just before sunset the alerte entered the chenal de four, a dangerous and intricate passage between ushant and the brittany coast. not only does the water on either side of the deep channel teem with jagged rocks—many of them submerged at various states of the tide—but both flood and ebb set at from six to seven knots, sometimes obliquely across the narrow passage. to complicate matters further, the rise and fall of the tide is twenty-four feet at springs and eighteen feet at neaps.

by taking advantage of certain states of the tides, a vessel bound for brest and the biscayan ports from the english channel could save a long detour outside of ushant by making use of the four passage, but, in any case, the utmost caution is necessary. strangers are, in fact, warned that to attempt this channel without a pilot is entailing great risk.

to captain cain this hazardous locality presented no terrors. many a time during his naval career he had taken submarines between brest and portsmouth, and had lurked in the chenal de four waiting to turn the tables on the u-boats that preyed on the shipping converging upon ushant. now he was going to put the knowledge that he had gained legitimately to a perfectly illegal use.

"any sign of the fairy, mr. pengelly?" he inquired.

"no sir."

"all right. i'll carry on. quartermaster, keep those two towers in line—s. 5 e. is the course. mr. pengelly, see that the anchor is clear and fifty fathoms cable ranged on deck ready to let go."

the sun set in a vivid red sky. the lights of kermorvan and st. matthieu towers sent out their guiding beams. in a couple of hours the moon would rise.

still the alerte held on. presently the lookout reported a sail on the starboard bow. against the still strong afterglow in the western sky the intervening stretch of water appeared to be studded with rocky pinnacles.

"that's the fairy," declared captain cain to pengelly, who had rejoined him on the bridge. "she's brought up in four fathoms off beniguet island. no, we won't send out recognition signals.... hard-a-port, quartermaster.... meet her!... at that!"

the alerte, her speed reduced to five knots, appeared to be heading straight for a saw-like reef. another alteration of helm and she slipped past within half a cable's length of this ridge of rocks, eeled her way between two half-tide rocks and settled down on a course s.s.w.

"stand by!" shouted captain cain, ringing for the propellers to be declutched.

gradually the alerte lost way. a hoarse order from the bridge was answered by the rattle of cable heaving through the hawsepipe. snubbing gently at the tautened cable, the pirate submarine swung round head to tide within two hundred yards of the falmouth lugger owned by the redoubtable cap'n silas porthoustoc.

the fairy had a riding-light on her forestay, but no hail came from her deck. the alerte, having extinguished her navigation lamps, hoisted her anchor-light. to any observant breton fisherman there was nothing to excite suspicion. small craft bringing up to avoid a foul tide were fairly common objects in the vicinity of the chenal du four.

since broadmayne's and vyse's "promotion" to the starboard watch, the chums had spent much of their time on deck. their new messmates, now that they recognised them as such, were apt to be either patronising or rudely inquisitive. they looked upon the two chums' predicament—being forced to work without payment—as a huge joke, especially as rollo and the sub were obviously men of a different social standing. hence it was not surprising that the late crew of the ibex kept to themselves as much as possible.

the sub knew roughly the position of the alerte. although he had never before been through the four passage, he realised from his previous knowledge of ushant light that the anchorage was between some of the islands off the westernmost part of the brittany coast.

"wonder what that vessel is?" he remarked, pointing to the fairy's riding-light. "if she's a breton fishing craft, we might swim off to her."

"not in this tideway," objected vyse, for the water was hissing and seething past the side of the alerte. "we might when the tide eases off. it's bound to just before high water. 'sides, the moon will be up soon."

they waited and watched, conversing in low tones. the alerte's deck was practically deserted. there was a look-out man on the fo'c'sle. occasionally some of the hands would emerge from the close atmosphere of the crew's quarters for a breath of fresh air. but no one seemed to take the slightest notice of the two chums.

presently the moon rose behind the gaunt brittany hills—a huge red disc, that soon appeared to diminish in size and assume a vivid yellowish hue. it was now one bell and the first watch.

"that's not a frenchman," declared the sub, as the slanting moonbeams fell athwart the bluff outlines of the penzance boat. "she's a west-country lugger, i'll swear. wonder what she's doing here?

"perhaps her skipper's a pal of the pirate captain," suggested vyse.

