ten minutes later the boats were in the turmoil of the troubled water caused by the swirl of the tide over thorbury ledge. had it been light enough for anyone standing on the headland to watch the two diminutive craft struggling through the broken water, he would doubtless have expected to see the frail cockle-shells founder under his eyes.

it was hazardous work, certainly; but by this time derek had the utmost confidence in the seaworthiness of his two craft. often hidden from each other by the intervening crests, the boats behaved wondrously; but the youthful officer in charge was relieved to know that wind and tide were in the same direction. had it been otherwise things might have been different. from the headland it was now plain sailing, for in the gathering light the slender tower of the lighthouse at fort churst could be discerned, standing out clearly against the dark background of the well-wooded hills. in forty minutes both boats were passing through the narrow channel. signals were exchanged with the batteries, and the welcome order to proceed was received.

it was now comparatively smooth water. the crews, recovering from their malady, were able to sit up and take nourishment in the shape of bread and bully beef. more, they began to take a lively interest in their surroundings, although the aspect of that land-locked stretch of water in war-time and in november was far different from what it had been previous to august, 1914, when the sea was dotted with the sails of countless yachts.

"wonder if it will ever be the same again?" thought derek. "one thing's fairly certain: we won't see the german emperor afloat here, unless as a prisoner of war on a british battleship."

over a vast observation minefield the boats glided serenely. fifty feet beneath their keels were cylinders of powerful explosive that at the touch of an electrically-connected key ashore would blow a hostile ship to atoms. farther on there were mechanical contact-mines, moored fathoms down so that a vessel of the deepest draught could pass unscathed but should a u-boat attempt to nose her way in by creeping just above the bottom of the sea, her fate would be swift and terrible.

"keep a sharp look-out for the gateway," ordered derek, as he placed a fresh man at the helm. "it's getting a bit misty, and we don't want to run full tilt against the boom."

the boats were now nearing the innermost line of anti-submarine defences of the western approach to the greatest naval harbour in the world. right across the water-way was a triple line of massive wire hawsers, supported by barrels at frequent intervals. so much was visible; what was not visible was a wondrous complication of nets, explosive charges, and other effective anti-submarine defences. britain's sure and safe shield was taking no undue risks with fritz and all his evil works. to enable authorized vessels to pass, a gateway had been constructed. between two large craft moored a cable's length apart there was a movable section of the barrier, and towards this the two motor-boats steered.

"motor-boats ahoy!" hailed an officer from one of the guard-ships. "you are to proceed to bull roads and await further orders from the s.n.o."

against this mandate there was no appeal. the word of the senior naval officer was more than law. doubtless it meant irritating and apparently needless delay, but, whatever the object of the order, it had to be put into effect without delay.

"aye, aye, sir!" shouted derek in reply. he knew perfectly well that non-compliance would result in a six-pounder shell fired across his bows, and almost immediately a salvo from the guardship's quick-firers.

"port helm!" continued daventry, addressing the coxswain. round swung his boat; the one astern instantly followed suit, and a course was shaped for bull roads, an open anchorage barely two miles distant.

arriving here the boats had orders to anchor, and for four long hours they rolled heavily in the tide-way. naval patrol-boats of all sorts and sizes passed continually, but none appeared to pay the slightest attention to the two strangers within their gates. it was not until well into the afternoon that a patrol-boat eased down within a few feet of derek's craft.

"you can proceed," announced the officer.

"why have we been detained?" asked derek, wondering at the bald announcement and the lack of explanation.

the sub-lieutenant r.n.r. shrugged his shoulders.

"ask me another, old sport," he replied. "if you want to carry on do so at once, before the old man puts another stopper on you. bon voyage!"

the motors were started up; foot by foot the chain cables were brought on board until the anchors, their palms smothered in blue, slimy clay, were hauled up and secured. then, in the gathering twilight, the boats headed for their destination. by this time the mist had increased considerably. visibility was a matter of a couple of hundred yards. it was bitterly cold, the air being raw and damp. "verily," thought derek, "motor-boating in november differs considerably from yachting in august."

at length the huge air-sheds of the wagshot station loomed up through the mist. ordering half-speed, derek brought his boat alongside the pier, and signalled to the second craft to lie up alongside him.

"where are you from?" enquired a great-coated individual from the pier-head—the officer of the watch.

"from. sableridge," replied derek. "we've come to take away a sea-plane."

"first i've heard about it," rejoined the o.w. "you'd better see the adjutant. you're stopping here the night?"

"'fraid there's no option," replied daventry.

"right-o! moor your craft out there. i'll send a duty-boat out to take off the crews."

"out there" was a partially-protected anchorage, about a hundred yards from the pier. the boats pushed off and made for their appointed stations for the night, derek taking particular care that each boat was properly moored with both anchor and kedge.

this done the crews were taken off. visions of a hot meal first for his men and then for himself (for it is an unwritten law that officers must first provide for the comfort of their crews before "packing up" themselves) were rudely shattered when the officer of the watch appeared.

