinese labourers are termed, were seeking revenge for the deaths of several of their fellow-countrymen during the raid. with true oriental cunning and stealth they had raided a store containing live mills's bombs, and, armed with these sinister weapons, had surrounded the barbed-wire enclosure where the german prisoners were caged.

before the handful of sentries realized what was taking place a terrific fusillade of bombs was directed upon the cage, and the strafing was still in progress when the airmen arrived upon the scene.

it did not take the new arrivals long to restore order. the chinamen, expostulating and explaining in their quaint "pidgin" english, were relieved of the few bombs that had not been thrown across the barbed wire, and were marched back under escort to their compound.

"bochee-man him dropee bomb on englishman," declared an old coolie imperturbably. "englishman he dropee bomb on bochee-man—can do. bochee-man dropee bomb on chinaman; him dropee bomb 'on bochee-man—no can do."

the british overseer explained that the victims of the chinese were prisoners of war and must be protected; to which the chinamen replied that they, too, were in a compound enclosed by a wire fence.

"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.