"not likely," objected broadmayne. "they didn't communicate with each other when we came in. i was looking out for that. 'sides, it's hardly feasible that a sailing lugger, if she were acting as tender, would show up within a few miles of the great french naval port of brest. it would be far safer to get in touch fifty miles from land."

"that's so," agreed vyse. "and that brings us back to our original proposition. how's this for a scheme. the lugger's now almost dead astern of us. the tide's easing a bit. the alerte's look-out is for'ard, consequently he can't see what's goin' on aft. we can lower ourselves over the stern, swim off to the lugger and get aboard by her cable, if there's nothing better. we'll warn her master of the undesirable nature of the alerte and offer him a hundred quid if he'll weigh at once and give us a passage to england."

"then the sooner the better," said the sub briskly. "it will be another hour and a half before the look-out is relieved. if he misses us, he'll probably think we've gone below. his relief will know we're not."

their preparations were quickly and silently made. they sacrificed their footgear. broadmayne took off his black oilskin, rolled it neatly and stowed it away under the platform of the sounding machine aft.

the next step was to drop the after-fall of one of the quarter-boats overboard. had the alerte been a genuine tramp steamer the fugitives would have to run the risk of being seen through the cabin scuttles, but her cabins being within the hull of the submarine, were artificially lighted.

broadmayne gave a swift, comprehensive look for'ard. the look-out man was still in the fo'c'sle. he was resting one leg on the low bulwark, and was gazing stolidly in the direction of st. matthieu lighthouse. evidently he considered his job a merely formal one, and was making the best of his trick by indulging in fanciful speculations of what he would do with his rapidly increasing wealth.

giving his companion a reassuring nod, the sub cautiously slid over the rail, gripped the rope and lowered himself slowly.

"ugh!" he mused. "feet first; rotten way to take the water. i'll bet it's beastly cold."

but to his surprise the sea was fairly warm. it made him shiver when the water rose above his ankles and knees, but directly he was immersed to his neck he felt no further discomfort.

it was true that the hot tide had slackened. it had decreased from six to about three knots, or a rate equal to that of a brisk walk. still hanging on to the rope, he felt himself being swept aft until his feet were almost showing above the surface.

he dare not let go until vyse was almost at the water's edge, otherwise he would be swept far to lee'ard before his chum was ready to cast himself off. keeping together for mutual encouragement was part of the prearranged plan.

down came vyse, hand over hand. the two chums were now up to their necks and still hanging on to the rope. both realised that if they were swept past the lugger by some not unusual freak of the tidal current, they were as good as lost.

"ready?" whispered broadmayne. "breast stroke; don't speak."

they released their hold and struck out. the towering hull of the alerte seemed to be moving with great rapidity. almost before they realised it, they were clear of the shadow of the poop and were swimming strongly in the moonlit sea.

now they could clearly discern the lugger as she strained and tugged at her tautened cable. the water was frothing against her stem-band. but for the cable, it looked as if she were forging ahead under power. every now and again she would sheer madly, so that at one time the swimmers were heading straight for her; at another—it looked as if they would be swept half a dozen yards away from her.

by good luck, broadmayne grasped the cable. with a jerk that well-nigh wrenched him away, his body swung round in the fierce current. the next instant, vyse secured a hold.

then the lugger commenced to sheer again. the cable dipped, dragging both men below the surface. not daring to let go, they hung on, holding their breath until the iron chain tautened again, lifting them both waist high out of the water.

"you go first," gurgled the sub. it was a hazardous business, clambering up on the underside of a vibrating chain at an angle of about forty-five degrees. although it was not far to go, the difficulty increased as vyse approached the vessel's bows. there was a danger of being nipped between the cable and the small, iron-shod hawsepipe, with the additional possibility of his arm being jammed between the chain and the lugger's stem-head.

keeping clear of these dangers, vyse hung on, looking for a means of getting in over the bows. suddenly he caught sight of a stout piece of line by which the chain bobstay had been triced up to prevent it being chafed by the cable. it might hold—it might not. at any rate, he decided, if it did carry away, he could make a grab at the bobstay.

desperately, rollo made the attempt. the rope gave slightly as he transferred his weight to it. the next instant he had thrown one leg over the massive bowsprit. it was then a fairly simple matter to haul himself up and across the heavy spar.