"i've seen the adjutant," he announced. "you'll have to take those boats across to bumble creek. they'll be in the way of our flying-boats if they stay there."

derek felt inclined to use forcible language; to enquire pointedly why these instructions could not have been given him before the elaborate process of mooring the boats had commenced. to be ordered at the end of a strenuous day's work to undertake another hour's toil was a tough proposition for the cold and hungry men to tackle.

"i'll send the duty-boat to pilot you," continued the o.w. "she'll bring you back to the station." thankful for small mercies derek turned his men to. it required fifteen minutes of hard work to unmoor and get under way. fortunately the duty-boat was standing by, for the run across to bumble creek meant crossing an arm of the sea that was constantly alive with traffic.

once more the two boats were secured for the night, this time alongside a hulk. it was pitch dark when derek and his men returned to wagshot air station.

having seen his men installed in their temporary quarters and provided with a hot meal, derek made his way to the officers' mess. instead of a bright, cheerful building like that at sableridge, he was directed to a large hut, which was divided into two large rooms and a few smaller ones.

"there's the ward-room, sir," replied a girl in the uniform of the w.r.n.s. "the steward will arrange for dinner and quarters."

the ward-room was a wood-lined but devoid of almost every comfort. floor and walls were bare, except, in the case of the walls, for a few technical prints of sea-planes and flying-boats. in one corner was a table piled high with leather coats, helmets, gloves, and other garments affected by airmen. a fire burned dully in a large grate, round which were seated, shoulder to shoulder, half a dozen young "quirks".

they greeted daventry with supercilious glances; then, having surveyed him in stony silence, they resumed their conversation in loud tones, apparently with the idea of impressing the new arrival with their importance and familiarity with life in town.

"cubs—utter outsiders," thought derek. "and what a bear-garden this mess is."

chilled both mentally and physically, daventry went out, preferring to pace the bleak parade-ground until dinner was served to remaining in such inhospitable company.

dinner over, payment was promptly demanded—another difference compared with the way they ran things at sableridge, where any strange officer who happens to blow into the mess is given hospitality and never charged for his entertainment.

"i've secured a room for you in the new building, sir," announced the steward. "there'll be a car ready to take you up in twenty minutes."

derek spent the time in revisiting his men. they were none too happy, although making the best of things. there were abundant evidences that wagshot was what is known as a "mouldy station", but worse was to follow.

up rattled the car; derek took his seat, and off the ramshackle vehicle went. it may have been owing to the state of the road, but the jolting of the car was worse than any he had experienced in france. over narrow-gauge railway lines, sometimes grinding on shingle, at others sinking in sand and mud, the car held on its way. the road was narrow, with the sea on either side, for wagshot air station is built on a natural peninsula of which the isthmus is long, narrow, and rugged. the shore was littered with the skeletons of burned sea-planes and flying-boats, the gaunt framework of which stood out clearly against the misty sky.

presently the car gained the mainland, swung round several sharp corners, and pulled up outside the quarters known as the new buildings.

an orderly conducted derek to his temporary quarters, which were well termed "new", for they were still in the builders' hands. after traversing several hundred yards of corridors that looked like those of a prison, with dozens of doors exactly alike, his guide stopped, produced a key, and threw open the portal of the "cabin".

it was a small room lighted by a feeble electric lamp. walls and floor were of concrete that literally ran with moisture. there was neither carpet nor rug on the floor, while the furniture was of a most spartan character, comprising two beds—one already occupied by a soundly-sleeping officer—a trestle table, and a chair.

"hope you'll be comfortable, sir," remarked the batman ironically. he had seen strange officers "blow in" many times before, but he could not resist the temptation to indulge in mild plaisanterie. "lights are turned off at ten-thirty," he added, with infinite relish; "and if you shut the door on the outside you can't get in unless you come to me for a key, sir."

left to the sole companionship of the soundly-snoring officer, derek prepared to turn in. investigations showed that the bed had a wire mattress, a straw pillow, and two army blankets. the pillow showed signs of disintegration; the blankets felt damp and smelt musty. daventry felt inclined to use strong language. on active service on the western front he would have borne the discomfort with equanimity; in a permanent home-station there was no excuse for the wretched accommodation.

kicking off his sea-boots and tunic derek turned in practically "all standing", to pass a fitful night, and to awake to find a white mist enveloping everything.

he had breakfast with about twenty young officers, the meal consisting of a tablespoonful of luke-warm porridge, two square inches of american bacon, bread, margarine, and tea. before he left the building the messman presented a bill for half a crown for this sorry repast.

upon arriving at the pier-head derek found that his men had fared no better, and in spite of the thick fog they brightened up considerably when their officer announced his intention of getting away from wagshot air station "even if it rained ink".

the first step was to induce the officer of the watch to send the duty-boat over to bumble creek to fetch the motor-boats. this was successfully accomplished, notwithstanding the fact that twice the duty-boat ran aground, fortunately on soft mud and on a rising tide. by ten o'clock derek's two craft were alongside the pier, and the sea-plane that had to be towed back to sableridge was prepared for her voyage.

"the fog's lifting, i fancy," remarked the officer of the watch. "you'll be able to get away to-day after all."

"i mean to," rejoined derek grimly.