by this time, broadmayne was attempting the ascent; water poured from his saturated clothing as he drew himself clear. he was breathing heavily, but the grinding of the cable and the rush of the tide completely drowned his laboured gasps. with less caution than his chum had shown, he allowed the knuckles of his right hand to be barked by the surge of the chain. had it not been for vyse's prompt assistance, the sub must have relinquished his hold.

for quite five minutes the two men crouched on the lugger's fore-deck, too exhausted to move. there was no one of the crew on deck. a faint gleam was thrown obliquely from the half-closed fore-peak hatchway. aft, the fluted glass skylight over the skipper's cabin was illuminated from within.

"come aft," whispered broadmayne.

in stockinged feet, they crept cautiously past the huge old-fashioned windlass, made their way along the narrow space between the tarpaulined hatch covers, over the hold, and gained the small aperture leading to the cabin.

the sub knocked softly upon the door.

"that be you, garge?" demanded a deep, rolling voice. "come in."

accepting the invitation given to the absent "garge," whoever he might be, broadmayne opened the door. had it not been for the voice, the sub would have formed a first impression that the cabin was untenanted.

under the skylight hung a swinging lamp, with a polished brass deflector. immediately under the lamp was a table that at one time had been polished mahogany. now it was scratched, tarnished and blackened, the captain evidently being in the habit of knocking out the glowing embers of his pipe upon the table.

at the after end of the cabin was a long bookcase above a settee. on either side were seats with lockers under, while above the seats were cavernous recesses with large sliding doors.

one of the latter was partly open, revealing a hairy-faced man lying fully dressed on a bunk, with a heap of blankets covering him from his feet to the point of his chin. apparently he was still wanting additional warmth, for a coal fire blazed in a brass-lined fireplace—the skylight was shut, and, until broadmayne opened it, also the door.

cap'n silas porthoustoc's astonishment at the sight of two saturated strangers was quite equal to that of the sub and his companion, when they caught a partial view of the old man "stewing" in the hot and unpleasantly close air.

"who are ye, an' what you'm wantin'?" inquired cap'n silas, embellishing his inquiry with half a dozen totally different adjectives.

"it's all right, captain," replied broadmayne soothingly, "we've just swum off from the vessel brought up ahead of you."

"desarters, eh?"

"sort of," admitted the sub.

"an' you'm thinkin' the fairy is a nursery for cut-an'-run sailormen?" rejoined captain porthoustoc. "you'm come tu wrong ship, you'm have. best swim back along 'fore there's trouble."

"look here, captain," began broadmayne firmly.

before he could say more, the skipper of the fairy thrust back the sliding-door of his bunk and rolled out, bringing with him an avalanche of blankets, a heavy pilot coat, and an oilskin.

"wot's this?" he demanded. "threatenin' me in my own cabin, aboard my very own ship?"

"not at all, captain," said the sub hurriedly. "we want your assistance. we'll pay you well."

"pay me well!" echoed captain silas scornfully. "can show the colour of your money, belike?"

"we'll give you a hundred pounds if you'll put us ashore anywhere in england," said broadmayne. "possibly the admiralty will pay you considerably more. the vessel we were on is a pirate."

"'slong's she don't do aught to we, i'm content," replied captain silas. "howsomever, a hundred pun' is worth a-pickin' up. but if she be a pirate, as you say, what happens if so be she sends aboard us to look for ye?"

"if you up-anchor and get under way at once she'll be none the wiser," suggested the sub. "if you think she'll chase you across the channel, there's no reason why you shouldn't run for brest. you'll get your money just the same."

"can't start afore the tide sets to south'ard," objected captain silas. "but i'll tell you what: i'll stow you away. you can lay your life on it, you'll not be found. a hundred, you said?"

the sub reiterated his promise.

without another word the skipper of the fairy kicked aside a narrow strip of coco-matting, fumbled at a small circular hole in one of the floorboards, and at length raised a double-width plank about eighteen inches square.

the light of the cabin lamp revealed a cavernous space, with sloping sides and massive oaken timbers. floor there was none, the narrow space above the kelson being packed with rusty iron bars. a cold and evil-smelling draught ascended, while with every roll of the lugger the bilge water sluiced and gurgled over the iron ballast.

"our clothes are wringing wet," observed vyse, stating what was an obvious fact, for they were standing in puddles, while the heat of the closed-down cabin caused the wet material to emit a regular haze of vapour.

"off wi' 'em, then," said cap'n silas shortly. "i'll hide 'em. blanket a-piece will serve till they'm dry."

the two chums were in the final stages of disrobing when one of the hands tapped on the skylight.

"she be hailin' us to come alongside, cap'n," he announced.

"pretty kettle o' fish you've made," he exclaimed. "pirate, you say she be. well, 'tain't no use us kickin'. we'll drop alongside of 'er, an' they can search till them's tired. they'll never find you. down you go. keep clear of yon propeller shaft."

gingerly the chums gathered the loaned blankets about them, toga-wise, and dropped down upon the ballast. the trap-door was replaced and the coco-matting relaid. in utter darkness the fugitives crouched, listening to captain stamping about before going on deck.

soon the fairy's motor started, but the shaft gave no sounds to indicate that it was revolving. then came the clank of the pawls of the windlass, as the cable came home, link by link. the gentle purr of the engines increased to a loud, pulsating roar. the clutch was engaged, the propeller shaft began to revolve—perilously close to vyse's feet it sounded—and the lugger began to forge ahead.

she had not been under way for more than three minutes when the motor stopped and her stout hull quivered as she bumped alongside the alerte.

"now what's going to happen?" thought broadmayne. "the blighters are coming on board."

there was a terrific din on deck. men were stamping and running about, heavy weights were dumped down, the hatch-covers over the hold were thrown back.

the sub could hear men's voices as they shouted to each other, but the motor roar intervening between them and the fugitives prevented the sub hearing what they were saying.

"they're making a pretty strict search," whispered vyse.

"'ssh!" cautioned his companion. "there's some one in the cabin. it's pengelly, by jove!"

"all in small packages... easily got ashore ... he told you to do that? look here, silas, you'd better not... the cave behind your kitchen... we'll arrange all that later... part brass rags within a fortnight... it'll pay you far better... then that's a deal?"

the sub broke out in a gentle perspiration. from the scraps of conversation he had overheard, there could be but one explanation forthcoming. pengelly and the master of the lugger were plotting —against whom? captain cain, without a doubt. that was interesting. but the disconcerting part was: what was the skipper of the fairy's attitude towards the two men hiding in the bilge? would it pay him better to give them up, or to keep faith with them and so gain the promised hundred pounds?

"mr. pengelly!" shouted a voice, which broadmayne recognised as that of captain cain.

"ay, ay, sir!" replied the second in command.

the fugitives heard the sound of pengelly's boots upon the ladder leading on deck. the fairy's skipper followed.

"the old sinner," whispered vyse. "i thought he was going to betray us."

"i don't think so," replied the sub. "the promise of a hundred pounds is our sheet-anchor. by jove! i can see some interesting developments before very long."

"what developments?" inquired the other in a low tone.

before broadmayne could reply—it was quite safe to maintain a cautious conversation, since the uproar on deck would deaden every sound below—a minute shaft of yellow light played upon the sub's hand. he knew what that meant. the coco-matting had been removed, thus allowing the lamplight to enter the thumbhole in the covering to their place of concealment.

the next instant the trap hatch was thrown wide open. standing close to the opening was captain cain, a revolver in his hand and a sardonic grin on his face. behind him were four of the alerte's crew. silas porthoustoc, chuckling audibly, was stationed in the narrow doorway, while over his shoulders appeared the grinning faces of pengelly and barnard the boatswain.

"out of the frying-pan, eh?" exclaimed captain cain mockingly. "you two have vastly underestimated the intelligence of the alerte's ship's company. i'll deal faithfully with you for deserting, my lads. now, out you come."

dejected and humiliated, broadmayne and his companion emerged from the loathsome place of concealment. their clothes had vanished. clad in nothing but cap'n silas's blankets, they beat an ignominious retreat, running the gauntlet of a fire of rude chaff from the alerte's crew as they hurriedly went below to their berths. in the eyes of the rest of the ship's company they were nothing more or less than skulkers, who took every opportunity of dodging their share of work. and as such they had no sympathy from the piratical crew of the alerte.